330 SUMMARY OF CURRENT RESEARCHES RELATING TO 



A Text-book of Mycology and Plant Pathology. By John W. 

 Harshberger. 779 pp., 271 illustrations. London : J. and A. 

 Churchill. 1918. Price 15s. net. 



There is no branch of botanical study in which progress has been so 

 marked in recent years as in Mycology. Whether it be in the more exact 

 descriptions of the many forms with their complicated life-histories, in 

 the cytology of the various groups, or in the relations of fungi to other 

 organisms, knowledge has advanced and the records of successful 

 research have increased in every section of the science. There is, there- 

 fore, a constantly renewed demand for trustworthy text-books that will 

 collate the facts and present them in readable form, as has been done in 

 the present volume. In writing the text-book Dr. Harshberger has 

 drawn on his long experience as student and Professor of Mycology, and 

 has given us a work full of the most helpful guidance to a complicated 

 and difficult subject. 



The book has been divided into four parts : — I. Mycology. II. 

 General Plant Pathology. III. Special Plant Pathology. IV. Labora- 

 tory Exercises. There are, in addition, a series of appendices dealing 

 with special aspects of some particular branch of the study. Under 

 " Mycology " the more purely scientific side is dealt with — the nature 

 of fungi and the arrangement of the various groups. With them the 

 author includes an account of Bacteria and of Slime-moulds. These 

 latter, the Mycetozoa or Myxomycetes, are frequently classified as 

 animals ; but earlier botanists unhesitatingly grouped them with fungi, 

 and it is mainly fungologists who now carry on the study of these 

 organisms. Their presence in a book on fungi is further justified as 

 with them are closely associated Plasmodiophora and Spongospora, both 

 virulent diseases of plants that find their way into most text-books as 

 fungus diseases ; Spongospora is, however, omitted from Harshberger's 

 volume. Bacteria figure so largely as causing disease in plants that no 

 book on the subject is complete that does not take account of their 

 depredations. In considering the more obvious or " true " fungi, 

 Harshberger gives much useful information on their histology, chemistry, 

 and general physiology ; finally, an outline of the classification is pro- 

 vided. 



Part I. occupies almost a third of the whole volume ; the remain- 

 ing two-thirds are devoted to Plant Pathology. All the causes that 

 foster disease are considered, whether due to climate, soil, or parasite ; 

 attention is also given to abnormalities, and a welcome feature of the 

 book is the glossary of teratological terms. We would note in passing 

 the excessive number of new terms with which almost the whole 

 book bristles ; fortunately for the reader, an explanation is generally 

 forthcoming in the text. Special chapters on pathologic plant anatomy 

 describe the changes induced in the various plant tissues by the intrusion 

 of the parasite, resulting frequently in the formation of galls, witches' 

 brooms, etc. 



Part III. deals more especially with specific diseases due to fungoid 

 attack. Lists of these are given under the different hosts, arranged in 

 alphabetical order. The diseases are those prevalent in the United 

 States, but many of them are common to this country, and any one 



