How to obtain it. 171 



of its existence 80,000 eggs, at a cost of less than three farthings 

 per thousand, and the work, other things being equal, is done 

 satisfactorily. 



Glass gives off nothing, is easily kept clean, and does not 

 require any varnish. Metals, such as are used, are at least 

 partially soluble in water, and in some waters are very soluble 

 indeed, and this renders necessary the use of varnish. A care- 

 fully prepared compound does very well, but some varnishes 

 contain highly injurious ingredients, and here again is a con- 

 siderable source of danger. Notwithstanding all drawbacks, 

 however, I believe very good results have been obtained by using 

 metallic trays. 



I was one day discussing this matter with an American fish- 

 culturist, who assured me that they had discarded grilles long 

 ago, and he exhibited to me, and explained, some of the metallic 

 trays and baskets that were in use in the United States and 

 Canada, and said to be doing very good work there. In reply 

 to the query, as to which system would show the heaviest death- 

 rate, he at once replied that probably it might be a little greater 

 on the metal than on the glass. His reply confirmed my con- 

 victions, and decided me all the more in favour of the glass 

 system. I have since experimented myself, and have also had the 

 benefit of the experience of others, and can only come to one 

 conclusion. It is, that there exists at least one very great 

 advantage in the grille system over every other, viz. that stronger 

 and better developed embryos are produced, and they have a far 

 better chance of growing up and making good fish than any 

 others. 



The counting of the eggs, too, is so easily done on grilles, that 

 in a large hatchery they are found not only a great convenience, 

 but a great saving of labour. They also ensure correctness in 

 estimating the number of ova laid down. The eggs arrange 

 themselves so readily in rows that in a few minutes a large 

 number of them may be accurately counted. For instance, a 

 grille contains a hundred rows of eggs, and there are forty in a 

 row. When multiplied this gives four thousand as the contents 

 of the grille. A box contains ten grilles, which means forty 

 thousand of those particular eggs. In another hatching box are 



