Transmission-time of Reflexes in Spinal Cord of Frog 



51 



sixth responses as short as 6cr. The records of these two responses show — 

 but it is much more evident in that of the sixth than in that of the fifth 

 (the one reproduced) — that the central stimulus was not exerting its full 

 strength at the start. Three of the crossed-reflex responses, and two of 

 those of the same side, show, as those of no other preparation in so early 

 a stage of strychnine poisoning do, that a second stimulus of central 

 origin was affecting the muscle some 50-40(t later than the first began to 

 aflfect it. This indicates that the drug was taking effect rapidly. In two 

 of the responses in another preparation [Exp. 49] the extra delay became 

 as short as da- ', but this is hardly so short as to be called exceptional as 



Fig. 8. — Electrical nsponses of the second gastro- 

 cnemius of a frog which, after records had 

 been taken with the other gastrocnemius, 

 before the injection of strychnine, was then 

 injected with 5 minims 0"005 per cent, 

 liquor strychnise (Exp. 45). 



A and C, first and fourth responses obtained when the 

 intact sciatic nerve of the same side whs excited. B 

 and D, first and fifth responses obtained when the 

 sciatic nerve of the opposite side was excited. 

 [Time lines 840 per second in all four.] 



compared with the whole delay in the same-side reflex, which was once in 

 one strychnine preparation (Exp. 14, see p. 21) equally short. 



The extra cord delay in all three preparations [Nos. 50, 52, 55], which 

 were in the attitude characteristic of strychnine poisoning when the records 

 were taken, and in which the heart as well as the cord was aflected by the 

 drug, was long, although it was only in Exp. 55 that it was as long as the 

 whole same-side reflex time. With all these preparations the crossed-reflex 

 effect was stronger at the beginning in some of the responses than the 

 same-side reflex eflect. This may be seen, for instance, by comparison of 

 the records of the two kinds of response in Exp. 52, reproduced in fig. 10. 

 In Exp. 50, which is not introduced into the table, the extra delays in 

 responses recorded alternately with the same-side responses referred to on 

 p. 19, were, in order, 85cr, 20o-, 19cr, 14(r. 



