124 '^^^ DOCTRINE OF DESCENT. 



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

 lated the doctrine of Descent, and in 1804 actually pro- 

 pounded all the propositions which Darwin has con- 

 structed afresh and more completely. Lamarck proclaimed 

 that it is merely our limited powers of comprehension 

 that demand the erection of systems, whereas all sys- 

 tematic 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 re- 

 semble those from whom they descend. But these indi- 

 viduals belong to infinitely divergent races, which con- 

 tinue so long as they are unaffected by any cause produc- 

 ing 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 succes- 

 sion 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 

 short as to give rise to the vulgar and false hypothesis 

 of stability and immutability. The transformation is ef- 



