NERVE CUTTING IN AMIURUS 391 
end. Moreover, in a few individuals, he found an abortive 
attempt at head regeneration of such a nature as to hint most 
strongly that there was a reciprocal formative relationship 
between these head structures and regenerating nerve cord. 
There are, therefore, two classes of regenerative phenomena: in 
one the presence of the nerve is necessary for complete regen- 
eration, in the other it is not. The experiments on Amiurus 
point most definitely to an intimate relationship between nerve 
and regeneration. 
j SUMMARY 
1. Taste buds in Amiurus are composed of one kind of cell, 
the sense cells, ‘cover’ and ‘basal’ cells being absent. 
2. Intrageminal nerve fibers impregnated with silver by the 
ordinary methods appear to lie between the taste cells, not within 
them. 
3. Evidence is given to show that the small leucocytes and 
larger wandering pigment cells included within the buds are 
different stages of the same phagocytic cell. When this cell 
becomes filled with waste material it is extruded from the surface 
of the skin. ( 
4. Within eleven to thirteen days after cutting the branches 
of the seventh nerve leading to the different barbels, the taste 
buds on these barbels completely disappear. 
5. The first evidences of degeneration of the nerve occur on 
the eighth day after operation, and become complete about the 
thirteenth day. 
6. The taste buds do not eaerentiat into epithelial cells, 
but degenerate, and are phagocytized by wandering leucocytes. 
Their places are taken by indifferent epithelial cells. 
7. About the eighteenth day the nerve begins to regenerate 
at the base of the barbel and the taste buds again appear in ves 
same area. 
8. By the end of forty days physiological tests show complete 
restoration of function to the barbel, and sections show complete 
restoration of all structures in the barbel, i.e., nerve and taste 
buds. 
