678 
UREA IN THE URINARY SECRETIONS. 
ditions of the system the quantity of urea eliminated from the 
blood by the action of the kidneys, and excreted in the urine, 
is occasionally subject to great variation ; and some ready 
means of ascertaining its quantity in that secretion might 
frequently aid the physician in forming his diagnosis of certain 
diseases. 
Different means of effecting this object have, from time to 
time, been proposed ; but all the methods [hitherto recom- 
mended, with perhaps the exception of Baron Liebig’s recent 
one, require for their execution much time and trouble, and 
in some cases complicated and expensive apparatus, and 
though capable, in experienced hands, of yielding tolerably 
accurate results, would, in the case of those not much prac- 
tised in chemical manipulation, and perhaps unaware of the 
many sources of error to be guarded against, give anything 
but correct results ; and, therefore, inapplicable to the greater 
number of those desirous of a quick and easy method of 
determining the amount of urea in urine. 
The method I propose is one of extreme simplicity, and 
can be performed by almost any one in a very few minutes, 
and is capable of yielding results sufficiently accurate for all 
practical purposes. 
It is founded on the fact I have recently observed, that 
urea is very readily decomposed by the chlorides, or rather 
hypochlorites, of soda, potash, or lime, and that its consti- 
tuent nitrogen is evolved in the gaseous state, and from the 
quantity of gas evolved, I estimate the amount of urea present. 
After trying different means of carrying out this fact, with 
a view of making it available to determine the quantity of 
urea in urine, I found that the following very simple one 
seemed to answer the purpose completely. 
I take a glass tube, about twelve or fourteen inches long, 
closed at one end, and its open extremity ground smooth, and 
having the bore not larger than the thumb can conveniently 
cover. This I fill more than a third full of mercury, and 
afterwards pour in carefully a measured quantity of urine to 
be examined, which may be from a quarter of a drachm to a 
drachm, or upwards, according to the capacity of the tube ; 
then, holding the tube in one hand, near its open extremity, 
and having the thumb in readiness to cover the aperture, I 
quickly fill it completely full with a solution of the hypo- 
chlorite of soda (taking care not to overflow the tube), and 
then instantly cover the opening with the thumb tightly, and 
having rapidly inverted the tube once or twite to mix the 
urine with the hypochlorite, I finally open the tube under a 
saturated solution of common salt in water, contained in a 
