75 
of human dwellings, be they temporary or permanent. All evidence 
points to the strong need of disinfecting or destroying all the wastes from 
ourselves and other animals, destroying all excreta in which the flies 
deposit their eggs, and to do all to eliminate this factor in the spread of 
infectious and contagious diseases that heretofore has received so little 
attention. 
House Boats For BroLtocican Work. 
By Utyssrs O. Cox. 
House boats for pleasure are not at all uncommon on the Mississippi 
River, but one built and equipped for scientific purposes was, until the 
past summer, entirely unknown'on that stream, and, I am told, on most 
streams in this section of the country. Last March the writer was called 
to Minneapolis by the director of the State Zoological Survey, Professor 
Nachtrieb, and asked to suggest plans for further study of the fishes of 
the State. Among these suggestions was the one that a house boat, or 
rather, in this case, a floating laboratory, be built at Mankato to float 
down the Minnesota and Mississippi rivers, at least as far as the State 
line. 
There were a number of things to be taken into consideration. It had 
been several years since the Minnesota River had been navigated by any 
craft larger than a row boat, and just how large the floating laboratory 
could be made and still float and be manageable was a question. There 
were numerous bridges to pass, many sand and gravel bars to interfere 
and hundreds of snags to be avoided. It was finally decided to build the 
barge portion of the boat twelve feet wide, twenty-two feet long, two feet 
deep and with a flat bottom. It was estimated that a boat so built would 
draw, when empty, no more than five or six inches of water, which esti- 
mate proved later to be correct. On top of the barge was built a cabin 
twelve feet wide, fourteen feet long and six and one-half feet high. The 
roof of the cabin was covered with boards and then with canvas. At 
each end of the cabin a door opened out on the platform, which was as 
long as the width of the boat, and four feet wide. On each side of the 
