POISONS. 237 



away, and finally the medusa returns to its normal 

 state.* 



* Since the above results on the effects of poisons were pub- 

 lished in my Royal Society papers, Dr. Krukenberg has couducted 

 a research upon " comparative toxicology," in which he has de- 

 voted the larger share of his attention to the Medusae. While 

 expressing my gratification that when he adopted my methods he 

 succeeded iu confirming my results, I may observe that the 

 criticism which he somewhat bluntly passes upon the latter is not 

 merely unwarranted, but based upon a strange misconception of 

 a well-known principle in the physiology of nerves and muscles. 

 This criticism is tliat these results as published by me are 

 worthless and *'a dead chapter in science," because I failed to 

 prove that it was the nervous (as distinguished from the muscular) 

 elements which were effected by the various poisons. In his 

 opinion this distinction can only be made good by employing 

 electrical stimulation upon the sub-umbrella tissue when this has 

 lost its spontaneity under the influence of poisons : if a response 

 ensues wliich does not ensue when the tissue is stimulated 

 mechanically, he regards the fact as proof that the muscular 

 tissue remains unaffected while the nervuus tissue has been 

 rendered functionless. 



Now, in the first place, I have here to show that there is, as I 

 have said, a fundamental error touching a well-known principle of 

 physiology. So far as there is any difference between the ex- 

 citability of nei"ve and muscle with respect to mechanical and 

 electrical stimulation, it is the precise converse of that which Dr. 

 Krukenberg supposes ; it is not muscle, but nerve, which is the 

 more sensitive to electrical stimulation — by which I understand 

 him to moan the induction shock. The remarkable transposition 

 of Dr. Krukenberg's ideas upon this matter does not affect the 

 results of his observations upon tlie action of the various poisons; 

 it only renders fatuous his criticisai of these same results as 

 previously published by me. 



In the next place, I have to observe that in all my experiments 

 I tried, as he subsequently tried, both kinds of stimulation, and 

 also the constant current; but I soon found that even when one 

 went to work with one's ideas upon the subject in a non-inverted 

 position, no trustworthy inference could be drawn in favour of 

 the muscular clcaicuts alone remaining uninjured from the bare 



