1 66 PROTOPLASM 



meshes was about 0*002 mm. after treatment with concen- 

 trated caustic potash, in which the network swells up, he 

 very likely had the true protoplasmic structure before 

 him. He found the epithelial cells of the efferent ducts to 

 be of a longitudinally fibrillar structure. It seemed to him 

 certain in the case of this object that the granulation of the 

 protoplasm could be referred to the reticular structure. In 

 1875 he extended his investigations more especially to the 

 liver cells of the Vertebrata, and saw in them a net-like frame- 

 work, which frequently became more compact round the 

 nucleus. As before, he found that the structure could be made 

 out even in the fresh condition, and only became more dis- 

 tinct under the action of reagents. In fact, he thought he had 

 observed slow movements in the threads by warming the 

 fresh liver cells on the slide. 



I think it would lead us too far if we tried to follow 

 out step by step the gradually increasing confirmations of 

 the reticular structure of protoplasm. In the following 

 lines, therefore, I will proceed more cursorily, and only lay 

 especial stress upon the more important and extended 

 bservations. 



In 1876 Schwalbe became an adherent of the theory of 

 reticular structure from his own observations on the colour- 

 less blood corpuscles of the crayfish, Triton, and various 

 ganglion cells. He also traced these structural relations in 

 objects as fresh as possible, and arrived at the important 

 opinion, which was enunciated here probably for the first 

 time, that the structural relations of the nerve cells 

 observed by M. Schultze and his predecessors depend on 

 regular arrangement of the trabeculse of the network. 

 " From all this it is obvious that isolated fibrillae are not 

 to be assumed in ganglion cells," was Schwalbe's conclusion 

 from his experiences. It is further of interest to note that 

 he considered net-like connections of the fibrillae of the 

 axis-cylinder as quite possible. 



In the same year Trinchese also described the net-like 

 structure of the protoplasm of various cells on the occasion 

 of the anatomical investigation of an opisthobranch (Cali- 

 phylla\ and of the connective tissue corpuscles of the frog 



