274 M. Chevreul on Fatty Bodies, and [Oct. 



formed with a weak solution of potash a perfectly limpid solu- 

 tion, and was reduced into the pearly matter and an oleate of 

 potash. The alcohol, which was separated from the flakes, and 

 which had dissolved the greatest part of the matter subjected to 

 its action, was evaporated ; the residuum, still containing barytes, 

 was treated with cold alcohol, the solution, when separated by 

 filtration from some flakes of the soap of barytes which were not 

 dissolved, yielded a fatty matter which was free from barytes. 



This matter was fusible at 125-5° ; by cooling it crystallized in 

 small radiated needles ; it was white, but when fluid, of a light 

 lemon colour. By being heated in a platinum capsule on the 

 sand-bath, it melted, and the greatest part of it was evaporated; 

 by increasing the heat, it inflamed, and a little carbon was left, 

 which burned, leaving a residuum too minute to be appreciated 

 by the balance. Alcohol of the specific gravity of -812 dissolved 

 it in all proportions at the temperature of 129°. The solution 

 had no action on litmus or hematine ; when cooled, it deposited 

 crystals which were not as brilliant as those of cetine. Cetine is 

 also much less soluble in alcohol ; for five parts of alcohol of the 

 specific gravity of -791, which, when heated, dissolved 0-792 

 parts of cetine, deposited a great part of it at the end of 24 hours, 

 while the solution of this other substance did not become turbid. 



Two equal portions of the fatty substance were taken ; one 

 was put into pure water, the other into water slightly alkaline ; 

 they were digested during two hours, twice evaporated to dry- 

 ness, and the residue had each time water added to it. No 

 mucilage was obtained by this process, and none was obtained 

 when the alkaline part of the second portion was replaced by pure 

 water, and when, by being melted several times in water, it was 

 obtained free from potash. The fatty matter kept in pure water 

 became white on its surface ; but after being exposed for a 

 moment to the sun, it became yellow and semi-transparent ; in 

 this state it melted without disengaging any water. Hence if 

 follows that the fatty matter fusible at 125-5°, which is obtained 

 from cetine by treating it with potash, is not acid, when it has 

 been purified by barytes and alcohol from a small quantity of the 

 margaric and oleic acids, and that it is not susceptible of forming 

 a mucilage with potash. 



Having now observed the action of potash and of the saponified 

 part of the cetine upon the part which is not saponified, our next 

 object will be to examine the action of the water of potash, and 

 of the margaric acid upon cetine. Eleven parts of margaric acid 

 which was fusible at 129°, and seven parts of cetine fusible at 

 118-5° were employed, this being nearly the proportion in which 

 the saponified and the unsaponified cetine exist in the cetine 

 which has been subjected to the action of potash : 16 parts of 

 water and 18 of potash were added. The mixture was heated, 

 and a gelatinous magma was formed; to this a quantity of water 

 was added ;" it was boiled for some time, digested during two 



