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shall utilize to any considerable extent the collections now 

 accumulated. This work will be necessary to the full coutirma- 

 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 tliis 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 tMo 

 years from the Illinois Eiver and from Spoon Eiver 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 

 nitrates, 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 -Inly 23, 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 tlic bottom waters of the three localities above 



