46 HABITUDES 



in which it is an ordinary endemic, is not an exception to 

 this law, for Baron Humboldt says that, at Vera Cruz, 

 where "May and June are hotter than September and Oc- 

 tober, the latter months greatly exceed the former in the 

 number and vigor of the fevers."* 



If mere vegetable decomposition were the cause of such 

 fevers, we should find them most active in May and 

 June, when, after the previous autumnal death, and the 

 disintegrating effects of winter frosts, or soaking rains, the 

 warmth and moisture of spring and early summer rapidly 

 decompose the softened textures, to feed the tender spon- 

 gioles of the swelling vegetation. The great chemists, heat, 

 light, and moisture, are then most active; and the dead 

 relics of the former year, prepared by time, frost and rain, 

 are ready for the process of decomposition, as the electri- 

 cal and vital agencies of the countless and thread-like 

 radices open up their intendered store-houses of nutrition. 

 Although, therefore, almost every one has supposed that 

 the autumn is the season of the greatest decomposition, 

 that process is really conducted in the spring and early 

 summer with a tenfold energy, as may be easily recog- 

 nized by the extraordinary smell of the earth Sfter a shower 

 at this season. 



Malarious diseases, therefore, are not probably the effect 

 of ordinary vegetable decomposition; for they occur most 

 when that is not at, or near to, its maximum. 



Everywhere they abound, when the general vegetation 

 has just passed through its great orgasm. But there 



* The regular return and continuance of this fever in the months of 

 July, August and September, every year, more or less since its iirst appear- 

 ance in these Islands (Jas. Clark, Dominica.) 



Yellow Fever is most active in September, when the temperature has 

 fallen much below that of July and August. (Wm. Currie.) 



