448 



Tir 



EDICINE AND MEDICAL STATiSTICB. [Sect, XIV. 



the manner in whlcli the different forms of morbid action 



( 



o 



staLlished) progress^ culminate, and decline, 



that are so clearly demonstrable as could be wished. 



As a humid state of the atmosphere, particularly 

 within the tropics, seems to exercise a considerable in- 



fluence over the health of Europeans, hygrometrical 

 observations are not less essential than thermometrical, to 

 a full investigation into the causes and nature of anv of 

 those diseases usually denominated climatoriah Various 

 instniments have been used for these purposes ; but those 

 which denote with ordinary accuracy the state of the 

 atmosphere, and are the least liable to get out of repair, 

 are the best- The appearance of surrounding object 



and our ordinary sensations may be even trusted where 

 there are no better means at hand. It will naturally 



occur to the observer to guard against confounding the 



moisture arising from any local cause, such as damp 



» 



decks, or the halitus from the breath of a large body of 

 men confined in a small sparse, with the natural moisture 



J 



of tlie external air. Should the disparity, however, be- 

 tween the latter and the air of the deck on which the 



men generally congregate and sleep 



) 



be exeat, it will be 



incumbent on him when he uses an instrument to note 

 the differeiice. From these data, viewed in comiexion with 

 the results of the thermometer, the nc_assity of a more 

 fi-ee ventilation in all vessels of war destined to remain 



r^ 



* = ■* « 



lor 



years witiixn the humid regions of the tropics may thus 

 be made apparent. 



To a dry air wc are accustomed to attribute a bracing 

 effect, to a moist air a relaxing ; and there seems to be 



little reason to doubt the general truth of the postulatu 



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