DISEASES OF POULTRY. 



59 



or more in thickness, which bears upon its surface a 

 growth of the fungus. These membranous patches are 

 at first soft, but become firmer with age, and are yel- 

 lowish or greenish in color, resembling a fibrino -puru- 

 lent exudate. They adhere closely to the mucous 

 membrane which is there thickened and inflamed. 

 The air -sacs are sometimes obstructed by these 

 growths which may in time become caseous or even 

 calcareous. These changes may also be seen in the 

 intestines, the mesentery, the liver and in other organs. 



Fig. 10, — Aspergillus glaucus, 

 aa, mycelium, 66, spore bearing- 

 stalks; cc, supports of the spores; 

 /f, chains of spores; gg, bluish 

 green spores. 



Fig. 11. — Aspergillus fumigatus 

 with conidia bearers; an, fruit 

 heads in optical cross- section; 

 5, fruit heads seen from above. 



The membrane lining the air-passages may, also, 

 be found ulcerated, and the ulcers may be either naked 

 or covered with a growth of the fungus. There is 

 often seen in the mouth of pigeons a whitish nodule, 

 the size of a pea or larger, which is called a canker. 

 This is believed by some authorities to be caused by 

 the aspergillus. 



In the very acute and rapid cases, the lungs may 

 simply show inflammation, or there may be formation 

 of pus or abscesses in the lungs, kidneys, liver and 

 spleen as in pyaemia or septic infection. In some of 



