Gr. H. F. Nuttall 
63 
1913) are practically identical, although the latter (pp. 17-19, 29) 
gives some details not contained in the former. They cite the work 
of previous authors, and dismiss it as inconclusive. They express 
doubts as to the accuracy of Mackie’s statement that spirochaetes 
multiply in lice, this being contrary to what others have since observed. 
Sergent and Foley excluded other carriers than lice in connection with 
the Algerian epidemic they studied. In two experiments, they succeeded 
in producing infection with lice crushed 5-8 days after an infective 
feed of blood. Smith also succeeded in one experiment made with 
crushed lice. The authors cite Lemaire (no reference given) as having 
tried to infect a monkey by inoculation with two crushed lice and by 
the bites of infected lice. 
Nicolle, Blaizot and Conseil point out that previous investigators 
lacked two valuable methods in the study of the problem: (1) they did 
not use the ultra-microscope for the easy detection and observation of 
spirochaetes , and (2) they did not know the methods of raising lice 
under experimental conditions. With these aids, the authors determined 
that the spirochaetes become less motile already a few minutes after 
they enter the gut of the louse; in 1-2 hours their movement ceases; 
the spirochaetes then begin to degenerate, and all trace of them within 
the louse vanishes after 24 hours. They reappear, however, on the 
eighth, but more usually on the twelfth day, the number per louse 
being estimated at 10,000 to 20,000. The spirochaetes are now very 
active. At first they are thin and short, later they attain the normal 
size they possess when multiplying in human blood. 
Sergent, Foley and Yialatte (3. in. 1914, pp. 964-965) note that 
typhus and relapsing fever epidemics may occur together. We have 
already referred to this as an old and oft repeated experience. The 
authors, however, record an interesting observation wherein they acci¬ 
dentally transmitted typhus fever to a man and a monkey with the offspring 
of lice which it had been assumed were only infected with relapsing fever. 
Sergent and Foley (21. in. 1914, pp. 471-472) describe an experi¬ 
ment wherein lice were removed from a man on the fifth day of his 
first attack of relapsing fever; the lice, after starving for six days, 
were crushed in normal salt solution and the infective fluid was dropped 
into the nose of a monkey with positive result, the monkey suffering 
from a single attack. 
Sergent and Foley (6. vii. 1914, pp. 119-122) note an earlier obser¬ 
vation of theirs which showed that the blood of convalescents is virulent 
during the first apyrexial period although it contains no microscopically 
