126 
SUGAR IN THE URINE OF THE HORSE. 
opinion of the older chemico-physiologists, through, 
firstly, the influence of the saliva on them, the ptyaline 
of which plays the part of a ferment, and induces a 
peculiar molecular transformation, which becomes perfected 
in the stomach. The modern theory of the formation of this 
glucose or grape sugar, however, is, that the liver is the great 
seat of the change effected on the non-nitrogenous or amy¬ 
laceous food, when substances termed hepatine and glucogen 
are produced, which are readily changed into sugar by the 
action of the saliva and the blood on them. Urea, the cha¬ 
racteristic principle in urine, is derived from the effete 
nitrogenized tissues. 
It has been said that sugar cannot be detected in the blood 
of diabetic patients, and therefore its formation must be re¬ 
ferred to other than the digestive process. Bouchardat, how¬ 
ever, avers that it may be found if it is sought for shortly 
after meals, and he refers its formation to a change produced 
among the amylaceous elements of the food, in which all 
writers concur. 
In the urine no difficulty presents itself—at least when the 
quantity is large—in the detection of sugar. It is only neces¬ 
sary to evaporate the suspected urine to the consistency of 
syrup and to leave it in a warm place for a little time, when 
crystals of this saccharine principle will soon be formed, 
which are to be washed in alcohol to abstract the colouring 
matter, and subsequently the granular mass may be purified 
b ) r resolution and crystallization. 
The late Dr. Golding Bird, writing on this subject, states 
that“themostextraordinary morbid change which urinesuffers 
is that connected with the formation of sugar in the disease 
called diabetes . This urine does not easily putrify, and may 
be made to undergo vinous fermentation ; it is- usually of a 
pale colour and more or less sweet to the taste, and its 
specific gravity is commonly above the healthy standard ; it 
is not, as is often supposed, destitute of, and even generally, 
I believe, not deficient in, urea. The presence of sugar in the 
urine is indicated by its tendency to ferment when in a warm 
place, especially on the addition of a little yeast. The influ¬ 
ence of sugar upon certain salts of copper may also be made 
available as a test in these cases. A few 7 drops of solution 
of sulphate of copper added to healthy urine occasion a 
slight blue cloud of phosphate of copper , and on adding a little 
potassa, hydrated oxide of copper is thrown down, which, if 
sugar be present, is redissolved by excess of potassa, forming 
a deep-blue solution ; and on heating the solution, the copper 
falls in the state of red suboxide; if there be no sugar, the 
