454 LIQUID PARTS OF ANIMALS. 



The yolk has parted with some of its phosphorus, which appears 

 in other principles of the egg. 



The following table shows the contents of the egg at the end 

 of the third week, or at the full term of incuhation in two differ- 

 ent eggs: 



No 1. 

 Grains. 



Residuum of albumen, membranes, &c. 29-5 



Animal, . 15 . 555-1 . 



Yolk, Ifrfi .'si^j 167-7 xj.& 



Shell and loss, 247 -7 



1000-0 1000-0 



At this period all the important changes of incubation are com- 

 pleted. The albumen has disappeared or is reduced to a few 

 dry membranes together with earthy matter. The yolk is con- 

 siderably reduced in size, and is taken into the abdomen of the 

 chick, while the animal has attained a weight nearly equal to the 

 original weight of the albumen, together with that lost by the 

 yolk, minus the total loss of weight sustained by the egg during 

 incubation. The alkaline matters and chlorine have diminished 

 in quantity, while the earthy matters have considerably increased. 

 The following table shows the fixed constituents in the contents 

 of two eggs at the end of the period of incubation : 



Sulphuric Phos. Chlorine. Potash, Lime, &c. 



acid. acid. &c. 



Grains. Grains. Grains. Grains. Grains. 



Residue of albumen, &c. 004 0-12 0-09 0-23 J2 



Animal, . 0-44 3-02 0-55 2-26 2-58 



Yolk, .><?. 0-04 1-06 0-03 0-06 1'26 



0-52 4-20 0-67 2-55 3-96 



Residue of albumen, &c. 0-03 0-13 0-09 0-25 0-12 



Animal, . 0-21 2-71 0-68 2-12 2-60 



Yolk, V J V o-02 1-23 0-06 0-03 MO 



0-26 4-07 0-83 2-40 3-82 



It follows, from these experiments, that during the last week 

 of incubation the yolk loses most of its phosphorus, which is 

 found in the animal converted into phosphoric acid, and com- 

 bined with lime, constituting its bony skeleton. This lime does 

 not exist in the recent egg, but is derived from some unknown 

 source during the process of incubation. 



