164 
POPULAE SCIENCE EEVIEW. 
ic 
parasites undergo — that they are at least the source of one or 
more of the fluke parasites which occasionally 
invade our frames. The following case will 
best illustrate my subject : — young girl, the 
daughter of a shepherd living at Kaplitz, in 
Bohemia, was in the habit of eating water- 
cresses, and drinking the stagnant water of 
ditches in the locality where she lived. After 
a while her health failed and her body became 
much enlarged. A medical man. Dr. Kichner, 
Fig 1 -Tailed lar three days before she died, and by a 
vhtrematode, or jpost-mo7'tem examination, he ascertained that 
no less than forty-seven specimens of a small 
A'lk® (Distoma lanceolatum, fig. 2),_ had taken 
X isodiam. up their residence in this inappropriate hostJ^ 
I say inappropriate ” because the parasite species in ques- 
tion has only three times been detected within the human 
host its proper habitation being, apparently, the liver of 
the ox and sheep. In addition to its accidental 
introduction into the human host, the Distoma 
lanceolatum strays occasionally into the bodies 
of pigs, deer, hares, and rabbits. The lowermost 
larval condition of this parasite is known to be 
a minute ciliated creature which swims about 
freely in the water ; but its higher larval form 
{Gercaria) , though certainly occupying the body 
of some mollusk, has not been clearly and pre- 
cisely indicated. 
The same kind of demonstration is yet want- 
^ ^ cfoar up the only remaining link which 
is wanting to complete the chain of evidence as 
regards the introduction of the common fluke {Fasciola 
liejpatica, fig. 3) into the human body, and 
into the liver of the sheep, giving rise in the 
latter to the formidable rot disease. JSTot a 
vestige of doubt exists that we and they — ^.e. 
ourselves and the sheep — alike obtain this para- 
site by swallowing the larvae of this entozoon 
along with vegetable matters. It may be, 
indeed, that the intermediate bearers are swal- 
lowed along with the water drunk, but it is 
much more probable that the mollusks are 
Fig. 3.— Common usually adherent to watercresses, grass, or other 
h1^atica)fnitmii Vegetable food. The details connected with 
their migrations, development, and transforma- 
tions, I have partly worked out and explained elsewhere, so 
that I am only now more immediately concerned to show that 
in the preparation of vegetable as of animal food, it is of 
Fig. 2. — Distoma 
