158 How to obtain it. 
with grilles. Never half fill one, and lay down ova before putting 
in all the grilles. There would be a danger of disturbing the eggs 
in the lower half of the box, whilst placing grilles, etc., in the 
upper. Many persons would probably say that they could do it 
quite easily without doing the slightest harm, and I have no doubt 
they could—but there is no object to be gained, and harm may 
be done. It is one of those points the observance of which tends 
towards success, and I would not give much for the results from a 
hatchery where such rules were not strictly observed. 
Tn laying down the eggs always commence at the lowest end 
of a set of boxes, and go on filling as the ova comes into the 
hatchery, until that set or series of boxes has received its full 
complement of ova. In a large hatchery it is sometimes desirable 
to have several sets of boxes filling at the same time. This does 
not matter. The object is that as the eggs are laid down, so shall 
they hatch in rotation, and it would be bad policy to arrange to 
have some hatching in one of the upper boxes, whilst others were 
being incubated in a box below. 
There will probably be a few white eggs, and these should 
be picked out. This may be done either before they are laid 
down or after, or if the former course be taken both before and 
after, for some will probably turn white either whilst being laid 
down, or very soon after. They are easily picked over whilst in a 
bowl or other vessel, as owing to a slight difference in the specific 
gravity, the white eggs rise to the top when slightly agitated, 
either by pouring in water or by means of the hand. The reason 
why some of them turn white is that they have absorbed water, 
which acts on the albumen of the egg, causing a white precipitate 
to form, and this goes on more or less during the whole time of 
incubation. Where a good impregnation has been secured there 
will not be many white eggs. It is the badly impregnated and 
unimpregnated ova that turn white as soon as the. water percolates 
the shell of the ovum. Some unimpregnated or “blind eggs” 
remain unchanged until all the others are hatched. These will 
do no harm, and may either be picked off any time at leisure, or 
left until all the hatching is completed, when they can be 
removed with the grilles. 
A variety of implements have been used for the purpose of 
