132 M. Dutowr’s Anatomical and Physiological Studies 
I have brought forward materials furnished by insects of every order, as 
well as the opinions expressed by all men of science. 
Among those who are in doubt about the existence of this circulation 
are Malpighi, Swammerdam, Lyonnet, Cuvier, MM. Marcel de Serres, 
Duméril, Duvernoy, Audouin, &c. ; and among those who contend for 
it are MM. Comparetti, Straus, Wagner, Carus, Behn, Duges, &c. We 
thus perceive that the most respectable and eminent names are to be 
found arrayed on both sides. 
Kverlasting fame be assigned to our illustrious Cuvier! At a period 
remote from our own (upwards of forty years ago) he had established, 
in reference to insects, by that inspiration which belongs to genius alone, 
this fundamental law of physiology, that the existence of an aériferous 
vescular apparatus excludes that of a sanguineous vascular apparatus ; 
or, to express it in the sacred words of this legislator in science, the nu- 
tritive fluid being unable to come into contact with the air, the air is caused 
to repair to it, in order to combine with it. Since that period, the progress 
of discovery occasions no necessity for modifying the expression of this 
law. It still preserves, in my opinion, all its spirit and force. 
It is very singular that instead of choosing the largest species of insects 
for the purpose of demonstrating a circulating system, the savans who 
contend for its existence, have, on the contrary, selected the most minute, 
usually larvee in their earliest stage, and the movements of a liquid con- 
tained in the cavities of the body, and seen thtough the pellucid integu- 
ments, have been considered sufficient to prove a circulation in these ani- 
mals. And yet the experiments and injections made by Cuvier, repeated 
on an extensive scale by M. Marcel de Serres, were altogether opposed 
to such a view of the subject. 
I have scrupulously analysed, and, I conceive, successfully opposed the 
specious and sometimes contradictory assertions of M. Carus, who con- 
siders that the circulation, the double circulation of insects, is carried on 
by currents of liquid, by vessels without walls, which he does not hesitate 
to qualify by the terms arterial and veinous, These currents, subject, in 
my opinion, to the laws of capillarity and organic affinities, cannot be 
regarded as constituting a circulating system. 
M. Straus has described and figured the supposed heart of a cockchafer, 
as being pierced with eight lateral pair of auriculo-ventricular openings, 
and the like number of ventricles or chambers separated by valvules. 
According to his view, the blood of the cavities enters the heart direetly 
by these openings, passes into the artery which crosses the thorax, and 
spreads itself over the head, whence it returns to the cavities. While 
admitting, along with M. Straus, the existence of a similar structure, I 
prove that we cannot reasonably adduce it, as he does, to demonstrate a 
double circulation. The movement, in my opinion, is limited to the con- 
tinual play of a siphon, which can never accomplish the physiological 
purpose of a circulation. My dissections of the same cockchafer have not 
enabled me to detect any opening in the dorsal organ of that insect. This 
