December 8, 1916] 



SCIENCE 



809 



tissues, nerve and muscle, than has been 

 thrown by the combined efforts of all other 

 investigators; and the possibilities of future 

 achievement, had he lived, are altogether in- 

 calculable. 



The great majority of his published writings 

 have appeared in the Journal of Physiology 

 and most of them reveal a common trend of 

 thought. Although to appreciate the full 

 meaning of this work and the brilliance of the 

 experimentation one must read his papers, still 

 it is possible to get some idea of his contribu- 

 tion from the Croonian Lecture in which in 

 1912 he summarized the results of his re- 

 searches up to that date. In that lecture 

 entitled " The Process of Excitation in Nerve 

 and Muscle" 1 a comprehensive survey of 

 crucial experiments brings out the broader 

 meaning of his investigations, and shows the 

 essential unity of the apparently diverse as- 

 pects of the subject with which he dealt. 



We owe to him the first clear picture of the 

 sequence of events involved in the phenomena 

 hitherto loosely grouped under the term 

 " excitation." He showed the great importance 

 of the "local excitatory process" which is 

 the immediate consequence of the external 

 stimulus and which must be clearly distin- 

 guished from the " propagated disturbance " 

 to which, if sufficiently intense, it gives rise. 

 By a careful quantitative study of the " sum- 

 mation of inadequate stimuli " and of the time 

 factor in the exciting electric current he laid 

 the foundation for the completion of ISTernst's 

 hypothesis of excitation by Hill and for his 

 own quantitative verification of the hypothesis 

 in its modified form. With his characteristic 

 modesty and sense of the limitations of our 

 knowledge he claims for this verification only 

 a " guide to the strengthening of our experi- 

 mental data " ; but to one less conversant than 

 he was with the difficulties in the way of draw- 

 ing final conclusions, it would seem that he 

 had presented an excellent case for the con- 

 clusion that the local excitatory process is a 

 concentration of ions at some point within the 

 tissue. 



In his more recent researches his attention 



i Proc. Boy. Soc, Vol. 85, B, p. 495. 



has been given less to the nature of the local 

 excitatory process and more to the properties 

 of the " propagated disturbance " which re- 

 sults only when the former process reaches 

 adequate intensity, and which is manifested 

 by the electrical response and the refractory 

 phase. Among these later papers is one which 

 seems to me his most characteristic and bril- 

 liant work, the elucidation of the " apparent 

 inhibition " of Wedensky. 2 The way in which 

 this baffling phenomenon is dissected and ex- 

 plained step by step by means of exquisite 

 and crucial experiments makes it the most per- 

 fect piece of scientific work I know of. Every 

 experiment is so designed as to be crucial, to 

 give unequivocally the answer to the question 

 at hand; and the clarity with which difficult 

 and complex ideas are expressed reveals an 

 extraordinary gift of exposition. 



In experimentation it was his most salient 

 trait to devote his energies wholly to what 

 really counted in yielding the result. He made 

 most of his apparatus with his own hands, and 

 he never wasted a minute trying to make it 

 look neat; perfect working was the sole aim. 

 To furnish uniform motion of his photographic 

 plate a discarded motor-bicycle cylinder was 

 filled with oil and a hole drilled in the piston- 

 head through which the escaping of the oil 

 regulated the speed with an accuracy which 

 sufficed for the most refined quantitative deter- 

 minations. A sense of proportion character- 

 ized all his work. He never wasted effort in 

 securing refinement and accuracy in one part 

 of an experiment which would be nullified by 

 unavoidable errors in another. 



The fruits of his work are not measured 

 merely by his own published writings, for 

 Adrian, trained by him in thought and in ex- 

 perimental technique, has followed out some 

 of the ideas suggested by his researches with 

 consummate success. Thus he has established 

 the " all-or-none " law for the nerve impulse ; 

 and the far-reaching consequences in physiol- 

 ogy of this achievement are expressed in a 

 letter by Professor Sherrington: 



All or nothing as a principle of nerve-fiber re- 

 sponse seems to me as to you established. It must 



2 Jour. Physiol., Vol. 43, p. 46. 



