HOME LIFE 425 



taining fossil remains proving any change of fauna and flora 

 such as Darwin had advocated. He then continues — 



" I know of no evidence of this kind, and I don't think 

 that Darwin has given any time or thought to Croll's eccen- 

 tricity theory, or to my chapters upon it, and I wish much 

 that he could see your review 1 before he came out with 

 this new edition (the fifth) of 'The Origin'; for I am 

 afraid that he will make too much of the supposed corrobora- 

 tion afforded by the imaginary warmth of the southern 

 hemisphere, and of the equally hypothetical expulsion of 

 tropical forms from the equatorial zone north of the line." 



In the sixth edition of the " The Origin," published three 

 years later, Darwin still held to his views of the extreme 

 severity of the glacial epoch influencing even the equatorial 

 zone, and explaining the transmission of so many northern 

 types of plants and insects to the southern hemisphere, as 

 shown by the following passage : — " From the foregoing facts, 

 namely the presence of temperate forms on the highlands 

 across the whole of equatorial Africa, and along the penin- 

 sula of India, to Ceylon and the Malay Archipelago, and in 

 a less marked manner across the wide expanse of tropical 

 South America, it appears almost certain that at some former 

 period, no doubt during the most severe part of a glacial 

 period, the lowlands of these continents were everywhere 

 tenanted under the equator by a considerable number of tem- 

 perate forms. At this period the equatorial climate at the level 

 of the sea was probably about the same with that now experi- 

 enced at the height of from five to six thousand feet under 

 the same latitude, or perhaps even rather cooler " (p. 338). 



In my " Island Life " I have discussed at some length all 

 these facts, and many others which Darwin did not take 

 into consideration, and have explained them on the theory 

 that the glacial epoch had no effect whatever in lowering 

 the temperature of equatorial plains, while it might easily 

 lower the snow-line on even equatorial mountains. Those 



1 My Quarterly Review article on " Geological Climates and the 

 Origin of Species," a proof of which Sir Charles had seen. 



