15 
-earried on, and interesting improvements in special apparatus have re- 
sulted from the effort to overcome our peculiar difficulties. A paper on our’ 
plankton methods and apparatus is now in course of preparation by the 
Superintendent of the Station, Dr. C. A. Kofoid, to whom this department of 
_ the work has been assigned. 
As our work progresses and special problems are taken up for separate 
and continuous investigation, the experimental method will necessarily come 
prominently into use.. The object of biological experimentation is the inter- 
pretation of nature, and, like all intelligent experimental work, it must be: 
suggested and guided by observation and hypothesis. With us it is the 
cecological field in which experiment is especially called for. Given certain 
phenomena of local distribution, of relative abundance, of association, of 
habit, of variation, and the like, whose causes it is desirable to ascertain, it 
is incumbent upon us, by a critical and exhaustive study of the environ- 
ment to find the materials for rational hypotheses as to such causes, 
and to test such hypotheses by experimental procedure.. It is thus always: 
the field observation, or the laboratory observation. made under condi- 
tions which involve the least practicable departure from natural conditions 
actually existing, which must precede and suggest the experiment. The 
method and the general object of this work resemble thus more closely, on. 
the whole, those of the agricultural experiment station—which is, indeed, 2 
biological station under another name and devoted to a special end— 
than those of the laboratory of experimental physiology; and it is because 
ours is to be in the end and in its final objects a station for the solution,. by” 
_ experimental methods, of both special and general problems in the field of 
eecology that it was christened by its official board of control the Biological 
Experiment Station of the University. 
EQUIPMENT. 
The main features of our present equipment are the laboratory boat. and 
its contents, the steam launch, a number of. skiffs, and the apparatus and 
belongings of the Illinois State Laboratory of Natural History and of the 
biological departments of the University of Illinois, both of which are placed, 
without restriction,. at the service of the Station force. 
THE FLOATING LABORATORY. 
Our ultimate objects do not limit us to any single field,. but will eventually 
eompel us to transfer at least a part of our operations to other points for pur- 
poses of comparison and contrast. Indeed, the Illinois River work is but a 
convenient point of departure for an investigation of the whole Mississippi 
River system. These facts have made necessary for us a movable construc- 
tion of considerable size, carefully designed and thoroughly equipped for our 
work. Furthermore, the great changes of water level and the enormous ex- 
pansion of the area covered at flood in the region over which we operate, 
would make a location on shore oftentimes extremely inconvenient as working: 
quarters for our Station force. There is a. great. advantage also in a position 
