Transmission-time of Reflexes in Spinal Cord of Frog 49 



be obtained. In all four experiments the crossed-reflex effect never became 

 strong, though in the first two the same-side reflex effect was no stronger. 

 In all these preparations, in which the first appearance, as it were, of a 

 crossed-reflex effect in response to a single instantaneous stimulus was 

 observed, the extra cord delay in the case of the crossed reflex was very 

 nearly the same as, sometimes somewhat longer than, the whole cord delay 

 in the case of the corresponding same-side reflex. In two out of the four 

 [Exps. 4, 42] it was longer the first time the effect appeared than it was 

 in any of the subsequent responses, and this notwithstanding the fact that 

 in all of them stronger stimuli were used (and had been obliged to be used) 

 to get the effect at all at the beginning. 



In one other experiment [No. 53], made on a preparation which had, so 

 far as external appearance went, completel}'^ recovered from the effects of a 



Fig. 6. — Electrical responses of the gastrocnemius of a 

 large frog which had been injected the day before 

 with 2 minims 0*02 per cent, liquor strychniae, and 

 had apparently quite recovered (Exp. 53). 



A, sixth response obtained when the intact sciatic nerve of the 

 same side was ex ited. [Time lines 810 per second.] 

 B, eighth resiimse ol.iiinLMl when the sciatic nerve of 

 tlie opposite side was excited. (Time lines 815 per 

 second.] 



dose of strychnine so small (in proportion to the size of the frog) that these 

 had never been marked, the extra reflex delay in the one case was about 

 equal to the whole delay in the other. Although it could be obtained the 

 first time the sciatic of the oppo.site side was excited, the crossed-reflex 

 effect was extremely feeble, and in this case it remained so throughout the 

 experiment. It was strongest the eighth and last time it was recorded; 

 but fig. 6, B, shows how weak it was even then. The same-side reflex 

 responses in this experiment, on the other hand, the record of the sixth of 

 which (taken immediately after that of the eighth crossed reflex) is repro- 

 duced, had been throughout about as strong as the direct effect (which was 

 again double in all the records taken of it). There was a corresponding 

 diflference in the strength of the mechanical responses. 



The cord delay in the crossed reflex was about double what it was in 

 the simpler reflex in two other preparations [Nos. 40 and 55], both of which 

 were well strychnised, and in both of which the reflex response could be 

 produced as readily, i.e. at the start, and to a stimulus of the same strength 



VOL. I. — JAN. 1908. 4 



