38 Report oF DEPARTMENT OF BACTERIOLOGY OF THE 
cess or a failure. The deciding point was not so much the 
absolute amount of hay produced, as that would vary greatly 
with different land, but was rather the feeling of the owner 
as to whether the hay produced on any plat in the second sea- 
son was sufficient to make a profitable return from the land. 
In all of these experiments except those of Messrs. Kane, 
Lyke, Nichols and Sackett and one of the experiments of 
Mr. Crandall, the fields were personally examined by a Sta- 
tion representative, usually just before time for cutting the 
hay. - . 
It will be noted that some nodules were found on plants on 
all of the check plats, with the possible exception of the two 
experiments for which this information is lacking, even though 
no inoculating soil was applied to them. ‘These experiments — 
from which data are lacking were killed out during the winter 
and before observations on this point had been recorded. This 
constant presence of a small amount of inoculation scattered 
over the check plat is in accord with the previous experiences 
recorded in Bulletin 300. It seems to be fully demonstrated 
that a small amount of inoculation is present in practically all 
fields of alfalfa but the source of this inoculation is still in 
doubt. It may be introduced by the alfalfa seed but it seems 
to be more probable that it is derived from the adaptation of 
germs which have been previously associated with some of the 
other legumes. In a considerable number of the check plats 
the amount of the inoculation was very slight indeed, showing 
only as an occasional nodule on a few plants. When present 
in such small amounts it is of no practical importance except 
as it furnishes an explanation for the frequently successful re- 
sults obtained where the growing of alfalfa was repeatedly tried 
upon the same field without intentional inoculation and finally — 
became a success. 
Inoculation was, of course, present in all of the plats to which 
inoculating soil had been applied at the rate of 200 to 300 Ibs. 
per acre; but what was really important, with the exception of 
the experiment of Dr. Emerson, this inoculation seemed to be 
present in an amount sufficient for the needs of the plant. The 
a 
