186 OF ABSORPTION AND SANGUIFICATION. 



and capacious alimentary tracts. Bischoff, Meyer, and Voit 1 have shown 

 that a bread diet given to dogs causes a great increase in the amount of 

 faeces ; and Brucke 2 points out that the remarkably different effects observed 

 by different persons who have submitted themselves to the so-called Banting's 

 cure some of whom complain of constipation, while others suffer from diar- 

 rhoea is referable to the fact that whilst an exclusive meat diet is apt to 

 cause diarrhoea, it always causes great diminution in the amount of fbeces 

 excreted ; readily giving rise to the idea that constipation is present. 3. The 

 tilbuminous compounds are in part absorbed directly into the blood, but for 

 the most part undergo conversion into peptone in the stomach by the gastric 

 juice, and this change is continued in the small intestines by the action of 

 the pancreatic fluid and succus entericus; so that in the case of muscle but 

 few and small remains enter the large intestine. The gelatin-yielding tis- 

 sues, especially when they have been previously cooked, appear to be readily 

 dissolved and absorbed ; as are also such substances as brain, and the tissue 

 of glands generally (liver, pancreas, thymus, and kidney). Such portions 

 as escape the action of the above-mentioned fluids, and reach the large intes- 

 tine, are subject to a kind of secondary digestion, effected, as Blondlot sup- 

 poses, by the lactic and other acids that are there developed ; so that but 

 small quantities are discharged with the feeces. Lastly, mineral compounds, 

 and the various fermented beverages, are but little altered in their passage 

 through the alimentary canal, being directly taken up by the bloodvessels 

 and lymphatics. 



CHAPTER VI. 



OF ABSORPTION AND SANGUIFICATION. 



1. Of Absorption from the Digestive Cavity. 



133. So long as the Alimentary matter remains in the Digestive cavity, 

 however perfect may be its state of preparation, it is as far from being con- 

 ducive to the nutrition of the system, as if it were in contact with the ex- 

 ternal surface. It is only when absorbed into the vessels, and carried by 

 the circulating current through the very substance of the body, that it be- 

 comes capable of being appropriated by its various tissues and organs. la 

 Man, as in nearly all Vertebrated animals, a set of vessels is interposed be- 

 tween the walls of the intestine and the sauguiferous system, for the pur- 

 pose, as it would seem, of taking up certain components of the nutritive 

 mutter, of which part at least are not in a state of perfect solution, and of 

 preparing them for being introduced into the current of the blood. These are 

 the Absorbents of the intestinal walls; of which those that are found, after 

 the performance of the digestive process, to contain the white opalescent 

 fluid known as "chyle," are distinguished as lacteals; while the remainder, 

 like the absorbents of the system generally, are known as lymphatics. The dis- 

 tinction is a purely artificial one for the "lacteals" and the "lymphatics" 

 of those parts of the intestinal walls which they supply, as is shown by the 

 fact that, during the intervals of the digestive process, they contain a trans- 

 parent fluid in all respects similar to the "lymph" of other parts. The ab- 



1 Zeitsclirift fiir Biologic, Band v, vi, vii, viii, 1869-73. 

 8 Vorlesu ngen, 1874, p. 336. 



