292 LEEUWENHOEK AND HIS ‘‘ LITTLE ANIMALS 
Notwithstanding I have so many times seen such 
animalcules,’ and let others see ’em too, yet one can’t be 
satisfied with just looking at* so wonderful a structure: 
chiefly because one can’t get clear on how such an 
unbelievable motion is brought about, and in the second 
place, as to what purpose this motion was for. For when 
we see any part of such a creature (that is endowed with 
motion *) moved,* we feel sure that this part wasn’t made 
for nothing, but is a necessary part of it; and conse- 
quently this wheelwork is of use to the animalcule’s body, 
though we can’t call to mind just what use it is.’ 
He then records some further observations on Rotifers— 
made “at the end of July and the beginning of August 
[1712] ’—and proceeds : 
Furthermore, I paid great attention to their revolving 
toothed wheelwork; and I saw that an incredibly great 
motion was brought about by the said instrument, in 
the water round about it, whereby many little particles, 
that could be made out with the magnifying-glass, were 
wafted towards the animalcule, while others were carried 
away from it; whereof some, being borne into the middle 
of the revolving instrument, were used as food by the 
animalcule.’ And other particles, when they got up to it, 
went off from the animalcule as quick as if it flung them 
away; seeing which, I came to the conclusion that the 
cast-off particles were no good to the creature for food. 
From this observation we may well conclude that, since 
1 Called Dierkens throughout in the Dutch printed version, but Dieryens 
in the MS. 
* te beschouwen: these words are in the printed version but not in 
the MS. 
° The words in parenthesis are in the MS. but not in the printed version. 
4 bewegen MS. dat bewogen werd printed version. 
° 4s printed version was MS. 
5 van het Dierke als tot spys gebruykt wierden Dutch printed version. 
The MS. says het Dierke als tot spijs gebruijkte (the animalcule used as 
food). 
