368 BOTANICAL GAZETTE [MAY 
subject we may mention that of WILFARTH and WiuM_R (89, 90), 
CRrocKER and Knicut (12), NEMEC (59), and ANDREWS (3). 
Finally, we may note that wind has been found to play an important 
part in the production of abnormalities. Such observations were 
made by HANSEN (26a) and Bruck (9g). The general subject of 
“pathological plant anatomy ”’ has been most satisfactorily reviewed 
by Kister (38), who has also published various articles upon 
various phases of the subject, but especially concerning the ana- 
tomic features of gall tissues (37). This review of papers upon 
the subject of the histologic and gross anatomic changes, though 
incomplete, will serve to show the present extent of the subject, 
and through these references the rest of the papers may be traced. 
From the following review of work upon pathologic cytology 
it will be seen that fungi, insects, poisonous substances, changes of 
temperature, and other physical forces all tend to modify the plant 
cell. 
Woron!n (93a) found that Exobasidium Vaccinii on Vaccinium 
Vitis-Idaea reduces the amount of chlorophyll, and that the red- 
colored erythrophyll takes its place in the palisade cells. Miss 
KNow Les (34) found that when peach leaves are attacked by 
Exoascus deformans the epidermal cells become rounded and have 
thickened walls, the palisade cells become nearly isodiametric, 
and the protoplasm is reduced in amount. ATKINSON (4) found 
that certain of the parenchyma cells become “very much elongated 
and curved or sinuous in form.’”’ TuBEuF (80) mentioned second- 
ary cell formation in the palisade of Populus niger in leaves attacked 
by Exoascus aureus. In the cells of Lilium candidum affected by 
a Botrytis disease, WARD (86) found that the mycelium causes a 
swelling, dissolving, and discoloring of the cellulose cell walls, 
but does not directly affect the protoplasmic parts. The same 
observer (87) described similar effects of a Botrytis disease upon 
the snowdrop. In WAKKER’s paper (84) there are occasional 
references to cytologic phenomena. In most of the hypertrophied 
parts no chlorophyll is formed. Calcium oxalate is in the form of 
masses of small crystals (‘‘Drusen’’) in the flower and leaf cells 
of Rhamnus Frangula, but is wanting usually in the parts attacked 
by Aecidium. In other cases numerous small individual crystals 
