164 How to obtain it. 
fish will answer admirably (see Fig. 13, page 155) for this purpose, 
and with a good current of water flowing through it, twenty grilles or 
more may be reversed in succession and all the eggs washed at once. 
Much care is required in carrying out a piece of work of this kind. 
It should not be done thoughtlessly. Eyed ova are very easily 
suffocated, and this fact should be borne in mind at all times 
when it becomes necessary to deal with them in large masses, or 
when they happen to be placed temporarily in bowls or other 
vessels containing still water, as may be the case when packing 
for a journey. 
Should any eggs adhere to the grilles, wash them off gently. 
The dirt will by this time have mostly separated from the eggs, 
which may be washed in the usual way as recommended at 
spawning time, great care being exercised in the operation. When 
as clean as they can be made, replace them on clean grilles in the 
newly-cleaned hatching-box, and repeat the process with another 
lot, and so on through the hatchery. With regard to the washing 
of younger eggs, I would advise the reader, if disposed to try it, 
to experiment on a few first, and note the result. More practical 
information will be procured that way than from any books. The 
best way, however, is to guard against sediment, and there are few 
places where it cannot be kept out of a hatchery, The filter 
screens should be cleaned twice daily, or oftener, if required. To 
do this, take them out one at a time, and wash them under a tap. 
A brush will be found useful for this purpose. 
During each day of the period of incubation there will be a 
few white eggs to pick out which should be duly attended to. 
After a washing process there will probably be a great many, or 
what will appear to be a great many in comparison with other 
days. There is not necessarily any cause for alarm at this, as 
the agitation will cause the water to percolate the shells of a 
large proportion of the blind or unimpregnated eggs, which will 
thereupon turn opaquely white. There will be less picking to 
do afterwards—at least there ought to be—and should this not 
prove to be the case, then harm has been done to the eggs during 
the washing operation. 
The first appearance of the eye spots is always an interesting 
sight, and especially to those who have only just commenced 
