8 Canadian Record of Science. 



Some very interesting experiments are at present 

 being carried out on butterflies in Cambridge. Some 

 European species of butterflies are well known to be 

 represented by two varieties — a mountain variety found 

 in the upper meadows of tlie Alps, and a valley variety. 

 The mountain variety is a dusky form. ISTow it occurred 

 to Mr. Bateson, a distinguished naturalist in Cambridge, 

 that if one started below in the valley and worked one's 

 way upward, one of two things must happen ; either one 

 would find a slow gradation of one variety into the other, 

 or one would arrive at a point where the two varieties are 

 found flying together. Mr. Bateson found, as a matter of 

 fact, that it was the latter alternative which was really 

 the case. He collected a quantity of each variety and 

 crossed them. The result is very interesting; the two 

 varieties are perfectly fertile amongst themselves, but the 

 offspring are not intermediate in character between the 

 two parents ; they either " take after " the father or the 

 mother. Now, I feel sure that there are many cases 

 known to the entomologists of Montreal where similar 

 experiments could be made, and only in such ways shall 

 we gradually arrive at an idea how one species may have 

 given rise to two. In passing, it may not be inopportune 

 to remark that there is a great deal of misconception 

 in the way in which many people represent the modus 

 o^Jcrandi of evolution to their minds. They speak as 

 if they believed that evolutionists thought that one 

 species living in one place, of its own internal motion, 

 broke up into two or three species, and hosts of imaginary 

 difficulties have been raised, such as the supposed swamp- 

 ing of varieties by intercrossing, and so on. It must 

 be confessed that these difficulties seem to have taken 

 root in the mind of even so renowned an evolutionist 

 as Alfred Ptussel Wallace. Now such a view seems to me 

 to be entirely irrational. If we could have been spec- 

 tators of the history of a species through the lapse of ages, 



