EXCRETION 
457 
flushed skin, a feeling of warmth, and a false feeling of in¬ 
creased circulation. Its result is to send more blood through 
the skin with consequent extra loss of heat. This action 
is evidently not due to stimulation, but to the relaxation of 
the muscles, and is thus a decrease of activity rather than an 
increase, even though the blood does flow a little more rapidly 
through the skin. These facts make it clear that alcohol 
cannot be properly called 
a stimulant of the circula¬ 
tory system.”— Conn and 
Buddington. 
358. Excretion. — Every 
animal uses energy in carry¬ 
ing on its work. During 
this process a certain amount 
of waste substance is pro¬ 
duced, which has to be re¬ 
moved from the body. The 
skin, kidneys, and lungs are 
the chief organs which assist 
the body in getting rid of 
this waste. When any part 
of the living cells is broken 
down in the simple act of 
living, a waste product re- Figure 407 . —Longitudinal Section 
suits. By osmosis these 
waste products enter the blood and are removed by the 
lungs, which give off carbon dioxide, by the sweat glands 
in the skin, and by the kidneys, which remove the wastes 
that contain nitrogen. The sweat glands and kidneys are 
usually regarded as the excretory organs of man. These 
organs remove from the blood the wastes which have been 
excreted by the cells of the body. The excretion from the 
living cells is one of the fundamental life processes of all 
plants and animals. This form of excretion should not be 
