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 cf heavy soils. 
The same amounts and proportions of plant nutrients are not 
taken by 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 by 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 they were 
addressing immature minds that needed direction and a sympa¬ 
thetic attitude rather than the dry facts and abstractions cf 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 are 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 will 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 farm, 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 plants in which all city people should have 
an interest. J- H. s. 
