BOTANY: LIP MAN AND WAY NICK 
233 
fungi growing on mannite, beef, and synthetic agar, the determination of the 
soils ammonia and nitrate producing powers, of their nitrogen fixing powers, 
and of the isolation and study of the nitrogen fixing organisms found. In this 
preliminary note, we give merely a brief general statement anent our findings 
and reserve for another paper the more detailed discussion of the results 
obtained. 
Bacterial Counts. — In the surface soil from the wooded part of the island, as 
many as a million organisms per gram were found when beef agar was used 
as a medium. Less than half as many organisms developed on synthetic 
agar and only about T V as many on mannite agar. In the subsoil from the 
same spot, there were approximately r V as many organisms developing on 
beef agar as on the surf ace soil and of synthetic agar the corresponding number 
was about T V that of the surface soil on beef agar and less than \ that on syn- 
thetic agar. The subsoil developed only one organism per gram on mannite 
agar. 
In the highly calcareous sand free from vegetation, there were only about 
8000 to 9000 organisms per gram of material on both beef and synthetic agar 
and only T V as many on mannite agar. 
Nitrogen Transforming Powers of the Soils. — Both soil and subsoil from the 
wooded part of the island show powers of producing ammonia from dried blood 
nitrogen about equal to those of a poor sandy soil. The calcareous sand which, 
as has been observed above, contains relatively few organisms, possesses, 
nevertheless, a power of producing ammonia about three-quarters as great as 
that of the other soil material. 
As regards nitrifying power, all the soils seem to be very feeble, if indeed they 
possess any such power appreciably. The amount of nitrate produced by the 
subsoil of the wooded part of the island seems to be above the limit of error, 
but, curiously enough, the surface soil produces no nitrate from sulphate of 
ammonia. The calcareous sand appears to produce a small quantity of nitrate 
from sulphate of ammonia, but the amount so formed may be within the limit 
of error. From the small amount of nitrogen which the soil itself contains, 
which in no case attains 0.01%, all of the samples seem to be powerless to pro- 
duce nitrate. Dried blood in the quantities used seems to be no more satisfac- 
tory than sulphate of ammonia. These facts make possible some interesting 
speculation as to the nitrogen nutrition of the plants growing on the island, 
which we shall discuss in a future paper. 
Nitrogen Fixing Powers and Organisms. — Perhaps the most interesting re- 
sults obtained in these studies were those on the nitrogen fixing powers and 
organisms of the soil materials in question. All the samples gave characteris- 
tic Azotobacter films in mannite solution, the surface soil from the wooded 
land giving the heaviest film and the characteristic deep black pigment forma- 
tion usually ascribed to A. chroococcum. The subsoil from the wooded land 
and the calcareous sand produced thin discontinuous films and little or no 
pigment. All the films, on microscopic examination, showed typical Azoto- 
