When the worm was divided not exactly at the middle, it 

 would be the head piece, or the tail, according to their 

 size, that first ceased to exhibit signs of vitality ; and in 

 poisoning the entire worm by touching it, for instance, 

 with solid citric acid, (which first excites violent action, 

 but quickly destroys mobility altogether,) no difference 

 was noticed in the time in which that result arrived, by 

 applying the poisonous agent to various parts of the ani- 

 mal ; all showing that there can be no essential difference 

 in the different ganglia, as reservoirs of life, and that one 

 confers no more vitality on the whole, or sensibility on 

 the parts, than another. On making similar experiments 

 on insects, dividing them at the juncture of the corslet 

 with the abdomen, the life of the disconnected pieces, as 

 of those of the worm, remained inherent in them for 

 hours, sometimes for days ; different insects however dif- 

 fering in the period of final extinction. In some instances 

 perhaps, the portion to which the head was attached 

 might have appeared to be endowed with a somewhat 

 more enduring vitality, and might have exhibited some 

 feeble indication of life, after the other extremity had al- 

 ready ceased to move ; but, the difference was trifling, 

 (and one should take in the fact that the upper ganglion is 

 generally the larcjest in size, as perhaps sufficient to ac- 

 count for it), nor was the result invariable. Of a Slaps 

 mucronata, for instance, which I had divided in the 

 manner specified, the head and corslet, with their append- 

 ages, ceased to give signs of vitality long before the rest of 

 the beetle had ceased to move. Again, the head cut 

 off from a fly, or any other insect, soon dies, the body 

 still surviving for some time ; so that the head would seem 

 more dependent on the body, than the body on the head. 

 At any rate, the considerable period during which either 

 part of a divided insect continues to manifest signs of life, 

 leads to the inevitable conclusion of their not drawing sup- 

 plies from the head, and of, in fact, their entire indepen- 



