INTERFERENCE OF EXCITATIONS 



227 



Gottingen laboratory as well as that of Bonn^ 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 



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 Ruckenmark." Zentralblatt f. 

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

 stadium und die Hemmungsvorgange im Ruckenmark des Strychninfrosches." Zeitschr. 

 f. allgem. Physiologie Bd. X, 1910. Julius Vessi: "Der einfachste Reflexbogen im 

 Ruckenmark." Zeitschr. f. allgem. Physiologie Bd. XI, 1910. Oinuma: "Ueber die 

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

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



