306 WILEY— INFLUENCE OF PRESERVATIVES [Aprils, 



found among those who pass the examinations for the civil ser- 

 vice of the United States. In these examinations the very quah- 

 ties which were looked for in the young men in question must 

 be present or they could not receive the vouchers for character and 

 conduct which are necessary to entitle them to compete in the ex- 

 aminations. These young men were subjected to a careful physical 

 examination similar to that exercised upon those who apply for 

 policies in life insurance companies. This examination showed them 

 free from organic diseases and not to have suffered within a year, 

 usually not at all, from any serious disturbance of health. The sub- 

 jects were placed upon their honor, by a formal pledge, that they 

 would obey all the rules established for the experimental work 

 and abstain from any form of food and drink except that offered 

 in the regular course of the investigation. Those who used to- 

 bacco, tea and coffee were permitted to continue to do so in the 

 regular manner so as not to change the habits of their previous 

 daily life. They were also limited by their pledge to a regular 

 course of exercise which they undertook to follow without varia- 

 tion, and also regular hours of work and sleep. As a justification 

 of the faith and confidence reposed in these young men I think it is 

 sufficient to say that, although during the five years of the experi- 

 ments we have had about sixty young men under observation, onl\- 

 three have been found to have violated their pledges. 



The subjects so selected were first placed on a generous diet 

 of the kind and character to keep them in equilibrium; that is. to 

 maintain the weight of their body without notable changes. The 

 part of the experiment devoted to this purpose was known as the 

 " fore period." Each one was allowed to determine, within cer- 

 tain limits, the character of the diet from the foods oft"ered ; that is, 

 a relative amount of meat, bread, potatoes, butter, milk, coft"ee, tea, 

 etc., to suit his taste and to conform with his previous habit of 

 life. Only in those cases where an excess of some particular kind 

 of food seemed to be preferred was any restriction placed upon this 

 matter. This fore period, therefore, enabled us to determine the 

 magnitude of the ration which would preserve the body equilibrium 

 and presumably be in entire conformity with the normal digestive 

 functions. 



