38i 
PUBLICATIONS OP INTEREST T6 
AGRICULTURISTS. 
I.— CROSS-FERTILISATION OF PEARS.' 
A postscript to the paper on Cross-fertilisation of Cereals (Journal, 
Vol. IV. 3rd series, Part IV. 1893, p. 701) indicated some important 
results from experiments in cross -fertilisation of pears. The detailed 
account of these experiments has since been issued from the Depart- 
ment of Agriculture, Washington. The results obtained deserve a 
longer notice than was given to them in the note referred to, 
because of their practical bearing on fruit culture. 
A poor crop of pears is often due to causes over which the 
cultivator has control. Care has to be taken that the trees are in a 
healthy and vigorous condition. This is necessary not only for the 
quality but also for the quantity of the fruit. In a weak or dis- 
eased tree fewer blossoms set, and those that do set do not produce 
full sized fruits. The character of the tree also must be observed, 
and when that is not satisfactory the tree should be removed. 
Sometimes a vigorous tree has a tendency to produce only leaf-bear- 
ing branches ; this can be stopped by severe pruning. The causes of 
a poor crop are, however, generally beyond the control of the culti- 
vator. A small proportion only of the blossoms on a tree produce 
fruit. In a cluster of flowers usually one develops into a fruit, 
the others fall off early. Even before the blossom has disappeared 
a large number have fallen to the ground, and within a week or two 
some of those that have shown signs of setting also drop off. This 
is a natural operation, which prevents the tree bearing more fruits 
than it is able to perfect. Wet weather at the time when the 
anthers are fully ripe and have discharged their pollen grains pre- 
vents fertilisation. In such weather the bees and other insects, 
which are the agents in carrying the pollen grains to the stigma, 
are not about. Then a heavy shower will wash off all the free pollen 
grains and carry them to the ground. A decrease in the tempera- 
ture also is very destructive to the young fruit. A few degrees of 
frost may kill the tender growing seed, and a little more severe frost 
may fatally injure the pistil. 
The experiments of Mr. M. B. Waite show that there are con- 
ditions, hitherto scarcely suspected, which seriously affect the crops, 
and which are completely within the control of the cultivator. 
Mr. Galloway, the Chief of the Division of Vegetable Pathology 
in the United States Department of Agriculture, resolved to 
make some investigations into the influence of insects in producing 
1 The Pollination of rear Flowers. By Merton B. Waite. Pp. 86, with 
12 Plates and other Illustrations. U.S. Department of Agriculture: Washing- 
ton, 1891. 
VOL. V. T. S. — 18 C C 
