ON THE WHIP-WORM OF THE RAT’S LIVER. 87 
entiated into a worm, which was coiled up in a figure of eight ; 
gentle pressure of the cover glass caused expulsion of the embryos; 
fig. 1 shews the mature eggs, fig. 2 after pressure of the cover glass. 
Two white rats were fed with the mature eggs on August 23, 
24, 25, 1892; in three weeks these rats were seen to be ill, they 
suffered from dyspnoea, were emaciated, refused food and had 
diarrhea ; on September 19, one was killed, and on September 22, 
_ the other died ; their livers were diseased to an extent far exceed- 
ing anything previously seen, due of course to the large number 
of eggs which had been swallowed. The liver was pale yellow in 
colour, and was riddled with long thread-like worms and contained 
their eggs in thousands. The worms when microscopically 
examined were seen to be the parents of the eggs; it was impossible 
to dissect out a specimen unmutilated, so intricately were they 
intertwined and attached to the liver substance. I succeeded best. 
by squeezing pieces of the liver between two plates of glass, and 
afterwards teasing them under water with needles. Hardening 
the liver previously in alcohol increases the difficulty ; livers of 
very young rats are the best for this purpose. 
Many feeding experiments have been made, and with the result 
that if a large number of eggs are given, the rats die in three 
to four weeks ; if only a small number of eggs they recover, and 
if their livers be examined some months later, they will be found 
to have regained the normal state, but have white spots [egg 
masses | dotted over them. 
If a piece of the liver in which the 7richocephalus is burrowing 
to deposit its eggs be hardened and sections cut, many of the cells 
are seen to be in process of absorption, many have entirely dis- 
appeared, connective tissue elements taking their place. Those 
cells, which have not atrophied, are increased in size and have 
large nuclei, probably due to extra work being thrown upon them, 
either as scavengers of the dead cells or in carrying on the normal 
function of the liver, see Fig. 7. Atrophy of the cells is due to 
pressure of the worms, and seems to occur without cloudy swelling 
or fatty degeneration ; the protoplasm becomes absorbed, nothing 
