260 IOWA ACADEMY OF SCIENCES. 



leone's observations. 



No. of Micro-organisms 

 in one CC.of water. 



Water at time of collection contained 5 



Water after standing twenty-tour hours in sterilized tlask lOo 



Water after standing two days in sterilized flask 10,500 



Water after standing three days in sterilized flask 67,000 



Water after standing four days in sterilized flask 315,000 



Water alter standing five days in sterilized flask More than one-half million 



Cramer's observations. 



Hours and days during which Number of Micro-organisms 



the water was preserved. in one CC. of water. 



hours 143 



24 hours 12,457 



3days 328,543 



8days 233,452 



17 days 17.436 



70 days 2,500 



The work along these lines on the college sewage may 

 be said to have just begun, and future experiments and 

 data will materially assist in the intelligent interpretation 

 of the results obtained during the last year. 



BIBLIOGRAPHY. 



1. Abbott, A. C— 



'i'he Principles of Bac'eiiology E43.9G 1897 



2. Adams, Julius W — 



Sewage and Drains for Populous Districts 228.53 1889 



3. Barwise, Sidney— 



The Purification of Sewage 150 13 1899 



4. Billet, Albert- 



La Morphologic etdu Developpement des Bacteriacees...289 14 1890 



5. B&ker, M. N. and Rafter, G. W.— 



Sewage Disposal of the United States 598.7. 116 1893 



6. Burton, W. K — 



Water Supply of Towns 304.257 1894 



7. Clark, D. W. and Demps-^y, G D.— 



Drainage of Lands, Towns and Buildings 351.115 1890 



8. Davis, Floyd- 



Report of Investigation of the Marshalltown Water Supply. .Paper 



9. Denipsey, G. D and Claik, D. K — 



Drainage of Lands, Towns and Buildings 351.115 1890 



10. Folwell, A. Prescott— 



Sewage,! he Designing, Conai ruction and Maintenance of Sew- 

 age Systems 372.12. f36. 1899 



11. Frauklaud, Percy and C C — 



Microorganisms in Water 



12. Gerhard, P. W.— 



Drainage and Sewage of Bu'ld'ngs 302 97 1894 



13. Iowa, Report of the S' ate Board of Health 59130 1889 



14. Iowa, Report of tbe State Board of Healih 1899 



