146 



DISEASES OF POULTRY. 



The egg advances into the more glandular and vas- 

 cular part of the oviduct and here two other layers of 

 albumen are secreted and deposited upon it. Each of 

 these is thinner and more watery than the one which 

 preceded. When the narrow part of the oviduct is 

 reached, two denser layers of albumen are excreted 

 forming the mcmbrana putaminis. Enclosed in this 

 manner, having acquired its ovate form and with the 



Fifj. 37.— Section of fowl's egrg'; <7, shell;/-, membra^a putaminis; r, r. 

 layers of soft albumen; d^ chalazce; e^ cicairicula and g-erminal vesicle;/, 

 air chamber. The outline fitrure shows the yolU made up of layers de- 

 posited successively, a, cicatricula, /', grerrainal vesicle. 



small end towards the cloaca, the egg enters the uter- 

 ine or shell -forming dilatation. The inner surface of 

 this portion of the oviduct secretes and deposits 

 upon the membi'ana putaminis a thick white fluid 

 which condenses, becomes calcareous and forms 

 the shell. The time required for the egg to pass from 

 the infundibulum to the uterus, in the common fowl, 

 is said to be from four to six hours, and it may remain 

 here from twelve to twenty hours. 



The color of the egg-shell depends upon pigmental 

 matter secreted by particular follicles of the villous 



