278 The Ohio Naturalist. [Vol. XIV, No. 5, 



Generally the practises of modern agriculture are advantageous 

 to the development of bacteria within the soil. 



The amount of moisture in the soil and the degree of aeration 

 are controlled by the mechanical operations of plowing, discing, 

 harrowing, and rolling. The resulting condition of moisture and 

 aeration affects the rate of increase of the soil bacteria. 



The application of manures and fertilizers and the turning 

 under of green manures produce changes in the soluble salts as 

 well as modifying the conditions of moisture and aeration. Barn- 

 yard manure contains bacteria to the extent of one-third of its 

 dry weight. Though a large percentage of bacteria in foeces are 

 dead, the application of several tons of barnyard manure per acre 

 to soils, introduces many millions of bacteria. 



Applications of lime affect the rate of development of bacteria 

 by the neutralization of acid conditions and improvement of 

 texture of heavy soils. 



The same amounts and proportions of plant nutrients are not 

 taken b}^ different crops. As this causes difference in composition 

 of the soil, there occurs an unequal change in the number and 

 character of the bacteria. A rotation of crops that includes a 

 legume is advantageous to the proper maintenance of an available 

 store of plant food constitutents and the economical use of the soil 

 humus. 



Ohio State University. 



Plant Life and Plant Uses b}^ John G. Coulter, published by 

 the American Book Company, represents a new type of elementary 

 botany for the high school. It is a very interesting book and its 

 method if intelligently followed will go far to place elementary 

 botany on a firm basis in the high school curriculum. The 

 author has presented a book that corresponds to the capacity of 

 high school children. Too often college professors who have 

 written high school texts have lost sight of the fact that the}' were 

 addressing immature minds that needed direction and a S}Tnpa- 

 thetic attitude rather than the dry facts and abstractions of a 

 science suitable for the mature college student or graduate. This 

 book followed by a course in elementary agronomy should make 

 an ideal course in what some arc now pleased to call "agriculture. " 

 If the new "elementary agriculture" now being exploited is to be 

 taught without a basis of knowledge of plants it ^\ill accomplish 

 little of value. But even an elementary knowledge of agriculture 

 based on an elementary knowledge of plants should give us a far 

 better practice on the fami, and in the garden than we have had 

 in the past. In city schools the course outlined in the book 

 might well be followed by special courses on trees, gardening and 

 household and food i^lants in which all city people should have 

 an interest. J. n. s. 



