Evening star., 1907-08-23
STUDYING FISHES MEMORY
INVESTIGATIONS INTO THE BE-
GINNINGs OF THE MIND.
Researches at Carnegie Institution
Laboratory on Loggerhead Key.
Experiments on Gray Snapper.

From the Independent.
The Carnegie Institution laboratory at
the Tortugas consists of seven buildings
upon Loggerhead Rey, and Is designed to
afford the best possible facilities for the
study Of the life of the gulf stream and the
coral reefs. The laboratory is provided
with seagoing yacht and three good
launches for visiting the neighboring reefs
and for cruises over the gulf stream. The
yacht is sixty feet long and can remain at
sea for weeks at a time being provided with
powerful engine and sails.
Researches have been conducted during
the last two summers, too short a time
since the opening of the laboratory to per-
NIT me to speak personally of the invest-
gators or in detail of their results, especial
ly as many of the researches are of elab-
crate nature ard are not yet completed for
publication. The following brief statement
will, however, give fair idea of some of
the best-estabiished results achieved by
investigators working at the laboratory.
Fishes of Florida Reefs.
One investigator studied the habits of the
reef fishes and found that the most abun-
dant predatory fish of the Tortugas reefs
was the gray snapper, which commonly
feeds upon little sivery sardine. If some
Of these sardines be dyed bright red and
then thrown into the sea, together with
some normal Silvery sardines. the Silvery
ones are at first eaten more readily than the
red, but the gray snappers soon learn that
prlght red sardlneS are good to eat, and
will then devOur them as eagerly as if they
We're normal in color. The investigator then
dyed some sardnes bright blue and threw
them in. together with red and silvery
ones. AT first the blue were relatively avoid
ed. but soon the gray snappers learned
that they, too, were palatable. Small por-
tons of jellyfishes were now attached to
the blue sardines, and the gray snappers
seized them greedily, but were stung by the
pieces of jellyfsh. In a few minutes they
learned to avoid the blue, but still ate red
and silvery sardines. The next day, how
ever, the gray snappers had forgotten this
experience, and the patient investigator
was obliged to teach them anew.
another investigator demonstrated that
even such lowly creatures as sea anemones
and corals pursue the method Of trial and
nize things injurious and avoid them
Moreover, they at first avoid each sort of
injurious stimulus in fixed and constant
way, but if this fails they adopt new meth
ods
Memory of Caterpillars.
The associative memory of caterpillars
may endure about half minute but they
cannot retain the memory of an experience
for so long a time as a minute and a half.
trivial to the lay reader, but their import
increases when we consider that in these
Simple forms we are dealing with the be-
ginnings of mind.
One of our most distinguished biologists
working at the Tortugas found that the
substance of the eggs of jellyfSh is differ
entiated into three concentric layers, one
of which forms the outer skin, one the mus
cular or supporting mechanism and one the
digestive system. Previously he had dis
nina 1C
were organized in the same manner. He
thus strikingly demonstrated the intimacy
of relationship which pertains between the
highest and the lowest of animals The diff
ference between a jellyfish and vertebrate
is mainly one of degree, not of kind.
Another investigator has carried out a
very carefully planned series of observa-
tions upon regeneration which show that
the animal with the greater number Of re-
moved parts regenerates each and every
part more rapidly than the animal with the
lesser number of removed parts.
Parasites and Protozoa.
Studies upon mullusks, tunicates. fishes,
fish parasites are protozoa are being pur-
sued, and series of elaborate observations
will soon be published upon the reactions
Of crabs and starfshes. and upon the de-
velopment of jellyfishes discovered at Tor
tugas.
One student finds that the pulsation of
mails is strongly stimulated by the sodium
potassium and calcium chorides of the sea
water, or of the fluids permeatng the
heart; but magnesium inhibts this stimu-
lus, thus causing the pulsating organ to be
merely upon the threshold of stimulation
and allowing slight internal stimuli to pro-
duce rhythmical contractions Organs can
pulsate only when a stimulus is counter
balanced by an inhibitor. thus allowing one
or the other to alternately control the reac-
ton.
A method of reviving pulsaton in para
lyZed jellyfshes was also discovered, and it
was found that the pulsation stimulus is
transmitted by the skin or by diffuse
subcutaneous nervous network, not directly
by the muscles themselves.
But the Tortugas laboratory is only the
youngest member of series of laboratories
along our Atlantic seaboard. to say nothing
of the vigorous young growth upon our Pa
citic coast. All strive in a common cause
to advance the confines of human knowl-
edge What is lfe?" is the burning ques-
tion of biology today, and although this
deepest of natures secrets may never be
revealed to us, yet light is being thrown
upon it year by year, and we hope for we
know not what.