NET AVAILABLE ENERGY—MAINTENANCE. 493 
Experiments in which Work was Done.—Somewhat earlier in 
point of time than the above experiments by Contejean were similar 
ones by Chauveau* in which the animal performed a uniform 
(unmeasured) amount of work per day. No attempt was made to 
determine the equivalence between food or body metabolism and 
the work performed, but the latter was simply used as a means of 
increasing the metabolism, while the relative value of the several 
nutrients in maintaining the store of energy in the body was esti- 
mated from the effect upon the live weight. The experiments, 
therefore, are not, properly speaking, work experiments, but belong 
in the same category as those of Contejean—that is, they aim to 
show in what proportions the nutrients may replace each other in 
a maintenance ration. 
In the first series the basal ration consisted of 400 grams of 
lean meat, to which was added in alternate six- or five-day periods 
either 51 grams of lard or an isodynamic quantity (121 grams) of 
cane-sugar. In one period 128.5 grams of dextrose was used in- 
stead of the cane-sugar. The animal (bitch) averaged about 16.8 
kgs. in weight. The gain or loss of weight i in each period (differ- 
ence between first and last weighings) was as follows: 
Period 1........... Par 25 iisanta @ Hav weeps ees 0 grams 
EAD ree ae tie Cane-sugar.............. +170 “ 
BES Pe Boge cy acces ee bards, .c oeac eee oie daw — 10 “ 
BO Ae coal weed Cane-sugar............00. +290 “ 
a Pee ere Warde sad-cca wk Peraeieal eia tats —265 “ 
EO! WIG i Sa sae Howes Dextrose F Oo 
De! reer rece ary ss Gsi2e8 Gateea gua gaoksens —295 “ 
In the first four periods the cane-sugar seems to have caused a 
gain in weight as compared with practical maintenance on the lard. 
During the last three periods the animal was in heat and a loss of 
weight upon the lard ration resulted, which was arrested on the 
dextrose ration. Water was given ad libitum for several hours after 
the work, but withdrawn at least twelve hours before weighing. 
No record is given of the amount of it consumed or of the water 
content of the materials fed. 
In another experiment, in which twice as much work was done, 
* Comptes rend., 125, 1070; 126, 795, 930, 1072. 
