weeks allowed for the trematodes to attain 
a size which makes them easy to see. With- 
out these conditions the research may give 
a negative result. 
In rodents the development of a consi- 
derable number of Sch. M. is quite compa- 
tible with all the signs ot good health. The 
worms are evidently well adapted to life in 
the blood-vessels and their consumption of 
blood is not sufficient to cause serious ane- 
mia. The symptoms are mostly due to the 
laying of the eggs and their migration which 
only begin after some weeks. 
In the excrements of infected guinea- 
pigs eggs were not found till after a period of 
2 and 1/2 months and then only in small num- 
bers. In the worst infection (in a rabbit) 
eggs were rate in the sub-mucosa and there 
were none voided; it may be that in man the 
conditions are different but, in the cases of 
rabbits and guinea-pigs, we may conclude 
that the elimination of eggs is a slow process 
and that it generally happens some time 
after the parasites have reached maturity. 
Some observations in human pathology 
and some of the experiments of LEIPER 
seem to indicate that the elimination of eggs 
took place rather sooner, five or six weeks 
after infection. I think the fresh cases must 
have been very heavity infected and that 
later on the eggs would have been more 
numerous. 
After three weeks adult worms are found 
in the mesenteric veins which are generally 
very congested. The veins of the liver con- 
tain about the same number. After five weeks 
the sexual organs are well developed; in the 
uterus the females show a ripe egg. The 
dimensions of the flukes vary considerably, 
according to the degree of muscular contrac- 
tion. The specimens which die slowly in the 
tissues of the host, are quite relaxed. But 
even so the dimensions are slightly inferior 
to those given in the old literature. 1 do not 
think that this is due to the difference of the 
hosts, as the worms, found in autopsies of 
infected people, were not distinctly larger, 
but perhaps the species Mansent may be 
smaller than the haematobium of which the 
LS cee 
females contain many eggs, instead of one 
only. The intestine of the female can be 
easily seen, as it is full of black matter, 
formed from the absorbed and digested 
blood. The same may be said of the male 
though in a lesser degree. In sections of the 
liver, the females, cut transversally, would 
be little conspicous, if they were not charac- 
terised by the intestinal lumen showing in 
One or two places, according to the region. 
Besides this, the sections of the excretory 
canals are seen. The male is more characte- 
ristic, due to its form and to the spines 
on its body. 
Symptomatology of Schistosomatosis. 
There are several methods for dete: mi- 
ning the symptoms of infection by Sch. Man- 
sont. We can study men (naturally) and ani- 
mals (experimentally) infected withthe dise- 
ase, verifying the objective symptoms and ta- 
king note of the complaints of the patients ; 
or we may begin with the macro-and micro- 
scopic anatomic alterations. Whe have another 
resource in the comparative study of the le- 
sions, produced by other species of Schisto- 
somum in men and domestic animals. The 
most important is the Schistosomum Japoni- 
cum producing very intense infections, as well 
in man, as in the larger domestic animals. 
They are generally located in the same or- 
gans and have been widely studied 9). 
The first observations on Schistosomum 
infections, made in the Old World, may be 
used but only with great caution, as the symp- 
toms belonging to two species of Sci. and 
other intestinal parasites are frequent in the 
same place. 
The presence of adult worms in the veins 
is mostly well borne (which agrees with 
the general rules of parasitism); it is pro- 
ved by the fact that a rabbit may have half a 
thousand worms in the mesenteric veins 
without showing any particular symptoms. 
On the other hand, LETULLE attributes 
the phlebitic processes, observed in cases of 
long standing, to the parasitism of the adult. 
Glands with toxic or irritating secretion 
are unknown in adult schistosoms, but cer- 
