254 SCIENCE PROGRESS. 



required in the case of the herring with its adhesive eggs. 

 The great principle is to keep the eggs in gentle motion 

 amongst pure sea-water of the proper temperature. As 

 first prominently brought forward by Lord Playfair, of 

 St. Andrews, the Americans have chiefly experimented 

 with the cod, and even so early as 1884 the fishermen on 

 the neighbouring shores of the United States recognised 

 the Commissioner's labours in shoals of young fishes which 

 they termed "Commission cod". To a small extent, how- 

 ever, they have also dealt with the eggs of pollack, 

 haddock, sea-bass (Serranus), Spanish mackerel, common 

 mackerel, scup (Steiiostomus), squeteague (Cynoscioii), tautog 

 (Taut ago), cunner (Ctenolabrus), with the sand-dab and the 

 spotted flounder, both of which, like all the preceding, have 

 buoyant or pelagic eggs, and with a flounder (Pseudo- 

 pleuronectes Americanus), which has demersal (i.e., non- 

 floating) adhesive eggs. The anadromous shad has also 

 been hatched in enormous numbers, and with very great 

 success, but this form does not so much concern us at 

 present. Altogether (up to 1891), larval cod to the 

 number of eighty millions have been placed in the sea by 

 the Commission ; and Colonel Marshall Macclonald, the dis- 

 tinguished head of the department, is of opinion that as 

 the result of these operations cod have appeared in places 

 where they were formerly unknown. He specially points 

 out that a variety with dark spots on the back, and hatched 

 at Gloucester marine station, had been got for the first time 

 in the waters near Plymouth Harbour in schools of fishes 

 of about four pounds weight. 



In the same continent, another station for the hatching 

 of the ova of the cod has been for more than three years 

 in operation at Dildo Island, Newfoundland, under the 

 government of Canada. Up to 1893 ( anc ^ f° r t ^ e three 

 years) two hundred and twenty-two millions of larval cod 

 had been placed in the water in an increasing ratio year by 

 year. Thus in 1893, two hundred and sixty-five millions 

 of the ova of the cod were placed in the hatching-vessels, 

 and one hundred and sixty-five millions of larval fishes de- 

 posited in the sea, or about 62^ per cent. At this station 



