382 PHYSIOLOGY, CHEMISTRY AND MORPHOLOGY. 



We may tlius suppose that structural adjustmeuts are formed keep- 

 ing i)ace with the fuudauieutal improvemeut of tbe nervous centers 

 which are working' and dev^elopmg, such adjustmeuts becoming mani- 

 fest as special modifications of the nerves.' 



Besides the basis of a cliemical nature of which I luive spoken, 

 destructive and constructive plienomena owe their reciprocal solidarity 

 to the nervous system, whicli combines with each other the different 

 organs and tissues, and, modifying their respective attitudes, unites 

 them in a homogeneous and stal)le whole. 



Tliat the nervous system presides over destructive functions has 

 long been known. We know, indeed, that almost all the movements 

 of our organism originate from impulses that start from the motor 

 centers and induce modifications of form accompanied by manifesta- 

 tions of energy due to an increase iu the destructive processes in the 

 contractile tissues. Thus when a motor nerve is stimulated it produces 

 in muscle an exaggerated chemical action that leads to a destruction 

 of the contractile tissue. In other terms, a motor nerve is an analytic 

 or catabolic nerve. 



Let us consider now the i)rocesses of inhibition. We have already 

 stated that the fibers of the pneumogastric nerve that supply the 

 heart muscle, have an inhibitory function, and can not for that reason 

 be i)laced in the same category as the motor or catabolic fibers. We 

 will now say, on the other hand, that there are many facts that show 

 that inhibition is the result of an increase in the synthetic processes of 

 organic restoration, and hence relates to a diminution of catabolic 

 acts, a decrease of molecular destruction.^ 



In this way the energy set at liberty by impulses acting on the motor 

 nerves serves to increase the destructive acts in the interior of the tis- 

 sues, and manifests itself externally under the form of motion, heat, 

 electricity, etc. On the contrarj'^, that set in motion by the inhibitory 



' .Janzi, " Les faits et les inductions de I'histologie moderne dans le systeme nerv- 

 eux," Revue exp6riineutale de pathologie mentale et de m6decine legale. 



'^ W. H. Gaskell. " Ucber die elektrisclien Veriinderungeu, welche in dem ruhen- 

 dcn Herzmuskel die Reizung des Nervus vagus begleiteu," Beitriige zur Physiologie. 

 Call Ludwig's Festschrift, Leipzig, 1887, page 114. 



Fano et Fayor. " De (juelques rapports entre les propi'ietes coutractiles et les pro- 

 liri(>t(''8 61ectiiques des oreillettes du cu'ur," Arcliives italienues de biologie, T. IX, 

 page 143, 1888. 



\V. H. Gaskell. '* On the structure, distrilmtion, and function of the nci'ves which 

 innervate the visceral and vascular systems/' .Journal of Physiology, Cambridge, 

 1880, VII, 1. 



Hering, loc. cit. 



J. S. Burdon Sanderson. " Elementary problems in physiology," Report of the 

 British Association for the Advancement of Science, 1889, i)age 604. 



Fano, loc. cit. 



Herzen. " Le rdle psycho-physiologique de Tiuhibition, d'a^jres M. Jules Fano," 

 Revue Scieutiftque, T. XLVI, page 239, 1890. 



P^ano. "Do la chimie respiratoire chez les animaus et chez les jdantes,"' Archives 

 des sciences m^dicales. Vol. XVIII, No. 1, 1894. 



