WASHING b.u.t.tER.

"When the operation is properly conducted, the b.u.t.ter, after some time, suddenly forms, and is to be carefully collected and separated from the b.u.t.termilk. But in doing this, it is not sufficient merely to pour off the milk, or withdraw the b.u.t.ter from it; because a certain portion of the caseous and serous parts of the milk still remains in the interstices of the b.u.t.ter, and must be detached from it by washing, if we would obtain it pure. In washing b.u.t.ter, some think it sufficient to press the ma.s.s gently between the hands; others press it strongly and frequently, repeating the washings till the water comes off quite clear.

The first method is preferable when the b.u.t.ter is made daily, for immediate use, from new milk or cream; because the portions of such adhering to it, or mixed with it, contribute to produce the sweet agreeable flavor which distinguishes new cream. But when our object is to prepare b.u.t.ter for keeping, we cannot repeat the washings too often, since the presence of a small quant.i.ty of milk in it will, in less than twelve hours after churning, cause it sensibly to lose its good qualities.

"The process of washing b.u.t.ter is usually nothing more than throwing it into an earthen vessel of clear cool water, working it to and fro with the hands, and changing the water until it comes off clear. A much preferable method, however, and that which we believe is now always practised by those who best understand the business, is to use two broad pieces of wood, instead of the hands. This is to be preferred, not only on account of its apparently greater cleanliness, but also because it is of decided advantage to the quality of the b.u.t.ter. To this the warmth of the hand gives always, more or less, a greasy appearance. The influence of the heat of the hand is greater than might at first have been suspected. It has always been remarked, that a person who has naturally a warm hand never makes good b.u.t.ter."

COLORING b.u.t.tER.

As b.u.t.ter made in winter is generally pale or white, and its richness, at the same time, inferior to that which is made during the summer months, the idea of excellence has been a.s.sociated with the yellow color. Means are therefore employed, by those who prepare and sell b.u.t.ter, to impart to it the yellow color where that is naturally wanting. The substances mostly employed in England and Scotland are the root of the carrot and the flowers of the marigold. The juice of either of these is expressed and pa.s.sed through a linen cloth. A small quant.i.ty of it (and the proportion of it necessary is soon learned by experience) is diluted with a little cream, and this mixture is added to the rest of the cream when it enters the churn. So little of this coloring matter unites with the b.u.t.ter, that it never communicates to it any peculiar taste.

DESCRIPTION OF THE ORGANS OF DIGESTION IN CATTLE.

_Oesophagus_, or _Gullet_.--This tube extends from the mouth to the stomach, and is the medium through which the food is conveyed to the latter organ. This tube is furnished with spiral muscles, which run in different directions. By this arrangement, the food ascends or descends at the will of the animal. The inner coat of the gullet is a continuation of the same membrane that lines the mouth, nostrils, &c.

The gullet pa.s.ses down the neck, inclining to the left side of the windpipe, until it reaches the diaphragm, through a perforation of which it pa.s.ses, and finally terminates in the stomach. The food, having undergone a slight mastication by the action of the teeth, is formed into a pellet, and, being both moistened and lubricated with saliva, pa.s.ses down the gullet, by the action of the muscles, and falls immediately into the paunch, or rumen; here the food undergoes a process of maceration, or trituration. The food, after remaining in this portion of the stomach a short time, and being submitted to the united action of heat and moisture, pa.s.ses into another division of the stomach, called _reticulum_, the inner surface of which abounds in cells: at the bottom, and indeed in all parts of them there are glands, which secrete from the blood the gastric fluids. This stomach possesses a property similar to that of the bladder, viz., that of contracting upon its contents. In the act of contracting, it squeezes out a portion of the partly masticated food and fluids; the former comes within the spiral muscles, is embraced by them, and thus ascends the gullet, and pa.s.ses into the mouth for remastication. The soft and fluid parts continue on to the many plus and true digestive stomach. The second stomach again receives a portion from the paunch, and the process is continued.

Rumination and digestion, however, are mechanico-vital actions, and can only be properly performed when the animal is in a healthy state.

Now, a portion of the food, we just observed, had ascended the gullet by the aid of spiral muscles, and entered the mouth; it is again submitted to the action of the grinders, and a fresh supply of saliva; it is at length swallowed a second time, and goes through the same routine as that just described, pa.s.sing into the manyplus or manifolds, as it is termed.

The manyplus abounds internally in a number of leaves, called laminae.

Some of these are attached to the upper and lower portion of the division, and also float loose, and penetrate into the oesophagian ca.n.a.l. The laminae have numerous projections on their surface, resembling the papillae to be found on the tongue. The action of this stomach is one of alternate contraction and expansion: it secretes, however, like the other compartments of the stomach, its due share of gastric fluids, with a view not only of softening its contents, but for the purpose of defending its own surface against friction. The mechanical action of the stomach is communicated to it partly by the motion of the diaphragm, and its own muscular arrangement. It will readily be perceived, that by this joint action the food is submitted to a sort of grinding process. Hence any over-distention of the viscera, from either food or gas, will embarra.s.s and prevent the free and full play of this organ. The papillae, or prominences, present a rough and sufficiently hard exterior to grind down the food, unless it shall have escaped the reticulum in too fibrous a form: foxgra.s.s, cornstalks, and frosted turnips are very apt to make sad havoc in this and other parts of the stomach, owing to their unyielding nature; for the stomach, like other parts of the organization, suffers from over-exertion, and a corresponding debility ensues.

The fourth division of the stomach of the ox is called _abomasum_. It somewhat resembles the duodenum of the horse in its function, it being the true digestive stomach. It is studded with numerous nerves, blood-vessels, and small glands. It is a laboratory admirably fitted up by the Divine Artist, and is capable of carrying on the chemico-vital process as long as the animal lives, provided its healthy functions are not impaired. The glands alluded to secrete from the blood a powerful solvent, called the _gastric juice_, which is the agent in reducing the food to chyme and chyle. This, however, is accomplished by the united agency of the bile and pancreatic juice. Both these fluids are conveyed into the abomasum by means of small tubes or ca.n.a.ls. Secretions also take place from the inner membrane of the intestines, and, as the result of the united action of all these fluids, aided by the muscular motion just alluded to, which is also communicated to the intestines, a substance is formed called _chyle_, which is the most nutritious portion of the food, and has a milky appearance. The chyle is received into a set of very minute tubes, called _lacteals_, which are exceedingly numerous, and arise by open mouths from the inner surface of the abomasum and intestines. They receive the chyle; from thence it pa.s.ses into a receptacle, and finally into the thoracic duct. The thoracic duct opens into a vein leading directly to the heart; so that whatever portion of the chyle is not actually needed by the organism is thoroughly mixed with the general ma.s.s of blood. That portion of chyme which is not needed, or cannot be converted into chyle, descends into the intestines, and is finally carried out of the body by the r.e.c.t.u.m.

The manner in which the gastric fluids act on alimentary matter, is by solution and chemical action; for cornstalks and foxgra.s.s, that cannot be dissolved by ammonia or alcohol, yield readily to the solvent power of the gastric secretion. Bones and other hard substances are reduced to a pulpy ma.s.s in the stomach of a dog; while, at the same time, many bodies of delicate texture remain in the stomach, and ultimately are ejected, without being affected by the gastric fluids. This different action on different subjects is a.n.a.logous to the operation of chemical affinity, and corroborates the theory that digestion is effected by solution and chemical action.

_The Spleen_, or _Milt_, is an oblong, dark-colored substance, having attachments to the paunch. It is composed of blood-vessels, nerves, and lymphatics, united by cellular structure. It appears to serve as a reservoir for the blood that may be designed for the secretions of bile in the liver. P. M. Roget says, "Any theory that a.s.signs a very important function to the spleen will be overturned by the fact, that in many animals the removal of this organ, far from being fatal, or interrupting, in any sensible manner, the continuance of the functions, seems to be borne with perfect impunity." Sir E. Home, Bichat, Leuret, La.s.saigne, and others, suppose that "the spleen serves as a receptacle for the superfluous quant.i.ty of fluid taken into the stomach."

_The Liver_ is a dense gland, of a lobulated structure, situated below the diaphragm, or "skirt." It is supplied, like other organs, with arterial blood, by vessels, called _hepatic_ arteries, which are sent off from the great aorta. It receives also a large amount of venous blood, which is distributed through its substance by a separate set of vessels, derived from the venous system. The veins which receive the blood that has circulated in the usual manner unite together into a large trunk, called vena portae, (gate vein,) and this vein, on entering the liver, ramifies like an artery, and ultimately terminates in the branches of the hepatic veins, which transmit the blood, in the ordinary course of circulation, to the vena cava, (hollow vein.) Mr. Kiernan says, "The hepatic veins, together with the lobules which surround them, resemble, in their arrangement, the branches and leaves of a tree, the substance of the lobules being disposed around the minute branches of the veins like the parenchyma of a leaf around its fibres. The hepatic veins may be divided into two cla.s.ses, namely, those contained in lobules, and those contained in ca.n.a.ls formed by lobules. The first cla.s.s is composed of interlobular branches, one of which occupies the centre of each lobule, and receives the blood from a plexus formed in the lobule by the portal vein; and the second cla.s.s of hepatic veins is composed of all those vessels contained in ca.n.a.ls formed by the lobules, and including numerous small branches, as well as the large trunks terminating in the inferior cava. The external surface of every lobule is covered by an expansion of '_Glisson's capsule_,' by which it is connected to, as well as separated from, contiguous lobules, and in which branches of the hepatic duct, portal veins, and hepatic artery ramify. The ultimate branches of the hepatic artery terminate in the branches of the portal vein, where the blood they respectively contain is mixed together, and from which mixed blood the bile is secreted by the lobules, and conveyed away by the hepatic ducts. The remaining blood is returned to the heart by the hepatic veins, the beginnings of which occupy the centre of each lobule, and, when collected into trunks, pour their contents into the inferior cava. Hence the blood which has circulated through the liver, and has thereby lost its arterial character, is, in common with that which is returning from other parts, poured into the vena portae, and contributes its share in furnishing materials for the biliary secretion. The hepatic artery furnishes nutrition to the liver itself."

The bile, having been secreted, acc.u.mulates in the gall-bladder, where it is kept for future use. When the healthy action of the fourth stomach is interrupted, the bile is supposed to be reabsorbed,--it enters into the different tissues, producing yellowness of the eyes; the malady is then termed _yellows_, _jaundice_, &c. Sometimes the pa.s.sage of the bile is obstructed by calculi, or gall-stones; they have been found in great numbers in oxen.

_The Pancreas_ is composed of a number of lobules or glands; a small duct proceeds from each; they unite and form a common ca.n.a.l, which proceeds towards, and terminates in, the fourth stomach. The pancreatic juice appears to be exceedingly a.n.a.logous, both in its sensible properties and chemical composition, to the saliva.

"The recent researches of MM. Bouchardat, Sandras, Mialhe, Bareswil, and Bernard himself, have placed beyond a doubt the existence of a ferment, in some of the fluids which mix with the alimentary ma.s.s, destined to convert starchy matters into sugar. They have proved that the gastric juice has for its peculiar office the solution and digestion of azotized substances. There remained to be ascertained the real agent for the digestion of fatty matters; that is to say, the agent in the formation of chyle out of those substances.

"M. Bernard has proved that this remarkable office is performed by the pancreatic juice; he has demonstrated the fact by three conclusive proofs.

"1. The pancreatic juice, pure and recently formed, forms an emulsion with oils and fats with the greatest facility. This emulsion may be preserved for a long time, and the fatty substance soon undergoes a fermentation which separates its const.i.tuent acids.

"2. The chyle only begins to appear in the lacteals below that part of the intestinal tube where the pancreatic juice enters it to mix with the alimentary matters.

"3. In disorders of the pancreas, we find that the fatty matters, contained in the food, pa.s.s entire in the evacuations."

The above is an extract from the report of a body composed of several members of the French Academy of Sciences. "M. Bernard" (continues the report) "has exhibited to us the first of these experiments, and has furnished us with the means of repeating it with the several varieties of the gastric juice. We have not the slightest doubt on the subject. It is incontestable that fatty substances are converted into an emulsion by this juice, in a manner easy and persistent, and it is no less true that the saliva, the gastric juice, and the bile are dest.i.tute of this property.

"The second demonstration can be given in various modes; but the author has discovered, in the peculiar arrangement of the digestive apparatus of the rabbit, an unexceptional means of obtaining it with the greatest precision, and at will. The pancreatic juice enters the intestinal tube of this animal about fourteen inches below the point where the bile is poured in. Now, as long as the food is above the region where it mixes with the pancreatic juice, there appears to be no formation and separation of a milky chyle; nothing shows that the fatty matters are reduced to an emulsion. On the contrary, as soon as the pancreatic juice mixes with the alimentary matters, we observe the fat to be converted into an emulsion, and a milky chyle to fill the corresponding lacteals.

Nothing can give an idea of the result of these experiments, which have all the accuracy of a chemical operation performed in the laboratory, and all the beauty of the most perfect injection.

"We are not, therefore, surprised that divers pathological cases, hitherto imperfectly understood, should come to confirm the views of M.

Bernard, by proving that, in diseases of the pancreas, fatty matters have been observed to pa.s.s unchanged in the dejections.

"The committee cannot hesitate to conclude that the author has perfectly demonstrated his physiological propositions; that he has completed the general characters of the theory of digestion, and that he has made known the mode of formation of the fatty matter of the chyle, and the manner of the digestion of the fatty matters."

_The Kidneys._--Their office is, to secrete from the blood the useless or excrement.i.tious fluids in the form of urine. When the skin is obstructed, the secretion is augmented, and profuse perspiration lessens it. From a cavity in the centre of each kidney a ca.n.a.l or tube proceeds, by which the urine is conveyed into the bladder. These tubes are named _ureters_. As the ureters enter the bladder, they pa.s.s forward, a short distance between its coats; which effectually prevents the urine from taking a retrograde course. The urine is expelled by the muscular power which the bladder possesses of contracting upon its contents.

RESPIRATION AND STRUCTURE OF THE LUNGS.

The organs of respiration are the larynx, the trachea, or windpipe, bronchia, and the lungs.

The air is expelled from the lungs princ.i.p.ally by the action of the muscles of respiration; and when these relax, the lungs expand by virtue of their own elasticity. This may be exemplified by means of a sponge, which may be compressed into a small compa.s.s by the hand, but, upon opening the hand, the sponge returns to its natural size, and all its cavities become filled with air. The purification of the blood in the lungs is of vital importance, and indispensably necessary to the due performance of all the functions; for if they be in a diseased state,--either tuberculous, or having adhesions to the pleura, their function will be impaired; the blood will appear black; loaded with carbon; and the phlebotomizer will have the very best (worst) excuse for taking away a few quarts with a view of purifying the remainder! The trachea, or windpipe, after dividing into smaller branches, called _bronchia_, again subdivides into innumerable other branches, the extremities of which are composed of an infinite number of small cells, which, with the ramifications of veins, arteries, nerves, and connecting membranes, make up the whole ma.s.s or substance of the lungs. The internal surface of the windpipe, bronchia, and air-cells, is lined with a delicate membrane, highly organized with blood-vessels, &c. The whole is invested with a thin, transparent membrane--a continuation of that lining the chest, named _pleura_. It also covers the diaphragm, and, by a duplication of its folds, forms a separation between the lobes of the lungs.

CIRCULATION OF THE BLOOD.

The blood contains the elements for building up, supplying the waste of, and nourishing the whole animal economy. On making an examination of the blood with a microscope, it is found full of little red globules, which vary in their size and shape in different animals, and are more numerous in the warm than in the cold-blooded. Probably this arises from the fact that the latter absorb less oxygen than the former. When blood stands for a time after being drawn, it separates into two parts. One is called _serum_, and resembles the white of an egg; the other is the clot, or cra.s.samentum, and forms the red coagulum, or jelly-like substance. This is accompanied by whitish tough threads, called _fibrine_.

[Ill.u.s.tration: THE HEART VIEWED EXTERNALLY.

_a_, the left ventricle; _b_, the right ventricle; _c_, _e_, _f_, the aorta; _g_, _h_, _i_, the carotid and other arteries springing from the aorta; _k_, the pulmonary artery; _l_, branches of the pulmonary artery in the lungs; _m_, _m_, the pulmonary veins emptying into the left auricle; _n_, the right auricle; _o_, the ascending vena cava; _q_, the descending vena cava; _r_, the left auricle; _s_, the coronary vein and artery. (See _Circulation of the Blood_, on the opposite page.)]

When blood has been drawn from an animal, and it a.s.sumes a cupped or hollow form, if serum, or buffy coat, remains on its surface, it denotes an impoverished state; but if the whole, when coagulated, be of one uniform ma.s.s, it indicates a healthy state of that fluid. The blood of a young animal, provided it be in health, coagulates into a firm ma.s.s, while that of an old or debilitated one is generally less dense, and more easily separated. The power that propels the blood through the different blood-vessels is a mechanico-vital power, and is accomplished through the involuntary contractions and relaxations of the heart; from certain parts of which arteries arise, in other parts veins terminate.

(See Plate.)

The heart is invested with a strong membranous sac, called _pericardium_, which adheres to the tendinous centre of the diaphragm, and to the great vessels at its superior portion. The heart is lubricated by a serous fluid, secreted within the pericardium, for the purpose of guarding against friction. When an excess of fluid acc.u.mulates within the sac, it is termed dropsy of the heart. The heart is divided into four cavities, viz., two auricles, named from their resemblance to an ear, and two ventricles, (as seen at _a_, _b_,) forming the body. The left ventricle is smaller than the right, yet its walls are much thicker and stronger than those of the latter: it is from this part that the large trunk of the arteries proceed, called the _great aorta_. The right cavity, or ventricle, is the receptacle for blood returned by the venous structure after having gone the rounds of the circulation; the veins terminating, as they approach the heart, in a single vessel, called _vena cava_, (see plate, _o_, _q_, ascending and descending portion.) The auricle on the left side of the heart receives the blood that has been distributed through the lungs for purification.

Where the veins terminate in auricles, there are valves placed, to prevent the blood from returning. For example, the blood proceeds out of the heart along the aorta; the valve opens upwards; the blood also moves upwards, and raises the valve, and pa.s.ses through; the pressure from above effectually closes the pa.s.sage. The valves of the heart are composed of elastic cartilage, which admits of free motion. They sometimes, however, become ossified. The heart and its appendages are, like other parts of the system, subject to various diseases, which are frequently very little understood, yet often fatal. Now, the blood, having pa.s.sed through the veins and vena cava, flows into the right auricle; and this, when distended, contracts, and forces its contents into the right ventricle, which, contracting in its turn, propels the blood into the pulmonary arteries, whose numerous ramifications bring it in contact with the air-cells of the lungs. It then, being deprived of its carbon, a.s.sumes a crimson color. Having pa.s.sed through its proper vessels, it acc.u.mulates in the left auricle. This also contracts, and forces the blood through a valve into the left ventricle. This ventricle then contracts in its turn, and the blood pa.s.ses through another valve into the great aorta, to go the round of the circulation and return in the manner just described.

Many interesting experiments have been made to estimate the quant.i.ty of blood in an animal. "The weight of a dog," says Mr. Percival, "being ascertained to be seventy-nine pounds, a puncture was made with the lancet into the jugular vein, from which the blood was collected. The vein having ceased to bleed, the carotid artery of the same side was divided, but no blood came from it; in a few seconds afterwards, the animal was dead. The weight of the carca.s.s was now found to be seventy-three and a half pounds; consequently it had sustained a loss of five and a half pounds--precisely the measure of the blood drawn. It appears from this experiment, that an animal will lose about one fifteenth part of its weight of blood before it dies; though a less quant.i.ty may so far debilitate the vital powers, as to be, though less suddenly, equally fatal. In the human subject, the quant.i.ty of blood has been computed at about one eighth part of the weight of the body; and as such an opinion has been broached from the results of experiments on quadrupeds, we may fairly take that to be about the proportion of it in the horse; so that if we estimate the weight of a horse to be thirteen hundred and forty-four pounds, the whole quant.i.ty of blood will amount to eighty-four quarts, or one hundred and sixty-eight pounds; of which about forty-five quarts, or ninety pounds, will commonly flow from the jugular vein prior to death; though the loss of a much less quant.i.ty will deprive the animal of life."

REMARKS ON BLOOD-LETTING.

The author has been, for several years, engaged in a warfare against the use of the lancet in the treatment of the various diseases of animals.