FRAMEWORK PRESENT IN UFE 205 



sap, or at times also form the lining of the cell wall. 

 The real intimate structure of protoplasm, on the contrary, 

 he has not observed, for which reason it becomes explicable 

 how he arrived at the idea that the filamentous proto- 

 plasmic structures gradually passed into the trabecuLe of 

 the protoplasm which usually traverse the cell sap of the 

 vegetable cell. A cursory study of the protoplasmic struc- 

 tures described in such numbers in animal cells would 

 necessarily have taught him that there are filamentous 

 structures which pervade the entire protoplasm, and which, 

 therefore, in no way permit of the interpretation attempted 

 by Schwarz. 



I think, however, that in the face of the numerous proofs 

 brought forward both in this and earlier works that not only 

 filamentous, but also reticular substances are frequently to 

 be observed in living protoplasm, the interpretation of them 

 as products of coagulation or precipitation requires no 

 further refutation. It has already been shown above that 

 the fibrillar structure of protoplasm always proves, when 

 accurately studied, to be a modification of the reticular 

 structure ; therefore, as I have already explained earlier, 

 the existence of the so-called reticular structure can be 

 inferred with a high degree of probability, if not with 

 certainty, from the demonstration of fibrillar structures in 

 living protoplasm. 



In opposition to the attempts to set aside the structures 

 as artificial products, it would seem worth while to give a 

 brief review of former observations which have demonstrated 

 structures in living protoplasm. Of course these statements 

 are not all of equal value, since occasionally without doubt 

 deceptive appearances or post-mortem alterations of the 

 protoplasm may have been seen such as may occur quite 

 easily, especially in the case of the cells of higher organisms 

 detached from their natural environment. 



That the structures of ganglion cells can be recognised 

 even in the freshest possible condition, has been confirmed 

 by the majority of observers since the time of M. Sclmlt/r 

 (1863), namely, by Schwalbe (1876), Arnold (1879), Dietl 

 (1878, for Helix), Freud (1882), Leydig (1883), and 



