254 ' Waller 



place of the normal i ^gth for the second cell (or synapse) nearly y^o^hs. 

 It is on account of this and similar observations that I have not said above 

 " exclusively," but only " principally." 



The difference between (1) the direct and (3) the reflex contraction on 

 the same side gives 0"008 as the value of the corrected reflex time. 



The coincidence of connnencement of response to (2) excitation of the 

 upper part of the spinal cord and to (3) cutaneous excitation on the same 

 side indicates that in both cases the mechanism of the delay is very probably 

 of similar character. The longitudinal transmission delay of 0*008, like the 

 corrected reflex time of 0*008, is probably occasioned by one similar nerve 

 station. Lost time in nerve-fibres, at, say, 30 to 50 metres velocity per 

 second, is in this connection negligible. 



Fig. 2. — After stiychnine. 

 (About 0-1 milligi-amme injected.) 



(1) Direct muscular contraction, 0*010 sec. 



(2) Spinal muscular contraction, 0-020 „ 



(3) Keflex muscular contraction, 0-056 ,, 



The identical values of the lost times in the two cases (2) and (3), in 

 which the cell station at the origin of motor fibre is aroused by a cord fibre (2) 

 and by a skin fibre (3) respectively, so that the commencements of the two 

 contractions normally coincide, are altered in consequence of the action of 

 strychnine. The delay of (2) is very slightly increased ; that of (3) is very 

 considerably increased. The augmentation of (2), as of (1) the direct 

 muscular contraction, was so small, 0010 as compared with 0-008, as to be 

 within the limits of experimental error ; but the augmentation of (3) the 

 reflex time, by no le.ss than 0*040 sec, w^as clear and unmistakable : it is a 

 measure of the delay suffered by the centripetal stimulus at the junction 

 between afferent nerve and spinal cord. 



Miss Buchanan used much lighter doses of strychnine than I did, viz. : 

 1 min. of 0-01 per 100 liq. strych. to 2 mins. of 0*02 per 100 liq. strych., 

 while I used 2 mins. of 1 per 1200 liq. strych. 



