NOTES ON SPOROZOA — III. 
205 
above^ and that no proinitotic division of this body 
occursd 
Nature and S i g n i fi c a ii c e of the K a r y o s o ni e . 
I have laid stress upon this fact of the presence of an iutra- 
karyosomatic centi-osoine because of tlie important bearing it 
lias upon the question of the real nature and significance of 
the karyosome, and because it helps to explain satisfactorily 
the different behaviour of this body in different phases of the 
life-history. In the first place, it is necessary to clear the 
ground of Avhat I consider is a serious misconception of the 
karyosome, which is largely fostered by the school of Hart- 
mann, Niigler and others, and which appears to be based 
upon the fact that this organella frequently leads the way in 
nuclear division, and contains within itself a division-centre. 
Now, the primary and principal meaning of the term karyo- 
some is chromatin-nucleolus, i. e. a body consisting of a 
plastin basis impregnated with chromatin ; it might be con- 
sidered unnecessary at the present day to have to emphasise 
tliis essential character, but that this is not so is shown by 
Ueichenow’s reference to it as one “ auf den wir keinen 
grossen Wert legen diirfen ! ” This is the sense in which the 
word was first used, and on account of which it has been 
adopted by most authors (cf. Labbe (13), Minch in (19), 
Siedlecki (33 and 34), Wilson (38) and others). Schaudinn, in 
his celebrated memoir on the Coccidia of Lithobius also 
says: “ Jeden Falls unterscheidet sich das Karyosom der 
Coccidien von den echten Nucleolen der Metazoenzellen 
scharf durch seinen Chromatingehalt.” But in many recent 
papers by members of the school of thought i-eferred to above, 
a strong tendency is noticeable to assume that the possession 
of a centrosome and of the function of acting as a division- 
centre is to be definitely associated with the idea of a kaiwo- 
soine as a whole and to be implied in the meaning of the 
' See also the account given in Note lY of the imclear structure of 
fmucocy tozoon niul H:i 1 ter i d i u in, in hotli of whicli division-centre 
and centrodesinoso are clearly shown. 
