MANAGEMENT OF INCUBATORS. 77 



the time, so that the drawer varies very little when the 

 quantities are chosen with judgment, while any little excess 

 or defect on a single occasion has comparatively mild effects. 

 If the machine is filled with eggs at once, the ventilators should 

 be kept nearly closed for the first nine days, half opened on the 

 tenth day, rather more the next day, and thenceforth the 

 drawer freely ventilated. If two incubators or a divided 

 drawer are used, the eggs are kept in the close situation at 

 first, and then moved to the ventilated one. Particular 

 attention must be paid to the supply of moisture beneath, and 

 to the removal of any bad egg, and each time the machine is 

 visited the eggs must be withdrawn, turned, and exposed to 

 the cool air for from fifteen to twenty minutes. The eggs 

 should be turned in opposite directions on succeeding days. 



As hatching proceeds, it will be found that less and less 

 hot water is required, owing to the " vital " heat developing 

 in the eggs themselves. This must be carefully attended 

 to. On the other hand, fresh cold eggs would lower the 

 temperature; and therefore fresh eggs added after a star.t 

 should be first warmed for a minute or two in water heated to 

 about 105. In a very dry room a loose pan of damp earth 

 under the incubator is an advantage, or shallow tins may be 

 placed in the egg-drawer itself to supply more moisture. The 

 heat should be kept from 103 to 106 as nearly as possible. 

 The temperature of the drawer should be noted at a glance 

 when the drawer is opened, as it will rapidly fall when exposed 

 to the air. Eggs should always be tested for fertility at an 

 early date, as bad eggs in a drawer are a great drawback to the 

 whole batch ; and any fetid smell should at once lead to a 

 rigorous examination, and the sprinkling on the earth-trays of 

 a few drops of Condy's fluid. Every two or three days, when 

 turning the eggs, the outside ones should be moved to the 

 middle, or the front ones to the back, and vice versd. When 

 hatching time arrives, the chicks should be removed about 



