108 DISEASES OF DOMESTICATED BIRDS 
pox lesions favored the increase of virulence of saprophytic hem- 
orrhagic septicemia organisms commonly present in the mouth. 
Jackley has worked on the bacteriology of roup, reaching the fol- 
lowing conclusions: 
“1, A bacterium, designated culture ‘33A,’ having all of the morpho- 
logical, cultural and biochemic characters of the pasteurella group, ap- 
parently deserves recognition as the etiological factor in roup. 
“9. The organism has been recognized by smears in all cases of roup 
examined. 
“3. It has been isolated and grown upon artificial culture media and 
the characteristic local lesions of the disease again reproduced. 
“4, Finally, an absolute protection has been shown against the natural 
disease after immunization with a pure culture bacterin of this organism.” 
Beach, Lother and Halpin isolated from roup lesions an organism 
probably belonging to the hemorrhagic septicemia group. Injection 
of killed culture was shown to produce immunity against injection 
with virulent culture. The organism was regarded as a secondary in- 
vader, as it did not produce lesions of roup or chicken pox. It was 
regarded as of importance as a secondary invader in wound infection. 
The identity in name and similarity of lesions of diphtheria in 
man and in birds has attracted attention to the possible relationship 
between the two diseases. There is no doubt that the two diseases 
are quite distinct in etiology even though rare cases of infection of 
birds with Bacterium diphtherie have been reported. 
SIMPLE CATARRH OR COLD 
This condition is a mild inflammation of the nasal passages and 
is common to all species of domesticated birds. It cannot be differ- 
entiated from the early stage of avian diphtheria. 
Etiology. No definite cause may be assigned to this affection. 
It has been asserted that weak or improperly nourished birds are 
more likely to be attacked than strong, vigorous, well nourished in- 
dividuals. Exposure to unfavorable conditions in which rain or 
dampness accompanied by cold draughts tend to so affect the mucous 
membranes of the nostrils that the various organisms which are nor- 
mally present in this region become pathogenic, has been held to be 
the primary contributing cause. 
Symptoms. The affected fowl is more or less dull in appearance, 
according to the severity of the attack. The appetite is diminished, 
breathing becomes difficult, and a watery discharge from one or both 
nostrils is early in aidlencs, This discharge may disappear in the 
