Transmission-time of Reflexes in Spinal Cord of Frog 1!> 



In most, therefore, the response with the nerve intact, whether electrical 

 or mechanical, was not much longer than when, after dividing it, its 

 peripheral end was stimulated. A few, however, were made when the pre- 

 paration was in the attitude characteristic of strychnine poisoning, or 

 only just beginning to recover from it. 



The conditions obtaining, and the results yielded in the several responses 

 in nineteen tj'pical experiments, have been tabulated in the same way as 

 were those for normal cords. Certain of the conditions, and the results 

 obtained in thirteen of them, will be found on the left-hand side (first six 

 columns) of the tables beginning on p. 35. In almost every case in which 

 the animal was only lightly drugged, the mechanical, as well as the 

 electrical response was recorded, in order that its strength and duration 

 might be compared with those of the twitch (einfache Zuckung) which was 

 recorded at the end of the experiment. 



It was only in three experiments that the cord delay was through- 

 out of longer duration than appears to be characteristic of good normal 

 cords under similar conditions. The majority of the experiments do not 

 therefore confirm the conclusion which Wundt came to from his obser- 

 vations on the mechanical reflex response of the strychnised animal, 

 that, namely, the efi'ect of strychnine on the cord is to lengthen the delay 

 The three preparations in which the cord delay, after deduction for 

 transmission time in nerve in the same way as before, was found to be 

 throughout 24cr or more, were the only ones in which not only were the 

 arms flexed, but the legs were rigidly extended when the preparation was 

 made. The reflex electrical responses in all three were serial. Verworn^ 

 has shown that in acute stages of strychnine poisoning not only the central 

 nervous system but the heart also is affected by the drug. I have there- 

 fore examined the heart at the end of these and other experiments. In 

 one of the three [Exp. 50], made on a specimen which had been in the 

 attitude characteristic of strychnine poisoning for about two hours, and 

 in which the buccal respiratory movements had already ceased, the heart 

 was hardly beating at all, the blood was very blue, and tlie preparation 

 seemed to be nearly asphyxiated ; both the direct and the reflex electrical 

 eflfects were very feeble (rise of curve ver}^ gradual) ; the probable cord delay 

 was between 25cr and 30o- in four of the responses ; it was as much as o9a 

 in the first one, and 41o- in the second. Of the other two preparations, the 

 one had been in the attitude characteristic of strychnine poisoning for half 

 an hour only, while the other had been in it for several hours. In both, 

 the buccal respiratory movements were laboured. The heart was beating 

 feebly. The reflex effect was not as strong as the direct effect : and in 

 most, but not all, of tlie responses, it did not become maximal until some 

 (J-10(T after its commencement ; sometimes, in the second of the two experi- 

 ments (in which the stimuli to the nerve were kept close to the threshold 

 value in strength) [Exp. 55], not imtil 20o- after. Fig. 10, A (see p. 52) 

 ' Verworn, Archiv f. (Anat. u.) Physiol., 1900, p. 385. 



