Recent Researches on the Parasitism of Fungi 1 . 
BY 
H. MARSHALL WARD, Sc.D. Cantab.; Hon. D.Sc. Victoria. 
President of the Cambridge Philosophical Society ; Fellow of Sidney Sussex College , and Hon. 
Fellow of Christ's College , Cambridge ; and Professor of Botany in the University . 
Introductory. 
T HE definition of * recent ’ must always be relative, and in the present 
connexion it refers to very late times indeed : times not only within 
the period of the lives of all of us, but in the recollection of most of us. 
For it should not be forgotten that we have not yet reached the jubilee 
of the germ-theory of disease, or that of modern pathology and mycology. 
Even if we take as our starting-point the period of Cohn’s classical 
work ( 48 ) on Empusa Muscae, 1855, and of A. Braun’s monograph ( 35 ) 
on Chytridium , 1855; of De Bary’s Untersuchungen U. d. Brandpilze ( 4 ), 
1853, and ofTulasne’s splendid Memoires sur les Ustilagin^es comp, aux 
Uredinees ( 184 ) > 1847 and 1853 — a period rich in mycological investi- 
gations — we are still only just at the jubilee of the foundation of the 
modern anatomical school of mycology. 
It was not until De Bary’s supreme classic, Recherches sur le 
developpement de quelques champignons parasites ( 5 ), in 1863, followed 
by his Morphologie u. Physiologie d. Pilze, &c. ( 7 ), in i866 r that the foun- 
dation of the parasitism of Fungi, as now understood, was established, so 
that I am well within the limits of historical truth in insisting on the 
fact that we have not yet arrived at the jubilee of the demonstration of 
parasitism and infection on a scientific basis. 
As regards bacteriology, events are even more recent, for I think I am 
right in dating the whole of the modern germ-theory of disease from 1876, 
the date of Cohn’s publication of Koch’s paper on Anthrax ( 99 ), though, as 
we shall see, the way had been paved here also by the indefatigable labours 
of earlier botanical investigators. 
But these were merely the foundations. No consistent doctrine of the 
pathology of plants, a branch of science which has now grown to enormous 
1 An address delivered before Section K, British Association, at Cambridge, on August 22, 1904. 
[Annals of Botany, Vol. XIX. No. LXXIII. January, 1905.] 
B 
