ABSORPTION. 267 



traverse the entire intestinal tract without being resorbed. We 

 shall subsequently become better acquainted with those sub- 

 stances which are exclusively or principally absorbed by the 

 lacteals, whilst in the present place we will simply refer to such 

 extremely soluble matters as gum, turmeric, &c., which are not 

 absorbed from the intestinal canal either by the blood-vessels or 

 the lymphatics. To the last-named substances belong both the 

 curare-veneno (which is probably identical with the woorara) and 

 the poison of serpents. If from this we were to conclude, as has 

 actually been done, that nature in her wisdom has closed the 

 passage of this poison to the blood by both channels, the fact 

 would scarcely impress us very powerfully, when we remembered 

 that all access to the capillaries or the chyle was alike forbidden to 

 the comparatively harmless gum or turmeric as well as to serpents' 

 poison, which could only rarely find its way into the stomach, 

 whilst it opposes no hindrance to the absorption of other poisons 

 which rarely enter wounds but are of common occurrence in the 

 intestine. These considerations, together with the experiments of 

 Boussingault and Bernard (which certainly still require confirma- 

 tion), according to which an animal membrane that readily 

 permits the endosmotic passage of saline solutions is completely 

 impervious to curarine, emulsin, and diastase, sufficiently show 

 that the law of a physical necessity is here involved. Considering 

 the striking diversity of the above-named materials, we may still 

 hope,, notwithstanding our slight knowledge of the laws of diffu- 

 sion and of endosmosis through membranes, to discover certain 

 properties common to all these matters, on which we may suppose 

 this great capacity for absorption to depend. It is generally ad- 

 mitted that it is only soluble substances which admit of 

 resorption ; but the degree of solubility in these substances is so 

 different, that if there were not a number of very soluble bodies 

 which were not capable of resorption, we yet could not ascribe to 

 their solubility alone the capacity which they exhibit of being 

 absorbed by the capillaries. Unfortunately the greater number of 

 these substances have as yet been so imperfectly investigated in 

 reference to their capacity for diffusion and to the endosmotic 

 equivalent which is undoubtedly connected with it, that we are 

 still unable to demonstrate the dependence of their capacity for 

 absorption upon these properties ; but the analogy between sub- 

 stances found by Graham to be very diffusible and many of the 

 bodies already referred to, lends the greater probability to our 

 conjecture ; for we find that those substances which are very little 



