FOODS HUM\N NUTRITION. 865 



with the respiration calorinioter and accessory appliances, together with obser- 

 vations of body weight, body temperature, pulse and respiration rate, strengtli 

 tests, and blood exannnations. The respiratory exchange and the heat output 

 were subjects of special study. Experiments during prolonged fasting were 

 included to note fluctuations from day to day and a series of 2-day fasts with 

 a number of men was carried on to eliminate the influence of individualit.v. 

 In the longer experiments the subject was a young man, who claimed some 

 previous experience In fasting and in the remainder the subjects were college 

 students. The results are sunmiarized and discussed in detail. 



In general, the fluctuations in body weight were very considerable, not only 

 from day to day in a given experiment, but in experiments with different sub- 

 jects and in different experiments with the same subject. As shown by data 

 for the quantities of protein, fat,*and glycogen katabolized on different days 

 during the fasting period, it was evident that while there may be marked 

 fluctuations in the loss in body weight these fluctuations in practically all 

 instances must be due to the quantity of water consumed and urine excreted. 

 The actual daily loss in weight was found to vary fi'om 44 gm. to 1.7 kg. 



Body temperature undergoes normal, rhythmical fluctuations. The obser- 

 vations on fasting subjects showed that in general the fluctuations were much 

 smaller during inanition than when food is taken. 



Important deductions were drawn from the studies of the effects of fasting 

 upon the blood. A progressive average fall in the number of erythrocytes was 

 noted during inanition with recuperation following. A corresponding dimi- 

 nution in the percentage of hemoglobin was also noted. In the prolonged fast 

 a relative progressive fall in the percentage of leucocytes was observed but no 

 remarkable effect of fasting on the relative percentages of the various types 

 of leucocytes was noted. A high percentage of polymorjjhonuclear leucocytes 

 observed during the fasts is explained by the relative leucocytosis. 



The common assumption is that as fasting progresses strength diminishes 

 rapidly, though the contrary has been claimed in some instances of i)rofessional 

 fasting. In the experiments reported strength tests were made and in almost 

 every instance a notable falling off in strength was observed as the fast pro- 

 gressed. When food was again taken strength rapidly returned. 



The body excretions were the subject of special study. In the case of feces 

 it was found practically impossible to isolate, with any degree of accuracy, 

 material which could properly be designated " fasting feces." The urine was 

 excreted regularly. The volumes were in general normal though in many cases 

 where the subject consumed large volumes of water the amounts excreted were 

 likewise great. Considerable variation in the amount of total urinary nitrogen 

 was noted, but even in the longer experiments the daily output seldom fell 

 below 10.5 gm. Detailed data are also given regarding the variations in ex- 

 cretion of other urinary constituents. 



Marked variations in the amount of water vapor given off by the skin and 

 lungs were observed in experiments with different subjects and smaller varia- 

 tions in experiments with the same subject. On an average, the results show 

 that a fasting man gives off in this way not far from GOO to SOO gm. of water 

 per day. 



As the fasting period progressed a I'ather persistent decrease in the carbon 

 dioxid output was noted. In the 2-day fasting experiments wide variations 

 in the carbon dioxid output were observed with different subjects, though con- 

 sidering the period as a whole the agreement was reasonably uniform. Much 

 wider differences were noted between the oxygen intake on the different days 

 than was the case with the carbon dioxid output. 



