JAMES E. THOMPSON-MATERNAL IMPRESSIONS, ETC. 
85 
TRANSMISSION OP MUTILATIONS. 
The subject of “transmission of mutilations” has often been con¬ 
founded with that of maternal impressions, without, in my opinion, due 
regard for the innate causes at work and the mechanism by which each 
particular process exerts its influence. 
A true maternal impression, in the strict definition of the term, exerts 
its influence on the foetus, and not on the ovum before the act of impreg¬ 
nation has been accomplished; with one exception, that in certain 
cases the maternal impression has been so lasting that its effect has reached 
over into the following pregnancy, producing an analagous foetal de¬ 
formity in both cases. 
On the contrary, a transmitted mutilation presupposes that, in conse¬ 
quence of an injury received by the parent (either male or female) at a 
variable period before pregnancy, the offspring comes into the world in¬ 
heriting the same condition that the parent acquired. 
This proposition formed the basis of Lamarck’s theory of transforma¬ 
tion of species. He thought that changes in structure resulted from 
changes in the conditions of life, forcing the animal to assume new habits. 
Certain habits increased or decreased the activity of various organs; 
those organs subject to disuse underwent retrograde changes, whilst those 
whose activity had increased acquired new importance. 
By such a theory Lamarck was able to account for the length of a 
swan’s neck, owing to its custom of seeking food at the bottom of the 
water; also for the disappearance of the eyes of animals or fishes inhabit¬ 
ing caves or subterranean lakes and seas. 
This theory necessarily assumes that of “ transmission of acquired 
characters,” and Lamarck accepted this as a matter of course. 
So did Darwin a few years later, but he added to it the theory of 
“natural selection,” which in the hands of such a truthful, laborious 
genius, forms one of the grandest discoveries of the century. 
It is outside of mj r province to enter deeply into the subject of natural 
selection, for I should commit myself to controversies which would 
occupy more time than I have now at my disposal. I will content my¬ 
self with insisting, that, whilst the doctrine of natural selection is full of 
truths and wonders, that of transmission of acquired characters is not 
proven. The supporters of Lamarck’s doctrine rely mainly on cases of 
transmitted mutilations to prove their case. 
We find on scanning the literature of the subject that Darwin put forth 
certain cases in support of this view. In the “ Descent of Man,” (pp. 
200-311) we find that he attributes the narrowing of the long central 
tail feathers of the Motmot to the effect of habitual mutilation. These 
birds have a habit of biting and removing the feathers from this spot, 
