POISONS. pA 
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 conducted 
a research upon ‘comparative toxicology,” in which he has de- 
voted the larger share of his attention to the Meduse. While 
expressing my gratification that when he adopted my methods he 
succeeded in 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 that 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 which does not ensue when the tissue is stimulated 
mechanically, he regards the fact as proof that the muscular 
tissue remains unaffected while the nervous 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 nerve 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 mean the induction shock. The remarkable transposition 
of Dr. Krukenberg’s ideas upon this matter does not affect the 
results of his observations upon the action of the various poisons ; 
it only renders fatuous his criticism 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 elements alone remaining uninjured, from the bare 
