138 The Ohio Naturalist. [Vol. X, No. 6, 



which most of the diseases of the soil may be attributed. The 

 problem concerning the processes and the products of the activ- 

 ity of the injurious bacteria, and the correlated question of their 

 intimate bearing upon a decreased fertility in soils, has unfor- 

 ttmately been limited to work of a comparatively small number 

 of investigators. A glance through the literature of research in 

 soil bacteriology reveals that scarcely anything has been pub- 

 lished on the physiological effects of bacterial decomposition 

 products upon agricultural plants. 



Recent work of an experimental nattire which dealt pri- 

 marily with physiologically arid habitats and drought resistance 

 in plants (Bot. Gazette 49: 1910) has revealed to the writer that 

 the injurious products of a bacterial soil flora accumulating in 

 definite layers of soil are the leading factor to be considered in 

 the sterility of certain soils, and that these products operate 

 selectively upon invading forms striving for occupancv. The 

 attempt which has been made to stud^• the phvsiological reaction 

 of the products formed from the activity of single, isolated 

 species as well as the effects of the residual products due to mix- 

 tures of bacteria is briefly stated below. The data have been 

 tabulated and are offered now in the hope that they will be of 

 general interest, and invite other investigators to make studies 

 similar to the one here presented. A more detailed account 

 covering more extensive investigations will appear later. 



Without going into too much detail it is sufficient here to 

 point out the following: In the spring of 190S an examination 

 of bog water and bog soils which was carried on in connection 

 with the physiological ecolog}' of Cranberry Island at Buckeye 

 Lake, Ohio, disclosed that the formation of methane and other 

 gases was of bacterial origin. Agricultural plants and various 

 other cultivated varieties which were grown on Cranberry Island 

 for experimental purposes showed marked difficulty of absorp- 

 tion, soon became stunted, took on xerophilous characters, and 

 in most cases died. Through the courtesy of Prof. Morrey of the 

 Bacteriological Department of this University, the bacterial 

 examination was repeated in 1909. Under Dr. Morrev's direc- 

 tion, Mr. W. L. Sherman, to whom much credit is due for efffcient 

 aid, prepared dilution cultures from fresh samples of bog water. 

 The isolation of the various species was continued upon peat-agar 

 plates and later in test-tubes containing a beef-broth-agar 

 meditim, until from the bacterial colonies which appeared upon 

 them the pure cultures were obtained. The bacteria thus 

 isolated were tested for their toxin producing power upon a steri- 

 lized solution of bog water and peat. A number of large flasks 

 of a liter capacity containing the sterilized solution were inco- 

 ulated with the respective pure cultures. Several flasks were 

 left sterile to serve as controls, while others were inoculated with 



