28 CHARLES F. W. MC CLURE, 



die völlige Integrität des Kernleibes und seiner Membran bürgen mir 

 für eine normale Erscheinung." 



The writer has never found the slightest trace of a nuclear process 

 in the freshly isolated nerve cells of any Invertebrates, but can sub- 

 stantiate what RoHDE, in sections, has recently figured for such (38, 

 fig. 5 a, tab. 9). 



Rohde's figures show extensions (Ausläufer) of the nuclear chro- 

 matin into the cell substance. These extensions, he calls nuclear 

 processes (Kernfortsätze), and, as a rule, finds that they ran towards 

 the pole of the cell from which the axis-cylinder process is given off. 

 One feature of Rohde's nuclear process, which differs materially from 

 that figured by Schultze, is that in his case the nuclear membrane 

 is not continued along the sides of the nuclear process; a circum- 

 stance upon which Schultze lays a great stress. In fact, Rohde 

 says that in the larger cells the nuclear membrane is, as a rule, 

 absent, so that the nuclear and cell substances come into direct contact 

 with each other (38, fig. la, tab. 9). I have also noticed, in certain 

 of the larger cells of Helix and Arion, a somewhat similar condition. 



It is most certain, however, that these two processes (of Rohde 

 and Schultze) are not homologous structures, either from an ana- 

 tomical or a topographical standpoint. So far as can be seen by the 

 writer, only two interpretations can be put upon the structure de- 

 scribed by Rohde; either it is an artefact, that is, it represents an 

 instance in which the nuclear substance has been forced into the 

 "Spongioplasm", at a point of least resistance, by the general shrinkage 

 of the ganglion during the fixing process, or, if not an artefact, a 

 closer and somewhat different relationship exists between the nuclear 

 contents and the cell substance than has hitherto been observed in 

 nerve cells. In either case, Rohde's process cannot be a nuclear 

 process in the generally accepted sense of the word. 



With the exception of the "nuclear extensions" figured by Rohde, 

 the writer has never seen in sections any structures which might 

 seriously be taken for nuclear processes. 



Fig. 9 is taken from a section of an Helix ganglion which had 

 been fixed in sublimate and cleared in xylol, and in which signs of 

 shrinkage were visible. The evagination in the form of a nuclear 

 process is unquestionably an artefact, and represents one of many 

 abnormal conditions which may occur in material improperly treated. 

 If at the point where this evagination has taken place, the nuclear 

 membrane had been broken or even absent, as it may be according to 



