REQUISITES OF A GOOD INCUBATOR. 277 



so perfectly as the hen, its exemplar, yet it can when 

 properly directed approach so near her work as to keep 

 within the bounds of the fluctuations a well-vitalized egg 

 or a well-hatched chick can undergo without serious 

 injury. The fact that departures from the perfection of 

 nature so wide as to be barely compatible with success, if 

 not wholly fatal to it, are liable to occur, renders it 

 advisable that the natural method should be adopted in 

 general, and the artificial resorted to only under special 

 circumstances, as, for example, at such times and places 

 as do not afford sitting hens. The writer would not 

 publish, regarding a good incubator, a parallel to the 

 famous " volume" on the snakes in Ireland containing 

 only six words : "There are no snakes in Ireland," or 

 repeat to a party about to buy an incubator the advice 

 of the redoubtable Mr. Punch to folks contemplating 

 matrimony: "Don't ;" for both incubators and brood- 

 ers have their uses and on occasions are indispensable. 



TEMPERATURE. 



The correct degree of heat for the egg chamber of the 

 incubator is found by taking the outside temperature of 

 the sitting hen at the point of her contact with her eggs, 

 near which, during what has betn termed the sitting fever, 

 a network of blood vessels becomes specially distended, 

 capable of furnishing plentiful heat to be received by 

 the eggs and nest. The internal temperature of the hen 

 some distance from her skin is given by Charles A. 

 Cyphers, whose close study and clear description of the 

 process of incubation merit unstinted praise, as 109 to 

 110 at the beginning of her sitting term, decreasing 

 slightly towards its close, to offset partially the develop- 

 ment of heat within the eggs themselves consequent on 

 the growth, blood circulation and breathing of the 

 chicks. 



