VOL. XXII.] PHILOSOPHICAL TRANSACTIONS. 509 



Concerning IVorms pretended to be taken from the Teeth. Bi/ M. Leuwenhoeck, 



F. R.S. N°265, p. 633. 



Julij 27, 1700. 



On the receipt of your letter I immediately opened the piece of black silk 

 contained in it, where I found two little worms dead and one alive, which were 

 sent you to be conveyed to me, as being taken out of a corrupt tooth by 

 smoking. 



I had not spent much time in examining the living worm which wanted 

 above one half of its full growth, when I concluded that it sprung from the egg 

 of a small fly, of that sort that mostly frequent cheesemongers' shops, and lay 

 their eggs on the cheese ; now the worms taking their rise from those eggs, 

 they bore through the cheese, and take their nourishment and growth from it ; 

 and afterwards become little flies again. When these little worms arrive at such 

 a bulk as is discernible by the naked eye, we call them worms. 



I took a small glass tube, hermetically sealed at one end, and put into it the 

 living worm, together with some crumbs of very old and fat cheese, to try if the 

 worm, feeding on the cheese, would come to its full growth. I stopped the 

 glass with a cork: For I am positive that a worm may live and grow in a glass as 

 well as in a firm cheese covered up all about. Being confident that both the 

 dead worms and the living one were of the above-mentioned sort, I got a cheese- 

 monger to single out that sort of old cheese and bring some of its little worms 

 to my house. I put 6 or 8 of the largest of these worms in two distinct little 

 glasses, together with one of the dead worms you sent me, designing to com- 

 pare the living and dead worms before a magnifying glass: and could not descry 

 the least difference, either in the head or the whole body. 



When these worms had been shut up 5 days without any food, I observed 

 them gnawing the corks that stopped the glasses. Then I put in/i little cheese, ■ 

 that if they did not arrive at their full growth, they might not want food, in 

 order to their change into flies. I likewise endeavoured to bring one of these 

 worms to an extended and quiet posture, in order to view the internal parts, 

 which succeeded with me several times ; and saw to my great admiration, such 

 moving instruments all over the body within, that not one of a thousand would 

 be persuaded to believe that in such a contemptible insect there is so much to 

 be seen ; for in one place I thought I saw the motion of the heart, and near 

 that the motion of the stomach : but after all the closest inquiry, I could not 

 descry any motion in the blood in those parts which I took for veins. 



I would fain know what food these creatures live upon besides cheese. In 

 the first place, because I never yet saw them any where else but in cheese ; and 



