438 SOILS: PROPERTIES AND MANAGEMENT 



Not inoculated 

 B. megatherium 

 B. fluorescens . . 

 B. proteus vulgaris 

 B. butyricus Hueppe 

 B. mycoides . . 

 B. mesentericus 



Per cent 

 3.83 

 21.56 

 9.19 

 14.7!) 

 15.55 

 23.03 

 20.60 



Lohnis l quotes Grazia e Cerza to have found that 

 Aspergillus nigrr, PeniciUiutn glaucvm, and P. brevicaule, 

 isolated from garden soil, when placed in nutrient solu- 

 tion with tricalcium phosphate, assimilated one-fifth to 

 one-third of the phosphorus in sixty days. 



There is some difference of opinion whether the solvent 

 action arising from bacterial growth is due entirely to the 

 acids that are produced by the bacteria exerting such 

 action, or whether there is also some other influence exer- 

 cised by bacteria. Stoklasa accounts for the solvent 

 action of the bacteria in his experiments by the bacterial 

 secretion of proteolytic and diastatic enzymes acting on 

 the bone meal. In opposition to this idea, Krober 2 

 maintains that the solvent action depends on the kind of 

 fermentation that the organic matter undergoes, acid fer- 

 mentation rendering the phosphates more soluble, while 

 ammoniacal fermentation results in no solvent action on 

 tricalcium phosphate and, in the presence of sufficient 

 basic material, may render the monocalcium and dical- 



1 Lohnis, F. Handbuch d. Landw. Bakteriologie, Seite 700. 

 Berlin. 1910. 



2 Krober, E. Tiber das Loslichwerden der Phosphorsaure 

 aus Wasserunloslichen Verbindungen unter der Einwirkung von 

 Bakterien und Hefen. Jour. f. Landw., Band 57, Seite 5-80. 

 1909-1910. 



