46 HANDBOOK FOR BIO-CHEMICAL LABORATORY. 



Properties. Sarcolactic acid occurs as a syrup, which dis- 

 solves in water, alcohol, and ether readily. It is dextro-rota- 

 tory, but its salts, on the other hand, are laevo-rotatory. Its 

 zinc salt crystallizes with 2 mol. (12.9$) water of crystalliza- 

 tion as small four-sided prisms, which dissolve in 17.5 parts 

 water, its calcium salt containing 24.83-26. 21$ (4 or 4.5 mol.) 

 water of crystallization, and dissolving in 12.4 parts water. 



Protagon. 



Preparation. An ox-brain as fresh as possible, with the 

 blood and membranes carefully removed, is ground fine and 

 then extracted for several hours with 85$ alcohol at 45 C., 

 filtered while hot, and the residue extracted with warm alco- 

 hol until the filtrate fails to yield a precipitate at C. The 

 several alcoholic extracts are cooled to C., and the precipi- 

 tates united and completely extracted with cold ether, which 

 removes cholesterin and lecithin-like bodies. The residue is 

 strongly pressed between filter-paper and allowed to dry over 

 sulphuric acid or phosphoric anhydride. The resulting mass 

 is powdered, moistened with water digested for many hours 

 with alcohol at 45 C., filtered, slowly cooled to C. The 

 crystals may be purified by recrystallization. (Gamgee and 

 Blankenlwrn.) 



Properties. Protagon appears when dry as a white, loose 

 crystalline powder. It is soluble with difficulty in cold, but 

 more easily soluble in warm, alcohol and ether. At tempera- 

 tures above 55 C. its solutions decompose. It swells up in 

 little water, decomposes partly, and gives myaline forms. It 

 is soluble in glacial acetic acid, which deposits crystalline 

 forms on cooling. When boiled with a solution of Ba(OH) 2 , 

 protagon decomposes into glycero-phosphoric acid, fatty acids, 

 and neurine. It melts at 200 C., forming a brown syrup. 



