Apr., 1890 . 
THE THEORY OF HEREDITY. 
93 
into facts and interpretation of facts, and the class of facts 
brought forward by Dr. Collier are certainly not opposed to 
Weismann’s theory. Dr. Collier has missed a vital point in 
that theory by neglecting to analyse the concept “ acquired 
character.” In the production of an acquired character 
there are two sets of forces at work—the action of the 
environment (in the case of diseases—virus, bacillus, bad 
habit, climatic condition), and the constitution. What Weis- 
mann holds is that the constitutional part, like any other 
organic character, may be transmitted and inherited. The 
part due to the direct action of the environment is not 
inherited. As an acquired character is due to two factors— 
one inherited and one not—an acquired character is not 
inherited. In the case of one individual, the pleasures of 
the table give rise to that condition of the liver which Dr. 
Collier says causes the symptoms of gout; in another man 
they will cause an apoplectic habit of body; in a third an iron 
constitution will resist any excesses. Similarly the action of 
so specific a virus as the virus of syphilis or of small-pox acts 
very differently on different constitutions. It is the tendency 
to be influenced in the same way by the same outer causes 
that is transmitted or inherited. And it is this descent of 
constitution that causes the family histories of gout or of 
haemophilia. That a constitutional disposition and not an 
acquired effect is transmitted is specially clear in the case of 
bleeders. For them the scratch or pulling of the tooth is 
quite out of proportion to the resulting bleeding. The 
absence of exciting cause, the peculiar dormant transition 
through the females, are clear indices of the constitutional 
and hence inheritable nature of the affection. 
In the case of consumption, it is clear that a child, with 
both parents consumptive, would have the greatest possible 
chance of inheriting a constitution unable to resist the 
organism associated with the disease. It must, however, be 
noted that direct infection is a large factor in family diseases, 
and hence in medical statistics. 
The virus of a disease, or the specific germ, may pass 
with the reproductive cells from either parent to the embryo; 
they can hardly escape passing from mother to developing 
embryo. The extreme case of risk of direct infection is 
reached when a child is born of consumptive parents. Even 
if it inherit from a remoter ancestor unusual constitutional 
resistance to phthisis, from its conception till it leaves the 
parental roof it is in an environment impregnated with the 
bacillus of consumption. 
