<jr. H. F. Nuttall 
47 
ciated with the presence of lice upon the person attacked.” [Low 
gives no reference.] 
That the clothing of typhus patients is a source of infection, was 
soon recognized. Lind (1833) 1 pointed out the high incidence of 
typhus among laundresses, and Perry (1836) 1 noted its spread through 
convalescents transferred to clean wards with the clothes they had 
worn when ill. 
Passing over older authors, we find that Hirsch (1881, vol. i, p. 405) 
points out the great similarity between the epidemiology of typhus 
and relapsing fever, the world-wide distribution of the two diseases, 
and the fact that in neither is any racial immunity observable. 
Of fundamental importance, however, is the work of Murchison 
(1884) on the epidemiology of typhus. There is practically nothing 
to add to-day to the epidemiology of the disease as outlined by this 
author, if we except the most recent discoveries regarding the part 
played by lice as vectors. Murchison found: (1) That when typhus 
appears in a locality or house, it usually spreads very fast. (2) That 
the number of cases stands in direct relation to the degree of contact 
between individuals. (3) That persons visiting the sick are prone to 
catch typhus. (4) That the sick convey the disease to clean quarters. 
(5) That typhus is checked by isolation of the affected. (6) That it 
is acquired by contact with the sick, by contact with objects contamina¬ 
ted by the sick, and by sojourning in places previously occupied by 
typhus cases. 
Murchison referred outbreaks to clothes “saturated with typhus 
poison.” He indicated the need of personal cleanliness, warm baths, 
change of garment, and the disinfection of clothing for those in attend¬ 
ance on the sick. The convalescent should receive the like treatment. 
Visitors should not sit on the beds occupied by the sick, and in hospitals 
“the same bed and bedding ought always to be reserved for typhus 
cases.” He considered that there was much evidence which proved 
the efficacy of these simple prophylactic measures. 
The period of incubation, under natural conditions, would appear 
to vary between 9 and 20 days. (Jacquot, in the Crimean war, recorded 
9-13 days; Barallier gives 12-15 days; Murchison gives 12 days, basing 
the figure on 31 cases observed by him in practice; Thoinot and 
Dubief (1893), in Paris, give the period as 10 or more days: Boral (1915) 
and other recent writers record an incubation period lasting 10 to 
20 days.) 
1 Cited by Murchison (1884). 
