BORIC ACID AND BORAX. 29 



investigation the members of the table were made temporarily ill by 

 the quantities of the preservative administered, it is nevertheless an 

 interesting fact to note that at the end of the year, after the final " after 

 period" had been passed, they appeared to be, and declared themselves 

 to be, in better physical condition than when they entered upon the 

 experimental work seven months before. 



This fact, as has already been stated, must not be neglected, since it 

 is evident that the tendency toward a good physical state and good 

 health produced by the regular habits of life might counteract the 

 unfavorable tendency of any exhibited preservative; so that at the end 

 of the observation, if the results were judged only by the condition of 

 the subject at that time, they might be pronounced negative, or even 

 helpful, whereas in point of fact the preservative might have pro- 

 duced injurious effects. Self-restraint, temperance, regularity of exer- 

 cise, regularity in hours of sleep and hours of work are believed to 

 have favorable effects, and these were manifested in a marked degree 

 throughout the whole of the experimental work. 



MENTAL ATTITUDE. 



That the personal attitude of the individual experimented upon influ- 

 ences, to a certain degree, the progress of digestion is undoubtedly 

 true. Every physician and physiologist is familiar with the marked 

 effect which mental states produce upon the bodily functions. These 

 effects may be either favorable or unfavorable. Cheerful surround- 

 ings, good company, and, in general, an agreeable environment, tend to 

 promote the favorable progress of digestion. A reversal of the con- 

 ditions of environment to the disagreeable, combined with mental 

 depression, bad news, and other unfavorable conditions, have exactly 

 the opposite effect. 



The question therefore arose in connection with the experimental 

 work as to the advisability and possibility of preventing the mental 

 attitude from producing any effect. A careful consideration of all the 

 conditions of the problem made it clear that it would be impossible to 

 conduct the experiments in any way which would exclude from the 

 knowledge of the participant the fact that preservatives were added 

 to the food. It was fully understood that he was employed for this 

 purpose, and the very moment that the observation began upon his 

 daily life, by weighing the food and collecting the excreta, he would 

 be aware of the fact that he was under observation and was probably 

 partaking of preservatives. 



The question also arose whether or not the preservatives should be 

 given in capsules op, nly or whether they should be concealed in the 

 food itself. Both of these methods received a thorough experi- 

 mental trial. When the preservative was mixed with the food in 

 such a way as to conceal its physical appearance, a certain dislike 



