i?6 PROTOPLASM 



depended on coarser vacuolisation. Since both have a very 

 similar appearance, it is only possible to arrive at a true 

 decision on this point by a knowledge of their actual 

 dimensions, since we found throughout that the meshes of 

 the true protoplasmic structures scarcely exceed 1 p in 

 width. I am, therefore, obliged to consider the reticulum, 

 for example, drawn by Sedgwick (1886) in the egg of 

 Peripatus capensis as a coarser one which does not cor- 

 respond to the true structure of protoplasm, since the 

 width of the meshes is frequently drawn very coarse, and 

 even in the finest parts does not sink below 2 /*. I believe, 

 therefore, that in this as in many similar cases the trabeculse 

 of the so-called reticulum would themselves display the finer 

 protoplasmic structure. With regard to the general concep- 

 tion of the protoplasmic network Sedgwick approaches most 

 closely to Heitzmann and Frommann. 



As for Protozoa, Schuberg (1886) for Hursaria, etc., 

 Btitschli and Schewiakoff (1887 and 1889) for numerous 

 Ciliata, and Fabre-Domergue (1887) for the same order, 

 have in recent times been more especially deserving of 

 notice. With regard to the views of Kunstler (1882 and 

 1889), who followed out carefully the reticular structure 

 in the Flagellata, they must be gone into more closely 

 farther on. In histology, moreover, so many statements lie 

 scattered about in various works, that it does not seem 

 advisable to bring them together in full. Only Nansen's 

 work (1887) upon the reticular structure of ganglion 

 cells, which has already been discussed above (p. 147), 

 may here be referred to again. 



