Of Animalcula in Fluids. 1 63 
out of its Iheath N O, it extruded at the fame time that 
furprifing wheel-work (which before was taken for two 
diftindl little wheels, and was here plainly feen to be 
but one and the fame circumvolution) that con filled of 
four round parts P QJR. S, three of which were to b« 
feen, the fourth being almoll hid ; its motion was from 
P to Q, according to the order of the letters. Fig. 320. 
reprefents the wheel-'work by itfelf, and larger than it 
appeared to the fight. 
Mr. Leeuwenhoek found feveral kinds of thefe wheel- 
work animalcula in the Hi my matter which is to be found 
in leaden pipes, or 1 gutters; when the water dries away 
they contradl themfelves into an oval figure, and a reddilh 
colour, and become fixed in the dry dirt, which grows 
as hard as clay ; but if to this dirt you put water, in a- 
bout half an hour’s time they open, and by degrees ex¬ 
tend their bodies and fwim about; and this they did after 
fome of this gutter-dirt had been kept dry for twenty- 
one months together: whence he concludes, that the 
pores of their fkin are fo perfedly doled as to prevent all 
perfpiration, by which means they are preferyed till rain 
falls, when they open their bodies, fwim about, and take 
in nourilhment. 
Fig. 321. and 322. reprefents two of them in different 
pofitions, and fig. 323. Ihews how they appear when dry 
and contradled. 
Several fpecies both of cruftaceOus and tellaceous ani¬ 
malcules are to be found in the waters of ditches 5 two 
of the former fort are reprefented in fig. 324. 325. in the 
pollure they fwim with their backs next the eye; their 
legs are fomething like thofe of fhrimps or lobilers, but 
of a llrudlure much more curious; they are lefs than a 
very fmali flea, are all breeders k , and carry their fpawn 
M2 ill 
1 Leeuwenhoek’s Arc. Nat. Tom. ii. ErjU. 149. k Phil, 
Tranf. No. 288. 
