THE KUHNIAN PERIOD 57 



appeared in 1846. Berkeley is better known as a mycol- 

 ogist because of his numerous contributions in that field. 

 He was always interested in the practical application of 

 his knowledge, being for ten years editor of the journal 

 of the Royal Horticultural Society. 



Toward the end of this period appeared a number of 

 books on plant pathology, for the most part the maiden 

 efforts of young pathologists whose works and writings 

 were to mold and direct in many ways the phytopath- 

 ologic thought of the early part of the next period. 

 The most important were: Important diseases of forest 

 trees, 1874, 1 by Robert Hartig; Handbook of plant dis- 

 eases, 1874, 2 and Fruit tree diseases, 1879, 3 by Paul 

 Sorauer; and Diseases of plants, 1880, 4 by A. B. Frank. 

 These men and their works will be discussed under the 

 next period. 



Summarizing as for the previous periods, we may say 

 of the Kiihnian period: (1) the thought and works of 

 the time were decidedly mycologic; (2) the basis of 

 classification was now entirely etiologic. This is char- 

 acteristic of all the books on plant diseases published 

 during this period; (3) the influence of the gardener, 

 forester, and farmer was decidedly marked and was due 

 primarily to the investigations of the farmer-scientist 



1 Hartig, R.: Wichtige Krankheiten der Waldbaume, pp. I-VIII + 

 1-127, Berlin, 1874. 



2 Sorauer, P.: Handbuch der Pflanzenkrankheiten, pp. I-VIII + 

 1-406, Berlin, 1874. This is the first edition, followed later by two en- 

 larged revisions, the third in three volumes. (See footnote 1, page 100.) 



3 Sorauer, P.: Die Obstbaumkrankheiten, pp. I-VII + 1-204, 

 Berlin, 1879. 



4 Frank, A. B.: Die Krankheiten der Pflanzen, pp. I-VII + 1-844, 

 Breslau, 1880. 



