788 Holden . — Some Wound Reactions in Filicinean Petioles. 
being general. In one case only, and that of a decidedly exceptional nature, 
was any secondary growth observed. This exceptional case occurred in the 
basal part of the petiole of W oodwardia orientalis , and was apparently due 
to bacterial infection. 
The petiole showed a pronounced local dilatation in the wound area 
(PL LXXIV, Fig. 13), and on microscopic examination it was found that the 
uninjured cortical cells at the wounded surface had proliferated in a peculiar, 
irregular manner, giving rise to a well-marked intumescence (PL LXXIV, 
Fig. 14). 
The cells had, in some cases, especially at the margins of the affected area, 
grown very long without dividing, whilst the remainder had divided up by 
transverse walls at varying intervals, and the resultant daughter cells had 
also grown. The appearance of these cells was very different from that pro- 
duced by ordinary cambial division. The whole of the cells were filled with 
cytoplasm of a cloudy nature, and in addition contained minute rods, which 
were presumably the cause of the growth. Cells containing two nuclei were 
not uncommon, and in one or two of the largest cells three nuclei were 
detected (PL LXXIII, Fig. 10). 
Strasburger ( 34 ) records somewhat similar instances of cells containing 
several nuclei in the case of graftings where tissues have been injured. 
Hypertrophy as a result of infection by Bacteria is not uncommon, the 
root-nodules produced in Leguminosae, Alnus , and Myrica being typical 
instances, whilst Smith ( 27 ) has also described local swellings produced on 
the olive due to similar causes. 
Immediately below the meristematic zone there was a large patch 
of tissue several cells in diameter which had become strongly impregnated 
with tannin, this cutting off the infected cells from the general mass of 
cortical tissue (PL LXXIV, Fig. 14). 
Appearances point to this being of the nature of a protective wall since 
the rodlets were not detected in any of the cells within this zone. 
The results obtained in the basal petiolar region are precisely what 
might have been anticipated from a comparative study of the effects of 
wounding in the younger parts. As the petiole becomes absolutely set and 
mature the stimulus causing anything but the simplest form of response, 
that is, local thickening, would have to be of a very unusual character, 
a condition fulfilled in the abnormal case recorded. 
The description of the various reactions recorded has been confined to 
the results produced in the general mass of cortical parenchyma, and as the 
remaining tissues appear to each show considerable uniformity it has been 
thought preferable to deal with them separately. 
(a) The epidermis in the most freely reacting forms (e. g. Aspleninm 
Belangeri) showed a certain amount of sliding growth in the 
wound area accompanied by one or more cell-divisions, this 
