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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![fluidity should be unfavourable to the process of digestion, more especially as it seems essential to those of fermentation and chemi- cal solution. The requisite degree of solidity I should suppose to be that of curd, or what is produced by the coagulation ot animal mucilages, as of the white of an egg. But this is only supposition, founded on the idea that Nature's general principles are right, and all the corresponding parts adapted to one another, except when monstrous, either in form or action. Mastication is the effect of a mechanical power, produced by parts particularly provided for that purpose, which are of various kinds, fitted for that sort of food on which the animal is by Nature intended to live, and may be imitated with equal advantage by many other pieces of mechanism. The masticating powers are of three kinds. The first is that which merely fits the substance for deglutition, as in the lion and many other carnivorous animals ; and which, in the ruminating tribe, renders the food fit to be swallowed, that it may undergo such preparation in the first stomach as is necessary before it is further masticated for digestion. The second is that which not only fits the food for deglutition, but exposes it to the action of the gastric juice, by breaking the shells or husks in which the nourishment is contained, and in which it would be defended from the powers of digestion. And the third is that which divides and bruises the food before it is received into the stomach ; which mastication is of con- siderable service, by producing a saving in food.* The husk of the seeds of plants, although a vegetable substance, appears to be indigestible in its natural state. Whether this arises from the nature of the husk itself, or from its compactness, I am not quite certain, but am inclined to suppose the last, as we find the cocoa, which is only a husk, to be digestible when ground to a powder and well boiled. We know likewise that cuticle, horn, hair, and feathers, although animal substances, are not affected, in the first instance, by the gastric juice ; yet if reduced in Papin's digester to a jelly, that jelly can be acted upon in the stomach : we must therefore suppose that a certain natural degree of solidity in animal and vegetable substances renders them indigestible. This com- pactness in the husk seems to be intended to preserve, while under ground, the farinaceous part of the seed, in which the living principle is placed, the husk having probably no other power of resisting putrefaction than what arises from its texture ; but whatever may be the use of the husk, it must be connected with the vegetative process of the plant. The same purpose of preservation is pro- bably answered by the shells of all ova. Although husks are not capable of being dissolved in the gastric juice, they allow of transu- dation, and that the seed is in some degree affected by it is known quent process; for gelatin, a staminal alimentary principle, nearly resembling albumen in its composition, undergoes, under similar circumstances, no such solidifying change. (Br. Tr., p. 494.)] * [Blumenbach has well suggested that the vitality of the seeds is thus de- stroyed and they are made subject to the influence of the gastric juice.]](https://iiif.wellcomecollection.org/image/b21131545_0104.jp2/full/800%2C/0/default.jpg)
