28 
THE COLORADO EXPERIMENT STATION 
are none of these germs that are constantly found by all. With the view of 
determining whether or not the type of roup existing in Colorado is due to 
an ultramicroscopic germ, two diseased hens were secured through the aid 
of Mr. Vaplon. These birds had swollen eyes, with an accumulation of 
catarrhal product in the maxillary sinuses (the bulging observed below and 
in front of the eye) and a discharge from the nostrils of an offensive odor. 
There were also characteristic yellowish-white diphtheritic patches in the 
mouth. Material from all these lesions from both birds was prepared in 
physiological salt solution (.8 5 per cent common table salt) and filtered 
through a Pasteur filter calculated to take out all germs that can be seen by 
aid of the microscope or that could be produced in visible growth upon artifi¬ 
cial culture media. The fluid that passed through this filter was used in in¬ 
oculating experimental birds. These birds were from flocks in which roup 
had not appeared. In all, fifteen inoculations were made. Tubes of media 
were inoculated with the filtrate and no visible growth of germs was seen 
after being incubated at 3 7 degrees C. for 72 hours. 
Observations were continued on the inoculated birds for thirty days and 
roup did not appear in any of them. So far as this one experiment goes, it 
does not indicate that our type of roup is due to a filterable virus. 
MODE OF SPREAD.—The disease is spread by the introduction of birds 
from infected premises, and by exposure of birds at poultry shows to the con¬ 
tagion. A chronic type of the disease in some birds of the flock may serve to 
infect others, when they are weakened by predisposing causes, as by exposure 
to cold, damp roosting places, drafts and badly ventilated buildings. 
SYMPTOMS.—There are three forms of the disease. In the nasal form 
there it at first a thin watery discharge from the nostrils, with an offensive 
odor which is characteristic of roup. Later the catarrhal product becomes 
somewhat thicker and the nostrils become glued shut, and quite frequently 
there is a bulging of the maxillary sinus below and in front of the eye. This 
is due to an accumulation of the inflammatory products in this sinus, or cav¬ 
ity. Figure 2 7 illustrates this common swelling. The second part affected is 
the mouth. This affection often accompanies the nasal form. Figure 28 
illustrates these diphtheritic ulcerations, which are covered with a yellowish- 
Fig. 27 1 
, Figure 27.—Hen afflicted with roup; a shows the swelling- the eve is" swollen 
shut and the sinus beneath and in front of the eye is bulging as a result of the 
secretions from the inflammation caused by the germ of the disease The .mucous 
membrane surrounding the anterior portion of the eye ball is greatly inflamed 
(conjunctivitis) and is filled with a mucopurulent material S Y in. 
