The Ohio Naturalist. 
[Vol. X, No. 6, 
138 
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- 
tunately 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 nature 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 occupancy. The 
attempt which has been made to study the physiological 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 1908 an examination 
of bog water and bog soils which was carried on in connection 
with the physiological ecology 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. Morrey ’s direc- 
tion, Mr. W. L. Sherman, to whom much credit is due for efficient 
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 
medium, 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 
