408 



Dr. C. S. Sherrington. Note on the [May 4, 



returns. Soon after discontinuance of the stimulation the jerk not 

 only returns, but becomes markedly exaggerated. Though abolition 

 or decrease of the jerk is thus temporary, exaltation conversely pro- 

 duced by severance of the hamstring nerve is permanent, lasting at 

 least for some weeks. On the tonicity hypothesis concerning the 

 jerk, exaltation of the jerk by section of the hamstring nerve should 

 be accompanied by a concurrent increase in the tonus of the vasto- 

 crureus muscle. 



It is not easy to judge slight differences in tonus of muscles even 

 where of the fellow muscles of the two sides of the body one normal 

 muscle is available as standard for comparison. Yet any decided 

 difference of tonus must, if multiplied into a sufficient time, amount 

 to a not inconsiderable difference in the chemical condition of the 

 muscle. I have therefore sought to test what influence, if any, section 

 of the hamstring nerve exerts on the extensor muscle of the joint as 

 judged of by the development of rigor mortis in that muscle. 



In muscles paralysed by section of their nerves, onset of post- 

 mortem rigidity is delayed (Kolliker,* Brown-Sequardf). BierfreundJ 

 has found that after semisection of the spinal cord made a few hours 

 before death the onset of rigor in the limbs on the side of section is 

 considerably later than on the opposite side. Inasmuch as depression 

 of tonus is an alteration in the direction of this paralysis, I hoped 

 that time of onset of rigor mortis might serve to indicate whether, 

 cceteris paribus, decrease or increase of tonus had obtained in the muscle 

 for the period immediately preceding death. A few experiments on 

 the influence of nerve section upon speed of onset of rigor mortis gave 

 results accordant with the original by Brown- Sequard and Kolliker. 

 I then turned to the division of, instead of muscular nerves, the 

 anterior roots supplying the muscles. Experiments made on the 

 hind limb of the Cat showed the effect of section of the anterior roots 

 to be a marked delay in the onset of rigor in the muscles supplied by 

 them. The effect was clear, even if the roots were cut only five 

 minutes before killing the animal. I then experimented on division 

 of the posterior roots. The posterior roots of the 6th, 7th, and 8th 

 post-thoracic nerves of one side were severed. In result the ham- 

 string muscles of the corresponding side became rigid later than did 

 those of the opposite side, even in an experiment iu which the animal 

 was killed only a quarter of an hour after section of the" roots. The 

 effect of section of these sensory roots after previous severance of the 

 cord at the 1st lumbar segment was then examined. The severance 

 of the cord, as was to be expected, deferred considerably the onset of 

 rigor mortis in both of the hind limbs. It appeared also to decidedly 



* ' Archiv f. Path. Anatomie,' vol. 10, p. 242, 1856. 



f ' Gaz. Med. de Paris,' No. 42, 1857. 



I ' Pfliiger's Archiv,' vol. 42, p. 195, 1888. 



