PRACTICAL FISTT-CULTURE. 571 



B— ON THE SO-CALLED "DRY" METHOD OF IMPEBGNATING 



SPAWN. 



From Circular No. 3, 1874, published by tbe German Deutsche Fischerei-Vertin, Berlin, 



June 2:2, 18/4. 



[Translation.] 



Following a suggestioa made in Circular No. 1, 187-1, 1 have the honor 

 to lay before the i3ublic the results of a method of dry impregnation 

 practiced by me since 1857, which, if i^roperly carried out, is sure to be 

 successful. 



As I have not read the articles on the subject contained in Circular 

 No. 4, 1871, and in Circular No. 6, 1873, I am not able to say whether 

 the "Eussian dry method" recommended by Livingston Stone is simi- 

 lar to mine; the term "dry method," however, makes a similarity of 

 both methods very probable. 



In the autumn of 1851, 1 established at Wernersdorf, district of Bal- 

 kenhayu, province of Silesia, some trout-ponds, and it was my first care 

 to provide some cheap living food for the young trout x)laced in these 

 ponds in the spring of 1855 and 1858. For this purpose, I had made, 

 close to one of the ponds, a spawning-basin with flat shores and sepa- 

 rated from the pond by a railing. In this basin, I placed some carp, 

 the young of which could through the railing escape into the pond. 



As there were older trout in the other ponds, I likewise endeavored 

 to raise young fish for these, and selected the " nase," w^hich spawns 

 in large numbers in the river Bober in April, and is in those parts com- 

 monly called "zupe," {Chondrostona nasus, Sieb., Gyprinus nasus, Lin. 

 and Bloch.) These fish spawn in large numbers in the shallow stony 

 places in the middle of the bed of the river Bober, places over which 

 the water flowed rapidly and producing considerable waves. 



In April, 1856, 1 placed a large quantity of the roe of this fish — which 

 is easily extracted — in flat vessels filled with Bober water, and after a 

 brief interval I poured in the ripe milt, stirring it with a quill-pen. This 

 method of impregnation differed in no respect from the one I had always 

 successfully employed with trout-spawn. The result of this artificial 

 impregnation, however, was an entire failure. 



The eggs, after having been placed in the water, swelled very rapidly 

 on account of the sticky layer surrounding them, so that no impregna- 

 tion could take place. 



Although I noticed this rapid swelling of the eggs, and their consider- 

 able stickiness, as after a short while they stuck so firmly to the bottom 

 of the vessel that it could be placed upside down without their falling 

 out, I did not find out the cause of this failure till I saw that there was 

 no normal development of the impregnated eggs, but that they were 

 entirely spoiled. 



I determined at my next attempt to pour the milt in immediately, and 



