AGKICULTUBAL BOTAJ!fT. 733 



tabulated results that the rapidity of diffusion, as observed in the series of 

 different salts, varies in nearly the same ratio as does that of adsorp- 

 tion. The results of various further experiments with different concentrations 

 of other salts in connection with ammonium chlorid are held to show that for 

 each of the former in connection with the latter a point of concentration exists, 

 corresponding to the maximum of adsorption by the roots. These facts are 

 held to explain, at least in part, some good effects on vegetation obtained by 

 using in addition to ordinary fertilizers, such substances as common salt, 

 gypsum, sulphate of manganese, etc., and to indicate the possibility of obtaining 

 larger crop returns by securing better utilization of nitrogen in the nutritive 

 solution. 



It is claimed that the absorption of either organic or mineral niti-ogen by 

 young plants does not depend immediately and alone upon the living substance, 

 but that it is In part determined by substances contained in the roots; also 

 that, all other conditions being equal, the adsorption and the activity of dif- 

 fusion are proportional to the concentration within limits. In solutions of 

 equal concentration the adsorptive power or the activity of diffusion is modi- 

 fiable by changes in the composition of the external medium, and bears a close 

 relation thereto. 



Contributions on nitrogen fixation and nutrition of Bacillus radicicola, 

 and on bacterial tests of nitrag^in and azotog'en, S. Heeke (Kisdrlet. Eozlem., 

 16 (1913), No. 3, pp. 311-322, figs. 2).— It is stated that the nitrogen binding 

 capacity of B. radicicola is increased with its greater accessibility to air, accom- 

 plished by means of either increase of surface or thinning of the layer of nutri- 

 tive liquid ; also that this c-apacity is increased by the addition of carbon com- 

 pounds and removal of the resulting products. Very small proportions, 0.0001 

 to 0.01 per cent, of iron or manganese accelerate the development of lupine and 

 serradella bacteria. Nitrogen compounds (ammonium sulphate, potassium ni- 

 trate, asparagin) favor the growth of nodule bacteria. Calcium carbonate is 

 found to be very injurious to lupine bacteria and less so to those of serradella, 

 but favorable to peas and particularly so to red clover. 



B. radicicola appeared more viable in azotogen than in nitragin. The azotogen 

 cultures proved to be purer than were those in nitragin. 



On the cross inoculation of the root tubercle bacteria upon the native and 

 tlie cultivated Legu mi nosaa, A. J. Ewaet and N. Thomson (Proc. Roy. Soc. 

 Victoria, n. ser., 25 (1912), No. 2, pp. 193-200, pi. 1, figs. 2 ) .—Experiments are 

 reported which were conducted to determine whether the bacteria from the root 

 nodules of native Legunjinosae are capable of directly infecting cultivated 

 species, such as alfalfa, peas, clover, beans, vetch, etc. Inoculation material 

 was taken from root tubercles on 5 sjiecies of native plants and cross inoculated 

 on 8 cultivated species, the experiment being performed twice during the period 

 from November, 1911, to June, 1912. 



Of SO different lots of plants, only two, both of which were clovers, showed 

 any indication of nodule development Although no nodules were present on 

 the roots of the other plants in the inoculated series, yet the plants showed 

 better growth and were larger and much stronger. Whether this was due to 

 the root nodule bacteria continuing to live in the soil and fix nitrogen outside 

 of the plants was not determined. 



The experiment is believed to confirm the conclusions of Bxihlert (E. S. R., 

 14, p. 1048) regarding the specialization of forms of Bacillus radicicola. 



The bacteria of Nebraska soil, J. J. Putnam (Lincoln, Nebr., 1913, pp. 54, 

 pis. 5). — This work was undertaken with the idea of ascertaining, if possible, 

 some of the many chemical changes taking place through the action of bacteria 

 Indigenous to Nebraska soil, special reference being giv«i to the fixation of 



