THE 
VOL, XXXIV. 
No. 399. 
MARCH, 1861. 
Fourth Series. 
No. 75. 
Communications and Cases. 
ON SUGAR IN THE URINE OF THE HORSE. 
It is an interesting fact, and one which has not received 
all the inquiry it merits, that very rarely is sugar found in 
the urine of the horse. Only an isolated instance or two have 
been placed on record, and these being considered exceptional 
cases, it is commonly said that this animal is not the subject 
of diabetes mellifus , or of that conditional state of the urine in 
which the saccharine principle exists in it, but only of the other 
variety of the disease, designated diabetes insipidus , polyuria , 
&c., in which the secretion is in greatly increased quantities, 
but retains its natural taste. Nevertheless, from such urine 
a substance has been obtained by M. Thenard resembling 
sugar in its being capable of furnishing alcohol by fermenta¬ 
tion, and becoming changed into grape sugar by the action 
of dilute sulphuric acid on it: still, it does not possess a 
sweet taste. This statement, however, it appears, requires 
confirmation. According to Berzelius, “ the urine in 
diabetes insipidus , though not sweet, is excessive in quantity 
and deranged as to composition; the formation of urea is 
suspended, and such always leaves, on evaporation, a brown 
residue, of the consistence of syrup, from which nothing 
crystallizes, and which is slightly acid.' 5 
It might have been anticipated, from the nature of the food 
of the horse, that he would have been far more frequently 
affected with the first-named form of this disease than with 
the latter ; at least, such would have been the inference, 
reasoning a priori , since it is taught that farinaceous and 
other allied matters become converted into sugar during 
digestion ; the change beginning in the mouth, in the 
xxxiv. JO 
