On the Temperature of Man within the Tropics. 75 



gentle, coming under the designation of passive rather than active 

 exercise, has a heightening effect on the temperature, while the latter, 

 the passive kind, has rather a lowering tendency, especially carriage 

 exercise. 



5.. That heavy clothing, especially if tight and close, obstructing 

 the admission and circulation of air, tends to raise the temperature 

 unduly, especially under active exercise ; and that close, ill-venti- 

 lated rooms, especially when crowded, have in a marked manner the 

 same tendency. 



6. That when the body is in a healthy state, then on rest aftei 

 exercise or exposure to any other exciting cause, it rapidly recovers 

 its normal condition as to temperature. 



7. That when labouring under disease, however slight, the tempe- 

 rature is abnormally elevated; and that — judging from observations 

 made, but not recorded, in the tables — its undue degree is some 

 criterion of the intensity of the diseased action. 



8. That within the tropics there is comparatively little difference 

 of temperature between the surface of the body, especially the extre- 

 mities and the internal parts ; — and that there the skin is more active 

 in its function of transpiration and the kidneys are less active as 

 secreting organs ; with which it may be conjectured is connected a 

 rapid production and desquamation of cuticle, and the absence, in great 

 part, or entirely, of lithic acid in the urinary secretion. This latter 

 fact, however, may be explained in a different manner, on the supposi- 

 tion that the acid is not formed in the blood, or, if formed, in a greatly 

 diminished quantity. 



9. That the effect of wine, unless used in great moderation, is 

 commonly lowering, that is as to temperature, whilst it accelerates the 

 heart's action, followed after a while by an increase of temperature. 



10. That the tendency of sea-sickness is^ to check what may be 

 considered the natural fluctuation of the temperature, and when 

 severe, like disease, to elevate the temperature. 



11. That the tendency of a sea-voyage, apart from sea-sickness, 

 is to equalize the temperature without elevating it, a^i equalization 

 that is best witnessed in voyaging in a tropical sea, where the atmo- 

 spheric temperature is so little variable, 



12. That even at sea, with a change of atmosplieric temperature, 

 there is a tendency to change of temperature of the body, the ave- 

 rage increasing in proceeding towards the tropics, and diminishing 

 in receding from them. 



These conclusions obviously admit of application, and that vari- 

 ously in relation to health and disease. It would be unsuitable to 

 the occasion to dwell on this part of the subject ; I shall merely 

 remark, that it is a happy circumstance for man, and seems wisely 

 ordered, that fluctuation of temperature should bo connected with a 

 healthy state of the system, and probably conducive to it, in what- 

 ever manner produced, whether by change of climate, or atmo^ 



