CHA P. II.

SECTION II.

OF THE INTERNAL PARTS OF INSECTS.

LET us now come to the internal parts of infects, and let us fcrutinize the inmoft receffes of their structure in order to penetrate into the myfteries of nature. The task is full of difficulty. Many of thofe parts are fo fmall as to efcape our fight. To discover them we muft ufe the higheft magnifiers. Befides, the eye is weakened by the continued contemplation of one object, and we feel this fenfibly when we force. ourfelves to the tafk. Notwithstanding thefe difficulties, however, Naturalifts have difcovered many things on our prefent fubject; thefe I fhall detail, and add what I have learnt from my own obfer..

vations.

If we separate the external skin from an infect with inftruments, or throw it into warm water, that the fkin may come away of itself, we shall find that it covers many parts worthy of attention. And first in the head we difcern the brain, the fubftance of which is fo foft that it is not eafily examined even with a glafs. When we pierce the eyes of infects with a pin there iffues out a fluid, in fome clear like water, in others red like blood. Under the fkin is the flesh. It may well receive the name fince it confifts of fib

ro us

rous parts foft and fometimes reddifh as in other animals. The fibres are oblong parts, thin and flender like the fineft thread; their ufe is to connect the other parts with one another, and to put them in motion. They refemble wrinkles in the form of rings, and are diftinctly obfervable in infects when the mufcles are inactive; but when these are in motion they ftretch the fibres, and make them invifible. The exceffive delicacy of the fibres in infects has prevented hitherto our discovering whether they are enveloped with a fine membrane, like those of quadrupeds. In fome infects these fibres are fo fhort that their length is hardly equal to the breadth of three hairs; and therefore, they are not always to be feen, even with a glafs. As they ferve to extend, and to contract the muscles, their ftructure muft refemble that of a wire wound round a cylinder, when that cylinder is withdrawn. They vary their motion, folding themfelves in a femi-circle, fometimes to the right, fometimes to the left, nearly like a number of small worms. This motion, however, is very inconfiderable, and the fibres hardly change their fituation. After thefe, the flesh of infects appears, as in other animals. There are likewife fmall veins, which, joined to the nervous and fleshy fibres, compofe the mufcles.

Infects are deftitute of blood, properly fo called; because, the compofition of that fubftance demands ·more preparation and elaboration than can be performed in a body fo fmall as theirs; but, in place of blood, they have certain vifcid humours that serve the purposes of it. Thefe humours contain their animal fpirits, and from them infects draw their nourifhment. However fubtile they may be, they are, nevertheless, endowed with confiderable tenacity. In confequence of this quality, the head of a fly, after being cut off, will adhere again to its body, if fluck

on,

on, without, however, restoring it to life. This glu tinous quality of the humours enables infects to live for a time, after having been cut into two or more pieces; it prevents a rapid evaporation, it retains the humours which ftill continue to circulate for a time in the members, which would not happen without this quality. And, that this quality actually refides in the humours of infects, we may be convinced, by expofing them, when drawn from the animal, to the air, when they will fo dry, in a few minutes, as to become brittle like glue.

Infects have an artery; which is obfervable, runing along their back, and in which pulfation may be feen. The air produces in this artery the fame effect that blood does in circulation.

Infects eat and drink like other animals, a stomach is therefore neceffary to them. This is nothing but an extremely thin and hollow bag. The aliments of infects pass from the gullet into this ftomach, where they are digested and changed into a nutritive juice. Among quadrupeds, thofe that ruminate need more than one stomach, formed of feveral folds. It is the fame with infects; fome of them are found to ruminate, and confequently, have more than one ftomach. It is of this fort of infects that God permitted the Jews to eat. See LEVIT. CH. xi. 21. and 22.

Many perfons, not having obferved a heart in infects, have denied that they have any: but this is rafh. These animals have many parts, fo very minute, that they cannot be discovered; may this not be the cafe with the heart? Befides, there are many fpecies, in which this organ may be diftinctly feen. Laftly, the humours circulate in infects, and the arteries have a fort of pulfation; they muft, therefore, either have a heart or fomething analogous to it.

Lungs

Lungs have likewife been denied to infects. But, as respiration is neceffary to every creature, and as it is carried on by means of lungs, which are found in all the other animals, we cannot doubt but infects have them likewife. They are not of the fame fize, nor the same structure in all creatures; and those of infects are larger, in proportion, than those of other animals. This organ is formed in all, of little veficles, connected with one another. The air enters by the trachea, and goes out at the fame place. In'fects likewife have a trachea, which terminates in their lungs, but it is not of the fame ftructure with that in other animals. In thefe laft, it is formed of many cartilaginous rings; in infects it is nothing but fkin, which can be dilated or contracted with eafe. The lungs of other animals have branches, which, from the vena cava, difperfe themselves through the fubftance of the lungs, in many smaller branches. Infects have the fame, and by means of thefe, the air is diftributed to all their members.

In most infects, the intestines are a little different from those in the other animals. The minuteness of their bodies will not admit of so great a number. Accordingly, in many we find nothing but a tube, extending from the mouth to the vent, as may be seen in fuch as are tranfparent: It would appear, however, that, with refpect to the great gut, it is not in all of the fame figure, for the excrements of fome caterpillars are round, or cylindrical, and thofe of o thers have five furrows. This could not happen but from the structure of the rectum, which is the mould that gives the fæces their figure.

Round this long tube, are many flender fibres, which anfwer the purpose of veins and windpipe.

Bees have, towards the extremity of the abdomen
Y

a refervoir, which other infects have not. In this they depofite the honey which they have collected from flowers...

(

In the last place, it is to be remarked, that the females have an ovarium. This organ feems formed of a mass of fibres, which undoubtedly are veins.

What I have now obferved, with regard both to the external and internal parts of infects, proclaims, in the most explicit manner, the wifdom, and infinite power of the Creator. When we aflift at the dif fection of any of the larger animals, with what admiration does nor the fight affect us! the different members, their figure, the mufcles, the arteries, the veins, the lungs, the nerves, the bowels, every thing furprifes and aftonishes, for every where we discover the great and the wonderful; but the bulk of these animals is fufficient to contain fuch a variety of parts, and we are not furprised that they fhould find room there. What then ought to be our furprife, when, in diffecting the minuter infects, fuch as we are able to diffect, we difcover the fame members, the fame parts as in the moft enormous quadruped! What difplay of greatness, of wisdom, and power, in fuch a heap of parts, all equally perfect, and comprifed in fo fmall a fpace! Should the moft skilful artificer attempt to work on the fame defign, he might perhaps imitate the external parts of the larger infects; but how would he fail, in forming the fmall internal organs! Could he give his machine the power of fpontaneous motion! Could he communicate to it the power of propagating its like? All this is beyond the power of the most able workman, and can be performed, only by that infinite wisdom and power, which is the attribute of the Creator alone, the first and fole cause of all exiftences.

We