The Ohio f^aturalist, 
PUBLISHED BY 
The Biological Club of the Ohio State University. 
Volume XIII. JANUARY, 1913. No. 3. 
TABLE OF CONTENTS. 
Bant.v and Goktner— Induced Modifications iu Pigment Development in Spelerpes 
Larvae. 49 
Gormley— The Violets of Ohio.56 
Mark—N otes on Ohio Moses. .62 
C'laassen —List of Plants Collected in Cuyahoga County and New to this County 
or to Ohio . 64 
Li 
NEl 
POT 
a a 
INDUCED MODIFICATIONS IN PIGMENT DEVELOPMENT 
IN SPELERPES LARVAE.* 
(Preliminary Paper) 
A. M. Banta and Ross Aiken Gortner. 
(From the Station for Experimental Evolution, The Carnegie Institution 
of Washington.) 
Introduction. 
We present here a brief account of a series of experiments 
having as their aim the inhibition, or the modification of pigment, 
development. 
We believe that it is a fairly well established fact that the 
black melanic pigment results from the interaction of an oxidizing 
enzyme of the tyrosinase type and some oxidizable chromogen, 
the exact nature of which has never been elucidatedf. One of us, 
(Gortner 1911, b,) has shown that certain organic phenols inhibit 
the action of tyrosinase in the test tube and the suggestion was 
made that perhaps certain types of colorless animals owe their 
lack of pigment to the presence of inhibitory compounds. The 
present series of experiments was carried out in order to test the 
inhibitory powers of the m. di-hydroxy phenols in vivo as contrasted 
with their action in vitro. 
The material upon which the experiments were carried out, 
consisted of eggs and embryos of the salamander, Spelerpes 
bilineatus, Green. This material is unusually suitable for such 
work inasmuch as the eggs contain no pigment when deposited, 
and the early stages of pigmentation in the embryo can thus be 
followed from day to day. 
* Presented at the annual meeting of the Ohio Academy of Science, 
Columbus, Nov. 30, 1912. 
t For literature see Kastle (1910), Riddle (1909), and Gortner (1911, a). 
49 
