EDITOR ON CIRCULATION IN INSECTS. 227 



Even before this, however, the illustrious discoverer of the circulation 

 of the blood, says that " in bees, flies, and wasps, the heart could be dis- 

 tinguished by means of a magnifying glass* and M. Lesser also 

 expressly says, " the fluids circulate in insects, and the arteries have a 

 sort of pulsation, which consequently indicates a heart, or something 

 similar f." Baker again speaks of the current of blood being remark- 

 ably visible in the legs of some small bugs, and he observed a green 

 fluid passing through the vessels of the wings of grasshoppers. 



The late Baron Cuvier, after trying all the usual modes of injecting 

 the great dorsal vessel of insects, as Lyonnet had previously done \, 

 could not discover the slightest trace of outlet or inlet thereto, than 

 which nothing could be more decisive against a direct circulation ; and 

 M. Marcel de Serres, in 1819, in some experiments not very justifiable, 

 succeeded in removing this dorsal vessel, without causing the death of 

 the insect ; but if it were a heart circulating blood, it is impossible 

 that the insect could live without it. 



In 1824, Dr. Carus of Dresden published an essay in which he lays 

 claim to the discovery of a circulating system in insects, particularly in 

 the grub of the common day fly {Ephemera vulgataj, at the same time 

 confessing (and this is an important point) that the circulation ceases 

 in the adult insects, a circumstance for which he endeavours to account 

 on a similar principle to the obliteration of the blood vessels in the bones 

 and feathers of adult birds. Dr. Carus, however, is clearly of opinion 

 that e f the insect blood in its currents is not confined to vessels," like 

 the blood of larger animals§. 



In 1826, Messrs. Kirby and Spence, after examining the opinions of 

 previous authors, with the exception of Lesser, Comparetti, and Bonnet, 

 conclude very justly, as I still think, that " there is clearly no circula- 

 tion." But one of these authors, Mr. Spence, writing from Dresden, 

 28th of August, 1829, admits the discovery of Carus. " The first 



" II sisteraa vascolare della circolazione, comincia dal tronco dorsale pulsante, e 

 progredisce pe' rami li piu fini per ogni parte esterna, ed interna, dell 5 addome, del 

 torace, del capo, e de' membri, ricorrendo a* tronchi maggiore non pulsanti.'" 

 " Resterrebe dimostrato il modo, con cui il liquido dell" insetto si porti all' organo 

 sante colla diversa qualita. del sistema vascolare." — Cgmpabetti, Dinamica Ani- 

 mate, 8vo, Padova, 1800, part i. pp 230 and 236* 



* Harvieus, de Motu Cordis, c. 17. 



f Theologie des Insectes, ii. p. 91, 8vo, a la Haye, 1742. 

 X Anatomic de Chenille, p. 427. 



§ Cams, Entdeckung eines einfaehen vom Herzen aus beschleunigter Blut- 

 kreislaufes in den Larven netzfluglicher Insecten. 4to, Leipzig, 1824. 



Q 2 



