394 KENNEL DISEASES. 
in instituting it. The work must be slow and easy at first. As fat is with- 
drawn from the heart it is left soft and flabby, and were hard runs encouraged 
the result might be heart-failure. Therefore, in the beginning, walking should 
be the exercise, and the distance steadily increased daily. Then short easy 
runs for a time; and finally, as the dogs come into condition, harder and faster 
work can be allowed without danger of harmful results. 
DIABETES MELLITUS. 
Diabetes mellitus is a disease characterized by the appearance of a large 
amount of sugar in the blood and urine, and progressive loss of flesh and 
strength. 
The true nature of this affection is still undetermined. The microbic 
theory has been advanced, and has some supporters. The disease has also 
been variously attributed to abnormalities in the pancreas, liver, kidneys, and 
process of digestion; which theories are much too complex for discussion 
herein. Then there is the very simple and comprehensive theory that it is due 
to partial paralysis of certain nerves going to the liver. 
Sugar is one of the natural constituents of the blood, and the same is de- 
rived partly from the food —the starches being converted into sugar while in 
the intestinal canal,— and partly from the liver, which contains a material, 
manufactured in that organ from animal as well as vegetable substances, that 
is transformed into sugar on absorption into the blood. In health some of this 
sugar goes to nourish the body; some, also, is devoted to other purposes, of 
which as yet but little is known. But if sugar is formed in excess or is not 
rightly disposed of, it accumulates in the blood, where it acts as any unusual 
ingredient would, and is thrown out by the kidneys, together with a large 
quantity of water, which is necessary to hold it in solution. 
Strictly speaking, therefore, diabetes is really a blood disorder occasioned 
by sugar; and it may be even rightly termed blood-poisoning from the same. 
It is fortunately only rarely encountered in dogs, hence but little is known 
of the predisposing causes. There seems, however, good grounds for the 
belief that when attacking them it is usually attributable to injuries of the brain 
or spinal cord, especially the former; and that it has a preference for dogs of 
advanced age, in whom such injuries are most serious because of their low 
reparative powers. 
The symptoms are evolved slowly and gradually, and the disease may be 
present for a long time before they become sufficiently pronounced to attract 
attention. 
A change in demeanor is generally the first evidence noted, and it may be 
