The present study was undertaken with the primary objective of developing data which might throw further light on our understanding of the production of arteriosclerosis. It was appreciated that certain other facts of interest might be uncovered as the investigation progressed. Although years of study by numerous workers have been devoted to this great enigma of biology, it can be fairly stated that today it is not known whether arteriosclerosis should be considered as a disease or as a purely degenerative process. The fundamental importance of diet, climate, infection, metabolism, race, heredity and many other factors is yet to be finally evaluated. Age alone does not appear to be responsible, since arteriosclerosis may be present in some persons at 30 years or less, whereas others may show practically none at the age of 70. A popular hypothesis has been that arteriosclerosis is related to prolonged stress and strain on the