i85 
the close company of others ; the water itself may perhaps be quickly 
flowing, thus sweeping the miracidia away from the place where they 
have been hatched, &c., &c. Under all these conditions, combined 
with tlie short time the miracidia are able to remain alive in water, 
the chances of entering the skin of a new human host are 
considerably reduced for any which may be in the water. Many a 
time not one will succeed in finding him and entering his body. On 
a single occasion, however, a few miracidia manage to enter his skin, 
and one gets safely to the liver. It produces males (we know that 
these are much commoner than the females; the probability of 
picking up a male sporocyst is therefore greater). The worms grow 
to sexual maturity, but finding no females they wait perhaps for a 
certain time, and then undertake the journey to the pelvic organs 
alone. After some time, the liver is again free from worms; the 
infection, although it has taken place, remains without consequences. 
The man continues exposing himself to the conditions for 
infection as indicated. What happened previously may be repeated 
at intervals, but on one of these occasions a miracidium may enter 
his body which produces female worms. These in due time begin to 
lay lateral-spined eggs. The oviposition goes on. perhaps, for a long 
time. The number of lateral-spined eggs increases steadily; all are 
carried to the liver. It is possible (I might say probable) that some of 
the females try to undertake their journey alone, but owing to their 
inferior muscular strength they may sooner or later be driven into 
some smaller side branch of the mesenterial, chiefiy of the splenic 
and inferior mesenteric veins. Not one succeeds in making the entire 
long journey to the rectum and the bladder. Of the specimens t lat 
have left the chief track leading to these organs, one or the other may 
reach the wall of the large bowel, filling a small area with her latera - 
spined eggs. At the end there will be a comparatively strong infection 
of the liver, and perhaps some isolated infected patches in the wall o 
the intestine, but no terminal-spined ova will ever appear, nor wi 
there be a regular infection of the bladder. After some time t e 
lateral-spined eggs of the liver begin to appear in the faeces, and 
they continue being voided in this way for several years. av 
further above (p. 174) hinted at the possible existence of 
which even the most careful post mortem examination would not 
detect any terminal-spined ovum in any organ; we here av e 
