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Scientific American Supplement, No. 520, December 19, 1885 online

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Mr. Lacaze Duthiers.

It only remains to express our hope that the aquarium may be soon
finished; but before this is done it will be necessary to get possession
of that unfortunate little road. After this final victory, Mr. Duthiers
in his turn will be able, amid his pupils, to enjoy all those advantages
of his work which he has until now offered to others, but from which he
himself has gained no benefit. - _La Nature._

* * * * *




THE MURÆNÆ AT THE BERLIN AQUARIUM.


Of all fish, eels are probably the most interesting, as the least is
known of them. Electricians are now examining the animal source of
electricity in the electric eel (Gymnotus electricus); zoologists are
still searching for the solution of the problem of the generation of
eels, of which no more is known than that the young eels are not born
alive; and numerous fishing societies are now studying the important
question of raising eels in ponds, lakes, etc., that are not connected
with the sea.

[Illustration: THE MURÆNÆ AT THE BERLIN AQUARIUM.]

The annexed cut, taken from the _Illustrirte Zeitung_, is a copy of a
drawing by Muetzel, and represents a group of Mediterranean Murænæ
(Muræna Helena). This fish attains a length of from 5 ft. to 6 ft., and
has a smooth, scaleless body of a dark color, on which large light-yellow
spots appear, which give the fish a very peculiar appearance. The
pectoral fin is missing, but it has the dorsal and anal fins, which it
uses with great ability. Its head is pointed, and its jaws are provided
with extraordinarily sharp teeth, which are inclined toward the rear; and
at each side of the head it is provided with a gill. The nostrils are on
the upper side of the snout, and a second, tubular, pair of nostrils is
located near the eyes. The bright eyes have a fierce expression, which
makes the fish appear very much like a snake. These fish are ravenous,
and devour crabs, snails, worms, and fishes, and if they have no other
food, bite off the tails of their brethren. They are caught in eel
baskets or cages, and by means of hooks; but they are rather dangerous to
handle, as they attack the fishermen and injure them severely.

Since the times of the ancients, Murænæ have been prized very highly on
account of their savory flesh. The Romans were great experts at feeding
these fish, Vidius Pollio being the master of them all, as he made a
practice of feeding his Murænæ with the flesh of slaves sentenced to
death. Pliny states that at Cæsar's triumphal entry Hirius furnished six
thousand Murænæ. Slaves were frequently driven into the ponds, and were
immediately attacked by the voracious fishes, and killed in a very short
time.

* * * * *




METAMORPHOSES OF ARCTIC INSECTS.


In the chapter entitled "Das insektenleben in arktischen ländern," which
Dr. Christopher Aurivillius contributes to the account of A.E.
Nordenskiöld's Arctic investigations, published this year in Leipzig,[2]
the author says: "The question of the mode of life of insects and of its
relation to their environment in the extreme north is one of especial
interest. Knowing, as we do, that any insect in the extreme north has at
the most not more than from four to six weeks in each year for its
development, we wonder how certain species can pass through their
metamorphosis in so short a period. R. McLachlan adverts, in his work
upon the insects of Grinnell Land, to the difficulties which the
shortness of the summer appears to put in the way of the development of
the insects, and expresses the belief that the metamorphosis which we are
accustomed here to see passed through in one summer there requires
several summers. The correctness of this supposition has been completely
shown by the interesting observations which G. Sandberg has made upon
species of lepidoptera in South Varanger, at 69° 40' north latitude.
Sandberg succeeded in following the development from the egg onward of
some species of the extreme north. _Oeneis bore_, Schn., a purely Arctic
butterfly, may be taken as an example. This species has never been found
outside of Arctic regions, and even there occurs only in places of purely
Arctic stamp. It flies from the middle of June onward, and lays its eggs
on different species of grass. The eggs hatch the same summer; the larva
hibernates under ground, continues eating and growing the next summer,
and does not even then reach its full development, but winters a second
time and pupates the following spring. The pupa, which in closely related
forms, in regions further to the south, is suspended free in the air upon
a blade of grass or like object, is in this case made in the ground,
which must be a very advantageous habit is so raw a climate. The imago
leaves the pupa after from five or six weeks, an uncommonly long period
for a butterfly. In more southern regions the butterfly pupa rests not
more than fourteen days in summer. The entire development, then, takes
place much more slowly than it does in regions further south. Sandberg
has shown, then, by this and other observations, that the Arctic summer,
even at 70° N., is not sufficient for the development of many
butterflies, but that they make use of two or more summers for it. If
then more than one summer is requisite for the metamorphosis of the
butterflies, it appears to me still more likely that the humble-bees need
more than one summer for their metamorphosis. With us only the developed
female lives over from one year to the next; in spring she builds the new
nest, lays eggs, and rears the larvæ which develop into the workers, who
immediately begin to help in the support of the family; finally, toward
autumn, males and females are developed. It seems scarcely credible that
all this can take place each summer in the same way in Grinnell Land, at
82° N., especially as the access to food must be more limited than it is
with us. The development of the humble-bee colony must surely be quite
different there. If it is not surely proved that the humble-bees occur at
so high latitudes, one would not, with a knowledge of their mode of life,
be inclined to believe that they could live under such conditions. They
seem, however, to have one advantage over their relatives in the south.
In the Arctic regions none of those parasites are found which in other
regions lessen their numbers, such as the _conopidæ_ among the flies, the
mutillas among the hymenoptera, and others." - _Psyche._

[Footnote 2: Nordenskiöld, A.E., Studien und forschungen veranlasst durch
meine reisen im hohen norden. Autorisirte ausgabe. Leipzig, Brockhaus,
1885, 9 + 581 pp., 8 pl., maps, O. il.]

* * * * *




A YEAR'S SCIENTIFIC PROGRESS IN NERVOUS AND MENTAL DISEASES.

[Footnote: Volunteer report presented to Nebraska State Medical
Society, May, 1885, at Grand Island, Neb.]

By L.A. MERRIAM, M.D., Omaha, Neb.,


Professor of the Principles and Practice of Medicine in the
University of Nebraska College of Medicine, Lincoln, Neb.

The records of the Nebraska State Medical Society show that the only
report of progress on nervous and mental diseases ever made in the
history of the society (sixteen years) was made by the writer last year;
and expecting that those appointed to make a report this year would,
judging by the history of the past, fail to prepare such a report, I have
seen fit to prepare a brief volunteer report of such items of progress as
have come to my notice during the last twelve months. I have not been
able to learn that any original work has been done in our State during
the past year, nor that those having charge of the insane hospital have
utilized the material at their command to add to the sum of our knowledge
of mental diseases.

Last year I said: "There is a growing sentiment that many diseases not
heretofore regarded as nervous (and perhaps all diseases) are of nervous
origin." This truth, that all pathologico-histological changes in the
tissues of the body are degenerative in character, and, whether caused by
a parasite, a poison, or some unknown influence, are first brought about
by or through a changed innervation, is one that is being accepted very
largely by the best men in the profession, and the accumulation of facts
is increasing rapidly, and the acceptance of this great truth will prove
to be little short of revolutionary in its influence on the treatment of
the disease. This is the outgrowth of the study of disease from the
standpoint of the evolution hypothesis. Derangements of function precede
abnormalities of structure; hence the innervation must be at fault before
the organ fails. Hence the art of healing should aim at grappling with
the neuroses first, for the local trophic changes, perverted secretions,
and structural abnormalities are the effects or symptoms, not the causes
of the disease. Dr. J.L. Thudicum has studied the chemical constitution
of the brain, and he holds that, "When the normal composition of the
brain shall be known to the uttermost item, then pathology can begin its
search for abnormal compounds or derangements of quantities." The great
diseases of the brain and spine, such as general paralysis, acute and
chronic mania, and others, the author believes will all be shown to be
connected with special chemical changes in neuroplasm, and that a
knowledge of the composition and properties of this tissue and of its
constituents will materially aid in devising modes of radical treatment
in cases in which, at present, only tentative symptomatic measures are
taken.

The whole drift of recent brain inquiry sets toward the notion that the
brain always acts as a whole, and that no part of it can be discharging
without altering the tensions of all the other parts; for an identical
feeling cannot recur, for it would have to recur in an unmodified brain,
which is an impossibility, since the structure of the brain itself is
continually growing different under the pressure of experience.

Insanity is a disease of the most highly differentiated parts of the
nervous system, in which the psychical functions, as thought, feeling,
and volition, are seriously impaired, revealing itself in a series of
mental phenomena. Institutions for the insane were at first founded for
public relief, and not to benefit the insane; but this idea has changed
in the past, and there is a growing feeling that a natural and domestic
abode, adapted to the varying severity of the different degrees of
insanity, should be the place for the insane, with some reference to
their wants and necessities, and that many patients (not all) could be
better treated in a domestic or segregate asylum than in the prison-like
structures that so often exist, and that the asylum should be as much
house-like and home-like in character as the nature of the insanity would
permit; while exercise and feeding are accounted as among the best
remedies in some cases of insanity, particularly in acute mania.

The new disease called morbus Thomsenii, of which I wrote in my report
last year, has been carefully studied by several men of eminence, and the
following conclusions have been reached as to its pathology: The weight
of the evidence seems to prove that it is of a neuropathic rather than a
myopathic nature, and that it depends on an exaggerated activity of the
nervous apparatus which produces muscular tone, and that it has much
analogy to the muscular phenomena of hysterical hypnosis, the genesis of
which is precisely explained by a functional hyperactivity of the nervous
centers of muscular activity. Until quite recently it was supposed that
the rhythmical action of the heart was entirely due to the periodical and
orderly discharge of motor nerve force in the nerve ganglia which are
scattered through the organ; but recent physiological observations, more
especially the brilliant researches of Graskell, seem to show that the
influence of the cardiac ganglia is not indispensable, and that the
muscular fiber itself, in some of the lower animals, at all events
possesses the power of rhythmical contraction.

Several valuable additions to our knowledge of the anatomy of the nervous
system have been made by Huschke, Exner, Fuchs, and Tuczek.

Tuczek and Fuchs have confirmed the discoveries of Exner, that there are
no medullated nerve fibers in the convolutions of the infant, and
Flechzig has developed this law, that "medullated nerve fibers appear
first in the region of the pyramidal tracts and corona radiata, and
extend from them to the convolutions and periphery of the brain," being
practically completed about the eighth year. This fact is of practical
importance in nervous and mental diseases, since it is becoming an
admitted truth that the histological changes in disease follow in an
inverse order the developmental processes taking place in the embryo.
Hence the recent physiological division of the nervous system by Dr.
Hughlings Jackson into highest, middle, and lowest centers, and the
evolution of the cerebro-spinal functions from the most automatic to the
least automatic, from the most simple to the most complex, from the most
organized to the least organized. In the recognition of this division we
have the promise of a steadier and more scientific advance, both in the
physiology and in the pathology of the nervous system.

Mr. Victor Horsley has recently demonstrated the existence of true
sensory nerves supplying the nerve trunks of nervi-nervorum.

Prof. Hamilton, of Aberdeen, claims that the corpus callosum is not a
commissure, but the decussation of cortical fibers on their way down to
enter the internal and external capsules of the opposite side.

Profs. Burt G. Wilder, of Ithaca, and T. Jefrie Parker, of New Zealand
Institute, have proposed a new nomenclature for macroscopic encephalic
anatomy, which, while seemingly imperfect in many respects, has, at
least, the merit of stimulating thought, and has given an impulse to a
reform which will not cease until something has been actually
accomplished in this direction. The object being to substitute for many
of the polynomial terms, technical and vernacular, now in use, technical
names which are brief and consist of a single word. This has already been
adopted by several neurologists, of whom we may mention Spitzka, Ramsey,
Wright, and H.T. Osborn.

Luys holds that the brain, as a whole, changes its position in the
cranial cavity according to different attitudes of the body, the free
spaces on the upper side being occupied by cerebro-spinal fluid, which,
obeying the laws of gravity, is displaced by the heavier brain substance
in different positions of the body.

Luys claims that momentary vertigo, often produced by changing from a
horizontal to a vertical position, seasickness, pain in movement in cases
of meningitis, epileptic attacks at night, etc., may be by this
explained. These views of Luys are accepted as true, but to a less extent
than taught by Luys. The prevalent idea that a lesion of one hemisphere
produces a paralysis upon the opposite side of the body alone is no
longer tenable, for each hemisphere is connected with both sides of the
body by motor tracts, the larger of the motor tracts decussating and the
smaller not decussating in the medulla. Hence a lesion of one hemisphere
produces paralysis upon the opposite side of the body. It has recently
been established that a lesion of one hemisphere in the visual area
produces, not blindness in the opposite eye, as was formerly supposed,
but a certain degree of blindness in both eyes, that in the opposite eye
being greater in extent than that in the eye of the same side. Analogy
would indicate that other sensations follow the same law, hence the
probability is that all the sensations from one side of the body do not
pass to the parietal cortex of the opposite side, but that, while the
majority so pass, a portion go up to the cortex of the same side from
which they come.

Dr. Hammond says that the chief feature of the new Siberian disease
called miryachit is, that the victims are obliged to mimic and execute
movements that they see in others, and which motions they are ordered to
execute.

Dr. Beard, in June, 1880, observed the same condition when traveling
among the Maine hunters, near Moosehead Lake. These men are called
jumpers, or jumping Frenchmen. Those subject to it start when any sudden
noise reaches the ears. It appears to be due to the fact that motor
impulse is excited by perceptions without the necessary concurrence of
the volition of the individual to cause the discharge, and are analogous
to epileptiform paroxysms due to reflex action.

The term spiritualism has come to signify more than has usually been
ascribed to it, for some recent authors are now using the term to denote
a neurosis or nervous affection peculiar to that class of people who
claim to be able to commune with the spirits of the dead.

Evidence obtained from clinical observations has tended of late to locate
the pathological lesions of chorea in the cerebral cortex.

Dr. Godlee's operation of removing a tumor from the brain marks an
important step in cerebral localization, and cerebral surgery bids fair
to take a prominent place in the treatment of mental diseases.

Wernicke has observed that the size of the occipital lobes is in
proportion to the size of the optic tracts, and that the occipital lobes
are the centers of vision.

Hughlings Jackson has observed that limited and general convulsions were
often produced by disease in the cortex of the so-called motor
convolutions. The sense of smell has been localized by Munk in the gyri
hippocampi, while the center of hearing has been demonstrated to be in
the temporal lobes. The center for the muscles of the face and tongue is
in the inferior part of the central convolution; that for the arm, in the
central part; that for the leg, in the superior part of the same
convolution; the center for the muscles and for general sensibility, in
the angular gyrus; and the center for the muscles of the trunk, in the
frontal lobes. In pure motor aphasia the lesion is in the posterior part
of the left third frontal convolution; in cases of pure sensory aphasia,
the lesion is in the left first temporal convolution.

The relation of the cerebrum to cutaneous diseases has been studied much
of late, and it is now held that the cutaneous eruptions are mainly due
to the degree of inhibiting effect exerted upon the vaso-motor center.

The relation of the spinal cord to skin eruptions has been more
thoroughly investigated and more abundant evidence supplied to
demonstrate the influence degeneration of the spinal cord has in causing
skin diseases, notably zoster, urticaria, and eczema.

This rheumatism, pneumonia, diabetes, and some kidney diseases and liver
affections are often the result of persistent nervous disturbance is now
held. That a high temperature (the highest recorded) has resulted from
injuries of the spinal cord, and where the influence of microzymes is
excluded, is not a matter of question. In one instance, the temperature
reached 122° F., and remained for seven weeks between 108° and 118° F.
The patient was a lady; the result was recovery. Hence it cannot be fever
which kills or produces rapid softening of the heart and other organs in
fatal cases of typhoid. Fever, so far as it consists in elevation of
temperature, can be a simple neurosis.

Many other items of progress might be presented did time permit,
particularly in the treatment of nervous affections, but this I leave for
another occasion.

* * * * *




SCARING THE BABY OUT.


Dr. Grangier, surgeon in the French army, writes from Algeria: "A few
days after the occupation of Brizerte, when the military authorities had
forbidden, under the severest penalties, the discharge of firearms within
the town, the whole garrison was awakened at three o'clock one morning by
the tremendous explosion of a heavily loaded gun in the neighborhood of
the ramparts; a guard of soldiers rushed into the house from whence the
sound had come, and found a woman lying on the floor with a newly born
babe between her thighs. The father of the child stood over his wife with
the smoking musket still in his hand, but his intentions in firing the
gun had been wholly medical, and not hostile to the French troops. The
husband discovered that his wife had been in labor for thirty-six hours.
Labor was slow and the contractions weak and far apart. He had thought it
advisable to provoke speedy contraction, and, following the Algerian
custom to _scare the baby_ out, he had fired the musket near his wife's
ear; instantanously the accouchement was terminated. After being
imprisoned twenty-four hours, the Arab was released." - _Cincinnati
Lancet._

* * * * *




"ELASTIC LIMIT" IN METAL.


The _Engineering and Mining Journal_ raises the question whether steel,
which is becoming so popular a substitute for wrought iron, will, when it
is subjected to continuous strain in suspension bridges and other similar
structures, do as well as iron has proved that it can. Recent tests of
sections from the cables at Fairmount Park, Philadelphia, and at Niagara
Falls show that long use has not materially changed the structure. The
_Journal_ says: "It is a serious question, and one which time only can
completely answer, whether steel structures will prove as uniformly and
permanently reliable as wrought iron has proved itself to be. In other
words, whether the fibrous texture of wrought iron can be equaled in this
respect by the granulated texture of steel or ingot iron. In this
connection it is interesting to note that the fibrous texture referred to
is imparted to wrought iron by the presence in it of a small proportion
of slag from the puddling furnace, and that this can be secured in the
Bessemer converter also if desired. The so-called _Klein-Bessemerei,_
carried on at Avesta in Sweden for several years past, produces an
exclusively soft, fibrous iron by the simple device of pouring slag and
iron together into the ingot mould. This requires however a very small
charge (usually not more than half a ton), and a direct pouring from the
converter, without the intervention of a ladle, which would chill the
slag."

The effect of the introduction of slag would seem to be to retrace the
steps usually taken in producing steel, viz., to separate the iron from
its impurities, and then to add definite quantities of carbon and such
other ingredients as are found to neutralize the effects of certain
impurities not fully removed.

The most intelligent engineers, after ascertaining by exhaustive physical
tests what they need, present their "requirements" to the iron and steel
makers, whose practical experience and science guide them in the
protracted metallurgical experiments necessary to find the exact process
required. The engineer verifies the product by further tests, and by
practical use may find that his "requirement" needs further
modifications. As a result of all this care, some degree of certainty is
secured as to what the material may be expected to do.

No doubt the chemical composition of the slag used at Avesta was known
and met some equally well known want in the iron, and thus the result
arrived at was one which had been definitely and intelligently sought.

An important factor in selecting material for the cables of suspension
bridges is its _true elastic limit_. By this term we mean the percentage
of the total strength of the material which it can exert continuously
without losing its resilience, i.e., its power to resume its former shape
and position when stress is removed. Now, in the case particularly of
steel wire as commonly furnished in spiral coils, the curve put into the
wire in the process of manufacture seriously diminishes this available
sustaining power.

For it is evident that it would be unsafe to subject these cables at any
time to a stress beyond their elastic limit. If, e.g., a snowstorm or a
great crowd of people should load a bridge beyond this limit, when the
extra weight was removed the cables could not bring the bridge back to
its normal place, and the result would be a permanent flattening and
weakening of the arch.

By a process invented and patented by Col. Paine, the wire in the New
York and Brooklyn bridge was furnished _straight_ instead of curved. Now,
if a short piece of common steel wire is taken from the coil, and pulled
toward a straight position, and then released, it springs back into its


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Online LibraryVariousScientific American Supplement, No. 520, December 19, 1885 → online text (page 8 of 9)