226 
the bulb in small drops. These superficial drops frequently contain 
mycelium, but, as in previous examinations, none could be found in any 
of the closed pockets, even by the most approved and delicate methods 
of section cutting and staining. A similar examination of tulip bulbs 
led to the same result. There is also no ground for belief thatgummo- 
sis is due to the attacks of Tylenchus. Although Beyeriuck found gum- 
mosis to be communicable in the Amygdalew , the author so far has not 
been able to produce it artificially in hyacinths. The moistened gum 
did not increase in quantity, or cause any gummy degeneration of sur¬ 
rounding tissues when put into wounds or on the cut surface of bulbs. 
From two experiments in which bulbs were kept for a long time in 
moist earth at a high temperature (30° to 37° 0.), and from considera¬ 
tions published elsewhere, the author concludes that the stinking white 
rot of the bulbs is always preceded by gummosis. In conclusion he 
says: 
The little we know to day on the subject of gum formation in bulbous plants may 
be summarized as follows: 
(1) The gum is found essentially either between the parenchyma cells of the scales 
or else between the epidermis and the parenchyma. 
(2) In the vicinity of a gum pocket the starch disappears from the parenchyma 
cells and is replaced by gum. 
(3) Those cells totally deprived of starch are not only completely alive, but may 
increase much in size and even divide tangentially. 
(4) In the cells which have died prematurely the starch remains unchanged. 
(5) Lining the greater part of the wall of cells, which surrounds the cavity, is a 
layer of gum of greater density (as shown by its yellow color) than that which occu¬ 
pies the center of the cavity. 
(6) Gummosis and the white rot are one and the same disease. 
(7) Of a parasitic cause there is no trace. 
(III.) The author describes what lie calls a rliizomania iu species'of 
Kibes, i. e ., a tendency in the branches to the formation of numerous, 
incipient, adventitious roots. These abnormal roots either do not pierce 
the bark or dry up and die as soon as they have done so, leaving only 
slight conical prominences. The result of these numerous growths is 
a hypertrophy and degeneration of various tissues, especially of the 
bark, with the formation of black or brown, rough and irregular, round¬ 
ish or elongated tumors, having a diameter many times greater than 
that of the normal branch. Main stems, robust vertical branches, and 
shoots of the first year show no trace of these tumors, and where only a 
single root was formed the author observed no pathologic change. 
These growths differ from the ordinary production of roots on branches 
in the following particulars: (1) The disposition of the roots appears to 
be entirely independent of the force of gravity or the direction of the 
light. (2) These roots also differ essentially in that their production is 
not restricted but goes on indefinitely to the formation of tumors. 
The author has been able to find in literature no mention of any anal¬ 
ogous fact. In some respects the growths suggest u witch brooms,” 
but the author could find no traces of any animal or vegetable para¬ 
site.—EiuviN F. Smith. 
