NERVE CUTTING IN AMIURUS BAIL 
In justification of this idea of dedifferentiation, Semi Meyer 
refers to the statement of Szymonovicz (95), that the tactile 
corpuscles of Merkel arise through differentiation of epithelial 
cells brought about by the entrance of the nerve fiber. There- 
fore, he contends, if the presence of the nerve determines the 
form and function of these cells, transforming an indifferent 
epithelial cell into a highly differentiated sense cell, why should 
not dedifferentiation take place when that influence is removed? 
This argument rests on analogy only, though there is evidence 
that taste buds are differentiated from epithelial cells through 
the advent of the appropriate nerve (Olmsted, ’20). 
In none of these experiments does there seem to have been 
any attempt to correlate changes in the taste buds with the 
degenerative processes in the nerve. According to Howell (20), 
degeneration of the nerve stump in the dog and most other 
mammals begins in a few days—four at the latest. In the dog 
it proceeds so rapidly that the process seems to be simultaneous 
throughout the whole peripheral stump. But in the frog and 
rabbit the degenerative changes begin at the wound and progress 
peripherally. 
The most extensive studies of nerve degeneration have been 
carried out by Howell and Huber (’92) and Mott and Halliburton 
(01). From the data of these investigators it will be seen that 
the first degenerative changes in the taste buds of dogs whose 
ninth nerves have been cut coincide in point of time with the 
initial degenerative changes in a severed nerve. 
METHODS 
Since the fish Amiurus possesses taste buds on its barbels 
and the nerves leading to them are easily accessible, this fish 
lends itself most readily to experiments which attempt to answer 
the questions raised by the work on mammals. It must be 
borne in mind that in this problem the conditions are somewhat 
different from those in mammals. We are dealing with a fish, 
a cold-blooded animal and a much lower form of vertebrate than 
a mammal. Howell (20, p. 125) states that in the frog—a 
