468 The Philippine Journal of Science 1921 
Of course, infection experiments, only, would prove that the 
fully developed cysts I observed were actually living and capable 
of infecting a new host; but the sporozoites bore every evidence 
from their color and general appearance of being alive. 
A series of experiments designed to establish the resistance 
of the cysts to various chemical agents was also undertaken, 
but the results so far secured are not altogether satisfactory. 
For that reason a report on them will be deferred to a later 
paper. I am inclined to suspect, however, that the cysts of 
Isospora hominis are not so resistant as those of J. bigemina. 
EPIDEMIOLOGICAL CONSIDERATIONS 
The epidemiology of human coccidiosis offers the subject of a 
rather interesting study. It is a study, however, that is fraught 
with not a little difficulty to the microscopist who is unfa- 
miliar with the sporozoa. It is true that the present geograph- 
ical distribution of the coccidia of man rather closely coin- 
cides with the geographical distribution of experienced proto- 
zodlogists, but there is the not less-striking fact that a large 
proportion of the cases so far reported can be more or less 
directly traced to one source—the eastern Mediterranean area, 
Mesopotamia, or the Balkans. In fact, out of the cases shown 
on the map accompanying this paper only four, Noc’s Saigon 
case (the identity of the parasite here is not established), the 
two cases found by Miss Porter in Johannesburg, and Snijders’ 
Sumatra case, appear to be untraceable. Moreover, while there 
have been changes in personnel in the different laboratories 
where large numbers of stools are examined, protozodlogists 
have been pretty well scattered about the world for years. War 
conditions will account for the discoveries of the early cases, 
but they do not account for the later detections. 
Dobell(3) has thoroughly reviewed the situation up to 1919, 
so it is unnecessary to repeat the statistics he has given and the 
illuminating comment he has made. The principal findings are : 
plotted on the map. Dobell(5) also has disposed of two fictitious 
eases of human coccidiosis, so they need not be considered here.* 
For the purpose of tracing the case reported in this paper, 
however, it is necessary to recall that Brumpt has stated that 
the French armies were infected with Eimeria to the extent of 
0.2 to 0.33 per cent. Nothing, however, is said about Isospora 
*I refer to the cases reported by Huetter and by Lockhart Mummery 
and Gabriel. ' 
