Page:Popular Science Monthly Volume 36.djvu/555

Rh any condition of the mucus of the pharynx. It is caused by the exhaustion of the watery elements of the blood. It is therefore removable by injections of water, and by bathing, when water is absorbed by the pores.

If hunger is not satisfied, it disappears after a certain length of time. The most intense suffering is endured during the first twenty-four hours, after which the pain diminishes. The characteristic phenomenon exhibited by an animal subjected to starvation is the constant diminution of weight. I have made many experiments on this loss, comparing animals of various sizes, and have determined that the function of dehydration—or reduction of weight—is in direct relation with the size of the animal; and I believe that I can deduce a great rule of comparative physiology that the activity and intensity of all the functions are determined by size. Carnivorous animals appear to bear fasting better than herbivorous kinds. The latter eat nearly all the time, and are ill when they have to stop; but carnivorous animals, in the wild state, are often forced to endure abstentions of considerable length; and a fast of several days is almost a physiological condition with them.

When we examine the phases of the loss of weight of a starving animal, we find that it loses much during the first days. Then a moderate drain sets in. Again, in the last days considerable loss takes place, and this is the forerunner of death.

Cold-blooded animals can support inanition during a prodigiously long time. M. Vaillant has told me of a python weighing seventy kilogrammes that lived twenty-three months without eating; M. Colin, of a rattlesnake that lived twenty-nine months. Redi mentions a tortoise that lived eighteen months, and a frog sixteen months, without food. When we have frogs in our aquariums waiting to be experimented upon, we never feed them and they never starve. Dogs can endure abstinence, on the average, of thirty days; cold-blooded animals, twice as long. They are capable of this, because their tissues are consumed more slowly, and do not require so frequent renewing. With both classes the fatal limit is reached when the loss of weight amounts to forty per cent. This point is reached by the warm-blooded animal ten times as quickly as by the cold-blooded one, because its nervous system is ten times as active. The relation of the nervous system to the intensity of the chemical exchanges of vital action is shown by the existence of hibernating animals, or warm-blooded animals which periodically become cold-blooded. Becoming torpid at the approach of the cold season, their breathing and circulation become slow, their motions weaker, their eyelids close, they fall into their winter sleep, and their temperature descends to about 40° Fahr.