New Characters in Phlogeny 217 
for each variation of the germ substance to appear or 
to become active, either from the beginning, or at any 
time at all during the ontogeny? 
“The phenomena of latency” says Osborn, “speak 
absolutely against Weismann’s conception, according to 
which phylogenetic development would take place in the 
germ plasm by selection of advantageous elements, and 
elimination of disadvantageous elements. These phe- 
nomena of latency indicate that the phylogenetic process 
does not consist in an elimination but in a shoving of 
certain characters into the background (Zurickdrangung) 
during the later stages of ontogeny.” 
Osborn cites as example the well known experi- 
ments of Cunningham on the color of the asymmetrical 
flat fishes, pleuronectids, on whose lower colorless side 
artificial illumination is followed by a reappearance of the 
pigment disposed in the same designs and in the same 
colors as on the upper side, and also Agassiz’s experi- 
ments according to which the young of these same fishes 
retain their original symmetry when they are kept at the 
surface of the water for a longer time than under normal 
conditions. “According to these experiments,’ Osborn 
says very rightly, “progressive inheritance (and so phylo- 
geny) appears to represent rather a process of substitu- 
tion or of addition than one of true elimination in Weis- 
mann’s sense.” 16° Thus these facts also speak in favor 
of the conception that phylogeny rests upon an addition 
of new characters and their superimposition upon the old. 
We can see that to explain by the inheritance of ac- 
quired characters this addition of a new character to the 
%4Qcborn: Alte und neue Probleme der Phylogenese. Ergebn. 
d. Anat. 1 Entwicklungsgesch., herausg. v. Merkel u. Bonnet. Bd. 
III. 1893. Weisbaden, Bergmann, 1894. P. 610, 619. 
