PROTOZOAN NUCLEI. 387 



the thinnest of sections, no such fibrils could be made out, al- 

 though an occasional microsome between the chromatin granules 

 aroused the suspicion that the latter are laid down on the cyto- 

 plasmic reticulum, in w^hich case the inter-chromatin cytoplas- 

 mic net might be called linin in view^ of the connection which 

 has been established between cytoplasmic and nuclear networks 

 in the Metazoa. 



In Euglcua the central granule apparently exerts an attractive 

 force during division. The chromatin granules aggregated in 

 the form of small rods — primitive chromosomes — are arranged 

 about it radially. The entire nucleus is surrounded by a deli- 

 cate though distinct membrane. 



Although the structure of the nucleus of Euglcua and its be- 

 havior during cell division have been carefully described by 

 Keuten, the differences between the chromatin and the central 

 body do not seem to have been sufficiently brought out. A 

 carmine stain, for example, is not sufficient to distinguish chro- 

 matin from plasmosomes and from the results shown by the 

 iron-hsematoxylin stain the central body w^ould appear to be 

 chromatin. A very delicate differential result is obtained by the 

 use of the Biondi-Ehrlich mixture of methyl green and acid 

 fuchsine (Auerbach's formula). After this stain the central 

 body is distinctly red and show's out in marked contrast to the 

 green of the surrounding chromatin. From this reaction it fol- 

 low^s that the chemical composition of the central body is differ- 

 ent from that of chromatin, a result w^hich brings this body 

 even more closely in line with the attraction sphere of the 

 higher forms. 



At this point Schaudinn's observations on Paramceba Eil- 

 Jiardi are interesting and important. Parainceba is a rhizopod 

 with flagellate swarm-spores. The spores resemble Cliilomonas 

 in general appearance, but a peculiar Nebciikorpcr is found in 

 the former which is lacking in the latter. This body is outside 

 the nucleus which, although it seems to have no nuclear mem- 

 brane, is nevertheless distinctly marked off from the rest of the 

 cytoplasm. During cell-activity the Nebenkorper assumes a 

 dumb-bell shape and, when the ends are well separated but still 



