1872.] 



changes of Climate on the Human Economy. 



7 



Thus in three adults it fell from an average of 17*3 per minute in 56° E. 

 to 16-1 in 82° E., and again rose to 17*5 in 53° E. To close observation 

 it was perceptibly slower and gentler*. However, as in temperate so in 

 warm regions, the frequency of the respiration varies with the activity 

 of the skin, purity of the blood, and need of the tissues for oxygen. 

 Thus my tropical respirations ranged from 11 to 15, average 12*74 per 

 minute ; the range for the temperate zone being 13| to 18, average 15*68. 



These three well-marked tropical phenomena, viz. diminished lung 

 vascularity, slower respiration, and gentler breathing, are closely related, 

 and together indicate reduced lung work, the reverse for the temperate 

 zone marking an increased function — thus proving that this varies with 

 temperature, as with age, sex, height, &c. Their aggregate results vary 

 with individuals, and perhaps races ; but the following is a fair average 

 of the reduction in the air respired and carbon excreted : — 



Table VI. 





Cubic inches of 

 air per respi- 

 ration from 

 Table 1Y. 



Number of re- 

 spirations per 

 minute, from 

 Table V. 



Cubic inches of 

 air respired 

 per minute. 





I3-25 



156 



195-69 f 



86 ' [ Temp, zone, temp. 54 F.... 



H'54 



1 6-5 



239*91 



Difference per minute in favour of a temperate climate ... 44*22 cubic inches, 

 hour ,, 2653*20 ,, 



„ day „ 63676*80 „ 



18*43 P er eent.= 3 6 ' 8 5 cubic feet J. 



Thus 239 cubic inches of air were respired per minute in the temperate 

 zone, against 195 cubic inches in the tropics, = a difference of 44 cubic 

 inches per minute, or 36*85 cubic feet per day, =18*43 per cent. 



Then, taking 10 oz. as the average amount of carbon thrown off by 

 the lungs in the temperate climate of England §, this reduction of 18*43 

 per cent, gives 8*157 oz. as the amount for the tropics. The pulmonary 

 excretion of watery vapour is doubtless correspondingly diminished. 



* The experiments further proved that, like the circulation (pulse), the respiration 

 increases towards infancy. Is the latter function, though actually less, relatively greater 

 then from the rapid renewal and deoxidation of tissue and food ? 



t Corrected for heat in accordance with Dalton and Gay Lussac's law, the difference 

 here being 27° F. 



j Former calculation (Proceedings, June 16, 1870) made this as 27*81 cubic inches less 

 of air per minute, =10*9 per cent. = minus 1*1028 oz. of carbon per day. But this 

 was based on limited data, in which the respiration was inaccurately fixed, and its 

 depth calculated not from direct observation, but from the increased spirometric 

 measurement of the lungs. 



§ Mean of three estimates by Lavoisier and Seguin, Davy, and Allen and Pepys. 



