THE PROTEIN-BODIES. 299 



of the animal, without any premonitory symptoms ; and very 

 similar, both in a toxicological and in a chemical point of view, is 

 the poison of the viper, as well as those poisons which are pro- 

 duced during contagious diseases, as hydrophobia, glanders, 

 typhus, &c. ; this view is, at all events, supported by the recent 

 experiments of Renault,* who convinced himself that both car- 

 nivorous and omnivorous animals could, without any detriment, 

 feed upon the flesh of animals which had been affected with these 

 diseases, while the juices of such flesh or similar effluvia, when 

 introduced directly into the blood or into a wound, occasion the 

 most fatal effects. 



This peculiar behaviour of all these substances proves that 

 they cannot be resorbed in an unchanged condition either by the 

 capillaries or the lymphatics of the intestinal canal. Since most 

 of them cannot be again recognised in the solid excrements, they 

 must undergo so complete a change through the action of the 

 digestive fluids, that when they at length make their way into the 

 blood, they can no longer exert their former poisonous actions. 

 Even if we cannot altogether agree with Bernardf in his view that 

 animal membranes are absolutely impenetrable to these substances 

 (emulsin, diastase, curarine, and the poison of the viper) this much, 

 at all events, is certain, that these substances, like albumen, exhibit 

 very slight endosmotic force. Mialhe and PressatJ have, more- 

 over, recently attempted to show that the fresh albumen of the 

 egg can only penetrate animal membranes when the latter have 

 attained a certain degree of putrefaction; but repeated experi- 

 ments with various animal membranes (previously treated with 

 alcohol, and afterwards rinsed with water) have convinced me that 

 they are not perfectly impenetrable by albumen, emulsin, and 

 diastase. The only point which is established beyond all doubt 

 is, that all these substances pass with difficulty through animal 

 membranes, and that their diffusibility is extremely small. 

 (Graham found the diffusibility of sugar 8 times as great, and 

 that of chloride of sodium 19 times as great, as that of albumen). 

 In the preceding remarks we can see the reason why the protein- 

 compounds, which are apparently ready to be applied at once to 

 the purposes of nutrition, must first undergo a metamorphosis 

 through the influence of the digestive juices before they are re- 

 sorbed. If it were not for the gastric and intestinal juices, soluble 



* Compt. rend. T. 33, pp. 532-535. 



t L'Union m&l. T. 3, pp. 445, 457, et 4(J1. 



% Compt. vend. T. 33, pp. 450-454. 



