100 PHYSIOLOGICAL INQUIRIES. 
its mandible or jaws,—a distinct and complete organ, placed in front of 
the mouth, and visibly intended to nourish and protect the still feeble 
being. 
Behind this active apparatus he detected on the sides of the body 
a passive apparatus, a series of tiny mouths or valves (the stigmata) 
which await the air, and open to receive it. 
Ingenious precautions! The orphan born completely naked, and 
launched into life unprotected to undergo the most toilsome metamor- 
phoses, is rendered competent for the task only by eating greedily 
from the moment of its birth, absorbing and devouring! It must eat 
always and everywhere, even in the least respirable atmosphere, and in 
unhealthy and deadly places. It is for this reason nature has endowed 
it with a slower, and, if I may so speak, a more suspicious circulation 
and respiration, than that of the superior creatures which live only in 
pure air. In these creatures, as in man, the blood continually flows to 
meet the air and be vivified by it. In the insect, on the contrary, the 
protecting apparatus which guards its lateral mouths are disposed in 
such a manner as to be able always to moderate, sift, and, if need be, 
exclude, the invading atmosphere. ‘One is overcome with surprise by the 
infinite variety of the combinations designed for this end, the numerous 
mechanical and chemical arts of the most complicated character. To 
receive and yet not receive, to breathe without breathing, to preserve 
the control of what must nevertheless be a passive function, to trust 
and yet mistrust, to surrender and yet protect, is the difficult problem 
which life here proposed to itself, and of which it has found innumer- 
able solutions. To give air to a grub! Behold, arrogant humanity, 
which callest thyself the centre of all things, the most laborious effort 
that has engrossed the powers of nature ! 
Its circulation resembles that of the embryo in the bosom of its 
mother. But how much less favourable the condition of the insect! 
The foetus is in immediate contact with the world through the soft 
maternal medium. The motherless insect embryo does not swim, like 
the other, in a sea of milk. It is cradled in the rude mould of the 
universal life ; it travels therein at great peril, on the rude earth, from 
shock to shock. 
