Judging by the results of his investigations, the
writer concludes that:
1. Infectious Coryza of the fowl is a specific disease
caused by a filterable agent which was successfully
passed through the pores of the Berkefeld V and N
candles, the Chamberland L3 and L5 candles and through
the pores of the sterilising pad of the Seitz filter.
About 72% of the subjects inoculated with the bacteria -
free filtrate exhibited symptoms of Coryza.
2. In certain cases, a haemophilic organism can be
isolated from the various lesions of infected fowls.
This organism differs in virulence and growth requirements
from B. haemoglobinophilus coryzae gallinarum
(De Blieck) , H. gallinarum (the American group of
workers) and H. coryzae (Kessen and Van Dorsen),
which organisms were said to be the cause of fowl
Due to its dependence upon the V- factor only
for its growth, its inability to produce haemolysin
on blood medium, and on account of its failure to
produce indole and its restricted range of fermentation
of sugars, especially Saccharose, this organism
may be considered to belong to the para- influenza
group (Tapley and Wilson).
3. In rare cases, an avirulent bi-polar staining organism
is met with in lesions of Coryza in the fowl.
4. Intra -nasal inoculation of suspension of the various
bacteria isolated from the virulent exudate,
does not produce any harmful effects in healthy
chickens; thus indicating their insignificant importance
in relation to the disease.
5. The causal agent of the disease is found to lose
its virulence if left in the cage at room temperature
for 18 hours, whereas it is observed to retain
its pathogenicity for 17 days if kept at ice -box
temperature. Incubation for 10 hours at 37°C. renders the virulent exudate harmless to susceptible
birds. Heating at 60°C. for 5 minutes does not affect
the virulence of the exudate. This material is
found infective after its exposure to the action of
5% solution of carbolic acid, and to the action of
1/2000 solution of potassium permanganate for 2
hours. Inoculation of the virulent exudate after
being preserved for 12 days in 50% Glycerin at
ice -box temperature, requires a long period of incubation
before it can set up the disease in the
6. The disease exists only in one form, the incubation
period of which is influenced by the indivual
susceptibility of the subjects and the route
7. Young chickens and turkeys are the only birds susceptible
to the disease. Recovered subjects may
retain their susceptibility for another infection
of the disease in their early life.
8. Transmission of the disease is easily accomplished
by direct contact with infected birds, by ingestion,
and by intra-conjunctival, intra- auditory and intratracheal