OBSEEVATIONS ON INCUBATION. 345 



the egg under the action of the air-pump. They were mostly in the big end, but 

 they were not confined to that end. 



The remaining three eggs were put under a hen with ten recently laid. The 

 latter were hatched on the 11th of August. Of the eggs subjected to the air- 

 pump, No. 4 only was hatched, and only about four or six hours later than the 

 ten. The chick was healthy. The two aborted eggs were found to have lost as 



follows: — 



No. 2, ... 53-9 grs. | No. 3, ... 3216 grs. 



Both sank in water. Of No. 2 the yolk and white were in part mixed ; a por- 

 tion of the white was free and thickened. The contents had no unpleasant smell ; 

 no embryo could be found. Of No. 3 the yolk and white were found distinct, each 

 in its proper membrane. In neither of them was there any apparent change, 

 except that the white seemed more liquid than usual. Neither had any offensive 

 smell, merely that of a stale egg. 



IV. Of Eggs kept in Lime Water. 



1. On the 17th of July three newly laid eggs were put into lime water, in 

 which there was a great excess of lime. They weighed as follows : — 



No. 1 weighed 1024-5 grs. No. 3 weighed 937T grs. 



2 ... 900-5 „ I 



The vessel used, which was of glass, held little more than a pint ; it was full 

 nearly to the mouth, and the mouth was only just large enough to admit the 

 eggs. It was closed by a cork, and placed in a dark cupboard, where the tem- 

 perature was about G3°, and subject to little variation. Taken out on the 17th 

 of September (the water was covered with a crust of carbonate of lime), they 

 were found to have gained as follows : — 



&* 



No. 1, ... 2-3 grs. No. 3, ... 40 grs. 



2, ... -6 „ J 



On the same day they were put under a hen with seven fresh eggs. Of the 

 latter all but one were hatched on the 11th of October. This one, on receiving a 

 blow, broke explosively, scattering wide its yellow, offensive contents; the 

 explosion was nearly as loud as that of a pistol, showing how much the air it 

 contained was compressed. Each of the eggs from lime water was unproductive. 

 They were found to have lost as follows : — 



No. 1, ... 25-7 grs. I No. 3, ... 109 grs. 



2, ... Ill „ I 



All three sank in water. No. 1, broken under water, gave off two or three 

 bubbles of air ; the quantity was too small for analysis. The yolk and white 

 were distinct, but the former seemed unduly thin, as if from the admixture of 



VOL. XXIV. PART II. 5 A 



