TRANSACTIONS OF SECTION D. 787 



$ On ike Mechanical and Chemical Changes which take place during 

 the Incubation of Eggs. By R. Irvine, F.C.S, 



Six beu's egf^s were Latched in the usual manner. These e^gs were weighed 

 daily. The loss of weight was progressive during the t (venty-one days of hatching, 

 ranging from 



in No. 1 0'34 gramme 



„ 2 • . 0-36 „ 



,,3 0-25 „ 



on the first day to a maximum of 



in No. 1 050 gramme 



,,2 0-55 



,,3 0-36 



on the twenty-first day, the loss being proportional to their size and weight, the 

 total loss during the tweuty-one days being 



in No. 1 794 grammes 



„ 2 8-46 



„ 3 5-61 



when the chicks chipped tho shells and began life on their own account. 



The other three eggs were not fertile, but during the twenty-one days lost 

 weight also, on the first day losing 



in No. 4 0-23 gramme 



„ 5 . . . . . . . 0-30 



„ 6 0-33 



the loss in No. 4 reaching 0-30 gramme on the 21st day 

 5 „ 0-47 „ „ „ 



11 M " II O'oA ,, ,, „ 



the totals being 



No. 4 534 grammes 



.1 5 7-44 „ 



„ 6 7-38 



The average weight of each of the fertile eggs was 5G-93 grammes, falling to 

 49-55 grammes on the day before the chiclvs liberated themselves from the shells. 

 Thus the average loss sustained by each e°!;g was 7-38 grammes, or 12*96 per cent • 

 so that the average loss per %gg per day was 035 per cent. 



As the results from the unfertile eggs were useless for comparison, a fresh 

 egg was employed to determine the weight of water and solid matter respectively. 



The egg weighed 58-40 grammes 



The shell and membrane (moist, G 92) 5-80 „ dry) 



The weight of yolk, albumen, and water in egg and membrane 



was 52G0 



51-45 grammes of the egg were dried at 101° C, and gave of 



Dry matter ..... 1318 grammes, or per cent. 25-617 

 Moisture 38-27 „ „ „ 74383 



100000 



A newly hatched chick, weighing 40-8 grammes, was dried in the same 

 manner, and after the moisture had been driven oft' there was left 



Dry matter 10-9 grammes, or per cent. 26*715 



Moisture ...... 29-9 „ „ „ 73-285 



100-000 

 3 £2 



