168 SCIENCE PROGRESS. 



coming into effect, will cause single muscular twitches, and 

 if during a rhythmic series of such twitches the original 

 tetanising current is remade, the twitches are temporarily 

 inhibited just as if the twitching muscle were a contracting 

 ventricle and the sciatic nerve its inhibitory nerve. The 

 experimental fact is clear and elegant, but does not bear 

 the conclusion that would no doubt be placed upon it by 

 special seekers for musculo-inhibitory nerves. Moreover, 

 it has not been cleared of a possible fallacy that was 

 found to be subversive of the somewhat similar experi- 

 ments of Valentin and of Grunhagen. 



If the idea of inhibition and of inhibitory nerves is not 

 to become entirely dissipated, if we are to admit under 

 that rubric the mere passive cessation of action as well as 

 the active arrest of action, then all nerves are inhibitory, 

 all paralysis is inhibition. And to any one convinced of the 

 existence of efferent inhibitory nerves to skeletal as well as 

 to vascular muscle it is no drawback that we do not know 

 whether the cardiac vagus acts directly on the muscle or 

 through the intermediation of ganglion cells, that we do 

 know that all inhibitory phenomena effected through afferent 

 fibres have their seat of consummation in nerve-centres, 

 that the experimental demonstration of musculo-inhibitory 

 nerves is most inconclusive of their existence. And it is 

 possible to go further in the construction of suppositions, to 

 suppose that not only muscle but all living tissues are under 

 the control of direct inhibitory as well as of motor nerves, 

 that inhibitory nerves are inhibitory because anabolic, motor 

 nerves motor because katabolic. But the superstructure in 

 its present state needs to be buttressed and underpinned 

 by more cogent experimental facts than any that have 

 recently been employed for the purpose. The case for the 

 inhibitory nerves of skeletal muscle is unproven. 



BIBLIOGRAPHY. 



BlEDERMANN. Ueber Hemmungserscheinungen bei electrischer 

 Reizung quergestreifter Muskeln. Wiener Sitzungsbericiite, 

 1885 ; also in Pfliigers Arch., vol. xlvii., p. 243, 1890. 



