4 THE CASE AGAINST EVOLUTION 



genesis. According to the theory of encasement, the adult 

 organism did not arise by the generation of new parts (epi- 

 genesis), but by a mere "unfolding" {evolutio) of preexistent 

 parts. At present, however, evolution is used as a synonym 

 for transformism, though it has other meanings, besides, being 

 sometimes used to signify the formation of inorganic nature as 

 well as the transformation of organic species. 



Evolution, in the sense of transformism, is opposed to 

 fixism, the older theory of Linne, according to whom no spe- 

 cific change is possible in plants and animals, all organisms 

 being assumed to have persisted in essential sameness of type 

 from the dawn of organic life down to the present day. The 

 latter theory admits the possibility of environmentally- 

 induced modifications, which are non-germinal and therefore 

 non-inheritable. It also admits the possibility of germinal 

 changes of the varietal, as opposed to the specific, order, but 

 it maintains that all such changes are confined within the 

 limits of the species, and that the boundaries of an organic 

 species are impassable. Transformism, on the contrary, affirms 

 the possibility of specific change, and assumes that the boun- 

 daries of organic species have actually been traversed. 



What, then, is an organic species? It may be defined as a 

 group of organisms endowed with the hardihood necessary to 

 survive and propagate themselves under natural conditions 

 {i.e. in the wild state) , exhibiting a common inheritable type, 

 differing from one another by no major germinal difference, 

 perfectly interfertile with one another, but sexuully incom- 

 patible with members of an alien specific group, in such wise 

 that they produce hybrids wholly, or partially, sterile, when 

 crossed with organisms outside their own specific group. 



David Starr Jordan has wisely called attention to the 

 requisite of viability and survival under natural conditions. 

 "A species," he says, "is not merely a form or group of indi- 

 viduals distinguished from other groups by definable features. 

 A complete definition involves longevity. A species is a kind 

 of animal or plant which has run the gauntlet of the ages and 



