368 Marshall Ward. — On a lily -disease. 
magnificent flowers. The sunshine was intense, and the general 
temperature high ; this means rapid transpiration and energetic 
assimilation, processes by which hard, thick cellulose-walls 
are produced. The cuticle is also well developed, thick, clean, 
and continuous under such conditions ; and growth is steady, 
there being no superabundance of water, the light being bright. 
During the corresponding period of the past summer, how- 
ever, the conditions were very different. The weather was 
for weeks very wet, and cold, and dull ; this means a lower- 
ing of the rate of transpiration, and an increase of water in 
the plant ; assimilation is also less energetic, and thin, watery, 
ill-developed cellulose-walls are one result. I had abundant 
opportunities of convincing myself that the young lily-buds 
were gorged with water for hours at a time, and, in fact, many 
of them showed irregular protuberances of tissue due to the 
disturbances of growth consequent on this. In this dull, wet 
weather, moreover, respiration was going on more rapidly (in 
proportion to assimiliation) than is normally the case, and an 
increase, however slight, of the acids in the tissues may very 
well have resulted from this. Although the temperature was 
low, the turgid condition of the buds would be one cause of 
the thin and imperfect cuticle that often existed, and it seems 
not improbable that in the continued wet weather, small 
quantities of food-materials and acids in solution would dif- 
fuse to the outside. I made several attempts to determine 
this, but was unable to satisfy myself further than that the 
damp cuticle gave an acid reaction. 
But even if the liquid bathing the cuticle contained no 
food-materials, the other conditions were obviously in favour 
of the fungus, and I have no doubt the epidemic nature of the 
disease this year depended, not so much on any changed pro- 
perties of the fungus, as in alterations in the tissues of the host. 
Of course, once started, the fungus found another advantage in 
being able to develop such enormous quantities of conidia in 
the damp atmosphere, and these would be blown about in 
millions by the wind. 
Accepting De Bary’s results with Peziza Sclerotiortim , I 
