This section is from the book "The Human Body: An Elementary Text-Book Of Anatomy, Physiology, And Hygiene", by H. Newell Martin. Also available from Amazon: The Human Body.
From the division of employments in advanced communities, several important consequences result. In the first place, when every one devotes his time mainly to one kind of work, all kinds of work are better done : the man who always makes boots becomes much more expert than the man who is engaged on other things also : he can not only make more boots in a given time, but he can make better boots; and so in other cases. In the second place, when various employments are distributed among different persons there arises a necessity for a new kind of industry in order to convey that part of the special produce of any given individual which may be in excess of the needs of himself and his family to others who may want it, and to bring him in return such of their excess production as he may need. The conveyance of food from the country to cities, and of manufactures to agricultural districts, are examples of this sort of labor in civilized communities. Finally, there is developed a necessity for arrangements by which, at any given time, the activity of individuals shall be regulated in accordance with the wants of the whole community or of the world at large. This sort of regulation is still very imperfectly carried out even in the most advanced communities, and we accordingly hear from time to time of the over-production of this or that article ; but it is in part effected through the agency of capitalists who control the activities of many individuals in accordance with what they think to be the quantity of various articles likely to be required from time to time.
What do we find all cells doing in the lowest animals? How do higher animals differ in this respect?
How does a division of labor influence the quantity of work done by a man? How the quality? Illustrate. What new kinds of employment arise when a division of labor becomes developed in a nation ? Illustrate.
Exactly similar phenomena result from the division of physiological labor in the human body. Each tissue and organ doing one special work for the whole body, and relying on the others for their aid in turn, every sort of necessary work is better performed; the tissue or organ, having nothing else to look after, is constructed with reference only to its own particular duty, and is capable of doing it extremely well. This, however, necessitates a distributing mechanism by which the excess products, if any, of the various organs, shall be carried to others which require them; and a regulating mechanism by which the activities of each shall be controlled in accordance with the needs of the whole body at the time being. We accordingly find a set of organs, the heart and blood-vessels, which carry blood from place to place all over the body, the blood getting in its course something from and giving something to each organ it flows through; and a set of nervous organs which ramify in every direction and regulate the activity of all the more important parts.