I VABIATION UNDER NATURE 87 



forms. His general tendency will be to make many spe- 

 cies, for he will become impressed, just like the pigeon 

 or poultry fancier before alluded to, with the amount of 

 difference in the forms which he is continually studying; 

 and he has little general knowledge of analogical variation 

 in other groups and in other countries by which to cor- 

 rect his first impressions. As he extends the range of his 

 observations, he will meet with more cases of difficulty; 

 for he will encounter a greater number of closely-allied 

 forms. But if his observations be widely extended, he 

 will in the end generally be able to make up his owii 

 mind; but he will succeed in this at the expense of ad- 

 mitting much variation — and the truth of this admission 

 will often be disputed by other naturalists. When ho 

 comes to study allied forms brought from countries not 

 now continuous, in which case he cannot hope to find 

 intermediate links, he will be compelled to trust almost 

 entirely to analogy, and his difficulties will rise to a 

 climax. 



Certainly no clear line of demarcation has as yet been 

 drawn between species and sub-species — that is, the forma 

 which in the opinion of some naturalists come very near 

 to, but do not quite arrive at, the rank of species: or, 

 again, between sub-species and well-marked varieties, or 

 between lesser varieties and individual differences. These 

 difEerences blend into each other by an insensible series; 

 and a series impresses the mind with the idea of an 

 actual passage. * 



Hence I look at individual differences, though of small 

 interest to the systematist, as of the highest importance 

 for us, as being the first steps toward such slight varie- 

 ties as are barely thought worth recording in works on 



