212 BULLETIN OF THE UNITED STATES FISH COMMISSION. 
I had read in the Treatise on Pisciculture, by our late colaborer, Mr. i 
Carbonnier, that in places where the fresh-water shrimp ( Gammarus 
pulex ) is produced the raising of salmonoids was easy. I ransacked my 
waters for these precious crustaceans, and, having found them in con- 
siderable quantities in the sources and along the course of the Devil 
Kock Brook ( Pena del Diablo), I went to work and had my first rearing 
basin constructed. It was a complete success, and I had the honor to 
report it to the Acclimatization Society, which rewarded me by one of its 
medals. My young fish swallowed the little shrimps with the greatest 
delight, and seemed to care very little for the coagulated blood which 
was given to them in accordance with the instructions of the majority 
of treatises on pisciculture. 
Ever since my first season I have used nothing but small shrimps 
lor feeding my young trout, which grew amazingly fast. This method 
was followed during the first eight months. Later they found in the 
large basins (besides myriads of small shrimps) tadpoles, gudgeons, and 
craw fish, of which they are very fond, especially during the shedding 
period of these crustaceans. In a special compartment I tried chopped 
meat (mutton, rabbit, etc.) ; but when I found that the carnivorous trout 
did not develop any quicker than the ichthyophagous ones I fed all of 
them on fish and crustaceans. 
The enemies of the young fish (water-snakes, water-ousels, water-rats, 
etc.) committed great ravages in my open-air basins; and, with a view 
to prevent these ravages, I hlad a basin constructed of cut stones, 10 
meters (32.8 feet) long, 1 meter (3.28 feet) broad, and 50 centimeters 
(1.64 feet) deep. The whole was covered by a small house with windows 
protected by gratings and a very close net-work of wire both down and 
up the stream. 
The experiment had a twofold interest, viz: On the one hand to keep 
away the enemies of the young fish, and on the other to prove the suc- 
cess of my method of feeding the young fish after the umbilical sac had 
been absorbed. This twofold object was attained, and I am enabled to 
state that not only was the loss smaller, but the young fish kept in this 
basin developed more rapidly than the others. When, in September, I 
transferred the young trout to more extensive waters, those which had 
come from the stone basin gained on the others in every respect. 
In places where there is clear and cool water containing some lime, 
and where the fresh- water shrimp reproduces naturally, I have dis- 
covered the best method of raising salmonoids. It therefore gave me 
great pleasure to read that at the Gremaz establishment Messrs. Lugriu 
and du Boveray had succeeded in solving the problem of raising young 
fish by the same means which I had employed here, and which I had 
described in the report which I had the honor to submit to the Accli- 
matization Society in July, 1872. 
The closer we follow nature, the more certain we are of success. It 
may give an artificial pleasure to see a few young fish in a hatching- 
