INTESTINAL PROTOZOA AND BACTERIA O27 
of an ashen colour, I viewed it’ through a common 
microscope, that I had by me; and I found that what 
gave it the ashen colour were globule-like particles, of 
sundry sizes, each of ’em made up of still lesser globules 
stuck together. And these last globules were as big as 
the globules of our blood, and each of these again consisted 
of six several globules. I can’t describe the first sort of 
globules better than by likening them to a round bunch 
of grapes, growing very close together, as it looks to your 
naked eye ; and although the particles were not perfectly 
round, yet I may call ’em globules, for they were wanting 
in nothing but that those which were as big as a blood- 
globule (which I have already described as compound) 
stuck out a bit on the outside, like each grape does from 
its bunch.” Of this matter I took up a little, and found 
that besides the globules aforementioned there were yet 
many others, which had a sixth of the bigness of one of 
our blood-globules, and also some whereof I judged that 
36 of ’em together would only make up the bulk of a 
blood-globule.° 
which would be covered in an hour and a half by a man on foot. (Cf. note 
3 on p. 109 supra.) The Latin translator—who copies the time from 
the printed Dutch version, not the MS.—accordingly renders this phrase 
(correctly) as “ circiter horam atque horae quadrantem pedestris itineris. . .” 
' In an earlier communication (Letter 38, 12 Noy. 1680), L. mentions 
that he examined his own urine, at a time when he was sick, and found in 
it—in addition to numerous particles—several red blood-corpuscles (ef. p. 12 
of Dutch printed version). 
* This is a hard sentence to translate closely and intelligibly. I give it 
as near as I can—without improving it too much. 
* The foregoing observations—though they record the discovery of no 
new animalcules—appear to me to be of great importance; for they show 
that L. really recognized living bacteria when he saw them. He did not 
here—or elsewhere—mistake minute inanimate particles for “‘animalcules.”’ 
At first sight it may seem strange that he did not take all minute moving 
particles for living organisms—as would have been indeed excusable. 
‘“ Brownian movement’ was not “ discovered ” until a century and a half 
later: but the phenomenon itself must have been frequently witnessed by 
L. He accounted for it as a consequence of the heat imparted to his 
microscopic preparations by their proximity to his own body. (He had to 
hold his microscopes very close to his face, because of the very short focus 
of his lenses.) 
