Intracellular Pangenesis. 639 
ported particles, there is no further need for their partici- 
pation, and they will simply be eliminated by natural se- 
lection. 
BROOKS maintains that it is not necessary to assume 
special material vehicles for the hereditary characters of 
every leaf or of every flower or of every cell of the body. 
We must simply assume that all similar organs or cells 
are represented by the same unit. The otherwise highly 
complex conception of the structure of the idioplasm is 
thus considerably simplified. 
The work of GALTOX and BROOKS has contributed 
largely to freeing the theory of pangenesis of much use- 
less ballast, and therefore to exhibiting its essence in a 
much purer light; but in regard to one important point 
they still adhere too closely to DARWIX'S old conception 
of the theory. This point is the question whether the 
organs and the cells themselves are the units which we 
o 
must think of as being represented in the idioplasm. 
10. INTRACELLULAR PANGENESIS. 
In contrast to the opinion of the authorities cited in 
the previous section, I assume that the units are not the 
morphological elements, such as the parts of the body 
and tissues, nor the cells and their visible organs. On the 
contrary I assume them to be the internal elementary 
characters which determine the external features of the 
organism, and which must cooperate to build morpholog- 
ical elements (Fig. 147). 
In his books, DARWIN is not always quite clear con- 
cerning what he means by a single heritable character. 
Often he speaks of his particles as representatives of 
cells; at other times other morphological elements or 
