The decreases in blood pressure for all of the men in both Squads A and B, which were found for both systolic and diastolic pressures, as well as for the pulse pressure, indicate that one of the most pronounced effects of the reduced diet was upon the heart action. The fact that the diastolic pressure fell to 60 mm. or below in so many instances with both squads is surprising, for this is practically the so-called "shock level" observed in cases of surgical shock, which has been extensively studied in recent times in connection with the war. One might infer from this that with these extraordinarily low diastolic pressures the subjects would be distinctly unable to withstand surgical shock. On the other hand, we must bear in mind that this is simply another illustration of the marvelous capacity of the human body to adjust itself to very wide variations. While the safety factor may be very great, it would not necessarily follow that the diastolic pressure noted here would be so greatly affected by surgical shock as would a higher pressure. Indeed, the influence of surgical shock upon such low diastolic pressures as these would seem worthy of experimental study with lower animals.

Owing to other work it was impossible for us to give more specific attention to this important factor, but we feel that tracings should have been obtained and the data regarding blood pressure considerably amplified. In the absence of further information, adequate discussion of this subject is of course impossible. We must therefore content ourselves with recording accurately the data as obtained, in the hope that subsequent experimentation may amplify these and render a clear explanation possible. That these men at weight maintenance could have successfully and vigorously carried out their usual physical activities when the blood pressure was as low as is indicated in the series of observations recorded in tables 76 to 79, is one of the perplexing features of this whole research. The possibility of pronounced alterations in blood pressure in disease by means of dietetic alterations similar to those applied here opens a field for speculation which must first be thoroughly cleared by careful accumulation of experimental evidence. Diastolic blood pressures so close to the shock level as those observed with several of these men would imply that the dietetic conditions in this research might be somewhat near the border line of safety. Obviously, low blood pressure brought about by dietetic alterations must be thoroughly studied in all its phases before final deductions can be made.