DISEASES OF POULTRY. 



141 





1. January. 



2. Middle of February. 



3. Befjinningr of March. 



4. Latter end of March. 



liquid in contact with the everted orifice of the ovi - 

 duct of the female. In some waterfowls which copu- 

 late in water, provision is made for a more efficient 

 coitus by the development of a long intromittent organ 

 from the highly vascular wall of the cloaca. This is 

 seen particularly in the 

 drake. In the passive 

 state this organ is coiled 

 up like a screw by the elas - 

 ticity of associated liga- 

 mentous structures. 



HYPERTROPHY OR EN- 

 LARGEMENT OF THE 

 TESTICLES. 



The testicles of birds 

 vary greatly in size ac- 

 cording to the season of 

 the year at which they are 

 observed. In winter they 

 are very small with a 

 comparatively insignifi- 

 cant blood supply, but in 

 spring, as the breeding 

 season comes on, they en- 



, f~ . . F iff. 32. — Testes of the House-spar- 



large to five or ten times row. 



the weight during the 



winter, the vessels are distended with blood and the 

 height of functional activity is reached. The an- 

 nexed drawing showing the enlargement of these or- 

 gans in the house sparrow from January to April, 

 serves as an illustration of this process. 



While the enlargement just described is strictly phy- 

 siological, it is frequently exaggerated from various 

 conditions and then becomes a disease. Megnin has 



5. Middle of April. 



