THE EVOLUTION OF LANGUAGE 237 



a degree as to make the preceding argument a 

 petitio principii. Obviously the discovery of Lan- 

 guage could not in the first instance have been 

 responsible for the Evolution of Mind since Man 

 must already have had Mind enough to discover it. 

 But this does not necessarily imply any very high 

 grade of intellect — very high, that is to say, as 

 compared with other contemporary animals — for it 

 is possible that a comparatively slight rise in intel- 

 ligence might have led to the initial step from which 

 all the others might follow in rapid succession. 

 An illustration, suggested by a remark of Cope's, 

 may help to make plain how a very slight cause 

 may initiate changes of an almost radical order 

 and on the most gigantic scale. 



In part of the Arctic regions at this moment 

 there is no such thing as liquid. Matter is only 

 known there in the solid form. The temperature 

 may be thirty-one degrees below zero, or thirty-one 

 degrees above zero without making the slightest 

 difference ; there can be nothing there but ice, 

 glacier, and those crystals of ice which we call 

 snow. But suppose the temperature rose two 

 degrees, the difference would be indescribable. 

 While no change for sixty degrees below that 

 point made the least difference, the almost inap- 

 preciable addition pf two degrees changes the 



