JOURNAL 
OF THE 
PtOYAL AGRICULTURAL SOCIETY 
OF ENGLAND. 
I. — Report of Experiments on the Development of the Liver-Fluhe 
(Fasciola hepatica). By A. P. Thomas, B.A., Demonstrator 
of Anatomy, University Museum, Oxford. 
1. The Ef/g and Embryo of the Fluke. — The eggs of the liver- 
fluke occur in very large numbers in the contents of the bile- 
clucts and gall-bladder of the infected animal. They give a 
dark-brown colour and sandy appearance to the bile, and in 
some of the smaller terminal ducts often form a stiff brown 
mass completely plugging up the lumen. They pass with the 
bile into the intestines, and may be found abundantly in the 
droppings of rotten sheep. 
The egg is an oval body with a smooth, transparent, yellowish- 
brown, chitinous shell. The average size may be said to be 
0*13 mm. in length by 0*08 mm. in breadth, but the dimensions 
vary greatly, the length from 0"105 mm. to 0"145mm., and the 
breadth from 0'066 mm. to 0*09 mm. The anterior end is a little 
more rounded than the posterior, and has a line running around 
it, which marks off a circular segment forming a cap or oper- 
culum 0 028 mm. in diameter. The opposite end is frequently 
a little thicker and slightly roughened. 
The number of eggs produced by a single fluke is exceedingly 
large, and its fecundity has been under-rated. Leuckart has 
estimated that the oviduct can contain as many as 45,000 eggs. 
In one case I obtained 7,400,000 eggs from the gall-bladder of 
a sheep suffering from the rot, and as the liver contained about 
200 flukes, this gives an average of 37,000 eggs to each fluke. 
And these eggs were found in the gall-bladder alone ; the liver 
must have contained at least as many more, and eggs had 
been passed copiously by the sheep for some months past. 
The number of eggs produced by a single fluke may be safely 
estimated at several hundred thousands. 
VOL. XVII. — S. S. B 
