174 PROTOPLASM 



were supposed to be of two kinds, the one " passive," i.e. 

 such as are produced by vacuolisation, the other " active," 

 the result of the granules becoming grouped into filaments 

 or nets. It will be sufficient here to have mentioned this 

 view, since in the sequel we must return to it in more 

 detail. 



Without taking special notice of the occasional descriptions 

 given by Affanasiew and Langley of reticular structures in 

 liver cells, we proceed at once to the extended investigations 

 which Carnoy in 1884, 1885, and 1886 published upon 

 the subject of protoplasm. Since with regard to the struc- 

 ture his standpoint is entirely that which was developed by 

 Heitzmann, and which has been reverted to essentially in 

 the views of Schmitz, Leydig, and van Beneden, it does not 

 require to be set forth in detail here. Living protoplasm 

 was but little investigated by Carnoy ; hence he nowhere 

 discusses the very important question how the occurrence 

 of apparently quite homogeneous protoplasm is to be ex- 

 plained on the general hypothesis of the reticular structure. 



Carnoy also recognises the fact of fibrous and radiate 

 structures having originated by modification of a perfectly 

 reticular structure. The framework is definitely regarded 

 by him as solid, or at least very viscid, and contractile ; 

 the intervening matrix, on the other hand, is supposed 

 to be " hyaline and viscous." Nevertheless I certainly 

 believe that Carnoy also has partly mistaken coarsely 

 vacuolar structures for the real fine protoplasmic structure ; 

 this is quite evident from the fact that he identifies 

 the network of coarse trabeculse in the protoplasm of 

 Noctiluca with the. finer protoplasmic framework, and 

 regards the cell sap of this Protozoon as equivalent to the 

 enchylema or intervening matrix of protoplasm. Moreover, 

 I also infer this from the fact that Carnoy frequently 

 represents the enchylema finely granulated, which leads one 

 to conclude that at times he only saw the coarser network, 

 and regarded the finer one as granulations. In opposition 

 to Leydig, he incorrectly makes out the granular contents of 

 the protoplasm to be located always in the enchylema, 

 which is supposed to frequently contain even the coarser 



