THE RELATIONS OF METABOLISM TO FOOD-SUPPLY. 137 
brium of man could be maintained on a diet containing little nitro- 
gen but abundance of non-nitrogenous nutrients. Under these 
conditions the urinary nitrogen was reduced to 5.87 grams and 6.07 
grams per day respectively, and the total nitrogen excretion to 
7.45 grams and 8.10 grams, amounts much lower than have been 
observed for fasting men. Thus in the extensive investigations by 
Lehmann, Miiller, Munk, Senator, & Zuntz* of the metabolism 
of two fasting men, much higher figures than the above were ob- 
tained for the urinary nitrogen, and Munk (loc. cit., -p. 225) calls 
attention to the fact that in one case the urinary nitrogen on the 
second day succeeding the fasting period was materially less than 
on the last day of the fasting, viz., 8.26 grams as compared with 
9.88 grams. 
In a subsequent series of experiments upon dogs, Munk + showed 
that by very liberal feeding with food poor in proteids (rice with 
small amounts of meat) the nitrogen balance could be maintained 
for a considerable time at an amount very much lower than pre- 
vious observers had found for' the proteid metabolism of fasting 
dogs of similar weight. 
Length | Average Food per Day. Urinary 
of Exper- sere ‘ ; see 
iment, eight, . , 
4 eee 5 11.20 55 116 2.63 2.61 
é N fl oes 5 10.21 38 96 2.48 2.40 
Wathtoads \a0T. os: 4 9.88 | 53 | 108 | 2.66 | 2.67 
LV esses 4 8.25 47 100 2.60 2.62 
f Munk....... 14.4 3.65 
Fasting {eaick ee: 8.9 5.10 
Munk also cites in support of his conclusions Rubner’s results 
on a dog fed exclusively on carbohydrates. A reference to these 
results as tabulated on a subsequent page does in fact show in most 
cases a decrease in the proteid metabolism as compared with the 
fasting values, but how much of this is due to the normal decrease 
during the first few days of abstinence from proteid food it is dif- 
* Arch. path. Anat. u. Physiol., 131, Supp. 
ft Ibid., 182, 91. 
