The study of disease in the human being is always rendered difficult by the fact that the pathologic investigations, for the most part, must be limited to the terminal stages of the disease. Such studies, while they doubtless advance our knowledge to a large extent, throw little light on a very essential aspect of the subject, the evolution of the disease. In man we must depend for our studies of the early stages of most chronic diseases on the chance finding of early lesions in subjects dead of other conditions. Even here the pathologic conditions may be so various that their inter-relations are difficult of interpretation, and we are finally reduced to the experimental method if we are to follow a given disease, uncomplicated, throughout its course.
Arteriosclerosis is a disease so common and so varied in its effects that it has always been subjected to close study and numerous