QUARTERLY JOURNAL 

 OF EXPERIMENTAL PHYSIOLOGY 



ON THE TIME TAKEN IN TRANSMISSION OF REFLEX IM- 

 PULSES IN THE SPINAL CORD OF THE FROG. By 

 Florence Buchanan. (From the University Museum, Oxford.) 



CONTENTS. 



PAGE 



I. Introduction — 



General method, and preliminary experiments on excised nerve-muscle 



l^reparatious ........ 1 



II. The Same-Limb Reflex Time in the Normal Cord — 



Methods of preparation and of recording, and of recognising the reflex 



effect in the records. Interpretation of the records ... 5 



Results, estimation of time to be deducted for transmission in nerve. 

 Inquiry as to the efifects of alteration in strength of stimulus, tempera- 

 ture, fatigue . . . . . . . . 10 



III. The Same-Limb Reflex Time in the Strychnine Cord — 



The influence of the drug on the reflex efi'ect and on the reflex time. 

 Inquiry as to eftects of alteration of strength of stimulus, temperature, 

 fatigue on synapse time . . . . . . . 18 



IV. The Same-Limb Reflex Time in the Phenol Cord ... 29 



V. The Crossed Reflex Time in the Normal, the Strychnine, and the 



Phenol Cord — 

 The difliculty in obtaining the true reflex efi^ect in a normal cord. The 



extra delay in the stryclinine cord and inquiry as to the influence upon 



it of strength of stimulus (proximate and ultimate) and of temperature 30 



Significance of results, difl^erentiation of synapses and the relative actions 



of drugs and of fatigue upon them ..... 55 



Discussion as to the significance for normal cords of results obtained ^nth 



strychnine and phenol cords ...... 58 



VI. Concluding Remarks ....... 63 



VII. Summary ......... 64 



VIII. Explanation of Figures ....... 66 



I. Introduction. 



The estimate which seems to be generally accepted ^ of the reduced reflex 

 time in the lower part of the frog's spinal cord in a reflex contraction 

 of the simplest kind is that which was formed by Wundt in 1876,- after 

 making experiments in which the mechanical responses of a gastrocnemius 



» See article on "Nerve Cell" in Schiifer's Text Book of Physiology, 1900, 

 vol. ii., p. 609. 



■•^ W\indt, Unters. z. Mechanik d. Nerven u. Nervencentren, Abth. II. : " Ueber d. Re- 

 flexvorgang u. d. Wesen der centralen Innervation," Stuttgart, 1876. 



VOL. I. — JAN. 1908. 1 



