156 POULTRY DISEASES 



shell are formed about a small portion of detached yolk, a minute 

 piece of hardened albumen or a bit of coagulated blood instead of 

 the normal yolk. 



Double and Triple Yolk Eggs.— These eggs with two yolks are 

 common. They are caused by two yolks getting into the oviduct and 

 being enclosed together in the albumen and shell. Three-yolked eggs, 

 which are rare, have a similar origin. 



Bloodspecks, Blood Rings. Egg Inclusions. — These have little sig- 

 nificance; particles of coagulated blood, due to hemorrhage when the 

 ovum (yolk) is discharged from the ovary, are most common, but 

 lumps of bacteria, worms, fecal matter, etc., have been found. 



Blood clots may be found in either the yolk or white (albumen). 



If hemorrhage occurs in the yolk, the clot has formed in the 

 ovary before it was delivered into the oviduct. If the clot is in 

 the white it has occurred in the upper portion of the oviduct. 



Dwarf Eggs 



Dwarf eggs of fowls vary greatly in size and shape. There are 

 two distinct types; first, the prolate spheroidal shape, similar to 

 a normal egg; and second, the cylindrical type. 



The internal structure of the dwarf egg varies in its makeup. 

 Some dwarf eggs contain a small yolk surrounded by a membrane, 

 others a small quantity of yolk without a yolk membrane, and 

 still others no yolk. When yolks are present usually there is no 

 germinal disc. 



The albumen in the dwarf eggs differs in its density. It may be 

 dense and appearing like that of a normal egg. There is also found 

 all gradations between these two extremes. The tendency is to a 

 density greater than normal. 



The size of the egg is apparently related to the size of the 

 nucleus which by its presence gives stimulus to albumen secretion. 



A bird may suffer a disturbance in her physiological functions 

 of reproduction, and produce dwarf eggs since normal eggs are 

 produced both before and after dwarf egg formation and the cause 

 of such dwarf egg production is of a temporary character. Dwarf 

 egg production appears in both pullets and old hens and occurrs 

 at a rate of five to eight per 10.000 eggs produced. It may occur 

 at any time during the laying period, but most often in the spring 

 or early summer. 



The yolk of an egg constitutes, on an average, 24.37 per cent of 

 the weight of the egg, and 33.91 per cent of double-yolked eggs and 

 35.52 per cent of triple-yolked eggs. 



The shape of the eggs is determined by the action of the circular 

 and longitudinal muscular fibers of the oviduct wall. 



The egg being a semifiuid body has a tendency when free, to 

 assume a globular shape, but at the time of the formation of the 

 membrane it is larger than the oviduct lumen, hence there is a 

 tendency under pressure exerted by the oviduct wall to elongate 

 the mass in the direction of the long axis of the oviduct as this 

 is the line of least resistance. 



The degree of pressure will depend upon the size of the egg and 

 the tonicity of the muscular coats of the oviduct. 



The exact length as compared to the breadth will depend upon 

 the tonus of the circular and longitudinal muscular fibers. A strong 

 tonus of the circular fibers and weak longitudinal fibers may 

 greatly alter the normal shape of the egg. The two sets of muscles 

 are independent in their action. 



