PRESIDENTS ADDRESS. 11 



<;ou\d not form slime from particular nutrients, were incapable of 

 fixing nitrogen, but when the}' did form slime from other 

 nutrients a fixation also occurred. The presence of another 

 bacterium, itself incapable of forming slime or of fixing nitrogen, 

 increased the slime formation and the fixation of nitrogen. 

 Finally, the fixation of nitrogen was proportional to the forma- 

 tion of slime. A number of lower forms of plant life are known 

 to be capable of enriching the soil by fixing atmospheric nitrogen, 

 and among them, AzofA)bacter chroococcuni is possibly the most 

 vigorous. The Macleay Bacteriologist has confirmed the researches 

 of Beijeriiick upon this microorganism, and has also drawn 

 attention to the fact that the nodule-former of Leguminosfe is 

 quite as capable as Azotobactei- of tixing nitrogen while it is 

 vegetating in the soil. 



Three pupils availed themselves of the facilities afforded by the 

 Society's laboratory, and received instruction in certain branches 

 of bacteriology. Dr. Greig-Smith is at present in Europe, on 

 leave, familiarising himself with the recent advances in bacterio- 

 logical science. 



During the past twelve months Mr. H. I. Jensen, Macleay 

 Fellow in Geology, has been continuing his work on the alkaline 

 rocks of Eastern Australia. Early last year he completed the 

 petrological investigation of the specimens collected in the War- 

 rumbungle Mountains during the preceding year. He also visited 

 Queensland to make some final observations in the field prior to 

 the publication of his paper on the Geology of the Volcanic Area 

 of the Eist Moreton and Wide Ba}'^ Districts, Queensland. On 

 this expedition he discovered another area of glaucophane schists 

 to the north of the Conandale Range and west of the Blackall 

 Range in the Mary River valley. In May last year he was 

 granted leave of absence to visit Samoa to study the geological 

 featur-'S of the eruption in progress on the island of Savaii. 

 After writing up his paper on Samoa and investigating the rocks 

 collected in the islands, he resumed his work on the Australian 

 alkaline rocks. Mr. Jensen commenced field woik in the Nande- 

 war Mountains, starting out from Narrabri; having examined 

 the geology of this district and made a large collection of speci- 



