NOTES AND ABSTRACTS. 
221 
13. The experiments suggest that with an excessively hot season during the 
time of ripening, Bartlett and Easter and possibly other pears might be allowed 
to remain on the trees somewhat longer than with a normal season. 
14. For yellow Newtown, and no doubt other varieties of apples, which are 
to be stored any length of time, the necessity of quickly cooling after harvesting 
is emphasized. — R. J. L. 
Pears, Bartlett, Ripening and Storage of. By J. R. Magness (U.S. Jour. 
Agr. Res. xix. No. 10, Aug. 1920, pp. 473-500). — Physiological studies in the 
development, ripening, and storage of the Bartlett Pear show that the factors 
involved are different from those concerned in the handling of other fruits. These 
pears are not usually allowed to ripen on the tree, but are picked when they 
attain a suitable size, and then are allowed to become yellow and soft in storage. 
Under proper conditions of picking, handling, and storage, Bartlett Pears can 
be kept in good condition for two or three months. 
There is a marked and uniform increase in the total sugar in Bartlett Pears 
from early summer until after the commencement of the picking season. This 
increase is due to sucrose in the latter part of the season, and to reducing sugar 
in the earlier part of the season. A definite relationship exists between the 
total amount of sugar in ripe fruit and the temperature of the storage shed. 
Pears ripened at 70 0 F. have the highest percentage, those ripened at 40 0 F. the 
lowest, while those held at 30 0 F. for six to fourteen weeks, and then ripened at room 
temperature, are intermediate in amount of total sugar. The percentage of 
acid in the fruit decreased as the season advanced in Californian fruits, but 
increased in fruits from Oregon and Washington States. There was an increase 
in acid between time of picking and time of full ripening of the fruit at 70 0 F. 
There was much less acid in fruit ripened at 40 0 than that ripened at 70 0 F. 
The acid content of fruit left to ripen on the tree was nearly constant. There 
was a progressive reduction in the alcohol-insoluble, acid-hydrolyzable reducing 
material as the season advanced. The percentage of total solids is lowest at 
the opening of the commercial season. A short bibliography is appended. — A . B. 
Physiological Isolation by Low Temperature in Bryophyllum. By C. M. 
Child and A. W. Bellamy (Bot. Gaz. lxx. No. 4, Oct. 1920, pp. 249-267 ; 
6 figs.). — -The cooling of a zone of the petiole of the Bryophyllum leaf to a 
temperature of 2-5 to 4 0 C. for a few days is a very effective means of inducing 
the outgrowth of the leaf buds. Usually the opposite leaf, and often leaves of 
adjoining nodes, also show more or less development. The passage of fluids 
to the leaf is not appreciably interfered with by the cooled zone ; therefore 
it seems improbable that physiological isolation of the leaf can be due to the 
blocking of passage of inhibiting substances transported in these fluids. — R. J. L. 
Pickles, Chutneys, Sauces, The Making of. By Miss A. Knight, Fruit Pre- 
serving Expert (Jour. Dep. Agr., Vict. Jan. 1920, pp. 34-48). — A useful well- 
illustrated article on making pickles, sweet spiced fruit, chutney, tomato sauce, 
mushroom and walnut ketchup, aromatized vinegars, and drying herbs for home 
use.— C. H. H. 
Pine, Western, Bark-Beetle, The. By W. J. Chamberlin (U.S.A. Exp. Stn., Oregon, 
Bull. ,172, June 1920 ; 4 plates, 4 figs.). — Timber owners in Oregon are annually 
losing thousands of dollars through the depredations of timber-killing beetles. 
The most serious losses at the present time are in Jackson, Klamath, and Lake 
counties, where the loss due to the work of the Western Pine-bark beetle 
(Dendroctonus brevicomis Lee) during the past season amounted to some $200,000. 
This bulletin is a brief summary of present knowledge of the biology and 
methods for the control of this pest. — V. G. J. 
Pinus sylvestris, Fastigiate. By Prof. Henry (Irish Gard. 13, p. 161 ; 
Nov. 191 8). — Figures of several fastigiate trees of the common Scots pine are 
given with notes. Successful grafting on spruce is recorded. — F. J. C. 
Plant-Growth, The Effect of Cold in Stimulating. By Fred V. Coville 
(U.S.A. Jour. Agr. Res. xx. No. 2, Oct. 1920, pp. 151-160 ; 16 plates). — ■ 
In regions having a cold winter, native trees and shrubs become dormant in 
autumn. It is thought that this condition was brought about by the cold, and 
that new growth in the spring is due entirely to the warmer weather. The author * 
by a series of experiments finds, however, that cold tends to stimulate rather 
than to retard growth, and bases his conclusions upon the following evidence : 
1. Trees and shrubs of cold climates become dormant at the end of the grow- 
ing season without the necessity of exposure to cold weather. 
2. Trees and shrubs which are kept continuously warm during the winter 
start into growth much later in spring than those subjected to a period of chilling. 
