C. ESTABLE 



317 



bodies (soniato-soiiiatic synapses) (Fig. 12) and between axons [cixo-axoiiic 

 synapses). The latter kind includes three different types: {a) parallel 

 contacts; (/>) cross contacts; (c) axon endings on a non-terminal part of 

 another axonic fibre. In the ganglia of Invertebrates, only axodendritic, 

 axo-axonic and dendro-dendritic synapses exist. 



Fig. 8 

 IDcnclro-dendritic and dendro-soniatic contacts. Micrograph of the human dorsal spinal 

 cord (3 months old embryo); section perpendicular to the plane of symmetry. See dis- 

 position of dendrites in the interneuronal fascicles in which many dendro-somatic and 

 dendro-dendritic contacts take place. (Cajal's silver method.) 



Close dendro-dendritic, dendro-somatic, dendro-somato-dendritic and 

 somato-somatic contacts having been brought to light in all nervous 

 regions explored and, if at variance with the principle of polarization of 

 the nervous influx, might well explain many until now unexplained 

 physiological processes of the nervous system. Consequently, we hnd it 



