and the Cause of Epidemic Disorders. 115 



monly found in man and the domestic animals were ac- 

 curately distinguished, a fatty matter was regarded as hold- 

 ing a place among the constituent principles of blood, bile, 

 8ec. ; and it was stated that alcohol and ether, by reacting 

 upon fibrin, tendons, and the tissue which, by boiling water, 

 is transformed into gelatine, produced a fatty matter at the 

 expense of the elements of these substances. But here this 

 phrase, fatty matter, expressed nothing more than this, 

 namely, that there rvas found in the blood and in the bile, Sfc, 

 and so in the alcohol and ether which had acted upon these 

 animal substances, an inflammable matter which was insoluble 

 in water, and soluble in alcohol and in ether. Besides, the 

 most able chemist who would have endeavoured precisely to 

 have characterized these several fatty substances, without at 

 the same time undertaking a course of experiments upon all 

 the other substances besides those which were actually sub- 

 mitted to his analysis, would have thrown away his time, on 

 account of the substances detected in the blood, bile, &c. 

 being found in too insignificant proportions, and mixed 

 up with so many foreign bodies, that it would have been im- 

 possible for him to arrive at any precise result. This end, how- 

 ever, has been attained without difficulty when, in studying 

 the principal fatty substances, readily procm'able in quanti- 

 ties sufficient for all imaginable experiments, we commence 

 with the products of saponification, much more easily cha- 

 racterized than previous to that process. These last 

 have been successfully defined and characterized ; and fatty 

 bodies have been reduced, 1st, into perfectly defined acids ; 

 2dly, into neutral saponifiable bodies, that is to say, such as 

 are reduced by alkalies into different well defined products ; 

 and 3dly, into neutral unsaponifiable bodies. It has thus 

 been possible, and without much difficulty, to reduce the fatty 

 matter of the blood into the fatty matter of the brain, and 

 into margaritic and oleic acids, and cholesterine ; and the 

 fatty matter of the bile into cholesterine, and into margari- 

 tic, oleic, and other acids. It has also been easy to recog- 

 nise the fatty matter of the brain in the fibrin of the blood, 

 and stearine and oleine in those tissues which may be reduced 

 to gelatine. 



