30 Transactions British Mycological Society. 



existing between the parasite and the surrounding tissues. 

 Mycology therefore must be directed towards the study of the 

 physiology of fungi as well as towards their morphology. Plant 

 pathology is essentially abnormal plant physiology, in which a 

 parasite is often the disturbing agency. Acting upon both host 

 and parasite are environmental conditions which sometimes 

 favour the one and sometimes the other. As Butler has indicated 

 in his "Fungi and Disease in Plants" these external factors are 

 often of critical importance in the establishment of disease. 

 Several mycologists are now engaged upon an intensive physio- 

 logical study of certain pathogenic fungi, and already at the 

 hands of Brown, Wiltshire, and others, results of great im- 

 portance have been obtained. For several years I have been 

 engaged upon an intensive study of Stereum purpureum, and 

 with the help of my colleagues, light is now being shed upon 

 the exact manner in which this fungus causes infection of fruit 

 trees. In the study of fungous diseases of plants, so many factors 

 are involved that it is often supremely difficult to determine 

 their relative importance, but it is certain that unless the 

 physiology of the parasite be studied in detail, no considerable 

 progress will be made in the fundamental elucidation of disease. 



The Training of Mycologists and Plant Pathologists. 



On this occasion it may perhaps be opportune to say a few 

 words about the training of mycologists and plant pathologists. 

 As regards training, it is hardly worth while to draw a dis- 

 tinction between mycology and plant pathology, for although 

 there are important differences between the two classes of work 

 in some spheres of activity, from the point of view of the men 

 who are trained to occupy technical posts of this nature in 

 various parts of the Empire, the work of most mycologists is 

 essentially plant pathology, i.e. the investigation of plant 

 diseases and their control. It is important to consider this 

 matter carefully, because in distant parts of the Empire the 

 mycologist is often a person of no mean importance; he has 

 often been the first scientific officer to be sought by the culti- 

 vator on account of disease becoming a serious menace. If the 

 mycologist sent out has been a suitable man and has been of 

 assistance to the plant industry which invoked his aid, his 

 success has often led to the formation of extensive agricultural 

 and botanical departments which have become active centres 

 of research and guidance in the many diverse branches of 

 tropical agriculture. 



In my opinion the mycologist must be essentially a botanist. 

 Just as a doctor must be thoroughly familiar with all parts of 



