196 SPECIES AND VARIETIES. 



type have no power to change this type, and that the existence 

 of the aberration is merely a temporary one. 



According to the opinion, of the systematists, species are 

 realities, real groups of organisms of which the majority are 

 true to type, conforming to the description of the type-speci- 

 men. Species are thought to be unchanged, the species which 

 existed as such long years ago are believed to be identical with 

 their ancestors, and it is believed that if a number of species we 

 now know, will not become extinct, they will be found un- 

 changed after many years. 



Species, according to the systematicians differ from each 

 other in groups of characters, varieties on the other hand do 

 not have the permanency of species. They differ from the spe- 

 cies to which they belong in one striking point, and they are 

 continually being produced by the species, they have no conti- 

 nuity in themselves. 



A variety is a description of such individuals which are occas- 

 ionally found within a species, which differ enough from the 

 type to warrant a new and common name. Varieties do not 

 commonly procreate themselves for any number of gener- 

 ations. 



De Vries tried to find a genuine distinction between what 

 constitutes species and what are varieties. According to him, 

 species differ from each other in presence and absence of pan- 

 genes, whereas the difference between a species and its variety 

 or between varieties would be due to different states of the 

 same pangene, patency and latency. The result would be, that 

 hybrids between varieties or between a species and a variety 

 would "Mendelize," whereas species-hybrids would be stable, 

 and would show no segregation of genes in following gener- 

 ations. We know now, that no such difference can be demon- 

 strated. All the evidence points to it that all such differences 

 as are inherited are always the result of differences in zenotype, 

 of presence and absence of genes. And a biomechanical view of 

 inheritance excludes states of patency or latency of genes. Ac- 

 cording to Darwin, species change under the influence of natur- 



