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



upon the addition of 18,190 parts of water ; from which it might 

 be inferred that a great mass of this fluid, at the boiling temper-! 

 ature, may dispose the super-margarate to be reduced to the 

 neutral margarate and the margaric acid. 



Boiling alcohol of the density of - 832 dissolves the super- 

 margarates in all proportions, when they do not contain any 

 margarate of lime. The following experiment may be cited as 

 an illustration of this property : 20 parts of alcohol dissolve 50 

 of the super-margarate of the ox at the temperature of 140° ; 

 the alcohol was then so far concentrated that the fluid was to 

 the super-margarate as one to six, yet no precipitate was formed. 



If we compare the acids of the different super-margarates 

 together, we shall find that they are all of a brilliant white 

 colour, insipid, nearly without odour, insoluble in water, and 

 soluble in all proportions in boiling alcohol. Their saturated 

 combination with potash is soluble in boiling water, and by cool- 

 ing is reduced to potash and an insoluble super-margarate. The 

 differences which they exhibit consist in their fusibility, and in 

 the disposition and size of the needles which are formed when 

 the margaric acid is suffered to cool on the surface of water. 

 The following is a more particular account of each of the indivi- 

 dual acids. 



The margaric acid of man was obtained under three different 

 forms ; I . In veiy fine long needles, disposed in flat stars ; 

 2. In very fine and very short needles, forming waved figures, 

 like those of the margaric acid of carcasses ; 3. In very large 

 brilliant crystals, disposed in stars perfectly similar to the mar- 

 garic acid of the hog. The thermometer plunged into these 

 last crystals in a state of fusion, sunk to 133-5°, and rose again 

 to 134° ; the first crystals melted at about 132°. 



The margaric acid of the sheep, when procured from the first 

 deposit of super-margarate which was formed in the soap, was 

 in the form of fine radiated needles ; the thermometer plunged 

 into it when fused, sunk to 139°, and rose again to 140°. The 

 acid which was procured from the last deposits of super-marga- 

 rate, crystallized in larger needles than the preceding, and melted 

 at 132 - 5°. The margaric acid of the ox crystallized in small 

 radiated needles ; when it became solid, the thermometer rose 

 from 139° to 140°. The margaric acid of the jaguar crystallized 

 in small radiated needles ; it was fusible at 131 - 5°. The margaric 

 acid of the goose crystallized in beautiful brilliant, narrow laminae, 

 like the margaric acid of the hog ; it melted at 131°. From this 

 statement we perceive that the margaric acids of the ox and the 

 sheep resemble each other the most nearly, as well in their form 

 as in the degree of their fusibility, that we may obtain the acids 

 of the human subject and the hog so as to exhibit similar proper- 

 ties, and that the acids of the jaguar and the goose very nearly 

 resemble them. The greatest difference in the degree of fusi- 

 bility is 9°. 



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