948 The American Naturalist. [November, 
one another, the greatest possible degree of harmony may be 
reached, and consequently a definite metamorphosis of the 
species involving all the parts of the individual may occur. 
” 
What appears to be new therefore in Organic Selection is, 
first, the emphasis laid upon the almost unlimited powers of 
individual adaptation; second, the extension of such adapta- 
tion without any effect upon heredity for long periods of time ; 
third, that heredity slowly adapts itself to the needs of a race in a 
new environment along lines anticipated by individual adaptation, 
and therefore along definite and determinate lines. This hypo- 
thesis, if it has no limitations, brings about a very unexpected 
harmony between the Lamarckian and ultra-Darwinian (Weis- 
mannian) aspects of evolution by mutual concessions. While 
it abandons the transmission of acquired characters, it places 
individual adaptation first and fortuitous variation second as 
Lamarckians have always contended, instead of placing sur- 
vival conditioned by fortuitous variations first and foremost 
as Selectionists have contended. If true, it is thus a com- 
promise between the pure Lamarckian and pure Darwinian 
standpoints in which the concessions are about equal. And if 
true it gives us at least a partial explanation of determinate 
variation which Lamarckians have recently contended for, 
and Darwinians have strenuously denied.’ 
Professor Alfred Wallace has recently endorsed this hypo- 
thesis in a review of Professor Morgan’s work, “Habit and 
Instinct,” in the March, 1897, number of Natural Science in the 
following language: “Modification of the individual by the 
environment, whether in the direction of structure or of hab- 
its, is universal and of considerable amount, and it is almost 
always, under the conditions, a beneficial modification. But 
every kind of beneficial modification is also being constantly 
effected through variation and natural selection, so that the 
beautifully perfect adaptations we see in nature are the result 
of a double process, being partly congenital, partly acquired. 
è See Osborn: Cartwright Lectures, Present Problems in Evolution and Her- 
edity, 1891. Also, “ Is Variation Definite or Indefinite?” American Naturalist, 
1889. i 
