248 
LEEUWENHOEK AND HIS “ LITTLE ANIMALS” 
Being unable to satisfy myself about this, I made up 
my mind to put my back into the job, and to look into 
the question as carefully as I could. But because I keep 
my teeth uncommon clean, rubbing them with salt every 
morning, and after meals generally picking them with a 
fowl’s quill, or pen; I therefore found very little of the said 
stuff stuck on the outside of my front teeth: and in what 
I got out from between them, I could find nothing with 
life in it. Thereupon I took a little of the stuff that was 
on my frontmost grinders; but though I had two or 
three shots at these observations, ’twas not till the third 
attempt that I saw one or two live animalcules. Yet I 
could well make out some particles lying about that I 
felt sure must have been animalcules. This put me in a 
quandary again, seeing that at and about the time when 
I wrote to you concerning these animalcules, I never 
failed to see there was life in them: but though now I 
used just the very same magnifying-glass and apparatus 
(which I judged to be that best suited to the purpose), 
yet I couldn’t make out any living creatures at all. 
Having allowed my speculations to run on this subject 
for some time, methinks I have now got to the bottom 
of the dying-off of these animalcules. The reason is, I 
mostly or pretty near always of a morning drink coffee, 
as hot as I can, so hot that it puts me into a sweat: 
beyond this I seldom drink anything save at mealtimes 
in the middle of the day and in the evening; and by 
doing so, I find myself in the best of health. Now the 
animalcules that are in the white matter on the front- 
teeth, and on the foremost of the back-teeth, being unable 
to bear the hotness of the coffee, are thereby killed: like 
I’ve often shown that the animalcules which are in water 
are made to die by a slight heating. 
Accordingly, I took (with the help of a magnifying 
mirror) the stuff from off and from between the teeth 
further back in my mouth, where the heat of the coffee 
couldn’t get at it. This stuff I mixt with a little spit 
out of my mouth (in which there were no air-bubbles), 
