THE EARTH THE ABODE OF LIFE 



the rays of the sun more effectively than a garment. 

 Lately Dr. Sambon has pointed out that the white 

 linen clothes which Europeans generally wear in the 

 tropics, though they look cool, are not sufficient screens 

 against the rays of light and heat, and has suggested 

 that white men's clothes, to be properly protective 

 against the sun, ought to be woven of threads of two 

 colours, so that the garments should be white outside 

 and black inside. Apply these principles to animals 

 in sea-water, who were distressingly affected by con- 

 ditions to which they had never been subjected. What 

 would happen? The weaker would probably be killed 

 by the change in the conditions, just as some fresh-water 

 fishes and animalculse would be killed now if plunged 

 into sea-water. The stronger would, however, become 

 acclimatised, and would in the course of successive 

 generations struggle to adapt their bodies to the new 

 conditions. 



Thus the living organisms in the earth's early sea 

 contrived to cut themselves off from being bathed with 

 the novel carbonaceous water. They cut themselves off 

 from it in the course of generations by closing them- 

 selves off from it with skin or membrane. Many of 

 them stirred up their cells to secrete lime and exude 

 it so as to form for themselves a more or less impervious i 

 covering or shell. Finally, as they grew to like the mineral 

 water less, they continually made fresh experiments to 

 avoid it, and the more enterprising and adventurous got 

 out of the ocean altogether, and migrated to the air 

 or the land, perhaps by way of the shore sands and 



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