ROT IN SHEEP. 
279 
or Penie-grass; it wil comonly grow in moist and marrish 
grounds, and it groweth low bv the ground, and hath a 
leafe on both sides of the stalke like unto a penie, thick 
and round, and without floure, yet some doe saie it beareth a 
yealow floure, which will (as they say) kil sheepe if they eat 
it. Alsoe all manner of Grasse that landfloods doe overrun 
before a raine is not good for sheepe.” Coming down to later 
times, we have had a theory which certainly ought not to be 
rejected without due consideration. It is founded entirely 
upon the existence of the fact that in this disease certain 
entozoa, to which I shall allude more fully, are inhabiting 
the biliary ducts of the liver; that these entozoa produce a 
number of eggs, which pass out of the liver into the intes¬ 
tines, and are consequently expelled with the feculent matter 
of the sheep, in countless myriads it may be said. Some time 
ago, a Mr. King (I do not know whether he had a medical 
education or not) wrote a series of papers in the 6 Bath Society's 
Journal/ in which he propounded the theory that the rot in 
sheep was due to this circumstance : that healthy sheep, if put 
upon pasture grounds w here these eggs exist upon the soil, 
receive them into their organisms; that the eggs produce the 
flukes, and that the flukes w T ould consequently thus find their 
proper habitat —that they w 7 ould seek out instinctively the 
biliary ducts of the liver, w here they would locate themselves 
and grow to perfection. This theory of the simple introduction 
of fluke eggs certainly did seem to have common sense for 
its foundation ; but it was found, after a certain length of 
time, that there was little or no truth even in it; that the ova, 
for instance, of fluke eggs did not immediately produce flukes. 
Some ten years ago I put this to the test of positive experi¬ 
ment. I collected a great number of the eggs of the fluke— 
far more than it wmuld be possible for a sheep to receive into 
its stomach even in the course of a summer’s grazing. I took 
no less than a teaspoonful of them, and it w 7 ould be scarcely 
possible for you to count the number in a single drop of water 
in which they are placed under the field of the microscope; 
and these, therefore, to the number of millions, I conveyed 
into the system of a sheep, which I kept six months, and then 
had it destroyed. On examining its liver and other organs I 
found that there w r ere no entozoa in the biliary ducts. In 
reality, there was not a single fluke produced from those mil¬ 
lions of eggs so carried into the system of the animal. This 
negative result was exceedingly valuable, and I may further 
remark that it fully confirms similar experiments carried out in 
Germany. Gerlach, w 7 ho is connected with the Berlin school, I 
believe, has had recourse to experiments of the same kind, and 
