82 J. W. SLATER, ESQ., F.C.S., F.E.S., ON 



THE AUTHOR'S FURTHER REPLY. 



Dr. BibDLE's remarks on the compatibility of chance (apparent) 

 with design deserves serious attention. It may he mentioned that 

 in the opinion of some authorities — undemonstrated, I must admit, 

 and probably undemonstrable — -the formation of new species or 

 even varieties is at an end. We no Longer witness the origin of 

 new well-marked varieties of mankind, save by the mixture of 

 races which already exist. Perhaps the isolation needed for this 

 end is no longer existent. Rut the development of the European, 

 the negro, and the Mongol from the original human stock — inter- 

 mixture being impossible — seems to present a problem of the same 

 nature as the origin of the tiger, the leopard and the jaguar from 

 one common feline stock. 



Mr. Guppy's studies on the distribution of aquatic and marsh 

 plants are of very high value as the type of a class of researches 

 which onght to be extensively followed up. They are likely to 

 throw useful cross-lights on all theories concerning the origin of 

 species. 



An interesting fact is the career of the Canadian water-weed 

 (Anacharis, or Elodea /). Some years back it was spreading with 

 alarming speed in our rivers and inland navigations. Suddenly it 

 has ceased to multiply and has even died out in very many cases. 

 No known cause has been ascertained. 



Another interesting fact is the spread of the periwinkle. It is 

 asserted by horticulturists and botanists not to ripen its seed in 

 England. Yet we find it growing and spreading in woods where 

 it cannot have straggled away from gardens, and where certainly 

 no one can have taken the trouble to plant it. 



Mr. J. J. Murphy's remarks call for some reply, in fact they 

 make me fear that I have not explained my views with sufficient 

 distinctness. 



The objection that Natural Selection cannot be accepted as the 

 prime cause of the genesis of species seems to me, as to not a few 

 abler men, simply fatal to Darwinism, and is not to be disposed 

 of by the scarcely relevant illustration drawn from the New- 

 tonian theory of planetary movements. I do not reject Natural 

 Selection because I do not know its origin, but because it fails 

 to account for the phenomena. Now, Mr. Murphy's objection to 

 Newton merely raises the question of the origin of gravitation, not 

 urging that, it fails to account for the planetary movements. 

 Hence between the eases there is no parallelism and Mr. Murphy's 

 illustration does not apply. 



