PAPERS ON ZOOLOGY 271 



effects of such climatic factors rather than any schemes 

 that might look well on paper. 



ACKNOWLEDGMENTS ANT> BIBLIOGRAPHY 



The writer wishes to acknowledge his indebtedness to Prof. S. A. 

 Forbes and Mr. W. P. Flint for the use of the data on the occurrence 

 of the chinch bug. 



Ball, J. 



1910. Climatological Diagrams, The Scientific Journal, Cairo, Vol. 

 IV, No. 50. 

 Huntington. E. 



1915. Civilization and Climate, New Haven. 



1919. World Power and Evolution, New Haven. 



Taylor. G. 



1914. Control of Settlement by Humidity and Temperature, Com- 

 monwealth Bureau of Meteorology, Bull. No. 14 (from 

 Huntington). 

 1919. The Settlement of Tropical Australia, Geog. Rev. S:S4-115. 



THE EFFECT OF SEWAGE AND OTHER POLLU- 



TIOX OX ANIMAL LIFE OF ER'EES 



AND STREAMS^ 



Fbank Collins Bakee, Lniteesity of Illinois 



Stream poUution may be broadly divided into two main 

 divisions: contamination by organic sewage from cities 

 and towns and by chemical wastes from factories and 

 mines. Both are inimical to life bnt the latter is es- 

 pecially fatal to animal life, causing wide stretches of 

 otherwise fertile streams to become veritable deserts. 

 Organic sewage, in a crude or highly concentrated form, 

 is also very injurious, effectually eliminating most forms 

 of life from the polluted body of water. 



The importance and seriousness of the problem of 

 stream pollution in its effect on the life of the rivers 

 and streams into which the contaminating material is 

 discharged has not, until very recently, been given the 

 attention that the subject demands. The diminishing fish 



1 Contribution from the Museum of Natural History. University of 

 Illinois, Xo. H. 



