:3 45 
C. DOBELL 
Further, I examined the bile from three old rabbits. The [bile of the] first contained a 
very few small globules, but very many oval corpuscles of a figure like those that, as I have 
said, I saw in the bile of an ox. In the bile of the two other rabbits there was nothing but 
globules, and irregular particles composed of globules joined together; though the thin 
matter [= liquid constituent] of one was much thicker and more viscid than that of the 
other, and there were some little clouds floating through it. 
I have further examined the bile of fowls, turkeys, etc., and in it I also found very little 
globules floating, and irregular particles composed of globules joined together. 
I would invite tlie reader’s attention especially to the concluding para¬ 
graphs of the foregoing extract, wherein Leeuwenhoek describes his observa¬ 
tions on the bile of rabbits. It will be observed that he examined altogether 
five of these animals—three old and two young ones. In the latter he found 
nothing but “particles” and “globules” (called deeltgens and clootgens in the 
original) which were, so he supposed, probably formed by precipitation and 
aggregation on cooling, and which were observed floating singly or clumped 
into irregular flakes. But in one of the three old rabbits he found, in addition 
to the “globules,” many “oval corpuscles” ( eijronde deeltgens) like those 
which he saw in the bile of oxen and sheep. I do not think there can be much 
doubt as to the correct interpretation of these discoveries. The egg-like bodies 
in the gall-bladders of sheep and oxen were undoubtedly the eggs of trema- 
todes; while those in the bile of the rabbit were no less certainly the oocysts 
of Eimeria stiedae. Let us consider these interpretations in more detail. 
From Leeuwenhoek’s account of the oval structures in the bile of the ox 
it appears to me certain that he was dealing with the eggs of Fasciola hepatica 
L., or some similar trematode. Their shape—resembling an “ant’s egg,” but 
not a hen’s egg—and their yellowish colour; their transparency under the 
microscope; their vesicular constitution, and their contained globules; their 
specific gravity—greater than that of the bile in which they floated; the fact 
that they possessed resistant but not inflexible shells—as is indicated by the 
experiment with the hair;—all these characters convince me that these “oval 
corpuscles ” were the eggs of liver-flukes. The distribution of these corpuscles 
in the various samples of bile examined is also most significant. It will be 
seen that Leeuwenhoek found them regularly in the bile of (adult) oxen, but 
in only one calf out of three examined: he found them in a year-old sheep, 
but not in lambs: and he did not find them at all in the bile of the birds which 
he studied. Moreover, he tells us that they varied in numbers in the different 
specimens of bile which he obtained from oxen. The observations are, therefore, 
exactly accordant with what we should expect if the objects which he found 
were the eggs of liver-flukes. 
I do not know whether these observations are the first ever made on the 
eggs of trematodes, but I think they probably were. The worms which lay 
these eggs were discovered, however, at an earlier date: for I find them men¬ 
tioned in the work of Redi (1668), who tells us they were called “ bisciuole 
da? macellai ,” and gives us (p. 190) a picture of one (Fasciola hepatica) from 
