Royal Society. 229 



suspended horizontally and the knob of a Leyden jar is carefully 

 brought near it, at a certain distance from the knob the pointed 

 end is strongly repelled, while the blunt end is attracted." 



We may add to these remarks, that in some cases we have 

 succeeded in causing a bit of gold-leaf to nutter so speedily as 

 almost to obscure its shape, and give it the appearance of an 

 insect busily plying its wings. When the hand is approached, 

 the fluttering ceases, and the little swimmer floats tranquilly in 

 the atmosphere. So strong is the electric wind proceeding from 

 the floating scrap, that it can be distinctly felt, as a cold draft, 

 at a distance of 5 or 6 inches. 



XXXIV. Proceedings of Learned Societies. 



ROYAL SOCIETY. 



[Continued from p. 156.] 

 Nov. 16, 1854.— Colonel Sabine, R.A.,V.P. and Treas., in the Chair. 



THE following communications were read : — 

 " Observations on the Respiratory Movements of Insects." 

 By the late William Frederick Barlow, F.R.C.S. Arranged and 

 communicated by James Paget, F.R.S. 



This essay contains the greater part of a series of observations 

 made between 1845 and 1850. The following are some of the 

 conclusions which they plainly indicate : — 



(1.) The respiratory movements of Dragon-flies (Libellulre), and, 

 probably, of other insects also, are naturally subject to considerable 

 and frequent variations in force and rate, the causes of many of 

 these variations being as yet unknown. 



(2.) The respirations of these insects are always quickened by 

 exercise, emotion, rise of temperature, galvanism, and mechanical 

 irritation; and the last three agents quicken them in the decapitated, 

 as well as in the perfect, insect. 



(3.) The respiratory movements of each segment of the trunk are, 

 in some measure, independent of those of the rest, although in the 

 perfect insect they concur in all the segments. They continue to 

 be performed, though feebly and slowly, in separated segments, pro- 

 vided their nervous cords and ganglia are entire : and they may be 

 abolished in single and successive segments by the local action of 

 chloroform. 



(4.) The removal of the head, including the supra- and sub-ceso- 

 phageal ganglia, does not, like the removal of the medulla oblongata 

 of the vertebrate animal, put a stop to the respirator)' movements of 

 the insect ; but it diminishes their frequency and force;, and deprives 

 them of all influence of the will and of mental emotions. 



(5.) The shock inflicted by the sudden destruction of the head, or 

 of the terminal part of the abdomen, generally stops all the respira- 

 tory movements of the insect for a time, and much enfeebles them 

 daring the remainder of its fife. 



(6.) The general tendency of the observations is to corroborate 

 the opinion of the self-sufficiency of the several ganglia for the 



