In the first place, it must be definitely understood that we are dealing only with specific, as distinguished from general, transmission. As the germ-cells derive their nourishment from the body, it is obvious that any cause profoundly affecting the latter might in that way exercise an influence on the germ-cells; that if the parent was starved, the germ-cells might be ill-nourished and the resulting offspring might be weak and puny. There is experimental evidence that this is the case; but that is not the inheritance of an acquired character. If, however, a white man tanned by long exposure to the tropical sun should have children who were brunettes, when the family stock was all blond; or if men whose legs were deformed through falls in childhood should have children whose legs, at birth, appeared deformed in the same manner; then there would be a distinct case of the transmission of an acquired characteristic. "The precise question," as Professor Thomson words it, "is this: Can a structural change in the body, induced by some change in use or disuse, or by a change in surrounding influence, affect the germ-cells in such a _specific_ or representative way that the offspring will through its inheritance exhibit, even in a slight degree, the modification which the parent acquired?" He then lists a number of current misunderstandings, which are so widespread that they deserve to be considered here. (1) It is frequently argued (as Herbert Spencer himself suggested) that unless modifications are inherited, there could be no such thing as evolution. Such pessimism is unwarranted. There _is_ abundant explanation of evolution, in the abundant supply of germinal variations which every individual presents. (2) It is common to advance an _interpretation_ of some observation, in support of the Lamarckian doctrine, as if it were a _fact_. Interpretations are not facts. What is wanted are the facts; each student has a right to interpret them as he sees fit, but not to represent his interpretation as a fact. It is easy to find structural features in Nature which _may be interpreted_ as resulting from the inheritance of acquired characters; but this is not the same as to say and to prove that they _have resulted_ from such inheritance. (3) It is common to beg the question by pointing to the transmission of some character that is not proved to be a modification. Herbert Spencer cited the prevalence of short-sightedness among the "notoriously studious" Germans as a defect due to the inheritance of an acquired character. But he offered no evidence that this is an acquirement rather than a germinal character. As a fact, there is reason to believe that weakness of the eyes is one of the characteristics of that race, and existed long before the Germans ever became studious--even at a time when most of them could neither read nor write.