3^4 



NATURE 



1 1, I'd I 



in ,..,. 'n>c 



fixation of II -on, and is still 



far from h. ■ > ., notably azoto- 



bacter, can take up gaseous uiliogcii and »ynthc»i«c 

 protein, nuclcin, &c., without any materials save only 

 sugar and various mineral - " ' 'i' organisms occur in 



most soils, and it is onl> to inoculate small 



quantities of soil into a v untaining the sugar, 



phosphates, potassium and other salts, but no nitrogen 

 compounds, for development to take place and nitrogen 

 fixation to occur. The chemistry of the process is un- 

 known J investigation, so far, has been confined almost 

 entirely to morphological work and to the ofTect of various 

 conditions on the process. Mtssrs. C. Hoffmann and 

 B. W. Hammer, of the University of \Visconsin Agri- 

 cultural Experiment Station, have recently (Research 

 Bulletin la) repeated and extended some of these observa- 

 tions. They find the best sugars are mannite and lactose, 

 but it is not desirable to have too much. Similarly, there 

 is no advantage in having too much calcium carbonate, 

 although some is needed. In one respect these authors 

 differ from previous investigators ; on analysing the dry 

 azotobacter cells they obtained a protein content of 17-75 " 

 per cent, only, .against 80 per cent, found by Gerlach and 

 Vogel and 70-6 per cent, by Stoklasa. The cause of the 

 difference is not clear, but may perhaps be ascribed to the 

 slime that invariably surrounds the organism without being 

 an integral part of it, and that is only removed with great 

 difficulty. 



Mow far azotobacter is active in the soil is difficult to 

 determine, because there is an opposite process, the liber.i- 

 tion of gaseous nitrogen from protein, and also, under 

 anwrobic conditions, from nitrates, also brought about by 

 bacteria. But it has been shown by Koch that the addi- 

 tion of sugar to soil some months before the seed was 

 sown led to an increase in crop by increasing nitrogen 

 fixation, although if applied direct to the crop it produced 

 harmful results. These facts are attracting much atten- 

 tion in sugar-producing countries, and it has been shown 

 that waste molasses, which cannot profitably be sold, gives 

 useful increases in crop when applied as manure some 

 weeks before planting, especially on light soils. S. S. 

 Peck, of the Hawaiian Sugar Planters' Experiment Station 

 (Bulletin 34), has studied the two changes, nitrogen fixa- 

 tion and denitrification, and confirms the general results 

 already obtained ; molasses applied before planting stimu- 

 lates nitrogen fixation, but applied to the growing plant it 

 does harm by causing loss of nitrate or diminished 

 nitrification. 



He also confirms some recent work of Russell and 

 Hutchinson, and finds that numbers of protozoa harmful to 

 bacteria occur in soil — he found amoebae, paramecium, and 

 others — all of which can be destroyed by moderate heat or 

 antiseptics like carbon disulphide. Partial sterilisation of 

 the soil is being studied in several directions. The Journal 

 of Agriculture of South Australia states that farmers there 

 have long recognised the advantage of burning the 

 stubbles, and thus heating the soil ; investigations are in 

 hand at the Roseworthy Agricultural College to study the 

 problem from this new point of view. An apparatus for 

 soil sterilisation suitable for gardeners is described in The 

 Journal of the Department of Agriculture of Victoria, 

 whic-h is similar in principle to some that are working in 

 England. The Scientific American recently gave an 

 account of methods proposed in the United States. 



.■\lthough nitrates are invaluable in the soil, an excess 

 is injurious, because it causes plasmolysis. Dr. Headden, 

 of the Colorado Agricultural College Experiment Station 

 f Bulletins 155 and 160), reports analyses of soils in 

 Colorado containing such e.xcessive amounts of nitrates 

 that they were sterile. He thinks their formation can be 

 explained only as due to bacteria ; he supposed that 

 nitrogen fixation has gone on to an excessive degree, and 

 has thus led to disastrous consequences. Further work 

 on these soils will be awaited with interest. 



The factors determining soil fertility are slowlv being 

 disentangled, but they are far from being fullv known, and 

 therefore investigations of cases of infertilitv are of con- 

 siderable scientific interest, besides being' of technical 

 importance. Such a case is afforded by the scouring 

 NO. 2167, VOL. 86] 



.j: I u. 



p- - -if Somertct, now bein;: 



• ), of the l'nivtr<»ity ol 



f -irict* of the Lower L 



diarrha'a or " scouring " in cattle fed on 

 obvious explanation is forthmming, no poi-^ 

 are found, nor does the 1 .fa pure w.ii'.: ^u;'; 



obviate the trouble. Mr. ' i> has. in The Joun 



of the Hoard of Agricullun - " -'d the m- 



tacts, and adduces strong . w that 1 



physical condition of the soil i^ .. ng factor, ti. 



peculiar conditions obtaining on the Lower Lias, but n 

 on the adjacent alluvium and Inferior Oolite, being favou: 

 able to the factor actually causing the disease. Exp*!, 

 mental work on this subject is necessarily slow ai ! 

 tedious, but, in view of its in:: it is much to ' 



hoped that Mr. Gimingham ■.' ■ to continue t: 



work on the sound li'"-- <•" ^v' js begun. 



The phenomena of -n and deflocculation in sr 



have been much in. i, but are far from be: 



worked out. E. E. Vit-a has recently summarised (Joun 

 of the Franklin Institute) the present position of <• 

 knowledge, and has slwiwn that a marked infli. 

 exerrisfd by impurities present in the wat'-r in \\ 

 su.»pensions are madp for experimental purposes, li 

 siders it probable that in absolutely pure water only a 

 medium degree of permanence would be attained. In his 

 view, any material can be suspended in water, flocculated, 

 and deflocculated, if it can be got in a sufficiently fine 

 stale. E. J. RussEti- 



.\fl'SErM WORK 7.V ISDIA AND AFRICA. 

 A CCORDING to the report of the Natural Hist..: . 

 •^ Section, the year 1909-10 was an important one in 

 the development of the Indian Museum, Calcutta, as it 

 witnessed not only a reorganisation of the staff of that 

 section, but likewise the passing of an Act to give greater 

 independence to the constituent sections in the matter of 

 scientific and educational work, and also to permit the 

 respective chiefs of the same to become ex officio members 

 of the board of trustees. As a result of the new regula- 

 tions, it will be possible to separate the archaeological 

 from the zoological section, and to place the former under 

 the control of the director of the .Archaeological Survey. 

 Among the additions during the year, attention is directed 

 to the cast of a susu, or river-dolphin, from the Hughli. 



The report on the fishes collected by the Golden Crown 

 is continued, by Messrs. Annandale and Jenkins, in No. i 

 of the third volume of the Memoirs of the Indian 

 Museum, these contributions including a supplementary 

 note on the rays, together with accounts of the 

 Plectognathi, Pediculati, and flat-fishes. As the collection 

 of sharks made by the Golden Croivn was relatively small, 

 the consideration of that group is postponed. The teleo- 

 stean collection, on the other hand, is so extensive that its 

 description in an adequate manner will practically mean 

 a revolution in our ideas of the Indian marine fish-fauna. 

 In the present contribution three small and compact 

 groups, to which the additions are comparatively few, 

 have been selected for treatment. 



From among nine papers on various groups of inverte- 

 brates in the fourth part of vol. v. of the Records of the 

 Indian Museum it must suffice to refer to some interest- 

 ing information, by Messrs. Henderson and Mathai, on 

 the occurrence of dimorphism in certain fresh-water 

 prawns of the genus Pal.nemon. In many, if not all, the 

 species two forms of adult males occur, namely, a normal 

 type of relatively large size, with well-developed nipping- 

 claws, and a generally smaller type, with the same claws 

 no bigger than in females. .Among certain other decapods 

 in which a similar dimorphism obtains, the two phases 

 are recurrent, and severally represent the breeding and 

 non-breeding conditions ; but, so far as the authors of the 

 paper could ascertain, this does not appear to be the case 

 with the Indian Palgemons. 



The classification of the anopheline mosquitoes of India 

 forms the subject of No. 5 (it may be noted that " part " 

 and " No." are respectively used in the two issues) of 

 vol. iv. of the serial last quoted. The chainges proposed 

 are of a radical character, the author. Major S. P. James, 

 refusing to admit that any of the species are referable to 

 the typical .Anopheles. The Indian members of the group 



