226 EDITOR ON CIRCULATION HST INSECTS. 



covered about ten o'clock at night, and the bird-catcher must remain 

 by it till daybreak, when, if his net is in readiness, he may be sure to 

 lake it. I had one night singer last spring, which struck up the fourth 

 evening after he was caught. 



Bonn on the Rhine. 



ON THE DISCOVERY OF THE CIRCULATION OF THE FLUIDS 



IN INSECTS. 



BY THE EDITOR. 



In INSECT TRANSFORMATIONS, published in 1830, I have said 

 respecting certain alleged discoveries of the circulation of the blood, or 

 the fluid similar to blood, in insects, that they " furnish no proof what- 

 ever of a general circulatory system, though they appear to indicate 

 local movements ;" and in the ALPHABET OF INSECTS published in 

 1832, I have said, " there is not, and cannot be any real or direct cir- 

 culation of blood in insects." These are the result of as careful and 

 cautious an investigation of the facts as it was possible for me to make, 

 and my conclusion has not been in the least shaken by anything that 

 has been, so far as I know, subsequently published; for though I have 

 met with an alleged more recent discovery of the circulation in inserts, 

 this is decidedly nothing more than a repetition of what has been well 

 known from the time of Lyonnet and Comparetti, and more lately from 

 the works of Straus-Diirckheim, and Dr. Carus of Dresden. The opi- 

 nion of Lyonnet is well known, and Bonnet has given a luminous 

 abstract of it, and agrees with the author in a note to his Contempla- 

 tions de la Nature (iii. 19). Comparetti, who in 1800 investigated the 

 subject with great minuteness in the grubs of Ephemerae, and numerous 

 other insects, says, " the vascular system of the circulation begins from 

 the pulsating dorsal trunk," [cceur, STRAUS ; grande artere, LYON- 

 NET] " and proceeds by very minute branches through every external 

 and internal part, of the abdomen, of the corselet, of the head, and of 

 the members, flowing back to the greater non-pulsating trunks." He 

 concludes that " the manner in which the fluid of the insect is conveyed 

 to the pulsating organ, with the various properties of the vascular system, 

 remain to be demonstrated*." 



* I subjoin the original Italian of the passages which I have here translated. 



