5 
Harry Marshall Ward. 
Professorship of Botany in the New Forestry Department of the 
Royal Engineering College at Cooper’s Hill. Here he remained 
for ten years. Its rather utilitarian atmosphere was not very 
congenial to him. But he had at any rate an assured position, and 
a laboratory to work in. He had acquired a singularly clear style in 
lecturing, and he knew how to “ get hold ” of his students, whom 
he used to bring to Kew every week during the summer months to 
study the Arboretum. 
The Cooper’s Hill period was fruitful in some of Marshall 
Ward’s most brilliant work. He was never satisfied with mere 
morphological detail. What he always sought was the physiological 
purpose of which this was the mechanism. 1 do not doubt that he 
owed this, in some measure, to his Cambridge training. An admirable 
research on the colouring matter of Persian berries showed that 
it was produced by the decomposition of a glucoside by a ferment. 
A beautiful account of “ a Lily-disease,” contains the discovery that 
a ferment is the means by which the hyphse penetrate the cell- 
walls of the host. From this time onwards, the all-importance of 
ferment action absorbed his attention. A curious organism had 
been sent me from the Eastern counties, which was used in 
the rustic manufacture of ginger beer. I showed it one day to 
Marshall Ward, and suggested his examining it. This he did in 
the most exhaustive way, bringing to light the important fact that 
its action was due to the symbiotic work of a yeast and a bacterium. 
This is so vigorous, under favourable circumstances, that Marshall 
Ward narrowly escaped a severe accident from the blowing up of 
his apparatus. In all these researches he showed a quality which, 
I think, amounts to positive genius, and which I have not myself 
come across, at least to the same extent, in anyone but Mr. Darwin 
himself. He seemed to have the gift of compelling nature to 
reveal its most elusive secrets. When he attacked a problem it 
was impossible to predict where it would land him. There was a 
certain subtlety in the working of his mind. He often looked at 
me reproachfully when I failed to visualise what he was driving at; 
but he could not always put it into words himself. The operations 
of his mind often suggested to me his own favourite ferment 
action. 
It must, however, be confessed that this attitude had its 
limitations, and I think he sometimes failed to see the wood for the 
trees. In his investigation of the nitrogen-fixing bacteria in 
leguminous plants, though he added materially to our knowledge, 
