INTRODUCTORY ESSAY. 27 



and the Malay peninsula and islands, produce an abundance 

 of well-marked species of plants, whilst the dry, hot/ lowei 

 hills of Central India, with contrasted seasons, produce com 



ditliculties 



systeniatist 



peninsula, which have marked seasons, are com 



in 



and South America, also having 



summer 



winter 



Such discrepancies prove how 



element 



naturalist should be in generalizing upon its effects. They 



of 



paramount in determinin 



forms. We learn from them also that the primd 



f 



put aside j and they suggest the propriety of instituting ob- 



m 



may be called, which develops the relations between the num- 

 ber of orders, genera, and species, contained in an area, and its 

 climate and other physical characters. 



And now that we are on the subject of variation, it ap- 



the 



of studying its phenomena 



W 



will find it the most profitable department of 



ystematic 



gations will 



le variations of species, consistently with 



I certain definable limits. We shall offe 



marks on this point under two heads : — variation 



possessm 



same 



between different indivi- 



duals of the same species. 



1. 



-4 



From 



uxui 



cue lUAUiiaiiuc ui cue vi/gvt*"^" "• 



tanist is so often surrounded, and the rapidity of its develop- 



meut 



that ob- 



ervers in colder climates do not possess. In general terms, 



