82 Veterinary Elements. 



the grit before mentioned, heredity has a powerful 

 influence similar to its results in cattle. The time 

 necessary for the bringing forth of the offspring varies 

 according to the species, chickens are hatched out 

 in three weeks, goslings, ducklings, and poults (the 

 young of the turkey) in a month. The development of 

 the chick in the egg, by the aid of the incubator, sup- 

 plies the investigator with a large part of his knowledge 

 regarding the development of the young animal in the 

 womb, beginning with the time when the ovum was 

 impregnated in the tube until it is expelled from the 

 womb. The egg is kept at an average temperature of 

 103 degrees when in the incubator. Formation of an Egg. 

 Fowls have only one ovary and one oviduct at maturity; 

 from the ovary comes the ovum, consisting of the yelk 

 enclosed in a thin membrane, at the upper part of the 

 oviduct it is fertilized, it is then forced down the oviduct 

 by contractions of that tube; during its downward course 

 being coated with a dense layer of albumen, lower down 

 the oviduct more albumen is added, the last albumen 

 added being more watery than the first, then a thin film- 

 like membrane formed of albumen is added; still further 

 down, the small end outwards, it reaches the uterine 

 widening where it is coated with a thick white fluid 

 which hardens and becomes the shell. The .color of the 

 egg shell is got from the color secreting villi of the 

 uterine cavity, the pores, in the egg shell being the 

 result of contact with those villi. The shell substance 

 contains carbonate of lime with a little carbonate of 

 magnesia, phosphate of lime and magnesia; food con- 

 taining these materials or the materials themselves must 



