- 19 Comments: Here the author assumes that atherosclerotic plaques are the result of alpha radiation induced eell mutations and suggests that the alpha emitters responsible originate from the lung (presumably inhaled) because the pulmonary arteries rarely develop atherosclerotic plaques. This would imply that inhaled alpha emitters that get into the blood are trapped efficiently in their first passage in the blood stream through the pulmonary veins, heart, coronary arteries, and perheps the rest. of the vascular tree except that virtually none is left in the blood by the time the blood reaches and services the pulmonary artery. The author does not discuss this matter, or the fate of alpha emitters absorbed from the gastrointestinal tract, or the mechanisms by which alpha emitters may be taken up so specially in aorta, coronary arteries, ett, on the first passage of the blood containing them. The sentences which are the subject of these comments represent a very poor argument for the respiratory origin of the causative agent, for the nature of the causative agent, or for the reason for the rarity of ‘atherosclerosis in the pulmonary artery. It is highly unlikely that there would be no alpha emitters passing through the blood of the pulmonary artery or of its vasa vasorum after inhalation and ingestion of alpha emitters that were in a state allowing them to pass into the blood. Page 11, lines 8-10 - "Attempts to reproduce arterial lesions in animals by chemical, mechanical and nutritional means have not produced plaques similar to those of atherosclerosis in man ym