scientific value whatever. They can neither be accounted for, nor can they be used to account for anything themselves. Even of twins, though very like each other in many respects, one may be phlegmatic, the other passionate. Some scientists, such as Weismann and others, have therefore denied, and I believe rightly, that any acquired characters, whether physical or mental, can ever be inherited by children from their parents. Whatever similarity there is, and there is plenty, is traced back by him to what he calls the germ-plasm, working on continuously in spite of all individual changes. If that germ-plasm is liable to certain peculiar modifications in the father or grandfather, it is liable to the same or similar modifications in the offspring, that is, if the father could become a drunkard, so could the son, only we must not think that the _post hoc_ is here the same as the _propter hoc_. If we compare the germ-plasm to the molecules constituting the stem or branches of a vine, its grapes and leaves in their similarity and their variety would be comparable to the individuals belonging to the same family, and springing from the same family tree. But then the grape we see would not be what the grape of last year, or the grape immediately preceding it on the same branch, had made it, though there can be no doubt that the antecedent possibilities of the new grape were the same as those of the last. If one grape is blue, the next will be blue too, but no one would say that it was blue because the last grape was blue. The real cause would be that the molecules of the protoplasm have been so affected by long continued generation, that some of the peculiar qualities of the vine have become constant. The child of a negro must always be a negro; his peculiarities are constant, though it may be quite true that the negro and other races are not different species, but only varieties rendered constant by immense periods of time. What the cause of these constant and inconstant peculiarities may be, not even Weismann has yet been able to explain satisfactorily.