438 THE POPULAR SCIENCE MONTHLY. 



the farthest no other actions of the ganglion - cells in the nervous 

 system of these animals are possible than those which serve their par- 

 ticular, instinctive actions. As the artisans from IsTewcastle-on-Tyne, 

 at the Bureau of Emigration of New York, replied to the question 

 what kind of work they understood, " Packing files," so animals with 

 a perfected instinct purchase their superiority with a one-sidedness 

 which, because they can learn no more, makes them appear as if they 

 had never learned. 



Susceptibility to exercise first enters into the animal world when 

 the maintenance of the individual and the species has been so assured, 

 through outer and inner circumstances, that the creature does not need 

 a further particularly one-sided development. We are, then, free to 

 conceive, with an appearance of justification, that the strength of the 

 muscles employed in flight and digging, the thickened epidermis on 

 the palms of the hands and the soles of the feet, the callus on the pre- 

 hensile tail and the buttocks of apes, the bone-prominences at the 

 attachments of the muscles, and many other similar things, depend 

 on the inherited consequences of nutritive and formative stimulation, 

 while the most diversified kinds of skill may be traced back to inher- 

 ited concatenations of actions of the ganglion-cells ; and this, whether 

 we consider the waves which flow along apparently in a purely mechan- 

 ical manner in the gymnotus-fin, or in the thousand feet of the wood- 

 louse ; or the intelligent posture of the French pointer, which, un- 

 taught, and without ever having seen one before, points at the lizard 

 in the sub-tropical shrubbery as his ancestors pointed at the partridge 

 on the plain of St. Denis. With Mr. Herbert Spencer meeting me in 

 the 6ame thought, which I believe, however, I have more sharply 

 grasped, I deduced on a former occasion how, in such transmissibility 

 of educationally derived aptitudes, possibly lies the reconciliation of 

 the great antitheses of the theory of knowledge of the empirical and 

 the innate views. 



Besides improvement by exercise, improvement by natural selection 

 should not be left out of the account, if we would understand the 

 adaptability of organic nature, for a threefold reason : First, there 

 are numerous adaptations I mean only the so-called sympathetic col- 

 orings for which natural selection, not exercise, seems to afford an 

 explanation. Secondly, plants, which are not less adaptable in their 

 w T ay than animals, do not enjoy exercise. A few phenomena of plant- 

 life, reminding us of callus, and traceable back to nutritive and forma- 

 tive stimulation, belong rather to the region of healing and restora- 

 tion, which is at this point closely connected with exercise. Thirdly, 

 and finally, we require natural selection in order to explain the origin 

 of the adaptability to exercise itself. 



Indeed, the usefulness of exercise in its most diversified forms is in 

 itself a deep problem. If we do not concede, as we can not scientific- 

 ally, that the adaptive quality originated otherwise than mechan- 



