814 



SCIENCE. 



[N. S. Vol. VII. No. 181- 



thus deprives science of its necessary foot- 

 ing upon observation. If the criticism be 

 just as applied to those who ha.ve sought to 

 escape from the crudities and limitations of 

 materialistic theories, it certainly should be 

 recognized that there is no reason why the 

 believer in dynamism should not scrutinize 

 the pictures presented by histology as care- 

 fully as his colleague who ascribes to matter 

 all the phenomena that science recognizes 

 in cellular biology. In fact, the dynamist 

 should have greater interest in the details 

 of such appearances, for he may believe that 

 every curve must be the function of a dy- 

 namic problem and that every change is the 

 resultant of the composition of forces which 

 are the very realities with which he has to do. 

 In no field have the results of too implicit 

 reliance on the structural categories worked 

 more plainly to retard progress than in 

 neurology. It seems to be assumed that 

 after nervous mechanisms were differenti- 

 ated in the animal kingdom all other parts 

 of the body at once and forever lost their 

 original quota of what may be termed the 

 power of vital equilibrium. When the pre- 

 eminent adaptation of the nervous system 

 to the function of correlation was recognized 

 it was not unnatural that the inherent ten- 

 dency to vital coordination on which the 

 coherence of the body depends during its 

 entire life should be minimized or ignored. 

 Especially when the application of the 

 methylen blue and silver impregnation re- 

 vealed a hitherto unexpected wealth of 

 nervous connections, it was natural to 

 think of the body as linked together by a 

 complete nervous mechanism to such an 

 extent that all coordinations are dependent 

 on the persistence of the nervous contin- 

 uum. Even admitting the practical ubiq- 

 uity of nervous elements within the body, 

 sundry curious coordinations remain to be 

 explained apart from any known basis of 

 nervous control. It may sufiBce to mention 

 the following : It is evident that during 



the embryonic stages of higher animals, as 

 well as throughout the life of many lower 

 forms, a very complete and active coordi- 

 nation and trophic equilibrium exists, which 

 suffices to superintend the structural differ- 

 entiation and for the maintenance of the 

 body under circumstances where nervous 

 influence as such is excluded. Again, the 

 wandering cells and blood corpuscles, and 

 probably part at least of the chromatophores, 

 are certainly coordinated under vital con- 

 trol, though not under direct or permanent 

 nervous influence. Lastly, the vegetable 

 kingdom furnishes us with structures 

 scarcely less complicated than those of 

 higher animals, but, in spite of the high de- 

 gree of specialization and individuality and 

 the perfection of the correlation of part with 

 part, nothing analogous to a nervous sys- 

 tem has been discovered. Yet in plants 

 there is a remarkable condensation of the 

 characters of the individual in every individ- 

 ual part, in so much that the smallest frag- 

 ment of one of the Bryophyta may reproduce 

 a new individual. These commonplaces of 

 biology are cited to illustrate the fact that the 

 body of a plant or animal may be very com- 

 pletely coordinated, and each part may be 

 stamped in some way with the influence of 

 the whole body without the necessary par- 

 ticipation of the nervous mechanism. 



On the other hand, we have the best of 

 evidence that all nervous action is trophic, 

 and that processes going on in extra-neural 

 tissues are influenced by nerve currents, and 

 that neural equilibrium is also influenced 

 by the somatic- vital processes of cells among 

 which the termini of nervous arborizations 

 ramify. The conclusion is apparently war- 

 ranted that while the nervous system is, in 

 a sense, super-added upon a self-sufiicient 

 somatic equilibrium-sj'stem, and, accord- 

 ingly, the higher nervous processes are, from 

 the stand-point of the body, epiphenomena, 

 yet there is no sharp line of demarkation 

 between them and the somatic forces. 



