Scientific Intelligence — Zoology. 383 



which vary with the species on which we operate. The ova of fishes 

 of stagnant waters and fish-ponds require little care ; it is sufficient 

 to phice them in a spot having a bottom of aquatic plants, where the 

 water is tranquil, and of little depth. They ought, besides, to be 

 protected, in some way, by a kind of net- work, for example, against 

 the attacks of their enemies. The ova of fishes, inhabiting running 

 waters, are a little more difficult to hatch. The following is a very 

 simple process, which has been practised with success sinco the middle 

 of the last century by a German, Count Golstein, to bring out the 

 young of salmon : — Construct a box with a moveable cover, about 

 4 metres long, by 30 or 35 centinietres broad, make an opening of 

 16 or 17 square centimetres at the two extremities, and close them 

 by a close grating. The bottom of this box is covered with sand and 

 very clean gravel, then the apparatus is placed on the margin of a 

 running stream, in such a manner that a slender stream, about an 

 inch deep, may flow gently through it. We thus obtain a kind of 

 artificial rivulet, protected from all invasion from without. The fe- 

 cundated ova of the salmon are then placed upon the gravel, the case 

 is closed, and from time to time care is taken to clean the ova by 

 agitating the water slightly with a feather to remove the least depo- 

 sit of mud, which, by adhering to their surface, might interfere with 

 the success of the operation. In about thirty or forty days, accord- 

 ing to the temperature, the young v'«almon issue from the egg; they 

 live for some time in the box, and then leave it for the adjoining ri- 

 vulet, which ought to lead to a fish-preserve or pond. If the latter 

 is conveniently arranged, the young salmon remain there and ac- 

 quire their ulterior development. Count de Golstein assures us that 

 he obtained, by a single experiment, 430 salmon, and that they en- 

 abled him to stock several fish-ponds. It will easily be seen that 

 this same process may be applied to the rearing of all kinds of fresh- 

 water fishes. 



If I am not deceived, we have here the necessary hints to give 

 birth to a kind of economy altogether new, at least, in France. 

 Young salmon live very well in fresh water till the age of two or 

 three years ; at this period, they have reached a length of from 35 

 to 40 centimetres, and are much esteemed on account of the delicacy 

 of their flesh. These facts, well known in Scotland, have led many 

 to attempt to discover the means of inducing salmon to spawn in 

 fish-ponds where the young may be reared for sale. This end has 

 been attained by forming canals of running water which terminate 

 in the great rivers ascended by salmon. By means of work.s, often 

 very expensive, cascades, too high to be surmounted, havo been 

 broken down into falls which these fishes can easily ascend. By 

 combining these various means, salmon have been conducted into 

 countries to which they never before penetrated, and even into basins 

 prepared to facilitate the development of the young. Artificial fe- 

 cundations, and transporting young salmon hatched near fisheries, 

 would render all these preliminary expenses unnecessary, and allow 



