11 
was classified in one of the most diflicult groups, from a standpoint of 
interpretation, I had upon starting little hope that much could be 
accomplished in one season; in fact, I viewed the trip as the beginning 
of an investigation which would probably occupy the spring months 
for a number of }^ears to come. 
From the literature which had appeared upon this malady, especially 
from the last article by Wilson and Chowning (1901a), I had become 
somewhat prejudiced in faA^or of the protozoan theory relative to the 
origin of this disease, and also in favor of the theory that it was trans- 
mitted to man by ticks belonging to the genus Dermacentor ; regarding 
the h}^pothesis of its origin in the burrowing squirrel, however, I 
must confess that a priori reasons made me veiy skeptical. 
During my sta}^ in the Bitter Root Valle}" I was able to see 10 
patients who 1 was assured by local physicians presented typical cases 
of the disease. In 9 of these cases I was able to search in the fresh 
blood for the parasite. Part of my time was occupied in studying the 
ticks, the burrowing squirrels, the topography of the region, and other 
points to be considered in connection with the malady. 
Acknowledgments. 
I am under numerous obligations to various persons, especially the 
local physicians in the valley, for many courtesies extended to me 
during my investigations. Among these I would mention the follow- 
ing in particular: 
To Dr. John Jay Buckley, who for years past has spent much time and money 
in studying “spotted fever,” I am under special obligations for the courtesies of his 
private laboratory and library, as well as for giving me so much time in showing me 
through the valley, taking me to see patients, and for other courtesies too numerous 
to mention. 
To Dr. Percy M. Ashburn, captain and assistant surgeon, XT. S. Army, stationed 
at Fort Missoula, I am under many obligations for use of his laboratory and his 
instruments, for accompanying me on various trips through the valley, and for 
his association in studying the cases. Doctor Ashburn had commenced to study 
“spotted fever,” under instructions from Surgeon-General BobertM. O’Beilly, V. S. 
Army, before I reached Missoula. After my arrival we worked together, yet inde- 
pendently, constantly checking and criticising each other’s work. Our final conclu- 
sions were practically identical in all important respects. 
To Maj. Z. W. Torrey, in command of Fort Missoula, I am indebted for many 
official courtesies, including the use of post transportation facilities upon several hard 
trips through the mountains. 
To Dr. Edward W. Spottswood, chief surgeon of the Northern Pacific Eailroad 
Hospital at Missoula, I am indebted for the use of his laboratory and laboratory sup- 
plies, as well as for valuable advice. 
To President Oscar J. Craig and Prof. M. J. Elrod, of the State University, I am 
indebted for the use of the university laboratories and supplies. Professor Elrod 
also kindly took photographs of patients at my request and accompanied me on col- 
lecting trips. 
To Dr. William Park Mills, Dr. Charles H. Pixley, Dr. Russell Gwinn, Dr. Samuel 
W. Minshall, Dr. George Hampton Putney, Dr. William B. Parsons, Dr. John T. 
Brown, Dr. Thomas A. Fitzgerald, Dr. George T. McCullough, Dr. Watkins, Dr. 
