There is finally one group of facts often brought forward against Lamarckism by Darwinian authors[158] which may be called the logical *experimentum crucis* of this doctrine, an *experimentum* destined to prove fatal. You know that among the polymorphic groups of bees, termites, and ants, there exists one type of individuals, or even several types, endowed with some very typical features of organisation, but at the same time absolutely excluded from reproduction: how could those morphological types have originated on the plan allowed by the Lamarckians? Of what use would “judgment” about means that are offered by chance and happen to satisfy needs, be to individuals which die without offspring? Here Lamarckism becomes a simple absurdity, just as Darwinism resulted in absurdities elsewhere. [158] It has also very often been said by Darwinians that Lamarckism is only able to explain those cases of adaptedness which relate to active functioning but not mere passive adapted characters, like “mimicry” for example. But this argument *taken by itself*, it seems to me, would not be fatal to Neo-Lamarckism in the special form August Pauly gave to this doctrine. We were speaking about dogmatic Darwinism then, and it is about dogmatic Lamarckism that we are reasoning at present; both theories must fall in their dogmatic form, though a small part of both can be said to stand criticism. But these two parts which survive criticism, one offered by Lamarck, the other by Darwin, are far from being a complete theory of transformism, even if taken together: they only cover a small area of the field concerned in the theory of descent. Almost everything is still to be done, and we may here formulate, briefly at least, what we expect to be accomplished by the science of the future. 4. THE REAL RESULTS AND THE UNSOLVED PROBLEMS OF TRANSFORMISM What has been explained to a certain extent by the two great theories now current is only this. Systematic diversities consisting in mere differences as to intensity or number may perhaps owe their origin to ordinary variation. They may at least, if we are entitled to assume that heredity in some cases is able to hand on such variations without reversion, which, it must be again remarked, is by no means proved by the facts at present. Natural selection may share in this process by eliminating all those individuals that do not show the character which happens to be useful. That is the Darwinian part of an explanation of transformism which may be conceded as an hypothesis. On the other side, congenital histological adaptedness may be regarded hypothetically as due to an inheritance of adaptive characters which had been acquired by the organism’s activity, exerted during a great number of generations. That is the Lamarckian part in the theory of descent.