267 



The Action of Anaesthetics on Living Tissues. Part I. — The 

 Action on Isolated Nerve. 

 By N. H. Alcock, M.D. 



(From the Physiological Laboratories of the University of London and St. Mary's 

 Hospital Medical School.) 



(Communicated by A. D. Waller, F.E.S. Eeceived November 9, — 

 Eead December 14, 1905.) 



CONTENTS. 



PAGE 



I. Introduction 267 



II. Experiments. — Series I. Anaesthetic to Whole Nerve 267 



III. Series II. — CHC1 3 to Parts of Nerve in varying Percentages 269 



IV. Series III.— Fixed Percentages, CHC1 3 and Ether 271 



V. Series IV. — Simultaneous Anaesthetic " Balance " Experiments 273 



VI. Series V. — Electrical Eesistance of Nerve after CHC1 3 , and Control 



Experiments 275 



VII. Series VI. — Electrical Resistance of Nerve after Ether 278 



VIII. Observations 280 



Introduction. 



The action of anaesthetics on isolated nerve has already been studied by 

 Waller* as regards the effect on the negative variation in the sciatic of the 

 frog, and by myself in mammalian nerves.f In the course of these 

 researches it became evident that the anaesthetics used (chloroform, ether, 

 carbon dioxide) affected not only the negative variation, but also the injury 

 current, and as this action has not been studied before, as far as I am 

 aware, it seemed desirable to investigate the matter not only in nerve, but 

 also in other tissues. 



The inquiry falls naturally under two heads: first, in how far the 

 phenomena throw light on the processes of nerve action ; and, secondly, as 

 regards the chemical and physical action of anaesthetics on the animal 

 protoplasm generally. These are obviously only parts of the same story, 

 but for convenience I have considered the subject mainly under the first 

 heading in this part, leaving the more general question to a future occasion. 



Experiments. 



If the sciatic nerve of a frog be taken and a fresh transverse section be 

 made at the distal end, and this end be placed in contact with one non- 



* Waller, "Lectures on Animal Electricity," 1897, and ' Proc. Physiol. Soc.,' 

 November 13, 1897, etc. 

 t ' Roy. Soc. Proc.,' vol. 71, p. 264, and vol, 73, p. 166. 



VOL. LXXVII. — B. U 



