I9I3] G. 0. Higley 397 



given for each subject where the necessary data were at band. In 

 each case the morning, midday and evening ciirves are represented, 

 respectively, by solid, long-dash and short-dash lines. 



Analysis of the results. Comparison of the data for haro- 

 metric pressure and carhon dioxide excretion. Before proceeding 

 to a rigorous mathematical investigation of the relationship between 

 barometric change and carbon dioxide excretion, it seemed desirable 

 to make a comparison of these two variables at a number of the 

 dates on which especially marked barometric fluctuations took place, 

 since in such cases the effect would be more pronounced and less 

 likely to be masked by other varying conditions, such as amount 

 and character of the preceding meal, character of muscular exercise, 

 etc. To f acilitate such a comparison Table 2 was prepared ; it 

 indicates experiment number; dates between which the comparison 

 is made ; barometric height, rise or fall ; subject ; carbon dioxide for 

 the two days between which comparison is made; rise or fall of 

 excretion; and relation between barometric change and carbon 

 dioxide excretion, whether direct or inverse. Taking first the 

 morning values, it was found that the barometer rose between 7 



A. M., December 23, and 7 A. M., December 24, from 739 to 746, 

 or 7 mm. During the same period the excretion of carbon dioxide 

 of the three subjects changed as follows : That of A from 406 to 

 438 mg. per minute, an increase of 32 mg.; that of B from 381 to 

 489, an increase of 108 mg., and that of C from 406 to 419, an in- 

 crease of 13 mg. per minute. Thus with rising barometer there 

 was an increase in the rate of excretion of carbon dioxide in the 

 case of each subject. A similar result is obtained in four other 

 morning experiments (two subjects). In three morning experi- 

 ments there are two direct results each. One experiment shows two 

 indirect results, i. e., there is a change in carbon dioxide excretion 

 which is opposite in sign to that in the barometer. 



Summing up the results of the morning experiments we have 

 the following : Eleven experiments were carried out on A, seven on 



B, and eleven on C. The degree of correspondence of barometric 

 change with carbon dioxide excretion was : 



A, 7 cases out of 11, or 63.6 per cent. 



B, 6 cases out of 7, or 85.7 per cent. 



C, 6 cases out of 11, or 55.5 per cent. 



