THE BODILY MECHANISM
The body of a human being is made up of a vast number of cells, together with certain structures and fluids manufactured by certain groups of these cells. Among these manufactured products are bone, cartilage, hair, nails, the lymph and the plasma of the blood. The cells are living; the structures and fluids mentioned are non-living, but are essential to the life of the body, and the life of its cells.
The relations between the cells and the cell-products which make up the body are strikingly like those existing in a swarm of bees. The bone, hair, lymph and other non-living parts of the body may be likened to the combs, honey, and bee bread: the individual cells to the bees. Each cell in the body is a distinct, living individual: it could, if proper conditions of food, moisture and temperature were supplied, remain alive and even grow, although isolated from the other cells. In fact, cells from lower animals have been kept alive, and have thrived, in artificial cultures. So a bee may live when separated from the swarm.
Under ordinary conditions, however, the life of the bee depends upon its being a part of a swarm; and the life of a cell depends upon its being a part of an animal body. The swarm is made up of groups of individuals having functions which are contributory to the life of the whole swarm, although no one group performs all the necessary functions. The queen, after fertilization, deposits eggs in cells prepared by the workers and does nothing else, except maintain her own vital functions. Certain workers care for the eggs and larvae; others gather honey or pollen; others prepare the "bee bread;" and others make and care for the comb. The labor of each group so supplements the labor of the others that the total functions necessary for the life of the swarm are accomplished.
In a similar, but more highly specialized way, the various