148 MR. W. F. BARLOW ON THE RESPIRATORY MOVEMENTS OF INSECTS. 
independent of the rest : they may be performed in separate segments, provided their 
nervous ganglia and cords are entire, and not paralysed by such influence as that of 
chloroform or ether. 
4. The removal of the head, including the supra- and sub- oesophageal ganglia, does 
not, like the removal of the medulla oblongata of the vertebrate animal, put a stop to 
the respiratory movements, but diminishes their frequency and force, and deprives 
them of all influence of the will and of mental emotions. 
5. The shock inflicted in the sudden destruction of the head, or of the terminal 
part of the abdomen, generally stops all the respiratory movements for a time, and 
greatly enfeebles them during the remainder of the insect’s life. 
6. The general tendency of the observations is to corroborate the opinion of the 
self-sufficiency of the several ganglia for the movements of their appropriate seg- 
ments, and, thus far, of their essential independence; at the same time, their mutual 
relation and influence are proved by the co-ordinate similar movements of the seg- 
ments, and by the diffused influence of shocks. 
