PROGRESS IN BIOLOGICAL INQUIRIES, 1926 669 
time no entirely satisfactory method for making these surveys has been 
developed, 
It was a little late in the summer when I reached the northern waters for 
the survey. The few good days were spent in attempting to develop a system 
that would compare favorably in accuracy with the surveys of Pacific coast 
clams made by Doctor Weymouth. Apparently, in Lake Pepin at least, going 
down in a diving helmet and removing all mussels from units of the lake bottom 
to a depth of 6 or 8 inches is the most accurate method. I am not sure as yet 
just how practical it is, as I did not get entirely accustomed to working in the 
helmet we had, but I am planning to continue this work next summer. 
As regards the river-pollution investigation, Mr. Wiebe, who did the work 
under the direction of Doctor Van Oosten, will speak for himself. It is hoped 
that similar work will continue. Pollution in the Mississippi is as serious as 
in many eastern waters. 
Of the miscellaneous work of the station I want to mention that in addition 
to the pond investigation, which will be described by Doctor Davis and Mr. 
Lord, the station carried on considerable fish-cultural operations as a side line 
and does its part in carrying out the policy of the bureau in assisting local 
fish and game clubs with their problems. 
Doctor Ricu. I want to explain further in regard to this matter 
of providing fishways for dams on the west coast. The problem is 
rather complicated there, as Mr. Scofield can testify. What they are 
trying to do is to devise means for getting salmon over high dams— 
much higher than this one at Keokuk. The power companies, of 
course, are very anxious to have this thing solved, so that they can 
go ahead in the building of innumerable dams without interfering 
with the conservation of fish. The device that was tried out, and 
which was successful to a certain degree, was advertised widely in 
one of the engineering journals as solving the difficulty; but appar- 
ently the only people who had confidence in the success of this ap- 
paratus were those who devised the apparatus. However, I don’t 
think this equipment would be applicable to the Mississippi River 
dams. 
Mr. Hicerns. About a year ago the States of Minnesota and Wis- 
consin became greatly agitated over the pollution of the Mississippi 
River, and a committee from the State legislatures was appointed 
jointly, an appropriation was made by the States for carrying on 
this work, the various State health departments were brought into 
investigation, the United States Public Health Service was appealed 
to for assistance, and assistance from the Department of Commerce 
also was requested. The aid of the Bureau of Fisheries was offered 
by Secretary Hoover, and at the last moment funds were allotted for 
conducting an investigation on the pollution of fishes. I might say 
that last June the report was to be prepared and presented to the 
State legisiatures for appropriate action on January 1, so you can 
see the scope of the work was necessarily very much restricted. Mr. 
Wiebe has made as thorough a study of the survey as time permitted 
and has made a report, which will be forwarded to the State 
legislatures. 
MISSISSIPPI RIVER POLLUTION 
By A. H. WIEBE 
I shall speak on the biological survey of the upper Mississippi River. The 
object of the survey was to determine if pollution from the Twin Cities—Minne- 
apolis and St. Paul—is a factor in destroying life in this section of the river. 
The work of the survey was divided into three phases: (1) Determination of 
the absence or presence of fish; (2) a study of the bottom fauna; and (3) a 
study. of the plankton organisms. The part of the river studied extends from 
