228 THE PRESIDENTIAL ADDRESS. [Sess. LEXI. 
plants on the coffee estates in Ceylon were attacked by an 
epidemic which brought ruin to the cultivation, and in 
response to the appeal of the planters the Colonial Govern- 
ment appointed Ward to investigate it. There is always a 
wide gap between determination of a cause in such a case 
and the devising of an effective remedy. The first of these 
Marshall Ward succeeded in doing with absolute clearness. 
As regards the second, the planters ultimately adopted the 
radical cure of abolishing the cultivation of coffee and 
betaking themselves to other crops. That the industry 
should thus disappear was no reflection on Ward’s work. 
The fungus itself was shown by Ward to be a Uredine, and in 
working out its history many problems of infection and 
development presented themselves, and became, if not solved 
at the time, objects of attack in the future. Whether or not 
from this early association with a Uredine, the group became 
a favourite one with Marshall Ward. As you knew, itis a 
classic group, Inasmuch as it was in it that De Bary first 
traced the wonderful history of a metoxenous pleomorphous 
parasite and established the condition know as Hetercecism. 
The very last research in which Marshall Ward was engaged 
was concerned with the elucidation of problems in the group 
first suggested by his studies in Ceylon. 
It would be impossible for me in the time at my disposal 
to deal as I would wish with all the discoveries of Ward in 
the domain of the Fungi. I propose to select for mention 
to you some through which a clearly marked step forward 
was the outcome of the research. As then I was talking of 
the Uredines, I nay first of all refer to this group, though his 
most suggestive work on it was the last Ward did. 
Specialised parasitism is one of the most interesting facts 
that have become known in connection with their life 
histories. We now know that, for example, the classical 
Puccinia graminis is really an aggregate of morphologically 
different forms, but over and above this there are also 
physiologically different forms, i.e. forms which, though 
indistinguishable outwardly and structurally, yet are sharply 
distinct in their parasitism. Thus the Puccinia graminis 
of wheat does not attack rye, barley, and others of the grasses. 
This is what is meant by specialised parasitism, the forms 
being variously called adapted species, or races, biological 
