34 MICHIGAN ACADEMY OF SCIENCE. 



to secure a Hour that will make the best bread. We have vast areas of 

 practically sterile lands which under the influence of scientific agri- 

 culture might be made to support a large population. The question of 

 the disposal of sewage is an important one. Ordinarily it is thrown 

 into rivers or other watercourses, and pollutes our streams, serves as a 

 means of spreading disease, and robs our soil of its most valuable con- 

 stituents. Some experiments have been made already upon a small scale 

 and seem to indicate that certain bacteria may be used for the purpose 

 of converting the organic matter in sewage and garbage into nitrates and 

 nitrites which might be again used in fertilizing the soil. A proper solu- 

 tion of this question will lead not only to the prevention of such water 

 borne diseases as typhoid fever, but must add greatly to the productive- 

 ness of our soil. We need improved methods of making artificial stone 

 and similar building material. We have great beds of marl, but at 

 present the demand for this material is somewhat limited, and I have no 

 doubt that the time will come when this substance will be put to uses 

 much more important than any in the past. There are many other prob- 

 lems awaiting solution but time will not permit me to discuss them. 



