is, 4 Haughwout: Human Coccidiosis 457 
Kow and are much easier to pick up than in the usual slide 
emulsion. 
So far as I can learn from this case, there are no criteria 
other than the finding of the cysts that will enable a sure 
microscopical diagnosis of intestinal coccidiosis. The stool 
affords no constant characters other than the cysts, so far as 
I have seen, that will render it possible to make a presumptive 
or tentative diagnosis, as is possible in the case of the dysen- 
teries. If active symptoms should appear before cyst forma- 
tion begins, there would appear to be nothing to do except to 
wait until the cysts begin to appear in the fseces, as they will 
in due time. Porter ( 13 ) in writing on this subject says, how- 
ever, “The infective oocysts and sometimes epithelial cells 
containing trophozoites or schizonts are found in fseces and 
serve for diagnosis.” 1 cannot agree that the finding of infected 
cells in the fseces is sufficiently constant to be of much aid in 
microscopic diagnosis. At least that was not my experience with 
this case. 
In these infections the destruction of tissue by the parasite 
is limited to the epithelial cells of the intestine and it is not a 
necrotic process. It is conceivable that in extensive infections 
secondary bacterial invasion might occur and its products make 
their appearance in the stools, but such stools could scarcely be 
expected to be in any way characteristic of coccidiosis. It 
seems to me safe to say that in the general run of cases, pus 
and blood will not appear in stools. This, notwithstanding Noc 
has reported finding blood in the stool of his Dakur case. 
Mucus may be present and Noc, and Porter, as well as I have 
seen desquamated epithelial cells. Noc was fortunate enough 
to find one containing what would appear to have been a tropho- 
zoite of Isospora. I saw these epithelial cells on one occasion 
only; but, although I searched carefully, I found no intracellular 
parasites. 
Some day, some one may succeed in making recognizable 
stained preparations of coccidial cysts, but for the present I 
should advise the amateur not to waste his time trying to stain 
them, for he will not succeed by the usual methods. Indeed he 
may even have trouble in fixing them. Such observations as 
have been made on the cysts of the coccidia have been made on 
fresh material, and we have no real knowledge of the ^cytology 
of the organisms in this stage of their life cycle. 
Another thing that will trouble the inexperienced is the rather 
large number of unfertilized and otherwise abnormal cysts that 
will be found on study of a case. For this reason I have thought 
