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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![neither be much complicated, nor have any immediate relation to those branches of knowledge with which they have had few oppor- tunities of being acquainted: at best, they will seldom go further than to explain a single fact. To look through a microscope and examine the red globules of blood, to view animalculae, and give a candid account of what they see, are points on which such inquirers may be allowed to indulge themselves ; but it is presumption in them to affect to reason of a science in which they can have but a very superficial knowledge, or to expect to throw light on subjects that they have not taken the previous steps to understand. It should be remembered that nothing in Nature stands alone; but that every art and science has a relation to some other art or science, and that it requires a knowledge of those others, as far as this connexion takes place, to enable us to become perfect in that which engages our particular attention. These strictures are applicable to all those who have made experiments to explain digestion. The effect of the mechanical powers being easily understood, those who considered digestion mechanically have in general explained them justly as far as they applied to the gizzard ; but their reasoning went no further, and they supposed these effects to be digestion. Those again who took it up chemically, being little acquainted with chemistry and totally ignorant of the principles of the animal oeconomy, have erroneously explained the operations of the animal machine as subject to the laws of chemistry. The first inquirers into digestion, struck only by the extremes of structure, the gizzard, and membranous stomach, paid no regard to the gradations leading from the one to the other ; which, if properly examined, would have materially assisted them to explain the functions of the stomach. Vallisneri, considering the power of the gizzard in one view only, imagined it would be as liable to be affected by the mechanical powers necessary for digestion as the grain which was to be digest- ed ; therefore supposed the existence of a solvent. But though Vallisneri is entitled to no merit from this idea, as the premises are false, yet this opinion of his set Reaumur to work, and has been the means of bringing several curious facts to light.* The experiments of Reaumur were first made with a view to confute that opinion, * [In this historical sketch, so rare in the writings of Hunter, of the opinions entertained by previous physiologists on the subject of digestion, the suggestion by Tyson of the existence and use of a solvent or corrodent fluid ouahtTo have had a place. In his Anatomy of a Rattlesnake he observes, The food, before it can prove aliment, must be comminuted, and broken into the smallest particles ; which in these membranous stomachs I can't see how it can be performed but by corrosion A principal menstruum in doing this I take to be that liquor which is discharged by the glands that are seated, in some, at the beginning of the threat, and are called sahvah or just above the stomach or gizzard of birds, and called the echmus ,■ or in others in the stomach itself, and called the glandulus coat, and such I take the inner coat of the stomach of our rattlesnake to be _ Fhilos. Trans., xiii. 1683, p. 33.]](https://iiif.wellcomecollection.org/image/b21131545_0080.jp2/full/800%2C/0/default.jpg)
