300 Bofauv (tt the Brifish Associufion. 



which produces the nodule is first ^rown for I wo weeks upon a 

 nitrog^en-free medium, cross-innocuhition is possible between 

 the organism found in root nodules of the Mimosa?, Alder, 

 Elaiag'nus, and various Papilionaceai. 



In a second paper on ' Nitrifying" Bacteria in the V'elamen of 

 certain Orchids,' he demonstrated the presence of both nitrite 

 and nitrate bacteria in the velamen cells. Dr. Ellis considered 

 the ' Taxonomic value of Cilia in Bacteriolog^y,' and showed 

 that many non-conciliated forms could, under favourable con- 

 ditions, be made to develop cilia, and that the distinction 

 between bacterium and bacillus is non-existent. He states that 

 motility, either potential or actual is a characteristic of all the 

 forms of the three divisions — Coccacecv, Bactcriacecp, and 

 Spirillaceee. 



On Monday, Botanists and Zooloi^'ists combined in a dis- 

 cussion of Fertilisation Problems, introduced by Dr. V. H. 

 Blackman, Several foreig'n visitors from the conference on 

 Hybridisation attended, and contributed to the discussion, 

 including" Profs. Johansen and Ostenfeldt. Prof. Hickson 

 pointed out that in spite of much excellent work, some of the 

 most generally accepted conclusions of cytologists, e.s^. definite 

 number of chromosomes for a given species, and chromosomes 

 as carriers of hereditary characters rested on very unsatisfactory 

 foundations. 



Tuesday morning was devoted to problems suggested by 

 the study of Seedlings, and very able papers were read by 

 Messrs. T. G. Hill, A. G. Tans'ley, A. W. Hill, and Miss 

 Thomas. In the discussion that followed the ladies figured 

 largely, and on disputed points seemed to have the best of the 

 argument. They are certainly excellent speakers, many of the 

 men being painfully deficient in comparison. Thanks to Prof. 

 Tansley, the meetings ran smoothly throughout, and were so 

 arranged that the mornings were generally given up to papers 

 and discussions, leaving the afternoons free for excursions 

 and other functions. Dr. Burtt and Mr. \V. Ingham made 

 excellent guides, and conducted large parlies to localities of 

 botanical interest. Askham Bog was visited on August 3rd. 

 The following day Castle Howard was the place selected. On 

 Monday afternoon, after a short but interesting semi-popular 

 lecture by Prof. Yapp on ' Some Impressions of South African 

 Vegetation,' and the results of observations on ' Periodicity 

 in Alg.'c,' by Miss Rich, which showed that some valuable work 

 was going on in ihr ecological studv of pond vegetation, the 



Naturalist, 



