286 



UTILITARIAN ZOOLOGY 



The pond-culture of Carp is carried on in a very systematic 

 manner in some parts of Germany, and it need only be said that 

 the fish are transferred from one pond to another according to age. 



The discovery of the possibility of artificial fecundation, by 

 mixing eggs and milt together, constituted an epoch in fish-cul- 

 ture which opened up far-reaching possibilities the importance of 

 which has only been fully realized of late years. It appears to 

 have been first practised, for salmon and trout, by S. L. Jacobi 

 of Hohenhausen, in Westphalia, so long ago as 1748, and was 

 continued by him and his sons, with profitable results, till 1825. 

 Georo-e III (of England) gave a pension to Jacobi in 1771. 



Fig. 120S. — Staby's Calitornian IVough 



A , Hatching tank, into the outer part of which (^) water flows from a tap [a]; c and d are hatching trays with 

 floors of fine wire-gauze ; c, outflow. B, Tank to catch fry which escape from A when d is removed ; they pass 

 into the space/, but are prevented by the gauze partition g from getting washed away in the outflow to the righL 



Scodand, as usual, was one of the first of other countries to profit 

 by an improvement on old methods, for we find that in 1837 John 

 Shaw, a gamekeeper at Drumlanrig of the Duke of Buccleuch, 

 introduced Jacobi's system. But the beginning of fish-culture on 

 a national scale only dates from 1850, when the French Govern- 

 ment instituted a large fish-hatching establishment at Huningue, 

 in Alsace. At the present time America has profited most by the 

 pursuit of fish-culture, which is largely practised with reference to 

 their rivers and lakes. One type of hatching apparatus suitable 

 for trout and salmon is represented in fig. 1 208 as constructed by 

 Dr. Ludwig Staby, and named by him " the deep Californian 

 trough ". 



The fact that most marine fishes lay floating eggs renders fish- 

 culture in their case comparatively easy, for any quantity of fer- 

 tilized eggs can be collected from the surface of spawning-ponds 



