1912] REYNOLDS—PARASITIZED LEAF TISSUE 369 
are formed. Starch is often abundant in certain hypertrophies. 
Bacteria were reported by DANGEARD (16, 17) as causing the 
swelling of the nucleus of Euglena, the disappearance of the 
nucleolus, and the disorganization of the chloroplasts. The effect 
on the contents of cells in the process of fermentation has been 
studied by Matrucnot and MotiiarpD (46), and Perrce (64a) has 
described the changes in the root tubercles on the bur clover. 
Cystopus candidus usually causes an unusual deposition of starch 
and formation of chlorophyll in parts usually free from these sub- 
stances, as described by EBERHARDT (19, 20). Other students, as 
GRANT SMITH (69), NoRDHAUSEN (61), W. G. SmiTH (70), WORNLE 
(94a), Hatstep (256), Mryosur (446), and Hartic (26d), have 
noted the effects of fungous invasion upon the cellulose walls, and 
the distribution of starch and of calcium oxalate. The cellulose 
walls may be thickened or dissolved, and the starch and alco 
oxalate content may be increased or decreased as determined by | 
the season, the specific invader, and the host. Warp (88) has 
found that in the wheat plant the hyphae of the invading rust do 
not seem to affect the “chlorophyll-corpuscles or the nuclei until a 
late stage of growth.’’ The leaves of the witch broom of the white 
fir are described by HARTMAN (27) as having small amounts of 
chlorophyll and starch. WO6ORNLE (94a) reports that Gymno- 
Sporangium causes excessive nuclear division and cell formation in 
pine needles. The Ustilagineae, according to STROHMEYER (75), 
cause various changes in the cells of the host, both hypertrophy 
and hyperplasy of the parenchyma occurring. MoLwiarD (48) 
described a number of cytologic changes caused by insects and 
fungi growing on various hosts. Cystopus candidus causes the cells 
to assume abnormal forms and sizes, the nuclei to enlarge, and the 
normal chlorophyll content to change. Peronospora does not 
affect its hosts in this way. Puccinia Violae on Viola silvestris 
causes the nuclei and the nucleoli to enlarge, and the power of 
division of the former to increase. The petals of Euphorbia 
Cyparissias when attacked by Uromyces scutellatus and U. praemi- 
nens show cells with enlarged nuclei and chlorophyll formation. 
The effects of various insect parasites upon the vegetative 
cells may be summed up in general thus: nuclei and nucleoli 
