FATTENING CATTLE. 



503 



the phenomena that liave been and are passed 

 away — the fin;? horses I have named were 

 almost exchisively fed upon oats and beans, 

 which are two of the most nutritious kinds of 

 all species of vegetable food ; wliiie, on tlie 

 other hand, tlioso horses jierforminj^ but a 

 small amount of laborious work, will supply 

 the natural waste of their bodies from the 

 very small (•oniiiarative (|uaiitity of f];liiten 

 which is found to bo contained in hay or clo- 

 ver, or both. 



I have alreaily informed you that the food 

 of classes of animals consists of two kinds of 

 distinct species of matter ; viz. the one which 

 possesses a great pro[)orti()n of azote, or nitro- 

 gen, as one of its principal constituents, and 

 whicli the Table I have referred to tells ns is 

 identical with the blood and muscular flesli 

 of the animal : the other ])ortion is destitute 

 of nitrogen, but consists of gum, starch, sugar 

 and woody fibre. Now, every one of these 

 different materials answers two quite distinct 

 but very important purjioscs in the economy 

 of every animal body. The first, or the nitro- 

 genous constituents, snpi)ly the waste which 

 has occurred in the fluids and tissues of the 

 body, and, as Dr. Magendie very properly 

 states, may justly be termed the elements of 

 nutrition ; the last, which are the non-nitro- 

 genous portion, act, if I may apply the ex- 

 pression, as fuel for combustion in the lungs, 

 in order to keep up the due supj)ly of animal 

 heat, and under some peculiar circumstances 

 also will contribute to the formation of fat. — 

 These elements may likewise be arranged 

 under two great heads, viz. those which are 

 necessary to the function of nutrition, and 

 those affecting that of respiration. 



I respectfully call your attention to the fol- 

 lowing Table, wherein they are exemplified : 



TABLE II. 

 1. Elements of Nutrition. 2. Elements of Respiration. 



Glnten. Gum. 



Albumen. Starch. 



Casein. Sugar. 



Flesh, or Mnscular Fibre. Oil or Fat. 



Blood. Alcohol. 



The elements of nutrition (No. 1) must of 

 necessity exist in combination with every sub- 

 stance which experience has taught us to be 

 capable of supplying food to the animal; but, 

 ere it can impart the nutritious properties, 

 numerous im])ortant mechanical and chi'mical 

 changes must undergo, ere it can take place. 

 The grand process of digestion must be per- 

 formed — by which I mean, the manner by 

 which the nutritient particles may be ren- 

 dered soluble, and not only capable of enter- 

 ing, but even of fonr^ig new blood. A brief 

 detail of the manner hi which this is performed 

 may not be uninteresting to some of my pre.s- 

 ent auditor}'. It is accomjilished in the fol- 

 lowing mamier: The food, when received 

 into the mouth, is broken down by the teeth, 

 where it becomes mixed with the saliva, 

 which is secreted by the glands that are situ- 

 ated near the angle of the jaw, and beneafe 

 (1023) 



the tongue ; when the process of mastication 

 is completed, the morsel is collected into a 

 ball at the base of the tongue, and by the act 

 of deglutition or swallowing it is carried past 

 the phai-ynx into the oesophagus or gullet, 

 down which it passes into the stomach, where 

 it enters at the cardiac orifice ; it remains 

 there for a short time, according to the nature 

 both of the animal and the food it has j)artHkeu 

 of, (in man it is su|)posed to be about two 

 hours.) Tlio chemical and mechanical action 

 that now takes place is technically called, in 

 I'hysiological language, the process of chymi 

 Jicnlion ; when this is ])erfected, the orifice 

 at the ojiposite extremity (denominated the 

 pylorus) becomes dilated, and the chyme 

 passes into the first of the small intestines, an 

 atoinically named i\\e. duodenum, where it be 

 comes mixed with the bile from the liver, and 

 the fluid from the panrrcos or sweat-bread 

 This being accomplishetl, the process ol' ckyl 

 ification now commences — a series of small, 

 minute vessels, named lactcals, whose mouths 

 open on the mucous (or villous) coat of the 

 bowel or intestine, which absorbs the nutri 

 tious portion of the food, (which resembles 

 milk in appearance, hence it is named chyle.) 

 This fluid, being conducted by numerou.s 

 branches, passes into one great reservoir, 

 called the thoracic duct, which ends 'in a 

 large vein near the heart (the left subclavian), 

 and there it is mixed witli the blood ; but be- 

 ing loaded with carbon, which is inimical to 

 the due preservation of animal life, the blood 

 passes from the heart to the lungs, where it 

 becomes oxygenized, and fit for all the pur- 

 poses of the animal economy. The non-nutri- 

 tious portion, from which the chyle has been 

 extracted, passes through the last of the small 

 intestines (the jejunum) into the whole course 

 of the larger part of the alimentaiy canal — 

 viz. the ccBcum, colon and rectum, and from 

 the last they are finally ejected fi'om the body 

 — ultimately again to reenter it in another 

 form, in consequence of its fonning manure, 

 and therefore afi'ordlng food for plants m the 

 maimer detailed in my former Lectures. 



But independent of the simple fact that the 

 salivary fluid, when commixed with the food, 

 renders the digestion of the aliment far more 

 easy, yet Baron Liebig imagines that it pos- 

 sesses the peculiar oflices of inclosing and 

 conibiiiing air, in the fonn of froth ; the oxy- 

 gen which it contains enters into union with 

 the constituents of the food, while the nitrogen 

 is again evolved through the medium of the 

 lungs and skin; this philosopher is likewise 

 of opinion that, in many of the herbivorous 

 quadrupeds, their taimination (as the oxen and 

 shf'ep, iiir example) lias for one of its princi- 

 [)al objects a com])lete renewal with the re- 

 pe ited introduction of pure oxygen into the 

 animal's stomach; and that, unless this takes 

 place, the fimction of nunination cannot be 

 did/ perfected in the stomach. I have given 

 you a brief outline of the manner in which 

 digestion is accomplished, but in doing so I 

 omitted to observe that attached to the mu- 



