TRANSACTIONS OF SECTION 1. 651 
were conducted on well-marked pigment-spots of the species /?ana pipiens, and 
on higher reflexes, such as the turnover, compensatory, swimming, and equili- 
brium. The spots situated on the head are innervated by cranial, and those on 
the trunk and legs by spinal nerves. The spots chosen were among those that 
were found to exhibit a certain constancy for long periods in their reaction time 
to a definite stimulus. The stimulus that proved most satisfactory, causing little 
fatigue or injury to the peripheral nerve-endings, was an 8 per cent. pure acetic 
acid applied with a 3-millimetre square neutral filter-paper. The interval that 
elapsed from the moment the paper was placed until an attempt was made to 
remove it was taken as the reflex time. ‘To prevent injury to the spot it was 
immediately swabbed after each test with fresh water. A control reflex time 
was secured at different intervals from the corresponding spot on the opposite 
side of the body. 
Fixed doses of pure alcohol varying from 10 to 95 per cent. were tested and 
injected into a dorsal lymph sac, after the mean reflex time of a normal frog 
was ascertained. ‘The doses of alcohol varied from 0°05 c.c. of 15 per cent. to 
1 c.c. of 95 per cent., and the reaction time after these and equal amounts of 
Ringer solution were injected was recorded. It was seen that alcohol in such 
small doses as produced no apparent effect whatever upon the frog have a 
decided influence upon the reflex centres of some of the cutaneous sense-organs— 
at least in so far that their irritability is lowered, their reaction time slowed, 
and that when they are once affected by alcohol they do not return to normal 
reflex time again for some hours, often six to twenty-four hours, depending upon 
the condition of the frogs and their susceptibility to alcohol. From a long series 
of experiments it was seen that doses less than 0°05 c.c. of 15 per cent. alcohol 
per 10 grams frog had no more effect than an equal dose of Ringer solution. 
Beginning with 0°1 c.c. of 15 per cent., the doses have a depressing effect upon 
the reflex actions within ten minutes after injecting the alcohol, which effect lasts 
from one to one and a half hour, though the frog may appear restless. But the 
higher reflexes, such as the turnover, swimming, equilibrium, and compensatory, 
are not lost until doses of 0°3 c.c. of 30 per cent. are injected. Then the frog 
becomes sluggish, loses its muscle tone, and all spots lose their irritability, 
and the frog is generally depressed in its action. The depressing effect begins 
within ten minutes after injecting the alcohol, and may last two hours. With 
doses of 0°6 c.c. of 50 per cent. the higher reflexes may be normal again in two 
hours, but the sensory cutaneous areas are not normal again until the following 
day, and with this dose tetanic convulsions may appear. Doses of 1 c.c. of 
95 per cent. proved toxic. 
We see, therefore, that when the sensory spots fail to respond to the stimulus 
they do so immediately after injecting the alcohol. The depression increases, 
and is of longer duration with increase of dose. The reflex action of the sensory 
spots is lost before those of the turnover, swimming, compensatory, and equili- 
brium, and remain absent for longer periods. ‘Therefore, even small quantities 
of alcohol exert a depressing chemical action and never a stimulating increase in 
reflex time upon certain parts of the nervous system. These effects may indirectly 
affect the muscle tone, vaso-motor and cutaneous thermal reflex actions more or 
less extensively, depending upon the conditions of the susceptible nervous centres 
In considering equivalent doses for man, it is found that, for instance, a dose 
of 0'1 c.c. of 15 per cent. alcohol, which caused an immediate depression of the 
reflex time in the cutaneous sensory endings which lasted for about one hour, 
is equivalent to one pint of sherry or orange or port wine, or 113 pint of claret, 
or two pints of strong beer for a man of average weight. 
Charts and tables showing the position of the spots, a sample copy of the 
record of observations, and the tabulation of the reflex time of some of the 
sensory spots accompanied the paper. 
6. Nervous Induction in the Paths of the Pressure Sense. 
By Max von FRey. 
If two sensitive points of the skin, so-called pressure spots, are irritated 
simultaneously, the subject may have the impression of a double stimulus or of a 
single one. In the former case three other effects can be observed, viz., a 
