96 STATE HORTICULTURAL SOCIETY. 



zones roamed the world around, in circumpolar regions. He supposed 

 that our plants thus had their origin somewhere about the pole. Aft ^r 

 awhile, the land became cold, ice began to form in a great sheet like that 

 which occupies the interior portion of Greenland and Alaska, and this 

 began to push down toward the south, and the glacial epoch was on. 



Now, this did not take place suddenly. It extended over several thou- 

 sand years, perhaps. These plants were driven to the south; driven down 

 upon all sides of the globe, and driven further in some places than others 

 — driven for down on our Appalachian chain, because the glacial ice went 

 far south here. The glacial ice probably also went for down on the 

 Japanese side, and these plants were driven down before the ice. After 

 a time came the return to a warmer climate, and the plants went back. 

 In the meantime, certain plants had lodged in the high mountains, and, 

 these mountains being cooler, there they remained. And that explains 

 the fact that on the top of Mt. Washington there are plants that are truly 

 inhabitants of Alaska and Labrador. The plants then returned toward 

 polar regions. After a while the circumpolar regions again became cold, 

 and a second glacial time came (in which we are perhaps living), and the 

 glaciers cap the northern ends of the earth. As I said, these plants were 

 forced down, and in similar climates they persisted. While they went 

 down, perhaps on all sides of the earth, they afterward died out in those 

 regions, unlike their original condition, and persisted in those regions 

 which, though on opposite sides of the globe, were similar in climate. 

 We know that Japan and America, in geological formation and in cli- 

 mate, are similar; and we have here the explanation of the curious fact 

 that the plants of eastern North America and Japan are alike. 



A Danish philosopher wrote, in 1834, that nearly all species were cre- 

 ated in one place, and at one time, but he supposed that some species 

 must have been created in two or three different places, because they 

 grow so far apart, and with barriers so great that one can not account for 

 their distribution. He cites a case of plants that grew in Iceland, the 

 Shetland islands, and the Pyrenees, and he supposed that these plants 

 must have originated two or three times — a theory of the multiple origin 

 of species. De Candolle also thought that certain species must have 

 originated two or three times, and cites the cases of a curious and frail 

 little plant that grows in America, and nowhere else in the world but the 

 Himalaya mountains. How could this plant grow in these two remote 

 places? Gray solved the mystery. It was driven down from the north 

 pole, and has persisted in the Himalaya mountains and here. We now 

 know of many similar instances. So Gray was really one of the first to 

 propose that all species of plants had one origin, and that all distribution 

 of plants and animals over the surface of the earth has been due to 

 change in the physical environment. 



I shall not attempt to bring to your minds any other reasons why the 

 doctrine of evolution should be accepted, save the record of the rock.^. 

 Palfpontology shows us the broken pages of the Book of Life (with more 

 missing links than anything else), but once in awhile it shows how forms 

 of life existed in past time. 



But the most important reason for belief in evolution is that we see it 

 every day, because we know the plant-breeder has the power to produce 

 one variety out of another, and that all the breeds of animals came from 



