Volume 28 (1874) (430 pages)

January 24, 1874.] MINING AND SCIENTIFIC PRESS. 55 User: INpoRMATION. Why do Paints Dry ? It was proved long ugo, that linseed oil, when exposed to the air, becamo covered with a hard crast, and that this crast is produccd by the ubsorption of oxygen. Pulnt mado from oil and coloring matter alone does not dry because it narts with any thing or because it gives off any vapor, bnt becauso It hccomea bard hy the action of the atmosphere. It is stated in a recent work on paints thut oil does not form even the basin ofa paint. This is more technical than judicions. Oil alone, if laid on in thin, successive coats, hecomes very hard and forms a durable and impervious varnish, which protects the wood beneuth almost as well as paint would do, at least so far as nioistare und sir are concerued. Against the sun's raya, however, itis a poor defense. But as it hos been found impossible to apply a eufficient coat of this varnish inany thing like u reasonable time, the oil has in general heen mixed with various colored powders or pigments, which thicken it and thus enshle us to lay on u heavier coat. Many of these pigments have no action ou the oil, and it is always best that they shonld have no action. Compnunds of lead, which are known to form chemical compounds with the oil, are amongst the very poorest paints, White lead is confessedly one of the least efficient of all our preservative agents, the authority referred to to the oontrary notwithstanding. When paint ia applied to a fresb surfnco of wood, it often appears to dry in a short time. In this case, however, it will be found that tbe aint has not really dried, hut thut tho oil has eer absorbed by the wood; and in tbis case the pigment is often left in tbe form of a friable powder, loosely adberent to the surface to which it was applied. It rubs off very easily. This occurs to uless extent with white lead tban with uny other paint, eimply heeause the lead combines witb the oil and holdsit on the surface, thus preventing its sinking in. We are inclined to regard this feature as one which confers no advantages upou white lead. It is prnbably better for the wood that as mucb oil as possihile should soak into it, and it is no grest disadvantage tbat the paint of the first coat should not adbere strongly. Where economy is un objeet, the absorption of the oil is prevented by first applying a coat of cheap sizing. The size fills np the pores of the wood, and prevents the sinking in of the oil. For in-door work, this answers very well, bnt for out-door purposes it is objectionable, But all paints do not dry in the manner that we have mentioned. For in-door work, where itis desirable that the paint should dry rapidly and have a dead or non-reflecting surface, paint is generally mixed with turpentine. This is a volatile oil, which passes off rspidly when exposed to the air, and thns leaves the paint behind as a thin crust. This ability of the paint to resist atmospheric influences is tbereby lessened; and this, for in-door work, is a mutter of no conseqnence. It wonldbe wrong, perhaps, to say that the oil of turpentine passes off entirely by evaporation, as a small portion probably becomes oxidated and remaing behind. The amonnt so retained is, however, very small.—American Homestead, A New Wearsen Vane.—The old weathercock has two essential fanlts; it indicates a direction when there is a dead calm. It gives no means of learning the force of the wind; while it fuils to show the true course of the same, by exhibiting merely its horizontal component. M. Tany proposes the arrangement to be attuched to the ordinary lightning rod. Just above u suitable shonlder on the latter is placed a copper ring, grooved and made into a pniley easily rotated in u horizontal plane. Around this passee a knotted cord, the ends of which are secured to the extremities of a short stick or metal rod, to which is secured a simple streamer. Thns constructed the vane indicates ucalm by falling vertically, and besides shows the strength of the wind by being hiown ont more or less from the lightning rod. As is evident, it is capable of motion in every direction, so that ifthere exist in the wind an upward tending vertical component, the same will be shown. Tannino Lasm-SkINS WITH THE Woon on,— Wash the pelts in warm water, and remove ull floshy matter from the inner surface; then cleun the wool with yellow soap, and rinse the ay thoroughly out. When this is doue apply to the flesh side the following mixture for each pelt: Common salt and alum, one qnarter of & pound of eaeh, and half an onnce of borax, dissolved in a qnartof warm water; add to this enough rye-meul to make a thick paste, and spread tho mixture ou the flesh side of the pelt. Fold the skin lengthwise and let it remain two weeks in an uiry snd ehady place, thou remove the paste from tho eurface; wash aud dry. When nearly dry scrape the fissh side with u knife, working tho pelt until it becomes thoroughly soft. Coverino ror Steam Prees.—Loose paper is wrapped round the pipee and painted with thin syrup; anu thisis paiuted a mixtnre of 4 bushels of loam, 6 bushels of sand or coke-dust, 3 pails of syrup, and 30 pounde of grsphite; the mass is put on 20 mm, thick, and painted with oil or tar, : . New Way of Coloring Metals. It is announced that inetals may be colored qnickly und cheaply by forming on their surface u coating of a thin film of a sniphide. So for instance brass articles may be tbus in five minutes coated with auy color varying from gold to copper red, then to carmine, dark red, and from light anilin blue to a blue white, like sulphide of lead, and at last u reddish white, uccording to the thicknoss of the cout, which depends on the length of time the metal remaiusin the solution nsed. The colors possc ss the most beautifnl Inster, and if the articles to be colored have been previously thoroughly cleaned by ineane of acids and alkalics, they adhere so firmly that they may be operated upon by the polishiug steel. To prepare the solution dissolve 144 ounces of hyposu!phite of soda in 1 pound of water, and add 124 ounces of ucetate of lead dissulved in 14 pound of water, When this clear solution is heated to 190° to 2109 Fahr., it decomposes slowly and precipitates snlphite of lead iu hruwn flocks. If metal is now present, a part nf the sulphite of lead is deposited thereon, and, according to the thickness of the deposited sulphite of lead, the ahove-mentioned beautiful luster colors are produced. To produce an even coloring, the articles mnst he evenly heated. Iron treated with this solutiou takes a steel-blne color; zioe, a brown color; in the case of copper objects, the first gold color does not appear; lend and and zine are entirely indifferent, If instead of the acetate of lead an eqnal weight of sulphuric acid is added to the hyposulphite of soda, and the process carried oa as before, the brass is covered with a very beautiful red, which is followed by u green, (which is not iu the firstmentioned scale of colors,) and changes finally to a splendid brown with green and red irislitter. This last is u very durable coating, and may find special attention in mannfactures. Very beantiful marbleized desigus can be produced by nsing a lead solution thickened with gum tragacanth, on biass whicb has been heated to 210° Fabr., and is afterward treated by the nsual solution of snlphide oflead. The solution may be used several times. Perstn AND THE DioEstion oF Fisrin wiraour Peprsin.—Experiments performed in the physiological laboratory of Heidelberg by Gustave Wolffhiigel, under Kitbne’e direotion, have led to the results essontially differing from those of Von Wittich and previous experimenters. 1. Wolffbiigel finds that pepsin is not diffasable. 2. That the pyloric glands pxoduce no pepsin. 3. That beth hydrochloric and citric acids in solution, contsining 0-4 per cent. at a temperature of 60° C., are capuble of dissolving boiled fibrin, though somewhut slowly, and of couverting it iuto peptone. 4. This power of forming peptone is perceptible in both acids at a temperature of 40° C. (104° F,) Thongh the action of nitric acid is decidedly slower, on this acconnt nitric acid is to be preferred to hydrochloric in experiments on the presence and action of pepsin. Bracounot described a sngar obtained from mushrooms which was found to be manuite. A. Muntz examined seyeral different species, aud in some no mannite was found, but a sugar which was undonistedly trehalose or mycose; some contained both sugars. Goon Hearrtl. Catching Cold. Catching cold is ‘‘as easy as lying,’’ but to explain the pathology thereof is by no means so readily done. In fact, until the recont researches of Dr. Rosenthal, whose work on the subject is attracting mnch notice in Europe, ulmost nothing was known about it except the mere fact that the ailments popniarly ascribed to “cold” are liable to occnr after the body, or some part of it, has been snddenly chilled, that is, cooled below the normal temperature. There sre two fuctors concerned in this chilliug precess; the nature of the external medium— such as air or water—in contact with the body; and the condition of the blood-vessels. Dry air has very little power to abstract heat, if it be still; but a slight wind, from the constant contact of fresh particles of cold uir on the snrfaco of the body, soon carries off its heat. If there is much moisture combined, the chilling effect reaches its maximum, ITxperience has shown that itis not so much the pbsolute lowness of temperature which gives rise to colds, as sndden changes from a higher toa lower. The reason of this was not understood until Dr. Rosenthal explained it. When the surface of u healthy animal is exposed to cold the cutaneons vessele contract, and by thns confining the blood to the interior of the body, prevent its cooling, and preserve the temporature of the vital organs, uuless tho application of cold bo continued for a considerable time. Thisis not the case, however, when the animal has been previously exposed to warmth. Tho cntaneous vessels become paralyzed by the heat, and remain dilated even after the cold has heen applied. Whe blood is thus cxposed over u large surface und hecomes rapidly cooled, even though the tomperature fo the snrronnding medium is not very low. In Rosenthal’s experiments, animals were kept from 97 to 104 degrees F. The temperature of tbe animals themselves quickly rose during their confinement to 111 or 113 degrees. After their removal it not only sank to the normal temperature, hnt even below it, so that an animal which was from 108 to 111 degrees in the warming apparatus fell to 96.8 decrees, and remained at that for sevoral days, although the room in which it was kept wus moderu’ely warm. Confinement iu a close office, hot theater, or crowded ball-room, will have a similar effect on man, From euch places, people pass oat iuto the cool, open air,or sumetimes even purposely station themselves in a draught. The blood, which ls coursing through the dilated vessels of every part of the surface, is rapidly cooled, and, on its return to the internal organs, cools them much more quickly than it conld have dove had tho person simply heen exposed to cold witbout dilatation of the vessels by previous wsrmtb. Roscnthal lays mnoch stress on the great effect of sudden cooling in bringing on a cold, the sudden chunge in the temperature of tbe blood producing an irritating effect, and inducing intlamation in any weak orgaw ina way that a gradual alteration would not do, It would seem, however, that the alteration must he from a temperature above to one below the normal temperature of the blood, and not a mere reduction from one considerably above the normal to one at or near it. When much heated we may stand for a short time in a cool atmosphere with impnnity ; but if we stand long enough to produce a shiver, We 100 4 great risk of cutching cold. The fuct that it is moro dangerous to sit for along time in wet clothes, appcars to indicate that a considerable and more gradual cooling, such us may then occur will produce similar effects to a slight cooling suddenly effected by exposnre to acold draugbt after being in a chill, in cuusiug inflammatiors may be partly due to the effect of cold ou the tissnes themselves, and partly to the congestion which will occur in some parts when the blood is driven out of others by the contraction of their vessels. Rosenthul is inclined to uscribe the chief power to the former cause. Everybody knows the beneficial effect of cold baths, cold sponging, ete., in ‘‘hardening’’ persons, as it is termed, so that they are abla to face almost any weather and to endure sndden changes of temperature withont injury. Rosenthal considers that the frequent application of cold water or cool air increases the tone of tho cutsncous vessels, so that they do not become so much relaxed by heat us to he unable to contract witb sufficient force when necessary. The power of regulating the temperature is thus preserved, and the person prevented from catching cold.—Journal of Chemistry. Tue Txenapeutio Ust or Dnry Powpenep Buoop.—Dr. Do Pascale, of Nice, several years ago published some observations on the very heneficial effect of warm blood taken the moment when extracted from the calf or ox, killed for general domestic use. He described at that time several cases of hsmoptysis, in which a complete cure had been affected by this treatment. In a paper recently published, he states that, finding among his English and American patients at Nice an nnconquerable Tepngnance to such a remedy, he wasled to adopt the plan of giving the blood in the form of dry powder. This is merely the revival of a practice which wasin vogue many years ago, and which has occasionslly beeu tia in this country. The blood of the ox, after being dried in a water-hath, is rednced to a very fine powder, and grated through a sieve. Dry blood can be taken for any length of time, beiug almost tasteless, and no repugnance is likely to be felt, as is often the case with raw meat. It can betaken as any common powder, mixed with sonps, milk, marmalsde, or chocolate, or enclosed in a wafer. In some cases, where even the name of blood might have offended the patient, Dr. De Pascale has given it, mixed with a small quantity of pepsin, under the name of ‘’nntritive powders.’’ The quantity he prescrihes has varied according to the age, sex, or the state of health and digestive power of the patient. In general, he begins with thirty grains, which is increased according to cirenmstances; but the qnantity must be left to the discretion of the physician. Hint For Prosecrors or Towns AND STREETS. ~—It is worthy of remark that the arranging of the streets according to the cardinal points involves a sanitsry objectiou of no mean import. No fact is better established tban the necessity of snnlight to health, and no constitution can long endure, without ill effects, the total privation of its health-giviug power. Every house on the South side of a street rnnuing Hast and West mnst have its front rooms, which are generally its living rooms, entirely deprived of the sun during the summer. This fact, coupled with that of the iudoor life of American, and particularly Western women, is enough to account for a very larga share of the nervous debility which so generally prevails. If the rectangular syetem must be adhered to in city arrangement, it would be far hetter that the lines of streets shonld be Northweet and Southeast, and the cross streets ut right angles with them, than as now dispesed; in this case the rooms in front or the rear of a honse enjoy at least sunshine in the morning or evening. A strong proof that sunshine ie wholesome is found in the fact that during epidemics people oocupying rooms not exposed to snnlight are comparatively mnoh worse off than those who enjoy that blessing.— Manufacturer and Builder. Domestic Economy. Food. Though man does not live by bread alone, the brend portion of bis sustenance is of very great importance. Ignoring the hody is as fruitful in mischievous results as living for it alone. Body and soul are so dependent on each other that what affects ove affects the other, and the more fiuely organized the body and the soul of any person may be, the greater must be his care to keop the two iu perfect harmony. It makes a world of differonce what one eats. No class of people aro so particular ahout their food, the quality, the mode of cooking, nnd the manner of serving, as those who live by their brains. They know thst the human animal who wonld keep in the highest working order mnst be us carefully groomed, as nicely fed, as perfectly appointed as Goldsmith Maid or Dexter, and they lay their plans aceordingly. The cooking s potato, the compounding a cup of coffee, the broiling a stake, the making and baking a loaf of bread, are to them of vital importance, as indeed, they should be to everybody. A great muny people never ap to enquire what particular diet is hest for them, but following the injnnetions of St. Paul, ina sense uever intended by him, eat what is set before them, asking no questions for conscience sake or any other suke, If “hog and hominy”’ is the standard dish, they live on that; if hot soda biscuit and steak fried in lurd are provided, that mnst reénforce their strength and content their appetites. Itis amelancholy fact that horses and cows and dogs are more intelligent feeders thun most human beings, and by natural conseqnence, they rarely havo dyspepsia, gont or humors, If men and women would be governed in their diet by reason aa rigidly as brutes are hy instinct, u large portion of the ills that flesh is heir to would uever be heard of. How muny who read this column nnderstand the chemistry of food, and know just what they must eat to mske them warm, what food builds up bone and sinew, and mnscle, and what will best supply the nervous waste? How many understand the effect of diet on the temper and disposition of the mind, and avoid whatever will makethem irritable, stupid and melancholy? How mauy motbers regulate the food of their children with reference to these results, and by so doing secure the tranquillity of their entire honseholds? How many students are there, who, alive to the importance of proper diet, eat only food ‘‘convenient for them ?”’ The object of this article is not so much to impart kuowledge as to uwaken in other minds u desire to investigate this subject in its varions beariogs. There are books fall of information of all sorts respecting the chemistry of food, the composition of bone, and muscle, and brain, and blood, which, if generally nnderstood, and their suggestions carried ont, would go far to’ banish sickness, and crime, and want.—N. Y. Tribune. WATER IN THE Hovse.—A prominent writer says: ‘’Let nobody be deterred from bringing water in the house by any fears of failnre and perplexity. You might just as well stop the cirenlation of blood in the body because it is subject to derangement, as to refuse the ciroalation of water in the house because now and the a pipe overflows, and yonr frescoes’ are ruined, Good workmen will prevent any such accident, but if they cannot, give np your frescoes; do not give up your life blood. When I see the farmhonses, the dairies, the kitchen, whose only source of supply is the well in the yard, or the hogshead at the back door, how life would be lengthened and sweetened if all this heavy, and hard and slow water-bringiug could be supplanted by a turn of ascrew, I wonder that we do not manage to introduce it, somehow, into our msrriage contracts. What an increase of vital forea would ensue; whata diminished demand for divorce; what a strengthening and upbuilding of the family bond, if a girl should refnse to murry until there was an inexhaustible supply of wuter, at leastin the kitchen. A house without water works ought to be considered as incomplete as a house without doors, and as incomplete in the country as in the city.” How ro Coox Fnesu Fisn.—After fresh fish have been dressed well and washed, roll them iuIndian meal, (after being sifted of course,) pnt them iuto a hot spider where there has been a large spoonful or two of lard melted, Sprinkle over some salt, then pnt the spider into the well heated oven und let them crisp over. Tuke them from the oven, lay them on a deep plate, turn all the fat out of the spider; (it will only be found fit for soap grease). Now put one quarter of a pound of butter in the spider, put it over the fire, and when it ie all melted, add one half tea cup of etrong vinegar to the melted hutter, stir quickly, and ponr it over the fish and serveimmediately. I find but very few people hnt what think thiemethod of cooking fresh fish, ie very superior to the more common way of cooking it withont adding the vinegar gravy.—Ohio Farmer.

January 24, 1874.] MINING AND SCIENTIFIC PRESS. 55 User: INpoRMATION. Why do Paints Dry ? It was proved long ugo, that linseed oil, when exposed to the air, becamo covered with a hard crast, and that this crast is produccd by the ubsorption of oxygen. Pulnt mado from oil and coloring matter alone does not dry because it narts with any thing or because it gives off any vapor, bnt becauso It hccomea bard hy the action of the atmosphere. It is stated in a recent work on paints thut oil does not form even the basin ofa paint. This is more technical than judicions. Oil alone, if laid on in thin, successive coats, hecomes very hard and forms a durable and impervious varnish, which protects the wood beneuth almost as well as paint would do, at least so far as nioistare und sir are concerued. Against the sun's raya, however, itis a poor defense. But as it hos been found impossible to apply a eufficient coat of this varnish inany thing like u reasonable time, the oil has in general heen mixed with various colored powders or pigments, which thicken it and thus enshle us to lay on u heavier coat. Many of these pigments have no action ou the oil, and it is always best that they shonld have no action. Compnunds of lead, which are known to form chemical compounds with the oil, are amongst the very poorest paints, White lead is confessedly one of the least efficient of all our preservative agents, the authority referred to to the oontrary notwithstanding. When paint ia applied to a fresb surfnco of wood, it often appears to dry in a short time. In this case, however, it will be found that tbe aint has not really dried, hut thut tho oil has eer absorbed by the wood; and in tbis case the pigment is often left in tbe form of a friable powder, loosely adberent to the surface to which it was applied. It rubs off very easily. This occurs to uless extent with white lead tban with uny other paint, eimply heeause the lead combines witb the oil and holdsit on the surface, thus preventing its sinking in. We are inclined to regard this feature as one which confers no advantages upou white lead. It is prnbably better for the wood that as mucb oil as possihile should soak into it, and it is no grest disadvantage tbat the paint of the first coat should not adbere strongly. Where economy is un objeet, the absorption of the oil is prevented by first applying a coat of cheap sizing. The size fills np the pores of the wood, and prevents the sinking in of the oil. For in-door work, this answers very well, bnt for out-door purposes it is objectionable, But all paints do not dry in the manner that we have mentioned. For in-door work, where itis desirable that the paint should dry rapidly and have a dead or non-reflecting surface, paint is generally mixed with turpentine. This is a volatile oil, which passes off rspidly when exposed to the air, and thns leaves the paint behind as a thin crust. This ability of the paint to resist atmospheric influences is tbereby lessened; and this, for in-door work, is a mutter of no conseqnence. It wonldbe wrong, perhaps, to say that the oil of turpentine passes off entirely by evaporation, as a small portion probably becomes oxidated and remaing behind. The amonnt so retained is, however, very small.—American Homestead, A New Wearsen Vane.—The old weathercock has two essential fanlts; it indicates a direction when there is a dead calm. It gives no means of learning the force of the wind; while it fuils to show the true course of the same, by exhibiting merely its horizontal component. M. Tany proposes the arrangement to be attuched to the ordinary lightning rod. Just above u suitable shonlder on the latter is placed a copper ring, grooved and made into a pniley easily rotated in u horizontal plane. Around this passee a knotted cord, the ends of which are secured to the extremities of a short stick or metal rod, to which is secured a simple streamer. Thns constructed the vane indicates ucalm by falling vertically, and besides shows the strength of the wind by being hiown ont more or less from the lightning rod. As is evident, it is capable of motion in every direction, so that ifthere exist in the wind an upward tending vertical component, the same will be shown. Tannino Lasm-SkINS WITH THE Woon on,— Wash the pelts in warm water, and remove ull floshy matter from the inner surface; then cleun the wool with yellow soap, and rinse the ay thoroughly out. When this is doue apply to the flesh side the following mixture for each pelt: Common salt and alum, one qnarter of & pound of eaeh, and half an onnce of borax, dissolved in a qnartof warm water; add to this enough rye-meul to make a thick paste, and spread tho mixture ou the flesh side of the pelt. Fold the skin lengthwise and let it remain two weeks in an uiry snd ehady place, thou remove the paste from tho eurface; wash aud dry. When nearly dry scrape the fissh side with u knife, working tho pelt until it becomes thoroughly soft. Coverino ror Steam Prees.—Loose paper is wrapped round the pipee and painted with thin syrup; anu thisis paiuted a mixtnre of 4 bushels of loam, 6 bushels of sand or coke-dust, 3 pails of syrup, and 30 pounde of grsphite; the mass is put on 20 mm, thick, and painted with oil or tar, : . New Way of Coloring Metals. It is announced that inetals may be colored qnickly und cheaply by forming on their surface u coating of a thin film of a sniphide. So for instance brass articles may be tbus in five minutes coated with auy color varying from gold to copper red, then to carmine, dark red, and from light anilin blue to a blue white, like sulphide of lead, and at last u reddish white, uccording to the thicknoss of the cout, which depends on the length of time the metal remaiusin the solution nsed. The colors possc ss the most beautifnl Inster, and if the articles to be colored have been previously thoroughly cleaned by ineane of acids and alkalics, they adhere so firmly that they may be operated upon by the polishiug steel. To prepare the solution dissolve 144 ounces of hyposu!phite of soda in 1 pound of water, and add 124 ounces of ucetate of lead dissulved in 14 pound of water, When this clear solution is heated to 190° to 2109 Fahr., it decomposes slowly and precipitates snlphite of lead iu hruwn flocks. If metal is now present, a part nf the sulphite of lead is deposited thereon, and, according to the thickness of the deposited sulphite of lead, the ahove-mentioned beautiful luster colors are produced. To produce an even coloring, the articles mnst he evenly heated. Iron treated with this solutiou takes a steel-blne color; zioe, a brown color; in the case of copper objects, the first gold color does not appear; lend and and zine are entirely indifferent, If instead of the acetate of lead an eqnal weight of sulphuric acid is added to the hyposulphite of soda, and the process carried oa as before, the brass is covered with a very beautiful red, which is followed by u green, (which is not iu the firstmentioned scale of colors,) and changes finally to a splendid brown with green and red irislitter. This last is u very durable coating, and may find special attention in mannfactures. Very beantiful marbleized desigus can be produced by nsing a lead solution thickened with gum tragacanth, on biass whicb has been heated to 210° Fabr., and is afterward treated by the nsual solution of snlphide oflead. The solution may be used several times. Perstn AND THE DioEstion oF Fisrin wiraour Peprsin.—Experiments performed in the physiological laboratory of Heidelberg by Gustave Wolffhiigel, under Kitbne’e direotion, have led to the results essontially differing from those of Von Wittich and previous experimenters. 1. Wolffbiigel finds that pepsin is not diffasable. 2. That the pyloric glands pxoduce no pepsin. 3. That beth hydrochloric and citric acids in solution, contsining 0-4 per cent. at a temperature of 60° C., are capuble of dissolving boiled fibrin, though somewhut slowly, and of couverting it iuto peptone. 4. This power of forming peptone is perceptible in both acids at a temperature of 40° C. (104° F,) Thongh the action of nitric acid is decidedly slower, on this acconnt nitric acid is to be preferred to hydrochloric in experiments on the presence and action of pepsin. Bracounot described a sngar obtained from mushrooms which was found to be manuite. A. Muntz examined seyeral different species, aud in some no mannite was found, but a sugar which was undonistedly trehalose or mycose; some contained both sugars. Goon Hearrtl. Catching Cold. Catching cold is ‘‘as easy as lying,’’ but to explain the pathology thereof is by no means so readily done. In fact, until the recont researches of Dr. Rosenthal, whose work on the subject is attracting mnch notice in Europe, ulmost nothing was known about it except the mere fact that the ailments popniarly ascribed to “cold” are liable to occnr after the body, or some part of it, has been snddenly chilled, that is, cooled below the normal temperature. There sre two fuctors concerned in this chilliug precess; the nature of the external medium— such as air or water—in contact with the body; and the condition of the blood-vessels. Dry air has very little power to abstract heat, if it be still; but a slight wind, from the constant contact of fresh particles of cold uir on the snrfaco of the body, soon carries off its heat. If there is much moisture combined, the chilling effect reaches its maximum, ITxperience has shown that itis not so much the pbsolute lowness of temperature which gives rise to colds, as sndden changes from a higher toa lower. The reason of this was not understood until Dr. Rosenthal explained it. When the surface of u healthy animal is exposed to cold the cutaneons vessele contract, and by thns confining the blood to the interior of the body, prevent its cooling, and preserve the temporature of the vital organs, uuless tho application of cold bo continued for a considerable time. Thisis not the case, however, when the animal has been previously exposed to warmth. Tho cntaneous vessels become paralyzed by the heat, and remain dilated even after the cold has heen applied. Whe blood is thus cxposed over u large surface und hecomes rapidly cooled, even though the tomperature fo the snrronnding medium is not very low. In Rosenthal’s experiments, animals were kept from 97 to 104 degrees F. The temperature of tbe animals themselves quickly rose during their confinement to 111 or 113 degrees. After their removal it not only sank to the normal temperature, hnt even below it, so that an animal which was from 108 to 111 degrees in the warming apparatus fell to 96.8 decrees, and remained at that for sevoral days, although the room in which it was kept wus moderu’ely warm. Confinement iu a close office, hot theater, or

crowded ball-room, will have a similar effect on man, From euch places, people pass oat iuto the cool, open air,or sumetimes even purposely station themselves in a draught. The blood, which ls coursing through the dilated vessels of every part of the surface, is rapidly cooled, and, on its return to the internal organs, cools them much more quickly than it conld have dove had tho person simply heen exposed to cold witbout dilatation of the vessels by previous wsrmtb. Roscnthal lays mnoch stress on the great effect of sudden cooling in bringing on a cold, the sudden chunge in the temperature of tbe blood producing an irritating effect, and inducing intlamation in any weak orgaw ina way that a gradual alteration would not do, It would seem, however, that the alteration must he from a temperature above to one below the normal temperature of the blood, and not a mere reduction from one considerably above the normal to one at or near it. When much heated we may stand for a short time in a cool atmosphere with impnnity ; but if we stand long enough to produce a shiver, We 100 4 great risk of cutching cold. The fuct that it is moro dangerous to sit for along time in wet clothes, appcars to indicate that a considerable and more gradual cooling, such us may then occur will produce similar effects to a slight cooling suddenly effected by exposnre to acold draugbt after being in a chill, in cuusiug inflammatiors may be partly due to the effect of cold ou the tissnes themselves, and partly to the congestion which will occur in some parts when the blood is driven out of others by the contraction of their vessels. Rosenthul is inclined to uscribe the chief power to the former cause. Everybody knows the beneficial effect of cold baths, cold sponging, ete., in ‘‘hardening’’ persons, as it is termed, so that they are abla to face almost any weather and to endure sndden changes of temperature withont injury. Rosenthal considers that the frequent application of cold water or cool air increases the tone of tho cutsncous vessels, so that they do not become so much relaxed by heat us to he unable to contract witb sufficient force when necessary. The power of regulating the temperature is thus preserved, and the person prevented from catching cold.—Journal of Chemistry. Tue Txenapeutio Ust or Dnry Powpenep Buoop.—Dr. Do Pascale, of Nice, several years ago published some observations on the very heneficial effect of warm blood taken the moment when extracted from the calf or ox, killed for general domestic use. He described at that time several cases of hsmoptysis, in which a complete cure had been affected by this treatment. In a paper recently published, he states that, finding among his English and American patients at Nice an nnconquerable Tepngnance to such a remedy, he wasled to adopt the plan of giving the blood in the form of dry powder. This is merely the revival of a practice which wasin vogue many years ago, and which has occasionslly beeu tia in this country. The blood of the ox, after being dried in a water-hath, is rednced to a very fine powder, and grated through a sieve. Dry blood can be taken for any length of time, beiug almost tasteless, and no repugnance is likely to be felt, as is often the case with raw meat. It can betaken as any common powder, mixed with sonps, milk, marmalsde, or chocolate, or enclosed in a wafer. In some cases, where even the name of blood might have offended the patient, Dr. De Pascale has given it, mixed with a small quantity of pepsin, under the name of ‘’nntritive powders.’’ The quantity he prescrihes has varied according to the age, sex, or the state of health and digestive power of the patient. In general, he begins with thirty grains, which is increased according to cirenmstances; but the qnantity must be left to the discretion of the physician. Hint For Prosecrors or Towns AND STREETS. ~—It is worthy of remark that the arranging of the streets according to the cardinal points involves a sanitsry objectiou of no mean import. No fact is better established tban the necessity of snnlight to health, and no constitution can long endure, without ill effects, the total privation of its health-giviug power. Every house on the South side of a street rnnuing Hast and West mnst have its front rooms, which are generally its living rooms, entirely deprived of the sun during the summer. This fact, coupled with that of the iudoor life of American, and particularly Western women, is enough to account for a very larga share of the nervous debility which so generally prevails. If the rectangular syetem must be adhered to in city arrangement, it would be far hetter that the lines of streets shonld be Northweet and Southeast, and the cross streets ut right angles with them, than as now dispesed; in this case the rooms in front or the rear of a honse enjoy at least sunshine in the morning or evening. A strong proof that sunshine ie wholesome is found in the fact that during epidemics people oocupying rooms not exposed to snnlight are comparatively mnoh worse off than those who enjoy that blessing.— Manufacturer and Builder. Domestic Economy. Food. Though man does not live by bread alone, the brend portion of bis sustenance is of very great importance. Ignoring the hody is as fruitful in mischievous results as living for it alone. Body and soul are so dependent on each other that what affects ove affects the other, and the more fiuely organized the body and the soul of any person may be, the greater must be his care to keop the two iu perfect harmony. It makes a world of differonce what one eats. No class of people aro so particular ahout their food, the quality, the mode of cooking, nnd the manner of serving, as those who live by their brains. They know thst the human animal who wonld keep in the highest working order mnst be us carefully groomed, as nicely fed, as perfectly appointed as Goldsmith Maid or Dexter, and they lay their plans aceordingly. The cooking s potato, the compounding a cup of coffee, the broiling a stake, the making and baking a loaf of bread, are to them of vital importance, as indeed, they should be to everybody. A great muny people never ap to enquire what particular diet is hest for them, but following the injnnetions of St. Paul, ina sense uever intended by him, eat what is set before them, asking no questions for conscience sake or any other suke, If “hog and hominy”’ is the standard dish, they live on that; if hot soda biscuit and steak fried in lurd are provided, that mnst reénforce their strength and content their appetites. Itis amelancholy fact that horses and cows and dogs are more intelligent feeders thun most human beings, and by natural conseqnence, they rarely havo dyspepsia, gont or humors, If men and women would be governed in their diet by reason aa rigidly as brutes are hy instinct, u large portion of the ills that flesh is heir to would uever be heard of. How muny who read this column nnderstand the chemistry of food, and know just what they must eat to mske them warm, what food builds up bone and sinew, and mnscle, and what will best supply the nervous waste? How many understand the effect of diet on the temper and disposition of the mind, and avoid whatever will makethem irritable, stupid and melancholy? How mauy motbers regulate the food of their children with reference to these results, and by so doing secure the tranquillity of their entire honseholds? How many students are there, who, alive to the importance of proper diet, eat only food ‘‘convenient for them ?”’ The object of this article is not so much to impart kuowledge as to uwaken in other minds u desire to investigate this subject in its varions beariogs. There are books fall of information of all sorts respecting the chemistry of food, the composition of bone, and muscle, and brain, and blood, which, if generally nnderstood, and their suggestions carried ont, would go far to’ banish sickness, and crime, and want.—N. Y. Tribune. WATER IN THE Hovse.—A prominent writer says: ‘’Let nobody be deterred from bringing water in the house by any fears of failnre and perplexity. You might just as well stop the cirenlation of blood in the body because it is subject to derangement, as to refuse the ciroalation of water in the house because now and the a pipe overflows, and yonr frescoes’ are ruined, Good workmen will prevent any such accident, but if they cannot, give np your frescoes; do not give up your life blood. When I see the farmhonses, the dairies, the kitchen, whose only source of supply is the well in the yard, or the hogshead at the back door, how life would be lengthened and sweetened if all this heavy, and hard and slow water-bringiug could be supplanted by a turn of ascrew, I wonder that we do not manage to introduce it, somehow, into our msrriage contracts. What an increase of vital forea would ensue; whata diminished demand for divorce; what a strengthening and upbuilding of the family bond, if a girl should refnse to murry until there was an inexhaustible supply of wuter, at leastin the kitchen. A house without water works ought to be considered as incomplete as a house without doors, and as incomplete in the country as in the city.” How ro Coox Fnesu Fisn.—After fresh fish have been dressed well and washed, roll them iuIndian meal, (after being sifted of course,) pnt them iuto a hot spider where there has been a large spoonful or two of lard melted, Sprinkle over some salt, then pnt the spider into the well heated oven und let them crisp over. Tuke them from the oven, lay them on a deep plate, turn all the fat out of the spider; (it will only be found fit for soap grease). Now put one quarter of a pound of butter in the spider, put it over the fire, and when it ie all melted, add one half tea cup of etrong vinegar to the melted hutter, stir quickly, and ponr it over the fish and serveimmediately. I find but very few people hnt what think thiemethod of cooking fresh fish, ie very superior to the more common way of cooking it withont adding the vinegar gravy.—Ohio Farmer.