190 
Proceedings of Royal Society of Edinburgh. [sess. 
cells (Q type). The terminals of the secondary coil were carried to 
two strips of platinum foil immersed in two insulated vessels (glass 
beakers or shallow vulcanite troughs) containing a *75 per cent, 
solution of common salt or sulphuric acid (1 : 10 of water). I then 
found that when the phonograph was set in action, and when the 
fingers were immersed in the vessels, an electric thrill was felt in 
the fingers which corresponded to the rhythm, time, and intensity 
of the tune played by the phonograph. By carefully graduating 
the strength of the induction shocks, each note and chord of the 
music can be distinctly felt. 
The experiment at once suggested a number of very interesting 
questions. Each variation in resistance in the microphone-trans- 
mitter produced by the varying pressures caused by the waves of 
sound was followed by a corresponding variation in the strength 
of the stimulus from the secondary coil, and the sensory nerves of 
the skin were capable of appreciating all these variations. The 
effects are most striking when the strength of the stimulation is 
such as not to be sufficient to excite muscular twitchings. Only a 
“ thrill ” should be felt. 
In the first place, what structures in the skin are stimulated by 
such electrical thrills? In the skin we have, richly distributed, 
numerous fine sensory nerve filaments. Whether these all termi- 
nate in end organs or not is a question that cannot at present be 
decisively answered, but the evidence rather favours the view that 
they do not all terminate in end organs. Sensations of touch and 
of temperature have been experienced and referred to small areas 
of skin which have been excised from his own body by the ardent 
experimentalist, and in which no end organs have been found 
by the aid of the microscope. To the skin we refer at least 
two well defined sensations, touch (which is essentially a sense 
of pressure) and temperature. Touch is believed to be connected 
with various kinds of touch corpuscles, but no end organ has yet 
been discovered for the sense of temperature. Further, in a given 
area of skin (say of the fingers) points may be found connected 
with touch, that is to say, tactile sensations are experienced when 
pressure is made on these points, while no sensation of touch 
follows pressure on a point a millimetre or two to one side of the 
tactile spot. In the same area there may also be detected what are 
