EIGHTH ANNUAL MEETING 



JO 



that such personal contact and exchange of ideas will con- 

 tribute much to the development and progress of the great 

 State of Illinois. 



H. B. Ward, Chairman. 



REPORT OF THE COMMITTEE 

 ON AN ECOLOGICAL SURVEY OF THE STATE 



To the Illinois Academy of Science : 



Your Committee on an Ecological Survey reports progress 

 as follows : 



In Dr. Cowles's department an interesting ecological study 

 has been made by Mr. F. T. Ullrich on the types of vegeta- 

 tion in a ravine near Chicago as affected by differences of 

 evaporation in the air and different ratios of soil moisture in 

 different parts of the ravine. The aerial evaporation was 

 determined for seventeen stations by the use of a Livingston 

 atmometer, read weekly from July 5 to October 18 (one hun- 

 dred and twelve days), and the soil moistures were ascer- 

 tained by the weighing and drying of samples of soil collected 

 weekly from three of these stations at depths of seven and a 

 half centimeters and fifteen centimeters. Mr. Ullrich's paper 

 will be published in the Bulletin of the Illinois State Labor- 

 atory of Natural History. 



Dr. Shelford has studied the effect upon fishes of the 

 wastes and liquors from the manufacture of illuminating gas, 

 with a view to learning the effect upon fishes and other useful 

 aquatic animals of a contamination of streams. The interest- 

 ing and important conclusion was reached that fishes, on en- 

 countering natural substances commonly found in water as 

 the result of decomposition of organic matter, nearly always 

 react in a way to protect themselves against such contamina- 

 tions, and thus to preserve the species ; but in the case of 

 artificial gas wastes, fishes usually swim into them without 

 turning back in the usual fashion, as if unaware of their nox- 

 ious quality, even though death may result within a few 

 minutes. This was found true of the gas liquor and also of 

 the principal dissolved gases taken separately. The gas wastes 

 contained many compounds detrimental to fishes, any one of 

 which is dangerous in itself, and no less so in combination 

 with others. 



