246 Diseases of Poultry 



organs of reproduction in the hen. Because of the fact 

 that the corresponding organs in the male are less subject 

 to disease, on the one hand, and are perhaps better under- 

 stood by the poultryman, because of the prevalence of the 

 practice of caponizing, on the other hand, it will not be 

 necessary to discuss the male in detail in this connection. 



The organs concerned in egg production in the hen are 

 shown graphically in Fig. 55. This picture and the accom- 

 panying explanation of it will make clear the various parts 

 of this organ system. All of the points shown in the figure 

 may easily be demonstrated on a hen, killed during a period 

 of laying activity. It should be noted that this picture is 

 somewhat diagrammatic and not in accord with normal 

 conditions in respect to at least two points. These are : (1) 

 there are two eggs in the upper portion of the oviduct. 

 Normally there would be but one there at a time. (2) The 

 proportionate lengths of albumen portion, isthmus and 

 uterus are not correctly indicated. 



In this figure the various numerals have the following sig- 

 nificance : 



1. The ovary; region in which the ovules (later to be- 

 come yolks) are still small in size. 



2. An ovule in an intermediate stage of development, 

 larger than those at 1 , but still not ready to pass into the ovi- 

 duct to be laid. It is contained in a very vascular capsule, 

 known technically as the follicle. 



3. 3. Ovules still larger and containing more yolk. The 

 lower one is nearly ready to leave the ovary and pass down 

 the oviduct. 



4. It will be noted that on all the larger follicles there is 

 one region (forming a line) in which there are no blood vessels. 

 This region (4, 4) is known as the stigma. Here the follicle 

 wall breaks and allows the ovule (yolk) to leave the ovary 

 preparatory to laying. 



