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shall utilize to any considerable extent the collections now 
accumulated. This work will be necessary to the full confirma-. 
tion of the results of our investigation, and will also be very 
valuable in suggesting new fields for development, especially 
along experimental lines. The present provision for this work 
is quite inadequate to a prompt return for our present invest- 
ment in this department of the operations of the Station. The 
enumeration of the smaller organisms, especially under the 
higher powers of the microscope, is particularly taxing upon the 
eyes, and long-continued application is a severe strain upon the 
nerves of the plankton statistician. I believe it to be possible 
by the expenditure of a small amount of money to secure 
student aid for some of this work in such a way as to render 
promptly available a considerable portion of the now latent 
results of our plankton work. 
The sanitary analyses of the water in connection with the 
Chemical Survey of the Waters of the State have been con- 
tinued. Weekly samples have been collected through the two 
years from the Illinois River and from Spoon River on days 
when plankton examinations have been made. Similar regular 
collections were commenced in Thompson’s and Quiver Lakes 
in September and October of 1897, and have been continued 
in connection with the fortnightly plankton work. The total 
number of samples for sanitary analyses collected at the 
Station and shipped to Champaign during the two years is two 
hundred and eighty. As these analyses include the determina- 
tion of the free and albuminoid ammonia, the nitrites and 
uitrates, the chlorine, and the oxygen consumed, they will 
furnish data of great value for a comparison with those derived 
from the plankton work. 
The shipment of samples to Champaign for an analysis of 
the gases dissolved in the water was begun July 28, 1897, 
samples being sent from the surface water of the river for the 
determination of the oxygen. In August fortnightly surface 
samples from Thompson’s and (Quiver lakes were added to the 
shipments, and in November additional samples were sent from 
each of these localities for an analysis of the carbon dioxide. 
With the beginning of 1898 samples were collected from both 
the surface and the bottom waters of the three localities above 
