SEVENTH ANNUAL REPORT. 109 
cent work of Theobald Smith, who has conclusively shown that 
the disease may be communicated through infected meat. 
Since our attention was first drawn to this sarcosporidion we 
have systematically investigated the heart muscle of all the dead 
elk, and the result has been that we have been able to demon- 
strate the parasite in every case. Though the organism may 
exist in the heart muscle without strictly inflammatory changes 
in many cases, my studies have shown that in most cases where 
found in the heart, they give rise to a general parenchymatous 
degeneration of the muscle cells, this together with the destruc- 
tion of the individual infected fibres greatly impairs the heart 
action and eventually causes death. Doubtless this is the cause 
of the unsatisfactory condition of the elk, and probably nearly 
all the members of the present herd will eventually die with 
the disease. This condition is serious enough in itself, but the 
parasite has also been found in the myocardium of several cari- 
bou, producing the same results in these animals as in the elk. 
Mere gross examination of suspected tissues is not sufficient to 
establish the absence of the parasite, for I have been able to find 
it in microscopic preparations where it was not seen macro- 
scopically. 
Unfortunately the life history of this organism is not known, 
notwithstanding the very considerable researches which have 
been conducted in regard to it. It is, however, generally ad- 
mitted to be communicable, though the manner of infection is 
quite unknown, that is among the ruminants, for Smith has 
shown us that infected meat is capable of producing the disease 
in susceptible animals fed upon it. Reasoning from analogy we 
may probably safely infer that the disease is also communicated 
among the ruminants by the intestinal tract. The origin of the 
infection is obviously a matter of considerable importance to us. 
It is highly improbable that the parasite exists in the muscle of 
the wild animal. In my own somewhat limited observations of 
the musculature of dead wild animals of this class I have never 
seen it. Diligent inquiry among hunters and guides has also 
failed to give me any data of at all “probable” cases, so the 
disease is most likely acquired in captivity, and probably by in- 
testinal infection with the dejecta of diseased animals. The 
parasite is very frequent in the common sheep, and Kuhne has 
found it in 98.5 per cent. of pigs examined (in Germany). It 
is more than probable that the present ranges of the Park have 
previously been utilized for pasturage for sheep and pigs. 
Granting, then, that the sporidion is communicable, we have a 
