But beautiful as this explanation would be, I regard it as untenable, because it assumes the _transmissibility of functional modifications_ (so-called "acquired" characters), and this is not only undemonstrable, but is scarcely theoretically conceivable, for the secondary variations which accompany or follow the first as correlative variations, occur also in cases in which the animals concerned are sterile and _therefore cannot transmit anything to their descendants_. This is true of _worker bees_, and particularly of _ants_, and I shall here give a brief survey of the present state of the problem as it appears to me. Much has been written on both sides of this question since the published controversy on the subject in the nineties between Herbert Spencer and myself. I should like to return to the matter in detail, if the space at my disposal permitted, because it seems to me that the arguments I advanced at that time are equally cogent to-day, notwithstanding all the objections that have since been urged against them. Moreover, the matter is by no means one of subordinate interest; it is the very kernel of the whole question of the reality and value of the principle of selection. For if selection alone does not suffice to explain "_harmonious adaptation_" as I have called Spencer's _Coadaptation_, and if we require to call in the aid of the Lamarckian factor it would be questionable whether selection would explain any adaptations whatever. In this particular case--of worker bees--the Lamarckian factor may be excluded altogether, for it can be demonstrated that here at any rate the effects of use and disuse cannot be transmitted. But if it be asked why we are unwilling to admit the coöperation of the Darwinian factor of selection and the Lamarckian factor, since this would afford us an easy and satisfactory explanation of the phenomena, I answer: _Because the Lamarckian principle is fallacious, and because by accepting it we close the way towards deeper insight_. It is not a spirit of combativeness or a desire for self-vindication that induces me to take the field once more against the Lamarckian principle, it is the conviction that the progress of our knowledge is being obstructed by the acceptance of this fallacious principle, since the facile explanation it apparently affords prevents our seeking after a truer explanation and a deeper analysis.