The vascular disorders grouped under the name of arteriosclerosis are becoming increasingly more important from the medical, social and economic point of view as a result of the growing proportion of older people in the population. In addition, the increasing concentration of the population in urban industrial areas has led to greater contact with factors which tend to promote this condition. Hueper1 has published recently a series of papers reviewing this subject. As arteriosclerosis seemed to be a natural sequence of aging, senescence was early looked on as a causative factor in this condition, a view which, according to Heuper, was responsible for the stagnation in its investigation. This theory has been discarded by most investigators, since appreciable arteriosclerosis is not a constant phenomenon of old age. For any age group definite relation between the degree and distribution of senile vascular changes and arteriosclerotic changes has not been established.