Francis Lieber.

Library of universal knowledge. A reprint of the last (1880) Edinburgh and London edition of Chambers' encyclopaedia, with copious additions by American editors (Volume 13) online

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Christian in doctrine as well as in heart. But his utterances vary as to doctrine; and in
a lecture on great men a few months after the former one, he seemed to place Christ on
a level with other benefactors of the race. At times he addresses Christ and speaks of
him in terms which exalt him into perfect divine sovereignty, and always his faith and
zeal seem characteristically Christian. He does not accept the organized ecclesiastical
Christianity of Europe and America, demanding for India a Christ presented in oriental
forms for the Hindu mind. His work is interesting, and fitted to secure sympathy from
Christians, who will be liable to misjudge his position if they forget the natural mysti-
cism, transcendentalism, and fervor of eastern thought and language, unfitted to respond
to the hard, clear, logical, dogmatic standards of the Anglo-Saxon.

SENLIS, a very ancient t. of France, dep. of Oise, 33 m. n.n.e. of Paris. Its older
portion is surrounded by walls. Hanked with 16 towers, which are all that remain out of
the 28 towers of early times. The cathedral, a small edifice, is a beautiful example of
early Gothic. Manufactures of cloth, lace, and thread are actively carried on. Pop.
'76, 6,537.

SENNA is one of the most important purgatives contained in our materia medica.
Two sorts of senna are recognized in the pharmacopoeia viz., Alexandrian senna and
Tinuevelly senna. The Alexandrian senna leaves are chiefly obtained from Cassia ln.n-
ceolata, while the Tinnevelly senna leaves are yielded by Camtia elongata. Alf.xmtdrimr
tenna is chiefly grown in Nubia and Upper Egypt, and is imported in large bales from
Alexandria. It is apt to be adulterated largely with the flowers, pods, and leaves of
Cynanchmn arghd and lephroxisi apollina. Tinnevetty or East Indiiin senna in odor and
taste entirely resembles Alexandrian senna. The leaflets are, however, "about 2 in.
long, lanceolate, acute, unequally oblique at the base, flexible, entire, green, without
any admixture."

Senna is, as Dr. Christison observes in his Dispensatory, "so certain, so manage-
able, and so convenient a purgative, that few remedies of its class are held in equal
estimation. In point of energy, it holds a middle place between the mild laxatives and
drastic cathartics. It acts chiefly on the small intestines, increasing their mucous secre
lion, as well as their peristaltic motion, and producing loose brown evacuationa" The



Snnaar.
Sensation.

drawbacks to its more universal administration are its disagreeable laste, and its ten-
dency to produce nausea, griping and flatulence; the means of collecting which are
subsequently noticed. The only circumstance povsitively contra-indicating its employ-
ment is an inflammatory state of the intestinal mucus membrane. Although senna has
been frequently submitted to chemical analysis, its active principle is not known; hut
whatever the cathartic principle may be, it is obviously absorbed into the circulation
before it begius to operate, since this drug imparts a purgative property to the milk of
nurses.

The following are the most important preparations of this medicine:

1. Infusion of ISenna, which is obtained by infusing for one hour, and then straining,
half an ounce of senna and half a dram of sliced ginger in half a pint of boiling
water. The taste of this" infusion is much concealed by the addition of some black tea,
or what Neligan finds " still better, coffee, and it may be sweetened with sugar, and milk-
added; it is in this way readily taken by children." The addition of neutral laxative
salts checks the griping, which is often caused by senna alone, and ut the same time
increases its activity. The ordinary black draught is commonly prepared by adding one
ounce of sulphate of magnesia to four ounces of infusion of senna. Two or three ounces
of this mixture, to which a dram each of the tinctures of senna and of cardamoms
may be added, usually act as a very viseful aperient.

2. Tincture of Senna, composed of senna, raisins, caraway seeds, and coriander seeds
macerated in proof-spirit, and formerly known as elixir sahitis, or the elixir of health, is
seldom given alone. Christison recommends a mixture of an ounce of the tincture of
senna with an ounce and a half of sulphate of magnesia, dissolved in four ounces of wattr,
and as much infusion of roses. "A wine glassful of this given every hour seldom fails lo
act with energy, and without sickness or tormina, and is an excellent combination for
most febrile disorders." The tincture is, however, most commonly prescribed in doses
of one or two drams, as an adjunct to other cathartic mixtures, lo correct their grip-
ing properties.

8. Confection of Senna, commonly known as lenitire electuary, is a pulpj- mixture of
powdered senna with powdered coriander seeds, figs, tamarinds, cassia pulp, prunes,
extract of liquorice and sugar; all of which substances are. under certain specified con-
ditions, combined by the action of boiling water. When properly prepared, which is
often not the case, it it forms a mild aperient, well suited for persons suffering from
piles.

In the above preparations, it is immaterial whether Alexandrian or East Indian senna
is employed.

The senna leaves of commerce and of medicine are the produce of several species of
Cassia (q.v.). natives of India, Arabia, Syria, and the n. of Africa. Cassia olorata is u
perennial herbaceous ] lant 1 to 2 ft. high, having smooth leaves, 6 or 7 pair of obovate
obtuse leaflets, racemes of yellow flowers, and curved, compressed pods, with an inter-
rupted ridge along the middle of each valve. It is found in Egypt and Nubia, ar.d is
now also cultivated in Italy, Spain, the West Indies, etc. C. acufifolia is a half-shrubby
plant, about 2 ft. high, with racemes of yellow flowers, lanceolate acute leaves, and Hat
elliptical pods, somewhat swollen by the seeds. It grows in the deserts near Assouan,
and the leaves are collected by the Arabs, and carried by n,erehants to Carlo for sale.
C. elongata is an annual with erect, smooth stem ; narrow leaves, with 4 to 8 pair of
lanceolate leaflets, which are ralher downy beneath; racemes of yellow flowers: and
eblong pods, quite straight, rounded at the apex, and tapering to the base. It grows in
India. C. athiopica is about 18 in. high, with 3 to 5 pair of oval-lanceolate, downy
leaflets; the pods flat and smooth. It grows in the n. of Africa. C. lancenlata is an
Arabian species, differing from the others in its erect pods. All these seem to furnish
the officinal senna. Linnaeus, not aware of the diversity of species, assigned it to one
which he named C. senna, but it would be hard to say which has a preferable claim to
this name.. All the species have the leaflets unequal sided, by which they are readily
distinguished from other leaflets often used for the adulteration of senna, as those of
argel (q.v.) and bladder senna. The commercial names of the different kinds of senna
do not seem in general to correspond with differences of species, but rather to refer to
the countries or ports from which they are brought.

BLADDER SENNA (Colu&a) is a genus of shrubs of the natural order legit mi nom, sub-
order papi!ionaca>, having pinnated leaves, red or yellow flowers, and remarkably inflated
pods, whence the English name. One species (U. frborctcem) is common in shrubberies
in Britain. It is a native of the s. of Europe, and is found on the ascent of the crater of
Mt. Vesuvius almost the only plant that exists there.

SENNAAR', lately a negro state, is now an Egyptian pashalik in the s. of Nubin.
The town from which it is named, Sennaar, near the Bahr-el-Azrek, and 160 m. s.s.e. of
Khartoum, was once a most important city, but is still a trading center of some consc
quence. Pop. about 10,000.

SENNACHERIB, an Assyrian king, son of Sargon, reigned 702-680 B.C. The interest
attaching to his name is principally due to the extraordinary and incomprehensible dis-
aster that befell his army, either at Libnah or at Pelasium, when no fewer than 185,000
Assyrians are said to have been slain by the "angel of the Lord" (see HEZEKIAH). The



OJ1 Sennaar.

Sensation*

Egyptian account of this mysterious affair (reported by Herodotus, book ii. 141), and
that of Berosus the Chaldaean, quoted by Joseplms (Antiq. of Jews, book x. chap. 1), as
well as the scriptural narrative (2 Kiugs, chap. 18) justify us in believing that Sennach-
erib at least sustained a sudden, unexpected, and terrible overthrow, which forced him
to retreat in hurried confusion to his own country. All that we know of his subse-
quent history is, that he was assassinated by his sons \vhile worshiping his favorite god.
The discrepancies, both as regards dates and names in the life of Sennacherib, between
the writer of Kings and profane historians, are felt, even by strenuous apologists like the
rev. George Rawliusou, to be almost, if not altogether, irreconcilable. Sennacherib
belongs to that showy class of eastern monarchs whose rule is commonly described as
"magnificent" i.e., he built great palaces, and erected monuments in the different
pirts of his empire, and everywhere left an impression of his grandeur. In Scripture,
IB Herodotus, in Josephus, Sennacherib is the "great king." Ilis most imperial work
was the palace at Koyunjik, which covered a space of more than 8 acres, and was richly
adorned with sculpture.

SENS, an old t. of France, in the department of Yonne, 70 m. s.e. of Paris, stands
mid pleasing scenery on the right bank of the Yonne. The town proper is surrounded
by walls, chiefly of Roman construction, and in the vicinity the remains of ancient
roads and of Roman camps abound. The spacious and handsome Gothic cathedral is
the principal edifice. An active trade in wines, grain, hemp, wool, and timber is car-
ried on. Pop. 76, 12,251.

SENSATION (in physiology) may be defined to be "the perception by the mind of a
change wrought in the body." According to this definition, which is borrowed from
Dr. Todd, sensation involves first, a bodily change from some cause, whether inherent
or external; and secondly, a mental change, whereby the perception of the bodily
ckange is accomplished. The true organ of sensation is the brain, and especially that
portion of it which (to use the words of the above-named eminent physiologist) consti-
tutes the center of sensation, and extends into the spinal cord, forming the posterior
horns of its gray matter. See SPIXAL, MAKKCT.V. Physiologists distinguish between
cvitim-on and special sensation. Common sensation exists in the skin, and in all parts of
the body to which ordinary sensory nerves are distributed, and is excited by ordinary
mechanical or chemical stimuli; while special sensation is exemplified in the special
senses of vision, hearing, etc. For the due action of the latter there are organs of spe-
cial sensation, which, by the peculiar character of the nerves with which they are sup-
plied, become the recipients of impressions of a particular kind; thus, the eye is sensible
to light, the ear to sound, etc.; and if the special nerves going to these organs be irri-
tated, instead of pain being excited, as in the case of an ordinary sensory nerve, there is
a feeling closely allied to that which would be excited by the application of the normal
stimulus, as light, sound, etc. Any ordinary sensibility those organs (the eye, ear, etc.)
possess is dependent ou ordinary sensory nerves, and is quite independent of the nerves
of special sense.

_ In works on the physiology of the nervous system, we often meet with the phrases
objective sensation, subjective sensation, and reflex sensation. We shall conclude this article
by a brief description of the meaning of these terms. " In the ordinary mode of exciting
ensations," says Dr. Todd. ' the presence of an object is necessary. This object cre-
ates an impression on the peripheral parts of the sensitive nerves; and the change caused
by this impression being duly propagated to the center of sensation, is perceived by the
mind." This, which is the ordinary form of sensation, is termed an object-ire sensation,
in opposition to a so-called subjective sensation, in which a mental act can develop a swi-
satipn independently of any present object. These subjective sensations are sometimes
excited by the mind recalling, more or less exactly, the presence of an object; but in
many cases they are caused by physical changes in the nerves themselves, owing to
an excess or deficiency of blood, or some other pathological causes. Thus disordered
conditions of the retina or optic nerve may give rise to motes or flashes of light;
disturbance of the auditory nerve occasions singing in the ears, the sound of dista*t
bells, etc.

To understand the mode in which reflex sensations are brought about, an acquaint-

rv* with mfl&X fi^.fi.nrt. Hpcr*riH.il in tlm nrtiflo ^TTTH-VC A x*i\ AT - i>\-/^T^o tt-v-o-rT?Ar io /-.i-,J



in the article NERVES AND XEKVOCS

site. As examples of this form of sensation may be mentioned the facts, that "the
irritation of a calculus in the bladder will give rise to pain in the thighs; that diseased
liver often excites pain in the shoulder- joint; and that ice or iced drinks suddenly intro-
duced iut the stomach occasion intense pain in the forehead. For further information
on the subject, the reader is referred to Dr. Todd's article "Sensation," in the 4th vol.
of his Cycloposdia, of Anatomy and Physiology.

SENSATION, a name of great import in the philosophy of mind, as well as familiar
in ordinary speech. In the mental process so named, there is a concurrence of many
contrasting phenomena, rendering the word ambiguous, and occasioning verbal
disputes.

1. In sensation there is a combination or concurrence of physical facts with a men-
tal fact, and the name is apt to be employed in expressing either side. Thus, in sight,
the physical processes are known to be "the action of light upon the globe and retina of



Sense*.
Sentence.

the eye, a series of nerve-currents in the brain, and a certain outgoing influence to mus-
cles and viscera; these are accompanied by the totally different phenomenon termed the
feeling, or the mental consciousness of light It is to the last fact, the mental fact, that
the name sensation is mo.-t correctly applied; but there is a natural liability to make it
include those physical adjuncts wh.ch are inseparable from the mental manifestations.

'2. In the still more comprehensive contrast of mind and the external or extended
world, both members may be designated under sensation. One and the same situation
on our part may contain a strictly mental or subjective experience pleasure or pain, for
example and an objective experience, or a recognition of the extended world, as distinct
from mind. In looking at a tine prospect, both tacts concur in fluctuating proportions;
A\e have a feeling of pleasure (mind or subject) and a knowledge of the outspread or
extended world (object), which is what affects us in the same way at all times, and affects
all minds alike. As before, sensation is most properly used to express the strictly mental
or subjective experience, the pleasure or the pain, while the " perception" should be
applied to express the objective experience. See PERCEPTION.

3. In sensation, a past experience recovered by memory is inextricably woven with
the present impression, a circumstance which contuses the boundary-line between sense
and intellect. The sensation that the full moon gives rise to is not solely owing to the
present effect of the moon's rays on the organs of vision ; the present offect revives or
restores the total ingrained impression of the moon consequent on all the occasions when
we have observed it. Again, it is impossible for us to have a sensation without a more
or less complex feeling of difference or discrimination, which property is a fundamental
fact of intellect. Onr sensation of the moon supposes a contrast of the white light with
the adjoining blue, of the round form with other forms, of the broad disk with a starry
point, and so on. Thus, in sensation we have a concurrence of all three processes of
the intellect retentiveness, agreement, and "difference. Sensation without intellect is a
mere abstraction ; it is never realized in fact.

This last remark has important bearings upon the question as to the origin of our
knowledge. It has been disputed whether or not our ideas arc wholly derived from
sense. Now, seeing that there is no such thing as sense to the exclusion of intellect, the
question ought to be enlarged and put in this form, Are our ideas wholly derived through
sense in conjunction with the intellectual processes, or are there any ideas that are not
or cannot be so derived? When it is alleged by Cudworth, Price, and others, by way of
maintaining the doctrine of innate ideas, that likeness, unlikeness. equality, proportion,
etc.. are not obtained from sense, the answer is, that their origin may in all probability
.be accounted for by sense co-operating with the Avell-known powers of the intellect, and
that, until the conjunction of the two is proved insufficient, the theory of an intuitive
origin is not called for.

SENSES. Referring for an account of the several senses to their respective designa-
tions, we will here endeavor to state what faculties or sensibilities of the mind are prop-
erly included under the name.

The common reckoning includes the five senses taste, smell, touch, hearing, sight
but this is not now considered exhaustive. or complete.

For example, the feelings of hunger, thirst, suffocation, internal warmth and chill-
ness, etc., have all the characters implied in an ordinary sensation: they arc the result
of some external agent acting on a distinct bodily organ, and giving rise to feeling, some-
times pleasurable and sometimes painful. In o'rder that these states, related to the
sensibility of the different viscera, may find a place among the senses, they have been
grouped under one general head, and designated "sensations of organic life." They are
of great importance as regards our enjoyments and our sufferings, although not con-
tributing mucli to our knowledge or intelligence. They approach nearest to taste nnrl
smell, tiie more emotional senses, and are at the furthest remove from the intellectual
senses touch, hearing, and sight.

Again, the feelings connected with our activity, or with the exercise of the muscular
organs as the pleasures of exercise and rest, the pains of fatigue, the sensibility to
weight, resistance, etc. were, until lately, overlooked in the philosophy of the mind.
When they began to be recognized it was common to treat them as a sixth sense, called
the muscular sense But this does not represent their true position. They do not, arise
from external agents operaling on a sensitive part, but from internal impulses proceed-
ing outward to stimulate the muscular energies and to bring about movements; they
are thus the contrast of the senses generally. Sense is associated with the in-going nerve-
currents, movement with the out-fjoinc/. "The contrast is vital and fundamental; and
accordingly the feelings of movement and muscular strain should be considered as a
genus distinct from the genus sense, and not as a species of that genus.

The classification of the fundamental sensibilities of the mind would then stand thus:
I. Feelings of muscular energy. II. Sensations of the senses: 1. Organic lift; 2. Taste;
8. Smell emotional; 4. Touch; 5. Hearing; 6. Sight intellectual.

SENSIBILITY is a term somewhat vaguely used by physiologists. Until a compara-
tively recent period it was often confounded with irritability, although Haller, more than
a century ago, very clearly laid down the distinction between these two properties of
tissues. We not unfrequeutly find it applied to nerves to signify their power of evolv-



Senses.
Seutetice*,

ing nervous force, but excitability (as Dr. Todd observes) more exactly implies what is
meant in this case. The lerni should he limited to signify the power which any part of
the body possesses of causing ehanues. inherent or excited in it, to be perceived by the
mind; and the greater this power is. the greater is the sensibility of the part. The degree
of sensibility of different parts of the outer surface of the body is very various. The
relative sensibility lias been ascertained by Weber by touching the surface with the
points of a pair of compasses tipped with cork, and then (the subject's eyes being closed)
by approximating the points until they were brought within the smallest distance at
which they could be felt to be separate. The following are a few of his results: Point
of tongue, ^ a line: tips of ringers, 1 line; red surface of lips, 2 lines; palmar surface of
2d phalanx. 2 lines; palmar surface of metacarpus. 3 lines; tip of the nose, 3 lines; palm
of the, hand, 5 lines; dorsum of the hand, 8 lines; vertex, 15 lines; skin over the spine
and the middle of the thigh, each ;JO lines; so that the sensibility of the skin is at least
sixty times gi eater in some parts than in others.

SENSITIVE PLANT, a name commonly given to certain species of mimosa, (see
), on account of the peculiar phenomena of irritability (q.v.) -which their leaves
exhibit, in their collapse when touched or shaken. Numerous species of ;/,//">,, po^es*
this property, and. indeed, most of the species in a greater or less degree; but those in
which it is most conspicuous are humble herbaceous or half-shrubby plants. They have
leaves beautifully divided, again and again pinnate, with a great number of small leaflets,
of which the pairs close upward when touched. On repeated or rougher touching, the
lc;:rle:s of the neighboring pin me also close together, and all the pinna; sink down, and
at last the leni'-stalk itself sinks down, and ti.o whole leaf hangs as if withered. If the
stern is shaken, all the leaves exhibit the same phenomena. After a short time the leaf-
stalk rises, and the leaflets expand again. On account of this curious and interesting
properly, some of the sensitive plants are frequently cultivated in our hot-houses. They
are generally treated as annuals, although capable of longer life. M. se/mitira, one of
the best-known species, is a native of Brazil, with prickly stems and leaf-1-huks. and
email heads of rose-colored flowers. JU. pudica has a herbaceous stem, bristly but not
prickly. -'/. 'tf<i. M. pubibundu, M. palupituns, and M. Viva are also among the most
sensitive species.

SENSO EH'M. This term is applied by physiologists to a series of ganglionic cenlers,
each of which has the power of communicating to the mind the impressions derived
from the organ with which it is connected, and of exciting automatic or involuntary
musoul.tr movements in respondence to these sensations. (Sec Carpenter On UK Func-
tions >f ///( Nwtotts System /// Hitman P/<i/xiol<>c/}/, 6th ed. p. 543.) These ganglionic
centers, which lie at the base of the brain in man, are in direct connection with the
nerves of sensation, and appear to differ entirely in their functions from the other parts
of the encephalon. Anterior, there are the of/active ganglia, or what are termed the
bulbs of the oll'jieiive nerves. The ganglionic nature of these structures is more evident
in many of the lower mammals, in whom the organ of smell is highly dcv< loped, than
it is in man. although even in the human subject these masses contain gray or vesicu-
lar nervous matter, indicating their true ganglionic nature. Behind these, we have the
optic ganglia, commonly k: -own as the corpora quadrigemina, small in man, but com-
paratively large in many of the lower mammals. The auditor)/ ganglia do not form dis-
tinct projecting masses, but, are represented by small masses of vesicular matter, into
which the auditory nerves may be traced, and which are imbedded in the medulla oblon-
gata. In fishes there is a well-developed and distinct auditory ganglion. The gitxtalory
gansrlion is the least distinct of any. but it is supposed to be represented by a mass of
vesicular matter imbedded, like the preceding ganglion, in the medulla oblongata, and
into which the nerves of taste may be traced. On examining a progressive series of
brains from man to the loAvest mammals, we find a continuous diminution of the hemi-
sphere sand a corresponding development, of these ganglia, or, at all events, of the olfac-
tory and optic ganglia; while, if we continue the investigation to the brains of birds,
reptile-, and fishes, we rind the same law in force, till finally, in reptiles and fishes, those
ganglia form the greatest part of the brain.



Online LibraryFrancis LieberLibrary of universal knowledge. A reprint of the last (1880) Edinburgh and London edition of Chambers' encyclopaedia, with copious additions by American editors (Volume 13) → online text (page 79 of 203)