But after a time, when the conditions under which the cells live and work are definitely unfavorable, they may fail to maintain the standard. Their performances become faulty or feeble, or, with their structure, may largely change. If carried beyond a certain limit, these weakened or perverted functions and their attendant physical changes constitute the condition called disease.
In fact, science does not now permit us to forget that "the living body is a mechanism, the proper working of which we term health; its disturbance, disease; its stoppage, death." The happy condition known as health does not commonly draw attention to itself, and so has escaped personification; while the other conditions disease and death, strictly its analogues from the earliest times have been invested with such mysteries as among all people have led to misconception and to figurative speech.
I wish especially to emphasize the simplicity of the modern scientific conception of disease as a disturbed condition of a complex cellular mechanism, because it is largely due to a failure to comprehend this that the shadows of the middle ages actually still lie dark over certain of the popular conceptions of medicine, and seriously retard the speedy fruition of many of its new discoveries.
The practical ends which have been of necessity held in view by the devotees to medicine, the bald empiricism through which most of the therapeutic resources of our art were won, and the stubborn persistence of old and misty conceptions of disease have greatly hindered the realization of the fact that medicine is, after all, only one phase of the great science of life which we call biology, and that its varied themes must be pursued by the same methods and under the same strict safeguards against error in observation and in inference as are current among those who study science in its simpler aspects. It may make some practical difference that the particular animal to which the medical man devotes his time is highly complex, fosters a soul, has a future, and pays in cash (sometimes) the expert who can relieve it from discomfort or pain and prolong for a little now and then the cellular confederation. But if we do not constantly draw light from the common sources, we shall wander hopelessly in empiricism and fail at last. In truth, to strive for wide comprehension of the human frame without the constant aid of sister sciences and frequent reference to simpler forms and functions is but to build upon the surfaces.
Permit me now in a somewhat desultory fashion to glance with you at two or three phases of recent development in medicine. I have not wished to frame an exhaustive inventory of our gains, but rather to note such features as can be led to wider be-
