150 TRINIDAD. 



of Venezuela (Codazzi) ; from 115 to 128 in Hindostan, near the 

 coast (Humboldt) ; in Paris, it was found, by Arago, to be 20 

 inches; in London, by Howard, 25; in Geneva, 30*50 inches 

 (Humboldt). During the first six months of the present year, 

 1855, the fall of rain was heavy, viz., 46 inches. 



By taking separately the first five months of the year allotted 

 to the dry season, and the last seven months which comprise the 

 wet, we have the following results : 2*52 inches per month during 

 the former season ; and 11'33 during the latter. We may there- 

 fore conclude that June, July, August, September, October, 

 November, and December are very humid, and the climate 

 generally damp : however, it is less so than these of Havanna, 

 Hindostan, and even the north coast of Venezuela. The greatest 

 quantity of rain which fell during any month, pending the period 

 of thirteen years, was 16-81 inches, viz., in August, 1851. 



I have already stated that the aforesaid physical agencies but 

 particularly light, heat, and humidity exercised the greatest 

 influence on animal as well as vegetable life ; I will now briefly 

 examine their influences on our own organs. 



Heat. Besides its well-known debilitating effect on the human 

 body, a high temperature seems to have a powerful action in 

 modifying certain functions. Under such temperature, the 

 cerebral activity is diminished, as well as the muscular power, 

 and the digestive organs are greatly enfeebled. Cutaneous 

 exhalation is much increased, and becomes apparent under the 

 form of perspiration ; in fact, it is brought to its summum in a 

 warm and damp atmosphere. Perspiration has, for effect, a 

 diminution of the quantity of heat produced in the human body 

 by natural processes nor does it act as a debilitating cause, to 

 the extent that is generally supposed ; for prostration of strength 

 is relieved by an abundant natural perspiration, and its increase, 

 when the air is not too damp, results in a counteraction of the 

 effects of a high temperature. I may adduce, as a proof of what 

 I advance, that individuals in robust health are generally those 

 who perspire the most. It is a principle in physiology, that the 

 greater the activity of an organ the more liable it becomes to 

 disease ; and, as a consequence, cutaneous affections must be 

 more frequent and serious in a warm than in a temperate climate. 

 Humidity. Warm air contains, even when comparatively dry, 

 a larger contingent of water than cold damp air. This aqueous 



