42 BOTANICAL GAZETTE [JANUARY 
the unit is smaller; while the observations of others imply the 
non-existence of a persistent chromatin body. 
The work of OvERTON strongly supports the theory of chromo- 
some persistence. In the resting somatic nuclei of Thalictrum 
purpurascens and Calycanthus floridus the chromosomes are repre- 
sented by definite visible bodies, the prochromosomes (OVERTON 
33, 34). From his study of the nuclei in the pollen mother cells 
of Campanula grandis, Helleborus foetidus, Thalictrum purpurascens, 
and Calycanthus floridus, he draws the conclusion that the chromo- 
somes never lose their identity in either somatic or germ nuclei. 
Even on the spireme the chromosome unit is distinctly visible. 
During interkineses (OVERTON 35) of somatic mitoses progressive 
vacuolation and enlargement of the chromosomes take place, but 
the chromosome outline can always be traced. Larsacu (21) in 
working on the Cruciferae finds that the chromosomes remain as 
clearly defined in the resting condition as during mitosis. 
ROSENBERG (36), in the resting nucleus of the hybrid Drosera 
longifolia X rotundifolia, finds paired chromatic bodies that equal 
the number of somatic chromosomes. These he calls prochromo- 
somes or centers of chromosome formation. Davis (9) described 
chromatic bodies in the nuclei shortly after the last division in the 
archesporium of Oenothera gigas, which he thinks probably are 
chromatin centers or prochromosomes. 
On the other hand, the theory of nucleolar origin of chromo- 
somes does not support the view of chromosome permanence. 
The author has already referred to the work of WAGER (43) and 
Daruinc (7) describing the budding of chromosomes from the 
nucleolus. SHEPPARD (38) investigated the behavior of the nucleo- 
lus in Hyacinthus. In the spireme stage he found the nucleolus 
apparently being drawn out upon the chromatin threads by 
means of nucleolar pseudopodia connected with the chromatin 
threads. Here, as described, the chromatin does not originate 
entirely from the nucleolus. BERGHs (3) found large nucleoli in the 
somatic cells of Spirogyra which break up into bodies partly 
chromatic and partly achromatic equal to the number of chromo- 
somes. A more detailed citation of this will occur later. Miss 
Dicpy (11) states that there is no relation between the number of 
