(eee) 
they represent the highest achievement of natural selection in. 
the protective colours of insects. If these variable colours 
represented the beginnings of ordinary fixed colour variations 
the species would lose and not gain by the change. The essence 
of the protective value is the power of being concealed in each of 
several different environments, and hereditary transmission of 
the results would only injure the individuals of the next 
generation. The intricacy of the processes by which the 
stimulus gives rise to each appropriate colour-effect is no 
difficulty to the interpretation based on natural selection— 
‘fan agency capable of dealing with complex physiological 
relationships in precisely the same way that it deals with all 
other kinds of variations.” * 
The barren conception of “ self-adaptation,’’—the hypothesis 
that organisms possess a constitution which compels them to 
react adaptively, breaks down when we find the adaptation is 
only possible by means of a specialized and complex train of 
physiological sequences. 
We must remember that the species we investigate are 
“heirs of all the ages,” thoroughly inured to experimental 
research, past masters in the art of meeting by adaptive 
response the infinite variety of stimulus provided by the 
environment, If we remember this we shall always be on 
our guard against a too hasty interpretation based on the 
fundamental properties of protoplasm.t 
The hypothesis that organisms are so buiJt that they must 
produce useful variations, seems to be little more than the old 
“internal developmental force,” or ‘‘innate tendency towards 
perfection,” ina modern dress. Furthermore, a consideration of 
the essential meaning of adaptation proves the futility of any 
such attempt at explanation. The ultimate object of adapta- 
tion is to obtain food, to escape enemies, or to subserve 
reproduction. The most conspicuous adaptations manifested 
by an individual are relative to the condition of the organic 
environment with which its contact is in many respects 
* Professor Meldola in ‘‘ Nature,” vol. xxxviii, 1888, p. 389. See also 
Professor Meldola’s Presidential Address in Proc. Ent. Soc. Lond., 1896, 
pp. Ixx, Ixxi; and the first scientifie paper published by him, viz. Proc. 
Zool. Soc. 1873, p. 153. 
t ‘‘ Nature,” vol. Ixxi, 1905, p. 244. 
