iv GENERAL PHYSIOLOGY OF NERVOUS SYSTEM 185 



Levi, Lugaro's collaborator, obtained similar results from the 

 ganglion cells of frogs during hibernation, in which state the 

 chromatic subtance is very scanty, so that the achromatic fibrillary 

 part is more conspicuous. 



The existence of fibrils in the nerve-cell and its processes may 

 be regarded as fully established by Apathy's work on the nervous 

 system of the Anellidae (1897). He demonstrated definite fibrils 

 by a special method of staining the ganglion cells with gold 

 chloride. As shown by Fig. 121, these fibrils penetrate from the 

 dendrites into the cell body, where they form a wide -meshed 

 network, and then collect into a single bundle, and leave by the 

 axis-cylinder. The fibrillary network (Apathy) assumes different 



Fio. 121. Ganglion cell of ventral cord of Lumbricus, showing an endocellular fibrillary network, 

 which is continuous with the afferent fibrils of the dendrites, and with one larger, efferent 

 fibre of the axon. (Apathy.) 



forms according to the nature of the ganglion cells. The small 

 fibres brought out by the gold stain are shown to be bundles of 

 very delicate elementary fibrils, which escape observation owing 

 to their size and the inadequacy of the staining methods. These 

 are the conducting elements proper of the nervous system. 



Any one who has studied the preparations obtained with 

 Apathy's method must admit that they exhibit astonishingly 

 clear details of structure, which may be of fundamental import- 

 ance to physiology. At the same time it must be remembered 

 that Apathy's positive results relate solely to the nerve-cells of 

 the lower animals (Hirudo and Lumbricus}, and that in spite 

 of prolonged experiments, nothing exactly corresponding has so 

 far been obtained in vertebrates. 



Bethe, in a series of interesting observations (1897-1890), 

 endeavoured by other special methods of elective staining of the 



