328 



ARTIFICIAL INCUBATION 



within certain limits is permissible, but sudden fluctuations beyond 



this limit will preclude the maintenance of an even temperature 



within the machine. 



The room should be so constructed that it can be thoroughly 



and frequently ventilated, for fresh air is essential to the growing 



embryo, and good ventilation 

 will carry off the fumes from 

 the lamps. 



Arrangements should also 

 be made to materially increase 

 the moisture in the atmosphere 

 when desired, since it has been 

 proved conclusively that moist 

 atmosphere is essential in incu- 

 bation. 



Design. These require- 



FIG. 155. Working plans for incubator cellar. 



ments are best met by a house built partly below the ground 

 (Fig. 155). The machines are then placed low, as this makes them- 

 less susceptible to changes of weather, the room will be cooler in 

 summer and warmer in winter. Two courses are open : Either to 

 put up an incubator room in some permanent building, or to con- 

 struct a low one-story house specially for the purpose. The latter 

 is the usual plan, and, all points considered, is undoubtedly the 

 best. Where a room is fitted up in a building designed for other 

 purposes, there is always danger of fire, and the rate of insurance 

 is higher. Besides, unless the structure is exceedingly well built, 

 the eggs are liable to be injured by shock or jarring from above. 



