444 
Second Report of Experiments of the 
After the change of form has taken place the length is only 
about -07 mm. Growth is very rapid, so that by the end of 
the third day the sporocyst has increased to "15 mm. in length, 
still preserving the elliptical form. After this time growth is 
most rapid in the longitudinal direction, and the form becomes 
sack-shaped. At the end of a week the length is about '22 mm. 
The rudimentary digestive tract remains for a time, but later 
on is no lonsrer distinguishable. The 
germinal cells filling: 
the 
sporocyst are now much more numerous, partly perhaps owing 
to the division of those already present in the embryo, but more 
especially owing to a proliferation of the cells of the inner wall 
of the sporocyst. If the sporocyst be much contracted, the ger- 
minal cells seem to fill up the whole of the space, and the cells 
which are still attached to the body-wall, and form part of its 
inner surface, cannot be distinguished from those which are 
lying free. But if a sporocyst be chosen for examination which 
is not in a state of contraction, cells with large nuclei may be 
seen in the clearest possible manner projecting 
here and there from the inner surface ; some- 
times in a single layer, at other times in 
rounded heaps, two or three cells deep. At 
about the beginning of the second week the 
mass of germinal cells is first seen to be 
breaking up into separate balls of cells — the 
germs of the next generation. The sporo- 
cyst continues to increase in size, the papilla 
is still seen at one end, and the two eye- 
spots behind, these often getting widely 
separated. Instead of the two ciliated fun- 
nels of the excretory system of the embryo, we 
may now distinguish as many as ten in the 
sporocyst, all being situated about the middle of the body. In 
each funnel may be seen a single large tongue-shaped cilium, 
carried by a nucleated cell. The vessels into which these funnels 
might be supposed to lead cannot be clearly seen. As the germs 
within the sporocyst increase in size they assume an oval and 
then a more oblong form. All the germs within a given spo- 
rocyst are not at the same stage of development. There is 
generally a single large one, with two or three of medium size, 
and several small ones. By the eleventh day we se^ that the 
germs are not destined to form a brood of cercaria», that is, 
of those forms which enter into the sheep, but that they will 
form a second generation, reproducing asexually by the forma- 
tion of spores within the body-cavity. In the most advanced 
germs which have the oblong form, we may now distinguish 
cells arranged to form a nearly spherical pharynx, which leads 
JCmbryo of Liver-fluke 
soon after it has set- 
tled in the snail. Rlag- 
nified 370 diameters. 
