18 
are to his mind convincing. McCullough (1902, p. 225) refers to the locality as hav- 
ing a “bearing upon this deplorable affliction with suitable environments, most cases 
giving a history of exposure to wet and cold, or violent physical exercise and over- 
exertion.” 
Wilson and Chowning (1902a, 1903a, 190-ta) were the first authors to describe a 
specific organism as cause of the disease. They call special attention to the fact that 
their bacteriologic cultures failed to show any bacteria of etiologic significance, and 
they describe bodies which they interpret as protozoa and which they later name 
Pyroplasma hominis^^ [namely Piroplasma liominis]. The secretary of the Montana 
State board of health (see report, issued 1903, p. 25) says that the cause has been 
“attributed to various sources, particularly the water, mineral, and general condi- 
tions of the soil, and by some thought to be contained in the snow of the Bitter 
Root Mountains, as well as various and varied local conditions.” 
The only definite proposition as to a specific cause is that advanced 
b}" Wilson and Chowning (1902a, c, 1903a, 1901a), naiiieh^ that 
“ spotted fever” is due to a protozoon parasite which lives in the red 
blood corpuscles; this protozoon they classify (1901a) as a member of 
the genus Piroj)lasma. 
The genus Piroplasma^ which is very possibly identical with Bahesia^ 
seems very clearl}^ to be a protozoon, but its more exact systematic 
position is at present somewhat uncertain. It is one of the most 
difficult of all the protozoa to interpret, and little is known of its life 
cycle. Its synon^mw is as follows: 
Genus PIROPLASMA Patton, 1895. 
1888. ? Hsematococcus Babes [not Agardh, 1828]. 
1893. Pyrosoma Smith and Kilborxe [not Pyrosoma Peron, 1804], type species, P. i 
bigeminum of Texas fever. 
1893. ? Babesia Starcovici, 1893, July 1, type Babesia bovis (of bovine hemoglobi- 
nuria), whose identity with P. bigeminum is not fully established. 
1895. Apiosoma Waxdolleck [not Apiosoma Blanchard, 1885], equals Pyrosoma 
Smith and Kilborne, 1893, renamed, hence type species P. bigeminum. 
1895. Piroplasma Patton, equals Pyrosoma Smith and Kilborne, 1893, renamed, hence 
type species P. bigeminum. 
1904. Pyroplasma Wilson and Chowning, for Piroplasma. 
In view of the comparatively slight knowledge of the present day 
relative to the structure and life cycle of the members of this genus, 
hence the uncertainty as to whether Babesia bovis is really congeneric 
with Piroplasma bigeminum^ I retain the name Piropilasma in this 
discussion. Should it be demonstrated that P. bigeminum and B. bovis 
are congeneric it will of course be necessary to reject the name Piro- 
p>lasma in favor of Babesia. 
In the genus Piroplasma several species are at present known as 
cause of serious diseases. Thus: 
Piroplasma bigeminum (Smith and Kilborne, 1893) is the cause of Texas fever of 
cattle. 
Babesia bovis, which maybe generically identical with, but specifically distinct from, 
P. bigeminum, is accepted as the cause of hemoglobinuria in cattle. 
