228 
PHYSIOLOGY: F. G. BENEDICT 
by serum or protein, a property essential for their use as internal anti- 
septics. The degree of bactericidal effect obtained depends not only 
upon the chemical nature of the compound but also upon the organism 
employed for the test. Comparative experiments with different bac- 
terial species and with different varieties of the same species have dem- 
onstrated in many instances remarkable specificity. One class of sub- 
stances, for example, killed B. typhosus in a dilution of 1 to 200 in two 
hours, whereas, in the same time it killed streptococcus in dilutions of 
1 to 50,000 or more. The toxicity of the substances varies naturally 
with the character of the group added to the hexamethylenetetramine 
molecule. 
A further study of the bactericidal properties of methyleneamino 
compounds in general, is now in progress. A detailed description of 
the chemical and bacteriological work will follow in the appropriate 
journals. 
CHEMICAL AND PHYSIOLOGICAL STUDIES OF A MAN 
FASTING THIRTY-ONE DAYS 
By Francis G. Benedict 
NUTRITION LABORATORY. CARNEGIE INSTITUTION OF WASHINGTON 
Presented to the Academy. March 9, 1915 
The important relationship between numerous diseases and the vari- 
ous stages of nutrition and the fact that many pathological cases border 
on complete or nearly complete inanition make a study of the physiology 
and chemistry of normal fasting of special importance to the physiologist 
and the clinician ahke. It is rarely practicable to make exhaustive 
and simultaneous observations in several physiological and chemical 
fields of study w^ith a subject undergoing a prolonged fast but the arriv- 
al in Boston in 1912 of a Maltese, A. Levanzin, who wished particu- 
larly to fast thirty-one days under strict scientific observation, presented 
such an opportunity. It was thus possible to supplement earlier data 
secured with men during relatively short periods of fasting (2 to 7 days) 
in the chemical laboratory of Wesleyan University. (Benedict, Car- 
negie Institution of Washington Publication No. 77, 1907.) 
In accordance with a previously arranged program and in cooperation 
not only with the entire scientific and computing staff of the Nutrition 
Laboratory but with several members of the faculty of the Harvard 
Medical School, an extensive study of this man was made. The experi- 
ment began April 14, 1912, with a preliminary period of three days 
with food, followed by thirty-one days of complete abstinence from 
