96 FOOD INGESTION AND ENERGY TRANSFORMATIONS. 



temperature. Many inconsistencies that appear at first sight in the 

 results of these experiments, as, for instance, those with L. E. E. 

 (table 32) , may properly be ascribed to erroneous measurements of the 

 body-temperature or to the lack of such measurements. 



At about the time these experiments were made special attention 

 was devoted to the measurement of heat production and the descrip- 

 tion of a special apparatus for measuring the body-temperature deep 

 in the rectum was published. 1 It has been impracticable in all sub- 

 sequent researches to take advantage of this method of measurement, 

 and yet experience in this laboratory, as well as elsewhere, has shown 

 that heat elimination as measured by the respiration calorimeter can 

 have but little significance without a definite knowledge of the very 

 considerable change in the body-temperature that may accompany a 

 normal or physiological experiment and is quite likely to accompany 

 observations on pathological cases. 



If we make a general study of the metabolism data obtained in these 

 Boston experiments, the results may be summed up as follows: As a 

 rule, the average values for the gaseous metabolism for each subject 

 show uniformity, although at times there is more or less variation in the 

 individual values. Owing, probably, to the fact that the body-tem- 

 perature measurements were lacking or defective, there is frequently 

 considerable variation in the heat output, although even here the values 

 do not lack uniformity in some cases. With the two subjects who were 

 studied in both the chair calorimeter and the bed calorimeter, lower 

 values were invariably found with the bed calorimeter, this being due 

 to the greater degree of muscular repose. 



It should be noted that the criterion for uniformity is a plus or minus 

 variation of 5 per cent that is, if the values for the carbon dioxide or 

 the oxygen are within 1 gram of each other on the 20 to 25 gram basis, 

 they are considered reasonably uniform. Hence we must admit at the 

 outset the possibility of variations in the individual periods of at least 

 plus or minus 5 per cent. This is important to note in any subsequent 

 use of these values in determining the influence of the ingestion of food, 

 for frequently the effect of the ingestion of food may be not much out- 

 side this limit. Accordingly this basis of experimentation for food 

 experiments, while favorable when a large effect of digestion is to be 

 expected, is still of doubtful value when the subtler effects are studied, 

 as they may be entirely lost sight of. 



We see no reason, however, why the results of these experiments 

 should not, with intelligent appreciation of their defects, still be used 

 for comparison with the results of experiments made under identically 

 the same experimental conditions after the ingestion of food. One 

 major criticism of so using these values may be made, in that while 



Benedict and Slack, Carnegie Inst. Wash. Pub. No. 155, 1911. 



