ASA GRAY. 339 



anxious to do justice to the work of others. Many of the problems 

 upon which Darwin was at work were those in which Gray was most 

 interested ; and he was often able to aid Darwin by his observations, 

 and still more by his judicious and always acceptable criticisms. While 

 the naturalist at Down was absorbed in the study of climbing plants 

 and cross-fertilization, the greenhouses at Cambridge were also used as 

 nurseries for the growth of climbers, and the odd, irregularly flowered 

 plants which ought to be cross-fertilized. The writer recalls the time 

 when Dr. Gray hardly ever passed in or out of the Herbarium without 

 stroking — patting on the back by way of encouraging them it almost 

 seemed — the tendrils of the climbers on the walls and porch; and when, 

 on the announcement that a student had discovered another new case 

 of cross-fertilization in the Garden, he would rush out bareheaded and 

 breathless, like a schoolboy, to see the thing with his own critical eyes. 

 Darwin, in a letter dated July 20, 1856, confided to Gray that he 

 had " come to the heterodox conclusion that there are no such things as 

 independently created species, — that species are only strongly defined 

 varieties." In this letter he also says, " I assume that species arise 

 like our domestic varieties with much extinction." About a year after 

 this, September 5, 1857, Darwin wrote to Gray the now famous letter, 

 in which he propounded the law of the evolution of species by means of 

 natural selection ; and it was this letter, read at the Linnean Society, 

 July 1, 1858, on the occasion of the presentation of the joint paper of 

 Darwin and Wallace, "On the Tendency of Species to form Varieties; 

 and on the Perpetuation of Varieties and Species by Natural Means of 

 Selection," which fixed the date of the priority of the great discovery as 

 due to Darwin. What were Gray's own views on the subject of evolu- 

 tion previous to the publication of the " Origin of Species," in November, 

 1859, may perhaps be inferred from some remarks which he made on 

 January 11, 1859, when he presented his paper '"On the Botany of 

 Japan " to this Academy. He then stated that " the idea of the descent 

 of all similar or conspecific individuals from a common stock is so natu- 

 ral, and so inevitably suggested by common observation, that it must 

 needs be first tried upon the problem [of distribution], and if the trial be 

 satisfactory, its adoption would follow as a matter of course." In brief, 

 he was inclined to accept evolution, but wished more proof; and nearly 

 three years earlier, in a letter to Professor Dana, written December 13, 

 1856, he had well expressed his own attitude by sayiug, "I have as yet 

 no opinion whatever, and no very strong bias." He saw what was 

 coming, however, and in a later letter to Professor Dana, anticipating 

 the publication of the " Origin of Species," he says, " You may be sure 



