26 
Experiments on the Development of the Liver-Jluke. 
teen days later, immediately after it had left the infected field. 
The greater part of the liver was still of the normal colour, but 
was marked with yellow spots and small lumps, and mottled 
with red patches which on pressure exuded a red ooze. The bile- 
ducts in the hilum of the liver were hardly thickened or dilated, 
but in the more distant parts were thickened just for an inch 
where a fluke lay. None of the flukes were full-sized, though 
two or three were 20 mm. long and contained ova, whilst the ma- 
jority were not much more than 8-14 mm. long, and the smallest 
measured only 2 mm. In another case the flukes contained in the 
liver of a lamb killed 2J weeks after removal from the source of 
infection, measured 6-10 mm. in length. From these and similar 
observations I believe that the fluke takes five or six weeks in 
attaining sexual maturity. At the time it enters the liver it is 
probably less than 0"5 mm. long. 
Duration of Life. — The liver-fluke is supposed to pass out of 
the sheep at the beginning of the summer, i.e. its life lasts only 
three-quarters of a year. Gerlach says that the fluke always passes 
out in the months of June and July, but Pech * states that he 
saw flukes pass out from rotten sheep in the autumn and winter, 
and suggests that they may have lived in the sheep more than a 
year. 1 have examined the droppings of sheep in June, which 
were asserted to contain dead flukes, but the so-called flukes 
proved on microscopic examination to be masses of mucus of 
very much the same colour as a fluke. The question is one of 
great importance, for if the fluke can live more than one year, it 
will scarcely be worth while attempting to keep the sheep alive 
until the natural limit of the fluke's life is reached. Three ewes 
which took the rot in the autumn of 1879, were received at the 
Royal Agricultural College, Cirencester, and have been under 
treatment since February 1880. The case has been described 
by Professor Mayer, in a lecture since published. The first was 
killed in April, and in December the other two were passing 
great quantities of ova, and as one of them appeared weakly and 
likely to die, it was killed on the 18th. The bile-ducts were 
filled with flukes, and others occurred in the gall-bladder and in 
the commencement of the intestine. 
I am indebted to the courtesy of Professor Stuart for one-half 
of this liver, and in this portion found 100 flukes. The bile- 
ducts were thickened, as usual, and the liver was pale, but there 
was no atrophy of the hepatic cells, and there was much less 
connective tissue than is usually found in a liver where the 
disease is of such long date. This was no doubt due to the 
care and generous diet bestowed upon the ewe, and if the fluke 
* ' Thierarzt,' 1873, p. 87. 
