THE ABTiriCIAL INCUBATION OF OVA. 63 



will be advisable to do so. But, I repeat, no force 

 must be employed ; if the ova is ripe, it is detached 

 from the membrane to which, during the period of 

 gestation, it has hitherto been attached, and it wiU 

 pass out easily. If, however, it be not quite detached, 

 but the process has only barely commenced, by too 

 much force you will tear the eggs from the mem- 

 brane, which are then totally useless, as they are 

 immature, and will not hatch, and you will cause a 

 slight discharge of blood with the ova. When this is 

 the case, you may conclude that you have ruptured 

 the membrane, and the chances are two to one that 

 the fish dies, and, as I have said, the eggs are useless, 

 or worse, because they do not, for the most part, show 

 that they are barren for weeks after — perhaps months 

 ■ — during which time the pisciculturist is in a fool's 

 paradise, thinking what a fine stock of ova he has in 

 his trays; and he sacrifices time and space, which 

 are invaluable to him, to infertile ova. Inexpert 

 attendants are very liable, for the sake of bring- 

 ing home an apparently good stock of ova, to do 

 this ; in fact, it may be termed the vice of inex- 

 perience. If the ova be ripe, it flows in one unbroken 

 stream from the fish, while under pressure, until the 

 whole is exhausted. When as much ova is in the 

 dish as can conveniently be milted, lay the female 



