Increasing Quantities of Fat in Diet on Metabolism in Dogs. 293 



of the neutral fat and the fat acids as soaps. In some the quantity of fat 

 acids combined as soaps is much greater than the neutral fat, and in 

 others they are very much alike ; but at any rate the large intestine 

 -appears to have no influence whatever in altering the composition of 

 the fats in the faeces. On the other hand there is a difference in the 

 quantity of cholesterin present. 



It is seen that in the second normal dog the quantity of cholesterin 

 differs considerably from that seen in the first, and that results seen in 

 the partial removal of the large intestine correspond with the normal 

 dogs. On the other hand, in the two dogs in which the large intestine 

 was completely removed, the cholesterin found was small in quantity ; 

 .and if the averages are taken it is seen that the removal of the large 

 intestine tends to cause a decrease in the quantity of cholesterin daily 

 eliminated in the faeces. 



It has already been shown by Jankau* that large quantities of 

 cholesterin given by the mouth are absorbed, and therefore it is not at 

 all surprising if the quantities of cholesterin which are daily elimi- 

 nated in the bile, &c., are to a certain extent absorbed in the small 

 intestine, that the absence of the large intestine should have no effect 

 in increasing the quantity found in the faeces. At the same time, the 

 fact that the actual quantity of cholesterin found in the faeces appears 

 to be smaller in dogs without a large intestine, would appear to be ex- 

 plainable by the fact that the secretion of the large intestine itself 

 -contains cholesterin. Further, it is conceivable that it is not so readily 

 absorbed by the large intestine, hence the quantity of cholesterin 

 .normally present is larger than that found when the large intestine is 

 .absent. 



Before leaving the subject of the faeces, it is of interest to note their 

 alteration as regards colouring matter after the removal of the large 

 intestine. 



TJie Action of tlie Removal of the Large Intestine on the Urobilin Formation 



in the Faeces. 



In a paper already published I showed! how it seemed probable that 

 the presence of urobilin in the urine was due to the conversion of the 

 bile pigments during their passage along the intestines. 



Schmidt:}: showed that when a concentrated solution of perchloride 

 of mercury is applied to wet or dry faeces containing urobilin, in the 

 space of a few minutes a bright rose-red colour is developed. The 

 rose-coloured extract, when separated and examined with the spectro- 

 scope, shows the urobilin band between F and b. This test is all the 



* Jankau, ' Archiv f. Exp. Path. u. Pharm.,' vol. 29, p. 237, 1892. 



f Yaughan Harley, 'Brit. Med. Journ.,' Oct. 3rd, 1896. 



2 Schmidt, ' Verhandlungen d. Congress f . Universale Medicin,' p. 320, 1895. 



