not think it unreasonable to conceive that the venous blood coming 
from the bladder is chemically slightly different from that of tk 
rectal veins, and that this difference, slight as it may be, exercises an 
attractive influence on the \\ orJiis, thus ‘ leading ’ tiieni to the bladder. 
It is in this connection certainly not without significance that the 
whole journey goes against the blood stream, just as the dog 
scents the game against the win<l, but not with the wind At any 
rate, the veins of the bladder seem to be those first sought by the 
worms, although the rectal veins arc nearer and would serve their 
purpose (to bring the eggs to some place where they can easily reach 
the outer world) equally well. A.s a matter of fact, the other 
Schislosovia species known arc chiefly inhabitants of the intestma! 
veins. In Sch. Juonalobiitiu the first infection of previously healthy 
persons seems to normally concern the bladder, wliereas (apparently) 
the rectum becomes implicated after repeated infections only. Onf 
might almost imagine that after numerous eggs have been deposited 
in the bladder, and the normal function of the organ has become more 
or less impaired, tlie blood loses for the worms its peculiar ‘scent.' 
There may also be mechanical reasons which keep them in the rectal 
\eins in larger numbers than before, In this, or some similar 
way, the rectum would gradually become infected after the bladder. 
However. I do not find any reasonable objection either, to the assunip 
tion that ]ii some cases some couples of worms might from the 
beginning remain and establish tliemselvcs in tlie veins of the rectum 
Owing to the kindness of Dr. Ferguson. I have recently had the 
opportunity of examining several cases of 'early Hilharziosis of the 
a der, in which the most scrupulous insjicction of the rectum could 
not detect any visible change in tlie normal aspect of that orgaa 
Aevertheless. quite a number of (terminal-spined) eggs xvere found 
m the residue after a part of the rectal wall had been macerated in 
caustic potash. 
-It rectum) the real oviposition begins; the eggs ai 
at first scarce, but gradually increase in number. They are laid i 
‘Afterwards escape into the tissues and at 
finaHy voided from the body after having traversed the niucon 
lortTt" r, do not yet know he 
end of “‘^‘^oniplish tiiis journey, but some will reach th 
.t in a comparatively short time, whereas others may no 
