382 Publications of Interest to Agriculturists. 
“ the fire ” or twig blight of the pear, and put the matter into the 
hands of Mr. Waite. The disease was prevented wherever the 
blossoms were effectually guarded against the visits of insects. 
It was clear that the bacteria causing this blight were carried by 
the insects from flower to flower. But it was observed as a result 
of the experiments that the exclusion of the insects from the 
flowers prevented the blossoms from setting their fruit. This 
suggested an inquiry into the conditions under which fertilisation 
took place, and experiments having this in view were instituted, 
in the spring of 1892, which have shed a new light on an important 
cause of unfruitfulness in pears and apples which had not hitherto 
been suspected by practical fruit-growers. 
The method of proceeding was to cover the flowers while they 
were yet in bud with bags of paper, cheese cloth, or nets. The 
paper bags excluded insects and pollen, the cheese cloth bags were 
nearly as efficient, while the meshes of the net, being about ten to 
the inch, permitted the entrance of pollen grains if they were carried 
from tree to tree by the wind. 
To determine the effects of the pollen from different flowers, it 
was necessary to prevent the pollen produced by the flower experi- 
mented on from falling on the stigma. This was done by cutting away 
with a pair of fine scissors the calyx, corolla, and stamens from the 
flower bud just before opening. Examination of the vertical section 
of the flower of a pear shows that this can easily be done. The calyx, 
corolla, and stamens spring from the edge of a cup, while the styles 
rise, at some distance from them, through the centre of the cup. A 
careful cutting away of the cup below the rim, where the different 
organs are given off, leaves the pistil uninjured. All the other 
flowers in the cluster were removed. A sufficient number of flowers 
being thus prepared, pollen was applied by the hand to the stigmas 
from (1) the same flower, (2) a flower from another part of the same 
branch, (3) a flower from another tree of the same variety, and (4) 
a flower of another variety. One of the experiment stations was in 
a large orchard, containing about 22,000 standard William pear- 
trees (called in America Bartletts). Not a single William blossom 
set fruit with pollen from a William flower, no matter where the 
pollen was obtained from, while a large proportion of the flowers 
crossed with other varieties did. The results were practically the 
same in the other experimental stations, except that some varieties 
were sufficiently influenced by their own pollen to produce fruit, 
though in all the cases the fruits were smaller and the seeds small 
and barren. The William is nearly, or quite, self-sterile, and so also 
are the following twenty-one other varieties which were experimented 
upon : — Anjou, Boussock, Clairgeau, Clapp’s Favourite, Columbia, 
De la Chime, Doyenne Sieulle, Easter, Gansel’s Bergamotte, Grey 
Doyenne, Howell, Jones, Lawrence, Louise Bonne de Jersey, Mount 
Yernon, Pound, Sheldon, Souvenir du Congres, Superfin, Wilder 
(Col.) Winter Nelis. A smaller number of varieties have been ob- 
served to be able more or less to fertilise themselves. These are : 
Angouleme, Box, Brockworth, Buffum, Diel, Doyenne d’Alemjon, 
