32 
informed by him that in said locality the people had never experienced 
“spotted fever” and did not fear it. 
Whether or not the absence, or at least the apparent absence, of 
spotted fever from this restricted area between Carlton and Lo Lo is 
connected with the more advanced condition, as found also on the east 
side, is one of the points to which future investigation should be 
directed. 
It will be noticed that while Wilson and Chowning (1902a, 1903a, 
1901a) and Anderson (1903a, 1903c) speak of the east side of the Bit- 
ter Root Valley as the uninfected localit}^ and the west side as the 
infected locality, other statements Wilson and Chowning make lay 
stress upon the fact that infection is more or less limited to the foot- 
hills on the west side. Maxey also mentions especially the foothills 
in Idaho. 
To Ashburn and to me these references to the foothills seemed to 
be of no little importance, and they were rather strong!}" confirmed 
by our inquiries, for we found the general opinion to be that it was 
chiefly in the foothills that infection took place. This indicated that 
the infectious area, or at least the area of more intense infection, 
was bounded on the east, not by the Bitter Root River, but by the 
“bench,” or foothills, and as a matter of fact the local physicians and 
inhabitants seemed quite generally to be under the impression that 
the narrow lowlands close to the river were comparatively, if not 
entirely, safe so far as infection was concerned. 
CoMPAKisoN. — As shown on page 29, this tendency to limitation of infection in the 
foothills of mountains does not seem to agree with piroplasmosis in cattle, sheep, 
and dogs. 
SEASONAL DISTRIBUTION. 
Practically all authors lay stress upon the fact that the afi'ection 
under discussion is preeminently a disease of the spring months, but it 
might be well to direct attention to the fact that any given date (as 
April 15) in the localities in question does not necessarily correspond 
in season to the same date in localities in the Southern or Eastern 
States. 
Idaho . — Bowers (1896, p. 63) says that “spotted fever” occurs only during the 
spring, from about the 1st of March to the middle of May. According to Collister 
(1896, pp. 62-63) it appears in March and continues until the latter part of June. 
After Fairchild (1896) it usually prevails from April 1 to July 1. Maxey (1899, p. 
434) reports that it invariably occurs during the spring months. The Medical Sen- 
tinel (1899, p. 457) says that “the greater prevalence of this fever in the spring sug- 
gests that the infection enters the system more easily at this time, or that the morbific 
agent is to be found in greater profusion. Reasoning on grounds of analogy it would 
seem that the former is the more likely explanation. No doubt stockmen, herders, 
and others living in these high altitudes have their powers of resistance considerably 
lessened by the rigors of a long winter; exposure to cold and deprivation of certain 
articles of diet producing a condition approaching scurvy. Naturally, then, we would 
expect in a weakened system an exhibition of virulence from the first pathogenic 
