eluded: I‘. . . vasoconstriction, decrease in blood flow rate and fre- quency of plasma spacing, blocking of blood flow in varying num- bers of nutritive capillaries, shunting of blood from arterioles to venules

quency of plasma spacing, blocking of blood flow in varying numbers of nutritive capillaries, shunting of blood from arterioles to venules . . . . ” These microcirculatory changes were said to result in a decrease of nutritive blood flow in tissue. As mentioned in the discussion of CHD, Kjeldsen ( 31, 32) studied several smoking patients with occlusive peripheral vascular disease whose COHb levels were significantly higher than those of control smokers. The levels of COHb in many of these patients were comparable to those associated with experimental atherosclerosis in animals. Astrup, et al. (4) have suggested that prospective studies should be performed to investigate the relationship between COHb levels and the incidence of arterial disease. In the Prague study (19) intermittent claudication was significantly (P < .Ol ) more common among cigarette smokers than nonsmokers. Twenty percent of the men in the age group of 60 to 64 who were heavy smokers (more than 25 cigarettes a day) had intermittent claudication. Riif (44) reported that all but 4 of the 98 patients admitted for peripheral vascular surgery at the Karoline Hospital, Sweden, were smokers. Mathiesen, et al. (38) in Denmark followed the spontaneous course of arterial insufficiency in 211 patients. Cessation of smoking increased the number of patients displaying spontaneous improvement.