340 ON HIPPURIC AC 
BENZOIC ACID. 
Crystallizes in hexagonal 
needles, or in white, diapha- 
nous, pearly, flexible laminae. 
Is soluble in two parts of 
ether. 
Is not changed by dilute 
nitric acid. 
Heated with three times its 
weight of hydrate of lime, ge- 
nerates simply benzole. 
) AND ITS TESTS. 
HIPPURIC ACID.* 
Crystallizes in four-sided 
prisms with dehedral sum- 
mits. 
Is very sparingly soluble in 
ether. 
Treated with dilute nitric 
acid, and evaporated to dry- 
ness, produces, on the addi- 
tion of ammonia, a beautiful 
purple color. 
Heated with three times 
its weight of hydrate of lime 
disengages a quantity of am- 
monia. 
BENZOATE OF AMMONIA. 
On being exposed to a 
strong heat, melts and flies off 
in benzoic acid fumes, with- 
out leaving any appreciable 
residuum. 
HIPPURATE OP AMMONIA. 
Exposed to heat, melts and 
assumes a rose-red color form- 
ing a reddish acid ; which 
being dissolved in water and 
evaporated, affords red crys- 
tals, resembling hippuric acid 
in their properties. 
BENZOATE OF POTASH. HIPPURATE OF POTASH 
Burns without emitting any Heated so as to undergo de- 
particular aromatic odor. composition, exhales the' odor 
of bitter almonds. 
On the whole sulphuric ether furnishes the readiest test for 
distinguishing these two acids, from the easy solubility of the 
one, and the difficult solubility of the other in that menstruum. 
Pharmaceutical Transactions. 
♦The verifications were all made with hippuric acid derived from the 
human subject. 
