b 
932 The American Naturalist. [October, 
seconded any more than a sensitive plate once used can receive a 
second photographic impression ; nor is it necessary with Mr. Skertchly 
to suppose that the pupa ‘‘notices’’ the color of its surroundings, 
though we do not know whether it is conscious of them or not. 
have myself suggested? that mimetic analogy is to be explained by 
the impression produced on the reproductive elements by a sense 
impression, as in the cases of ** maternal impressions,’’ of which some 
real cases exist. Nor does such a theory require that any ** volition "' 
be present, such as Mr. Poulton ascribed to ** the founder ’’ of Ameri- 
can Neo-Lamarckianism. Such a hypothesis is confirmed by a fact 
mentioned by Mr. Poulton on page 238. He says: “ This example 
enforces a conclusion arrived at by the study of mimetic butterflies in 
all parts of the world,—that the females are far more liable to assume 
this method of defense than the males. Thus Mr, Wallace found that 
the eastern Morphidz and the special group of swallow-tails were only 
mimicked by the females of other swallow-tails ; and similar facts have 
een observed in America." The male young have developed beyond 
the effects of the impression, while the female young have not.— 
E. D. Cope. 
Billet on the Life History of Bacteria.‘—In addition to 
elborate laboratory work with the Cladothrix dichotoma, Bacterium 
balbianit, Bacterium osteophilum, and Bacterium parasiticum, following 
them step by step through the filamentous, dissociated, entangled, and 
zoogleeic states, and giving conclusive proof that the present classifi- 
cation of microbes is erroneous, this work has a bibliographic index of 
662 references, including the names of over four hundred authors. 
The author does much to clear up the history of this subject, and also 
points out clearly that more attention has been paid to the effects upon 
the animal economy than to the morphology. He calls attention to 
the fact that the ** Cohn school ” declares for one unchangeable form, 
and that Zopf merely specifies types according to the forms. 
Billet very properly claims that one form may be derived from 
another, and cites that Ray Lankester first recorded that the forms 
were not sufficient for classification, the latter being confirmed by 
Cienkowski. Billet shows that the bacterium (the short rod form) is 
able to take on sufficient length to represent the bacillus ; that a num- 
ber of these can form chains ; and that the vibrio is found in different 
media to change into the spirillum. He follows the cladothrix through 
: Ben Sirup: Society, 1871, p. 261. Origin of the e p. 213. 
a e orphologie et d: teriacées, par 
Ey s Billet, Docteur en ME Me as OT poiana SA de 
ance et de la Belgique, 1890. 
