33S 
ON HIPPURIC ACID AND ITS TESTS. 
bility. Thus hippurate of soda requires about two parts of 
water at 90° Fahr. to dissolve it, whereas the corresponding 
uric salt, which constitutes, as it is well known, the gouty 
concretions or chalk stones, is acknowledged to be nearly as 
insoluble as uric acid; it requires at least 4000 parts of water 
to dissolve one. Hippurate of ammonia again is but little 
less soluble than hippurate of soda, while urate of ammonia 
will only dissolve to the amount of l-480th part. Hippurate 
of lime, the least soluble of these salts examined by me, re- 
quires IS parts of water to dissolve one. 
The application of the above principle has proved of mate- 
rial benefit in the treatment of certain unhealthy conditions 
of the urine, occurring in subjects of a calculous or gouty 
diathesis ; since it enables the practitioner to obviate entirely 
the various depositions resulting from excess of uric acid, the 
fruitful source of that most distressing malady, stone in the 
bladder ; as also to controul and prevent the formation of 
the so called tophaceous concretions or chalk stones, w T hich 
occasion so much inconvenience, deformity, and pain to in- 
dividuals laboring under gout. 
By judicious exhibition of the benzoic acid, or, according 
to particular circumstances of a benzoic salt, that is to say 
apportioning the dose to the state of the renal secretion, best 
previously ascertained by analysis, we can fulfil the desired 
indication with unerring precision, and that, as shown in 
the above paper, without any risk of affecting the general 
health, or of irritating the urinary organs. 
It is to be kept in mind that this plan of treatment by no 
means precludes the adoption of other suitable remedial mea- 
sures. Of course certain rules of diet must be observed, 
which there is no necessity for referring to here. It would be 
equally irrelevant to occupy your time with the details of 
cases, several of which have lately come under my notice, 
and go to corroborate the statements above made. 
As benzoic acid is apt to irritate the fauces, unless adminis- 
tered in a liquid state, and as it needs a large quantity of water 
