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Schwarz (1892) describes and figures “Chromatinkugeln” in certain 
resting nuelei of Vicia faba, Lupinus luteus and Hyadnthus orientalis. 
Later in the same year Rosen (1892) distinguishes in vegetative nuelei 
of Scilla sibirica two kinds of “Kernkörperchen”, the “Eunucleolen” 
and the “Pseudonucleolen”. He shows that the substance of the latter 
is the same as that of the chromatin. 
Zacharias (1895) describes “Nebennucleolen” or “Pseudonucleolen” 
in Cucurbita Pepo. He even observed these bodies in the nuelei of living 
hair cells. He States that they are chiefly distributed about the peri- 
phery of the nucleus and that they stain blue or violet with “Jodgrün 
und Diamantfuchsin” while the nucleoles stain red. He concludes that 
these bodies are “Nucleinkörper”. 
Rosenberg (1904), was the first to discover that in Capselia, Zostera, 
and Calendula the nuniber of these bodies is the same as that of the long 
known chromosomes of the division figures; that is the chromosomes 
are in reality represented in the resting nuelei by definite chromatic 
masses, the “pseudo-uucleoles”. Overton (1905) proposed the term 
“prochromosonies” for the similar chroniatin bodies which he found 
in the resting nuelei of the somatic cells of Thalictrum purpurascens and 
Calycanthus floridus, and which, as he points out, are not only too large 
to be considered as mere knots of the reticulum, but are of the same 
number as the chromosomes. He finds that each chromosome is repre- 
sented by a definite center of chromatin material, the prochromosome, 
which enlarges directly into the chromosome of the prophases. These 
are usually much smaller than the chromosomes of the dmsion stages 
and their shape may or may not be quite similar. The presence of pro- 
chromosomes in resting nuelei has since been reported by many investi- 
gators. IMiyake (1905) for Galtonia candicans, Yamanouchi (1906) for 
Pohjsiphonia violacea, and Rosenberg (1907) for Hieracium Auricula and 
H. venosum. Laibach (1907) repeated Rosenberg’s studies on Capsella 
and verified the observations regarding prochromosonies; he also found 
that prochromosonies are present in a number of other Cruciferae. Davis 
finds prochromosonies in Oenothera grandiflora (1909) and in Oenothera 
biennis (1910). Lundegard (1909) adds to the above list of plants pos- 
sessing prochromosonies the species Calendtila officinalis, Achillea Mille- 
folium, Anthemis tinctoria and Matricaria Chamomilla. In his paper of 
1909 OvERTON gives a full review of the literature bearing on the tlieory 
of the individuality of the chromosomes. Later in the same year Rosen- 
berg (1909 b) reported the presence of prochromosonies in forty species 
of plants, and many still niore recent investigators have made similar 
