PROGRESS IN BIOLOGICAL INQUIRIES, 1938 ok 
to anglers. At these stations a complete census was started on May 
21, the opening day of the fishing season, and will continue until 
the close of the season on March 21, 1939. Bottom samples, two 
types of plankton samples, and chemical data are also being col- 
lected on these lakes. 
In addition to the lakes under management, seven ponds have 
been set aside for experimental work. This number will be in- 
creased as needed. These ponds will be utilized for stocking experi- 
ments and study of methods to increase the food supply of game fish 
in these waters, as the basis for improvement in the management 
program. 
In the Choctawhatchee National Forest there are a number of 
streams that are inhabited by largemouth bass at the lower end 
where they enter coastal bays, but which contain no game fish 
higher up. These streams are peculiar in that the temperature of 
the water is about the same throughout the year. A study is being 
made of the physical conditions and life in these streams to deter- 
mine how they can best be utilized. 
Experiments relating to hatchery problems will be started early 
in 1939 when the remodeled ponds at the Welaka station will be 
ready for use. 
PARASITES AND DISEASES OF FISH 
Facilities at Seattle, Wash., for the study of problems relating to 
fish diseases were greatly increased during the past year. These 
studies are under the direction of Dr. F. F. Fish. ‘Two experimental 
laboratories are now available, each operated for a slightly different 
purpose. One is an enlargement of the field laboratory constructed 
at the Quileene (Wash.) hatchery in 1987. The original temporary 
structure has been replaced by a permanent building constructed by 
the Division of Fish Culture according to plans provided by Dr. 
Fish. As this laboratory was planned primarily for testing scien- 
tific discoveries under controlled field conditions, it is not suited to 
all types of experimental work. 
A second experimental hatchery has been provided, through the 
generous cooperation of the University of Washington, in the base- 
ment of one of the university buildings. This laboratory is sup- 
plied with chlorinated water, which is subsequently dechlorinated by 
passage through an activated carbon filter, thus assuring a disease- 
free source of water. The laboratory contains 24 small troughs 
which have proved highly satisfactory for this type of research. 
The main water supply to the troughs is controlled by a manually op- 
erated master valve and mixing chamber which permits the main- 
tenance of any desired temperature in the troughs. When finances 
permit, the water supply of 10 of the experimental troughs will be 
additionally controlled by automatic thermostatic valves. 
Much of the long-term scientific program of the Seattle Laboratory 
had to be considerably modified during 1938 because of the lack of 
suitable facilities during the construction period. As long as the 
original Quilcene Laboratory could be used, a series of toxicity 
studies was maintained to determine the maximum nontoxic concen- 
tration of disinfectants which fish could withstand for various 
