Observations on certain parts of the animal oeconomy : inclusive of several papers from the Philosophical transactions, etc. / by John Hunter ... ; with notes by Richard Owen.
- John Hunter
- Date:
- 1840
Licence: Public Domain Mark
Credit: Observations on certain parts of the animal oeconomy : inclusive of several papers from the Philosophical transactions, etc. / by John Hunter ... ; with notes by Richard Owen. Source: Wellcome Collection.
Provider: This material has been provided by the National Library of Medicine (U.S.), through the Medical Heritage Library. The original may be consulted at the National Library of Medicine (U.S.)
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![ously putrid, is similar to the second of the three changes which takes place in digestion; and is only preparatory to the complete change, whether that be digestion or putrefaction. It appears from many experiments that the digested or animalized part, when carried into the intestine, is attracted by the villous coat, or clings to it as if entangled among the villi; while the excremen- titious part, such as bile, is found lying unconnected in the gut, as if separated from the other.* The food of animals in general consists of vegetable or animal substances; and vegetables seem intended to support one class, with a view to its being the food of another. Although there are classes of animals intended to subsist on each particular kind of food, yet they do not all invariably keep to the same kind in every stage of life, many being nourished by animal food when young that afterwards live on vegetables ; which circumstance will be more fully discussed while treating of the first food of pigeons. All stomachs do not equally digest the same substance, although it be their natural food. The caterpillar digests the expressed juice, but not the substance; while other animals are capable of dissolving nearly the whole. Some animals, as the common cattle, can feed on a variety of vegetables, although they may have a preference ; but there are others that will hardly eat of more than one kind. Of this last sort are insects in general, and the silkworm will scarcely touch anything but mulberry leaves; but I believe those that live upon animal food are not so restricted in their choice. It is probable that all animal and vegetable substances are equally capable of being digested, if equally soft in their texture; but some being much firmer in that respect, and others also united with in- digestible matter, as the earth in bones, more strongly resist the powers of the gastric juice; therefore mastication and trituration become necessary to bring them to a similar consistence. But sub- stances may be rendered too soft, for a fluid is difficult of digestion ; and we may observe, that Nature having given us very few fluids as articles of food, to render these few fitter for the action of the digestive powers, a coagulating principle is provided to give them some degree of solidity.f It is not easy to assign a reason why * [In chylification, the alkaline principles of the bile combine with the acids which the chyme has received in its formation in the stomach, and the albumi- nous or chylous principles are developed and attracted by the villi; while the resinous parts of the bile, combined with the excrementitious particles of the chyme, are more or less completely separated. The most characteristic change which, according to Prout, takes place in the intestine is the conversion of part of the chyme into albumen, which happens even when no albuminous matter was originally contained in the food or formed in the stomach.] f The circumstance of the crystalline humour, which is solid, being coagulated prior to its being digested, renders it probable that all animal substances go through that process, and that the loss of texture which they undergo arises from coagulation.a a [This coagulation happens to all animal substances which contain albumen; but can hardly be considered, Dr. Prout observes, to be essential to the subse- 13*](https://iiif.wellcomecollection.org/image/b21131545_0103.jp2/full/800%2C/0/default.jpg)
