CHEMICAL BASIS OF THK ANIMAL P.nPY. 187 



Its constitution is further characteristically shown \>y it- pro- 

 duct i. .a hy the action of ben/amide on monochlor-ftoetio acid : 



C 6 H 6 .CO . NH 2 +CH S C1 . COOH=C.H, . o > N 1 1 < ' 1 1 _.. a x )H.+ 1 1 ; 



ami al.-o by that of benzoyl-chloride on glycin : 1 

 C.H6.CO.C1+CH, (NH,) . COOH=C,H 5 . < M I .CH 8 .CO( > II +11 < 1 

 It may be readily obtained from tin- urine of horses or co\\ -. 

 more particularly when they are out to ^rass, t\\e perfect It/ / 

 urine hoileil with milk of lime in slight excess, by which means 

 the arid U tixe.l as a hippurate of calcium. It i> then tilteivd. the 

 filtrate concentrated to a email bulk ami treated when cold with 

 hydrochloric acid in slight excess; this decompo>es the calcium 

 salt, litteratinu hippuric- acid, whii.'h separates out at once, owiiiL; 

 to its comparatively slight soluliility. It is then puritied liy > 

 recrystallisations from boiling water, but it is extremely dithVult 

 to obtain it colourless. 



II. Hn-i'i i:i \. ii. CRTSTALS. (After Kunke.) 



When rapidly separated out from its aqueous solutions, a 



the above met hod of its j. reparation, it assumes the form of tine 

 needle-. I ',y >lo\vi-r cry-t a 1 lisat ion it yield- hmx foursided pri-m- 

 or cnlumns with ]i\ ramidal ends; the-e are frequently arranged 



>ups and present a semitran-pnrent. milky appearance. 

 When ] Hi re they are odourles- and of a somewhat hitter taste. 

 They rei|iiire <i(M> parts of water for their -olution at 0, arc' 

 readily >oluble in hot wat--r, al-o in alcohol anil to a nt in 



ether. They are conveniently insoluble in petroleum-ether, in 

 virtue of which hippuric acid can be readily separated from hcn/oic 

 acid which is soluble in this reagent. Its solutions redden litmu-- 

 paper. 



1 Baum. Zt.f. /%- !' I ix. (!.".')). S. 4f,:, 



8 To avoid fermentative .lci..in|>.)!itiun int.. Iwn/ui.- a. j,| ntnl gl\-\ -in. 



