ABSORPTION OF POISONS. 625 



quickly the colloidal albuminoids of the food, which they help to dis- 

 solve, yet acidity appears to be opposed to the absorption not only of 

 fat. but of actually dissolved substances ; whilst a neutral or alkaline 

 condition favors their absorption. In certain cases, especially in re- 

 gard to organic substances of an extraneous, medicinal, or poisonous 

 character, it appears that the digestive fluids not only dissolve, but 

 also alter, the properties of substances taken into the stomach. Thus, 

 there are two substances found together in the bitter almond, named 

 amygdalin and emulsin, the former of which is decomposed by a cata- 

 lytic action of the latter, and gives rise to the formation of prussic 

 acid. Now, it has been found by Bernard, that amygdalin, introduced 

 by itself into the stomach of any animal, is digested, dissolved, and 

 absorbed, without giving rise to poisonous symptoms. Again, emul- 

 sin alone taken into the stomach produces no ill effects. If, however, 

 after the absorption of the dissolved amygdalin from the stomach, 

 emulsin be directly injected into a vein, death speedily ensues, from 

 the formation of prussic acid in the blood or tissues, by the decompo- 

 sition of the dissolved amygdalin under the influence of the emulsin, 

 thus introduced into the circulation, and brought into relation with it. 

 But on the other hand, if the emulsin be introduced into the stomach, 

 and the amygdalin be injected into the bloodvessels, poisoning does 

 not ensue, showing either that the emulsin is not absorbed from the 

 alimentary canal, or that its properties are destroyed. The latter is, 

 probably, the case, for emulsin is easily soluble, and when it and the 

 amygdalin are introduced together into a vein, or even into distant 

 parts of the circulation, their meeting in the blood is immediately fol- 

 lowed by the characteristic decomposition of the one under the influ- 

 ence of the other, prussic acid being evolved, and the animal being- 

 killed. 



After the absorbed materials have entered through the capillary 

 walls, their onward progress depends upon the forces concerned in the 

 circulation of the blood. 



The process of absorption by the lacteals is of a more special nature 

 than that by the bloodvessels; for though they admit the entrance, 

 probably by simple dialysis, of water, with traces of saline, saccharine, 

 and extractive substances, that is, of the crystalloid bodies, and also 

 take up in certain proportion, the dialyzable albuminose, yet they are 

 specially characterized by absorbing fatty matters, which, though crys- 

 talloid, are insoluble in water, and non-dialyzable, unless they are 

 actually saponified. In the alimentary canal, however, they are merely 

 liquefied, or emulsified, i. e., reduced to a state of extreme molecular 

 subdivision, or they are decomposed into their fatty acids and glycerin. 

 The special power of the lacteals, of absorbing fatty matters, has not 

 yet been fully explained. Some have supposed that the fats pass 

 through the epithelial substance of the villi, into the lacteals, in a state 

 of saponification and solution, and then reappear as neutral fats in the 

 chyle. The action of the bile and of the alkaline pancreatic and intes- 

 tinal juices, as already explained, undoubtedly prepares the fatty mat- 

 ters for more easy penetration into the lacteals. The epithelial cells 

 of the villi, which are often found distended with drops of fat during 



40 



