CHAP. XII.] FATS AND CHOLESTERIX IN THE FAECES. 



459 



organic combination in the faeces as taurin, found that the total 

 quantity excreted in 24 hours only amounted to 0'32 grins. This 

 fact affords an additional proof that the bile acids are mainly re- 

 absorbed in the alimentary canal. 



Fats and i. Fats. Even the normal faeces of men on a 



mixed die ^ con tain small quantities of the neutral fats, 

 the quantity of palmitin and stearin being said to be 

 greater than that of the olein. When large quantities of fats, 

 especially of oils, are added to the diet, the faeces always contain an 

 excess of fat. Berths' 1 , in experiments upon himself, found that 

 when consuming daily a diet composed of 350 grms. of meat, 500 

 of bread, 60 of fat and 100 of fruit, the quantity of fat daily excreted 

 in the faeces amounted to 7 8 grms. On adding 60 grms. of cod- 

 liver oil to this diet, he excreted, on the 1st day 8 grms., on the 7th 

 day 12 grms., on the 12th day 18 grms., on the 20th day 22 grms., and 

 on the 30th day 49 grms. From this experiment it would appeal- 

 that, at first, the alimentary canal was able to absorb nearly the whole 

 of the extra fat, but that the capacity of absorption became gradually 

 impaired. 



The faeces always contain magnesium and calcium salts of the 

 fatty acids, which are often found crystallised. If the faeces be 

 thoroughly extracted with alcohol and with ether, so as to remove 

 the normal fats and the free fatty acids, and the insoluble residue 

 be then treated with hot acidulated alcohol, the fatty acids, previously 

 in combination with the alkaline earths, pass into solution. 



Lecithin is either absent, or present in traces, in the faeces. 



2. Cholesterin. The normal faeces always contain some chole- 

 sterin. According to Austin Flint, jun. 2 , the faeces do not contain 

 cholesterin, but a body derived from it to which he gave the name of 

 stercorin. It is the universal opinion that Flint's stercorin was merely 

 impure cholesterin. 



In 1857 Marcet 3 separated from the faeces of man a 

 body crystallising in shining needles, soluble in alcohol 

 and ether, insoluble in water, to which he gave the 

 name of excretin, and assigned the formula C 78 H 156 S0 2 . Hinterberger 4 

 afterwards made an elaborate investigation of this body and, by re- 

 crystallising it many times, obtained it free from sulphur. From 100 

 pounds of excrements he obtained 8 grms. of excretin. According to 

 this investigator, excretin has the empirical formula C 20 H 36 0. Unlike 



Excretin 

 and excre- 

 tolic acid. 



1 Berthe, quoted by Maly. Hermann's Handbuch, Vol. v. i. p. 243. 



2 Austin Flint, Jun., Eecherches experimentales sur une nouvelle fonction dufoie &c. 

 Paris, 1868. 



3 W. Marcet, ' On the immediate principles of human excrements in the healthy 

 state,' Philosophical Transactions, Vol. CXLVII. Part 1 (1857), pp. 403 413. Also 

 Annales de chimie et de phys., Vol. LIX. (1860), p. 91. 



4 F. Hinterberger, 'Ueber das Excretin,' Ann. d. Chem. u. Pharm., Vol. CLXVI. 

 (1873), p. 213. 



