[24 THE DOCTRINE OF DESCENT. 



was restored to merited honour by Darwin, but more 

 especially by Haeckel, and quite recently in France by 

 Ch. Martins. This is J. B. Lamarck, who first formu- 

 lated the doctrine of Descent, and in 1804 actually 

 propounded all the propositions which Darwin has con- 

 structed afresh and more completely. Lamarck pro- 

 claimed that it is merely our limited powers of compre- 

 hension that demand the erection of systems, whereas 

 all systematic definitions and gradations are of artificial 

 nature. We may be assured that nature has produced 

 neither orders, families, genera, nor immutable species, 

 but merely individuals which succeed one another, and 

 resemble those from whom they descend. But these 

 individuals belong to infinitely divergent races, which 

 continue so long as they are unaffected by any cause pro- 

 ducing alteration. Starting from species, like ourselves, 

 he demonstrates their instability. From comparisons of 

 the facts of hybridization and the formation of varieties, 

 he inferred " that all organizations are true productions 

 of Nature, gradually evolved in the course of a long suc- 

 cession of ages ; that in her progress, Nature began, and 

 even now always begins again, with the formation of the 

 simplest organic bodies, and that she directly forms these 

 only, namely, those lowest living beings which have been 

 designated as spontaneous generations." 



Variations and transformations supervene, according 

 to Lamarck, through external influences ; in the lapse 

 of ages they become essential differences ; so that, after 

 many successive generations, individuals which originally 

 belonged to another species ultimately find themselves 

 converted into a new one. The limited period of our 

 existence has accustomed us to a standard of time so 



