(Bulletin of the U. S. Fish Commission, 1887, p. 211.) 
REPORT ON THE PISCICULTURAL 
ESTABLISHMENT OF PIEDRA, 
ARAGON, SPAIN. 
By F. MuntTaADAS. 
All persons who devote themselves to practical pisci- 
culture will remember the change of opinion which took 
place some years ago, owing to the weakness of many 
persons whose experiments proved failures. Our Accli- 
matization Society, however, has never allowed itself to 
be influenced by the ‘‘piscicultural malaria;” it has 
always stood firm and preserved its faith in the future ; 
it well understood that the discovery of two fishermen 
of the Vosges Mountains could not become merely a 
subject of curiosity or pleasure. It is true that a large 
number of amateurs have taken a wrong road, but many 
others have followed the right road, and have made 
marked progress in the successful method of raising 
salmon. 
From the moment that the question of raising large 
quantities of young fry and young trout was agitated, it 
became necessary to pay attention to many different cir- 
cumstances, and not to forget the cost of raising fish; for 
the problem is to derive some profit from the new indus- 
try, and, according to Mr. Larbaletrier’s expression, “to 
make money by pisciculture, and not pisciculture by 
money,” 
All the methods of artificial feeding are expensive, 
and, what is worse, do not entirely answer the purpose; 
it therefore became necessary to find and use natural 
elements. In short, it became necessary to give the 
young trout what it needed. 
I had read in the “ Treatise on Pisciculture,” by our 
late co-laborer, Mr. Carbonnier, that in places where the 
freshwater shrimp (Gammarus pulex) is produced, the 
