232 SECTIONAL ADDRESSES 



knowledge is essential for what Tansley, in a paper read to this Section in 

 this place thirty-four years ago, called ' the higher branch of ecology, i.e. 

 the detailed investigation of the functional relations of plant associations 

 to their surroundings.' However desirable and necessary the collation 

 of existing knowledge of plant distribution may be, I am certain that the 

 solution of the fundamental problems of ecology will only be achieved by 

 the use of physiological methods, and particularly by the application of 

 our knowledge of the general physiology of the cell. For edaphic factors 

 must act through the root and by the absorption of materials from the soil, 

 or the exchange of material between the soil and root ; in fact the 

 processes of respiration and salt absorption would appear to be of the first 

 importance. 



Certain aspects of mycology have much in common with physiology ; 

 indeed, that part of mycology which concerns pathogenic organisms is 

 inevitably closely linked with problems of the relation of host and parasite, 

 problems which are, in their very essence, physiological. Years ago it 

 was questioned whether the physiology of the plant physiologists was not 

 half pathology. Certainly the reverse question can be answered with 

 more assurance ; pathology is at least partly physiology, and therefore 

 the principles of general cell physiology must here also be of immense 

 importance, and an intimate acquaintance with these principles should 

 be an important part of the equipment of the experimental plant 

 pathologist. 



Perhaps no branch of botany has made such spectacular advances in 

 recent years as that of cyto-genetics. At least it has produced a nomen- 

 clature which rivals or excels the early efforts of the descriptive ecologists. 

 And just as descriptive ecology can do little more than correlate certain 

 types of vegetation with certain environments, so cytology can do little 

 more than correlate visible structures in the cell with genetical behaviour. 

 I cannot help thinking that a real insight into these problems also will only 

 come with the interpretation of cytological observations in physiological 

 terms, and that the greatest advance in the study of cytology will come with 

 the linking up of the knowledge of the cell acquired by these two lines of 

 investigation, the cytological and physiological. And it is surely a rather 

 remarkable fact, one indicating how far away we are at present from the 

 achievement of this end, that the physiologist tends to think of the cyto- 

 plasm as the essential factor in determining vital activities, while the cjrto- 

 logist almost exclusively concerns himself with the nucleus. Neither the 

 physiologist nor the cytologist appears at present to have anything but 

 the vaguest ideas of the relationship between the two, a relationship which, 

 however, we may feel sure is most intimate and fundamental to life. 



I would now like to pass on to the economic importance of cell physio- 

 logy and say a few words about its importance in applied botany. We 

 all know, but it cannot be too strongly emphasised, that botany is the pure 

 science of a great part of the most important industry of the world, agri- 

 culture, and that, like every other industry, it can only be carried on wisely 

 if its practice is based on scientific principles. Almost all branches of 

 botany are important for agriculture, but mycology, genetics, and physio- 

 logy are particularly so, and certainly physiology is not the least of these. 



