METABOLISM IN FASTING 95 



amount of heat produced in each experiment by the destruction of proteid, 

 fats and carbohydrates. These results are given in other columns. 1 



The greatest difference between A and B is 4.1 per cent, the least difference 

 is 0.1 per cent. In the rest series the mean difference is 0.1 per cent, in the 

 work series 0.3 per cent. 



It is, therefore, conclusively demonstrated by Kubner's and by Atwater's 

 experiments that the foodstuffs generate the same quantity of heat when 

 burned within the body as when burned outside the body. From a com- 

 parison of column E with D, in the foregoing table, it follows also that the 

 calorific estimation of metabolism by means of the standard heat values of the 

 organic foodstuffs yields very satisfactory results in the light of the heat 

 production as actually measured. 



3. METABOLISM IN FASTING 



Quantitatively considered, metabolism takes the simplest form in the fast- 

 ing condition, when the body is living exclusively at the expense of its own 

 combustible materials. Hence it will be best to begin the discussion of the 

 processes of metabolism with a presentation of that which takes place in 

 fasting. 



A. THE GENERAL CONDITION IN FASTING 



It is commonly supposed that fasting is a very painful state. But this 

 is not the case. Observations on starving animals as well as fasting experi- 

 ments recently carried out on men show that no real pain is felt. 



During the first day of fasting, especially at the usual meal times, there is 

 a feeling of hunger, but it soon disappears; and it may even happen that when 

 the individual is again permitted to eat, he has no real desire for food. Neither 

 animals nor men have any great need for water during the fasting condition. 

 Fasting dogs often do not drink when water is offered them, and fasting men 

 give out much more water than they take in. 



What is especially characteristic of the fasting condition is the progressive 

 loss of strength. But even this is not always pronounced, as will be seen from 

 the case of Succi observed by Luciani. Succi fasted for thirty days, and on the 

 twelfth day he took a horseback ride lasting one hour and forty minutes; the 

 same evening he walked around the room a great deal, ran an endurance race 

 with three young students which lasted for eight minutes, and then went through 

 a fencing exercise. On this day he took 19,900 steps. On the twenty-third day 

 of his fast, he visited the theater in the evening, and there engaged in two bouts 

 with swords, in which he showed endurance, strength and agility. On this day 

 he took 7,000 steps. 



The pulse frequency decreases during rest in the fasting state; but with 

 very slight exercise it rises much higher than normal. The body-temperature 

 (rectum) remains normal or falls only 0.1-0.3 C., until within the last few 

 days (third to ninth) before death by starvation, when it falls rapidly and 



1 Since the Calorie as used by Atwater is based upon water at a temperature of 20 C., 

 and is therefore about 1 per cent lower than that usually employed (0 C.), we have used 

 the following figures in this calculation: 1 g. proteid - 4.2 Cal., 1 g. fat = 9.4, 1 g. carbo- 

 hydrate = 4.15. 



