152 PLANT PATHOLOGY 



work has made no subsequent report. In returning to the historical 

 survey, we find that the borrowed nomenclature of the early patho- 

 logists rapidly fell into disuse, as the subject developed, because 

 unsuited to its needs. Yet at the present time there is no question 

 but that a vast accumulation of observation and deduction could 

 be made more available by a purification of names, due consideration 

 being shown to philology and to that curious, indefinable force to 

 which we all submit, usage. We need not adopt the scholastic terms, 

 but in some cases they might prove suggestive. 



Plant pathology is debtor to many sciences for suggestions and 

 foundation material, but the debt to human and animal medicine 

 and surgery is not large, and consists chiefly in the transfer of names, 

 with superficial reasons underlying the application. 



The next influence that swayed pathology came from a wholly 

 different quarter, and proved of more than temporary strength. In 

 the publication of the treatises on plant physiology and structure 

 by A. P. de Candolle in France, Schleiden and Sprengel'in Germany, 

 and the translations from German texts into English and other 

 languages, observations upon deviation from the normal in plant 

 life found considerable substantial basis upon which to rest. Back 

 of these were the discoveries and doctrines of Malpighi, DuHamel, 

 Hales, and Knight, of the earlier physiologists, and Treviranus, Molden- 

 hawer, and especially von Mohl, of the later physiologists of this 

 period, to give direction and strength to the course of ideas, although 

 their influence upon pathology was only indirect. I am now speaking 

 especially of the period from about 1800 to 1850. 



Another influence upon the development of the subject during 

 this time, destined to become greater than all others, was the grow- 

 ing interest in mycology. The fungi that are largely instrumental 

 in producing diseases are the very small or microscopic forms. In 

 the study of the classification of these during the first half of the 

 nineteenth century, Persoon, Nees von Essenbeck, Link, and Le- 

 veille especially deserve mention, while Sowerby, Corda, and the 

 brothers Tulasne furthermore contributed much by way of splendid 

 folio illustrations of a large number of species. The systematic 

 diagnoses of the species were chiefly the work of De Candolle, Che- 

 vallier, and Castagne in France, S. F. Gray and Greville in Great 

 Britain, Sommerfelt and Fries in Scandinavia, Link, Wallroth, and 

 Rabenhorst in Germany, and Schweinitz in America. Of these the 

 greatest influence was exerted upon systematic mycology by De 

 Candolle, Fries, and Link. Treatises on pathology became more 



Professor Byron D. Hulsted, of Rutgers College New Brunswick, N. J., as chair- 

 man, and Messrs. W. F. Swingle, L. R. Jones, Chas. E. Bessey, W. A. Kellerman, 

 Geo. F. Atkinson, and B. F. Galloway. It was to report to the botanical section 

 of the American Association for the Advancement of Science. The time of service 

 was not limited. See the Proceedings of the Madison Botanical Congress, 1893. 



