4 o8 SCIENCE PROGRESS 



cattle, injudicious burning of the heather and the absence 

 during recent years of prolonged winter frosts. The methods 

 to be adopted for its eradication are persistent cutting and 

 spraying. The former is most effective if carried out during 

 early July and again in August. But spraying with 2*5 per 

 cent, to 5 per cent, solution of sulphuric acid, twice in the season, 

 is not only more effective, but involves an outlay which is about 

 one-third of that expended upon cutting. 



Saxton has given a brief account of the vegetation in the 

 neighbourhood of Manubic (Trans. Roy. Soc, S.A., 191 7) and 

 describes the anatomy of the leaf in two typical Savannah 

 grasses viz. Erianthns Sorghum and Digitaria sanginualis v. 

 ciliaris. Both show a very xerophytic structure, the most 

 striking feature being the prominent development of water 

 storage tissue, especially in the latter species. 



PLANT PHYSIOLOGY. By Franklin Kidd, M.A., D.Sc, St. John's 

 College, Cambridge. (Plant Physiology Committee.) 



General Outlook. — The centre of activity in plant physiological 

 research and development to-day is undoubtedly in the United 

 States of America. It can easily be seen that in the near 

 future the whole world will be faced with a very urgent 

 necessity for the extension and organisation of the science of 

 plant industry and production on a scale complementary to 

 that of the mechanical revolutions of the past century. In this, 

 as always, the game will be to those who are efficient and to 

 those who are prepared. For the wise, who remark the signs 

 of these days, the present is a time of stocktaking. In the 

 business of review and generalisation, which is leading to the 

 creation and staking out of new territory in questions of agricul- 

 tural research and plant industry, not the least concerned is the 

 plant physiologist, as the current scientific journals of different 

 countries show. The following may be cited as examples from 

 American botanical and plant physiological literature, indicating 

 the general tendency now beginning towards a vital change 

 of outlook. 



Plant Ecology and its Relation to Agriculture, by Dr. Warren 

 G. Waterman (Science, vol. xlvi. Sept. 7, 191 7, p. 223). Great 

 emphasis is laid on the fact that plant ecology largely overlaps 

 what should be the field of the plant physiologist. The 



