124 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 
