ANTHONY VAN LEEUWENHOECK 63 

 space between these two horns was flat, though the rest of the body 

 was roundish, sharpening a Httle towards the end, where they had a 

 tail, near four times the length of the whole body, of the thickness, 

 by my microscope, of a spider's web ; at the end of which appeared 

 a globule of the size of one of those which made up the body. These 

 little creatures, if they chanced to light on the least filament or string, 

 or other particle, were entangled therein, extending their body in a 

 long round, and endeavoring to disentangle their tail. Their motion 

 of extension and contraction continued a while; and I have seen 

 several thousands of these poor little creatures, within the space of a 

 grain of gross sand, lie fast clustered together in a few filaments. 



I also discovered a second sort, of an oval figure: and I imagined 

 their head to stand on a sharp end. These were a little longer than 

 the former. The inferior part of their body is flat, furnished with 

 several extremely thin feet, which moved very nimbly. The upper 

 part of the body was round, and had within 8, 10, or 12 globules, 

 where they were very clear. These little animals sometimes changed 

 their figure into a perfect round, especially when they came to lie 

 on a dry place. Their body was also very flexible; for as soon as 

 they struck against the smallest fibre or string, their body was bent 

 in, which bending presently jerked out again. When I put any of 

 them on a dry place, I observed that, changing themselves into a 

 round, their body was raised pyramidal-wise, with an extant point in 

 the middle ; and having laid thus a little while, with a motion of their 

 feet, they burst asunder, and the globules were presently diffused 

 and dissipated, so that I could not discern the least thing of any film, 

 in which the globules had doubtless been enclosed ; and at this time 

 of their bursting asunder, I was able to discover more globules than 

 when they were alive. 



I observed a third sort of little animals, that were twice as long as 

 broad, and to my eye eight times smaller than the first. Yet I thought 

 I discerned little feet, whereby they moved very briskly, both in round 

 and straight line. 



There was a fourth sort, which were so small that I was not able 

 to give them any figure at all. These were a thousand times smaller 

 than the eye of a large louse. These exceeded all the former in 

 celerity. I have often observed them to stand still as it were on a 

 point, and then turn themselves about with that swiftness, as we see a 



