vi INTESTINE AS AN OEGAN OF EXCEETION 353 



compact mass represented a concentration of the intestinal secre- 

 tion, which must accordingly play a prominent part in the 

 formation of the faeces. 



Hermann's observations were much extended and varied by 

 his pupils Ehrenthal and Blitstein (1891), and by Berenstein 

 (1893). Besides employing the intestinal ring, the two first- 

 named caused dogs with a fistula of the gall-bladder to fast, so as 

 to exclude any bile from the faeces formed in the intestine. They 

 further made observations on the faecal masses produced in the 

 last part of the intestine, after establishing a preternatural anus in 

 the ileum, and occluding the lower end of the bowel as a cul de sac. 

 The whole of the digestive juices except the succus entericus are 

 cut off from these faeces. 



The results were tolerably concordant. Both within the ring of 

 intestine, and in the faeces of the fasting dog with fistula of the 

 gall-bladder, and also in the last part of the bowel of dogs with a 

 preternatural anus, i.e. cut off from the digestive processes, they 

 found on section masses that were partly fluid, partly of a soft 

 consistency, composed principally of epithelial detritus with 

 innumerable hosts of bacteria. According to the above authors 

 these faecal masses must consist principally of the epithelium cells 

 which are continually shed from the mucous membrane, and which 

 mingle with the succus entericus, and are converted by bacterial 

 action into structureless detritus. 



It is a remarkable fact that no unmistakably epithelial 

 structures can be, recognised in the masses collected within the 

 intestinal ring, or in the blackish faeces formed during fasting. by 

 dogs with fistula of the gall-bladder. Ehrenthal ascribes this to 

 the fact that in the first case the bacteria (which increase 

 enormously within the closed ring), and in the second case the 

 pancreatic juice poured out into the intestine, digest the detached 

 epithelial cells, and convert them into formless detritus. In the 

 faecal masses formed in the last part of the bowel in dogs with a 

 preternatural anus, the microscope, on the contrary, shows not a 

 few well-preserved epithelial cells, perhaps because they can be 

 expelled by the natural anus before undergoing complete bacterial 

 disintegration. 



Ehrenthal and Blitstein concluded from these researches as 

 a whole (conformably with the opinion already expressed by 

 Heidenhain), that the chief mass of the faeces formed under the 

 above experimental conditions is derived less from concentrated 

 secretions of the intestine than from the detached and disintegrated 

 epithelia of the mucous membrane. 



Berenstein's subsequent work tended to correct this opinion. 

 He modified the method of research, experimenting with short 

 isolated segments of intestine, and also with the isolated Thiry- 

 Vella loop, and disinfected the isolated segments of the gut -more 



VOL. II 2 A 



