WHA T IS A SPECIES f 931 



4. That the essence of the Lirmean conception depends on such ideas is 

 also shown by the following quotations from well-known botauical works : 

 "It is believed that with the general advance of science ... it is at 

 once more philosophical and more practically convenient, as well to the general 

 botanist in the higher branches of the science, as to the more superficial 

 amateur, to retain for the meaning of a species the limits affixed by the original 

 principles of Linnaeus .... A species comprises all the individual 

 plants which resemble each other sufficiently to make us conclude that they are 

 all, or may have been all, descended from a common parent. These individuals 

 may often differ from each other in many striking particulars . . but these 

 particulars are such as experience teaches us are liable to vary in the 

 seedlings raised from one individual. When a large number of the indivi- 

 duals of a species differ from the others in any striking particular, they 

 constitute a variety . . A variety can only be propagated with certainty 

 by grafts . . or any other method which produces a new plant by the 

 development of one or more buds taken from the old one . . A real species 

 will always come true from seed." " s And, again : 



" Linnaeus laid down that each species consists of similar individuals which 

 are related together by their origin, and which are the unaltered descendants 

 of a common ancestor or pair of ancestors. It does not affect the value of the 

 definition that LinnEeus considered these ancestors to be creations of the 'infi- 

 nitum ens ' ; but it is very important that he recognized existing organisms as 

 the continuation, the rejuvenated portion of one and the same living being, so 

 that the species is not a figment of the human mind, but is something 

 which actually has an objective existence. . . Each species has its special 

 features or characteristics, and all individuals possessing these specific marks are 

 said to belong to the same species. Specific characteristics are hereditary, and 

 are transmitted unaltered to the descendants. There are, however, some 

 plant characteristics which are not inherited, but which may appear or not 

 according as the individual develops in this or that place. . . They form 

 the foundation for the existence of the variety, according to Linnaeus."f 



5. From the above we might be led to infer that modern naturalists are 

 generally agreed regarding their conception of a species, but in point of fact 

 nothing is further from being the case, as will be gathered from the two 

 following quotations : — 



(a) " The systematic species are the practical units of the systematists and 

 florists, and all friends of wild nature should do their utmost to preserve 

 them as Linnaeus has proposed them, " J and 



(6) " My friend, Professor E. Ray Lankester, . . is inclined to think 

 that we should discard the word species not merely momentarily but 

 altogether. Modern zoology having abandoned Linnaeus, conception of 



* Handbook of the British Flora, by George Bentham, 1866, pp. 6, 7 and 11. 



f Natural History of Plants, by A. Kerner, Eng. Ed., 1895, Vol. II, pp. 486-487. 



X Species and Varieties, their Origin hy Mutation, by Hugo De Vries, 1905, p. 12. 



