434 TRANSACTIONS OF THE CANADIAN INSTITUTE. [VoL. VI. 
these bodies can be easily followed. I find it is not the accessory 
nucleoli that retain the stain but the ordinary nucleoli themselves. In 
all places examined by Rohde (spinal and sympathetic ganglia) it is 
well known that several nucleoli are found, as can be easily seen by 
staining with toluidin blue. In the cells of the cord where one nucleolus 
is the rule, it is this nucleolus which retains the iron-alum haematoxylin 
stain, and not the neighbouring oxyphile substance. 
If these nucleoli which retain the hematoxylin stain are outside the 
nuclear membrane they are artificially brought there. One can some- 
times find, as v. Lenhossek has pointed out, the nucleolus pulled out of 
the spinal ganglion cell. He believes this occurs because the nucleolus 
is loosely attached to the linin thread, or because the nucleolus is very 
hard under certain conditions. I have never seen a nucleolus outside 
the nuclear membrane in the cells of the cord, and in ganglia that have 
been fixed in sublimate this appearance is far more common than it is in 
material that has been fixed in alcohol. The fact, (and I have carefully 
examined my preparations to see that it is a fact), that where more than 
one cell have their nucleoli displaced in the same section the direction 
of the displacement of the nucleoli is always the same, shows that 
these have been displaced in cutting. One can make the appearance 
of migrating nucleoli quite common, if one cuts sections, I or 2 » 
thick, of ganglia fixed in sublimate, but all the apparent migration is in 
the same direction. If, however, thicker sections are cut, or if material 
that has been fixed in alcohol is used, the appearance may be said to be 
non-existent. 
Holmgren® also believes in the migration of formed masses of 
the nuclear chromatin to the cytoplasm. In the cells of the spinal 
ganglia of Lophzus he has described the migration of the chromatin out 
of the nucleus to form the Nissl granules, the migration of accessory 
nucleoli, and the passage of the Nissl granules back into the nucleus 
These changes are brought about through the agency of the micro-centre 
with its radiating threads, and are supposed to be different stages in the 
activity of the cells. Some of the cells observed so differed from the 
usual condition that they could only be considered as dying, and yet it 
is from cells in the same ganglia that these changes are described. 
Holmgren tries to justify his position by a study of the cells of Acan- 
thias, Gadus, Raja, and Rana, in which similar conditions were observed. 
In the spinal ganglion cells of Raza I have never observed such con- 
ditions, except in cases which are manifestly artifacts made in cutting, as 
88 Emil Holmgren, ‘‘ Zur Kenntniss der Spinalganglienzellen von Lophius piscatorius Lin.” Anat, 
Hefte, XXXVIII, p. 71,1899. 
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