428 BOTANICAL GAZETTE [JUNE 
is only a single species, but several forms or races occur adapted to certain species 
of legumes. Their slight racial characteristics may be easily broken down by 
cultivation. The results of studies on the nitrogen-fixing power of the bacteria 
are extremely interesting, showing that the supposed symbiotic relation between 
the organism and the root probably does not exist. It is rather to be regarded 
as a parasite, its nitrogen value being merely incidental to the death of the organism. 
The nitrogen is fixed by the tubercle-forming bacteria within their bodies. This 
was determined by cultures in flasks containing nutrient solutions without nitro- 
gen. There was no increase of nitrogen in the solution, but a marked increase 
in the organisms themselves. In its biology the organism is therefore considered 
a parasite. Later the plant is able to overcome the parasite and profit by the 
nitrogen which has been fixed. When grown on nitrogenous media, it was found 
that the organism lost both its power of infecting leguminous plants and its power 
of fixing nitrogen. In non-nitrogenous media both of these properties were 
retained. The failure of NoBBr’s attempts in Germany a few years ago to put 
upon the market pure cultures of this organism can probably be attributed to 
lack of recognition of this fact. As a result of these studies Moore has devised 
a method of putting up for distribution pure cultures of Pseudomonas radicicola, 
grown in nitrogen-free media and dried on cotton immersed in the culture. ese 
cultures are sent out by the U. S. Department of Agriculture together with pack- 
ages of nutrient salts to multiply the organism. The mass-culture thus obtained 
is used to inoculate the seed or the soil. Numerous reports from farmers of all 
states indicate that this method will prove successful and _practicable.s—H. 
HASSELBRING. 
WAcHTER® has endeavored to solve some of the problems arising from the 
investigations of PuRIEWITscH on the autodepletion of storage organs. The 
latter author found inorganic salt solutions to behave as isotonic sugar solutions 
in accomplishing an inhibition of autodepletion. For this fact PUuRIEWITSCH 
accounted by assuming an incipient plasmolysis of the protoplasm, and in cases 
where inhibition is accomplished by dilute salt solutions he resorted to a fluctu- 
ating permeability of the plasma for explanation. WAcHTER is apparently skep- 
tical of both explanations. For his material the author selected the onion, expect- 
ing to avoid such difficulties as are associated with the inversion of insoluble 
storage products, being able thus to deal only with diosmosing substance, which 
was supposed to be chiefly glucose in the onion. He finds, however, that glucose 
is not the chief storage product; that other not directly reducing carbohydrates 
are present in fully equal amount, and that they exosmose into water or into salt 
solution in far greater proportion than does the glucose. For this fact the author 
5 By an oversight, only a portion of this review appeared in the BOTANICAL 
GAZETTE for May, p. 371.—Eps. 
6 WAcHTER, W., Untersuchungen iiber den Austritt von Zucker aus den Zellen 
Speicherorgane von Allium Cepa und Beta vulgaris. Jahrb. Wiss. Bot. 41: 165-220. 
g. I. Igo5. 
