20 INFLUENCE OF FOOD PRESERVATIVES ON HEALTH. 



DETERMINATION OF TEMPERATURE AND PULSE. 



The temperature of the blood was taken sub lingua before and after 

 dinner each day. This method is probably the least accurate of all in 

 common use. it is, however, convenient and easy. Since the object 

 of the determination was to disclose any notable departures from the 

 normal, the method was considered fairly reliable. Standard clinical 

 thermometers of maximum registration were used for this purpose, 

 each subject being supplied with a separate thermometer. These ther- 

 mometers were all graduated through the courtesy of the Bureau of 

 Standards. 



The rate of pulse was also determined in connection with the deter- 

 mination of the temperature. This is, however, not a matter of so 

 very much importance because of the ease with which the rate of pulse 

 is varied by exercise and emotional influences. 



In general, an attempt was made to control as fully as possible all 

 the avenues which might lead to any .useful information concerning 

 changes, even of a minute character, in the functional activities of the 

 body during the period of observation. As has alread}' been inti- 

 mated, the final verification of any small changes of an organic nature, 

 especially of incipient lesions, which may take place is denied in exper- 

 iment upon human beings, but, in so far as possible, any intimations 

 of such changes which could have been secured by any of the ordinary 

 methods of study were noted. 



In data of this kind, namely the determination of the temperature, 

 rate of pulse, etc., where dependence is placed upon the subject him- 

 self, there are doubtless errors of observation which, are undetected. 

 Instructions, however, were given, and in so far as possible carried 

 out, to the effect that any variation of a marked character from a 

 normal state must be verified by a second observer. This rule applied, 

 not only to the variations in the body weight from day to day, but 

 also to the departures of the temperature from the normal, and to the 

 variations in the rate of pulsation of the heart. Thus, whenever one 

 individual in the class noted any marked variation from the normal he 

 called upon either one of the superintendents or one of his fellows to 

 verify the numbers which he had observed. By this precaution m&ny 

 errors which otherwise would have crept into the reports were avoided. 



BODY WEIGHTS. 



The weights of the body were ascertained by means of a platform 

 scale with agate bearings, and of a delicacy sufficient to register easily 

 differences cf weight of 10 grams when carrying a man of average 

 weight. There was of course some little annoyance occasioned in 

 taking the weights because it was necessary that they be taken naked. 

 It is not safe to assume that the weight of clothing remains constant, 



