'295 



Dr. A. Rattray on the Effects of [Feb. 16, 



The following experiments were made on myself (set. 39), on a voyage 

 from England to Bahia (lat. 11° S.), between June and September 1869. 

 During 24 days, from Plymouth to the thermal Equator, drink (tea or 

 coffee) being limited to 39 oz. daily, the urine gradually decreased from 

 39 to 30 oz., which merely proved that in semitropical, as in temperate 

 climates, free fluid is chiefly thrown off by the kidneys, and that this 

 diminishes as the heat increases. 



The following Table gives the results of the two subsequent days, 

 while passing through the equatorial doldrums or greatest heat, the drink 

 being suddenly increased to 88 oz. daily : — 



Table I. — To show the Urine excreted at the Equator. 



Locality. 



Ave- 

 rage 

 temp. 

 F. 



Date. 



9 A.M. 



Night urine. 



9 P.M. 



Day urine. 



Totals. 



Quan- 

 tity. 



Sp. gr. 



Quan- 

 tity. 



Sp. gr. 



Quan- 

 tity. 



Sp. gr. 



Equatorial doldrums 



1 80> 



July 14 



16 



15 



20i 



14 



36^ 



14* 



off the African Coast, 

















^lat. 11° N. . 



J 81 



July 15 





13 



21 



8 



37i 



10* 



Thus nearly 37 oz. were excreted by the kidneys, leaving 51 oz. to be 

 accounted for. Now the bile is scarcely if at all increased in the tropics, 

 so that the liver gives little aid. Dalton* gives ^ of the drink as the 

 average thrown off in this form and by the bowels in temperate latitudes. 



Taking this for the tropics also, allowing a little increase for bile, we have 

 4*4 oz. And reducing the water exhaled by the lungs in the temperate 

 zone (which, according to Dalton, is J of the drink or 22 oz.) by the same 

 ratio as the respired air, viz. 11 per cent, or 2*42 oz., we have 19*58 oz. as 

 that for the tropics. The sum of these two is 23*98 oz. Then the 

 51 oz. not thrown off by the kidneys 

 —23*98 oz. excreted by the lungs and bowels 



gives 27*02 oz. for the skin to exhale. 

 3o that the 88 oz. free fluid were got" rid of thus : — 



Urine 37 oz., skin 27*02 oz., lungs 19*58 oz., faeces 4*4 oz. 



Had the water in the solid ingesta been reckoned, a difficult matter on 

 shipboard, the experiment would have been more satisfactory. But this 

 gives a fair approximation, inasmuch as any excess from this source would 

 only have gone to increase the perspiration. 



The relative excretion of free fluid by the skin, kidneys, lungs, and bowels, 

 thus, differs in temperate and tropical latitudes, as they doubtless do in 

 arctic regions (Table II.). 



* Hooper, ' Physicians' Vade Mepum.' 



