156 -PLANT PATHOLOGY 



of this endlessly expansible country, but sober facts, they will do a 

 distinct service, not only to their eminent colleagues, but to the 

 whole science of plant pathology. For when important truths 

 are not accepted by the students of a science, the progress of the 

 science suffers. That this first claimant among contagious diseases 

 of plants is truly of bacterial origin is a statement as worthy of 

 acceptance as that two and two make four, without need of mental 

 reservation. 



After this digression let us glance at the general treatises on the 

 subject of pathology which went into the hands of the public dur- 

 ing the thirty years preceding 1880, for one of the indications of 

 cumulative activity and interest in scientific matters is the produc- 

 tion of handbooks. They serve as maps to show the extent of ex- 

 ploration, the direction of advancement, and especially as a record 

 of accepted knowledge, all in addition to their usefulness as prac- 

 tical reference-books for the cultivator. 



It may be stated first that essentially all treatises of this period 

 were by German authors, or reflections from German writings. 

 The one work that exerted the greatest influence was by Kiihti 

 of Lower Silesia, afterward at the University of Halle, not only 

 because it gave the latest information regarding parasitic fungi, to 

 which the work was chiefly devoted, but because the author poured 

 a hot fire of criticism into the camp of hero-worshipers, who ex- 

 tolled Schleiden and Schacht, both extensive writers upon physi- 

 ological and economic botany, and Liebig, the agricultural chemist, 

 and who, in admiration of the great and brilliant service these men 

 rendered to science and to economics, were blind to their errors 

 and to the drag upon progress which these errors imposed. He 

 decried the medieval tendency to lean upon authority, and ad- 

 vocated closer study of natural phenomena. "It is the problem 

 of the times," he says, "it is the problem, especially of the younger 

 husbandmen, to progress energetically, to unite science with prac- 

 tice, and to apply the results of the former to the improvement 

 of the latter, for personal profit as well as for the benefit of our fellow 

 men. But it is not words or phrases that will lead us to this, re- 

 sults, economically important results, must we be able to show; but 

 in order to do this, we must understand that to examine methodically, 

 see clearly, observe sharply, and interpret correctly the natural 

 laws underlying the association of phenomena, is the true fruit of 

 scientific study." l The admonition was timely and effective. The 



1 Es ist die Aufgabe der Zeit, es ist die Aufgabe, insbesondere der jtingeren 

 Landwirthe, riistig fortzuschreiten, die Wissenschaft mit dem Leben zu ver- 

 kniipfen und die Ergebnisse der ersteren auszubeuten zur Vervollkommnung 

 des letzteren, zum eigenen Vortheil wie zum Nutzen unserer Mitmenschen. Aber 

 nicht Worte und Phrascn sind es, die uns dazu fiihren, Resultate, practisch be- 

 deutsamc Resultate, miissen wir aufzeigen konnen, und um dies zu vermogen, 

 miissen wir einsehen lernen, dass methodisch untersuchen, klar sehen, scharf 



