THE PATH OF EVOLUTION 



birds, highly organized animals as they are. They 

 will sustain without freezing and uninjured for some 

 time a temperature but a few degrees above zero F. 

 The experiment has not been tried, so far as is known, 

 of testing the viability of the eggs of insects after 

 subjection to the low temperature of liquid air. The 

 farmers, however, in the Northwestern States of our 

 country know by painful and costly experience 

 that the eggs of caterpillars and other destructive 

 scourges of vegetation readily survive the almost arctic 

 weather of 30 to 50 degrees below zero F. 



In plants, as already has been described, spon- 

 taneous motion occurs in the algae and others of the 

 lower orders ; in the higher orders, with the excep- 

 tions noted, it is restricted to the circulation of the 

 plasma in the tubular cells of the plants. In the 

 lower orders the motion named presents every evi- 

 dence of being caused by sensation, consciousness and 

 volition ; all limited and vague, but clearly demon- 

 strable. The unnecessary substitution of the proper- 

 ties of the term chemie-taxia, proposed by Metchni- 

 koff, for apparently the volitional motion of the 

 Amoeba, Bacteria and Leucocytes, only introduces a 

 new, obscure and unknown cause of action of which 

 we know absolutely nothing, to explain that of which 

 we know something, though, it is true, not very 

 much. 



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