Amongst those who were pioneers are Galton and Weismann, and, curiously enough, in England and Germany these two men, independently of each other, came to the same conclusion respecting the non-inheritance of acquired qualities, and pointed out that the facts of development indicate that the generative matter is passed on from one generation to another, remaining intact in the body of the parent, and that we have no reason to suppose that it could be influenced by changes in other parts of the parental organism. It is not uninteresting to note and contrast in these two investigators the action of the typically English and typically German mind, more especially as the comparison is perhaps equally complimentary to the two nationalities, and indicates the value of results arrived at by workers of different individualities. Galton was first in the field, and as long ago as 1876[6] made the following clear and concise statement:--“The conclusion to be drawn from the foregoing arguments is that we might almost reserve our belief that the structural cells can react on the sexual elements at all, and we may be confident that at most they do so in a very faint degree: in other words, that acquired modifications are barely, if at all, inherited in the correct sense of the term.” Thirteen years later[7] he expresses himself in practically the same terms. An untiring investigator, chiefly in the facts of human heredity, he briefly sums up as above one of his most important general conclusions. It is all he has to say, it is all that his facts permit him to say. In 1882, Weismann[8] questioned whether there is as yet any proof that acquired characters are transmitted; he writes:--“The theoretical conception of variation as a reaction of the organism to external influences has also not yet been experimentally shown to be correct. Our experiments are still too coarse, as compared with the fine distinctions which separate one individual from another, and the difficulty of obtaining clear results is greatly increased by the circumstance that a portion of the individual difference always depends upon heredity, so that it is frequently not only difficult, but absolutely impossible, to separate those which are inherited from those which are acquired.” Since that time, Weismann, in a series of important essays,[9] indicating a profound knowledge not only of comparative morphology, but of the habits and modes of life of a vast number of animals and plants, has shown that many of the cases which Darwin was doubtful about may reasonably be explained by selection, and he has marshalled a vast mass of evidence in support of the argument that acquired characters, experimentally produced, are not transmitted.