PHYSIOLOGY OF THE NUCLEOLI 



65 



The contents of the nucleolus seem always less susceptible to the 

 basic stain than is the chromatin. While in the nucleus, however, the 

 nucleolar contents show a more basic reaction than the cytoplasm and 

 this tendency remains for some time after it has left the nucleus. But 

 in most cases the extruded nucleolus takes less of the basic and more 

 of the acid stain, untU it is quite as deeply or even more deeply colored 

 by it than is the surrounding cj-toplasm. 



Studying the phenomenon of the migration of the nucleoli 

 in the silk-gland cells of lepidopterous larvae, Maziarski paid no 

 special attention as we might desire, to this sort of changes. 



In order to throw some additional light upon this phase of the 

 subject, I stained the secretions of the silk-glands obtained 

 from the larvae of Neuronia postica and Pieris rapae, with dif- 

 ferent combinations of the stains. From this I got results simi- 

 lar in the main to those obtained by Walker and others in the 

 case of various other cells. 



Thus w^e see that: 



(1) The nucleoli within the nucleus are stained more or less 

 energetically by the acid as well as certain of the basic stains, 

 while 



(2) The migrated nucleoli always stain with acid stains 

 but they have no or very little affinity, if any, for the basic 

 stains. 



In the field of the cellular chemistry, it has been ah*eady 

 made known by Miescher, Kossel, Altmann, Hoppe-Seyler, etc., 

 that the ' nucleins' form a series leading downward from the pure 



