186 THE EVOLUTION OF LANGUAGE. 



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 

 inappreciable addition of two degrees changes the 

 country into a world of water. The glaciers, under 

 the new conditions, retreat into the mountains, the 

 vesture of ice drops into the sea, a garment of green- 

 ness clothes the land. So, in the animal world, a very 

 small rise beyond the animal maximum may open the 

 door for a revolution. With a brain of so many cubic 

 inches, and so many pounds of brain matter, we have 

 animal intelligence. Everything below that limit is 

 animal, and the number of inches or pounds below it 

 makes no difference. But pass to a brain not a few 

 but many pounds heavier, many cubic inches larger, 

 and very much more convoluted, and it is conceivable 

 that in passing from the lower to the higher figures 

 some such change might occur as that which differ- 

 entiates solid from liquid in the case of water. What 

 the chemist calls a " critical point " might thus be 

 passed, and from a condition associated with certain 

 properties — though in the brain we must speak of 

 accompaniments rather than properties — a condition 

 associated with certain other properties might be the 

 result. Thus, as Cope says, " some Rubicon has been 

 crossed, some flood-gate has been opened, which marks 



