140 DISEASES OF DOMESTICATED BIRDS: 
sult in the infection of the Malpighian secretion and excrement with 
coccoid bodies. 
While the salivary gland has been considered with reference to the 
part played by saliva in introducing infection into fowls, the obser- 
vations tend to show that contamination of the tick-bite wound by 
coccoid bodies in excrement and coxal fluid, is responsible. 
Coccoid bodies are capable of development into the typical spiro- 
chete by a process of gradual lengthening. This has been observed 
in the ticks but not in the blood of a fowl. 
The eggs of an infected tick contain coccoid bodies and the progeny 
of such a tick is infective either by feeding on a fowl or when in- 
gested by a fowl. 
Ticks after feeding on infected blood are most liable to be in- 
fective when kept at a temperature of 30-35° C. When ticks are 
kept at 15-18° C., the spirochetes disappear from the alimentary 
tract, and such ticks do not transmit the infection. 
Differential diagnosis. The various septicemias of fowls, more 
particularly fowl cholera, might readily cause symptoms and lesions 
simulating spirochetosis. Microscopic examination of stained blood 
smears should furnish conclusive evidence by showing whether the 
septicemia is caused by spirochetes or by bacteria. The limited 
area of the United States in which ticks occur, see p. 221, should be 
borne in mind. 
Treatment. Dodd reports that 4% grain of soamin dissolved in 
one c.c. of sterile water and injected intramuscularly, modified and 
shortened the attacks with rapid and complete recovery. Uhlen- 
huth gave atoxyl in an average dose of 5 centigrams at the time of 
infection or two days later. It prevented infection or cured but 
the blood remained infective. 
Hauer concludes that salvarsan is capable of destroying spirochetes 
in the body. The curative action of this substance is established 
in all cases on the day of treatment and acts in a remarkable manner 
even after the use of a limited amount of salvarsan. Even in cases 
where the treatment was first given on the fourth day after infection, 
when the bird was somnolent and when the blood was swarming with 
spirochetes, one injection of the agent in not too small a dose led to 
striking improvement and recovery. The immunity which salvarsan 
confers upon birds protected with it, is of high degree and of long 
duration. 
Hauer experimented on fowls with a wide variety of doses of 
the drug. The lowest lethal dose was found to be .3 gram and .15 
