468 The Journal 
present known of the facts of heredity.” 
“Looked at critically in the light of 
what we now know about heredity and 
variation, the mimicry hypothesis is 
an unsatisfactory explanation of the 
way in which these remarkable resem- 
blances between different species of 
butterflies have been brought about.” 
PUNNETT’S EXPLANATION 
Punnett’s own explanation tends to 
bring mimicry into the field of mutation 
and Mendelian heredity. He suggests 
that the number of different inherited 
factors for pattern and color, in butter- 
flies, is quite limited, so that the same 
assortment may not infrequently be 
brought together even though the 
group whose members exhibited the 
resemblance might, owing to structural 
differences, be placed in different 
families. In support of this he cites 
the analogy of the rodents, where the 
number of different hereditary factors 
for coat color is small, and the same 
colors may be found in the rabbit, the 
mouse and the guinea-pig. 
“On this view the various color 
patterns found among butterflies de- 
pend primarily upon definite hereditary 
factors the number of which is by no 
means enormous. Many of these fac- 
tors are common to several or many 
different groups, and a similar aggre- 
gate of color factors, whether in an 
Ithomiine, a Pierid, or a_ Papilio, 
results in a similar color scheme.” 
When a case of mimicry is thus estab- 
lished, practically by accident, natural 
selection may perhaps preserve it; but 
natural selection in this view can re- 
ceive no credit for creating the mimicry, 
as the older naturalists thought. This 
explanation is of course largely hypo- 
thetical, and Punnett does not pretend 
that the evidence is sufficient to prove it. 
of Heredity 
One can hardly deny, however, that 
he has made out a strong case against 
the omnipotent adequacy of natural 
selection to explain mimicry in butter- 
flies. And the book is significant as an 
expression of the widespread modern 
objection to the allmacht, the all- 
sufficiency of natural selection as a factor 
in evolution, which marked the pre- 
ceding generation and which still char- 
acterizes many popular writers and 
even a large number of biologists who 
are working in other fields and not in 
touch with the developments of genetics. 
It was once thought that, if an adap- 
tation appeared to be useful to the 
individual, natural selection could be 
invoked to account for its origin. 
Most geneticists now want to be shown. 
It is clear to them that natural selec- 
tion might preserve a case of mimicry, 
but it is not clear to them that it could 
build up a case of mimicry, starting 
with merely trivial variations. 
Natural selection as a factor in evolu- 
tion is probably more firmly established 
today than ever before. But its place 
is also more sharply defined than ever 
before, and it is no longer universally 
admitted to be responsible for creating 
adaptations. Many biologists reached 
this standpoint years ago, and the 
attacks being made on one strong- 
hold after another of the extreme 
selectionists have been successful. The 
attack on the natural selection ex- 
planation of mimicry in_ butterflies 
is only one of a long series which 
has resulted in giving a much clearer 
understanding of what natural selec- 
tion can do and what it cannot do. 
For this reason, as well as for its own 
interest, Prof. Punnett’s book deserves 
wide consideration. 
Research in Inebriety 
A research foundation has been organ- 
ized at Hartford, Conn., under the direc- 
torship of Dr. T. D. Crothers, the object 
of which is to make a scientific study of 
alcoholism and inebriety. The founda- 
tion is to be endowed and will become 
a permanent institution. Appeals are 
to be made to physicians all over the 
country to furnish records and histories 
of cases in order that they may be classi- 
fied and studied for the purpose of 
determining the laws that govern in- 
ebriety outside of the direct effects of 
alcohol. The institution will serve a 
practical end as well as becoming a center 
for research.—Engenical News. 
