532 THE WONDER OF LIFE 



part of the living cells to the noxious stimulus of the micro- 

 organism or its soluble poison, a response of a protective 

 nature rather than of any other kind. Hence the indis- 

 criminate lowering of the temperature by drugs (anti- 

 pyretics) is not now nearly so common as it used to be. It 

 is recognized as possible that the increase of heat (fever) 

 may be evidence of sufficient vitahty on the part of the 

 living protoplasm to withstand the assaults of the infective 

 agents, the increased heat being the biophysical response 

 to the micro-organic insults '. 



It is a familiar fact that hving at a high altitude puts a 

 strain on the heart, which has more work to do. Some 

 people cannot hve above a certain level. In this con- 

 nection it is interesting to refer to a careful comparison 

 made by Strohl of ptarmigan from high altitudes and willow- 

 grouse from the plains. He found that in the ptarmigan, 

 even in the young bird, the right ventricle of the heart is 

 very distinctly stronger than in the willow-grouse. This 

 seems clearly to indicate a specific adaptation of the heart 

 to the difference of habitat. 



One of the subtlest of adaptations is immunity to the 

 poison of some enemy. Thus in some parts of Europe there 

 is an intrepid little Rodent, the lerot {Eliomys nitela), a 

 relative of the dormouse, which has pluck enough to fight 

 with vipers, and G. Billard has shown that it is immune 

 to their venom. A similar immunity to snake poison is 

 possessed by the mongoose, the pig, and the hedgehog. 

 And as to the last. Dr. Strubell has shown that it is 

 relatively immune to the toxins of diphtheria and tetanus. 

 It is likely enough that the hedgehog has a special anti- 

 toxin which counteracts the toxin of snakes, but it is 

 difficult to understand what is meant by its indifference to 



