ARTIFICIAL BREEDING AND CONVEYANCE OE EGGS. 31 



The fish while being spawned* is held with its body somewat sideways, its 

 tail obliquely downwards, and its abdomen turned slightly towards the manipu- 

 lator ; if large its body may also be a little bent. A pan to receive the eggs is 

 placed on the ground as near as convenient to the fish's vent, then gentle pressure 

 is exercised commencing from the ventral fins and continued downwards towards 

 the vent. The ova which are thus pressed out may be treated either by the moist 

 or the dry process. In the moist some water is first put into the pan which is to 

 receive the eggs, for it used to be held that if ripe milt and ova were mixed 

 together in water the fish-culturist would be most closely following the operations 

 of nature. In the dry process (inaugurated by M. Vrasski in 1856) the use of 

 water at this time is dispensed with, the eggs being expressed from the fish 

 directly into a dry pan (into which of course a little water will fall from the 

 surface of the fish) , over these eggs, milt from a male is distributed ; the pan is 

 now tilted backwards and forwards, causing the contents to be well mixed. After 

 allowiDg time for this comingling to take place, water is added to the depth of 

 two or three inches ; this is gently stirred with the hand and then allowed to 

 stand until the eggs harden or " frees " as it has been termed, being a period 

 from one- to three-quarters of an hour according to the temperature, taking 

 longest in cold weather. In the moist process the average success in fertilizing 

 eggs was about 50 or 60 per cent., by the dry process as many as 95 per cent, are 

 not uncommon, and even all have been fertile. 



The ova as extruded are soft and adhere to whatever they come in contact 

 with, apparently owing to the absorption which is going on through their shells, 

 for water is gradually imbibed as seen most distinctly in eggs of such species as 

 the guiniad or Goregonus, and first observed by Ranking in the egg of the common 

 stickleback. When the interspace between the outer and inner coat is filled 

 absorption necessarily ceases, and when this occurs the ovum no longer adheres 

 to contiguous objects but "frees " itself and is seen as a hard, almost round, and 

 elastic body. Now more clean water has to be carefully poured over the eggs and 

 continued until no efiete milt remains, and so soon as the water is no longer 

 discoloured they may be transferred to the carrying can in the proportion of 

 about one-third eggs and two-thirds water. They are then removed to the 

 incubating house and gently distributed by the aid of a feather over the bottom 

 of the hatching tray. 



There are some points respecting the conveyance of the eggs of these fishes 

 which may well be discussed in this place : when recently taken they wUl bear 



* Different modes of spawning fish have been adopted in this country. Shaw, in 1836, 

 obtained salmon ova from a redd which he placed in gravel and hatched in a stream of pure 

 spring water. He in 1837 took two spawning fish and having dug a trench in the gravel, he 

 directed a stream through it two inches deep ; the fish were then held side by side and the eggs 

 and milt pressed out into the stream, and after a few minutes they were removed to another 

 stream where they were hatched. Boccius, in 1848, in his Treatise ore tlw Management of Fish, 

 observed that " the principle of artificial spawning I have been acquainted with as far back as 

 1815 .... Should the fish be all right, take a large earthenware pan, with about two quarts of 

 spring water at the bottom, and, holding the female fish up by the gill-covers, draw your hand 

 downwards from the pectoral fins to the anal point." The milt was to be similarly obtained from 

 the male, the whole agitated with the hand for about a minute and the eggs were now to be 

 spread on the shingle in the hatching apparatus, being careful one was not above another, then 

 two inches of shingle was to be placed above the ova and spring water permitted to' flow freely over 

 them. Messrs. Edward and Thomas Ashworth's experiments were made in a similar manner to 

 Shaw's, they commenced December 20th, 1852, at Outerard, in Galway, as related by themselves, 

 and their manager, Mr. Eamsbottom, added the advice to keep the eggs submerged, which must 

 always be attended to even when the ova or milt is flowing from the fish. Buckland (1863, Fish 

 Hatching) advised the same process as had been advocated by those who had preceded him, and 

 it was not until an article by Livingston- Stone in The New York Citizen and Mound Table of March 

 9th, 1872, first drew attention to the dry process of M. Vrasski that any considerable change was 

 made and this plan generally adopted. Prior to this time the use of gravel in hatching trays had 

 been abandoned by most fish-oulturists as being a great source of mortality among the eggs due 

 to the elements of mischief it introduced in spite of the greatest care. It was also ascertained 

 that placing covers on the hatching trays and thus excluding the light, or else hatching the eggs 

 in darkened rooms, were sufficient for the necessary exclusion of light during the period of 

 incubation 



