CRYSTALL1ZABLE NITROGENOUS MATTERS. 103 



variety of mucilaginous or oily looking drops and filaments, of double 

 contour, which exude from the edges of the mass, and remain separate 

 and insoluble ; resembling the microscopic forms produced under simi- 

 lar circumstances from the "myeline," or medullary layer of nerve 

 fibres. It is readily soluble in alcohol, less so in ether, and is also solu- 

 ble to some extent in chloroform and the fatty oils. It is readily 

 decomposed on standing, either in solution or in a state of watery 

 imbibition, acquiring an acid reaction. Decomposition is also effected 

 by the action of acids or alkalies. By boiling with baryta water it 

 suffers a characteristic alteration, giving rise to the production of two 

 new bodies; namely, a nitrogenous alkaline substance and phospho- 

 gly eerie acid. 



Lecithine has a special importance, not only as an abundant ingre- 

 dient of the nervous tissue, but also as being the only organic combina- 

 tion in the body containing phosphorus. Considering the number of 

 vegetable and animal articles of food in which it is an ingredient, it is 

 evident that a considerable quantity must be introduced with the nutri- 

 ment into the system and assimilated by the tissues, particularly by 

 those of the nerves and nervous centres. But as no known organic 

 combination of phosphorus is discharged with the excretions, this sub- 

 stance must pass out of the body as part of the phosphates which 

 appear in the urine and the perspiration. On this account, together 

 with the known fact of the constant consumption of oxygen by the 

 animal body, it is believed that the phosphorus, introduced as an ingre- 

 dient of organic materials, is converted by oxidation in the system 

 into phosphoric acid, and thus appears finally under the form of phos- 

 phatic salts. 



Cerebrine, C 17 H 33 N0 3 . 



As its name indicates, this is an ingredient of the brain and nerves, 

 the only healthy constituents of the body in which it is known to exist. 

 Although this substance has not been obtained in a crystalline form, 

 it is placed among the members of this group because it resembles 

 them in the general features of its chemical composition, particularly in 

 its small proportion of nitrogen, and also in certain of its reactions, 

 which are entirely dissimilar to those of an albuminous matter. 



Cerebrine is insoluble in water, but if moistened swells up slowly 

 into a pasty mass. It is insoluble in ether and in cold alcohol. 



It is readily soluble in boiling absolute alcohol, from which it is 

 again deposited on cooling. Boiling with baryta water decomposes it 

 very slowly and incompletely, and does not produce phosphoglyceric 

 acid, by which means it may be distinguished from lecithine. If 

 strongly heated in the air, it turns brown, melts, and finally burns with 

 a bright flame. 



It is much more abundant in the white than in the gray substance of 

 the brain, forming, according to Petrowsky, in the solid ingredients of 

 the white substance 9.5 per cent., in those of the gray substance but 



