A text-book of physiological chemistry : for students of medicine and physicians / by Charles E. Simon.

  • Charles Edmund Simon
Date:
1904
Catalogue details

Licence: Public Domain Mark

Credit: A text-book of physiological chemistry : for students of medicine and physicians / by Charles E. Simon. Source: Wellcome Collection.

Provider: This material has been provided by the Augustus C. Long Health Sciences Library at Columbia University and Columbia University Libraries/Information Services, through the Medical Heritage Library. The original may be consulted at the the Augustus C. Long Health Sciences Library at Columbia University and Columbia University.

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    of which three are now recognized. These are known as cerebrin, kerasin, or horaocerebrin, and encephalin. Others also may possibly exist, and it is likely that the pyosin and pyogenin, which Kossel and Freitag obtained from pus, belong to this order. On boiling with dilate mineral acids protagon also yields a re- ducing substance, which is commonly regarded as galactose, and is referable to the decomposition of the glucosides just mentioned. Protagon is easily soluble in warm alcohol and ether, while in cold alcohol and cold ether it dissolves with difficulty. On cooling the substance crystallizes out in fine needles or in waxy masses, which can readily be broken up into a fine po\vder. On heating its alcoholic solutions to a temperature of 48° C. or on boiling its ethereal solutions the substance is readily decomposed into its com- ponents, as indicated above. In the dry state it can be heated to a higher temperature, but it is then also decomposed before 100° C. is reached. The resulting products melt between 200° and 203° C, and begin to volatilize at 220°. When moistened with water, the substance swells and is partly decomposed, with the formation of so-called myelin droplets. If much water is added, an opaque fluid is obtained. Isolation.—To isolate protagon from brain-tissue this should be as fresh as possible, as otherwise partial decomposition occurs spon- taneously. The material is freed from its membranes and adhering blood, and is then stirred to a ])ulp, and extracted with 85 per cent, alcohol, at a temperature of 45° 0., using fresh portions of alcohol from time to time until a specimen no longer deposits a sediment when cooled to 0° C. The extracts are filtered at 45° C, and sub- sequently kept at 0° C. The resulting precipitates are extracted with cold ether to remove cholesterins and lecithins, when the remaining material is pressed between filter paper and dried over sulphuric acid. It is finally pulverized, again extracted with alcohol at 45° C, when the solution is filtered and cooled to 0° C. To purify the substance it is recrystallized from warm alcohol or ether. Cerebrin.—Cerebrin, as I have stated, is a normal decomposition- product of protagon, but probably does not occur in the livnng nerve-tissue as such. Associated with lecithin, it is also found in the stroma of the red corpuscles of the blood, in leucocytes, in sper- matozoa, in the spleen, in the yolk of birds' eggs, etc. It is questionable, however, whether it actually exists in the froe% state, and the fact of its constant association with lecithin rather suggests that here also it is primarily present in the protagon molecule. Cerebrin is said to have the formula C^oHi^QNoOig. Elementary analysis has given the following results: C, 69.08 per cent. ; H, 11.47; N, 2.13; O, 17.32. On decomposition with boiling mineral acids it yields a reducing substance which is commonly regarded as galactose. On oxidation with nitric acid or on fusion with caustic alkali palmitic acid or stearic acid is obtained. If 26
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