of the Circulation of the Blood in Insects. 4.9 
oe of Animals, 1827), of a distinct circulation of the 
blood in insects; and having had the advantage, within these 
few days, of witnessing some of the most striking facts upon 
which his discov ery ae which he had the goodness himself 
to show and explain to me, I am anxious that your entomolo- 
gical readers should partake of the high gratification which 
fi interesting sight imparted to me; hich any one might 
enjoy, who will examine some ver y common insects ‘with a wood 
compound microscope. 
The first insect to which Dr. Carus directed my attention 
was the larva of Ephémera vulgata (or an allied species), in 
which, near to the branchize and parallel with each side of the 
body, was very distinctly visible a constant current, towards 
the tail, of oblong lobules swimming in a transparent fluid, 
Colo} 
propelled with a regular pulsating motion; and on cutting the 
body of the larva across near the tail, these globules were most 
plainly seen pushed out of the div ided vessels in a distinct mass, 
which increased at each pulsation. I cannot express the plea- 
sure which it gave me to see thus clearly this ocular demon- 
stration of one Ta the most important physiological discoveries 
of modern times; and my gratification was heightened by the 
next object which Dr. Carus placed before his microscope, viz. a 
specimen of Sémblis viridis, in which precisely the same phe- 
nomena, but if possible more clearly, were seen in the nervures 
of the wings and in the antenne, in both which the constant 
current of globules was most apparent; and in the former, the 
sudden turning of these globules at the apex of the wing, out 
of the exterior nervure into a central one, with which it joins 
and forms an acute angle, was equally curious and striking. 
On cutting off the end of the antennze, precisely the same 
emission of globules (which soon assume a greenish tint) took 
place as in the former case, forming a mass which was increased 
with a sudden gush at each pulsation. 
Dr. Carus has observed the same phenomena in the wings 
of Sémblis bilineata, and in the elytra of Zampyris noctiltca aul 
L. itdlica, as well as in the fin-like appendages at the tail of 
the larva of A’grion puella, in which he first made the discovery, 
and in which the circulation is remarkably distinct. 
The only point of manipulation in examining the specimens 
which it is necessary to notice is, that Dr. Carus places them 
on the slip of glass, not in mere water, but in a drop of pretty 
thick gum water, which confines their too agile movements 
without i injuring the transparency of the medium. 
I must not omit observing, that when Dr. Carus was in 
Italy last year, he made some new and curious observations 
relative to the connection which exists between the circulation 
Vor, — No. 11. E 
