1893, seen a good many of them ; a fact which struck me from the 
beginning was their very d i ff e r e n t size. In certain cases, they 
presented about their normal dimensions; in others, they were 
markedly smaller, and in some, they hardly reached a third of their 
normal length. Another fact which sometimes very forcibly 
obtruded itself to the eye was that the specimens present in an 
individual case were, among themselves, of very much the 
same size, i.e., of about the same age. I still 
possess in my collection the material from one case, which consists, 
after specimens have been given away, and others have been used for 
examination, of 62 males, all varying in length from 3 to 4 mm. 
according to their somewhat different state of contraction. There 
are, in addition, females (though in fragments only) which must have 
measured from 5 to 6 mm. so far as their length is still determinable. 
I also remember another case in which the worms m ales alone 
- presented two different sizes so distinctly that it was not difficult 
to separate them into two lots, each, of specimens about equal m size. 
On microscopical examination, all specimens proved to be sexually 
immature, and the degree of sexual development coincided about 
with their size. In many cases males were present alone; 
where both males and females were found they were still isolated, 
only in some two or three cases could a coupled pair be detected in 
the portal veins. The more advanced-females contained one or a 
few ova in their uteri, all of them of the lateral- spined type, 
some of quite unusual shape. These observations only confirmed 
what had been seen and described by some former writers. 
As a helminthologist I have not limited my investigations to the 
parasites of man. but have carefully and through many years, studied 
-anatomically and biologically—the Trematodes parasitic m animals. 
One result of these studies was that, very generally, Trematodes at the 
approach of their sexual maturity were found to form abnormally 
shaped eggs. In some most interesting instances the female 
genital apparatus was, owing to some malformation, found completely 
shut off from the male apparatus; there was no possibility for the 
egg-cells to become fertilized, but, nevertheless, the uterus was filled 
(in one case packed) with ova, all misshapen. In younger 
hut normal specimens of the same species, the uterus contained more 
or less numerous normal eggs, but in front, there were, sometimes a 
