SCHMITZ—FROMMANN 169 



toplasm ; these are questions which still require the most 

 careful ohservation in order to obtain a final answer." At 

 the same time Arnold confirmed the existence of filamentous 

 structures in the cells of numerous tumours. 



On the botanical side Schmitz (1880) came forward to 

 support energetically the universal distribution of the re- 

 ticular structure of protoplasm. He observed it in material 

 preserved with concentrated picric acid. It can be af&rmed 

 with great certainty that Schmitz had not seen the true minute 

 structure of protoplasm, but only more coarsely vacuolated 

 structural appearances, just as Strassburger had done. For 

 instance, he describes the original protoplasm as being 

 in general finely punctated, and the reticular structure as 

 first arising in this. The frequently repeated remark that 

 the cell sap cavity arises by flowing together of meshes of 

 the protoplasmic network also expresses the same view. 

 Schmitz is, however, of the opinion that the punctation 

 of protoplasm which is not distinctly reticular is only the 

 optical expression of a very minute net-like structure, and 

 that, therefore, both the modifications of protoplasm pass 

 one into the other. On the other hand, he tries to refute 

 any interpretation of the structures observed as phenomena 

 of coagulation, or artificial products of any other kind. 



Frommann published, from the year 1879 onwards, a 

 series of communications on his further studies of proto- 

 plasmic structures, which it would take too much time to 

 even enumerate here. They extended to various cells of 

 the animal body, such as cartilage, ganglion ceUs, epidermic 

 cells, and blood corpuscles, as well as to various vegetable 

 cells. In 1884 he brought together the greater part of these 

 investigations, and set them forth with increased accu- 

 racy. We will, therefore, attempt to give a rather more 

 exact account of the opinion which Frommann has formed 

 upon the ground of his numerous studies, with the help of 

 his description of 1884. It must first be pointed out that 

 he found reticular structures everywhere in the protoplasm 

 investigated. The network or framework was not, however, 

 one connected together on all sides and at all points ; on the 

 contrary, isolated portions of it frequently occurred. As a 



