RESPIRATORY MOVEMENTS OF INSECTS. 
145 
the rate of forty-eight. It was laid on the table, and in ten minutes it ceased to 
respire. In the other segments the breathing went on languidly, and soon ceased 
entirely. 
The foregoing experiments, on the effects of dividing the abdomen of the insect, 
are confirmed in their evidence of the several ganglia being the centres, each in its 
own segment, of the respiratory, as well as of other involuntary movements, by some 
that show the influence of chloroform and ether. 
Having ascertained that the complete immersion of insects in the vapour of chlo- 
roform or sulphuric ether quickly suspends the power of voluntary, and then of the 
respiratory and other involuntary movements, I wished to learn the influence of 
these liquids applied in a more limited manner. 
Exp. xviii. — In a dragon-fly {Libellula vulgata), which was respiring vigorously, 
I completely suspended the respiratory movements by moistening the under surface 
of the abdomen with a camel’s-hair brush dipped in chloroform. The insect remained 
quite lively; and though so much of its respiratory movement was thus checked, yet 
no difference could be observed in the strength or activity of its voluntary actions. 
In another, I suspended the abdominal respiratory movements by a similar applica- 
tion of chloroform, but it was so little affected in its general motor power that it 
took flight on being released from the hand. 
In another, I suspended the respiratory motion of the two upper segments of the 
abdomen, by applying chloroform to them alone. The other segments remained in 
action, till, by similarly moistening them, segment after segment, I gradually stayed 
the action of them all. 
These effects were not due to the tracheae being filled with liquid. None like 
them were produced by immersing dragon-flies in water; for in this liquid the respi- 
ratory movements continue vigorous, and are accelerated when the water is of high 
temperature. On the other hand, the same suspension of respiratory motion ensues 
when only the vapour of chloroform is locally applied. I put about five drops of 
chloroform into a glass bottle, and tied a piece of white leather tightly over it ; and 
then, through a small hole in the leather, I passed only the abdomen of the insect 
into the bottle. When, in a minute, I withdrew it, the respiratory movements had 
altogether ceased ; but the insect remained conscious, and could be readily excited, 
presenting then the curious spectacle of the legs and wings quickly moving, while 
not a breathing movement could be seen. In a few minutes very slight respiratory 
actions became visible ; and they were gradually restored to nearly their former rate 
and power. I then repeated the experiment, with the same result. 
It might be certainly anticipated, from these experiments, that destruction of all 
the ganglia would abolish all respiratory movements ; but it seemed right to deter- 
mine the point by experiment. 
Exp. xix. — I decapitated a dragon-fly {Libellula vulgata)-, there were still vigorous 
respiratory movements, thirty in the minute ; and the most lively reflex actions were 
