32 Report OF DEPARTMENT OF BACTERIOLOGY OF THE 
the two inoculated pots was used in the field by placing a sma!l 
portion of it in the hill with each bean seed. Several square rods 
were inoculated in this way. These soy beans produced nodules 
abundantly and from that time soy beans grown in that immediate 
vicinity have produced nodules. 
In Alabama Duggar'* used soil successfully to inoculate alfalfa in 
1897 and similar inoculation results with soy beans were obtained in 
Kansas by Otis!® in 1898. Hopkins?® at Illinois had marked results 
from pot experiments in 1901 in which he inoculated alfalfa with 
liquid from Kansas soil. An acre inoculated at the same time with 
a portion of the same soil showed marked results in favor of the 
inoculation in the spring of 1902. Later he inoculated 25 alfalfa 
fields about the State and, wherever inoculation was lacking, as 
seemed to be the case in most fields, he obtained good results from 
the inoculating soil. His contribution to the subject was the ob- 
servation that equally good results in the inoculation of alfalfa were 
apparently obtained when the soil used contained nodules of sweet 
clover (Melilotus alba) as when it came from an old alfalfa field. 
Russell and Moore! and Nash? likewise obtained equally good re- 
sults from the use of soil containing sweet clover and that contain- 
ing alfalfa nodules. 
The extent to which inoculation has become a part of the farm 
practice in this country can be judged from the fact that over 1,200 
farmers have obtained soil for inoculating alfalfa from a single com- 
mercial source in this State within the past five years. 
From the very first it was appreciated that the use of soil for 
carrying the desired bacteria from one field to another was a crude 
and inconvenient method; and investigators set about isolating Ps. 
radicicola and propagating it in pure cultures. The earliest at- 
tempt to use these cultures in the inoculation of considerable areas 
seems to have been made by Nobbe and Hiltner and their success 
was such that they put the cultures upon the market under the 
“ Duggar, J. F. Soil inoculation for leguminous plants. Ala. Agr. Exp. 
Stassbul. ‘S7ierso7 
* Otis, D. H. Soil inoculation for soy beans. Kan. Agr. Exp. Sta, 
Bul. 96, 1900. 
** Hopkins, C. G. Alfalfa on Illinois soi. Ill. Agr. Exp. Sta. Bul. 76 
oe) and Nitrogen bacteria and legumes. Bul. 94. 1904. 
7 Russell, H. L., & Moore, R. A. Inoculation experiments with alfalfa 
and soy beans. Wis. Agr. Exp. Sta. Rept. 22: 242-261. 1905. 
% Nash, C. W. Alfalfa in Maryland. Md. Agr. Exp. Sta. Bul. 118. 
1907. 
