FOODS HUMAN NUTKITION. 269 



"The better dijsrestion aud absorption of fat was probably due to any or all 

 of the following factors: (1) Increased secretion of gastric juice and, indei>end- 

 ently, of pancreatic juice; (2) increased acidity of the chyme bringing about 

 more active secretion of pancreatic juice aud bile; (3) increased i)eristalsis due 

 to larger volume of material in the intestine; (4) increased blood pressure due to 

 rapidly absorbed water; (5) more complete hydrolysis by lipase because of 

 increased dilution." 



The efCects of various forms of exercise on systolic, diastolic, and pulse 

 pressures and pulse rate, O. S. Lowsi.ev (Amcr. Jour. I'liy.siol., 27 (19 LI), 

 No. 5, pp. .'/Jfij-'ibG, dgins. 5). — In the investigations reported the author has 

 studied the effect on the heart of diftorent kinds of exercise. 



Quotations from his conclusions follow: 



" Pulse rate, which always increases during exercise, decreases rapidly after 

 its completion. This drop in the curve of the pulse rate is frequently followed 

 by a secondary rise which is possibly a reflex effect due to the low blood pres- 

 sure of the subnormal stage. In no case was it observed that this secondary 

 rise was accompanied by a rise in blood pressure. 



"Rapid exercises (vigorous, fatiguing, and exhausting) are followed by a 

 fall of pressure below normal which lasts longer than after moderate exercise, 

 even if the former is continued for a very short period and the latter for quite 

 a long period of time. If we consider the subnormal phase as indicative of an 

 overstrain following upon the great reflex excitation of the heart and vaso- 

 motor center, then it would seem that after these so-called rapid exercises the 

 strain is more serious, as is shown by the much longer time required before the 

 conditions return to their normal level. 



" If our interpretation of the subnormal phase is correct, it would follow that 

 the so-calleil field events, consisting of jumping, shot putting, discus and hammer 

 throwing, and baseball, gj-mnasium api)aratus work, aud exercises of a similar 

 nature, are preferable to rapid exercises, such as basket ball, football, and run- 

 ning races. This is particularly true in the case of the rapidly growing youth, 

 whose heart is under the additional demand of keeping pace with an increase in 

 the tissue mass of the body. 



"There is less strain put upon the circulatory system by walking a number of 

 miles at a moderate rate than by sprinting 100 yards at top speed. This con- 

 clusion follows from the fact that blood pressure returns to normal after mod- 

 erate exercise in about 30 minutes, while after short sprints the subnormal stage 

 continues about three times as long. 



" Long-distance running races and similar forms of exhaustive exercise give 

 rise to a serious strain on the heart, as is indicated by the long period of sub- 

 normal blood pressure. 



" It would soem probable that in individual cases the beneficial or injurious 

 effect of any given form or amount of exercise might be determined bj^ observa- 

 tions upon the subnormal phase following the exercise. When the subnormal 

 phase returns to normal within 60 minutes, the exercise may be considered as 

 lying well within hygienic limits for that individual, while a return that is 

 delayed beyond 120 minutes may be regarded as exceeding these limits." 



Law of the body expenditure following' work, J. Amar {Compt. Rend. Acad. 

 Sci. [Paris], 151 {1910), No. 21, pp. 952-95-^). — The author has studied the rate 

 of recovery after exercise in experiments with man. The exercise was per- 

 formed on a bicycle ergometer, and the respiratory exchange was determined. 

 He believed that the oxygen consumption may be regarded as a measure of the 

 body expenditure and that the changes after work should follow Newton's laws 

 for cooling bodies, but, as was shown by experimental evidence, such was not 

 the case. 



