148 



POULTRY DISEASES AND THEIR TREATMENT. 



cheese and sometimes to cat's urine or to macerating animal ma- 

 terial. In early stages the general health does not appear to be 

 afifected but as the disease advances the bird loses its appetite, 

 becomes poor and exhausted, and finally dies. 



Etiology. The disease is caused by the fungus Achorion 

 schonleinii- 



Fig. 38. The fungus Achorion schon- 

 leinii which causes favus in poultry, 

 tv. — Empty tubes of mycelium, 

 tp. — Tubes of the mycelium con- 

 taining protoplasm and spores. 



This fungus is found in the cup like scales on the skin and in 

 the quills of the feathers of the diseased parts. If the f avic cups 

 or scales are moistened with weak acetic acid and examined un- 

 der the microscope it will be seen that they are formed of 

 branching, thread-like mycelial tubes of the fungus closely 

 interwoven with one another, spores of the fungus, and epithelial 

 scales from the skin of the host imbedded in a viscid substance 

 secreted by the fungus. Some of the tubes of the mycelium 

 contain spores. Many of the spores are found free among the 

 filaments. They are usually found in groups of 3, 4 or 8. 



Both the mycelium and spores of the fungus are found in the 

 quills of the feathers of the diseased parts. The fungus some- 

 time's penetrates even the barbs of the feathers. 



Favus is a contagious disease and gets into a flock by the in- 



