ONE OR SEVERAL SPECIES 25 



similarly : " If Negro and Caucasian were snails, the zoologists 

 would unanimously declare them to be two perfectly distinct 

 species that could never have arisen by gradual divergence from 

 a common parent form ". In opposition to this view, the ma- 

 jority of naturalists (Kollmann, Virchow, K. E. v. Baer, Ranke, 

 etc.) agree in classifying man as a single species, their opinion 

 being that the existing differences are not sufficiently distinctive 

 to constitute different species, and hence that it is not a ques- 

 tion of species, but rather of varieties or sub-species. With his 

 customary critical thoroughness Darwin has stated his opinion 

 on the subject so long discussed by the polygenists and mono- 

 genists. The former argue that the various so-called races are 

 found, on careful comparison, to differ importantly from one 

 another, not only on anatomic-physiological lines (texture of 

 the hair, relative proportions of the body, capacity of the lungs, 

 form and cubic content of the skull, convolutions of the brain, etc.) 

 but also on psychological and pathological lines. Now as these 

 characters have persisted for thousands of years, and the different 

 races have adjusted themselves to different climatic conditions, 

 and have even different parasites (Pediculi), we may, without 

 hesitation, infer that man consists of several species, more especi- 

 ally when we remember that certain races are completely sterile 

 when crossed. On the other hand the monogenists, whose 

 theory was supported by Darwin, hold the view that the most 

 distinct races possess a greater resemblance to one another in 

 respect to form than is usually admitted. Further, that the 

 chief distinctive race characters (formation of the skull, features 

 of the face, colour of the skin, and distribution of hair on the 

 body) are extremely variable, and, most important of all, the 

 races graduate into each other. Now it is usual to unite all the 

 forms that graduate into each other under a single species ; hence 

 applying the same principle, there can be but a single human 

 species. This view is supported by the fact that for many 

 centuries the most complex intercrossing of the different races 

 has gone on, and that all races bear a striking resemblance to 

 one another in tastes, manners and customs, expression of the 

 emotions, and the use of weapons and ornament. 



The question as to whether the separate races (sub-species) 

 each originated from a single pair of progenitors has given rise 



