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Post-tetanic Tremor. (Supplementary Note. ) 
By Davin Fraser Harris, M.D., B.Sc. (London).* _ 
Since the publication of my paper on this subject,f my attention has been 
called to the fact that the phenomenon has been previously noticed by 
Dr. Sydney Ringer.} 
I regret that I was unacquainted with his paper until after mine had been 
published. Dr. Ringer states :—“This powerful prolonged faradisation, for 
one or two minutes, of the sciatic nerve of a cut-off leg of an undrugged 
frog, causes the lhmb to remain extended, and if it be held vertically, foot 
upwards, it falls more slowly than happens after only a momentary stimula- 
tion”; and again: “These fibrillary twitchings and this spastic condition 
can be produced in normal imprisoned muscle.” There can be no doubt that. 
what Dr. Ringer called “fibrillary twitchings” and I have termed “ post- 
tetanic tremor ” are identical phenomena. | 
In connection with the tremor which occurs in the muscles of the lobster 
during faradic stimulation, I ought also to have alluded to Professor 
C. Richet’s discovery§ of an identical tremor (“tetanos rythmique”) in the pincer 
muscle of the crayfish, but I was unable to obtain a copy of his paper until 
after my own had gone to press. 
[* This supplementary note was received March 11, 1908.—Sec. R.S. ] 
+ © Roy. Soc: Proc., iB; vel) 80) p:737, 1908: 
+ “Report on the Influence of Rhombic Sodium-phosphate and Sodium-bicarbonate on 
Muscular Contraction,” ‘ Brit. Med. Journ., July 19, 1884, vol. 2, p. 114. 
§ “Contribution 4 la Physiologie des Centres Nerveux et des Muscles de l’Ecrevisse,” 
‘Arch. de Physiologie Norm. et Path., fig. 22, p. 563, vol. 6, 1879. 
