iv GEXEKAL PHYSIOLOGY OF NERVOUS SYSTEM 189 



of inter-neuronal anastomosis, that the nature of the connection 

 between the elements of the system may have developed in two 

 opposite directions in the course of phylogenetic evolution. He 

 accepts the theory of Apathy for invertebrates, but maintains that 

 of Eamon y Cajal for vertebrates, so long as the continuity of the 

 fibrils which compose the central and peripheral elementary net- 

 work is not positively demonstrated. 



The most emphatic and certainly one of the most reliable 

 supporters of the theory of Apathy and Bethe, for both in- 



Fio. 124. Two cells from ventral horn of human spinal cord. (Nissl's method.) The chromatic 

 substance is collected into small masses, which give a speckled appearance to the cytoplasm. 

 Each cell, besides the nucleus and nucleolus, contains a distinct mass of stainable granules. 



vertebrates and vertebrates, is Nissl, although his own work does 

 not refer specially to the fibrillary structure of the nervous 

 system. In 1893 he discovered the existence in many ganglion 

 cells of peculiar granules which stain with basic aniline dyes, 

 particularly with methylene blue and toluidine blue. These 

 which are now generally referred to as Nissl's granules or chromato- 

 phile granules are present in small masses throughout the body 

 of the cell and in the larger dendrites (Fig. 124). 



Nissl holds that since the fibrillary nature of the achromatic 

 part of the ganglion cell has been established, the theory of the 

 nerve unit (neurone) is no longer tenable. He concludes, on the 

 strength of the researches of Apathy, Bethe, and Held, which 



