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376 LEEUWENHOEK AND HIS “‘ LITTLE ANIMALS” 
names' were assigned to protozoa by John Hill’ in 1752, and 
that the first serious systematic treatment of both protozoa 
and bacteria was attempted in 1773 by O. F. Miiller*— 
revising and amplifying the inadequate account of these 
organisms given by Linnaeus* (1758, 1767). These three 
writers—an Englishman, a Dane, and a Swede—were all very 
remarkable men, in very different ways; yet they had this in 
common that they all respected Leeuwenhoek. Even the 
cavalier Hill—a bitter critic of the Royal Society and all its 
works (which he nevertheless copied’ freely for his own 
profit)—was forced to allow his merits. In one place he says, 
for example, “Even Lewenhoeck the Father, as he may be 
called, of this Branch of Observation, is not without his 
Mistakes, tho’ there are many more in Proportion in all 
that have followed him”.° 
Hill was an amateur microscopist, and he made no original 
contributions of value to protozoology: but though Linné 
was a professional naturalist, he had equally little know- 
ledge of the Protozoa—notwithstanding he made the first 
attempt to classify the micro-organisms known in his day. 
But Miller was a systematist with a good working knowledge 
of the “‘ Infusoria.”‘ He applied Linné’s system to organisms 
which he had himself seen and studied: and he was, withal, an 
1 They were pre-Linnaean and not binominal: yet some of them—such 
as Paramecium—are still current. 
2 Much has already been written about ‘Sir’? John Hill (1716-1775), 
though nobody has yet duly appraised his contributions to protozoology. 
Cf. especially the Dict. Nat. Biogr., T. G. Hill (1913), and Woodruff (1926). 
* Otto Friderich Miiller (1730-1784). Cf. Dansk Biogr. Lewx., XI, 594. 
The most recent estimate of him (chiefly as a botanist) is that of Christensen 
(1922, 1924). Biitschli fully appreciated his protozoological works, but no 
other recent student of the protozoa has attempted to assess or even interpret 
all his extremely important observations on these organisms. 
* Carl von Linné (1707-1778). For his life see especially Daydon 
Jackson (1923). 
° As an instance I may note that most of Hill’s figures of protozoa 
(1752) were boldly copied without acknowledgement from the anonymous 
writer of 1703—from the Phil. Trans. which he so affected to despise ! 
® Hill (1752a), p. 94. 
" Miiller’s “ Animalcula Infusoria”’ were a motley crew of microscopic 
creatures, comprising not only all the protozoa and bacteria then known, 
but also worms, rotifers, algae, and other organisms. 
