26 
The Ohio Naturalist. 
[Vol. IV, No. 2 , 
long lime to explain that phenomenon and it has been revived in a 
refined, angmented and complex form to stand as the modern 
theory of light. And so, had selection been advanced at first as 
an explanation of diversity in plants and animals, it would have 
meant a far deeper insight into the ways of Nature than the 
Greeks had at that time. 
What, we may ask, is an acquired character? That it is a 
difficult ta.sk to answer this question one may infer from the fact 
that in the periodical Nature for 1895, a discussion, ranging over 
six or .seven numbers and led by some of the greatest workers in 
biology was carried on, each contributor offering a'different defi- 
nition of varying length and complexity. And it is doubtful 
whether the discussion ended because a conclusion had been 
reached or whether no more .space could be given by the publish- 
ers. The most comprehensive definition of the term is that an 
acquired character is a modification of an organism in its ontog- 
eny, produced b}’ reactions to external stimuli. Its opposite is 
the congenital character which arises from the genital cell irre- 
spective of external conditions. Now, obviou.sly, thc.se defini- 
tions involve severe difficulties, if not in themselves, at least in 
their application. Fertile .sake of clearness, let us consider the 
development of an organism in ontogeny and ph\ logen}'. 
The Protozoa or Protophyta cannot be said to have an onto- 
geii}’. Wdratever maj' be said to be the method of reproduction 
in them, we may I'educe it to its .simplest terms — binary fission. 
Consequently, we cannot .speak of ixilingenesis or cenogenesis in 
in the protozoa or protopliyta. Since there is no division of labor 
whereby one portion of the organhsm is .set apart to perform the 
function of nutrition, another for reproduction, etc., we can say 
that the environment exerts a direct effect on the reproductive 
element and the transmission of acquired characters in unicellular 
forms is a reality. Put when we pass the line between the nni- 
cellidar forms and multicellular forms, our i)roblem is different 
Here we have division of labor. One cell has as its special func- 
tion the elimination of waste: another, movement, while the thinl 
reproduces the animal or plant in its entirety. The question 
arises, is the method here the .same as in the unicellular forms? 
Or is there a modification necessary to meet the new conditions? 
In the case of the one celled forms, the environment of the repro- 
ductive element is the environment of the organism as a whole, 
while in the multicellular forms the environment of the germinal 
cell is the group of cells surrounding it — Ox^cnvironmetit oi the mul- 
ticellular orgauisin being the medium outside the body which 
rarely or never comes in contact with the germ cell, at least until 
that cell is mature. Hence the case is different. In the latter 
case — i. e , the multicellular organisms, the generative cell would 
react to such stimuli as are furnished by the surrounding body. 
