ITS CONSTITUENTS. 65 



mus } Esox lucius. Perca fluviatilis) , Strecker found that the resin- 

 ous constituents consisted almost entirely of alkaline taurocholates, 

 with mere traces of alkaline glycocholates ; and, singularly enough, 

 that the potash-salts preponderated in the salt-water, and the 

 soda-salts in the fresh -water fishes. The researches of Strecker 

 show that the bile of the dog contains almost exclusively tauro- 

 cholate of soda, and a similar fact had been previously ascertained 

 by Schlieper in reference to serpents 5 bile. It seems, moreover, to 

 follow from Strecker's experiments, that the nature of the food 

 (in the case of dogs) exercises no influence on the composition of 

 the bile. The bile of the sheep contains, according to Strecker, a 

 mixture of much taurocholate of soda with a comparatively small 

 amount of glycocholate. The bile of the goose, according to 

 Marsson's investigations, contains almost exclusively taurocholic 

 acid. Hyocholic acid has only been found in the bile of the 

 pig; on the other hand, it appears that the small quantity of 

 sulphur formerly detected by Strecker and Bensch in the bile 

 of the pig depends on the presence of a hyocholeic acid; that is 

 to say, that besides the glycine-yielding hyocholic acid (glyco- 

 hyocholic acid), there also occurs a taurine-yielding acid in very 

 small quantity an acid in which the taurine is united with the 

 same resinous acid (C 50 H 40 O 8 , the hyocholalic acid of Strecker) 

 with which glycine is combined in hyocholic acid. The products 

 of the decomposition of hyocholic acid have been carefully 

 studied by Strecker. It is worthy of notice that this chemist, 

 in examining pigs 5 bile from which the biliary acids had been 

 removed by hydrochloric acid, discovered a very strong sulphurous 

 base, which is capable of combining even with carbonic acid. 



The peculiar pigment has never yet been found to be absent in 

 the bile of any animal. In the bile of carnivorous and omnivorous 

 animals, including man, we have a brown pigment, the chole- 

 pyrrhin of Berzelius; while in the bile of birds, fishes, and 

 amphibia, we usually find an intense green pigment, biliverdin. 

 The brown bile-pigment is moreover never contained in a state of 

 freedom, but is always in combination either with soda or lime ; 

 in the latter case it is insoluble, and may be easily recognized in 

 the brown granules which we sometimes observe in examining 

 the bile with the microscope. A microscopico-chemical analysis 

 affords a ready proof that these granules consist of the combina- 

 tion of cholepyrrhin with lime. 



The quantitative relations of the biliary constituents have not 

 as yet been very accurately investigated ; the following statements 



VOL. II. F 



