388 ADAPTIVE VARIATIONS. 



scientific are matters of common personal experience. 

 A hot day following suddenly on a long spell of cold 

 weather, or a cold one on a long spell of hot weather, 

 is felt much more keenly than days of considerably 

 higher or lower temperature which are led up to by the 

 gradual change of the seasons. Likewise also, weather 

 which appears very hot to one's self will be looked 

 upon as temperate by a native Indian, or even an 

 Anglo-Indian. Acclimatisation is often experienced 

 by those who indulge in excessive amounts of alcohol, 

 opium, or tobacco. For instance, De Quincey was at 

 one time in the habit of taking 8000 drops of laudanum 

 daily, this enormous quantity probably producing no 

 greater effect than a dose of 30 to 50 drops in an ordi- 

 nary man. Again, arsenic eaters are able to swallow 

 as much as A gm. without injury, or about four times 

 the ordinary lethal dose. 



These various observations made upon members of 

 all classes of the Animal and Vegetable Kingdoms will, 

 I believe, be held sufficient proof of the contention 

 that adaptability is present in all organisms, and is 

 therefore a fundamental property of protoplasm. 

 Whether every variation produced by change of en- 

 vironment is in the direction of adaptation to the 

 change, it is of course impossible to say; but probably 

 this is not the case, as, by reason of the close correla- 

 tion existing between many of the characters of an 

 organism, the change may produce a want of adapta- 

 tion in some of them, but an increased adaptation in 

 others. Supposing, however, it were possible to esti- 

 mate the change produced in every character in the 

 body, it seems to me almost certain that the sum total 



