COX ON THE FOUNDER OF THE EVOLUTION THEORY 235 
each of them. I am now convinced that I was in error in this respect, and 
that in reality only individuals exist in nature.” 1 This I take to mean that 
he formerly thought species were the units and immutable but that now he 
considers the unit to be the individual and species to be a convenient formula 
for instable and somewhat indefinite groups. He speaks in another place 
of Nature’s causing individuals to acquire or lose their qualities by the in¬ 
fluences of environment, by the predominant employment of certain organs 
or the continued lack of use of some parts. He frequently dwells on the 
preeminent importance of the individual in the evolutionary process and 
leads one to believe that this process is not operative beyond the limits of 
the groups called species, genera, etc.; that is to say, it is not clear from his 
writings that he regarded evolution as brought about by the actual trans¬ 
mutation of species, genera, etc., one into another. While he recognizes 
“a series of groups forming a true chain” and “a shaded gradation in the 
complication of structure,” he explains that he does not mean to speak of a 
linear and regular series of species or even genera, for, as he declares, “such 
a series does not exist.” But finally, he appears to have adopted the idea 
of the animal kingdom as constituting “a branching series,” and it is claimed 
for him that he was the first “to sketch out a genealogical tree.” The 
word sketch is quite strong enough to describe his action, for on this point, 
as on many others, he offered bare suggestions or hints without entering 
enough into detail to show that he had thought the subject out to a definite 
conclusion, as Darwin did subsequently. 
The whole problem of the transformation of species rests upon the question 
of the origin of adaptive variations, and, notwithstanding Lamarck’s attempt 
to account for variation by the compelling influence of the environment, 
and notwithstanding all the research which has been directed towards the 
solution of this problem since Lamarck’s day, “the question of how the 
straight line of exact hereditary repetition may be caused to swerve in a 
definite direction to reach an adaptive point” remains, as Professor Eigen- 
mann has remarked, “the question of the present generation, perhaps of 
the entire twentieth century.” 2 
Although neither Lamarck nor Darwin settled this question, the different 
ways injwhich they dealt with it is a point of departure for their two systems. 
While it is true that Lamarck made no attempt to follow up the primary 
causes of variation to the internal organization of the individual, he did 
believe that external conditions were capable of exciting variability in an 
organism so that, through its response to the demands made upon, it by its 
environment, what must needs be would be. Darwin, on the contrary, 
held that variation was, as far as human insight could go in his day, fortuitous, 
1 A. S. Packard, “Lamarck the Founder of Evolution,” p. 249. 1901. 
2 Essay on “Adaptation,” in “Fifty Years of Darwinism,” p. 191. 1909. 
