72 The Ottawa Naturalist. [July 



races, ad injinitwml It must not be lost sight of that perfectly 

 natural conditions are necessarily the only ones under which the 

 test of specific relationship is a fair one, as it is well known 

 amongst naturalists that domestication or confinement entirely 

 alters the reproductive abilities even of a large number of the 

 higher animals. This is a fact quite apart from the one that 

 most of the various forms, strains, or "breeds" of our domestic 

 animals, birds, or plants are not "species" at all in the scientific 

 sense, but rather variations specialised b}^ man's careful selection. 

 Under complete domestication specific identity soon becoines 

 entirely lost. . -. ; . .::i-^ -M 



In the foregoing illustration^-, of^ extreme ^geographical or 

 climatic varieties or local races, it;has been assumed that it has 

 been possible to trace relationship i clearly, through from one 

 extreme to the other. When such relationship exists it seems 

 to suggest that the aggregate of all these varying forms should 

 constitute the species. Yet the extremes cannot possibly meet 

 under natural conditions, so that that test cannot be made. Are 

 the extremes to be considered different species? ;! 



There can be little doubt, if Darwin's theory ^,be admitted, 

 that it is through the formation and subsequent isolation of such 

 local races that distinct species have been formed through 

 courses of millions of years. Isolation, whether of climatic 

 changes such as the glacial epoch, or by the formation of con- 

 tinents, inundations by sea, upheavals of mountains, etc., effect- 

 ually prevented the mingling of many races ages ago. which may 

 subsequently have become modified in different ways, and so 

 become quite distinct species from our point of viev/, or non- 

 variable species may have become so divided, and the isolated 

 portions of them have remained similar or nearly similar to our 

 eyes. Through countless ages they have lost their blood-relation- 

 ship, and yet they look alike. Are they to be considered distinct 

 species? These things we can only judge for ourselves from 

 close observation and much study in each particular instance. 



Not only do multitudinous forms occur, perhaps side by side 

 so enormously variable within certain limits, or so exactly like 

 forms of another supposed species found in one-locatily, and like 

 forms of others elsewhere, that without the actual reproductive 

 test we can merely draw deductions from close observation; 

 but probably no two men who have given much thought to the 

 subject have exactly the same idea as to what degrees of difference 

 are necessary, or what exact distance of relationship must exist 

 before two forms can have a right to be called different species. 

 It is unquestionable that many species do exist which show no 

 very close relationship to any others wherever they occur. But 

 a very large number, more particularly amongst insects and 



