
238 STORRS AGRICULTURAL EXPERIMENT STATION, 
to furnish protein, or bacon to furnish fat, or both. They 
were placed inside the chamber of a respiration calorimeter 
especially devised by Rubner for determining the respiratory 
products and the heat given off from the body. The deter- 
minations actually made were: the weight of the animal at the 
beginning and the end of the experiment, of food and water 
given, and of urine and feces: the percentages of fat in the 
food and of nitrogen in the feces and in the urine; the weights 
of carbon dioxide and water in respiratory products; and the 
calories of heat given off from the body. ‘The nitrogen was 
not determined in the food; the carbon was not determined in 
the food, feces, or urine and no nitrogen nor carbon balance 
was made. ‘The amounts of food and body materials oxidized 
were calculated from the nitrogen and carbon excreted. ‘The 
heat of combustion of these oxidized materials was calculated 
from the calculated amounts, and assumed heats of combustion. 
No determinations were made of heats of combustion of food 
or excretory products. 
For the balance of energy the income was calculated from 
the estimated amounts of material oxidized in the body, and 
the outgo was found in the determination of the heat given off 
from the body. Nine experiments were made, the periods 
ranging from one to twelve days, the total number of days 
being forty-five. The differences of estimated income and 
outgo of energy in the individual experiments ranged from 
about —5.2 to +3.2 per cent. of the total energy but.in most 
cases they were very small indeed, and the average for the 
whole forty-five days showed a difference of less than one-half 
of 1 per cent. It was assumed by the author that all of the 
energy given off from the bodies of the animals was in the 
form of heat. In his opinion these experiments furnish a 
proof that the nutrients of the food and the body materials 
consumed are the sole sources of heat in the animal body. 
There can hardly be a doubt that the opinion is justifiable 
and the experiments thus confirm the belief that the law of 
the conservation of energy applies in the living organism,* 

* Late experiments by Studenski with dogs have brought results entirely in the line 
of those of Rubner. Unfortunately, however, the description is published in Russian 



