December 1898] RUDIMENTARY NERVOUS SYSTEM 385 



probably traversed by some wave-currents endowed with a 

 celerity that gives them, in some measure, the means to oppose 

 themselves to the currents coming from the ganglia of the sym- 

 pathetic system as well as to those issuing from the viscera. Some 

 disordered movements of the heart, intestines, etc., are naturally the 

 result of the suppression of the action of the brain and medulla. 

 This theory ought to be applied in cases of vascular inhibitions. 



(g) On the part performed by the medulla. — " Les resultats 

 contradictories de plusieurs physiologistes au sujet de la fonction des 

 cordons anterieurs et lateraux de la moelle, tenaient aux modes 

 divers d'excitation mis en usage. Vulpian a constate qu'il faut une 

 excitation tres energique pour determiner les contractions dans les 

 muscles recevant leur innervation des parties situees au dessous du 

 faisceau excite : que les attouchements, les piqures, les grattages 

 superficiels ne produisent aucun resultat, mais qu'on met en jeu 

 I'excitabilite de ces faisceau x en les pressant entre les mors d'une 

 pince." 1 That is, until a powerful wave is produced. It is just the 

 same with large masses of mercury, the vibrations of which cannot 

 be brought about by rubbing them with a soft feather, and much 

 less when the latter is protected by a cover. 



" La substance grise de la moelle ne conduit point les impressions 

 sensitives par des voies anatomiquement preetablies, mais pour ainsi 

 dire d'une maniere indifferente. Les sections transversales peuvent 

 diviser la moelle epiniere dans une grande partie de leur epaisseur, 

 et dans un sens quelconque, sans interrompre la transmission des 

 impressions sensitives, a la condition qu'une petite partie de la 

 substance grise (une sorte de pont) ait ete respectee" par l'incision. 

 L'animal conserve la possibility de reconnaitre le point du corps 

 irrite. Vulpian parlait d'une sorte d'empreinte originelle des 

 sensations. . . ." The question is quite a simple one. The differ- 

 ences are only in the intensity of the vibration occasioned by the 

 variability of distance, degree of excitation, point on which it worked, 

 protecting envelopes, etc., and as a matter of course the excitations 

 are conveyed almost in the same manner and each of them reaches 

 certain points of the sensorium, however small the bridge of the 

 gray substance may be. 



Make a sort of a medulla with mercury and insert some con- 

 ductors on its surface. (Fig. 10.) Some multipolar cells and con- 

 ductory threads are then to be disposed in its upper part, as in 

 Luy's methods. A stronger excitation will then rise higher than a 

 weaker one and the elements placed at different heights will be 

 diversely effected. Each of these reacts on the motor threads, but 

 only in case it be sufficiently excited. (Fig. 10.) In this manner 

 the perception of simultaneous sensations and multiple reactions 



1 Kitss ami Duval, I.e., p. 67. 



