10 Proceedings of the Royal Physical Society. 
These often had a kind of whirling motion, and sometimes 
moved in the direction represented by the dotted line CD 
(in curves and circles): these were more in number. Of the 
third sort I could not well ascertain the figure, for sometimes 
these seemed roundish or oblong, and sometimes perfectly 
round (bacterium or micrococcus): these were so small that 
they did not appear larger than represented at E. The 
motion of these little creatures one among another may be 
imagined like that of a great number of gnats or flies sporting 
in the air. From the appearance of these, to me, I judged 
that I saw some thousands of them in a portion of liquid 
no larger than a grain of sand, and this liquid consisted of 
8 parts water and 1 part only of the before-mentioned sub- 
stance taken from the teeth.” Nine years later he gave a 
much fuller description, and also described organisms which 
were evidently spirilla with their characteristic movements, 
as he says that these organisms “ move their bodies in com- 
paratively marked curves, swam forwards or backwards, or 
twisted themselves in an extremely lively fashion.” As was 
very natural, Kircher’s “ worms,’ as the fons et origo mali, 
were replaced by these wonderful little organisms described 
by Leeuwenhoek; and Nicolas Andry, putting Kircher’s 
theory and Leeuwenhoek’s observations together, evolved a 
germ theory, not only of disease, but of putrefaction and 
fermentation. He held that air, water, vinegar, fermenting 
wine, old beer, and sour milk were all full of germs; that 
germs were also contained in the blood and pustules of 
small-pox patients; in fact, these germs became so widely 
talked of that, as Loeffler points out, these inconceivable 
worms became the legitimate butts for the shafts of ridicule, 
and in 1726 there appeared in Paris a satirical work in which 
these small organisms received the name of “ fainter,” “ body 
pincher,” “ulcerator,” “weeping fistula,” “sensualist,” and so 
on. So well was this done, and so ridiculous was the whole 
system made to appear by the satire that was directed against 
it, that it became completely discredited, and so for long was 
only mentioned to be ridiculed. lLinneus, however, with 
his wonderful powers of observation and deduction, became 
convinced that in these organisms might lie, not only the 
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