284 KANSAS CITY REVIEW OF SCIENCE. 
degree, and he never thought of cutting the fast short, whatever may sometimes 
have been the opinion of his watchers. 
In order to’ understand what may be learned from this experiment we will, 
for the benefit of the non-professional reader, remind him of a few physiological 
principles. 
The chemical constituents of the human body have to be constantly renewed, 
and the waste has to be supplied by the food. Some of these constituents are 
wasted rapidly, others slowly, and in case of starvation the elements rapidly 
wasting away must be present in the body in sufficient quantity to keep the func- 
tions of life in operation. These rapidly wasting constituents may be divided into 
three classes, those in which carbon prevails, those in which nitrogen, and those 
in which phosphorus is the prevailing element. 
The carbonaceous compounds are wasted in keeping up the animal heat. 
This is accomplished by a slow combustion, that is, a combination of the carbon 
with the atmospheric oxygen, which is continually going on in the capillaries 
through the whole body, the oxygen being furnished by the blood, which absorbs 
it into the lungs, and which by thearteries is sent throagh the body. The product 
of this combustion, the carbonic acid, still absorbed in the blood, is by the veins 
sent to the lungs, where it is given off and escapes in the act of respiration. 
After having stripped Dr. Tanner, when he commenced his fast, for the double 
purpose of ascertaining his physical condition and leave no doubt that he had no 
food about him, it was seen that he had plenty of fat in and around his body to 
furnish carbon enough to last him more than forty days. 
The second element of rapid consumption is nitro,en; it proceeds from the 
waste of the muscular tissue, which is always going on, even during sleep, as the 
heart is a muscle continually contracting, and respiration is kept up by muscular 
action. The blood takes up this waste in the form of a compound, of which the 
chemical name is cyanate of ammonia, but which by physiologists is called urea. 
It is the function of the kidneys to secrete this from the blood, and numerous 
experiments have settled the nature and amount of this secretion, which in healthy 
persons consuming food, varies from 25 to 35 grammes every twenty-four hours. 
When Dr. Tanner began his fast it was secreted at the rate of 29 grammes, and 
as the nitrogen in any excess of nutrition is similarly changed and secreted, it 
was expected that a large reduction would be observed as soon as the fast began 
to have effect on the system. This expectation was realized, and the amount 
soon fell off to 23, 20, 17, 16 and finally 13 grammes, at which it remained sta- 
tionary, with slight oscillations beyond. ‘This amount of nitrogenous substance 
represents, therefore, the waste necessary to sustain the functions of life, and 
would at once be increased in case food was taken by the experimenter, at least 
nitrogenized food, such as beef extract or its equivalent, albumen, casein, milk, 
etc., the only substances which would be of benefit to him. Analytical chem- 
istry, therefore, acts here as a reliable detective, and to the credit of all concerned 
it must be said that never the least suspicious increase of urea was observed, it 
