692 INFLUENCE OF CLIMATE. 



versity of organized bodies must be immediately 

 connected with the agency of external tempera- 

 ture. 



Perhaps there is not a greater contrast between 

 the plants and animals of different planets, than 

 between those of the tropical, middle, and polar 

 latitudes of the earth. We have already seen, 

 that the number of volcanoes, the elevation of 

 mountains and plains, the amount of evaporation 

 and rain, the magnitude of rivers, and the growth 

 of vegetation, are in proportion to the heating 

 power of the sun. Nor can there be a rational 

 doubt, that if the earth were only a few millions 

 of miles more or less distant from the sun, or that 

 if the inclination of its axis were only a few de- 

 grees more or less than at present, all its chemi- 

 cal, geological, and physiological operations would 

 exhibit corresponding variations.* 



* As the law of gravity was first demonstrated by observing 

 the revolutions of planets and their satellites, so will the great 

 laws of physiology and pathology be discovered by means of ac- 

 curate observations, extended over all parts of the earth, in regard 

 to the influence of climate, geographical position, modes of living, 

 civilization, forms of government, &c. on the physical organization 

 and character, intellectual and moral, of the human race. It would 

 be a great acquisition to our knowledge of the natural history of 

 man, if all governments were to require annual returns of the 

 marriages, births, stature, circumference of the chest, dimensions 

 of the head, (from infancy to the completion of growth,) increase 

 of population, diseases and mortality, of all their inhabitants. 

 May we not hope that philosophers will use their best exertions 

 to bring about so desirable an object. 



