28 



Buchana 



Exp. 42. Nov. 15, 1906. Room temp. 15° C. One minim 0-01 per cent. liq. 

 strych. injected one hour before making the preparation. 



Induction current 

 to nerve. 



Strength. 



10,000 

 10,000 

 5,000 

 10,000 

 10,000 

 10,000 



Length, in millimetres, of 



muscle 

 from en- 

 trance of 

 nerve to^. 



nerve 

 from Cu 

 electrode 

 to muscle. 



nerve 

 from Cm 

 electrode 

 to cord. 



Time, in thousandths of a second (a), 



taken by 



impulse to 



reach p 



directly 



(measured). 



4-2 



4-2 



4 



4-2 



4-2 



interval 

 between 

 arrivals of 

 direct and 

 of reflex 

 effects at p 

 (measured). 



13-2 

 14-4 



no reflex 

 14-4 

 13-2 

 12-1 



to be de- 

 ducted 

 for trans- 

 mission 

 in nerve 

 (assumed). 



2-3 

 2-3 



effect 

 2-3 

 2-3 

 2-3 



Probable 



delay in 



cord. 



10-9 

 12-1 



12-1 



10-9 



9-8 



Bag of ice then put on the back of preparation for five minutes. 



10,000 I d 10 14 I 35 j 4-2 23 2-3 217 



10,000 d 10 14 35 4-2 24 2-3 22-7 



10,000 d 10 14 35 I 4-2 20-7 2-3 18-4 



5,000 d 10 14 I 35 I 4-2 22-2 2-3 19-9 



10,000 d 10 i 14 35 , 4-2 21 2-3 18-7 



Ice-bag removed. A second minute dose of strychnine given at tlie same 

 time (in the hope of securing responses to the excitation of the other 

 sciatic also), which fact may (though I do not think it does) detract 

 from the value of the results obtained from the records taken five 

 minutes later. 



10-8 

 12 

 12 

 12-1 

 11-1 

 9-7 



It is also shown in Exp. 48, of which the data, when the whole prepara- 

 tion was at room temperature, have already appeared in tabular form on 

 p. 13, and of which most of the data, after the back had been cooled, 

 appear on the left-hand side in the table p. 41. 



A number of experiments I made some years ago for another purpose, 

 and in which the reflex eflfect was produced by excitation of the skin, not 

 of nerve, show the same sort of thing. To these I shall have to refer in 

 another connection on another occasion. What is very striking in the two 

 recent experiments is that in the one case [Exp. 42] the cord delay is 

 almost exactly doubled by cold, in the other [Exp. 48] almost exactly trebled. 

 But whether any significance should be attached to these facts the evidence 

 is not as yet great enough to decide. The further question suggests itself 

 as to whether the influence of cold is a direct one on the cells (or the 



