54 



Buchanan 



take effect, and in which the (^rossed-retlex response was coming into 

 existence under our eyes, as it were. Thus, in Exps. 42, 47, and 48, the hrst 

 time it could be obtained it was only to a much stronger stimulus than 

 such as afterwards sufficed to produce it. In two of these [Nos. 42 and 48] 

 the extra cord delay was longer in the first response recorded than it was 

 subsequently, the stimulus, although stronger, being nearer to the threshold 

 value than weaker ones were later. This seems to me to be the best piece 

 of evidence we have at present that strength of stimulus, when near its 



Fig. 11. — Electrical responses of the gastrocnemius of a frog which had been 

 injected the day before with 2 minims 0-02 percent, liquor strychnise, and 

 which was in the attitude characteristic of strychnine poisoning when it was 

 prepared (Exp. 55). 



A ami C, first and eighth responses respectively obtained when the intact sciatic nerve 

 of the same side was excited. [Time lines 840 and 770 per cent, respectively.] B and 

 D, first and tenth responses respectively obtained when the sciatic nerve of the 

 opposite side was excited. (Time lines 830 and 820 per second respectively.] 



threshold value, is likely, in the normal animal, to affect synapse time, since 



the cords in these two experiments were in less abnormal condition than 



was that used in Exp. 55.^ 



The effect of altering the temperature of the cord on the extra cord 



^ Since this paper was first prepared for the press I have made a good many more 

 experiments in which the strengtli of the stimulus was altered. The results amply confirm 

 the conclusion already come to, namely, that, increasing the strength of the stimulus when 

 once its value is above a certain amount does not shorten the time taken to pass indi- 

 vidual synapses, although it may increase the number crossed abreast. They will be dealt 

 with in a future communication, together with the results obtained in more co'mplex reflexes 

 in which cord delay, and possibly the number of synapses crossed in series, appears to be 

 less constant in any one preparation than it is in the two which are here considered. 



