THE HISTORY OF FISH-CULTURE. 505 



was necessary, according to the manual which Mr. Vrasski followed, to 

 press the spawn from the females into a vessel filled with water, to 

 place the milt of the males in another vessel, and, after having diluted 

 the fecundating-liquid, pour it into the vessel containing the eggs. Mr. 

 Vrassky had meanwhile observed that fecundation was less successful 

 if there was any long interval between the time of extracting the spawn 

 from the female and the time of its coming in contact with the milt. If 

 this interval exceeded ten minutes, fecnndatiou failed almost entirely. 

 By numerous microscopic observations made with Dr. Knoch, a learned 

 embryologist, Mr. Vrasski convinced himself that, in coming in contact 

 with water, the spawn absorbs this liquid, and that the process of 

 absorption takes no longer than half an hour 5 but that spawn placed 

 in a vessel in a dry state remains a long time without changing, 

 and without losing its property of absorbing water and of receiving 

 spermatozoids. The spermatozoids of the milt, when brought in con- 

 tact with water, make violent and rapid movements, which, however, 

 last only one and a half or two minutes, while milt kept dry in a vessel 

 or on a glass plate preserve > its qualities for several hours, during which 

 time the spermatozoids show under the microscope the same rapid 

 movements which they make in water the moment they leave the body 

 of the fish. In making experiments with the river-perch and the 

 Acerina vulgarised., on milt that had not yet reached its mature state, he 

 found that some drops of milt kept in a perfectly dry and well- closed 

 cylinder had not lost their original qualities, even after six days in the 

 ordinary temperature of a room. By combining these data with the 

 circumstance that spawn and milt when taken from the bodies of fish 

 do not come out all at once, but run out gradually and slowly, Mr. 

 *Yrassky arrived at the conclusion that, by putting the spawn and the 

 milt immediately in water, the larger portion of the eggs have time 

 enough to get completely soaked, and that, the majority of the sperma- 

 tozoids lose their movements before the pisciculturist has time tO' mix 

 the prolific water with the spawn. Then Mr. Vrasski commenced to 

 put spawn and milt in vessels without water, and to pour the fecundating- 

 liquid over the eggs immediately after having diluted the milt. The 

 results were entirely satisfactory, for not a single egg remained barren. 



After having achieved such a brilliant success in fecundating spawn, 

 Mr. Vrasski associated himself with two others, with the view 

 of founding an establishment on a large scale. For this purpose he 

 used the Pestooka, a river which joins Lake Pestow (IJ miles long) and 

 Lake Velio, (about 4| miles long;) with the water of this river he fed 

 several basins and fish-ponds, where the water could be made to rise or 

 fall by means of water-gates placed farther up the river at the place 

 where it leaves Lake Pestow. 



The building, built of wood, on stone foundations, is 12 sagenes (84 

 feet) long, and 6 sagenes (42 feet) broad. 



The water oi a pond is cohducted into the establishment by means of 



