44 EVOLUTION OF TO-DAY. 



of evolution in general, that nature is not forming 

 any new species to-day, but only varieties. This is, 

 however, nothing but an assumption. Among do- 

 mestic varieties it is true that the methods of selec- 

 tion have not succeeded in inducing sterility among 

 the varieties. In some instances, on the contrary, 

 they have probably rendered mutually fertile, forms 

 originally sterile. But the variations have been 

 very great, and have been sufficient to constitute 

 distinct species and genera in every respect except 

 this one of sterility. In the great realm of nature 

 it is impossible to say whether or not new species 

 are being constantly produced. New species are 

 certainly being constantly found. Since the fauna 

 and flora are not thoroughly known in any country, 

 new species may be constantly appearing without 

 the possibility of their being discovered. Even in 

 England, the country whose fauna is best known, 

 new species are occasionally being found. It is only 

 twenty-five years since the matter has been consid- 

 ered so important, and this is too short a time to 

 make negative conclusions of any value. Naturalists 

 are now collecting and carefully studying the spe- 

 cies of various localities, and are slowly gathering 

 data for an answer to this question. When, in another 

 century, naturalists can compare the world which 

 they know, with the record left by naturalists to- 

 day, it may be possible to answer this question. 

 But to-day the problem cannot hope for immediate 

 solution. To state that no new species are now 

 forming, is not only to beg the whole question at 

 issue, but is to make a statement for which the 



