10 
TRANSACTIONS OF THE TEXAS ACADEMT OF SCIENCE. 
the nuclear substance in the cell-division not been positively disproved; 
if, as the theory now stands, it can be clearly shown that its logically 
necessitated assumptions are untenable, it follows inevitably that the 
original conception which necessitated them must be itself untenable. 
The germ-plasm or idioplasm derived from the parent is, according to 
Weismann, composed of a number of aggregated Ids believed to be incor¬ 
porated in the chromosomes. An Id is held to contain, grouped in def¬ 
inite order, the full assortment of vital units, which by self-multiplica¬ 
tion, and the determining influence of certain of its groups have to 
evolve the adult organism. These most efficient vital units, of which 
the Id is supposed to be composed, are called by Weismann Biopliores. 
As their name indicates, they are constituted bearers of the vital prop¬ 
erties. It is conjectured that these life-bearers were originally of equal 
consistency, but have in the course of organic evolution come to vary 
among themselves to such an extent as to be efficient to serve singly and 
collectively as bearers of all the manifold qualities which distinguish 
one cell from another—a brain-cell, for instance, from an epithelial cell. 
And as nothing but nutritive material can possibly enter into the vital 
units of the germ-plasms from outside, the developmental differentiations 
of the Biopliores, so astonishingly significant in relation to the life of the 
organism as a whole, can be solely due to the natural selection of acci¬ 
dental nutritive modifications affecting the chemical structure of the 
Biopliores composing the Ids. 
Here the first fatal flaw of the theory starts into view. For Weismann 
conceives not only the nuclear plasm to be composed of Biophores, but 
also the cellular plasm. Now it is evident, that if the Biophores of the 
nuclear plasm are apt to vary, offering thus favorable opportunities to 
natural selection, surely the Biophores of the cellular plasm must also be 
allowed to vary, and to offer selective chances; for they are exposed to 
exactly the same nutritive and selective influences. The nuclear sub¬ 
stance thus deprived of its exclusive privilege of being the carrier of the 
differentiated properties of the complex organism, can no longer fulfil its 
appointed mission as sole reproductive substance. The germ-plasm the¬ 
ory is therewith proved to be self-destructive. 
Furthermore, leaving for brevity’s sake out of sight all the fanciful 
modes of grouping, multiplication, and division Biophores have to un¬ 
dergo in order to accomplish their assigned task, let us examine for a 
moment in what way Weismann makes those special groups of Biophores 
called Determinants exceed their determining influence. Determinants 
are believed to be the agents which impart to cells their sundry specific 
qualities. Weismann seems to think that it is sufficient to call these spe¬ 
cific agents “ Determinants” in order to settle the matter. We may, 
however, be pardoned for showing some curiosity as to how this aston- 
