The Dawn of Reason; or, Mental Traits in the Lower Animals

e sense of touch,-from which all the other senses have been evo

; and, if our own senses were acute enough, it is more than probable that we wo

as the sense of touch. My own observations teach me that certain actinophryans,[5] minute, microscopic animalcules, can dif

were numerous Brachioni in the water) with one of its pseudopodia, which it would then retract, until the captured Brachionus was sa

irected to its prey by the movements of the latter, but f

nd some minute crystals of uric acid upon it. Whenever the actinophrys touched a starch grain with a pseudopod, the latter was at once

ich is exceedingly low in the scale of animal life, recog

stances, which, after a time, they get rid of by a process the reverse of that which they use in "swallowing." By the latter process they put themse

eader will pardon me if, while discussing this sense, I prove to be a bit discursive. The

h side of the head. From upright fishes, swimming, probably, close to the surface of the sea, they became dwellers on its bottom, and, in order to hide themselves more effectually from their enemies or their prey, they acquired the habit of swimming with one side next to the ground, and of partially or wholly burying themselves in the mud, always, however, with one side down. They thus became flat fishes, losing the coloring of their under surfaces, and their eyes migrating across their foreheads and taking

organs of sight have degenerated, and are now practically worthless as far as vision is concerned. All moles, however, can tell darkness from light, consequently, are not wholly blind-a certain amount of sight remains. This is due

ion of light, so that totally blind animals, animals with no rudimentary organs of vision whatever, and the inception of whose ancestors, themselves wholly blind, probably took place thousands of years ago, show by their actions that light is exceedingly unpleasant to them. Th

In point of fact, I think it can be demonstrated that light is directly fatal to these fishes; t

ever been able to discover any), thus showing that their appreciation of light is not derived through the agency of their eyes. An eyeless spider (An

y (he had never been in a brewery before), and asked him if it were light or dark. He answered that it was almost as light as day. I then conducted him into the dark beer vaults, and as soon as he passed the door he excl

ity (sense of touch) to such an extent that it has partially taken on the fu

erved by many of the true worms. I am inclined to believe that Semper would find primitive eyes of some form or other in the Cymothoe he mentions, if he were again to examine it. The insects, etc., which dwell in caves, and which have eyes, are new arrivals; they have not dwelt long enough in total darkness to have experienced the full effects of changed surroundings. They show, however, that they are beginning to feel such effects, for there is more or less diminution in the color-cells of the eyes and body coverings. My experiments on fish and frogs show, conclusively, that the color-producing function is directly due to light stimulation. The longer fish and frogs are kept in total darkness, the lower is the number of color-cells and the smaller is the amount of coloring-matter

e, and that it is to be found in a primitive form (ocelli) in animals of excee

hese early organs of sight are to be found in the medusa, or jelly-fish. This creature, with its bell-shaped body and pendent stem, bears a striking resemblance to an umbrella; noting this resemblance, naturalists have given the name manubrium, "handle," to the stem. Around the edge of the umbrella, and situated at regular intervals, are certain round, cell-like organs, which vary considerably in number. Some species have only eight, while others have sixty, eighty, and even (in ?quorea) as high as six hundred.[8] These so-called "marginal bodies" are the eyes of the jelly-fish. By many biologists these organs are considered to be ears; they contain within their capsules transparent bodies, which some scientists deem otoliths, or "hearing-stones." Experimentation and microscopical examinations, however, have taught me very recently to believe othe

ed over the dorsal surface of the creature's body, and are commonly situated just beneath the skin; they are, however, sometimes elevated on pear-shaped bulbs. The eyes of starfish are generally quite primitive in character, as

y gourmands and epicures, but bright spots around the edge of the mantle)-primitive eyes, it is t

re brought to a high degree of perfection. This worm is exceedingly transparent, so that when observing it, it is difficult to make out more than its large orange eyes and the violet segmental organs of each ring. It looks like an ani

separate from the parent worm and begin life as individuals. These in turn eventually become multiple worms and divide into individuals, and so on ad infinitum. The tail worm, or that section farthest from the head, is the oldest and is always the first to leave its comrades and take up a separate existence. The adverb always in the above sentence is, strictly speaking, not exactly accurate, for on one occasion I saw the separation occur at the second head from the tail, thus producing twins. The two sections came apart, however, in a very few seconds after their departure from the colony. I am inclined to believe th

ton or twine, at a distance of two feet. In my experiments I used a pole ten feet in length, from the tip of which a white or dark ball was suspended by a string. The ball was made to describe a pendulum-like movement to and fro in front of the snail on a level with the tips of its horns. Time and again I have seen a snail draw in its horns when it perceived the white ball, to it an unknown and terror-inspiring object. I have likewise seen it change its line of march, and proceed in another direction, in order to avoid the mysterious white stranger dancing athwart its pathway. Dark-colored objects are not so readily perceived; at least, snails do not give any evidence of having seen them until they are brought within a foot of the creatures under observation. A snail will generally see a black ball at twelve or fourteen inches; sometimes it will not perceive the ball, however, until it has been brought to with

rch of another home. When it had found it, it returned and assisted its sick comrade to go thither, evincing toward it, throughout the entire journey, the utmost tenderness and solicitude.[13] The health

The apex of this cone is prolonged into an exceedingly small tube, that enters a striped spindle-like body called the striated spindle; the entire structure is called a visual rod. Nerve-fibrils emanating from the optic nerve enter the striated spindle at its lower extremity, and in this way nervously energize the visual rod. There is a deposit of pigment about the visual rod which arrests all rays of light save those which strike the cornea parallel to the long axis of the crystalline cone. We see from this that the visual picture formed by a crayfish

ement of its food. This is undoubtedly true where the animal is surrounded by water that is muddy, or that is otherwise rendered opaque. T

t least, the sense of sight directed them. Again, I have enticed crayfish from clear streams by slowly dragging a baited hook in front of them. Moreover

til they have grown strong enough to enter life's struggle. At such times, the mother crayfish is quite brave, and will do battle with any foe. With her eyestal

When approaching a crayfish "town" for the purpose of making observations, I use the utmost caution; otherwise, eac

rue cosmopolite, however, and is as much at home on dry land as it is in the water. All seasons seem to be alike to it, just so the sun shines; for, during the hottest days of summer and the colde

bble of air caught beneath the wing-tips; or, as the late William Hamilton Gibson expresses it, "they carry a brilliant lantern that goes gleaming like a silver streak down into the depths, for a bubble of air is caught beneath their black wing-covers, and a diamond of pure sunlight accompanies their course down among the weeds until they once more ascend to the sur

Periophthalmus, a fish inhabiting the coasts of China, Ja

life, in an element which, according to the general nature of things, ought to be fatal to it. The laws of evolution have, however, eminently prepared it for its peculiar mode

ong certain lines has so developed its pectoral fins that the creat

all sides, hence its name, "periophthalmus," which is derived from the Greek words, περ?, around, and ?φ

and are not worthy of special mention, but its dorsal eyes, sometimes several dozen in number, are truly remarkable. These eyes, although they are very simple in structure, in type are the same as those of vertebrates, h

or so of little bladder-like cells in the skin of its back, thereby discharging a hailstorm of minute concretions in the face of its enemy. The fish

rrogance and pride of Polyphemus, and Arges, and Brontes, and Steropes, and all the rest of the single-eyed gentry who, in the days of myths and myth-makers, inhabited the "fair Sicilian Isle." The animal in question is a small lizard, called Calotis. Its well-developed third eye is situated in the top of its head, and can be easily seen through the modified and transparent scale which serves it as a cornea. Many other lacertilians have this third eye, though it is not so highly organized as it is in the species just mentioned. A tree li

accumulation of pigment-cells which serves to arrest light rays (in simple organisms such as rotifers) to

ind become higher and more involved. We see, in periopthalmus, a creature exceedingly well adapted by form, function, and intelligence to its manner of life. We must admi

ommonly, it is a hollow hair, which is connected by a minute nerve-filament with the sensorium. Sound vibrations set the hair to vibrating, which in turn conveys the vibrations to the ne

hear just as we hear. It is also highly probable that the so-called deaf animals can hear, just as we hear whe

stion of audition in the lower animals will, probably, never be definitely s

ugs (Hemiptera), they are located elsewhere. The habit that almost all insects have of retracting their antenn? when alarmed by noise, or otherwise, has done much to advance and strengthen the opinion that these appendages are the seat of insect ears; yet I am confident that in nine cases out of ten the antenn? are retracted through fear of injury to them, and not through any impression made on them by sound. The antenn? are the most exposed and least protected of any of the appendages or members of the insect body; hence their retraction by insects when alarmed is an instinctively protective action. They shelter them as much as possib

enters the tibia it becomes enlarged and divides into two channels; these two channels unite again lower down in the shaft of the tibia. The trache? of non-stridulating grylli are much smaller than those of sound-producing grasshoppers. The same may be said of the tibial air-tubes of the so-called dumb crickets. In grasshoppers and crickets the ear-d

which vibrates in unison with some particular number of sound vibrations. The organ of Siebold in the grasshopper's ear begins with vesicles, of which a few of the first are nearly equal in size; these vesicles then regularly diminish in size to the end of the series. Each of these vesicles contains an auditory rod, and is in communication with the auditory nerve through a delicate nerve-fibril. I have observed that each of these nerve-fibrils swells into a minute g

ese creatures during the mating season will for one instant deny; they hear r

correct one, for these organs unquestionably preside over alate equilibrium: they are true balancers. I do not propose to enter into any discussion as to whether these organs are rudimentary wings or not; suffice it to say that they appear to me to be organs fully developed and amply

n. Any derangement or disease of these canals interferes with equilibration; this is well shown

ger-in fact, of the entire family of Tabanid?, of the gall gnat (Diplosis resinicola, Comstock), and of the March flies (Bibionid?). These widely differing flies constitute the material

low, and receive into their hollows delicate nerve-fibrils. These nerve-fibrils pass inward toward the centre, and enter ganglia, which in turn are in immediate connection with the great nerves of the balancers. There is but one nerve in the insec

ily; hence, it is logically correct to conclude that the hollow hairs on the balancers of flies are likewise auditory hairs. Moreover, there are grouped about the bases of these knobbed organs certain rows of vesicles, whic

do not think that these have been pointed out before by any other observer) through which air passes into the large, vesicular cells which make up the greater portion of the knobs; spiracles

agonize Lee and others who consider them olfactory in character.[20] The position I take in

audition in these appendages.[21] But in Coleoptera my experiments and microscopical researches compel me to assert that I differ somewhat from the conclusions of the above-mentioned authorities. These gentlemen locate the ears of beetles also in their ante

When he touched the female she began to chirrup, whereupon the male turned his antenn? toward the box, "as if to determine from which direction t

same family (genus Prionus), and determined the true location of their ears by a system of rigid exclusion

r box in which she was confined. I then removed the antenn? of the male, and again made the female stri

, as Will supposed and as Lubbock advocates. I then removed the maxillary palpi of t

oved its labial palpi, leaving maxillary palpi and antenn? intact; it heard the female and made toward her.

nts; these, I take it, are auditory vesicles. In some of the Coleoptera I have found auditory rods in the apical segments, though this is by no means a comm

it were, and not absolutely necessary. It is a matter of easy demonstration to show that some of these insects hear less acutely where they are deprived of their antenn?. I pr

e senses have been so exhaustively treated by Lubbock in his Senses, Instincts, and Intelligences of Animals, that I could not hope to introduce an

to the knowledge already formulated, consequently I have treated these senses at some length. Technicalities and the detai

TNO

, N. Y. Medical Rec

, Animal L

auna of the Deep S

nstincts, and Intellig

illiant eggs, each in its own scarlet nest."-Lubbock, Sens

, loc. cit.

Animal Intel

azza, loc.

escent of Man,

ilton Gibson, Sh

ation of morphology, physiology, and psychology, as formulated in the first chapter of this work. This is one of the most important facts in the doctrine of evolution, and upon it is

Animal Life,

ux, Life in Ponds a

, Manual for the Stud

mstock, loc. ci

Dipteres; quoted also by Lubbock, Se

enn? of Insects, Ento

secten, Wiss. Zool.; quoted also by L