INTERFERENCE OF EXCITATIONS 



227 



Gottingen laboratory as well as that of Bonn 1 we have come to 

 look upon the reflex arc in the spinal cord as consisting of the 

 following elements : a neurone in the spinal ganglion, a neurone 

 in the posterior horn and a motor neurone in the anterior horn. 

 This is the most direct route between the point of stimulation 

 and that of the responding organ of a unilateral reflex. (Figure 

 60.) It is known that the excitation becomes weaker in passing 



AS 



o 



Fig. 60. 

 Scheme of the simplest unilateral reflex arc of the spinal cord. 



from the entrance of the excitation into the spinal cord to the 

 motor elements of a lower level on the same side or to those on 

 the opposite side. In order to obtain a response a stronger stimu- 



1 Max Verworn : "Die einfachsten Reflexwege im Riickenmark." Zentralblatt f. 

 Physiologic Bd. XXIII. Tiedemann: "Untersuchungen iiber das absolute Refractar- 

 stadium und die Hemmungsvorgange im Riickenmark des Strychninfrosch.es." Zeitschr. 

 f. allgem. Physiologic Bd. X, 1910. Julius Veszi: "Der einfachste Reflexbogen im 

 Riickenmark." Zeitschr. f. allgem. Physiologic Bd. XI, 1910. Oinuma: "Ueber die 

 asphyktische Lahmung des Ruckenmarks strychninisierter Frosche." Zeitschr. f. 

 allgem. Physiol. Bd. XII, 1911. Satake: Not yet published. 



