2o0 
J. STUART THOMSON. 
]\[y experiments to test the physiological value of the taste- 
buds consisted in bringing various forms of food into contact 
with, or into the proximity of the groove surrounding the 
vibratile fin. I find that it is of the utmost importance in 
these experiments that the rocklings should, firstly, have 
become thoroughly habituated to the artificial enviroment 
of an aquarium. The rocklings are so shy and easily dis- 
turbed tliat when brought in fi-om the shore they are for 
some time too excited to have any desire for food. 
The most successful experiments were made with a fish 
which had been many months in an aquarium, although with 
other rocklings which had been a, week in captive conditions, 
similar, though not such satisfactory, results were obtained. 
A further item to be considered in these experiments is the 
reckling’s hatred of light and of light-coloured surfaces. As 
the rockling is primarily a night-feeder, I conducted many 
of my experiments at night, and as showing their sensitive- 
ness to light, it may be remarked that it was found necessary 
to keep the candle-light in a more or less shaded position. 
In spite of these hindrances, however, the reflexes or responses 
obtained were definite and precise. 
Ill my earlier experiments I tried the effects of various 
extracts of beef. In these I directed a current of fluid beef 
extract by means of a pipette against the surface of the 
groove on which the taste-buds are situated. The result of 
this was a response on the part of the rockling accompanied 
by a swallowing of the liquid food. As a control experiment 
I directed a current of sea-water against the same parts, but 
was unable to detect any response. 
Subsequently I tried similar experiments with small pieces 
of liver, the muscles of crayfish and fish, etc., which were 
held near the taste-buds by means of a thin wire ; the result 
was that responses were obtained, but not so definite as 
might be desired. The clearest and most reliable reflexes 
or reactions were, however, obtained on using living lob- 
worms as the bait. Small, living lobworms or parts of these 
were gently let down through the water upon the skin of the 
