AVIAN DIPHTHERIA AND BIRD POX 101 
indifferent to its mates, surroundings, or to a person’s approach. 
The head feels warm to the touch and there may be a rise of tem- 
perature. Diarrhea is often present. Death may result within 
two or three days in severe outbreaks or the bird may linger for a 
week or more with progressively increasing debility and more 
marked lesions. The head in many cases shows a pronounced swel- 
ling on one or both sides below and in front of the eye due to the 
accumulation of a cheesy mass within the suborbital sinus. Sneez- 
ing, which has been apparent in the early stages, gives way to a 
whistling or rattling in the throat. The inflammation in the nos- 
trils may spread to the mouth and pharynx, or even to the larynx 
and trachea, where exudates are formed which are principally of the 
croupous type. Breathing is entirely carried on through the mouth 
and the continual passage of air over the tongue tends to dry the 
tip with the result that its surface becomes hard and contracted. 
This condition is commonly termed “ Pip” and may occur in any 
affection which closes the nostrils, and compels breathing through 
the mouth. Death may be caused by dyspnea from the presence of 
massive accumulations in or upon the larynx, from toxins absorbed 
from the primary causative agents and secondary invading organ- 
isms, or from starvation, owing to inappetence, or the failure to dis- 
cover food in blind cases. No doubt the combination of causes act- 
ing together are responsible for the heavy mortality, amounting to 
90 per cent in some instances, among young birds. Before death, 
the subject becomes emaciated, sleepy, and finally unconscious for 
a period of several hours. 
Mild cases show less marked disturbances and may go on exhibit- 
ing symptoms for several weeks, finally apparently recovering their 
normal condition. Certain individuals retain the disease in a 
chronic state and serve as carriers for future outbreaks. 
Oftentimes the bird shows no external manifestations of illness. 
The comb and wattles have a deep red appearance and the hen con- 
tinues to lay. She dies quite suddenly and, on examination, the 
only lesion apparent is the formation of a false membrane on the 
border of the larynx or just inside that organ. This exudate has 
occluded the air- passage and caused death by suffocation. Fre- 
quently the condition i is discovered in time to save the fowl through 
the owner’s attention being attracted by a peculiar noise which ac- 
companies the effort of the bird to breathe. It will be observed to 
open its mouth widely and attempt to dislodge the exudate by a spas- 
modic movement of the respiratory apparatus. The resulting ef- 
