44 PHYSIOLOGICAL CHEMISTRY. 



glycerophosphoric acid (perhaps also distearylglycerophosphoric 

 acid) we have large quantities of free phosphoric acid split off. 



GLYCEROPHOSPHORIC ACID (HO) 2 P0.0.0 3 H 5 (OH) 2 is a bibasic 

 -acid, which probably only occurs in the animal fluids and tissues 

 as splitting product of lecithin. The CHOLIN, which seems to be 

 identical with the bases SINKALIN (in mustard -seed) and AMANITIN 

 (inagaricus muscarius), has the formula HO. N(CH 3 ) 3 .C 2 H 4 .OH and 

 is therefore considered as trimethylethoxylium hydrate. Cholin ac- 

 cording to BEIEGER is not identical with the base, NEURIN, prepared 

 by LIEBREICH as a decomposition product from the brain, which is 

 considered as trimethylvinylium hydrate, HO.N(CH 3 ) 3 .C 2 H 3 . The 

 combination of cholin with hydrochloric acid gives with platinum 

 chloride a crystalline double combination which is easily soluble in 

 water, insoluble in alcohol and ether, and which crystallizes in six- 

 sided orange-colored plates. This combination is used in detecting 

 this base. 



Lecithin occurs, as HOPPE-SEYLER has especially shown, widely 

 diffused in the vegetable and animal kingdoms. According to this 

 investigator, it occurs also in many cases in combination with 

 other bodies, such as albuminous bodies, haemoglobin, and others. 

 Lecithin, according to HOPPE-SEYLER, is found in nearly all animal 

 and vegetable cells thus far studied, and also in nearly all fluids. 

 It is specially abundant in the brain, nerves, fish-eggs, yolk of the 

 -egg, electrical organs of the gymnotus electricus, semen and pus, 

 and also in the muscles and blood-corpuscles, blood-plasma, lymph, 

 milk, and bile, as well as in other animal juices and liquids. 

 Lecithin is also found in pathological tissues or liquids. 



Lecithin may be obtained in grains or warty masses composed 

 of small crystalline plates by strongly cooling its solution in 

 strong alcohol. In the dry state it has a waxy appearance, is 

 mouldable and soluble in alcohol, especially on heating (to 40-50 

 C.); it is less soluble in ether. It is dissolved also by chloroform, 

 carbon disulphide, benzol, and fatty oils. It swells in water to a 

 pasty mass which shows under the microscope slimy, oily drops 

 and threads, so-called myelin forms (see Chap. X). On warming 

 this swollen mass or the concentrated alcoholic solution, decom- 

 position takes place with the production of a brown color. On 

 allowing the solution or the swollen mass to stand, decomposition 



