SOME OBSERVATIONS IN FROG CULTURE 



By W. H. Safford 



The work of the Department of Fisheries of Pennsyl- 

 vania in frog culture begun in the year 1903 has steadily 

 progressed; and the action of the Legislature of that year, 

 which passed a law giving protection to frogs has greatly 

 increased their importance. As with any other kind of 

 pond culture, however, we find a great many difficulties to 

 retard our work. We also find a great difference in the 

 modes of cultivation applicable to the several species 

 of frogs. 



In the beginning of the work we were unable to dis- 

 tinguish the eggs of one species of frog from another. The 

 leopard and the green frog, being two of the earliest to 

 spawn, were the ones first experimented with. My first 

 year's work was with these eggs, under the belief at that 

 time that they were the eggs of the common bullfrog. 

 But, as the season advanced, I found, to my disappoint- 

 ment, that they were nothing of the kind. Out of an 

 estimated 500,000 eggs that I had in a pond I think I did 

 not succeed in developing more than fifty frogs. 



In the meantime experience had taught us to distinguish 

 the eggs of the common bullfrog. We found that with 

 the exception of coloration the eggs of this species (which, 

 by the way, is very large, sometimes reaching a weight of 

 one or two pounds) were different in every respect from 

 any other. For instance, the leopard, or small green frog, 

 casts its eggs in a round, solid, gelatinous mass, which will 

 be found in what you might call spawning grounds, where 

 from 10 to 50 bunches can be gathered at one place. The 

 water inhabited by these frogs is usually the pools in low, 

 swampy lands. The common bullfrog, on the other hand, 

 casts its eggs in a thin gelatine fluid that sometimes will 



