THE ZALLINGERIAN PERIOD 29 



with disease in plants are but abnormal structures of the 

 plants themselves resulting from, rather than the cause 

 of, the diseased condition, and this theory with respect 

 to one of the most fundamental facts of modern pathology 

 was to dominate the thought of the following period 

 (Sorauer Transl., 1914 : 50). 



The prevailing ideas regarding the etiology of diseases 

 in plants were still largely those of the ancients. Belief 

 in the r61e of the supernatural in the production of disease 

 was, of course, less marked than in the preceding period, 

 but it was still generally entertained. The causal nature 

 of such environmental factors as drought, drying winds, 

 hail, freezing, unfavorable soil, and the Uke was especially 

 put forth and emphasized. The idea of the autogenetic 

 origin of disease within the plant itself which was to pre- 

 vail during the succeeding period was taking form in the 

 minds of the contemporaries of ZaUinger, as witness the 

 statement of Ritter von Ehrenfels that "even at times the 

 tendency to bhght lies in the disposition of the tree itself— 

 a disposition which the trees obtain from the soil in 

 which they grow, from their descent, and from an unwise 

 cultivation" (Sorauer Transl., 1914 : 52). 



The practical gardeners and horticulturists were ac- 

 cumulating facts and observations on the diseases of 

 plants with which they worked and were endeavoring to 

 explain them in the light of the ancient theories and 

 superstitions with regard to such phenomena, rather 

 than in that of the scientific thought of their day. They 

 were nevertheless beginning to devise treatments for 

 these diseases and to test them through crude experi- 

 ments. Their observations, theories, and remedies they 

 set down in their books and articles on practical garden- 



