112 
TTie Rot in Sheep. 
— thereby giving evidence of their being ciliated bodies ; but the 
object-glasses then at our command were insufficient in magni- 
fying power to bring the cilia into view. After this time, more 
and more of the ova parted with their opercula, always with 
a proportionate increase in the number of ciixular-shaped em- 
bryos. Judging from the developing process as seen to be going 
on in the interior of an ovum from the first gathering together 
of the yelk to the formation of cells, we reckoned that five or six 
embryos weie yielded by each ovum. 
In a short time numerous infusoria — poly gastric monads — 
existed in the fluid, which were slow in their movements, devoid 
of colour, and in some other respects very similar to the Monas 
enchelis of Pritchard ; but whether these were produced by an elon- 
gation of the original circular-shaped embryos of the fluke into the 
ovoid form of the monad, we could not satisfactorily determine. 
Throughout the entire year of 1854 a gradual increase of detached 
opercula took place, but at its close, and even down to April 
15, 1855, when our observations were discontinued, a very large 
number of ova were as perfect in appearance as when originally 
placed in the water. Circular-shaped embryos, and flattened, 
flask-shaped monads were still abundant, but no higher form of 
animal life could be detected. 
We have given the particulars of this experiment, because we 
consider that everything which tends to create thought is of the 
first importance in studying the history of the liver-fluke, and of 
material use in helping us to explain many of the phenomena 
connected with an outbreak of rot. 
Several analogous instances of the long preservation of the 
germs of future creatures within the egg can be adduced. 
Kiichenmeister, in describing the treatment for Ascarides, says : 
" The first thing to be done by the surgeon in practice consists 
in the destroying the eggs of the Ascarides whenever he meets 
Avith them, and exterminating every female that he can get at. 
It was H. E. Richtcr's merit that he first ascertained that the 
eggs remain uninjured in sewage, &c. Recently Barry, BischofF, 
and others have proved that the process of segmentation of the 
eggs of Nematoida continues even in very concentrated alkalies or 
salts. According to the experiments of Verloren and Richter, 
already described, the eggs of Ascarides only attain their full 
maturity when free in nature (in water), and only undergo the 
process of segmentation in this situation. In the various species 
of Ascarides the time necessary for this purpose may be different ; 
for whilst, according to Verloren, this is completed in one species 
of Ascaris within a few weeks, the eggs of the Ascaris lumhricoides 
require at least eleven to twelve months for the purpose. Even 
Richter's first statement spoke of such a period : according to a 
