NATURE OF CHYMIFICATION. 345 



water. "The solid and tenacious albumen is thus reduced to the weakest 

 possible state, to the state as it were of infancy ; in short, to a state precisely 

 analogous to that of the weak sugars and other organic compounds, as compared 

 with the strong and perfect varieties of the same substances." * 



460. In regard to the operation of the Digestive process upon the non-azotized 

 vegetable matters, which belong to the class of saccharine compounds, less cer- 

 tain information has been obtained. As already stated ( 430) it seems to be 

 the prevalent belief of Chemists of the present day, that they are incapable of 

 undergoing conversion into protein-compounds. By Dr. Prout, however, it is 

 distinctly asserted that, where no azotized matter* existed in the food, (the ani- 

 mal being fed, for example, upon pure starch,) and where no albumen was 

 found in the stomach, that principle was distinctly traceable in the contents of 

 the duodenum, after the admixture of the biliary and pancreatic fluids. Still 

 there is not sufficient evidence that such a conversion takes place; for the 

 albumen might have been derived from the blood circulating in the walls of 

 the cavity, the fluid portion of which would naturally undergo an interchange 

 with the thick gummy solution in the intestine, by a process of Endosmose. 

 By Dr. Proutt it is supposed that, "under ordinary circumstances, the azote 

 is principally furnished by a highly azotized substance (organized urea?) 

 secreted from the blood, either into the stomach or duodenum,;]: or into both these 

 localities ; and that the portion of the blood thus deprived of its azote is sepa- 

 rated from the general mass of blood by the liver, as one of the constituents 

 of the bile ; which secretion, as a whole, is remarkably deficient in azote." 

 As the Saccharine principles cannot be distinctly recognized either in the 

 blood or chyle (in a state of health), it is doubtful whether they can be absorbed 

 without undergoing conversion. Their simplest transformation is into lactic 

 acid; which may probably be absorbed directly from the stomach, by the 

 blood-vessels of its villi. But there is evidence that they may be also con- 

 verted into oleaginous compounds; and they probably form a considerable 

 part of the fatty matter contained in the chyle, the quantity of which seems 

 often greater than that pre-existing in the food. The possibility of such a 

 conversion (which has been denied by some eminent chemists), has recently 

 been demonstrated by the careful repetition of the old experiment of Huber ; 

 who showed that Bees, when fed upon honey alone, have the power of form- 

 ing wax to an amount much greater than that which the honey contained. 

 The oleaginous compounds forming part of the food are probably absorbed as 

 such ; and, in common with those produced by the transformation just de- 

 scribed, are either used for the maintenance of the respiratory process, or are 

 deposited as fat. The question whether they can ever, by any addition of 

 highly-azotized matter, be converted into protein-compounds, and thus be 

 applied to the nutrition of the azotized tissues, still, in the Author's opinion, 

 remains undecided; although there are not wanting those who speak quite 

 decidedly upon the impossibility of such transformation. 



VI. Lacteal and Lymphatic Absorption. 



461. Although there can be no doubt that the Mucous membrane is capable 

 of absorbing by its whole surface, it can scarcely be questioned that this func- 

 tion is most energetically performed by the villi which cover it. These are 

 short processes, from a quarter of a line to a line and a half in length ; giving 

 to the membrane, where they are most numerous, a fleecy appearance. In 



* Bridgewaler Treatise, p. 503* 



f On Stomach and Urinary Diseases, [Am. ed., p. 370, note.] 



* May this be the function of the glands of Brunner, which are situated in the duode- 

 dum and commencement of the jejunum only? w. u. c. 



