SCIENTIFIC COMMITTEE. 
xxxiii 
were labelled, viz. : (i) Twigs without mildew ; (2) twigs with white 
mildew only, perithecia not formed ; (3) twigs with mature perithecia. 
" The results were as follows : 
" 1. Twigs not mildewed at the time of spraying : No mildew 
subsequently appeared. 
"2. Twigs with white mildew, but no perithecia at the time of 
spraying : No perithecia were subsequently observed, with the ex- 
ception of a very few young ones in a few cases, probably present 
at the time of spraying. The contents of these were shrivelled. 
"3. Twigs with mature perithecia present at the time of spraying : 
The perithecia contained shrivelled asci and shrivelled ascospores, 
or ascospores which, when immersed in water or dilute sugar solution 
and pressed out of the perithecia, burst within a few seconds. The 
ascospores were not discharged naturally and failed to germinate. 
" The perithecia from unsprayedbushes, used as a control, discharged 
perfectly healthy asci and ascospores, which did not burst when 
immersed in sugar solution, but sometimes burst in water after the 
lapse of a comparatively long period. Ascospores were discharged 
from these perithecia and collected on cover-glasses arranged at a 
distance of one quarter of an inch to over two inches from the peri- 
thecia. On several occasions the ascospores germinated, producing 
a short germ tube. Unsprayed twigs from other localities yielded 
similar results. 
"Twigs sent for examination from a locality where the operator 
admitted that the bushes were sprayed with a mixture incorrectly 
prepared yielded a large proportion of perithecia capable of ejecting 
spores. 
" The ejection of ascospores has been observed in December, 
January, March, and April. 
" From these results it is evident that spraying with Burgundy 
mixture was effective, not only in preventing the appearance of 
mildew, but also in destroying it when present, whether in an early 
or in an advanced stage in its life-history." 
The mixtures used were : 
Copper sulphate . 
Sodium carbonate (washing-soda) 
Soap powder 
11 oz. 
6 oz. 
6 gallons 
9i oz. 
Water 
and 
Copper sulphate . 
Sodium carbonate (washing-soda) 
Soap powder 
Water ..... 
9J oz. 
11 oz. 
12 oz. 
12 gallons. 
VOL. XLIII. 
G 
