24 PHYSIOLOGY CHAP. 



the quantity of carbon we can find, after deducting the carbon 

 of the protein consumed, the approximate quantity of fat, etc., 

 consumed. 



From the concordant results of the investigations so far made 

 upon the metabolism during fasting, both of man and animals, we 

 find that the protein consumption steadily decreases at first 

 rapidly, afterwards more slowly. On the other hand, the con- 

 sumption of fat, if the man or animal has a good provision before 

 the fast begins, does not vary much from the beginning to the 

 end of the fast. 



During Succi's thirty days' fast I found that the daily average 

 consumption of protein was very small; this explains Succi's 

 extraordinary power of fasting for long periods. On the first day 

 of the fast the urine contained 13'8 grms. of nitrogen = 29'6 grms. 

 of urea ; on the tenth day the quantity fell to 6'7 grms. = 1447 

 grms. of urea; on the twenty-ninth day it amounted to only 4 

 grms. = 8 '74 grms. of urea. 



If we compare these data with those obtained by Munk 

 during Cetti's ten days' fast, we find that the average for the 

 nitrogenous consumption was very much higher : on the first day 

 28 grms. of urea, on the tenth day 20 grms. If the proportion of 

 this consumption to the body -weights of the fasting men be 

 calculated, we find that on the first day Succi discharged 0'47 

 grin, of urea per kgrm. and Cetti 0'51 grm. ; while on the tenth 

 day Succi discharged 0'25 per kgrm. and Cetti - 39 grm. These 

 differences are due in great measure to the fact that Succi was 

 a mature . man well provided with fat, while Cetti was a thin 

 youth and consequently could not economise the consumption of 

 nitrogenous substances by burning his fat. 



It is worthy of note that during the first three or four days of 

 fasting, the nitrogen in the urine does not gradually decrease as is 

 the case in the following days of inanition, but, on the contrary, 

 increases somewhat. Thus in the five days' fast of a young 

 student, Tigerstedt found the following amounts of nitrogen in 

 the urine: first day, 1217 grms.; second day, 12-85; third day, 

 13-61 ; fourth day, 13*69 ; fifth day, 11-47. This result is easily 

 explained by the assumption that during the first days of fasting 

 the glycogen stored up in the body is consumed more readily 

 than the fat, thus effecting a great saving in the consumption 

 of the protein. In proportion as the store of glycogen decreases, 

 the quantity of nitrogen in the urine must increase, and the 

 gradual diminution of nitrogen becomes noticeable only when all 

 the glycogen has been consumed. Whilst an ample provision of 

 fat in the person who is fasting economises the consumption of 

 protein during the whole course of inanition, the store of glycogen 

 only does so during the first few days. 



The sulphur discharged during the fast in the form of alkaline 



