109 
CHAPTER! 
THE FIRST OBSERVATIONS ON “LITTLE ANIMALS” 
(PROTOZOA AND BACTERIA) IN WATERS 
(Letters 6, 13, 13a, 18, 188) 
EEUWENHOEK’S observations on the free-living 
le Protozoa probably began with his discovery of certain 
“very little animalcules”’ which he saw in fresh water 
in the year 1674. He described his findings in a letter 
addressed to Mr. Oldenburg,’ and dated from Delft, 
7 September 1674. This letter deals with other matters also, 
and the passage in which the Protozoa are mentioned is quite 
short. (See Plate XVII.) Here it is, in its entirety °: 
About two hours distant ® from this Town there lies an 
inland lake, called the Berkelse Mere, whose bottom in 
‘ Henry Oldenburg, Secretary of the Royal Society. See p. 38. 
2 Hrom Letter 6. 7 September 1674. MS.Roy.Soc. [Not in Dutch or 
Latin collected works.] Part of this letter was translated and printed in 
Phil. Trans., Vol. 1X, No. 108, pp. 178—182 [misprinted 821], 23 Nov. 
1674. It is numbered “ [10] Brief Tr. 7’ by Vandevelde (1922, p. 344), 
who gives an abstract of it in Flemish (from the Phil. Trans. version—not 
from the MS.). The important passage given above has been generally 
overlooked by protozoologists—possibly because the letter was omitted, 
apparently by an oversight, from the table of contents at the beginning of 
the number in which it was printed. The passage here given begins on 
p. 181; and I have followed the original translation pretty closely, because 
it is so lively and faithful. I havea strong feeling—but no direct evidence— 
that it was not the work of Oldenburg himself: but I do not know who the 
translator was. The English MS. has not been preserved.—I find since 
writing the above that attention was directed to this passage—as fixing the 
date of L.’s earliest observations—by Schill (1887), who reprinted the 
original English version. His note has seemingly been overlooked by all 
later writers. 
® John Ray, in his Journey through the Low-countries, notes (anno 1663) 
as a peculiarity that ‘ they reckon or measure their way in these Countreys, 
by the time they spend in passing it” (Ray, 1673; p. 93). 
