CHAPTER VIII 
KEIMBAHN-DETERMINANTS AND THEIR SIG- 
NIFICANCE 
Iv is customary to be suspicious of any peculiar 
bodies revealed to us in fixed and stained material 
under high magnification. There can be no doubt, 
however, that most, if not all, of the cytoplasmic 
inclusions mentioned in the preceding chapters are 
realities and not artifacts. Some of them have been 
seen in the living eggs; most of them have been de- 
scribed by several investigators; they occur after 
being fixed and stained in many different solutions ; 
and their presence is perfectly constant. The 
genesis, localization, and fate of these bodies are 
difficult to determine, and their significance is prob- 
lematical ; but the writer has attempted in the follow- 
ing pages to draw at least tentative conclusions from 
the evidence available and to indicate what still 
needs to be done. 
A. Tue GENESIS OF THE KEIMBAHN-DETERMINANTS 
The writers who have discussed the origin of the 
keimbahn-determinants have derived them from 
many different sources. In afew cases they are known 
to be nuclear in origin, consisting of nucleolar or chro- 
matic materials; they are considered differentiated 
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