MICROSCOPIC ORGANISMS IN INTESTINAL CANAL, 287 
and it may, therefore, be conveniently distinguished by the name 
of Protomyxomyces coprinarius. 
It has already been pointed out that the different develop- 
mental forms of the parasite exhibit a high degree of variability 
under the influence of variations in the external conditions to 
which they areexposed. Various forms of the zoospores are thus 
encountered, replacing one another in different media and in the 
same medium at different times. In some cases the flagellate 
zoospores show a distinct contractile vesicle and nucleolar point ; 
in others any differentiation of such structures seems to be want- 
ing. The degree and character of movement, the consistence, 
size, and outline of the body are also extremely inconstant ; and 
a similar variability, although perhaps to a somewhat slighter 
extent, prevails in the ameeboid stage. There is one very distinct 
form of the flagellate zoospores which in many respects is so un- 
like the common ones that it might readily be regarded as an 
indication of specific difference, were it not possible to observe 
its origin as a mere transition form. In this case the body is 
characterised by a peculiar spathulate flattened contour, and ex- 
hibits a peculiar type of movement, consisting in a hinge-like 
flexion of the posterior slender portion of the body on the an- 
terior broader part. In some specimens of choleraic excreta, as 
was previously pointed out,! this variety almost entirely replaces 
the normal one, but its occurrence is not limited to such media, 
as it has more than once been observed to arise in cultivations 
of cow dung. Variation in the size of the spores in the same 
or in different sporangia is a phenomenon of constant occur- 
rence, and one which runs through a wide range of develop- 
ment. As we have previously seen, moreover, there is some 
reason to believe that there are two distinct forms of spores, 
which may replace one another more or less completely under 
different circumstances, the commoner one being distinguished 
by its spherical or biconcave figure, the other by its smaller 
size, more or less fusiform outline, and well-marked nucleation. 
So far as I have been able to ascertain, the occurrence within 
the digestive canal of the human subject in this part of India of 
zoospores or ameeboid bodies belonging to any other develop- 
mental cycle than that which has been described above is very 
rare and quite exceptional. It is different, however, in the case 
of other animals in which the same parasitic forms occur. In 
many specimens of fresh vaccine excreta smaller numbers of 
various other organisms are also occasionally present. Some of 
these are unquestionably specifically distinct, and others, while 
not unequivocally so, still present certain characters requiring 
? *Seventh Annual Report of the Sanitary Commissioner with the Go. 
vernment of India,’ Appendix B, p: 189. 
