418 ANNUAL RECORD OF SCIENCE AND INDUSTRY. 



the number of men employed at the manufactories, 871 ; the 

 number of sailing-vessels employed, 283 ; steamers, 25. There 

 is a capital of $2,500,000 invested in the business, with 64 

 factories. A market has been found in the West Indies and 

 in England for the guano. 



HYBRID FISH. 



Dr. L. J. Fitzinger has been prosecuting some experiments 

 upon the bastard forms of Salmonidce, now so extensively 

 cultivated in the fish-breeding establishments of Germany, 

 and which, as is well known, attain to maturity and produce 

 completely formed eggs. However, as the result of a careful 

 series of experiments, he ascertained that, under artificial 

 impregnation, these eggs never develop beyond the period 

 of the formation of the eye specks, after which they speedily 

 perish. The hybrids upon which the experiments were pros- 

 ecuted were obtained from the female trout (Trutta lacus- 

 tris) and the male saibling (Salmo salvelinus), and from the 

 female saibling and the male trout {Trutta fario). He thinks 

 that the infertility of the eggs from these hybrids may be 

 considered as an established fact. In the same article ref- 

 erence is made to what is called the Silver trout, or Salmo 

 Schieffer- Mutter i 9 and the opinion expressed that this is a 

 sterile form, but that it is impossible to say from what spe- 

 cies it is derived or whether it is constant. 



EXPERIMENTS WITH YOUNG MAINE SALMON. 



In the winter of 187273 a number of o^s of the Maine 

 salmon were presented by the United States to the State of 

 Wisconsin, and hatched out at Waterville by Mr. IT. F. Dous- 

 man, an experienced fish-culturist of that place. The great- 

 er portion of these were distributed by him in various rivers 

 of the state, a few, however, being left in his ponds. On the 

 2d of December, 1874, in taking out his trout for the purpose 

 of collecting the spawn, he found three salmon in the races, 

 one female and two males. These were all ripe, and lie ob- 

 tained from the female about two hundred eggs, and impreg- 

 nated them with the milt from the males. These eggs he 

 has placed in a separate inclosure, and proposes to ascertain 

 whether they will hatch out, and, if the young can be reared 

 to maturity, what their character will be. The female was 



