1917.] The Fourth Indian Science Congress. cxcv 



On the Nitrogen -fixing Bacteria inside Root-galls caused by 



Eel - worms. —By M. 0. Tirunarayanan. 



Nodules caused by eel- worms, in roots of Benincasa, Momordica and 

 Must* contained bacteria. These were isolated and by the colonies ob- 

 tained on different media, stabs and streak-cultures, the peculiar motility, 

 staining reactions, and capacity to fix atmospheric nitrogen, have been 

 identified as belonging to the species of Bacillus radicicola. They flourish 



in nitrogen free-media. 



These plants have been healthy. Instead of being harmful, the 

 nematode attack is perhaps beneficial, because, through its agency, there 

 is established an association between these bacteria and the plant, and 

 the plant may profit by the presence of these bacteria in the same 

 way as Alnus Eleagnus, &c. 



Section of Geology. 

 President— Mr. C. S. Mtddlemiss. CLE. M.A., F.A.S.B. 



Geological Surrey of India. 



(Presidential Address.) 



Complexities of Archaean Geology in India. 



There is no doubt that if one impartially regards the trend of geo- 

 logical theories concerning the oldest rocks, known as the Archaeans, in 

 India, there is apt to arise a feeling of bewilderment. One gets puzzled 

 and perhaps upset by the fertility and versatility in explanation indulged 

 in by geologists when once they give their imagination a free rem in the 

 domain of these very difficult rocks. I am also bound to admit that 

 very much the same sort of bewilderment may readily take possession of 

 one when, instead of theories, one surveys the prime cause of those 

 theories, namely the rocks themselves. The science of geology, alas, does 

 not seem to get any simpler, clearer or more straightforward as it grows 

 older ! 



Here in Mysore, and one may sav in Southern India generally, there 

 are certain aspects of the Archaeans about which a great change of opin- 

 ion appears to have arisen during the last 12 years or so-as the geology 

 of to-day has gradually unfolded itself from earlier beginnings. 



One has but to refer to the beautifully executed geological map of 

 Mysore, on the scale of 1* to 8 miles, recently issued by the Mysore Geo- 

 logical Department, and to the solutions of some of the Archae an ^roWemj 

 as concisely presented in the very interesting •« Outline of the ^logical 

 History of Mysore " by Dr. Smeeth, Director of the Department of Mines 

 and Geology; and which, I believe, is the substance of his address before 

 a previous meeting of this Congress, to recognise that many geological 

 problems, regarded as delightfully simple in the old days of Indian geo- 

 logy, now bear new and startling interpretations and that ^me rock 

 terms (or the theoretical conceptions underlying them) have had to be 

 scrapped and cast into the melting pot, to emerge-something quite 



1 ^fbe a little more explicit, let me call your attention to the owe of 

 ■ocks known as the Dharwar system, one of the orig. nal . homes of J™ 

 is Mysore. In the earlier days of Indian geology (though not so tongago 

 after all) thev were described in modest terms as hornblende and chlorite 

 schists, quartz iron-ore rocks, quartzites conglomerates, etc., and the> 

 were regarded mostly as metamorphosed sediments, or -at .toast : as sucft 

 associated with epidiorites of effusive igneous origin. Th«v were sup 

 posed without question to overlie the " fundamental ei 



They were sup 



sneiss 



