Overton—On the Boot Tips of Podophyllum Peltatum. 303 
constant normal phenomenon in the organization of daughter 
nuclei. He would regard the vacuoles or lacunae, which are pres¬ 
ent within the chromosomes, as being due to osmotic phenomena. 
The liquid in the vacuoles enters the chromosomes by osmosis, 
and by means of this endosomosing sap the lacunae are formed. 
In Allium Lawson observes an accumulation of the karyolymph 
within the chromosomes, appearing as minute lacunae, which in¬ 
crease in size and flow together, the chromosomes thus appearing 
vacuolated. As this karyolymph increases in amount the chromo¬ 
somes become finely divided, the chromatin finally appearing as 
a delicate reticulum suspended in the large vacuole of nuclear 
sap. According to this view, each chromosome has an enveloping 
plasmic membrane, and each chromosome, therefore, is an os¬ 
motic system, there being as many osmotic systems as there are 
chromosomes. Lawson’s view as to the origin of the chromosome 
membrane has been discussed by Farmer (’12). 
In Podophyllum I find the metaphasic and anaphasic chromo¬ 
somes apparently consisting of two distinctly stainable substances, 
which I regard as fairly good evidence that both linin and chro¬ 
matin are present. During the passage of the chromosomes to 
the poles numerous more or less irregular, transparent spots ap¬ 
pear, which I have suggested as probably due to absorption of 
liquid material that collects in droplets or masses often irregular 
in shape, the irregularities being due perhaps to the anastomosing 
of neighboring vacuoles. As stated, I look upon the chromosomes as 
osmotic systems as described by Lawson (’03, ’ll, ’12), except 
that I do not agree with him as to the origin of the chromosome 
membranes. Each chromosome absorbs liquid material from with¬ 
out, thus by a process of progressive vacuolation of the achro¬ 
matic portion of the chromosomes separating the denser chro¬ 
matic material which the chromatin supports. The chromatic 
granules thus become distributed in the linin reticulum by this 
process. I have never observed any indication of such an erosion 
of the chromosomes from without as has been described by some 
authors. The formation of vacuoles in the chromosomes thus pro¬ 
duces a spongy granular structure with numerous lacunae, finally 
giving rise to the elementary reticulate bands found in the rest¬ 
ing nucleus. 
I have described a peculiar lobed condition of the daughter 
nuclei. Gregoire (’06) figures a like condition for All ium but 
