312 
to the descendant of these parental charac- 
teristics which have also been acquired is 
the clearest proof of the heredity of acquired 
characteristics. 
In spite of all his objections to the theo- 
retical part of Himer’s work, Minot allows 
that the ‘ Butterflies’ are “valuable from 
the standpoint of the systematic entomolo- 
gist, since his groups are natural ones and 
his grouping of the species is in the main 
correct.”’ 
In his grouping of the butterfly species 
Eimer was guided by those laws which his 
study of the markings of other groups of 
animals had caused him to regard as the 
general rule, and which he therefore con- 
siders himself entitled to apply hypothetic- 
ally to butterflies. The grouping of species 
being admitted by Minot to be natural, this 
is sufficient proof of the correctness of those 
theories which this grouping presupposes. 
In designating those groups as natural ones 
in which longitudinally striped forms de- 
velop into spotted, transversely striped and 
unicolored ones, Minot acknowledges the 
law of evolution of markings in its full sig- 
nificance. 
Darwin, himself, in his ‘ Origin of Species,’ 
employs similar proofs to show that the 
same groups of pigeons are descendants of 
Columba livia. Their phylogenetic connec- 
tion is to him proved by the fact of elements 
of the markings of Columba livia appearing 
in the plumage of our tame pigeons. 
The ontogenetic development of those 
groups of animals the markings of which 
Eimer has studied is to him a valuable 
argument for the correctness of the law laid 
down for their phylogenesis. Similar in- 
vestigations made by H. Haase on the evo- 
lution of the markings on the wings of the 
chrysalis of Papilio Podalirius, in so far as 
his limited materials permitted decisive 
conclusions, completely confirm Himer’s as- 
sertions. 
These and other researches on the same 
SCIENCE. 
(N.S. Vou. VI. No. 139. 
subject led me to make similar investiga- 
tions, the results of which I am about to 
publish. They furnish the best proofs for 
the laws found by Eimer. My specimens 
showed that not only single characteristics 
develop in the way described by Eimer, but 
that the markings of Papilio Podalirius or 
Machaon, as a whole, undergo an evolution 
in which the degrees of Alebion, Glycerion 
or the Turnus group are clearly distin- 
guishable. 
Tt would be of great interest to investi- 
gate the American forms of Papilio in order 
to see whether Himer’s ‘bold hypotheses,’ 
as Minot calls them, apply here. On the 
basis of arguments which have hitherto been 
considered customary and convincing in 
biology, I believe I have shown that Eimer 
far from rejecting Darwin’s theory as a 
whole, because ‘it does not explain the 
origin of variations.’ He knows as well as 
Minot that Darwin does not even attempt 
an explanation of their origin. As, how- 
ever, the theory of the origin of species 
demands an explanation of the origin of 
new characters, Darwin has not, as Himer 
shows, explained that which he wished to 
explain. Himer, on the contrary, shows in 
the ‘ Butterflies ’ how new qualities develop; 
he explains the causes of their formation 
and traces the laws of their development. 
This necessarily led to his well founded 
theory of the origin of species by means of 
variations and their propagation. The 
arguments contained in the ‘ Butterflies’ 
must convince anybody who examines them 
somewhat more closely than Minot, that, 
as Eimer shows, variations and, therefore, 
the origin of species do not take place arbi- 
trarily in the most varied, but accord- 
ing to Orthogenesis in a few absolutely 
definite, directions, not influenced by 
any sort of natural selection and with- 
out any reference to teleology. Eimer’s 
theory of orthogenesis, proved as it is by 
facts, certainly negatives the function of 
