184 



cultivated land in Europe the use of "nitragin," or " nitro-bacterine " is 

 quite unnecessary for the growth of good crops of the ordinary legu- 

 minous plants, the soil being already well supplied with organisms of 

 the right kind for the adequate infection of the roots of the crop. 

 Failure to obtain increased returns after inoculation seems to occur 

 where the land is supplied with an excess of easily assimilated 

 nitrogenous compounds which check the growth of the nodule 

 organisms, and also on acid soils and those deficient in phosphates 

 and potash. 



Inoculation is likely to be effective upon soils poor in nitrogen, 

 especially where leguminous crops have not been grown previously, 

 and also on land which has given meagre crops of this class, with 

 roots devoid of nodules." 



W. B. BOTTOMLEY. Some effects of Nitrogen-fixing Bacteria on 

 the growth of Non-Leguminous plants. (Proc. Roy. Soc. 

 London, Ser.B, Si, 1909, n. B, 548, pp. 287-289 ; CenibL Bakt. etc. 2; 

 Abt., 25, 1909, No. 5-9, pp. 270-272 ; Abs. in Chem. Zentbl, 1909, II, 

 No. 9, p. 742). Exper. Stat. Rec., vol XXII, No. 3, Febr. 1910 

 Washington. 



The nitrogen-fixing power of Pseudomonas alone and combined 

 with Azotobacter (both obtained from root tubercles of Cycas) was 

 studied in culture experiments and in pot tests with barley, oats, 

 parsnips, and hyacinths. The results as measured by the increase 

 of nitrogen in the culture solution and by the growth of the plants 

 indicated in the author's opinion a decided fixation of nitrogen by 

 the combined cultures. 



W. B. BOTTOMLEY AND A. D. HALL. Nitrogen-fixing Bacteria and 

 Non-Leguminous Plants. - - Nat., 82, No. 2095, 218-219. 

 London, 1909. 



This is a further discussion of the reliability of the conclusions 

 drawn by Professor Bottomley on assimilation of free nitrogen by 

 Pseudomonas in association with Azotobacter. 



Prof. Bottomley states that there are four non-leguminous plants 

 possessing root tubercles which contain nitrogen-fixing organisms. 

 In all four a species or variety of Pseudomonas is present, but in 

 Cycas only is Pseudomonas found living outside the cortical cells, 

 in the algal zone, and in Cycas only is Pseudomonas found in 

 association with Azotobacter. 



