404 PRINCIPLES OF ANIMAL NUTRITION. 
fat and cane-sugar replaced each other in isoglycosic proportions, 
viz., 110 grams of fat and 168 of cane-sugar. In this case the 
amount of water consumed was uniform, viz., 400 grams. The gain 
or loss of live weight in five-day periods was: 
Period 1.......... DUG aT ac asalicecnnnetews + 385 grams 
Oo 3D nisin A Ge Gonties ater A ocea tans i —160 “ 
Davie ews ‘*, “ —Omitting first day.. — 20 “ 
A third experiment, in which amounts of sugar intermediate 
between the isoglycosic and isodynamic equivalents of the fat 
were fed, showed a gain on the former as compared with practi- 
cally no change on the fat. 
In a second series of experiments isoglycosic amounts of lard 
(110 grams) and cane-sugar (168 grams) were alternated every five 
or three days for eighty-five days, the basal ration consisting of 500 
grams of lean meat, and 400 grams of water being consumed per 
day. The estimated heat values of these rations were respectively 
1513 Cals. and 1145 Cals., but notwithstanding this difference they 
appeared to be equally efficient in maintaining the live weight. 
Whatever weight may attach to the deductions from the exper- 
iments upon work production, it is hardly necessary to urge that 
such a method of investigation as that employed in the above 
trials, while it may afford useful indications, is altogether too 
crude to disprove the theory of isodynamic values based upon 
Rubner’s more elaborate experiments. 
Respiration Experiments.—Kaufmann * has also reported respi- 
ration experiments in support of the views regarding the interme- 
diary metabolism promulgated by Chauveau. In his experiments 
the nitrogen excretion, respiratory exchange, and heat production 
of dogs variously fed were determined, in five-hour periods, by 
means of a radiation calorimeter in which the products of respira- 
tion were allowed to accumulate. (See pp. 69 and 248.) From the 
theoretical equations given in Chapter II he computes the figures 
given on the opposite page for the consumption of oxygen, produc- 
tion of carbon dioxide, and heat evolution in the various reactions. 
Besides determinations of the fasting metabolism the experi- 
ments included feeding exclusively with meat and also with rations 
rich in carbohydrates and in fat. For each diet, on the basis of the 
* Archives de Physiol., 1896, pp. 329, 342, and 757. 
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