232 THE PRESIDENTIAL ADDRESS. [Sess. LXXr. 
water and then the determination of their several capacities, 
whether these made for health or disease in the user of the 
water containing them. But it was the kind of work in which 
Marshall Ward revelled. Such of the results as are published 
in the Reports of the Royal Society are compendious and 
thorough. With his characteristic intuition, Marshall Ward 
did not fail to follow up clues that might lead to framing of 
a general conclusion, and one of the most valuable products 
of this bacteriological work was his demonstration that light 
arrests development of the bacteria and ultimately kills them. 
This was no more than might be expected, and had indeed 
been vaguely forestated. But Marshall Ward went further, 
and by an elaborate series of experiments proved beyond 
question that the bactericidal action lay in the blue region 
of the spectrum. As a side issue the question of colour in 
bacteria in its relation to the action of light was a subject of 
investigation, and its parasolar value was demonstrated. 
The line of work initiated by this discovery Marshall Ward 
had proposed to follow up through other processes of the 
vegetable kingdom, but had not accomplished this at the 
time of his death. 
_ The references that have been made will suffice to indicate 
the extent and far-reaching character of Marshall Ward’s 
work in Mycology, and one cannot but feel assured that 
they establish his claim to be reckoned one of the great 
investigators of our time, who has not only added to the 
sum of knowledge, but opened up new avenues to further 
victories over the unknown. 
The following communications were read :— 
NOTE ON NEw DISEASE ON PICEA PUNGENS. 
By Dr. A. W. BorTHWIcK. 
The disease is caused by a fungus which attacks the buds 
and produces large, black, conical swellings in which numer- 
ous fructifications of the fungus occur. The bud is either 
immediately destroyed, or it may produce a very much 
twisted and cankered shoot which frequently dies off at an 
early period. The fungus is one of the ascomycetes, and shows 
characteristics resembling those of the genus Cucurbitaria. 
