EXTEEME CLIMATES. 131 



antagonism to another wMch is frequently repeated and sup- 

 ported by numerous examples, namely, this : That animal life, 

 and more particularly the culture of the human race, can only 

 attain their highest development in cold climates, although as 

 a rule, not without exceptions, these manifest greater varia- 

 tions between the two extremes of temperature than tropical 

 or subtropical regions. The high degree of culture that obtains 

 among European nations is only attainable, so it is said, in the 

 region of the north temperate zone. No contradictory evi- 

 dence, it is true, is forthcoming. It might indeed be asked why 

 humanity has not attained to so high a degree of culture, nor 

 the animal world even reached such perfect development, in 

 those parts of the southern hemisphere which have a cold or 

 excessive climate, as they have done in Europe. But quite apart 

 from this objection, which is certainly open to discussion, the 

 opportunity afforded by favourable circumstances to some parti- 

 cular species of developing every individual to an average degree 

 of perfection and fitness on the one hand, and the value which 

 greater contrasts in temperature— that is to say, actually un- 

 favourable conditions of existence — may have in the modification 

 and progressive development of a species still capable of such 

 modification, are by no means identical. For it is self-evident 

 that the necessity for enduring abrupt alternations of heat and 

 cold can only be met by greater powers of resistance in in- 

 dividuals and by enlarged powers of adaptation; hence, in 

 extreme climates, the selection which will necessarily be effected 

 by the violent contrasts of temperature, must,, by eliminating 

 the weaker individuals, improve the race ; while in equable 

 climates, where this mode of selection is absent, the weaker in- 

 dividuals (weaker only in this one point) have as good a pro- 

 spect as the stronger ones of a long life and of transmitting their 

 characters. The two propositions, indeed, do not contradict 

 each other, but on the contrary complete each other. A species 

 whose individuals are at an end of their capability for under- 

 goiDg modification will succeed best in an equable climate, since 

 there every individual, without exception, will find an equally 

 favourable opportunity for reproduction — supposing of course 

 that no other selective agency is at work. But so long as a 



