NOTES AND ABSTRACTS. 
479 
Apples, Enzymes of, and their Relation to the Ripening Process. By R. W. 
Thatcher (Jour. Agr. Res. v, pp. 103-116, Oct. 1915). — The author examined 
the juices of apples in order to discover what enzymes were active during the 
ripening process. He found no diastase (starch disappears early in the ripening 
process, and apparently the diastases also disappear), invertase, tannase, emulsin, 
esterase, oxidases, proteases, and pectinases. Only oxidases and a small quantity 
of protease and esterase were found. The discoloration of apple flesh on cutting 
is due to oxidases, and therefore quantitative measurements of the oxidases 
were made and in every case considerable quantities were found. It was found 
that keeping apples in an atmosphere of carbon-dioxide prevented changes, as 
is to be expected if oxidases are the chief agents of change in the apple fruit. 
F. J. C. 
Apples, Pears, and Quinces, Blight of. By B. S. Pickett {U.S.A. Agr. Exp. 
Stn., Illinois, Cir. No. 172, June 1914, pp. 1-10 ; 3 figs.). — The disease is caused 
by Bacillus amylovorus and frequently attacks apple, pear, quince, as well as 
mountain ash, hawthorn, and occasionally plum and apricot. The disease 
affects all parts of the tree, including blossoms, twigs, fruit, branches, trunk, 
and roots, and is particularly prevalent in southern and central Illinois. It is 
the cause of fire-blight canker in the apple (see p. 476). 
The bacteria may enter through a puncture in the epidermis or at the growing 
points of the stems. About nine days to twenty-one days after infection, the 
leaves wither, turning brown on the apple tree, black on the pear tree, and giving 
the appearance of having been scorched by fire. When the bacteria cease their 
activity, either through death or through conditions which check their growth, 
a distinct line of demarcation separates the healthy from the diseased tissue. 
To control the blight, the following measures are suggested : — All infective 
sources should be removed. These include seriously diseased apple, pear, 
quince, hawthorn, service berry and crab-apple trees within considerable 
distances of the orchards to be protected. All blighted twigs, blossoms, spurs, 
and branches should be destroyed, and the wounds on the trees disinfected with 
corrosive sublimate (1 to 1000). 
Sprays are of dubious benefit. — A. B. 
Apples, Pruning in Summer. By L. D. Batchelor and W. E. Goodspeed (U.S. A . 
Exp. Stn., Utah, Bull. 140, 14 pp. ; 2 figs.). — A study of the yield of apples during 
four years under various systems of pruning. Summer pruning gave no advan- 
tage over the usual winter methods. — E. A. Bd. 
Apples, Recognition of, by Truellis Line. By H. E. Durham (Gard, Chron. 
Nov. 18, 1916, p. 239 ; with fig.). — The name " Truellis Line " is suggested, in 
honour of its discoverer, for lines distinctly visible in a transverse central section 
of certain apples, and faintly marked or absent in others. They divide the 
parenchyma within the core area from that without, and are so variable generally, 
though constant for certain varieties, that they may be useful as a means of 
identification. A long list is given of varieties in which the character or absence 
of this line have been examined and noted. — E. A. B. 
Apples, Varieties in Ohio. By W. J. Green, Paul Thayer, and J. B. Keil (U.S. A . 
Exp. Stn., Ohio, Bull. 290, 184 pp.; 22 figs.) — Full description of varieties, with 
photographs of many. Disease susceptibility, cooking qualities, and adaptation 
to soil specially treated. — E. A. Bd. 
Aquilegia Leaf-miner. By E. N. Cory (Jour. Econ, Entom, vol. ix. pp. 419- 
424 ; Aug. 1916 ; figs.). — Phytomyza aquilegiae mines the foliage of columbines, 
the attack commencing in May. The author gives details of the life-history of 
the insect, which pupates during winter in the earth, and suggests winter cultiva- 
tion as the best means of controlling the pest. — F. J. C. 
Aristolochia Lawrenceae (Bot. Mag. t. 8650). — Argentine. Nat. Ord. Aristo- 
lochiaceae. Shrub, stem turning. Leaves, blade 3-4^ inches long and broad. 
Perianth one-lipped, yellowish white, with brown-purple veins ; mouth 5 inches * 
long, 3 inches broad at base, 2% inches above, oblong. Tube curved upwards, 
striped only, while the inner surface of the mouth is spotted with dark veins. 
G. H. 
Arsenic as a Spray for Weeds, The Effect and Fate of. By W. T. 
M'George (Jour. Agr. Res. v. No. 11, Dec. 1915, pp. 459-463). — The control 
of weeds is a very important problem, and in some experiments at the Hawaii 
Experimental Station it was found that the most economical means of weed 
