FEBRUARY 9, 1912] 
The organism producing nitrogen-fixing nodules 
on the roots of legumes has been isolated and 
cultivated since 1903; di Rossi’s contention that 
the proper organism had not been isolated prior 
to his work in 1907 appears without foundation. 
By a new technique it has been possible to stain 
the flagella of this organism. Instead of bearing 
a single polar flagellum it is supplied with several 
peritrichic flagella. The proper designation of 
this organism, therefore, is Bacillus radicicola. 
The Persistence and Vitality of Bacteria on Al- 
falfa Seed: M. J. PRUCHA. 
The seeds of the common farm crops such as 
wheat, corn, peas, alfalfa, etc., are extremely diffi- 
cult to sterilize without killing the seed. It has 
also been shown that the bacteria of disease are 
carried on beans and corn. It is important to 
know to what extent bacteria may persist on the 
seed. 
The following results were obtained from a 
quantitative and qualitative study of alfalfa seeds. 
Nineteen samples, grown and collected in 1909, 
from 11 different states, have been studied for 
two years. 
On fresh seed the germ content varied from 
16,000 to 12 per seed. With age the germ content 
decreases. A typical sample which when fresh 
had 7,780 per seed, when two years old gave 340 
bacteria per seed. 
Simultaneous platings were made from the 19 
samples and representatives of each apparent 
group were determined according to the Society 
Card. 
Of the 84 different group numbers determined, 
35 were Bacillus, 21 Bacterium, 19 Pseudomonas, 
1 Streptococcus and 8 Yeast. About one third of 
these forms were widely distributed and many of 
them very persistent on the seeds. Of the 84 
groups, 68 were chromogenic, yellow being much 
the more common. The samples from semi-arid 
regions gave especially brilliant colors. But 8 of 
the 84 groups were spore formers and the spore 
formers represent only about one fifth of the 
forms present at the end of two years. 
The reduction in numbers of bacteria, with age, 
is due to a decrease within each group, gradually 
the less numerous groups disappear. At the end 
of two years the most widely-distributed and most 
numerous group is Bact. 211.3332533—a non-spore 
former. 
This work will appear as a bulletin of the New 
York Agricultural Experiment Station, Geneva, 
N. Y. 
SCIENCE 229 
The Behavior of Pseudomonas radicicola in the 
Soil: B. M. Duecar and M. J. PRUCHA. 
This paper is in the form of a preliminary re- 
port on (1) the effects of conditions, especially 
drying, on the vitality of the germ, and (2) the 
multiplication of the germ in soil under the influ- 
ence of various factors. The results indicate that 
there are certain undetermined factors which seem 
to affect vitality after drying, yet it seems certain 
that after the rapid or sudden drying-out of soil 
cultures there remains a considerable number of 
living organisms, the existence of which may be 
determined either by the direct plate method, in- 
direct plating (after inoculation into bouillon) 
or host inoculation. When soil cultures are di- 
rectly and rapidly dried out the number of organ- 
isms found by the plate method may be no more 
than about one twentieth of those present when 
the drying began. This, however, relates to ex- 
cessive drying. Where the drying process is less 
complete, the number remaining alive is much 
greater, and the life of the germ extends over a 
considerable period of time. 
Cultures of this germ in sterile soil (clay loam) 
after five days gave about 160,000,000 organisms 
per gram, which is considerably more than the 
number found per ¢.c. in a control bouillon cul- 
ture. In certain experiments, sterile and unsterile 
soils were mixed in various proportions, and the 
mixed material thoroughly inoculated and com- 
pared with the check in sterile soil. The addition 
of the unsterile soil inhibits multiplication of the 
legume germ as the amount of unsterile soil is 
increased. 
Casein Media Adapted to Milk Analysis: S. HENRY 
AYERS. 
CASEIN AGAR 
Preparation of One Liter 
Agar Solution 
500 ¢.e. distilled 
water 
10 gm. agar 
Casein Solution 
300 ¢.c. distilled water 
10 gm. casein (Himer and Amend 
c.p. casein prepared accord- 
ing to Hammersten) 
7 c.c. normal sodium hydroxide. 
After dissolving casein make up to 
500 eubic centimeters. 
To 300 c¢.c. water (distilled) add 
10 gm. casein (Eimer and Amend 
¢.p. casein prepared accord- 
ing to Hammersten) 
and 7 c.¢e. normal sodium hydroxide. 
