232 EXPERIMENT STATION RECORD. 



ammonia, which is al)out 5 per cent of tlie ash-free ammonium liumate, has l)een 

 erroneously cah-ulated as organic matter. . . . 



"The (|nestion still remains whether sodic or amnionic solution, and in what 

 strength, satisfy best the re(iuirements of a solvent for humus snl)stance, regarded as 

 the sum of oi'gauic substances, decomposed or not, that are immediately available 

 for the plants." 



Studies in soil bacteriology, F. D. Chester {Delaware Sta. Rpt. 1001, pp. 60- 

 73) . — This is a preliminary report on uncompleted investigations relating mainly to 

 the study of methods of determining the number of bacteria in soil samples, the 

 numerical distribution of bacteria in soil, and the conditions (acidity, influence of 

 lime and other fertilizers, etc.) affecting the number and distribution of the soil 

 organisms. The results of pot experiments with lime and other fertilizers indicate 

 that— 



"(1) Lime diminishes the acidity of the soil as measured ])y the method of 

 Wheeler [E. S. R., 11, p. 1003], but not in the degree which would be expected. It 

 wf)uld, therefore, appear that soil acidity must in a measure be due to substances 

 which the lime does not neutralize. The basic slag slightly reduced acidity, while 

 the muriate of potash was without effect. 



"(2) The study of pots to which nothing was applied shows that the number of 

 bacteria undergoes fluctuations. In other words, death of bacteria and multiplica- 

 tion are concurrent jihenomena, and there may be gain or loss dependent upon con- 

 ditions, favorable or unfavorable, during certain intervals. 



"(3) In the pots which received no treatment a general level of bacteria was 

 maintained throughout the experiment. 



"(4) The addition of lime had a marked tendency to increase the number of bac- 

 teria in the soil, which was most marked when the larger quantities were applied. 



"(5) Neither Thomas slag nor nuiriate of potash had any appreciable effect in 

 increasing the number of bacteria in the soil." 



Elements of agricultural geology; a scientific aid to practical farming, 

 P. M(<'oNNELL [LoitcJoii: ('roi^hij Lorkirood tC' Soil, 1903, pj). X -\- 339, pih. S, figs. :?.5, 

 map 1). — This book, which is stated to represent 25 years' systematic study of the 

 subject, contains chapters on the great ice age (introductory), origin and formation 

 of soils, mineralogy of soils, iihysiography of soils, water supply, formations and 

 farming, and evolution of live stock. The statements and conclusions are based on 

 observations not only in Great Britain but in other countries, including Amerit-a. 

 As a result of his observations in New England the author supports Johnston in 

 maintaining that an intimate relation exists between rocks and soil in that region, 

 contrary to the very recently accepted views supported by Merrill and others that 

 such a relation seldom exists. Five chapters, covering 115 pages, are devoted to 

 the relation of geological formations in the British Islands to the kind of farming 

 practiced, the thesis upon which the discussion of this phase of the subject is based 

 being "that every rock formation has a soil ]>eculiar to itself, and wherever rocks 

 throughout the world have similar lithological characters the soils derived from such 

 will be similar, and with a corresponding influence on the farming thereof — provided 

 that no disturbing agencies have been at work and the materials have been allowed 

 to accumulate m situ." Special attention is also given to the evolution of live stock 

 (horses, cattle, sheep, and swine) as traced through geological remains and influenced 

 by geological formations, four chapters covering 55 pages l)eing devoted to this sub- 

 ject. In discussing this topic the author proceeds upon the theory that " similarity 

 of formations has produced similarity of breeds, just as differences of formations have 

 produced differences among breeds. The converse of this, again, is true, for we find 

 on the American continent, on the i)rairies, a region of land very similar to Eastern 

 Europe, and this similarity tends to wijie out the differences between breeds. British 

 breeds have a tendency there to lose their characteristics, and would in time, if 



