852 Report of THE HorTICULTURAL DEPARTMENT OF THE 
germination of pollen and the growth of pollen tubes were made 
in the laboratory; and in the orchard the effects of spraying 
the trees when in full bloom were observed. 
The spraying mixtures and even the lime alone prevented the 
growth of pollen in weak aqueous solutions of sugar. 
In Bordeaux mixture, 1 to 11, diluted with a weak aqueous 
sugar solution to only 200 parts in 10,000, pollen rarely germi- 
nated; 100 parts in 10,000 in some cases wholly prevented the 
germination of pollen; 50 parts in 10,000 in some cases wholly — 
and in others partly prevented the germination of pollen, and 
always much retarded and dwarfed the growth of the pollen 
tubes. Even 2 parts in 10,000 sometimes had an adverse infiu- 
ence on the germination of the pollen. . 
Where apple blossoms, in the earlier part of the blooming 
season, were hit by a spray of Bordeaux mixture combined with 
an arsenical compound, they generally failed to set fruit.. Blos- 
soms which had been open several days before they were hit 
by the spray seemed to have reached a stage where this treat- 
ment did not check the setting of. fruit. Apparently conflict- 
ing results are reconciled by a clear understanding of this point. 
There is a great difference between young blossoms and old blos- 
soms in their susceptibility to injury by spray mixtures. 
By spraying repeatedly during the blooming season, thus 
hitting the new blossoms as they opened from day to day, the 
blossoms were nearly all destroyed and as a consequence scarcely 
any fruit set. 
A number of sprayed blossoms were observed which had some 
of the spray mixture on the stigmatic surface. None of these 
set fruit. | 
During the season of 1900 the Meera under experiment were 
so free from attacks of apple scab and other fungous diseases 
that no information was gained as to whether or not such dis- 
eases may be controlled better by spraying in bloom than by 
earlier and later treatments. 
Even with trees which had a great abundance of blossoms 
Spraying but once during the blooming season decreased the 
