PREFACE TO THE ENGLISH EDITION 



[Bv H. MARSHALL WARD, D.Sc., F.R.S., F.L.S., F.R.H.S.] 



THE foundation of a science of Mycology by Berkeley, de 

 Bary, and Tulasne, pursued by Brefeld, Zopf, and others, has 

 led to a knowledge of the biology of fungi highly creditable 

 to the industrious observers who have explored this domain of 

 the vegetable kingdom ; while the gradual building up of the 

 science of plant-physiology from the days of Knight and Hales, 

 De Saussure and Boussingault, to those of Sachs and Pfeffer, 

 has placed us in possession of a vast amount of information 

 as regards normal life processes in plants. Until much more 

 recently, however, it cannot be said that we have had a science 

 of the pathology of plants i.e. the study of abnormal physio- 

 logy of anything like the same importance, in spite of the 

 splendid and progressive attempts of Berkeley, Frank, and 

 Sorauer to found one. 



In the particular department he has cultivated, Robert Hartig 

 has succeeded in founding a plant-pathology really worthy 

 of the name, and I would especially emphasize this, that his 

 researches are so thoroughly elucidative of pathological pheno- 

 mena, in that he studies not only the nature of the structural 

 lesions and of the physiological disturbances consequent on 

 these, but also the factors of the environment which throw light 

 on the question. No better illustration of this could be selected 



