The food must be digested, absorbed and excreted with great rapidity.
As it is largely excreted by the lungs it may be found useful in bronchial asthma.
The protoplasm derives its food from substances in solution in the water; the various waste products which are incident to its life are excreted into it, and so removed from the sphere of its activity.
The drug circulates in the blood in the form of an albuminate and is slowly excreted by the kidneys.
Waste products which are not excreted by the kidneys are removed from the blood by the liver.
