generalizations which serve as guideposts to other discoveries.


BICHAT AND THE BODILY TISSUES

Much the same thing may be said of another generalization
regarding the animal body, which the brilliant young French
physician Marie Francois Bichat made in calling attention to the
fact that each vertebrate organism, including man, has really two
quite different sets of organs--one set under volitional control,
and serving the end of locomotion, the other removed from
volitional control, and serving the ends of the "vital processes"
of digestion, assimilation, and the like. He called these sets of
organs the animal system and the organic system, respectively.
The division thus pointed out was not quite new, for Grimaud,
professor of physiology in the University of Montpellier, had
earlier made what was substantially the same classification of
the functions into "internal or digestive and external or
locomotive"; but it was Bichat's exposition that gave currency to
the idea.

Far more important, however, was another classification which
Bichat put forward in his work on anatomy, published just at the
beginning of the last century. This was the division of all
animal structures into what Bichat called tissues, and the
pointing out that there are really only a few kinds of these in
the body, making up all the diverse organs. Thus muscular organs
form one system; membranous organs another; glandular organs a
third; the vascular mechanism a fourth, and so on. The
distinction is so obvious that it seems rather difficult to