B. R. Hooker1 shows, in his reports of respiratory cases, that placing patients in the open air increased the bloodpressure from 5 to 10 mm. Influence of Climate.-Weston P. Chamberlain has recently reported in the Philippine Journal of Science2 an exhaustive study of the effect of climate and race upon the normal average blood-pressure readings. The study is based upon 6128 blood-pressure observations on 1042 white men and 552 Filipinos all in good health and ranging in age from twenty to forty years. The average systolic pressure of 5368 readings on 992 persons, was 115.6 mm. and the pulse rate taken simultaneously averaged 81 beats per minute. The average age was 26.6 years. Comparing this average with that of Woley (see page 42) Chamberlain's Table.-Average systolic blood-pressures and pulse rates, based on 5368 observations of each which were made on 992 American soldiers serving in the Philippines; arranged according to age. (12.5cm. armlet.) it is found to be 7 mm. lower and compared to Bachman1 3 mm. lower. While the pulse rate in Chamberlain's series was 9 beats per minute above the average accepted as normal in temperate climates for all ages. He also found that the blood-pressure has a tendency to be lower than the averages given above, during the first three months stay in tropical climates. Racial Influence on Blood-pressure.-Chamberlain also reported2 a series of observations conducted to determine the effect of race upon average systolic blood-pressure and obtained the following result: Average blood-pressure of 100 Filipino scouts, 115.0 Average blood-pressure of 100 Philippine soldiers, 115.9 and states that "we may, therefore, conclude that the mean blood-pressure for Filipinos of from fifteen to forty years of age (average age twenty-five years) is 115 to 116 mm. and that it does not differ from the pressure at the same age for Americans residing in the Philippines." Normal Blood-pressure Studies in the American Indian. -The investigations of Dr. Harley Stamp who was attached to an archæological exposition sent out by the University of Pennsylvania headed by Dr. Frank G. Speck, have brought out some very interesting points in connection with the comparative study of blood-pressure. These observations for the most part were carried on in the winter of 1913-14 to the number of many thousand upon fifty-seven tribes of American Indians, and often at from 20° to 30° below zero. Another group of the observations 1 N. Y. Med. Jour., 1911. 2 Loc. cit. was made at the Carlisle Indian School, thereby giving some comparative data as to the effect of civilization upon blood-pressure in the American aborigine. In summarizing these observations it may be said that the effects of exercise probably subside more quickly in the Caucasian than in the American Indian. "The effects of low temperatures were undoubtedly very noticeable; the effects also of the habits, not only in reference to their food but also to the lack of sanitary requirements, even of the most primitive kind." These observations were all made by accepting the first point as the systolic and the fifth point as the diastolic pressure criterion. The individual ages ran from two months to 103 years, and the Indians were of all sizes, the same as found in any Caucasian community. There were among them approximately the same proportion of good muscular development. The diurnal and periodic changes showed no differences from similar observations upon Caucasians, while emotion causes a far greater variation in the Indian than in his white brother. This investigator is inclined to believe that the individual inclines to become acclimated to low temperatures, which causes the variation to become less as the low temperatures are endured. There was no difference noted in the effect of postural changes, or of alcoholic indulgence. In the use of tobacco there is a marked difference in the effect on the two peoples. This seems to be due to excessive smoking and to the use of "doped" tobacco by the Indian. Much of this is taken in the form of snuff. The tea habit seems well formed and the record is made of a guide who drank forty-two cups of strong tea a day. The normal age charts of blood-pressure records upon the American Indian differ but slightly from those of the white except that there seems to be a uniform tendency to reduced blood-pressure at or about the forty-fifth year. CHAPTER X PHYSICAL FITNESS, EXERCISE AND ATHLETICS BLOOD-PRESSURE General Considerations.-The physiology and pathology of exercise are chapters in medicine, which have just begun and in which there is much to be written. A number of facts, however, have been established which permit of certain generalizations, this being particularly true of our knowledge of the response of the heart to changes in the circulation induced by muscular activity, and it is generally recognized that no one should be permitted to engage in exhausting sports or unusual physical exertion, who does not possess an effective cardiovascular system, which will insure him against possible untoward results from the extraordinary effort. Thus we find that a careful and thorough physical examination, with special reference to the condition of the heart, circulation and kidneys made by a competent medical examiner, has become a recognized practice in most gymnasia and athletic institutions, where youths train and engage in competitive athletics. The indulgence in athletics as a means of preserving health and physical well-being, and the rational employment of special exercises as one of the devices of physical therapy now demand of the active physician a comprehensive under |