Scientific American Supplement, No. 303

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The uses to which this "dust" is put when ultimately fetched away are
surprising: without being freed from its organic refuse it is used to
fill up hollows in building-ground, and even for the repair of roads. A
few weeks ago I passed along a road which was being treated according
to the iniquity of Macadam. Over the broken stones had been shot, to
consolidate them, a complex of ashes, cabbage-leaves, egg and periwinkle
shells, straw, potato-parings, a dead kitten (over which a few
carrion-flies were hovering), and other promiscuous nuisances. The road
in question, be it remarked, is highly "respectable," if not actually
fashionable. The houses facing upon it are severely rated, and are
inhabited chiefly by "carriage people." What, then, may not be expected
in lower districts?

Much attention has lately been drawn to the fish trade of London. It has
_not_, however, come out in evidence that the fish retailers, if they
find a quantity of their perishable wares entering into decomposition,
send out late in the evening a messenger, who, watching his opportunity,
throws his burden down in some plot of building land, or over a fence.
When I say that I have seen in one place, close alongside a public
thoroughfare, a heap of about fifty herrings, in most active
putrefaction and buzzing with flies, and some days afterward, in another
place, some twenty soles, it will be understood that such nuisances
can only be occasioned by dealers. To get rid of, or at least greatly
diminish, carrion-flies, house-flies, and the whole class of winged
travelers in disease, it will be, before all things, essential to
abolish such loathsome malpractices. The dustbins must cease being made
the receptacle for putrescent and putrescible matter, the destruction of
which by fire should be insisted upon.

The banishment of slaughter-houses to some truly rural situation, where
the blood and offal could be at once utilized, would be another step
toward depriving flies of their pabulum in the larva state. An equally
important movement would be the substitution of steam or electricity for
horsepower in propelling tram-cars and other passenger carriages, with a
view to minimize the number of horses kept within greater London. Every
large stable is a focus of flies--_Journal of Science_.

* * * * *

ON THE RELATIONS OF MINUTE ORGANISMS TO CERTAIN SPECIFIC DISEASES.

At the recent Medical Congress in London, Professor Klebs undertook to
answer the question: "Are there specific organized causes of disease?"

A short historical review of the various opinions of mankind as to the
origin of disease led, the speaker thought, to the presumption that
these causes were specific and organized.

If we now, he said, consider the present state of this question, the
three following points of view present themselves as those from which
the subject may be regarded:

I.--We have to inquire whether the lower organisms, which are found in
the diseased body, may arise there spontaneously; or whether even they
may be regarded as regular constituents of the body.

II.--The morphological relations of these organisms have to be
investigated, and their specific nature in the different morbid
processes has to be determined.

III.--We have to inquire into their biological relations, their
development inside and outside the body, and the conditions under which
they are able to penetrate into the body, and there to set up disease.

_First_.--With regard to the first question, that of the possibility of
spontaneous generation, the speaker gave a decided negative.

_Second and third_.--There is in microscopic organisms a difference of
form corresponding, as a rule, to difference of function. The facts
regarding these various lower forms are briefly reviewed.

"Three groups of hyphomycetae, algae, and schizomycetae, have been
demonstrated to occur in the animal and human organism in infective
diseases. Their significance increases with the increase of their
capacity for development in the animal body. This depends partly upon
their natural or ordinary conditions of life, but partly also, and that
in a very high degree, upon their power of adaptation, which, as Darwin
has shown, is a property of all living things, and causes the production
of new species with new active functions.

"1. The hyphomycetae, on account of their needing an abundant supply
of oxygen, give rise to but few morbid processes, and these run their
course on the surface of the body, and are hence relatively of less
importance. It will be sufficient here to refer to the forms, achorion,
trichophyton, oidium, aspergillus, and the diseases produced by them,
favus, ringworm, and thrush, to show this peculiarity. Nevertheless, we
see that these organisms also (as was proved by the older observations
of Hannover and Zenker) may, under certain circumstances, penetrate into
the interior of the organs. Grawitz, moreover, has recently shown that
their faculty of penetrating into the interior of the organism, and
there undergoing further development, depends on their becoming
accustomed to nitrogenous food.

"2. Only one of the algae, viz., leptothrix, has as yet acquired any
importance as a producer of disease. It gives rise to the formation of
concretions, and that not only in the mouth, but also, as I have shown,
in the salivary ducts and urinary bladder.

"Another alga, the sarcina of Goodsir, may indeed pass through the
organism, without, however, producing in its passage either direct
or indirect disturbances. It seems more worthy of note that many
schizomycetae, and especially the group of bacilli, are evidently nearly
allied to the algae in their morphological and vegetative relations--so
as to be assigned to this class by several authors, and especially by
Cienkowski.

"The schizomycetae furnish, without doubt, by far the most numerous
group of infective diseases. We distinguish within this group two
widely different series of forms, which we will speak of as bacilli and
cocco-bacteria respectively. The former, which was first exhaustively
described by Ferdinand Cohn, and the pathological importance of which,
especially in relation to the splenic disease of cattle, was first shown
by Koch, consist of threads, in the interior of which permanent or
resting-spores are developed. These spores becoming free, are able,
under suitable conditions of life, again to develop into threads. The
whole development of these organisms, and especially the formation
of spores, is completed on the surface of the fluids, and under the
influence of an abundant supply of oxygen.

"The number of affections in which these organisms have been found,
and which may be to a certain extent produced artificially by the
introduction of these organisms into healthy animal bodies, has been
largely increased since the discovery of Koch, that the bacteria of
splenic fever (anthrax) belong to this group. Under this head must be
placed the bacillus malarise (Klebs and Tommassi-Crudeli), the bacillus
typhi abdominalis (Klebs, Ebert), the bacillus typhi exanthematici
(Klebs, observations not yet published), the bacillus of hog-cholera
(Klein), and, finally the bacillus leprosus (Neisser). It would exceed
the time appointed were I to attempt to describe these forms more
minutely. This may, perhaps, be better reserved for discussion and
demonstration.

"Alongside of these general infective diseases produced by bacilli,
local affections also occur, which indicate the presence of these
organisms at the point where disease begins. As an example of these
processes, which probably occur in various organs, I would mention
gastritis bacillaris, of which I shall show you preparations. In this,
we can trace the entrance of the bacilli into the peptic glands, as well
as their further distribution in the walls of the stomach, and in the
vascular system.

"The second group of the pathogenetic schizomycetae I propose to call,
with Billroth, cocco-bacteria, because they consist of collections of
micrococci, which are capable of transforming themselves into short
rods. The former usually form groups united by zooegloea; by prolongation
of the cocci rods are formed, which sprout out, break up by division
into chains, and further lead again to the formation of resting masses
of cocci. I distinguish, further, in this group, two genera--the
microsporina and the monadina; in the former of which the micrococci are
collected into spherical lumps, in the latter into layers. The one class
is developed in artificial cultivation fluid, the other on the surface.
The former requires a medium poor in oxygen, the latter a medium rich in
oxygen, for their development.

"Among the affections produced by microsporina, I reckon especially the
septic processes, and also true diphtheria. On the other hand, to the
processes produced by monadina belong especially a large series of
diseases, which according to their clinical and anatomical features,
may be characterized as inflammatory processes, acute exanthemata, and
infective tumors, or leucocytoses. Of inflammatory processes, those
belong here which do not generally lead to suppuration, such as
rheumatic affections, including the heart, kidney, and liver affections,
which accompany this process, sequelae which, as is well known,
lead more especially to formation of connective tissue, and not to
suppuration. Here, also, belong croupous pneumonia, the allied disease
erysipelas, certain puerperal processes, and finally, parotitis
epidemica, or mumps.

"Among the acute exanthemata, the following may, up to the present time,
be placed in this group; variola-vaccina, scarlatina, and measles.

"The group of infective tumors is represented by tuberculosis, syphilis,
and glanders. Throughout the whole group of cocco-bacteria the
demonstration of organisms in the diseased parts encounters difficulties
which vary considerably in the different kinds."

The speaker concluded by describing the methods (now well known) by
which the powers of the different organisms are tested.

He also referred to Pasteur's, Chauveau's, and Toussaint's recent
experiments.

His conclusion was that the specific communicable diseases are produced
by specific organisms.

* * * * *

THE CENTENARY OF THE DISCOVERY OF URANUS.

By W. F. DENNING, F.R.A.S.

The year 1781 was signalized by an astronomical discovery of great
importance, and one which marked the epoch as memorable in the annals
of science. A musician at Bath, William Herschel by name, who had been
constructing some excellent telescopes and making a systematic survey of
the heavens, observed an object on the night of March 13 of that year,
which ultimately proved to be a large planet revolving in an orbit
exterior to that of Saturn. The discovery was as unique as it was
significant. Only five planets, in addition to the Earth, had hitherto
been known; they were observed by the ancients, and by each succeeding
generation, but now a new light burst upon men. The genius of Herschel
had singled out from the host of stars which his telescope revealed
an object the true character of which had evaded human perception for
thousands of years!

[Illustration: FIG. 1.--APPROXIMATE PLACE OF URANUS AMONGST THE STARS AT
ITS DISCOVERY ON MARCH 13, 1781]

The centenary of this remarkable advance in knowledge naturally recalls
to mind the circumstances of the discovery, and makes us inquisitive to
know what new facts have been gleaned of Herschel's planet, now that
a hundred years have passed away, and we are enabled to look back and
review the vast amount of labor which has been accomplished in this wide
and attractive field of astronomical research. We may learn what new
features have been discerned of the new body, and what additional
discoveries in connection with other planets unknown in Herschel's day,
have been effected by aid of the powerful telescopes which have been
devoted to the work. We do not, however, intend dealing with the general
question of planetary discovery, for at a glance we are impressed with
its magnitude. While a century ago five planets only were known, we now
have some two hundred and thirty of these bodies, and the stream of
discovery flows on without abatement through each succeeding year. The
detection of Uranus seems, indeed, to have been the prelude to many
similar discoveries, and to have offered the incentive to greater
diligence and energy on the part of observers in various parts of the
world.

[Illustration: Fig. 2.--ORBITS OF THE URANIAN SATELLITES.]

Many great discoveries have resulted from accident; and the leading
facts attending that of Uranus prove that, in a large measure, the
result was brought about in a similar way. Herschel, as he unwearyingly
swept the heavens night after night, was in quest of sidereal
wonders--such as double stars and nebulae--and he happened to alight
upon the new planet in a purely chance way. He had no expectation of
finding such a remarkable object, and indeed, when he had found it,
wholly mistook its character. There could be no doubt that it was a body
wholly dissimilar to the fixed stars, and it was equally certain that it
could not be a nebula. It had a perceptible disk, for when it had first
come under the critical eye of its discoverer he had noticed immediately
that its appearance differed widely from the multitude of objects which
crossed the field of his telescope. He had been accustomed to see hosts
of stars pass in review, and their aspect was in one respect similar,
namely, they were invariably presented as points of light incapable of
being sensibly magnified, even with the highest powers. True, there was
a great variety of apparent brightness in these objects and a singular
diversity of configuration, but there was no exception to the invariable
feature referred to. The point of light was constant, and no striking
exception was anticipated until one night--March 13, 1781--Herschel
being intently engaged in the examination of some small stars in the
region of Gemini, brought an object under the range of, his telescope,
which his eye at once selected as one of anomalous character.

Applying a higher power, he noticed that it exhibited a planetary disk,
but his instrument failed to define it with sufficient distinctness, and
hence he became doubtful as to its real nature. The object was found to
be in motion, and subsequent observations led him to the assumption that
it must be a comet of rather exceptional type. This appeared to be the
best explanation of the strange body, for history contained many records
of curious comets, some of which were observed as nearly circular
patches of nebulous light, and probably of similar aspect to the object
then visible; and apart from this it must be remembered that the idea of
a large planet exterior to Saturn was a fact of such momentous import
that Herschel, with a due regard to that modesty which accompanies
true genius, refrained from attaching such an interpretation to his
observations. He was content to direct the notice of astronomers to it
as a phenomenon requiring close attention, and suggested that it might
be a comet in consequence of its motion and the faint and somewhat
ill-defined character of its appearance.

From the earliest ages five planets only were known, and the discovery
of another large planet beyond the sphere of Saturn must at once
revolutionize existing ideas as to the range of the solar system, and
immediately take rank as a scientific event of equal interest to the
discovery of the moons of Jupiter or the rings of Saturn, which each in
their day impressed men with new ideas of the celestial mechanism. But
the truth could not long be delayed. The new body being watched and its
orbit rigorously computed from a series of observed positions revealed
its true character, and Herschel was awarded the honor due to the author
of a discovery of such importance. His diligence and pertinacity alone
had enabled him to search out from among the multitude of stars thickly
strewn over the firmament this unknown and well-nigh invisible planet
which, during all the preceding years of the world's history, had eluded
human perception. Men had been all unconscious of its existence as it
had been slowly completing its circuits around the sun, obedient to the
same laws as the other planets of the solar system, and awaiting the
hour when the unfailing eve of Herschel should introduce it as the faint
and far-off planet girding our system within its expansive folds.

As soon as the existence of the new orb was confirmed and the fact
rendered indisputable, the question naturally arose whether it had ever
been seen in former years by the authors of star catalogues, who could
hardly have overlooked an object like this though its planetary nature
had manifestly escaped detection. It was just perceptible to the naked
eye, shining like a star of the sixth magnitude, and ought to have been
distinguished by those who had reviewed the heavens with the purpose
of determining and mapping the positions of the stars. Reference was,
therefore, made to the chief catalogues, when it was found at once that
the planet had been unquestionably observed by Tobias Mayer, Le Monnier,
Bradley, and Flamsteed. It was several times noted by these observers:
by Le Monnier no less than twelve times, and by Flamsteed on six
occasions; and it is remarkable that in every instance its true
character escaped detection. Neither its special appearance nor its
motion attracted attention, so that it was merely catalogued as an
ordinary fixed star. Thus Herschel was not anticipated in his discovery.
It remained for him, in 1781, to note its exceptional aspect, and to
specify it as an object requiring critical investigation. But the early
observations above alluded to served a useful purpose in testing the
accuracy of the computed orbit, for without waiting many years to
compare the theoretical and observed positions, astronomers had in these
old records a reliable series of points through which the previous
course of the planet could be traced.

The calculations showed that its mean distance from the sun was some
1,750,000,000 miles, and that a revolution was completed in about
eighty-four years. It was also found to be a very large planet, greatly
exceeding either Mercury, Venus, the Earth, or Mars, though considerably
inferior to either Jupiter or Saturn.

Here, then, was a discovery of the utmost importance, and one of the
most salient additions to our knowledge which the telescope had ever
achieved. The new planet was now definitely assigned its proper place in
the solar system, and was regarded as of equal significance with the
old planets. True, the new planet of Herschel could not be compared as
regards its visible aspect with the other previously known members of
our system, but it was nevertheless an object of equal weight. Its vast
distance alone rendered it faint. It formed one of the constituent parts
of the solar system, which, though separated by immense intervals of
space, are yet coherent by the far-reaching effects of gravitation.
There is, indeed, a bond of harmony between the series of planetary
orbits, which exhibit a marked degree of regularity in their successive
distances from the sun; and though they are not connected by any visible
links, they are firmly held together by unseen influences, and their
motions are subject to certain laws which have been revealed by
centuries of observation.

The question of suitably naming the new planet soon came to the fore.
Herschel himself proposed to designate it the "Georgium Sidus," in honor
of his patron, George III., just as Galileo had called the satellites
of Jupiter the "Medicean stars," after Cosmo de' Medici. But La Place
proposed that the planet should be named after its discoverer; and thus
it was frequently referred to as "Herschel," and sometimes as "The
Herschelian planet." Astronomers on the continent objected to this
system of personal nomenclature, and argued that the new body should
receive an appellative in accordance with those adopted for the old
planets, which had been selected from the heathen mythology. Several
names were suggested as suitable (on the basis of this principle), and
ultimately the one advanced by Bode received the most favor, and the
planet thereafter was called "Uranus."

The varying positions of the new body as observed on successive nights
were determined by comparisons with a group of six small stars, termed
by Herschel [Greek: alpha, beta, gamma, delta, epsilon] and afterwards
formed into a constellation under the designation of "Britannia," though
it does not appear that this little asterism is acknowledged as one of
our constellations. Its position is about midway between Taurus and
Gemini, and the following are the principal stars computed for 1881.0,
as given by Mr. Marth:

Star. Magnitude. Right Ascension. Declination.
h. m. s.
alpha 9.0 5 42 6.06 23 deg. 35' 6.7" N.
eta 8.7 5 43 17.82 23 26' 7.2 N.
theta 8.8 5 44 0.99 23 53' 30.8 N.
epsilon 8.8 5 45 40.68 23 34' 46.8 N.

The stars are therefore merely telescopic, and are confined to a small
area of space, so that the propriety of adopting the group as a distinct
constellation is very questionable. Their positions close to Uranus at
the time of its discovery, and the fact that the planet's motion was
detected by means of comparisons with them, has given to these stars an
historical interest which in future years must often attract the student
to their reobservation. But it would be unwise, as forming a bad
precedent, to accept a group of stars of this inferior type as meriting
to rank among the old constellations, when we have numbers of richer
groups, situated on their confines, which first deserve such a
distinction. However special or unique the circumstances connected with
certain telescopic stars may be, and however necessary it may appear
to signalize them by a specific title, we are inclined to question the
adoption of such means as likely to exercise a wrong influence,
inasmuch as it may hereafter originate further innovations of a similar
character, and ultimate complications will be certain to arise.

Soon after the discovery of Uranus it was suspected that the planet
was encircled, like Saturn, by a luminous ring, but on subsequent
observation this was not confirmed, and no such appendage has ever been
revealed in the more perfected instruments of our own times. Indeed, if
Uranus displays a peculiarity of constitution in any way analogous to
the ring system of Saturn, it must be of the most minute character so as
to have thus evaded telescopic scrutiny during a hundred years.

The discovery soon attracted the notice of royalty, and the reigning
sovereign, George III., anxious to practically express his appreciation
of the valuable labors of Herschel, awarded him a pension of L200 a year
and furnished him with a residence at Slough, near Windsor, and the
means to erect a gigantic telescope with which he might be enabled
to continue his important researches. This instrument consisted of a
reflector on the "Front-view" construction, with a speculum 4 feet in
diameter and of 40 feet focal length. Upon its completion, Herschel
immediately began to observe the region of the new planet with the idea
of discovering any satellites which might belong to it, for analogy
suggested that it was surrounded by a numerous retinue of such bodies.
He was soon successful, for, on the night of January 11, 1787. he saw
two minute objects near the planet, which renewed observations revealed
to be satellites; and he detected two additional ones in 1790, and two
others in 1794, making six in all. But the observations were of extreme
difficulty. The path of the planet frequently passed near minute stars,
and it became hard to distinguish between them and the suspected
satellites. Herschel, however, considered he had obtained conclusive
evidence of the existence of six satellites with sidereal periods
ranging from 5d. 21h. 25m. to 107d. 16h. 39m., and his means of
observation being much superior to those possessed by any of his
contemporaries it was impossible to have corroborative testimony.

The matter was thus allowed to rest until the middle of the present
century, when Lassell, in the pure sky at Malta, endeavored to reobserve
the satellites with a two-foot reflector. This instrument was considered
superior to Herschel's telescope; and the atmosphere at this station
being decidedly more suitable for such delicate observations than
in England, it was removed there for the express purpose of dealing
successfully with objects of extreme difficulty. The results were very
important. Mr. Lassell became convinced that Uranus had only four
satellites, and that if any others existed they remained to be
discovered. Two of these were found to be identical with those seen by
Herschel in 1787, and now called Titania and Oberon. The other two,
Ariel and Umbriel, could not be identified with any of those alleged to
have been previously detected by Herschel, so that the inference was
that they were new bodies, and that the priority of discovery was due to
Mr. Lassell; whence it also followed that the older observations were
erroneous, and that in fact Herschel had been entirely mistaken with
regard to the four satellites he believed he had detected subsequently
to 1787.

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