CHEMICAL BASIS OF THE ANIMAL BODY. 139 



dilute mineral acids, cerebrin yields a sugar which has recently been 

 shown to be identical with galactose. (See above p. 106.) 



Charcot's Crystals. 



These remarkable crystals, whose chemical nature and significance 

 have been the subject of much surmise, were first described by Charcot 1 

 in the spleen and blood of leukhaeinic patients. Later researches have 

 confirmed their characteristic appearance in this disease and have further 

 shown that they occur in health, more particularly in semen, but also 

 in various tissues 2 ; they are also found in asthmatic expectorations. 

 They may be readily obtained from semen by extracting with warm 

 water, to which a little ammonia has been added, the residue which 

 remains after semen has been treated with boiling alcohol. The 

 crystals separate out from this solution on concentration, and may 

 be purified, by recrystallisation. 



FIG. 6. CHARCOT'S CRYSTALS. (Krukenberg.) 



The crystals are insoluble in alcohol, ether and chloroform, slightly 

 soluble in cold and readily so in hot-water. Dilute acids and alkalis 

 also dissolve them readily. 



It has been stated that the crystals are in reality a compound of 

 phosphoric acid with a nitrogenous base to which the name spermin 3 

 has been given, and the formula C 2 H 5 N (1) has been assigned. This base 

 is obtained by the addition to the crystals of baryta water which forms 

 a phosphate of barium and liberates the base. It is soluble in water 

 and alcohol, yielding strongly alkaline solutions ; it may be reconverted 

 into Charcot's crystals by the action of phosphoric acid 3 . This base 

 was at one time regarded as closely related to, if not identical with 



1 Compt. Rend. Soc. Biol. 1853. Gaz. Hebd. 1860, p. 755. 



2 Zenker, Arch. f. Jclin. Med. Bd. xvm. (1876), S. 125. Schreiner, Ann. d. 

 Chem. u. Pharm. Bd. 194 (1878), S. 68. Cf. Maly's Jahresb. uber Thierchemie, 

 1878, S. 86. . 



3 Schreiner, loc. cit. 



