41 
and minimum time between exposure and onset can not be well 
established from the data now at our disposal. 
Arguing’ upon the tick hypothesis it would seem that the disease 
might develop within a day after exposure. 
Comparison. — Smith and Kilborne (1893, p. 15) point out that the term “period of 
incubation” is used in two different senses -in connection with Texas fever. In 
experimental cases of Texas fever it is 6 to 10 days after the cattle are inoculated 
with Texas fever blood, the time depending on the number of parasites originally 
introduced, the predisposition and age of the animals, and the season of the year. 
Starcovici gives about 14 days as incubation period for hemoglobinuria, and “about 
8 days (?)” for carceag. For canine piroplasmosis the period is given as 10 days 
from the date of visiting a tick belt (Robertson); Xuttall found it to be 13 to 21 
days in dogs bitten experimentally by ticks; upon subcutaneous injection the period 
varies from 3 to 10 days. 
Onset. 
Idaho . — During incubation there is a slight headache and a feeling of lassitude 
and inaptitude for work; during the first week following this period the patient 
complains of chilly feelings, nausea, loss of appetite, intense headache, pain in the 
back and legs, a muscular soreness and stiffness of the entire body, and he takes to 
bed with a temperature of 102° to 105° F., pulse 90 to 120 (Bowers, 1896, p. 63). 
According to Collister (1896, p. 63) many cases are taken suddenly without previous 
malaise, some with a severe chill and others with more or less chilly shudderings 
frequently referred to the spinal regions; still others have little or no chill. Dubois 
(1896, p. 64) says that there is usually no prodromal stage and a patient is stricken 
down without warning with severe frontal headache, photophobia, nausea, lassitude, 
persistent anorexia, and intensely severe pains in joints and muscles. According to 
Fairchild (1896, p. 62) the attack is sometimes ushered in by a chill, but usually by 
two or three days of malaise, with severe headache, particularly in the back part; 
also shooting pains throughout the body and limbs, usually more severe in the 
bowels and back; the pain is neuralgic in type. Figgins (1896, p. 64) states that the 
disease begins with a chill, pains in the extremities, muscular soreness, and fever, 
the temperature ranging from 100° to 105° F., pulse 100 to 120. Springer (1896, 
p. 61) says there is a feeling of malaise for a few days, followed by a chill; the fever 
then sets in, ranging from 103° to 105° F. According to Sweet (1896, p. 61) the 
onset is usually accompanied by severe break-bone pains. According to Zipf (1896, 
p. 65) the onset is suddeUj with high fever, violent headache, coated tongue, back- 
ache, and flushed face. Maxey (1899, p. 435) states that the patient first notices a 
general malaise, loss of appetite, and flashes of heat and cold, but no marked chill; 
the bones and muscles soon begin to ache, and by the second day the patient feels 
sick enough to take to his bed; he already feels very weak and depressed, and pains 
in the back, in the joints and muscles of the extremities, and in the head become 
quite severe; the bowels are constipated. 
Montana . — In a few cases the disease seems to be preceded by a prodromal period 
of malaise for a few days; the attack comes on by either a well-marked chill or chil- 
liness, simultaneous with fever, general aching and soreness of the entire body, and 
a flushed dusky red color of the skin. The chilliness, although most severe at the 
onset, often continues more or less throughout the attack, coming on at intervals — 
generally mornings — and becoming lighter day after day until within a week or so the 
chills seem but little more than chilliness from light covering (Gwinn, 1902) . 
According to McCullough (1902, p. 226), the onset may be marked by a sudden 
and severe chill and dizziness, with high fever following, associated with intense 
soreness seemingly of the entire muscles of the body, or it may come on insidiously. 
