Page:Popular Science Monthly Volume 48.djvu/394

362 the separate parts of the human frame. And it was not until the early decades of the present century that science was able to declare the ultimate element out of which all these varied parts are built to be a tiny particle of living matter which was called a cell.

Somebody has said of Turner that he was a man who thought in paint. The modern devotee to medicine, if he seriously thinks at all, must think in cells. Physicians used to think in symptoms, and it took them a great many years to learn that they must think also in cells and organs—that is, with clear morphological conceptions—if they would crystallize for use the knowledge which experience brought them.

Through the long processes of evolution, these cells have acquired peculiar forms, and adapted themselves to the performance of special functions. The great cell groups—we call them liver, lung, brain, muscle, bone—each doing its particular work, all act in harmony for the maintenance of the life and performance of the body as an independent being.

We do not yet understand, nor shall we soon, what that marvelous vivifying influence is which sets this self-built cellular mechanism at work, and keeps it going, as a rule, under favorable conditions until the shadows of threescore years and ten begin to deepen about the worn machine. Nor has all our gathered life lore led us far among the mysteries which cluster about the vague region in which the spiritual and the material meet and interfuse. But this we know, that all the things the body does, from its high borderland achievements in thought and memory down through the homely processes of nutrition and repair, are accomplished by these small life units in accordance with physical laws as definite and unvarying as are those which we trace in plant and earth and star.

Under a variety of adverse conditions the human body can still hold its own and secure for a time a certain degree of health, thanks to the adaptability to circumstances of its component cells. Thus, by the nice control of its ceaseless chemical processes, the body can maintain a nearly uniform degree of heat, no matter what the latitude or season. Starve the body, and its cells can feed for a while upon the stores which they have in times of plenty laid aside. They struggle long and faithfully against the manifold excesses which may be forced upon them. They fight with fashion, in one sex at least, for space within this none too roomy tabernacle, with business and with pleasure for a time to rest, with drugs and blighting drinks and unwholesome foods for release from poisons which it is not usually thought criminal to administer to one's self. They work as best they can without the wholesome air so frequently denied them. They resist with what force they can muster inherited weaknesses or taints.