998 
Journal of Agricultural Research 
Vol. XXXI, No. 10 
of the alfalfa and sweet clover strains produced an acid reaction. 
Some of the cultures showed no change during eight weeks. Perhaps 
this was due to a failure of the organisms to grow. These data are 
shown in Table I. 
Table I .—Characteristics of nodule bacteria in milk , with various indicators , after 
five weeks at 28 ° C. 
Strain and No. 
Plain milk 
Litmus milk 
Brom-cresol purple 
milk reaction 
Reaction 
Reduction 
Sweet clover, 110, 111, 112.. 
Alfalfa, 106,107,108__ 
Alfalfa, 100, 103, 104.. 
Alfalfa, 101,102,105_ 
Clover, 121,122.. 
Serum zone... 
-do. 
.do... 
_do.. 
do 
Acid.. 
_do_ 
.do_ 
_do. 
At bottom_ 
.do_ 
_do. 
-do- 
Throughout... 
None. 
Acid. 
Do. 
No change. 
Slightly alkaline. 
Very alkaline. 
* Do. 
Do. 
Slightly alkaline. 
Very alkaline. 
Alkaline. 
No change. 
Alkaline. 
No change. 
Very alkaline. 
Clover, 123, 124, 125_ 
.do.. 
Alkaline_ 
Garden pea, 130_ 
_.do_ 
Very alkaline. 
Slight. 
Garden pea, 132.__ 
_do_ 
_Jdol.. 
None_ 
Garden pea, 131.. 
.do_ 
Throughout... 
None_ 
Vetch, 134__ 
_do_ 
Very alkaline_ 
Garden bean, 140..... 
Cowpea, 143.... 
.do.... 
None_ 
_.do_ 
.do_ 
.do_ 
.do_ 
Lima bean, 142__ 
Soy bean, 161, 164, 166.. 
Soy bean, 160,162, 163, 165. 
_do. 
_do. 
.do- 
_do.. 
_do. 
.do__ 
_do. 
-do_ 
.do. 
Most of the organisms reduced Janus green to a permanent pink 
color in from one to three weeks, as shown in Table II. Some cul¬ 
tures reduced this indicator only at the bottom, while others reduced 
it throughout. Soy-bean, cowpea, and lima-bean nodule organisms 
were least active in reducing the indicator. Three strains of soy¬ 
bean nodule organisms produced ho change within 39 days. Very 
little, if any, change in reaction was ever noted in the Janus-green 
culture. 
Table II .—Effect of the growth of the nodule bacteria on Janus-green milk {dupli¬ 
cate tubes) 
Strain and No. 
Changes produced after— 
7 days 
39 days 
Sweet clover, 110, 111, 112..._ _ _ 
Pink at bottom_ 
Pink. 
Alfalfa, 100___ 
Pink..... 
Do. 
Alfalfa, 106,107,108. ___ 
Pink at bottom_ 
Do. 
Alfalfa, 103____ 
_do... 
Pink at bottom. 
Alfalfa, 101,102,104,105__.... 
No change...___ 
Do. 
Clover, 121... ... 
Light pink__j 
Pink. 
Clover, 123_ _ ... . „ 
Whitish green.. 
Do. 
Clover, 124.... . _ __ ... 
Pink_ 
Do. 
Clover, 125. ... .. 
Light pink..... 
Do. 
Garden pea, 131..___ 
Pink.___ 
Do. 
Garden pea, 132_____ 
No change... 
Do. 
Vetch, 134__*______ 
Pink... 
Do. 
Garden bean, 140______ 
_do___ 
Do. 
Lima bean, 142____ 
No change____ 
Pink at bottom. 
Soy bean, 161, 164, 166____ 
.do_ 
No change. 
Soy bean, 160, 162, 163__ _ 
_do__ 
Pink at bottom. 
Soy bean, 165_ __ ___ 
_do___ 
Pink. 
The results obtained with litmus milk were more specific and were 
superior to those obtained with plain milk. As will be seen in Table 
I, litmus milk not only showed all the characteristics brought out by 
plain milk, but in addition showed changes in reaction and reduction. 
