MISCELLANEOUS METHODS AND APPARATUS. 75 



BODY-WEIGHT MEASUREMENTS. 



Since it was impossible to establish the complete measure of the 

 income and outgo of each of these men in a respiration calorimeter of 

 sufficient size to enable them to carry on physical activity comparable 

 to their ordinary collegiate activities, it became necessary for us to rely 

 in the last analysis upon the changes in body-weight as an index of the 

 nutritive condition. For short periods nothing could be more erro- 

 neous than to follow this rule. The hterature is full of illustrations of 

 undue emphasis being placed on either considerable changes in body- 

 weight or on slight changes incidental to alterations in diet. As 

 is well known, since the body contains so large a proportion of water, 

 a change of 1 or 2 kg. in body-weight may be in large part due to 

 changes in water content and not to a change in the amount of 

 organized body-tissue. Still in this research body-weights determined 

 over a long period of time could fairly be taken as indices of the con- 

 dition of nutrition. Since they were so important a factor in noting 

 the effect of the reduced diet, it was increasingly necessary to take 

 unusual precautions as to accuracy, regularity of record, and suitability 

 of technique. 



The body-weights were all taken in the early morning, with the nude 

 subject in the post-absorptive condition and after the bladder had been 

 emptied. This did not make allowance for undischarged fecal matter, 

 but with the average individual these variations would not be very 

 great, especially over a long period. One of our subjects, however, 

 Pec, defecated regularly but once every 5 days; it is important to note 

 that his body-weights may be affected by the presence or absence of a 

 large amount of fecal matter in the colon. The subjects were weighed 

 either upon a platform balance of unusual sensitivity (the so-called 

 ''silk scale" manufactured by the Howe Scale Company, with a 

 capacity of 150 kg. and a sensitivity of 10 grams) or, as was done in the 

 latter part of the test, upon an accurate and carefully calibrated spring 

 platform balance. The latter balance, which is manufactured by John 

 Chatillon and Sons, is designed especially for recording body-weights, and 

 has a large dial which can easily be read to 0.25 kg. ; a large number of 

 body-weights were obtained with this balance. The records of the 

 body-weight were checked by some member of the Laboratory staff. 

 In no instance was an individual record made by the subject or an 

 unchecked figure recorded. 



BODY-SURFACE MEASUREMENTS. 



Measurements of body-surface were made in all cases. It is greatly 

 to the credit of D. and E. F. Du Bois that their methods for body- 

 surface measurements have been so carefully outlined that relatively 

 little training is necessary to secure accurate measurements of the 



