i6o PROTOPLASM 



and 1871), the doctrine of the fibrillar structure of proto- 

 plasm of nerve cells was confirmed and further developed. 



Frommann, who, as far back as 1864 and 1865, occupied 

 himself with the careful investigation of the fibrous struc- 

 ture of ganglion cells, and chiefly sought to show that the 

 fibres of the protoplasm arise from the nucleus and nucle- 

 olus, came in 1867 to the conviction that the fibrous 

 structures were not only a specific peculiarity of nerve cells, 

 but probably formed a universal peculiarity of protoplasm. 

 Since his work of 1 8 6 7 is unfortunately not accessible to me, 

 my judgment is limited to what he himself (1884) and others 

 have reported on the subject. As has been said, Frommann 

 had, on the one hand, observed similar fibrous structures, 

 taking their origin from the nucleus, in numerous other 

 kinds of cells also, but he further occasionally remarked 

 filamentous connections between the granules of the proto- 

 plasm, and similar ones between those of the nucleus. 

 Supported by these observations, the question seemed to him 

 even then worthy of consideration, whether a network 

 might not unite the granules of the protoplasm, and whether 

 the latter might not themselves be merely the nodal points 

 of such a network. Although, therefore, Frommann in 1867 

 had not, properly speaking, by any means observed the 

 reticular structure of protoplasm, yet the real merit is 

 due to him of having pointed out the possibility of such a 

 structure, and of having at the same time recognised the 

 structural relations already discovered in ganglion cells, as 

 being probably a universal peculiarity of protoplasm. 



Simultaneously and independently J. Arnold (1865 and 

 1867) had also observed fibres united into a network in the 

 ganglion cells both of the sympathetic and of the spinal 

 column, and had seen fibres running out on various sides from 

 the minute granules of the protoplasm. He also laid stress 

 on the connection of these fibres with the nuclear corpuscles, 

 or rather with the fibres of the nucleus. 



Fibrous or striated structures had, however, already been 

 seen at quite an early period in certain epithelial cells. 

 Friedrich in 1859 described the striated structure of the 

 ciliated cells of the EpendyTna ventriculorum of man. In 



