THE VOLATILE PART OP PLAUTS, 93 



According to Hoppe-Seyler, {Med. Chem. Vhters., I,) the phospliorized 

 principle of oil of maize, and of the brain, nerves, yolk of eg'gs, etc., is 

 primarily tlie substance discovered in 186-1: by Liebreich, in the brain, 

 and termed I'rotagon. It is a white crystallized body, having the 

 following composition : 



Carbon, 67.3 



Hydrogen, 11.6 



Nitrogen, 2.7 



Phosphorus, 1.5 



Oxygen, 17.0 



100.0 

 Its formula is Cue, Han, N,, P, Ojj. When heated to the boiling point 

 it is decomposed, and yields among other products glycerin, phosphor- 

 ic acid, and stearic acid. {Ann. Ch. Fh., 134, p. 30). 



Saponification. — The fats are characterized by forming 

 soaps when heated with strong potash or soda-lye. They 

 are by this means decomposed, and give rise to fatty 

 acids, which remain combined with the alkalies, and to 

 glycerin, a kind of liquid sugar. 



Exp. 41. — Heat a bit of tallow with strong solution of caustic potash 

 until it completely disappears, and a soap, soluble in watjr, is obtained. 

 To one-half the hot solution of soap, add chlorhydric acid until the 

 latter predominates. An oil will separate which gathers at the top of 

 the liquid, and on cooling, solidifies to a cake. This is not, however, 

 the original fit. It has a different melting point, and a different chemi- 

 cal composition. It is composed^ of one or several fatty acids, corre- 

 sponding to the elementary fats from which it was produced. 



When saponified by the action of potash, stearin yields 

 stearic acid, C^, Hj, O^; palmitin yields palmitic acid, 

 Cjj Hj, Oj ; and olein gives oleic acid, C,, Hj^ O^. The 

 so-called stearin candles are a mixture of stearic and 

 palmitic acids. The glycerin, C^ H3 Oj, that is simulta- 

 neously produced, remains dissolved in the liquid. Glyce- 

 rin is now found in commerce in a nearly pure state, as a 

 colorless, syrupy liquid, having a pleasant sweet taste. 



The chemical act of Baponificatiou consists in the re-arrangement 

 of the elements of one molecule of fat and three molecul es of water in- 

 to three molecules of fatty acid, and one molecule of glycerin. 



JMmitln Water. Palmitic acid. Olycenn. 



On H,s 0, + 3 (Ha O) — 3 (C,a Hsj O^) -I- C3 H, 0^ 



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