1912] REY NOLDS—PARASITIZED LEAF TISSUE 37t 
of plants cultivated in the dry Sahara region. MOoLLiarD (51) 
found ‘‘nuclear protoplasmic division’? in stems attacked by 
Phytoptus. NAWASCHIN (54) described strongly hypertrophied 
cells, and enlarged nuclei with poor chromatin content, in tissues 
invaded by Plasmodiophora Brassicae. TouMEy (77) noted that 
the nucleus of a crown-gall cell becomes much enlarged and finally 
“appears as if eroded on the surface.’’ The nucleoli are very 
persistent. Under abnormal conditions the root tip of Allium 
Cepa shows enlarged cells and nuclei (some lacking nucleoli), and 
often an increased amount of chromatin, NEMEC (56) also noticed 
nuclear fragmentation in the same root tips. The nuclei in legumi- 
nous root tubercles are reported by PARATONE (62) as becoming 
amoeboid and abnormally colored; CHopAT (11), however, noted 
no great changes. 
The effects of changes of temperature upon cell structure have 
also been studied to some extent. PRILLIEUXx (65) grew seedlings 
in heated soil, and found that the nuclei became numerous and 
variable in form. They increased by fragmentation and often 
possess numerous nucleoli of various shapes and sizes. These are 
vacuolated. Nmec (57) found that nuclei assume amoeboid 
forms in lowered temperatures. SCHRAMMEN (66) found that 
abnormal nuclear division (‘“pseudomitosis”), abnormal size of 
nucleus, and abnormal mass of nucleolin and kinoplasm resulted 
from changing the temperature surrounding the growing point of 
a Vicia Faba stem. Martrucnor and Mottiarp (45, 47) give 
very detailed descriptions of abnormal nuclei produced at freezing 
temperatures, especially noting the distribution of chromatin. 
NéEmec (58a) produced multinucleated cells in the roots of Vicia 
Faba by placing them in a 1 per cent copper sulphate solution; 
upon returning them to normal conditions karyogamy took place 
and uninucleated cells were formed. GRANT (23) has reported 
upon various multinucleated cells. ANDREWS (2) found that a 
nucleus, deprived of its nucleolus can survive for a long time, 
but a new nucleolus is not formed. The influence of benzene gas 
upon cell formation was studied by BLazEK (5a), who reported 
that simultaneous nuclear division takes place, and many daughter 
nuclei are formed either with or without subsequent cell wall 
