8 Ward. — Recent Researches on the Parasitism of Fungi. 
Plant-Pathology. 
Our present extensive knowledge of the pathology of plants has been 
developed chiefly from the study of two branches of botany, viz. the 
physiology of nutrition and the parasitism of the Fungi, and dates from that 
active period of research at the zenith of which appeared Kuhn’s Die 
Krankheiten der Kulturgewachse ( 100 ), 1858, and De Bary’s Morphologic 
u. Physiologie der Pilze, &c. (10), 1866, on the one hand, and Sachs’s 
Experimental Physiology ( 149 ), 1865, on the other. 
True, general treatises and papers on the diseases of plants had been 
written before these dates, of which Berkeleys papers on Vegetable 
Pathology ( 27 ), in 1854, and the works of Unger ( 187 ), 1833, Wiegmann 
( 200 ), 1839, Meyen ( 110 ), 1841, and Ratzeburg ( 140 ), 1839 and 1866, may be 
especially mentioned ; nor would full justice be done to the subject without 
reference to numerous publications on agriculture and forestry which 
appeared before 1866. Most of these earlier efforts suffered from two 
prominent deficiencies, viz. a lack of understanding of the meaning and 
significance of parasitism, and of comprehension of the fact that pathology 
is abnormal physiology. De Bary first rendered clear the former, and 
Sachs was the pioneer who cleared the way to the latter. 
During the period intervening between then and now, a considerable 
number of important treatises have appeared, of which the following may 
be deemed to have exerted the greatest influence on what is now a very 
special branch of knowledge : — 
Hartig, R., Wichtige Krankheiten d. Waldbaume ( 78 ), 1874; Die 
Zersetzungserscheinungen d. Holzer ( 79 ), 1878 ; Frank, Krankheiten d. 
Pflanzen ( 74 ), 1882 (and 2nd ed. 1894-6) ; Hartig, R., Lehrbuch d. 
Baumkrankheiten ( 77 ), 1882 (2nd ed. 1889); Sorauer, Handbuch d. Pflanzen- 
krankheiten ( 164 ) (2nd ed. 1886) ; Kirchner, Die Krankheiten, &c., unserer 
landwirtschaftlichen Kulturpflanzen ( 90 ), 1890; Prillieux, Maladies d. plantes 
agricoles, &c. ( 136 ), 1895 ; and Tubeuf, Pflanzenkrankheiten ( 172 ), 1894. 
Terminology. 
Perhaps the most striking summary of the effects of the half-century 
of work glanced at above is afforded by the number of new terms, or of 
terms with new connotations, which have been introduced into Botany. 
Here I have only time to advert to a few, but the following brief list 
will serve to remind you of a whole dictionary of names of new ideas. 
Antiseptic. Biologic forms. Toxins and anti-toxins. Form-species. 
Heteroecism. Infection-tube. Infection. Separation-cultures. Immu- 
nity. Spraying. Germ-tube. Adaptive parasites. Specialized parasitism. 
Bridging species. Pure cultures. Susceptibility. Area of infection. 
