PROGRESS IN BIOLOGICAL INQUIRIES, 1926 675 
grows rapidly and which will adapt itself to conditions existing in small ponds. 
The bluegill sunfish is the best that we have for this purpose at the present 
time. The yellow perch is very good and has some possibilities. However, 
certain objections have been raised to the use of the yellow perch for this 
purpose. 
Still another problem which, I think, offers possibilities is that of utilizing 
two or more types of food by having more than one species of fish in the 
same pond at the same time. The hatcheries throughout the country usually 
haye only one species of fish to the pond. It is possible that two or more 
species could be utilized in the same pond, and we could get a greater poundage 
from our ponds in that way. This involves the utilization of all food in the 
pond. We are approaching this from two angles—by the introduction of 
forage fishes and by the use of two or more ecologically dissimilar species of 
food fishes. We can introduce one type that feeds on the bottom material 
and another that feeds on the plankton. In the past it has been a matter 
of utilizing one food while others were allowed virtually to go to waste. It 
seems to me that if we once know the practicable combination, we can utilize 
all these various sources of food and thus get a much larger yield. 
Doctor Van Oosten. The black bass taken in commercial seines 
are retained in live boxes until collected by the State. Shortly there- 
after a white film covers the fish. I have seen as many as 25 to 50 
per cent of those fish with white coatings over the eyes. What do 
you think is the cause 
Doctor Dayis. Does it spread to various parts of the head? 
Doctor Van Oosren. No. 
Doctor Davis. It might be a bacterial infection. 
Doctor Van OostEen. These are in Lake Erie. 
Doctor Davis. That is the only thing I can think of at the present 
time. It would be rather remarkable that this is confined only to 
the eyes. It would seem that the fins would become infected 1f it 
is the species I have in mind. There was found, of course, recently 
a number of worms in the eyes. In fact, they have taken several 
hundred out of the eyes of a single fish, but I think this would hardly 
be found in this case. 
TROUT CULTURE AT THE HOLDEN EXPERIMENTAL STATiON 
By M. C. JAMES 
Virtually all of our work bearing on the scientific aspects of fish culture must 
be done at the hatcheries themselves. Formerly we were forced to move to one 
or the other of the bureau’s stations, shipping equipment back and forth and 
making the best of the facilities afforded for undertaking the investigations. 
While every possible cooperation was offered by those in charge of the stations, 
their first object was the production of fish, and our efforts sometimes involved 
the destruction of fish and required space and necessitated changes that might 
reduce production materially. The net result was a failure to achieve the 
fullest results from the scientific work. Consequently the opportunity to 
secure from the division of fish culture a going trout hatchery, to be under our 
control with no obligations for the production of fish for distribution, was 
welcomed. The Holden (Vt.) substation was turned over to us in 1925. It 
probably is the only trout hatchery in the country to be devoted solely to 
scientific investigations of fish-cultural problems. 
Parenthetically I-may say that within the last few days there has appeared 
in the latest issue of the Scientific Monthly an article, by Dr. Nathan Fasten, 
which sets forth, far more concisely than I could hope to, the exact nature of 
these fish-cultural problems. He cites 12 separate phases, and I am tempted 
to refer to a few of the more important ones as an exact definition of the 
purposes of our work in this field. 
Returning to the Holden station, it is sufficient to say that there is a 40- 
trough hatchery building with a room serving as a combination office and 
laboratory, and necessary outbuildings. There is an excellent water supply— 
both spring and brook. Of outside pond and raceway facilities there are none. 
