FUNDAMENTAL PRINCIPLES OF DISEASE. 87 
or on the legs, as so often used. Blisters, iodin, and many other 
irritants are used in a similar way. 
Constitutional treatment in inflammation is designed to reduce the 
current of blood, which is the fuel for the inflammation in the dis- 
eased part, to quiet the patient, and to combat the fever or general 
effects of the trouble in the system, and to favor the neutralization or 
elimination of the products of the inflammation. 
Reduction of blood is obtained in various ways. The diminution 
of the quantity of the blood lessens the amount of pressure on the 
vessels, and, as a sequel, the volume of it which is carried to the point 
of inflammation; it diminishes the body temperature or fever; it 
numbs the nervous system, which plays an important part as a con- 
ductor of irritation in diseases. 
Blood-letting is the most rapid means, and frequently acts like a 
charm in relieving a commencing inflammatory trouble. One must 
remember, however, that the strength of the body and repair depend 
on the blood; hence blood-letting should be practiced only in full- 
blooded, well-nourished animals and in the early stages of the 
disease. 
Cathartics act by drawing off a large quantity of fluid from the 
blood through the intestines, and have the advantage over the last 
remedy of removing only the watery and not the formed elements 
from the circulation. The blood cells remain, leaving the blood as 
rich as it was before. Again, the glands of the intestines are stimu- 
lated to excrete much waste matter and other deleterious material 
which may be acting as a poison in the blood. 
Diuretics operate through the kidneys in the same way. 
Diaphoretics aid depletion of the blood by pouring water in the 
form of sweat from the surface of the skin and stimulating the dis- 
charge of waste material out of its glands, which has the same effect 
on the blood pressure. 
Antipyretics are remedies to reduce the temperature. This may be 
accomplished by depressing the center in the brain that controls heat 
production. Some coal-tar products are very effective in this way, 
but they have the disadvantage of depressing the heart, which should 
always be kept as strong as possible. If they are used it must be with 
‘knowledge of this fact, and it is well to give heart tonics or stimu- 
lants with them. The temperature of the body may be lowered by 
cold packs or by showering with cold water. This is a most useful 
procedure in many diseases. 
Depressants are drugs which act on the heart. They slow or 
weaken the action of this organ and reduce the quantity and force 
of the current of the blood which is carried to the point of local 
disease; they lessen the vitality of the animal, and for this reason 
are now used much less than formerly. 
