Some Observations made by a Microscope, contrived by M. LEUWENHOEK, in Holland. [1673.]

THE mould upon skin, flesh, or other things, has been by some represented to be shot out in the form of the stalks of vegetables, so as that some of those stalks appeared with round knobs at the end, some with blossom-like leaves. But I observe that such mould shoots up first with a straight transparent stalk, in which stalk is driven up a globous substance, which for the most part places itself at the top of the stalk, and is followed by another globule, driving out the first either sideways or at the top; and that is succeeded by a third and more such globules; all which make up at last one great knob on the stalk, a hundred times thicker than the stalk itself. And this knob indeed consists of nothing else than of many small roundish knobs, which being multiplied, the large knob begins to burst asunder, and then represents a kind of blossoms with leaves.

The sting of a bee I find of a different form than has been described by others. I have observed in it two other stings, that are lodged within the thickness of the first sting, each having its peculiar sheath.

Further, I observe, on the head of a bee before, two artus or limbs with teeth, which I call scrapers, conceiving them to be the organs with which the bee scrapes the waxy substance from the plant. Besides, I find two other limbs, each having two joints, which I call arms, with which I believe this insect performs its work and makes the combs. There is also a little body which I call the wiper, being rough, and exceeding the other limbs in thickness and length, by which I am apt to believe the bee wipes the honey substance from the plant. All which five limbs the bee, when at work, lays in a curious manner close under her head, in very good order.

As to the eye of the bee, which I have taken out of the head, exposing its innermost part to the microscope, I find, that the bee receives her light just with the same shadow as we see the honey-combs; whence I collect that the bee works not by art or knowledge, but only after the pattern of the light received in the eye.

In a louse I observe, indeed, as others have done, a short tapering nose with a hole in it, out of which that insect, when it will draw food, thrusts its sting, which, to my eye, was at least five and twenty times less than one single hair.

But I find the head every where else very close round about, and without any such sutures as some have represented it. The skin of the head is rough, resembling a skin that has many dents in it. In the two horns I find five joints, others having marked but four. One claw of her foot is of the structure of that of an eagle, but the other of the same foot stands out straight and is very small; and between these two claws there is a raised part or knob, the better to clasp and hold fast the hair.

In the engraving fig. a shows part of the sting taken out of the sheath and drawn a little sideways; whence it is, that the crooks or barbs do not show so large nor sharp as indeed they are.

Fig. b represents the whole sting, taken out of the sheath, and with its back, which is without barbs, turned to the eye. The upper part of the sting is closed round about, and hollow within, and the lower part is open.

In fig. e both the stings are seen, as they lie together before, close against the sheath, yet is one of them a little higher than the other; and forasmuch as

α

b

C

there is yet seen a little of the sheath, here both the stings seem to be one, furnished on both sides with barbs.

Fig. d. Both the stings in part out of their sheath, yet one stands a little higher out of the case than the other. Thus they are found to lie in their sheath when they are at rest.

As to the motion of these stings, I conceive it to be thus made: first the bee draws her sheath with its stings out of the body, and endeavours to thrust it as far as she can into the body she would sting, together with one of the stings, which at that time she draws out of the case; which sting, when she is drawing back again, but it not being able by reason of the barbs to return, she pulls the sheath and the other sting deeper into the body. Now it is that she uses her other sting, which she then thrusts also into the body as deep as she can, and then endeavours to pull that back also; by which pulling back she thrusts her sheath and first sting yet deeper into the body; and this she continues so long

till she gets both the stings and the sheath, as far as to the thick part of the sheath, into the body.

An Attempt to prove the Motion of the Earth from Observations made by ROBERT HOOK.-[1674.]

THE ingenious author of this attempt, having considered with himself, that the grand controversy about the earth remains yet undetermined, and finding there was no better means left for human industry to decide it but by observing, whether there be any sensible parallax of the earth's orbit among the fixed stars, did thereupon resolve to employ himself in making some observations concerning so important a point in astronomy. His method, which he gives an account of, is to observe, by the passing of some considerable star near the zenith of some place, whether such a star does not at one time of the year pass nearer to the zenith, and at another farther from it.

Accordingly he affirms to have actually made four observations; by which, he says, it is manifest, that there is a sensible parallax of the earth's orbit to the star in the dragon's head, and consequently a confirmation of the Copernican system against the Ptolemaic and Tychonic. At the end of the explication he mentions some things, which he looks upon as very remarkable, occurring in those observations; one of which was, that in the day-time, the sun shining very clear, he observed the bright star in the dragon's head to pass by the zenith as distinctly and clearly as if the sun had been set; which he esteems to have been the first time that the stars were seen when the sun shone very bright; that tradition, of seeing the stars in the day with the naked eye out of a deep well or mine, being by him judged a mere fiction, a thing he had deemed impossible.

Lastly, he promises that he will explain to the curious a system of the world, differing in many particulars from any yet known, but answering in all things to the common rules of mechanical motions; which system he here declares to depend on three suppositions: 1. That all celestial bodies whatsoever have an attraction or gravitating power towards their own centres, whereby they attract, not only their own parts, and keep them from flying from them, as we may observe the earth to do; but also all other celestial bodies that are within the sphere of their activity. 2. That all

bodies whatsoever, that are put into a direct and simple motion, will so continue to move forward in a straight line till they are by some other more effectual power deflected and bent into a motion that describes some curve line. 3. That these attractive powers are so much the more powerful in operating, by how much the nearer the body acted on is to their own centres./

Microscopical Observations made by M. LEUWENHOEK. — [1674.]

I HAVE observed by the microscope, that blood consists of small round globules driven through a crystalline humidity or water. I have likewise observed some of the sweet milk of cows, and find that also to be made up of small transparent globules, carried in the same manner as in the blood through a clear liquor.

I observed the hair of an elk, and found it wholly to consist of conjoined globules, which by my microscope appeared so manifestly to me, as if they could be handled; and therefore having so clearly seen those globules, I assure myself, that the growth and increment of hair is made by the protrusion and driving on of globules. This hair of the elk I find to be within much hollower, than that of men or of other animals.

Again, I also observed a nail of my hand, and found it likewise to be made up of globules, not doubting but that it also grows from globules protruded.

Having formerly spoken of the louse, her sting, &c. I cannot here omit to say something of what I have seen within that creature. I have several times put a hungry louse upon my hand, to observe her drawing blood from thence, and the subsequent motion of her body, which was thus the louse having fixed her sting in the skin, and now drawing blood, the blood passes to the fore part of the head in a fine stream, and then it falls into a larger round place, which I take to be filled with air. This large room being, as to its fore part, filled about half full with blood, then propels its blood backward, and the air forward again: and this is continued with great quickness, while the louse is drawing the blood; except that at times she stops a little, as if she were tired, and recollects herself; a motion like that, it seems, which is in the mouth of a sucking infant: from thence the blood passes in a fine stream into the midst of her

head, that being also a large round place, where it has the same motion. Hence it passes in a subtile stream to the breast, and thence into a gut, which goes to the hindmost part of the body, and with a curvity bends a little upwards again. In the breast and gut the blood is, without intermission, moved with great force, and especially in the gut; and that with such strong beatings downwards, and with such a retrocourse and contraction of the gut, that a curious eye cannot but admire the motion.

Microscopical Observations concerning Blood, Milk, Bones, and the Brain, &c. By M. LEUWENHOEK.

[1674.] THE small red globules in the blood are heavier than the crystalline liquor in which they are carried; because, soon after the blood is let out of the veins, those globules gradually subside towards the bottom; and consisting of soft fluid corpuscles, many of which lie on one another, they unite close together, by which conjunction the blood under its surface alters its colour, and becomes dark, red, or blackish. The red globules of the blood I reckon to be 25,000 times smaller than a grain of sand.

I have observed the tooth of a cow, and found it made up of transparent globules, which I can see very perfectly. The same I have observed in ivory or elephants' teeth. And I have no doubt but that all white bones do consist of transparent globules. I am of opinion, that all things which appear white to our eyes are made up of nothing but transparent particles lying one upon another, such as snow, white paper, linen, white stones, white wood, scum, beaten glass, beaten rosin, sugar, salt, &c.

The brains of a cow being viewed, I found the white substance of it to be made up also of very fine globules. As to the marrow of the back-bone, I found that also to consist of very subtile globules. Having divers times observed the flesh of a cow, I found it to consist of very slender filaments, lying by each other, as if woven into a film. I have also viewed several filaments which were beset with globules. These I judged to be blood, and that, pricking our body with a pin without hitting a vein, the bloody globules issued from between these filaments; but this I leave to further consideration. Mean time I have with a pin's point severed these filaments from one another, and found the single ones so fine, that any of them seemed to me 25 times thinner and finer