14 
variations of its food and its habits under different conditions; to 
study the bearings and consequences of its spread and increase on the 
welfare of our native fishes, and on the whole system of fresh-water 
life; to watch for evidences of local over-population by it, to be sus¬ 
pected when the carp or its competing species fall below the average 
in size and plumpness, or when epidemic diseases appear among them; 
to follow the course of events in its principal spawning grounds, 
where our own observations show that tremendous losses, amounting 
to a local extermination of the young, may occur under usual condi¬ 
tions; and to determine, by the use of numbered tags, the range of 
the wanderings of this and other fishes, and especially to learn how 
far the various species usually go from the places where they were 
hatched. We have a rare and remarkable opportunity in Illinois 
to watch the progress of a biological revolution as important to the 
life of our waters as was the Norman invasion to the life and his¬ 
tory of England. Fortunately, we have for comparison with present 
and future conditions, the materials and records of several years’ 
systematic and connected work done on the Illinois river before 
the opening of the drainage canal into Lake Michigan, and when the 
carp was but just beginning to make its presence felt as a disturber 
of the then existing order. 
I can not, within the time limits of your program, go further with 
the development of this subject, and I must content myself with 
these sample fragments of its discussion. When the results of our 
river work began to appear several years ago, a leading American 
zoologist wrote me that the Illinois promised to become very soon 
the best known—because the best studied— of any river in the world, 
and we have been at work a good deal of the time since in an ef¬ 
fort to increase still further our knowledge of that stream and the 
public appreciation of its value. In the face of the gigantic inter¬ 
ests—agricultural, industrial, commercial, and political—which are 
now mustering along its course, with huge schemes in hand for 
revolutionary operations upon its channel, its banks, and its back- 
waters, we feel that we need all the backing and assistance we can 
secure from those concerned in the preservation and development of 
our native fisheries; and no agency, I am sure, is in a position to 
give us more effective aid than this old and influential American 
Fisheries Society. Especially we shall value your suggestions both 
as to subjects deserving early investigation, and also as to practical 
measures possible and desirable on the basis of such knowledge as 
we now have or may presently acquire. 
