488 JOURNAL OF THE ROYAL HORTICULTURAL SOCIETY. 
cell multiplication, which results in the formation of a tumour — the ordinary 
naked crown-gall — containing the distorted elements and showing a marked 
hyperplasia of the parenchyma. 
3. A tendency to open wounds and to early decay, and to the formation of 
daughter tumours, is produced in the plant. 
When the internodal cortex is similarly treated cell proliferation occurs, 
the elements of which are small when compared with those from which they 
have developed, because under this stimulus they remain embryonic and never 
reach maturity in size or function. 
When the crown-gall organism (hop strain) is inoculated into the leaf axils 
of young growing plants (e.g. Pelargonium, Nicotiana, Lycopersicum, Citrus, 
Ricinus, &c), the buds of which are dormant unless the top of the plant is re- 
moved, a new type of tumour develops. These tumours are covered with 
small abortive leafy shoots, flower-shoots, or if the flower anlage has been dis- 
turbed, forming twisted, fused, and fasciated shoots. 
The author explains this as follows : — The growth of the tumour disturbs 
and distorts the tissues, tearing the anlage into small fragments which are 
variously distributed and which develop on or in the tumour into organs of a 
size proportional to the size of the included fragment ; here as part of an ovary 
or anther, there as a shoot. These pathological shoots live but a short time, 
and are unable to carry on the normal activities of the plant when the other 
leaves are removed. This seems to show that fasciation is due to bacterial 
infection. 
After inoculations in places where no bud anlage are known to exist — in the 
middle of the leaves — shoots were formed. These were produced on the midribs 
or side veins of the leaves of Nicotiana, and were more numerous on young 
leaves than on older leaves. 
Thus a changed stimulus produces a more embryonic and primitive condition, 
and is a proof that the immature cell, wherever located, carries the inheritance 
of the whole organism ; and what it will finally become, as it matures, depends 
upon the stimulus withheld from it or applied to it. That is, any young cell 
may become a totipotent cell if subjected to the proper stimulus, and this 
stimulus may be either physiological, resulting in a normal structure, as when 
the top of a plant is removed, and a new top grows in its place from the ad- 
ventitious buds ; or pathological, resulting in an embryonic teratoma, as when 
a tumour-producing schizomycete is introduced into sensitive growing tissue. 
The paper is illustrated with some striking photographs of various tumours 
on Pelargonium, Ricinus communis, and Nicotiana spp. — A. B. 
Cucumber, Angular Leaf-spot Disease of. By E. F. Smith and Mary 
K. Bryan (Jour. Agr. Res. v. No. 11, Dec. 1915, pp. 465-476 ; 7 plates). — This 
disease is commonly met with on cucumbers (Cucumis sativus), and is characterized 
by the formation of numerous angular, dry, brown spots which drop out and 
give the leaves a ragged appearance. In the early stages a bacterial exudate 
collects in drops on the lower surface of the leaves and dries white. Young 
stems and petioles may be also attacked and destroyed by soft rotting. 
The causal organism is Bacterium lachrymans (n. sp.), which enters through 
the stomata. It is characterized by the presence of one to five polar flagella, 
liquefies gelatine, is a strict aerobic, and is able to form acid from saccharose and 
dextrose. On agar plates it produces round surface colonies. It is -8x1-2 /j. 
in size. 
It is suggested that Bordeaux mixture is a remedy for the disease, and 
thorough field tests should be undertaken where the disease is prevalent. 
A. B. 
Cucumber Mosaic Disease, By W. W. Gilbert. A new Infectious Mosaic 
Disease of Cucumber. By S. P. Doolittle. Experiments with the Cucumber 
Mosaic Disease. By J. C. Jagger (Phytopathology, vi. pp. 1 43-1 51, Apr. 191 6 ; 
plates). — " The cucumber mosaic disease shows most markedly on the fruits, the 
first sign being a yellowish mottling near the stem-end." These light patches 
are found later over all parts of the fruit, the darker parts being frequently raised. 
In bad cases stems and petioles are dwarfed, leaves become mottled and often 
wrinkled. It appears on the leaves with a yellowing of some part, often at the 
angle of the larger leaf veins. Badly affected branches grow slowly, blossom 
sparingly, and set only occasional fruits. A similar and probably the same, 
disease has been seen on pumpkin, squash, wild cucumber (Echinocystis lobata), 
and musk melon. It spreads rapidly and is highly infectious. 'The contagium 
passes through a Berkefeld filter. — F. J. C. 
