[28] Mr. Platt Ball has, indeed, argued that "use-inheritance would often be an evil," since, for example, "the condyle of the human jaw would become larger than the body of the jaw, because as the fulcrum of the lever it receives more pressure"; and similarly as regards many other hypothetical cases which he mentions. (_The Effects of Use and Disuse_, pp. 128-9 _et seq._) But it is evident that this argument proves too much. For if the effects of use and disuse as transmitted to progeny would be an evil, it could only be because these effects as they occur in the parents are an evil--and this they most certainly are not, being, on the contrary and as a general rule, of a high order of adaptive value. Moreover, in the race, there is a superadded agency always at work, which must effectually prevent any undue accumulation of these effects--namely, natural selection, which every Darwinist accepts as a controlling principle of all or any other principles of change. Therefore, if, as first produced in the life-time of individuals, the effects of use and disuse are not injurious, much less can they become so if transmitted through the life-time of species. Again, Mr. Wallace argues that, even supposing use-inheritance to occur, its adapting work in the individual can never extend to the race, seeing that the natural selection of fortuitous variations in the directions required must always produce the adaptations _more quickly_ than would be possible by use-inheritance. This argument, being one of more weight, will be dealt with in a future chapter.