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THE MONTHLY
MICROSCOPICAL JOURNAL:

TRANSACTIONS

OF THE

ROYAL MICROSCOPICAL SOCIETY,

AND

RECORD OF HISTOLOGICAL RESEARCH

AT HOME AND ABROAD.

EDITED BY

HENRY LAWSON, M.D., F.R.MS.,

Assistant Physician to, and Lecturer on Histology in, St. Mary’s Hospital,

VOLUME II.

LONDON:
ROBERT HARDWICKE, 192, PICCADILLY, W.

MDCCCLXIX.

(Mag
NOV 29 1957

LIBRARY

LONDON: PRINTED BY W. CLOWES AND SONS, STAMFORD STREET AND CHARING CROSS.

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MONTHLY MICROSCOPICAL JOURNAL.

JULY 1, 1869.

I.—On the Rectal Papille of the Fly.
By B. 'T. Lowyz, MRCS.
(Read before the Rovau Microscoricat Society, May 12, 1869.)

THE organs for which I have retained the name given to them by
Weismann, are four in number, situated near the termination of the
alimentary canal. They are hollow, conical, glandular organs, about
goth of an inch in length, enclosed in a dilatation of the rectum, and
having their bases only external to its cavity. I think I shall be
able to show that their function is the excretion of a urinary fluid ;
I have, however, retained an anatomical name, instead of giving
them a physiological one, because its applicability is obvious, and
admits of no difference of opinion; it is not a new name; and,
lastly, had I called them kidneys, or even renal organs, I should
have been comparing them to the totally dissimilar structures found
in vertebrates.

Each papilla consists of three parts: an internal central cavity,
surrounded by a transparent structureless membrane; around this
a hollow cone of gland cells, the secreting portion of the organ, is
disposed ; and external to this again, a tough transparent cone of
membrane, which I shall call the calyx of the papilla, perforated by
numerous minute pores, surrounds the whole of that portion of the
organ which is internal to the rectum. By alittle dexterous mani-
pulation these parts may be separated completely from each other

DESCRIPTION OF PLATE XVIII.

Fig. 1.—The rectum with its papille.
», 2.—Base of a papilla, showing the muscular layer x 75 diam.
», 3.—A flattened muscular band from the same x 250 diam.
» 4.—Calyx of the papilla x 75 diam.
», .—Central cavity and portion of the gland structure x 75 diam.
5, 6.—Apex of the calyx x 250 diam.
7.—Base of a papilla, the muscular layer removed, showing the arrangement
of the trachee.
», 8.—Transverse section through the middle of a papilla x 75 diam.
», 9.—Crystals of uric acid from the urinary secretion of the fly.

VOL. II, B

- Transactions of the leet ie ice
(Plate XVIIT., Figs. 4, 5); or, by hardening the papille in chromic
acid, sections may be made showing the relations of the parts in situ.
Fig. 8 represents such a section.

The calyx (Fig. 4) is perforated by about 300 minute pores,
each pore being surrounded by a nipple-like projection, which is
surmounted by from three to eight minute sete (Fig. 6). The
whole membrane of the calyx becomes thickened towards the apex,
where it has a faint, yellow tint; it is near the apex that the
nipple-like projections and their sete are best seen, indeed a casual
observer might overlook their presence entirely at the upper portion
of the calyx.

The calyx itself is marked by faint reticulations, and its margin
is deeply crenated. These are the only indications of structure
which it presents, and these seem to point to its being a fibrous
membrane, especially as two sets of muscular fibres arise from the
crenations of its margin.

These muscular fibres are, first, a set from the muscular coat of
the rectum, and, secondly, a layer of converging fibres which cover
the whole base of the papilla to within a very short distance of its
centre, and which apparently end in the edge of the membrane
forming the boundary of the central cavity, although from the
extreme transparency of this membrane it is nearly impossible to
be certain of their insertion (Fig. 2).

Each papilla is supplied with air by a large tracheal vessel from
the last abdominal spiracle, which divides into several—generally
five or six—large trunks before entering the papilla. The trachex
of the papilla may be divided into two sets as soon as they enter
the base of the organ ; first, from twenty to thirty radiating lateral
branches which run to the edge of the base (Fig. 7), and then pass
over the outer surface of the glandular structure to the apex of
the cone, giving off numerous branches, which anastomose freely,
and form a fine reticulation around the gland cells, the larger
branches running directly towards the central cavity, and forming
loops by anastomosing with other similar vessels (Fig. 8).

The second set are the terminations of the main trachezx : after
giving off the lateral branches these run directly into the central
cavity, where they become tortuous, and anastomose with each
other, giving off comparatively few small vessels in proportion to
their size, and forming a network which fills the central cavity, but
none of their branches pierce its mvesting membrane anywhere.
Fig. 5 represents the central cavity with its trachez, with a small
portion of the lateral branches and their terminations amongst the
glandular structure.

Each papilla receives two or three nerve filaments from one of
a pair of nerves given off at the termination of the ventral cord,
which are distributed to the muscular coat of the rectum; a few

Mourne), July a woo | Leoyal Microscopical Society. 3

very small filaments appear to accompany the trachez into the
central cavity.

The gland cells are large—about 3}5th of an inch in diameter—
and slightly angular by mutual pressure; each contains a granular
nucleus about one-third the diameter of the cell.

In order to understand the functions of these organs it will be
necessary to investigate briefly the structure of that portion of
the alimentary canal which encloses them. About two lines above
the anal orifice a sphincter, or rather a kind of muscular valve,
closes the intestine (Fig. 1, a). A little below this the rectum
becomes much dilated, and its muscular coat correspondingly
attenuated ; when the insect first emerges from the pupa case this
dilatation is filled with a semi-solid mass of uric acid. I have never
found any of this substance above the valve I have just described—
an important fact in relation to the function of the rectal papille.

There is nothing new in the fact that insects excrete uric acid ;
figures of crystals of this substance from the excrement of the
clothes-moth and stag-beetle will be found in the ‘ Micrographic
Dictionary. I have given figures of several forms from that of
the fly (Fig. 9); the only question is by what structure is this
substance eliminated.

There are only two gland structures which open into the
alimentary canal of the fly—the rectal papillee and the malpighian or
liver-tubes ; these latter, beside opening into the intestines more
than two lines above the valve I have described, contain cells which
from their contents—oil-globules and yellow pigment—are unmis-
takably liver-cells. I have compared these carefully with cells
from the liver of the bullock, and could see no difference except
that those of the latter animal contained more and larger oil-
globules than are present in the liver-cells of the fly. Hence I
conclude that we must not look to the malpighian tubes for the
origin of the urinary secretion.

On the other hand, the structure of the rectal papille is just
such as we might expect to find in a renal organ. If I am right in
my belief that the central cavity is continuous with the visceral
cavity, it affords a mean of bringing the circulating fluid into
almost immediate contact with the secreting cells, a fine structure-
less membrane only, being interposed—still further I believe I am
justified in asserting that the circulating fluid is expelled from, and
a fresh supply is drawn into, the céntral cavity by a rhythmic
muscular act.

In the female fly the rectal papille lie fortunately between the
second and third rings of the ovipositor when that organ is exserted,
where it is sufficiently transparent to allow of the papille being
seen during life. I have repeatedly observed a movement of the
kind I have described. I believe this is the explanation of the

B 2

4 Transactions of the Deas gue

radiating bands of muscle at the base of the papille ; they probably
open the central cavity, and at the same time press upon the
contents of the papille, and, assisted by the muscular wall of the
rectum, which contracts at the same instant, they not only expel
the contents of the central cavity, but also press the secreted fluid
through the minute pores in the calyx into the cavity of the rectum ;
the en cavity is probably refilled by the elasticity of the calyx
itself.

There is no trace of these organs in the maggot, and at present I
cannot state at what precise period they first appear in the pupa,
but as soon as the embryo fly, if I may be allowed the expression,
has become so far developed that its principal parts may be easily:
recognized, about the end of the second or the beginning of the
third week of the pupa state, the calices of these organs are already
formed and filled with gland-cells, larger than those in the adult
fly, but otherwise similar ; the tracheal vessels are quite rudimentary
and very transparent, and the calices themselves are striated coarsely,
but exhibit the nipple-like pores so characteristic of them. No
muscular fibres are then distinctly traceable, but their position is
marked by the presence of rapidly growing cells.

With regard to the urinary secretion itself, that passed by the
insect when it first emerges from the pupa case is a semi-solid mass
of nearly pure uric acid; that passed afterwards is a turbid fluid,
sometimes almost clear, and very irritating when applied to any
tender part of the skin: this fluid deposits an abundance of crystals
of uric acid when acidulated with hydrochloric or nitric acids. Fig. 9
represents the principal forms of these crystals. I believe the acid
is held in solution by ammonia, but of this I am not certain. The
excrement of the fly when heated over a lamp gives off a strong
urinary smell,

‘Monthly Mi ical , , ,
fonthly, Microscopical) — Royal Microscopical Society. 5

Il—On the Diatom Prism, and the True Form of Diatom
Markings. By the Rev. J. B. Ruapg, M.A., F.B.S., President
of the Royal Microscopical Society.

(Read before the Royau Microscopicau Society, June 9, 1869.)

Tux pages of our Transactions, from the commencement of our
Society to the present time, bear ample evidence of the interest
which is taken in the structure of the Diatom-valve, and of the
Protean aspects which different observers have confidently recorded
under different methods of illumination. In venturing to propose
a new method of illumination and to describe new results, I must
be permitted to copy the confidence of those who have preceded
me, and to say that the usual methods of illumination are wrong in
principle, and the consequent descriptions of the form of Diatom
Markings are wrong in detail. But this, says one of my friends, is
“ao, startler,” and we all have to go to school again. I can only
reply, that I have never left school, and the new lesson I have
just learnt is not one of least interest, for it 1s admitted by those
who have bestowed no unworthy labour on the minute structure of
the diatom-valve, that the correct exposition of the structure
involves a question quite as important, perhaps, as any we have to
encounter in the whole course of vegetable physiology. It was
only when I was imposed upon by lines, z.e. when I was taught to
believe that on the valve of P. angulatum, for instance, there are
sets of three lines in the direction of the sides of an equilateral
triangle, and formed by probably elevated ridges, that I proposed
to obtain their shadows, not by a circle of ight, as in the common
“stop lens,” but by three separate points of light of proper intensity
in the kettledrum, to be placed by the revolution of the sub-stage
at right-angles to the lines to be resolved; and if this were the
true structure, the principle of illumination is correct. The result
also appeared to be satisfactory. The lines of shadows were readily
made out, with the due arrangement of hexagonal markings, formed
by the crossing of two equilateral triangles of these shadow-lines ;
but, after all, so far as the eye was concerned, there was only an
illustration of Berkeley’s theory of “ No matter,’—shadow, without
the substance. I have, however, at last seen the substance, and an
exact knowledge of its form renders it absolutely necessary most
materially to modify the mode of illumination.

I will state at once—and I hope to prove to the Society, as I
have proved to others, the truth of what I affirm—that the outer
surfaces of the two valves of diatoms in the family NavicuLE® are
covered with rows of siliceous hemispheres, inclined at varying
angles both to each other and to the longitudinal division of the

° Monthly Mi ical
6 Transactions of the JOuTon Sulgal geok

valve. Hence, in scientific descriptions, the terms “striation and
lineation” are no longer admissible, and the books we now have in
our hands are not a mirror held up to nature, in which the members
of this family could recognize themselves, for “striz and lines”
are just as little applicable to the rows of hemispheres on the
surface of a diatom-valve as they would be to a hayfield with its
rows of haycocks.

Further, with reference to structure, a vertical section of
P. Quadratum reveals the fact that the siliceous hemispheres on
the outer surfaces have corresponding hemispheres on the inner
surfaces ; in fact, we have perfect spheres of silica set equatorially
in the siliceous tissue of the valve’ ‘That such arrangement is the
law of the structure, does not admit of doubt. The silica is the solid
material round which the carbonaceous portion of the living cell
gathers, and thus it has its counterpart in every cell of every plant
in the vegetable kingdom, for the varying solid material of the cells
of plants is as necessary as the carbonaceous material for enabling
them to perform their proper functions in the economy of vegeta-
tion. In this respect it may be said to correspond with the osseous
system in animals. As a very different arrangement of the same
solid materials is invariably found in the mineral kingdom, we
cannot but recognize the action of different laws in the formation
of the crystal and of the cell; for, if the soluble silica obeyed the
same law during its solidification in the latter case as m the former,
we should have examples of rock-crystal in the cell instead of a
siliceous cell-wall. This consideration ought to be borne in mind
when we treat of the important subject of cell-formation. Proto-
plasm alone is not to Nature’s liking. |

As I was a pupil, I may almost say a friend, of Ehrenberg, who
named for me the Xanthidia which I found in flint, I have been
for a long time unable to recognize the entire validity of the argu-
ments which exclude the Diatomacee from the animal kingdom.
But when I now see the form and arrangement of the silica on the
cell-wall of the diatom to be so exactly like its form—and its arrange-
ment in consecutive corpuscles—on the stomata of many plants
that I have examined, and so exceedingly unlike any secretion of
silica in any other kingdom than the vegetable, I find no difficulty
whatever in placing the Diatomacez among the unicellular algee.

On viewing the surface of different diatom-valves, we find a
great difference in the diameter of the hemispheres, and in their
distance from each other. We are told, popularly, and in suffi-
ciently vague language, so far as structure is concerned, that the
“ strie” range between about 30 and 100 in yeooth of an inch,
and, to adduce an example, that the strie of P. strigilis are much
closer than those of P. formoswm—a statement which gives no
idea of the fact that the diameters of their hemispheres are the

a is | Royal Microscopical Socrety. 7
same. Doubtless it would be more accurate to give the number of
the hemispheres and the measure of the space between them, or the
ratios of the diameter and the interval.

In my own microscope, with Ross’s ;:th and a double D eye-
piece, the diameter of the field of view at the distance of the stage
from the eye is 12 inches, and this space represents the magnified
image of yoloth of a inch, on a micrometer-slide ruled by Mr.
Waterhouse. The magnifying power is therefore 12,000 linear.
Using this arrangement, P. Quadratum has 40 hemispheres and
40 intervals in the diameter of the field, ¢.e. in 12 inches, which
cover ygpoth of an inch on the micrometer-slide, and as each
interval is equal to a radius of a hemisphere, the magnified diameter
of each hemisphere covers 7°jths, and the interval 7oth of an inch.
Therefore, the real diameter of the hemispheres is godaoth, and of
each interval yscoooth of an inch. The rows of hemispheres cross
each other at an angle of 60°, as in P. angulatum, and are there-
fore arranged in the order of the sides of an equilateral triangle.
Hence, under the illusion of the common methods of illumination,
which deal with shadows only, and under deep powers, the markings
of these diatoms are described and figured as hexagons, with the
sides and centre light and dark, or vice versa, and PHoToGRAPHY
stands by as an attesting witness. But this illusion arises from
causing either the illuminated or the shaded portions of the hemi-
spheres to run into each other, and so to form hexagons with either
dark or light centres.

In a valuable paper by Dr. Wallich, “On the Development and
Structure of the Diatom-valve,” communicated to the Microscopical
Society in March, 1860, it is stated that “in P. formosum there
exists good evidence to prove that the interlinear spaces are occu-
pied by elevated rhomboidal papilla, which present facetted surfaces,
whereas in P. balticum, instead of rhomboidal elevations, we have
four-sided flattened pyramids, presenting, as in the former case,
four sets of lines, of which those bounding the spaces, and not
crossing them, are the predominant ones.” No one will be more
pleased than Dr. Wallich with the very different, but more truthful
representation of these valves when illuminated by the deatom-
prism which I will presently describe. In both valves we have
rows of siliceous hemispheres. Those in P. formosum are at right-
angles to each other, and meet the longitudinal division of the valve
at an angle of 45°. In one direction there are 24 hemispheres
and intervals in the 12-inch diameter of the field already de-
scribed, and in the direction at right-angles to it there are 30
diameters and intervals, so that the rows of equal hemispheres are
rather closer together in one direction than in the other. Here,
under the magnifying power of 12,000 linear, one hemisphere and
interval occupy half-an-inch, the apparent diameter of the hemi-

8 Transactions of the ee

sphere being +%;ths, and of the interval 32;ths of an inch; this, of
course, makes the real diameter of the hemisphere zotooth of an
inch, and therefore, with strigilis, among the largest in the range
of valvular structure. The ‘stout costa” of Pinnularia major also
follow the law of structure, and consist of very closely-packed
spheres. When. Mr. Sheppard, of Canterbury, saw these and other
diatoms under the new illumination, he felt obliged to say that the
microscope makes a new start on the Queen’s birthday, 1869; and
a young friend of mine, under fourteen years of age, exclaimed, when
he saw the formosum, that “it looked like a plate of marbles.” This,
at all events, may be adduced as the evidence of an unprejudiced
witness to the truthfulness of my story. Plewrosigma balticum,
which we have all looked upon as presenting four-sided flattened
pyramids, as described by Dr. Wallich, follows the same law of
cell-formation as its congeners, the only modification being the crop-
ping out of a rather larger portion of the sphere above the surface
of the valve.

It is amusing now to read of ingenious modes of playing with
the illuminating rays, so that the eye, fortified by a little previous
theory, may see at will, either elevations or depressions, triangular,
quadrangular, or hexagonal dots, with rhomboids, pyramids, or
spheres. But Truth is not so many-faced as this, and it 1s, there-
fore, very satisfactory to find at the conclusion of Dr. Wallich’s
paper in the Transactions, that the editors have added an important
note, which more than justifies my confidence in the accuracy of
my descriptions. It is as follows:—“In the discussion which fol-
lowed the reading of Dr. Wallich’s paper, Mr. Wenham stated that,
with an object-glass of his own construction, having a focal distance
of about ;'oth of an inch and a large aperture, he had ascertained,
beyond doubt, that in Plewrosigma angulatum, and some others,
the valves are composed wholly of spherical particles of silex,
possessing high refractive properties. And he showed how all the
various optical appearances in the valves of the Diatomacez might
be reconciled with the supposition that their structure was uni-
versally the same.” Mr. Wenham will be glad to learn that, while
the true valvular structure was revealed to him by the #oth of an
inch, a power which few hands besides his own can make, and few
observers can ever hope to possess, the diatom-prism, as an edu-
cational adjunct, will enable all observers to see the exquisite
structure of the coarser valves, for even a 3rds of an inch by Wray,
with the D and double D eye-piece, shows “the plate of marbles”
on P. formosum with abundant light and perfect achromatism.

It is needless to observe that deeper powers are required when
attacking a valve like N. rhomboides. Here the 3,th 1s used, and
I am sure that the exquisite beauty of this valve will be a treat to
critical eyes. The acknowledged difficulty of resolving it arises

Monthly Mi ical , , ,
fonthly, Microscopical) Royal Microscopical Society. 9

from the extreme closeness of the very minute hemispheres in the
longitudinal rows. Round the valve, and forming an elegant
border, are three rows of beads or hemispheres gradually decreasing
in size—then, on the semi-diameter of the valve through the centre,
14 rows of much smaller beads, numbering at least 80 in ,3,,th of
an inch—and then the two “ median lines,” which consist of hemi-
spheres as large as those in the outer row of the border. In the
centre of the valve the boss or wmbilicus pushes out the adjacent
beads of the median rows into an oval form. Powell’s immersion
lens would bear with admirable effect upon this exquisite object,
and bring out the wondrous structure which, without the aid of the
microscope, must have remained among the invisible things of Him
who created all things. This lens would no doubt show also an
exactly similar structure on the still more difficult valve Amphi-
pleura acus, the shadows of the beads being already seen as appa-
rent lines.

Such and so satisfactory is the work of the diatom-prism, which
has made the microscope, old observer as I am, quite a new instru-
ment to me. This is evident from the curious coincidence of my
having given such a different description of rhombozdes at the last
meeting of the Society. In then describing the markings as brought
out by a supposed improvement of the double hemispherical con-
denser, I used the language of the craft, and spoke of “dots as
black as jet;” but this mere silhouette representation of rhomboides,
an unnatural distortion of light and shade, I never wish to see again.

A single sentence will be sufficient to describe the diatom-prism
illumination. I place an equilateral prism below the stage of the
microscope, and the light, either of the sun or of a lamp, after
being totally reflected, is made to fall obliquely on the valve to be
examined. The light of a lamp is condensed in parallel rays by
means of a bull’s-eye lens. This is all. But why never used! Is
it possible that, without making the trial, a supposed deficiency of
the power of a few parallel rays could prove a bar to the experi-
ment? Yetit would almost seem as if such were the case, since
Newton, Chevalier, Amici, Brewster, and Abraham have suggested
different modes of obtaining condensed and convergent reflected
light, and their prisms have frequently formed adjuncts for micro-
scopical examination. But, be this as it may, the fact remains that
we are still without any authoritative recommendation to adopt the
method I have described. Its advantages, however, are great and
obvious. I have no longer two suns in my firmament, shining at
right-angles to each other, but one source of proper light properly
placed ; and therefore, instead of the false appearance of lines and
striz, rectilineal and oblique under low powers, and of hexagons
and other fancies, under high powers. I see what really does exist,
wiz. a series of beautiful hemispheres placed in their due order on

10 _ Transactions of the eee eo

the siliceous tissue of the valve. The kettledrum with its double
pencil of light is therefore, guoad hoc, a thing of the past. If the
hemisphere on the stage were really the size which our powers
make it, nearly half an inch in diameter, it would be seen by
unassisted vision, and we should smile at a supposed necessity of
forming its shadow by two sources of light, just as an artist would
smile if he were advised to have two windows in his studio at right-
angles to each other, for the more artistic illumination of his sitter.
The moon, as shown by the sun’s illumination, is a fair illustration
of diatom-illumination. Light, virtually parallel, falling obliquely
on one side only of its mountains and craters, produces natural light
and shade. Any other arrangement would fail, and for this reason
right-angled apertures either with the kettledrum or the prism lead
to illusions. The kettledrum, however, with one aperture properly
placed, is still a serviceable condenser, and brings out the hemi-
spheres remarkably well. Still, refracted light has not the power
and purity of reflected light ; and converging rays, whether reflected
from a convex prism or refracted through a lens, must yield the
palm to parallel ight, which is obtained by Newton’s plane prism
as from the sun. The truth of this remark will be obvious if we
place the smaller hemisphere of the kettledrum at right angles to
its present position, and use it for obtaining condensed, refiected, and
convergent rays from its flat surface, as proposed by Brewster. In
this case, the object, being in a cone of converging rays, is virtually
under the influence of more than one source of light, and its cha-
racter is lost amid the intense illumination. It would be easy, by
means of a double concave lens placed within the focus of the con-
verging cone, to produce an intense beam of parallel light without
any assistance from the bull’s-eye lens, and this might enable us to
detect more accurately the structure of such unapproachable fine-
ness as obtains in Aphipleura pellucida. ‘The direct light of the
sun, when reflected by the plane prism, would thus be represented
by a very close approximation.

In the mechanical adjustment of the prism to the sub-stage, I
would suggest a cradle above a ball-and-socket joint, as prisms are
often mounted, with the addition of a jointed arm, as used for the
extension of the mirror of our microscopes sideways, and, if neces-
sary, a clamping-screw to keep the prism in position. At present,
I fix the prism on the sub-stage with an india-rubber band. All
that is required 1s the power of turning the prism on its axis, and
also of placing it over any diameter or any chord of the sub-stage.
In the latter position, the prism lying over a chord from 30° east
of the vertex of the stage to 80° west of south, and its face slightly
inclined to the upper stage, very effective obliquity is obtained.
The lamp, of course, stands to the west. We must rotate the
valve by the circular motion of the upper stage, till the hemi-

Monthly Microscopical , y ata;
Hoty eros | Royal Microscopical Society. i

spheres are not obscured by the parallel lines of their own shadows.
When they reach their proper place they seem to start into exist-
ence, and the degree of elevation is conferred per saltwm. By this
perfect command over its movements, the “diatom-prism” (thus
named from its first application) will meet every requirement for
oblique, direct, and dark-ground illumination, while its simplicity and
independence of harness, in the shape of diaphragms or stops, is a
chief characteristic. The light being nearly parallel, the prism may
be moved, by the rackwork adjustment of the sub-stage, to a consi-
derable distance below the object without materially weakening the
illumination—and the slight diminution of light thus obtained is
advantageous when using low powers.

It is impossible to avoid noticing the remarkable stereoscopic
effect of this parallel reflected light. On a Barbadoes slide, for
instance, the objects are seen under an inch power and on a dark
ground in very striking relief; and the same effect is remarkably
visible when viewing the proboscis of the blow-fly on a light ground.
The peculiar character of muscular fibre is also well displayed, new
beauty is seen in the Podura scale, and infusoria and portions of
insects may be examined with additional interest.

It seems to be owing to this stereoscopic effect of parallel light
and natural shadows, that the hemispheres of diatom-valves are seen
beyond all doubt as elevations. We seem to be looking at an
opaque body illuminated from above, and the appearance in the
microscope is exactly similar to a model, made to scale, in plaster of
Paris. On the other hand, when we have anything approaching to
depressions, as in the markings of Triceratiwm and Isthmia, these
depressions are, as it were, palpably felt. The hexagonal markings
in Triceratiwm are of special interest. At every angle of the
hexagon there is a hemisphere of larger size, and smaller hemi-
spheres, in contact with each other, form the sides, so that it is
questionable whether the depression is deeper than the radius of
the hemispheres themselves. A similar inquiry also presents itself
when viewing the irregular though somewhat circular markings
formed by an arrangement of small hemispheres on the surface of
Isthinia.

I felt unwilling that the present session should close without
giving some account of my observations to those who have more
leisure than myself for pursuing these interesting researches. ‘That
the hemispheres which Mr. Wenham speaks of generally, and Mr.
Hogg figures in the case of P. formosum, are such as I have
described is, I hope, satisfactorily proved. There they are. I can
number them, I can weigh them, I can measure them—and number,
measure, and weight may be justly represented as the three rect-
angular co-ordinates of all accurate knowledge of matter.

12 On the Recent Investigations into [Mm Way eeecal

III.— Observations on the Recent Investigations into the Supposed
Cholera Fungus. By the Rev. M. J. Berxeney, M.A., F.LS.

Tue observations which were recently published by Dr. Hallier on
the supposed origin of Cholera from Parasitic Fungi, were put forth
with such confidence, and with such intimate acquaintance, as it
seemed, with lower cryptogamic forms, that they excited far more
interest in this country than they were entitled to, and, in conse-
quence, were lauded in our journals as strictly logical, either at
second-hand, or from a very imperfect acquaintance with the objects
in question, insomuch that it was deemed imperative on the part
of the medical officers of the Privy Council to submit the matter to
a complete investigation.

Two of the most promising candidates for employment in the
British and Indian armies were therefore selected to examine the
subject accurately, and to this end they were first put in connec-
tion with the best authorities in this country and on the Continent,
including Dr. Hallier himself, previous to setting out for India,
where they are now carrying on their investigations. Three re-
ports on the subject were given in the ‘ Lancet’ in the early part
of the present year, which in a short compass comprise the results
of their labours up to their departure for India. |

To a person well versed in fungi, Dr. Hallier’s observations
appeared too vague and undecided to inspire much confidence, and
the more so as it was clear that he had very loose notions as to the
real characters of genera. His leading point, that he had succeeded
by a series of changes in producing Urocystis occulta from cholera
dejections—a fungus which might possibly occur in the rice plant
—was at once invalidated by the fact that what he figures as that
species was totally different from the plant of Wallroth, by whom
it was first described as growing on rye, a fact which was easily
ascertained, as good specimens of the fungus in question were in
the hands of fungologists as published by Rabenhorst. It became,
however, matter of interest to ascertain what fungi really grow
upon the rice plant; and accordingly pains have been taken by
Mr. Thwaites, the acute Director of the Botanical Garden at Pera-
dentya in Ceylon, than whom few have a more intimate acquaint-
ance with cryptogamic plants, to acquire every possible information
both in India and Ceylon. All his inquiries, however, have failed
to detect a single fungus on the rice plant, even distantly allied to
the Urocystis (Polycystis Auct.): indeed the only fungus which
has been detected is a little species of Cladosporium, differing from
the universally diffused Cladosporium herbarum, and which, like
that, is clearly an aftergrowth, and not a true parasite. Amongst

Monthly Microscopical | the Supposed Cholera Fungus. 13

some 7000 numbers of fungi from North and South Carolina not a
single one occurs on rice. is ic)

His argument, moreover, as to the eastern origin of Tilletia, as
though it were confined to wheat, was entirely overthrown by the
fact that it occurs on decidedly European grasses, from which it
might as easily be derived to wheat, as from wheat to these grasses,
and that a distinct species occurs on wheat in the United States,
which is not known in any other country.

His experiments, moreover, were conducted in such a way as to
make it almost impossible to say whether any particular form was
derived from some especial spore, without which it is clearly pre-
mature to arrive at any plausible conclusion.

There is, indeed, no doubt that from the spores of a particular
fungus, under different circumstances very different forms of fructi-
fication may occur, a fact with which every mycologist is familiar ;
but these forms are in general mere modifications, as was shown in
the ‘Journal of the Linnean Society’ in an article on the Fungus-
foot of India; while some, as the so-called Torulee, have no title to
the name of true fructification at all, but are rather analogous to
gemme, as is the case with the so-called yeast plant. It is also
quite true that in the same species we may have two or more dis-
tinct forms of fructification; and few matters are more interesting
than to trace out the connection of many so-called genera with the
more normal form, as has been done so successfully by the Messrs.
Tulasne; but this is a totally different thing from the transfor-
mation of one genus into another. Indeed there is not a single
ease indicated by Dr. Hallier which is entitled to the same praise
as the numerous cases demonstrated by those authors. An atten-
tive perusal of the report of what Drs. Cunningham and Lewis saw
at De Bary’s, and the instructions derived from him, as well as that
of their conference with Dr. Hallier, will be quite sufficient to
make us receive Dr. Hallier’s views with much less attention than
they have attracted in certain quarters.

It is quite possible to follow the development of a single spore,
as is indicated in the article Yeast in the ‘ Encyclopedia of Agri-
culture,* though this has been called in question by De Bary. It
is true that if certain minute bodies be insolated from yeast, we
may not always be certain that they are not derived from some
quarter extraneous to the yeast itself; but if we get them to fruc-
tify, we shall at least have some certain information as to the
different phases which have been assumed by a particular fungus,
and it will be found that the medium in which the fructification
takes place will make an immense difference. If we repeatedly

* The same method was pursued to ascertain the real nature of the little Scle-
rotium which is so common in onions, as indicated in an article in the ‘ Journal of
the Royal Horticultural Society of London.’

14 ‘Supposed Cholera Fungus. —— [Monthly Microscopical

obtain the same result, and if this corresponds with what is exhi-
bited by rougher experiments, we shall be pretty certain that we
have indeed arrived at the true nature of the yeast plant.

What is really wanted at present is to trace accurately the
development of those obscure bodies which are the first signs of
vegetable life in infusions or in substances in an early stage of decom-
position. No one seems to know exactly what the little variously-
coloured gelatinous bodies are which occur in paste and other moist
vegetable substances, and amongst them the so-called blood-rain ;
and the same may be said of what are variously called Bacteria,
Vibrios, or Leptothrix, and which come in close succession to the
monads. The investigation is certainly one of great, but perhaps
not insurmountable difficulty, and might be carried on in closed
cells containing a drop of some suitable fluid surrounded with air.
When examined en masse, it is almost impossible to say with any
certainty that one form is derived from the other, however probable
it may be that this is actually the case.

Our young commissioners were very properly placed in com-
munication with Professor Huxley, who has paid especial attention
to this interesting matter. When we had an opportunity of exa-
mining his preparations, it must be confessed, under very unfavour-
able circumstances as regards illumination, we saw sufficient to hope
that he would continue his investigations, and we think that he has
exercised a very wise discretion in not publishing his observations
too hastily.* We have long thought that the subject is one of the
highest importance as regards many sanitary questions, and, if
thoroughly worked out without the slightest tendency to draw con-
clusions in any especial direction, we feel confident that much good
would be accomplished.

The preparations which were given by Dr. Hallier as to the
connection of fungi with scarlet fever, &c., which we had an oppor-
tunity of examining, proved absolutely nothing, as far as we could
see; and as regards the emanation of fungous spores from drains
or other localities containing putrefying matter, which we are not
inclined for a moment to deny, we should require some tangible
proof before we arrive at the conclusion that they have anything to
do with disease.

It would be mere folly to blind the eyes to the experiments of
Pouchet, Child, Bennett, and others, as to what is called the Atmo-
spheric Germ theory; but, whatever may be the origin of the
minute bodies in question, whether from pre-existent spores or
the fortuitous concourse of chemical and other energetic forces, it is

* The cell-forms observed by Rainey and others in various viscous substances
prove but very little, unless it dould be shown that they were real cells with a
wall composed of cellulose, and nitrogenous contents. That cells may originate in

organizable matter is clear from the mode in which spores are formed in the asci
of ascigerous fungi.

Monthly Microscopical] Correlation of Microscopic Physiology. 15

a matter of immense importance to ascertain whether they have any
real connection with disease, and it is at once obvious that the
question as to their origin becomes eminently essential. If these
bodies can arise from accidental momenta, and if at the same time
they have any connection with hospital gangrene, erysipelas, or con-
tagious fevers, we need not be surprised at the occasional insolated
origin of such diseases, from whence they may spread in definite
directions.* At present there is no proof whatever that different
fevers owe their origin to different parasitic fungi, or that especial
forms of the same common species appear constantly in the several
forms of fever, a circumstance for which there is better evidence
perhaps as regards certain skin diseases. It is, however, unfor-
tunate that the writers on these subjects are seldom persons who
are well acquainted with fungi. We may, as an instance, adduce
the assertion in Dr. Bennett’s important lecture before the College
of Surgeons of Edinburgh, 17th January, 1868, that the genus
Aspergillus is characterized by “capsules containing numerous
globular seeds,” a character which, to a certain extent, would apply
to Mucor, the genus Aspergillus however bearing like Penicillium
necklaces of spores, but seated on an ovate or globular base of rather
complicated structure.t

We shall wait with much interest for the complete report from
India, which, from the intelligence of the young men engaged in
the inquiry, will, we are sure, justify the selection which has been
made by the Privy Council.

IV.—On the Correlation of Microscopic Physiology and Micro-
scopic Physics. By Joux Brownine, F.R.A.S.

At a late meeting of the Royal Microscopical Society I listened
with great interest to a paper kindly written for the Society by
Dr. Beale, on Protoplasm.

On the physiological details in that paper I shall not attempt

* It appears from experiments made by Mr. Hoffman at the Marine Infirmary
at Margate, that diseases such as Pyemia, which occasionally spread from bed to
bed, may be insolated by the use of iodine placed under the bed and bedclothes.

+ The assertion in the same lecture, p. 24, that Mr. Busk found spores of
Uredo segetum in choleraic dejections is incorrect. What was really found was
spores of the common Bunt (Tilletia caries). The spores of the Uredo, or rather
Ustilago, are all blown away by the wind long before the seed is ripe, and never
accompany the grain into the miller’s hopper.

I may take this opportunity of calling attention to the fact, which is not gene-
rally recognized, that Homer was perfectly aware of the origin of the larve which
appear in putrefying carcasses. See ‘ Iliad,’ xix., vy. 23, where he says that flies
generate the worms.

16 Correlation of Microscopic Physiology [Monthly Microscopical

to offer an opimion. But in the paper, and more particularly in the.
discussion which followed the reading of the paper, Dr. Beale made
requent references to various branches of physics.

The tendency of those remarks, if I understood Dr. Beale cor-
rectly, was to deny that any close relationship exists between
microscopic physiology and microscopic physics. It seems to me
desirable to state some of the leading facts that can be adduced in
proof of such a relationship.

Before proceeding to the parallels I wish to draw between
microscopic physiology and microscopic physics, I must refer, briefly,
to a point which was raised in the discussion that took place after
Dr. Beale’s paper was read, as to the instantaneous death of cells.
Dr. Beale evidently supported this hypothesis.

The word instantaneous is often used with respect to motions
which take an appreciable amount of time. By the aid of the
electric chronograph, astronomers now register the passage of time
to hundredths of a second.

The velocity of light is nearly 200,000 miles a second. Its
passage across a single cell would require, then, a certain amount
of time to complete it. Reasoning from analogy, we are forced
to conclude that whenever a change occurs in any matter, tome will
be required for the change to be completed.

But Dr. Beale laid the greatest stress on the motion of mucus
as necessitating the assumption of the action of a vital force. It
seems to me that a parallel case of motion can be found in molecular
physics.

When a soft iron rod is powerfully magnetized by means of a
voltaic battery, it expands. On the connection with the battery
being broken, it again contracts. /

This action, by a proper arrangement of the voltaic battery, can
be easily made automatic, and would then go on until the power of
the electricity was exhausted. During the whole time, the iron bar
would give out a distinctly audible sound at every expansion and
contraction.

Faraday tried this experiment, and failed to detect the expan-
sion. We owe the knowledge of the fact to Professor Tyndall, who
made the discovery by using more delicate apparatus. In all pro-
bability Faraday would have succeeded if he had used a powerful
microscope, furnished with a micrometer to measure the length of
the bar. I think it is much to be regretted that physicists do not
have more frequent recourse to the microscope. Mr. Sorby has
made many discoveries by applying the microscope in a most inge-
nious manner to the investigation of the structures of iron and
steel, iron ores, and meteorites.

Of another kind of motion, analogous to ciliary motion, my
friend, Mr. Chandler Roberts, has kindly shown an example ; in-

ae ie and Microscopic Physics. | gud
deed, he contrived one form of this experiment for the purpose of
illustrating my remarks in this paper.

It consists of a strip of the metal palladium in water. When
contact is made with a small galvanic battery these strips of metal
will roll themselves up into spiral coils. Some will vibrate, some will
actually move forward with a motion closely resembling that of a
common earth-worm. On the connection with the poles of the
battery being reversed, all the movements will take place in a
contrary direction. These strange movements are caused by the
metallic palladium absorbing the hydrogen which would otherwise
be given off by the decomposition of the water. This hydrogen is
expelled when the poles of the battery are reversed, or it unites with
the oxygen which is now produced, and together they form water.

This arrangement can also be made automatic. Yet this palla-
dium will in time lose the property of expanding and contracting
on being connected with the battery, because its molecules have
undergone a great change in their arrangement, not, I presume,
because the palladium has lost its vetal force.

Fortunately we are not in doubt as to what change occurs, for
Mr. Roberts, after repeatedly charging a palladium wire with 600
times its own volume of hydrogen, and then expelling it, examined
the wire with a microscope and found it torn and rent asunder.

This motion is due to physical causes over which we have com-
plete control; but, apart from such cases as this, we have good
reasons for believing that all forces are modes of motion.

If we take a powerful galvanic battery, we find the chemical
action changed into, or producing electricity. Cause this electricity
to pass through a wire and the wire will become hot; let it pass
through a smaller wire, that is, terpose a greater resistance to its
passage, and the wire will become white hot and give out light.
By allowing the heat to fall on a thermo-pile, we can again convert
it into electricity.

Light has long been considered as due to the rapid undulations
of ether. Heat and electricity Prof. Tyndall and Mr. Brooke have
taught us to regard as modes of motion. On this hypothesis the
correlation of the physical forces becomes an exceedingly simple
matter to understand. ;

When we throw a spectrum on a screen, if we use a delicate
thermometer, we find that the greatest heat exists beyond the
visible rays of the red end of the spectrum. Dr. Tyndall has shown
these heat rays may be separated from the light rays, and various
substances may be set on fire by such rays brought to a focus by a
lens, the substances becoming heated and lighted without contact
with other matter in the dark, the effect being a result of envisible
motion. ‘This fact would probably be disposed of as ¢nconceivable
by anyone unacquainted with physics. |

VOL. IL. C

18 Correlation of Mieroscopie Physiology _ [ Monthly, Microscopical

There are probably some grounds for believing that the particles
or molecules in magnets are always in motion. Mr. Wenham once
told me that he had seen a cavity in a crystal partially filled with
a fluid, and for several years this fluid had been unceasingly in
acne although completely shut off from the surrounding atmo-
sphere.

Motion, then, is not peculiar to life, and we shall be brought at
last to the single distinction—reproduction.

The difficulty here would be insuperable if we were compelled
to accept the hypothesis that life is transmitted from one organism
to another. But this hypothesis is no longer generally accepted.
Prof. Owen, who has been until recently opposed to such views, has
at length accepted the hypothesis of spontaneous generation.

An article in ‘Scientific Opinion, April 28, thus tersely states
the case in favour of this hypothesis:—“If when we expose an
organic infusion to the air it soon becomes peopled by myriads of
animal and vegetable forms, either these have been formed sponta-
neously, or their ova have been carried to the infusion through the
atmosphere. Now the latter alternative involves an hypothesis
difficult to prove, and as yet far enough from demonstration. It
insists on the supposition that the air is charged with the germs of
the animals and plants. But is this the case? There seems to be
but very little testimony in its favour. M. Pasteur asserts that
it is so. But Bennett, Pouchet, and several others skilled in the
use of the microscope, have failed absolutely to detect these ubi-
quitous germs. Whence, then, are they derived, if not from the
decomposing organic matter? Many of those who are still sceptical
as to heterogeny, admit that they have watched the conversion of
bacteria into fungoid growths; and some have even alleged that they
have witnessed the conversion of bacteria into infusoria. Surely
these are as difficult statements to digest as the theory of sponta-
neous generation.”

Chemists were wont until very recently to divide all substances
into organic and inorganic. Even then an account had to be given
of the compounds in salts formed by the union of metals with
organic acids. Now in the latest works we find a list of substances
called organo-metallic bodies, in which the metals zinc, tin, cad-
mium, mercury, magnesium, aluminium, and glucinum are directly
combined with organic radicles. In these compounds zine may be
found as a constituent of a volatile ether.

There is no boundary line then between organic and inorganic
substances, neither is there any boundary line between plants and
animals, Diatomacez being placed by some observers in the animal,
and by others in the vegetable kingdom. Reasoning by analogy,
I believe that we shall before long find it an equally difficult task
to draw a distinction between the lowest forms of living matter and

etic is and Microscopic Physics. y 19

dead matter. The hypothesis that every living thing comes from
an egg has given way to another—every living thing comes from
a cell.* Probably we shall, in due time, find under what conditions
cells are first formed, and thus the lower forms of life created.

But a few years since the question “ What is heat?” would
have puzzled the greatest philosopher ; now, thanks to Dr. Tyndall’s
valuable work, hundreds of school-boys could answer it.

The problem of the conditions of cell-life is peculiarly a problem
for microscopists. Surely much may be hoped for, from their
known perseverance and ingenuity, notwithstanding the apparent
insolubility of the problem.

It has been stated that crystals never form curved lines. This
assertion is not strictly true. ,

A point of great importance in this connection is that Mr.
Rainey has found that when a solution of a lime-salt in gum-
arabic is slowly decomposed, carbonate of lime is deposited in
spheroidal concretions. Sometimes two of these will unite and
form a dumb-bell ; occasionally a number will unite in the form of
a mulberry. According to Dr. Carpenter, similar concretionary
spheroids are common in the urine of the horse,.in the auditory sacs
of fishes, in the skin of the shrimp, and other imperfectly calcified
shells of crustacea, as well as in certain imperfect layers in the
shells of mollusca.

Again, it has been stated that carbonate of lime is not deposited
in animal substances in the crystalline form. Dr. Carpenter says
that the external layer of an ordinary egg-shell consists of a series
of polygonal plates resembling a tesselated pavement. |

Professor Williamson says that there can be no doubt that the
calcareous deposit in the scales of fishes is formed upon the same

lan.

Want of space alone prevents me from adding other examples ;
but from the instances I have given we may see that the presence
of organic matter is often sufficient to prevent the deposition of
lime in a crystalline form, and to cause it to assume a circular
form, either in or out of a living organism ; while in the second case
we find that vitality does not prevent the deposit of lime in the
crystalline form. :

In a very suggestive speech Mr. Slack referred to the triumphs
of modern chemistry—the building up of highly organized sub-
stances—synthesis. Dr. Beale objected that no parallel could be
fairly drawn here, because the method by which the highly
organized substances are produced naturally is go exceedingly

* Hven this proposition is extremely questionable. It is certainly unfounded
if the current definition of the word “cell” be accepted. Absolutely it resolves
itself into this: that living things proceed from a substance which may —followin
Prof, Huxley—he very fairly though generally styled Protoplasm.—Ep. M. M. J.

GZ

20 Correlation of Microscopie Physiology {Monthly Microscopical

simple. Is this the case?* Do we not rather find that highly
organized substances are never produced except as the result of
two or three processes? Man cannot assimilate the elements either
of the earth or air to form living matter. They must first be assimi-
lated by the plant. The plant nourishes the animal. The animal
serves as food for a higher grade of animals, or for man.

According to good authorities, osmose will take place against
a pressure of several atmospheres. It should be borne in mind
that this passage of liquids against pressure takes place through
plaster of Paris, carbonate of lime, and even earthenware, as well
as through animal and vegetable membranes.

Referring to this point I find the following important passage i in.
Watt's ‘ Dictionary of Chemistry ’:—

“In osmose there is a remarkably direct substitution of one of
the great forces of nature for another foree—the conversion,
namely, of chemical action into mechanical power.}

“Viewed in this light, the osmotic injection of fluids may,
perhaps, supply the deficient lmk which intervenes between
chemical decomposition and muscular movement. The ascent of
the sap in plants appears to depend upon a similar conversion
of chemical, or, at least, molecular action into mechanical force.
The juices of plants are constantly permeating the coatings of the
superficial vessels in the leaves and other organs; and as these
evaporate into the air, a fresh portion of the liquid is absorbed by
the membrane, and evaporates; and thus a regular upward current
is established, by which the sap is transferred from the roots to the
highest parts of the tree.

“ In a similar manner, the evaporation constantly taking place
from the skin and lungs of animals, causes a. continuous flow of the
animal juices from the interior towards the surface.”

I think we have seen that we do not need to assume the action
of a special vital force to carry on these all-important changes of
secretion and excretion in plants and animals.

Physiologists who agree with Dr. Beale always point to the
fact that oxygen attacks some tissues of the living body and spares
others; but a parallel to this can be found in the behaviour of the
metal-plates i in a voltaic cell, consisting of a plate of zinc and plate
of copper in dilute acid. So long as they are not united, no action
takes place. The moment, however, that a connection is established
between them, the zinc rapidly decomposes the water, with the
evolution of hydrogen gas.

The nervous system may possess a controlling power which can
suspend the action of the respired oxygen, or permit it to take effect.

* The answer to. the question is, that we really know nothing about it.—

Ep. M. M. J.
+ Vol. v., 721.

eon Liss. and Microscopic Physics. ‘21
We are continually asked why we object to the term vital force ?
For the same reason that in previous ages other advanced thinkers
have objected to various phenomena of nature being explained,
by the supposition of the action of “phlogiston,” and of the great
principle so long firmly believed in, that “ nature abhors a vacwum.”
In fact, our point lies in this simple fact—that men are apt
to believe that they have got ¢deas, whereas they have only got
words. #

Space forbids me to enlarge on this tendency, but I must give
one illustration.

There are many substances known to chemists, both simple and
compound, which will not unite when brought together, unless a
third substance be present. Yet after their union no alteration can
be detected in this third substance, which has apparently effected
the change. This action has been named a catalytic action, and
two distinguished foreign chemists have supposed that there must
be a special catalytic force. Some of our leading English chemists
have preferred to call this action simply contact action. Doubtless,
experiments will at last enable us to understand what action
ensues when these contacts occur, and thus furnish us with an ex-
planation instead of a name.

The only condition on which life can be sustained is that of
unceasing death. The death of the cells is indispensable to the life
of the beng. How can we escape the conclusion, that the life of
the individual is the sum total of the life contained in the matter
of which the cells were composed? When we evolve heat by the
combustion of coal, we acknowledge that we simply reproduce
the solar heat that had been absorbed by the coal-plants. If we
admit the hypothesis of spontaneous generation, we have to admit
that the power of forming cells must have existed in the elements
of which they are composed, and that only favourable conditions
were required to enable the first cell to be produced.

“Dr. Beale objects that living and non-living protoplasm
cannot be regarded as the same substance, and therefore ought not
to be called by the same name.” *

We speak of bone and flesh, hair and skin and nails, whether
alive or dead; why should we be called on to give two names to
protoplasm ?

One of the most curious and interesting, I have heard it called
the most inexplicable, of all the phenomena of life, is that of sus-
pended animation, let us say, by drowning, when by the application
of electricity, heat, or artificial respiration, the life is apparently
restored.

* Dr. Beale has never given any satisfactory reason for this division of the

materials of the tissues into living and dead. The argument from the use of
carmine is, in our opinion, simply a Petitio principii— Ep. M. M. J.

0 Monthly Micros jeal
22 Notes on Hydatina Senta. — [Monthly Microseopieat

Yet this phenomena may be imitated with a common pendulum
clock which has been stopped, and which can be set going by
blowing the pendulum, and will appear self-sustaining afterwards.

Of course this does not occasion any surprise, because we know
that the power of gravity serves to keep the clock in motion.

In time, by diligent research, the greater mystery will, doubt-
less, be revealed to us.

It will be worse than useless, nay, it will, as tending to retard
inquiry, be mischievous to set down all the complex actions going
on in organized beings as the result of a special vital force, until we:
are certain that it is hopeless to expect any further addition to our
knowledge. Can we ever be certain of this? What do we know
of the power of electrical force, or the extent of its action ?

We know that it will unite the inert elements of our atmo-
sphere, and cause them to form the corrosive liquid nitric acid.
We know, also, that it will rend asunder sodium and oxygen. It
will cause an iron rod to expand, a muscle to contract. It is most
improbable that we know the full extent of its action in the animal
economy.

A distinguished French philosopher, the Abbé Hauy, writes :—
“Those specious causes and imaginary powers to which, in the
Middle Ages, all natural phenomena, even those of an astronomical
kind, were referred, but which, through the genius of Newton and
Laplace, have been banished from the celestial spaces, have taken
their last refuge in the recesses of organized beings, and from these
retreats positive philosophy is preparing to expel them.”

Why are researches in this direction opposed, or regarded with
prejudice? As a result of them we may hope to arrive at the truth ;
and surely, as an eloquent French preacher has said, the nearer we
are to truth, the nearer we are to God.

V.—Notes on Hydatina Senta. By C. T. Hupsoy, LL.D.
PuatTe XIX.

THERE is so little known of the life-history of the Rotifers, and so
many points of their structure remain unexplained, that it seems at
first quite superfluous to notice any of their diseases; and yet I
am tempted to record the following facts, as they may prove in-
teresting to those who are engaged in the same study as myself.
In the beginning of February I found Hydatina Senta in
tolerable abundance at Bedminster, in a large rain-puddle into
which manure-water trickled. On returning a few days afterwards
for some more specimens, I fished all round the puddle, and at
different depths, in vain ; butin a hoof-print close to the puddle, and

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ee
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Auctor de|. Tuffen West sc.

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thiy Mi ‘opical y ;
*Journsl, July 1, 1969. Notes on Hydatina Senta. 23

filled from it, there were plenty of Hydatina, and this small
reservoir continued to supply me with fresh specimens for nearly
a fortnight, while they were never to be found in the puddle. At
the end of the fortnight all the rotifers disappeared, although, so far
as I could see, there was no change of any of the circumstances
under which they had previously thriven. ‘The only thing which
had altered was the temperature, which had suddenly fallen, and
perhaps this was a fatal change to rotifers in so small a quantity of
water as that contained in a hoof-print ; but why they should have
originally deserted the puddle for such a preposterous residence I
cannot imagine.

Almost all the specimens I obtained from Bedminster contained
internal parasites ; while a few had what appeared to be the mycelium
of a fungus growing in the space between the cuticle and the internal
organs. The white network of the mycelium stretched into every
portion of this space, and surrounded (though loosely) the stomach,
mastax, ovary, &c. &c.; frequently crossing the larger muscles and
bending them out of their proper directions; but the creature did
not seem to be distressed in any way by this parasitic growth, and
its motions were quite as active as those of a healthy Hydatina.
Fig. 1 represents Hydatina held down by a compressorium, and
shows the mycelium which I have drawn as accurately as the
intricate nature of the meshes would permit; and at Fig. 2 is
shown a small portion of the mycelium more highly magnified.

I isolated one or two of the rotifers thus affected, in the hope
of seeing a further development of the fungus; but I was not suc-
cessful, for they all soon died.

The internal parasites of Hydatina I have often seen. They
were figured first by Leydig; and a translation of his paper, in
which there is a notice of them, was given in the ‘ Annals of Natural
History’ for 1857. They are of a narrow oval form, and average
séoth of an inch in length; and when in Hydatina’s stomach are
in incessant and vigorous motion, jerking the contents of their bodies
forwards and backwards, so as to make a cylindrical mass travel
rapidly to and fro in the most curious manner.

Figs. 3, 4, and 5 are different views of the same animal when
in unrestrained motion. While passing through these various
shapes, it pushes its way quickly up and down Hydatina’s stomach,
usually taking up its position close to the upper extremity, and a
little to the side of the opening into the cesophagus. Even when
the anterior portion of the parasite is right against the walls of the
stomach, the cylindrical wave never ceases to travel up and down
its body, and occasionally the motion is complicated by a spiral
movement being added to the other.

It not unfrequently happens that when the parasites in their
travels reach the lower stomach they are suddenly expelled, and for

24 Notes on Hydatina Senta. roueea ee ot

a short time they will swim straight on as vigorously as ever; but
they soon begin to slacken their pace, the characteristic cylinder
can scarcely traverse the body, and after a few spiral contortions
they lie motionless in the shapeless attitudes which Leydig has
drawn in his four upper figures.

On one occasion two of the parasites so expelled started together
to cross the field of view, which they did in excellent style, never
swerving from a straight line, and passing out of the field, as they
entered it, neck and neck. I timed the race, and found that they
swam through one-tenth of an inch, or about thirty times their own
length, in a minute.

Fig. 6 represents the animal flattened by the compressorium.
There is a red spot (a) near the anterior portion of the body, and
clear transparent spaces (b, b) which frequently change their posi-
tion and form, though usually circular. The bodies (¢, ¢, c) are of
all sizes, from zoy5yth of an inch downwards. They are hollow and
brittle, and can be broken as at (d) by flattening the animal. Fig. 7
shows one more highly magnified ; it is a roughly spheroidal globe
with a half-projecting rmg forming what may be termed its equator,
and there are at the poles two funnel-shaped cavities whose narrow
extremities are turned towards the centre and each other. As these
bodies are thrown backwards and forwards by the animal, they turn
over and move freely among each other.

It is a difficult matter to make out satisfactorily the arrange-
ment of the cilia on Hydatina’s head, owing to its incessant motion.
I have repeatedly watched this rotifer while alive, by dark-ground
illumination, as well as by transmitted light, and (availing myself
of Leydig’s method of killing it) have succeeded in obtaining fre-
quent front, back, and side views of the extended cilia after the
animal was dead ; and I do not think that either Cohn’s or Leydig’s
figure fairly represents the trochal wreaths. That there are two
continuous wreaths, one on the outer and the other on the inner
edge of the disc, is obvious enough ; and those of the outer row are
curved outwards, while those of the imner are curved inwards
towards the buccal funnel ; but it is the middle row of much larger
and straighter cilia which is perplexing. Cohn makes it a suc-
cession of detached groups of straight cilia arranged like fans on
round protuberances between the inner and outer row. Leydig
has, on the whole, a much more accurate figure of the trochal disc,
but represents the middle row as “forming a continuous series.” Now
it does not appear to me that the middle row is either continuous
or all broken up into tufts. It is with considerable diffidence that
I question Cohn’s or Leydig’s statements ; but as these excellent
observers do not agree, there seems to be room for a third opinion.

There are, I think, three-main groups of radiating cilia—one
(Fig. 8, a) on a papilla placed towards the dorsal surface and in the

Monthly Microscopical) Structure of Podura Scales. 25
median line with a smaller similar group on a papilla (b) just below
it. The two other groups (¢,c) lie right and left of the large cavity
that leads to the buccal funnel, and each is the extremity of a curved
row of large cilia lying between the inner and outer small ones, and
ending with them at a point (d) on the ventral surface opposite to
the buccal funnel. Leydig places the aperture of the buccal funnel
almost in the centre of the large cavity surrounded by the inner
row ; but, asshown in Fig. 9 (which is an imaginary section of the
head), the whole cavity slopes down towards the ventral surface,
and the entrance to the buccal funnel (d) is close to it. The other
letters in the figure refer to the same parts as in Fig. 8. Fig. 10 is
a dorsal view of the top of the trochal disc.

In attempting to make out the structure of the teeth either by
crushing the animal or dissolving it in caustic potash, it frequently
happens that the parts are so thrown upon each other that a distinct
' view is impossible; but a few days ago I obtained a specimen capi-
tally placed, and was able to see that the edges of the incus are
themselves armed with fine small teeth (Fig. 11, a, a), which have
not, I believe, been previously noticed, and which no doubt com-
minute the food that has been partially torn by the larger teeth.

In Fig. 12 are shown the muscles of a specimen that has been
killed in bichromate of potash, and compressed so as to make the
muscles show their points of attachment. ‘The muscles 1 and 5
retract the head, and so do the anterior portions of 2 and 4, which
latter, in conjunction with 3, also act to draw in the foot; 6 is a
small muscular thread from the spot where the dorsal sete are
situated to the head; and 7-12 are similar small threads that
retain in their places the gastric glands, mastax, stomach, ovary,
and contractile vesicle. Of course the figure only represents the
muscles on one side of the rotifer: they all occur in pairs, and
Fig. 13 shows how curiously they terminate in the foot.

A rocket-shaped body carrying sete (Fig. 14) exists on either
side of Hydatina (Fig. 16, a), just as in Triarthra; but it varies a
little in shape from similar ones (Fig. 15) that are found at the
extremity of Synchceta Tremula.

V1I.—Some Remarks on the Structure of Diatoms and Podura
Scales. By F. H. Wenuam.

At the last meeting of the Royal Microscopical Society (June 9)
this much-vexed question was again revived, in the discussion
following the paper read by the President.

In consequence of the higher powers and more perfect definition

26 Remarks on the Structure — [Nenthly Microscopteat

of our object-glasses, made within the last fifteen years, the struc-
ture of many of the Diatoms, such as P. angulatum, Formosum,
Balticum, &c., seems to have been decided, and their nature, as
nodules of silex, generally admitted as facts, from the palpable
method of examining broken edges of the scale and detached frag-
ments.

Though the Podura may be well defined with objectives, which
fail to afford even indications of markings on these diatomaceous
tests, yet the structure of this scale is far from being satisfactorily
determined, To bring out to the best advantage the opaque-looking
spines, or “note of exclamation” markings (which ig their un-
doubted form), it is generally admitted that the direct light from
an achromatic condenser is the best mode of illumination, as it ig
also most reliable and free from error, and is the one adopted by
the constructor of object-glasses for the final examination of his
workmanship, the test marks being this recognized form. Obliquity
of illumination would blend and confuse these markings, and produce
an appearance much similar to that of spherical aberration in the
object-glass itself, and might be mistaken for such.

‘Let a strongly-marked and suitable Podura be now examined
with the highest powers, say ='5 or 3'5, using the deepest eye-piece,
and even lengthening the body by the draw-tube (and many of our
recent object-glasses will bear this admirably), the ilumination
being that of the achromatic condenser with adjustable apertures.
Under these circumstances the scale will be so enormously magnified,
that only a small portion of it will occupy the whole field of view,
supposing the adjustment for spherical aberration or thickness of
glass-cover also to be exactly corrected. Under this excessive
amplitude, each individual marking still retains its characteristic
form ; but though it is a body evidently having ‘some bulk, not the
most careful focussing can determine that it stands above the surface
of the scale. On the contrary, there is a slight and peculiar shading-
off of an apparent intervening membrane next the markings, giving
rise to the idea of a kind of rising between them, so that I have
known several that have seen the Podura under these conditions
declare that the markings are actual depressions, or dark pigment
cells.

Let us next work through this subject with the Binocular
microscope. Though it must be admitted that the application of
this to difficult tests is not very satisfactory, yet in a coarse Podura
the markings are sufficiently well defined and still retain their
characteristic form, but it utterly fails in throwing the spines up
in relief as from an underlying surface, and affords no additional
knowledge of the structure ; but at the same time, if the entire scale is
hollow or distorted, this is immediately detected by the aid of double
vision. Further, let the test be examined by some approximate
mode of opaque illumination: by this we are limited to much lower

Monthly Moreno | of Diatoms and Podura Seales. 27

powers by the difficulty of obtaining light, but under the parabolic
condenser, with a }th object-glass and a black field, this is a most
brilliant and beautiful object. ‘The so-termed spines still retain
their peculiar form and decided materiality ; and being as they are,
either somewhat opaque or coloured, they retain the light, and now
appear luminous instead of dark, as before. In all other respects
of interval, form, and position, they are the same as under trans-
mitted light, and we are equally unable to prove that they exist in
the form of projections.

We will now consider the effects of fracture or dissection. Mount
the scales from a recently-killed Podura on thin glass in the
usual way. Take a fine needle, and roll and draw it amongst them,
so as to mutilate them as much as possible, and place the thin glass
on a slide for the examination. The first thing that strikes the
observer, is the remarkable flaccidity of the scales. Comparing
great things with small, they appear as limber as pieces of wetted
paper, and roll up and crumple in a similar manner; and at the
spot where the specimens have been most bruised and broken, there
is evidently moisture deposited on the glass, showing that the mem-
branes contain fluid when the scale is attached to the living insect.
The markings on the surface of such scales as are bruised, are not
thrust sideways to any notable degree, they remain much in their
original place, and appear merely to be flattened or mashed out to
some extent, indicating a very firm attachment. Other scales that
are doubled up, or folded over, show the markings exactly semilar
on both sides, and there is nothing peculiar at the line of flexure.
If the markings were real spines, they would here stand out like
the short bristles of a piece of hide when folded together. But the
markings ply round the sharp bend so closely, that the keenest eye
cannot detect any appreciable rib or projection at the edge of the fold.

By transferring the investigation to a scale that has been
ripped open, or torn across, nothing more can be learnt. The tear
continues without interruption clean through the markings, one-
half of which will be left on one piece, and the other half on the
detached one, and no snags or projections can be seen on the clear
edges of the suture.

Not much therefore can be decided, as to the structure of this
delicate object, by dissection, as in the case of the Dzatoms, the
brittle nature of whose built-up siliceous skeletons enables them to
be broken up into the individual atoms of which they are composed.
The only proof afforded by the experiment has been, that the mark-
ings of the Podura are very strongly attached to the scales, and so
incorporated with the membranes that separation cannot be effected.
We must therefore again resort to illumination in hopes of solving
the mystery.

On March 26th, 1856, I read a paper before the Microscopical
Society, “ On a Method of Illuminating Opaque Objects under the

98 Remarks on the Structure [Monthly Microscopical

Highest Powers of the Microscope,” on the principle of “ causing
rays of light to pass through the under-side of the glass slip upon
which the object is mounted, at the proper angle for causing total
internal reflexion from the upper surface of the cover, which is
thus made to act the part of a speculum for throwing the light
down upon the underlying objects immersed in the balsam or fluid.”
The effect of this is that the objects are shown beneath an intense
sheet of light, not any of which can enter the object-glass except
that from the object itself; consequently the field is perfectly dark.
Though this is very easily managed, and in the form here repeated
costs but a few pence, yet it has attracted but little notice, and, as
far as I know, has been used by no one else but myself. Various
modes of effecting this are described in my published paper, but I
transcribe the one employed in the present question. Besides the
apparatus possessed by most microscopists, it only requires the little
truncated lens, b (shown full size), which is stuck on the slide by a
film of any highly refractive oil, such as that of cassia, or cloves :—

“Fig. 3 is another method ; a a is a glass slide—under this is
cemented with Canada bal-
sam a lens, b, nearly hemi-
spherical, with a segment
removed so as to leave the
thickness equal to about
one-third the diameter of
the sphere. ‘The flat facet
of the lens is blackened. The
radius of curvature should
be about two-tenths of an
inch: the use of the black-
ened facet is to exclude all
rays below the incident
angle of total reflexion.
This lens is intended to be used in conjunction with the parabolic
condenser, in the manner represented by the figure. The rays
from the parabola pass through the surface of the lens in a radial
direction without refraction, and proceed till they reach the upper
surface of the thin glass cover, where they are totally reflected and
converge upon the object ; the cover in this instance acts precisely
the part of a Leiberkuhn, with the advantage of more pertect
reflexion.”

As Podura scales are generally mounted on the thin glass cover,
it must not be expected that these will be illuminated as dry objects
by such means, for the total reflexion takes place entirely from the
top surface of the slide, and not a vestige of the upper objects will
be seen. But in the intense black field a few solitary scales will be
found illuminated with singular beauty and brilliancy.. These have
become detached from the cover and lie upon the under slide, and

Monthly Microscopicat) of Diatoms and Podura Scales. 29
by their close adhesion prevent the total reflexion of light at the
spot beneath, consequently it is like a hole made im a dark lantern,
and a flood of light escapes through the scale. Herein, as with the
parabolic condenser, the markings are the most intensely illumi-
nated, and appear the brightest; and under a good 75 or 25, con-
trasted with the surrounding darkness, the aspect of the Podura is
at the first glance so novel, and different to what we have been
accustomed to, that the black interspaces may be mistaken for the
markings, pointed in the reverse direction; but on looking again,
there are still the characteristic “ note of exclamation” figures, the
same as ever. The rays from the lamp must first be rendered
parallel by a bull’s-eye condenser. On now sliding this on the
table sideways, the light will gradually vanish from the object, and
give a dissolving view ; and at last there is only the faint outline of
the scale, with its barely perceptible blue surface dotted over irregu-
larly with minute bright blue circular spots. This appearance is
so different from anything before seen in the Podwra, that were I
to exhibit it as such, not one of its numerous friends would recog-
nize it. But on bringing the light gradually forward again, we
have at once most palpable proof that there is no deception. These
spots of light emanate from the butt-ends of the markings; for
these, having both a higher refractive power, and being also, perhaps
from their prominence, in more intimate contact with the glass, are
the last portions to admit the light, at the time when the angle
becomes so great that the margin is approached, when total reflexion
again begins to prevail in the glass against the less refractive power
of the scale, which causes its transmission.

As the light is again drawn forward, it plays over the individual
markings, and gradually discloses them, from the first bright point to
the taper ends. As in this mode of illumination we see the scale as
nearly as possible as an opaque object, without the false appearances
arising from refraction, I think that it affords some proof that the
markings of the Podura consist, in reality, of the taper bodies
generally known, and which have considerable refractive power and
some amount of opacity, and that there are only one series of them.
But instead of being planted on one side of the scale they are
enclosed between ¢wo membranes. If they were set on one side of
a single membrane some difference would be observable above and
below, and it is well known that there is none. And further, the
unprotected markings could be displaced or detached, if they lay on
the outer surface only ; and, finally, the mode of illumination herein
noticed would merely allow particles of the light to find their way
only through the resting-points of the markings, instead of over the
whole area of the scale. This affords strong proof that there is a
flat membrane in close contact and adhering to the glass surface,
destroying the total reflexion in the entire space occupied by the scale,

30 ; Structure of the [Gee

VII.—Structure of the Adult Human Vitreous Humour.*
By Davin Suita, M.D., M.R.C.S.

Tue almost perfect transparency of the vitreous body has all along
been the chief impediment which anatomists have felt in investi-
gating its structure. When it is examined in the fresh state,
nothing but a few processes and granules can be detected in it
even with the highest magnifying power, and therefore no hope
can be entertained of elucidating its structure without the assist-
ance of reagents. Its minute structure may be demonstrated by
removing a small fragment from the centre of the humour (thereby
avoiding any part of its containing envelope), and placing it on a
glass slide, to which is then added a drop of concentrated alcohol.
This has the effect of instantaneously rendering the tissue of the
humour opaque. Thus treated and subjected to a low magnifying
power, a network of reticular tissue is observed in the field of the
microscope, dragged about in all directions from the commotion
produced by the combination of the alcohol with the fluid of the
humour. As this motion soon whips the delicate network of tissue
into irregular ropy fibres, which no amount of maceration can
again separate, it 1s necessary, in order to observe the structure
more minutely, to cover it immediately after the addition of the
alcohol with a thin pellicle of
lass. Examined with a power
of three hundred diameters, the
network of reticular tissue re-
solves itself into minute tubes
or canals, intersected by cells at
variable, but still very minute
distances apart, thus establishing
an anastomosis between cell and
cell, as well as between the re-
ticulations (Fig. 1a). The tubes
are about the size of the elements
of connective tissue, and the
cells about ten-thousandth of an
inch in diameter.

maser a Aeneas euenrn nite No matter what part of the
cortical portion of the vitreous humour. (Mag- vitreous humour is examined, the
same structure is observed; but

in and near the circumference of the humour, and particularly near
the zone of Zinn, another set of fibres is superadded. These consist

* By the kind permission of Dr. Wakley, we are enabled to reproduce the fol-
lowing remarks, with illustrations, from the pages of the ‘ Lancet.’—Ep. M. M.

thly “Mi ical V2
Monthly Microscovs | Adult Human Vitreous Humour. 31

of strong, smooth fibres, not unlike the fibres of common fibrous
tissue, which form a coarse, open web, in the large meshes of
which the finer network of anastomosing cells is woven (Fig. 1b).
These fibres are evidently for the purpose of giving strength to
the humour in these situations.

The tissue of the vitreous body is entirely composed of an open
meshwork, and nothing in the shape of membranes can be seen in
it with the microscope. But the microscopic examination of the
vitreous humour in detached portions can convey no idea of the
design of its structure as a whole; and contrary, therefore, to
what might be anticipated from microscopic observation, the strong
fibrous tissue, which exists only towards the circumference of the
vitreous body, is discovered by the naked eye to be woven into
membranes or membranous strata, having a determinate direction
within the humour, while the anastomosing cellular tissue, on the
other hand, occupies the intermembranous spaces in the manner
_ of loose connective tissue. |

To demonstrate these membranes and the intermembranous
tissue in their relative situations, it is necessary to have recourse
to another method than that already described, for the purpose of
rendering the parts opaque as a whole, in order that they may be
seen 7m situ with the naked eye. Of the methods which may be
employed for this purpose, the one most conclusive and least likely
to embarrass the observer is that which allows the tissue to become
opaque from age, a small quantity of preservative fluid being used
merely to prevent it undergoing the process of putrefaction. To
accomplish this, the eyeball should be allowed to stand four or five
days in water, when it is to be divested of its tunics, and the vitre-
ous body, with the crystalline lens and capsule, entire, placed in a
solution of carbolic acid, of about the strength of one of the latter
to three hundred of water. At this stage the vitreous humour is
of a straw-yellow or greenish colour, owing to the infiltration into
it of the colouring matter of the blood, which somewhat masks the
view of the fabric within; but in a few days the sanguineous
colouring matter is disseminated into the surrounding menstruum,
leaving the structure of the humour quite apparent to the naked
eye.

A vitreous body, having been prepared according to the pre-
ceding directions, is to be placed in a wine-glass, or other eligible
clear glass vessel, covered with water, and examined with the naked
eye as the direct rays of the sun are condensed upon it by means
of a convex lens. When so examined, the structures within the
humour will be found to have the following arrangement :—

(a) Passing through the vitreous body from the point where
the optic nerve pierces the eyeball to the posterior capsule of the
crystalline lens, but inferiorly and internally to the axis of vision,

; {| Monthly Microscopical
39 Structure of the Journak daly ep,

is the hyaloid canal, which gave passage, in the embryonic eye, to
the hyaloid vessels. It is not a constant structure of the adult
vitreous humour, and in old age not a trace of it can be found. In
some cases, however, it is not only present in the adult, but it
remains patent through the whole of its extent, and in such cases,
after the vitreous body has been macerated, is often seen to contain
opaque granular matter, as if it still conveyed, during adult life,
nutriment for the crystalline lens. ‘The hyaloid canal has a dia-
meter about that of a common probe, and, unlike the same structure
in its primitive condition in the foetus, it gives off no branches to
the vitreous humour.

(b) Arising at right angles from, and surrounding the inner
surface of, the zonula Zinnu, are eight or ten membranous circles,
placed the one within the other ; each circle, on close examination,
being seen to be made up of a series of segments, overlapping and
uniting by their edges—the arrangement not being unlike the
origin of the leaves of a leaf-bud from a circular disc. Proceeding:
from this origin, these membranes take a course backwards to the
entrance of the hyaloid canal, and in their course split horizontally
the entire circumference of the humour into innumerable shallow
cells, placed with their flat surfaces to the hyaloid membrane, which
build up, layer upon layer, the sides of the vitreous body around
the antero-posterior axis of the eyes as a centre (Figs. 2 and 3).

Fic. 2. Fie. 3.

Arrangement of the membranous strata Origin of the membranous
within the human vitreous humour strata from the zone of
(natural size). A, Crystalline lens; Zinn (natural size).. A,
B, Zone of Zinn; C, Hyaloid mem- Crystalline lens; B, Ex-
brane; D, Cortical portion of the treme border of zone.

humour; K, Medullary portion of the
humour; F, Hyaloid canal; G, Ra-
diating fibres.

)

These membranes are made up of the strong, smooth, fibrous
elements already referred to under the microscopic examination of
the humour. When they are examined individually with the naked
eye by the aid of the direct rays of the sun, they are seen to consist
of a flimsy network of fibres, which, for want of a better name,
I have called membranes, though they scarcely admit of being so
classified ; and though I have described as cells the compartments
which the membranes enclose, they are incapable in any degree of
limiting the fluid of the humour. The more superficial membranes,

Monthly Microscopt!] Adult Human Vitreous Humour. 33
or those which take their origin from the extreme border of the
zone of Zinn, have a coarser texture and web than those nearer the
axis of the eye; and the former are also more bent in their course
backwards, following the curve of the hyaloid membrane, in adapta-
tion to the globular form of the vitreous body. In the vertex, or
what may be called the medullary portion of the humour, I have
not been able to detect any distinct membranous layers. Faint
lines may usually be recognized running backwards in this situa-
tion; but they partake of none of the characters of a membrane.
Moreover, the central parts are devoid of the strong fibrous tissue
which forms the basis of the membranous strata of the cortical por-
tion of the humour.

(c) As to the anastomosing cellular tissue, it occupies the medul-
lary portion of the humour behind the crystalline lens and the
spaces between the membranes, in the manner of intercellular
tissue. It is woven into cellular spaces as receptacles for the
vitreous fluid. The filaments of this tissue cross the short dia-
meter of the intermembranous spaces, and therefore they have a
radiating direction from the vertex to the sides of the vitreous body
(Fig. 2); but, inasmuch as they are finer than the fibres of the
membranous strata running from before backwards, they are not
so apparent to the naked eye in the prepared specimen. In fact,
the intermembranous spaces look to the naked eye as if they merely
contain a transparent fluid—a fallacy which is only dispelled by
observing them minutely as the direct rays of the sun are thrown
upon them, or by touching them with a blunt instrument.

Thus it will be found that while the membranes of the vitreous
body are stretched between the zone of Zinn and the fundus of the
eye, the anastomosing cellular tissue radiates from the vertex to the
sides of the humour—an arrangement which offers the best provi-
sion for the prevention of undue distension of the hyaloid mem-
brane from the accumulation of fluid within. It is also not
unworthy of note that the membranes, being the strongest fabric
of the two, offer the greatest resistance to distension in the direc-
tion in which it would be most injurious to vision—namely, in the
direction of the axis of the eye. ‘The crystalline lens and retina
are by such an arrangement maintained at a fixed distance from
each other ; and the delicate retina is also protected from undue
pressure, between the hyaloid membrane, on the one hand, and the
unyielding tunics of the eyeball, on the other.

Such is the structure of the vitreous humour in the adult
human subject. It is so fragile, and the proportion which it bears
to the vitreous fluid is so small, that it is scarcely to be wondered
at that it has escaped notice so long. Its weight makes no appre-
ciable difference in the specific gravity of the fluid of the humour,
which is 1058 ; for if the fluid of the humour be allowed to drain

VOL. II. D

34 Structure of the a aero
away, the residue, inclusive of the zonula Zinnti, hyaloid membrane,
and posterior capsule of the crystalline lens, does not amount to
one grain.

The fluid which occupies the meshes of the vitreous tissue gives
to the humour its solidity, as well as its pellucid and highly trans-
parent quality. It has a consistence intermediate between water
and the serum of the blood. Of the organic constituents of the
blood, the only one which it contains, and that even in very small
amount, is albumen. According to Berzelius, the healthy vitreous
humour has the following chemical composition :—

Chloride of sodium, with a small cae ge of extractive 1°42

matter soluble in alcohol _.. et icm) oe i:
Matter soluble im water | \.2. (.2) +, ea), ee 5) ee eee 0°02
Albumen aa) G0) ae ek ee ee en eee 0°16
Water 2.5 5. eo ae Fcc ee) Mee’ Ge een 98°40
100-00

Millon and Wohler have discovered traces of urea in the fluid of the
vitreous humour.*

The fluid of the vitreous humour is chiefly secreted by the ciliary
processes ; but pathological observation renders it probable that the
vessels of the retina take some share in the same process.{ Inter-
vening between the substance of the humour and the ciliary pro-
cesses is the zone of Zinn—a part of the containing envelope of
the vitreous humour,—which is a structureless membrane, giving
off internally the peculiar structure of the vitreous humour and
externally strong fibres, which bind it firmly down to the ciliary
processes.t The two structures are dovetailed into each other—a
highly favourable relationship for the secretion of the vitreous fiuid.
Through the structureless membrane of the zone of Zinn the
vitreous fluid filters in its way to the humour ; but, like all other
cases in which secretion takes place through membranes without
the intervention of cells, the vitreous fluid consists merely of the
permeable constituents of the blood. The zone of Zinn seems likely
to exercise some influence over the transparency and decoloration
of the vitreous fluid during life, for after death the power to resist
the coloured constituents of the blood is lost, in consequence of
which the vitreous body soon becomes coloured greenish-yellow. A
moderate amount of heat also relaxes this membrane so as to facili-
tate the transudation of fluids through its walls, and consequently
inflammatory action of the neighbouring structures will probably

* Carpenter’s ‘ Human Physiology,’ 4th edit., p. 54.

+ Bowman: ‘Lectures on the Parts concerned in the Operations on the Eye,’
p. 125.

{ The structure of the zone of Zinn, as here stated, will be demonstrated in a
course of lectures on the Eye, which it is my intention to deliver in Glasgow during
the ensuing winter.

Monthly Microscopical! Adult Human Vitreous Humour. 35

have the same effect. It is impossible to say whether, under ordi-
nary circumstances, the secretion of the vitreous fluid is rapid or
slow, but a large quantity is known to be thrown out when occa-
sion requires, as when some of it has become evacuated by accident.
In such cases, however, the structure of the humour will seldom be
reproduced in the fully developed eye.

The fiuid escapes so readily from the humour that it has become
a problem how nature effects its retention. As will have been
observed from the description which has been given of the structure
of the humour, it is such as to afford ample facility for a free and
rapid circulation of the fluid through its substance ; and therefore
any force inherent in the tissue itself, such as capillary attraction,
can have very little effect in holding the fluid in its meshes. Its
retention is readily accounted for by the limited permeability of
its enveloping structure—the hyaloid membrane—during life.
Even after death, when that membrane has lost much of its resist-
ance to permeation, if the vitreous body be exposed entire, the fluid
will take some days to drain away, while a few hours is sufficient
if the hyaloid membrane has been lacerated. From the natural
firmness of the vitreous body, the retention of the fluid has been
accounted for by those who deny that the humour is possessed of
any structure, by the fluid in its normal condition having a certain
consistence resembling jelly, in which case its exhaustion could only
arise from the substance of the humour passing from the semisolid
to the fluid condition. This is disproved by the fact that the fluid
of the humour can be replaced by any other fluid, such as pure
water, spirit, or glycerine, merely by imbibition, and the vitreous
body still retain the same physical properties.

As the vitreous body does not possess any function of a vital
nature, and as it has a temperature amongst the lowest of any
organ in the body, it is evident that it must undergo little decay,
and exercise little demand over the nutritive forces for its renova-
tion. Nevertheless, though it be a non-vascular body, and though
the greater part of it be remote from the sources of the circulation,
as it is known to undergo various rapid changes in disease, it must
possess a proper system of nutrition within itself. In the absence
of all other evidence of a nutritive system within the humour, the
cellular elements described under the microscopic anatomy of the
humour probably contain nutritive materials; and the anastomosis
which exists between cell and cell—to adopt the language of Vir-
chow,” on an analogous nutritive system in Wharton’s jelly of the
umbilical cord,—* renders possible a uniform distribution of the nu-
tritive juices throughout the whole of its substance.” The small
amount of albumen which exists in the vitreous fluid is incapable
in its crude state of being applied to the nutrition of the fabric of

* “Cellular Pathology,’ p. 100. 9
D

36 — “Btructure of the ==. [Micuma,, Suit ees

the humour, and therefore the ciliary processes, as the organs of
secretion of the vitreous humour, have probably less reference to
the nutrition of its structures than the supply of an abundant and
highly transparent fluid for mechanical and physical purposes.

It is a general law in the economy that each atom of the body,
by its inherent vitality, must appropriate and transform for its own
use whatever nutriment it requires. In accordance with this law,
it is the part of the structure of the adult vitreous humour to vita-
lize the histogenetic material which the vitreous fluid contains, for
the renewal of its elements and the maintenance of its trans-
parency. Considered in this light, it is dependent on the ciliary
processes for nutriment only in so far as these organs secrete
abundantly the vitreous fluid, in which is dissolved a small amount
of albumen, but which at the time of its secretion is entirely devoid
of organization. On subjecting a fragment of perfectly fresh
vitreous humour to the action of dilute nitric acid, the fibres of the
anastomosing cellular tissue are observed, under a high magnifying
power, to have strung upon them transparent globules, measuring
about =3>th of an inch in diameter. These globules are quite dif-
ferent, but scarcely distinguish-
able, from the ordinary vitreous
fluid, and may not inaptly be
compared to a string of pearls
(Fig. 4). They consist of a
viscid, highly transparent fluid,
and cling to the fibres by their
own tenacity, or by vital at-
traction ; they have the form
of cells, but they are devoid of
any cell-wall, and the ordinary
vitreous fluid has no effect in
dissolving them; they are so
closely set as to touch each
other, and they completely mask

ly globules attached to the cellular tissue of the the view of the fibres which

fics LSE (Magnified 200 diameters.) they enclose ; and they possess
a high degree of refrangibility.

Spectra of these globules have been long familiar to natural
philosophers and workers with the microscope as frequent sources
of interruption to vision in their scientific investigations ; but until
the present they have eluded the most searching inquiries in the
dead subject. ‘The reason of this is that a few hours after death
they spontaneously detach themselves from the fibres of the humour,
and coalesce into large drops, which in the aggregate have a slightly
yellowish colour. A convenient method by which an observer may
see these globules in his own eye is by looking through a lens of

Monthy Magi es, | Adult Human Vitreous Humour. oF
short focus at the flame of a candle two or three yards distant ; *
but by thus viewing them it would never be suspected that they
enclose the delicate structure delineated in Fig. 1 (page 376). Be-
sides age in the dead subject, these globules are also rendered more
fluid and become detached by the addition of the caustic alkalies, or
by the application of a moderate heat, disclosing the structure
which they obscured ; but they are not dissolved or detached by the
dilute mineral acids. Respecting the nature of the fluid of which
these globules are composed, it presents no tendency to pass spon-
taneously into a state of fibrillation, and therefore it has no claims
to be ranked with lymph or any of the normal fluids of the body
which contain fibrin; and in being quite insoluble in the ordinary
vitreous fluid, it is at once distinguished from albumen, at least in
the condition in which that substance is secreted by the ciliary pro-
cesses. In its behaviour with chemical reagents, and in being with
difficulty coagulated by heat, it answers to the description of the
globulin of the blood. But, whatever name be applied to it, there
can be no doubt that it belongs to the albuminous type of com-
pounds; and as the vitreous fluid, when secreted, contains no other
histogenetic compound than albumen, it seems a safe deduction that
these beautifully transparent globules consist of albumen in the act
of undergoing a metamorphosis into a higher state of elaboration.
As to the office of these globules in the vitreous humour, by forming
an impervious coating upon the fibres of the anastomosing cellular
tissue, they protect the latter from maceration in the fluid in which
it is constantly bathed, and their plastic property will necessarily
add strength to the fibres. But their prime function is, no doubt,
the supply of nutriment for the fabric of the humour, or for other
arts. |
: Assuming these globules to be derived in the manner already
supposed, their formation is dependent on the assimilating power of
the tissue of the humour, which in that case must be endowed with
a certain amount of vitality. We have abundant evidence of the
existence of this force in the humour: in its development in the
embryo; in its organization in the adult; in its undergoing mole-
cular decay, the products of which have been demonstrated in the
vitreous fluid by chemical analysis ; in its constant maintenance in
a state of transparency, though it contains a decomposable struc-
ture ; and in its undergoing the process of putrefaction after death.
It would seem, also, as if the globules adhere to the tissue by the
force of vital attraction; for they become detached of their own
accord soon after death. But if any doubts exist as to the presence

* For the manner in which the structure of the vitreous humour may be viewed
entoptically, see Mackenzie “‘On the Vision of Objects on and in the Eye,” ‘ Edin-
burgh Medical and Surgical Journal,’ No. 164; also James Jago, M.D., ‘On
Entoptics,’ London, 1864, p. 74.

38 Structure of the lee acy

of vital force in the humour, they are at once dispelled by the
evidence of pathology. The vitreous body, or the tissue which it
contains, is subject to inflammatory action; it throws out and
vitalizes inflammatory products into organized tissue, or matures
them into pus; if the tissue of the humour be broken up by the
surgeon, or by accident, reaction comes on; and foreign bodies
become encysted in lymph in the centre of the humour without
obvious assistance from any vascular part of the eyeball. It is
presumed, therefore, that these globules, or beads of plastic fluid,
owe their formation to the anastomosing cellular tissue of the
humour, accumulating around its fibres by its inherent vitality
the albumen which the fluid of the humour contains, and elabora-
ting it by prolonged contact into a compound of higher nutritive
value ; and the obvious relation of these globules to the tissue of
the humour, and their attraction for it during life, give them a
special reference to the process of nutrition. Such a process has
its prototype in the connective tissues of the body (from which the
vitreous humour in the embryo is developed), by the serous fluid
of the blood, itself unorganized, being converted into organized
corpuscles simply by its passage through the meshes of these
tissues. With regard to the reason why the plastic fluid, in attach-
ing itself to the fibres of the humour, assumes the corpuscular or
globular form rather than a smooth, continuous layer, I do not
pretend to offer any precise information at the present time, only
that it is a common physical phenomenon in the operation of capil-
lary force.

But besides protecting and nourishing the structure of the
humour, the pearly globules of its fibres are probably ultimately
destined to serve a still more important end—viz. the nutrition of
the crystalline lens. Almost two-thirds of the latter body is
imbedded in the front of the vitreous humour, both structures
lying in close contact. The cellular tissue of the vitreous humour
converges towards, and is crowded behind, the crystalline body, to
the posterior capsule of which it is adherent, and that so inti-
mately, in the whole of its extent, that the two are never completely
separable. ‘The capsule of the lens is a highly transparent mem-
brane, four or five times thicker in front than behind, and in the
latter situation forms the only intervening substance between
the lens itself and the structure of the vitreous humour. A thin
section made in the direction of its thickness, and rendered partially
opaque by dilute nitric acid, shows it to be channelled by many
tortuous pores, which form indirect communication between its two
surfaces. These pores are occupied by a transparent fluid having
all the characters of the pearly globules of the vitreous tissue.
Near the centre of the posterior capsule a close net-work of
extremely minute capillary vessels exists in many of the lower

monty Muy a wee, | ~=Adult Human Vitreous Humour. 39
animals. The crystalline lens is an isolated body in the interior of
the eye, and is dependent for its nutrition on one or more of the
media which surround it. In many respects its nutrition resembles
the same process in the vegetable kingdom. ‘Thus, its structure
continues cellular throughout the whole of its existence;* it
possesses no nerves, and therefore its nutrition is beyond the influ-
ence of the nervous system; the nutrient fluid which its cells
contain is globulin,t an albuminous compound which has no ten-
dency to assume spontaneously a higher grade of organization ;
and lastly, when the structure of the lens is once fully formed, it is
subject to little change of material. It has long been held that the
lens derives the greater part of its nutriment through the vitreous
humour, but the structure of the latter not having been satisfac-
torily determined, the evidence of this was arrived at by “ eaclu-
sion.’t When the choroid or vitreous humour is inflamed, the
products arising therefrom are abundantly found in the neighbour-
hood of the lens, and the latter also participates in the morbid
action. If the vitreous humour be disorganized, or a great part of
it lost by accident through a wound of the tunics of the eyeball,
without injury of the lens, cataract follows; while if the lens be
dislocated from its ligamentary attachment, but still adherent to the
vitreous body, it generally remains transparent, unless the latter
be disorganized. ‘The convergence of the anastomosing cellular
tissue of the humour to the posterior surface of the lens indicates
an intimate association of the nutrition of the two structures, and
this is peculiarly borne out by the structure of the humour in birds.
In that division of the animal kingdom the lens undergoes more
rapid molecular changes than in any other, and the individuals of
this class have a special provision existing within the eye for the
supply of the extra demand which necessarily falls upon the nutri-
tive processes. This consists of a process of the choroid, called the
pecten, which passes through an opening in the retina at the bottom
of the eye, and forward in the substance of the vitreous humour to
near the posterior surface and external margin of the lens. Filling
up the link between the tip of the pecten and the lens is the anas-
tomosing cellular tissue of the humour, which radiates in straight
lines from the former to the latter, thus establishing a communica-
tion between the vascular choroid and the lens, and which it will
scarcely be doubted conveys nutriment to the latter.

These facts point to the vitreous humour as being the principal
source through which the lens is nourished, thus confirming the
hypothesis which has all along been entertained ; but the manner

* Carpenter’s ‘Human Physiology,’ 4th edition, p. 254.

+ Op. cit., p. 254.

} The structure of the humour, as now revealed, renders this supposition almost
a certainty.

Monthly Mi ical
40 Structure of the onttity aiteanaeepics

in which this takes place has never been explained. As the aque-
ous humour and the ordinary fluid of the vitreous humour contain
only a fractional part of formative material, which, moreover, is
entirely destitute of organization, the transudation of these fluids
through the capsule, in sufficient quantity to be of any service in
the nutrition of the fully-formed lens, would, from the experience
we possess of its nature, tend to its disorganization and opacity
rather than its nourishment and transparency. Indeed, the capsule

of the lens possesses a power which, whether vital or elastic, pre-

vents the transudation of watery fluid through its walls during life
—a power which it loses soon after death, and then it allows ingress
to the fluid humours of the eye. The same force confers upon it an
elective affinity by which it is enabled to take up the small amount
of albumen dissolved in the aqueous and vitreous humours; and,
therefore, the anterior capsule is probably also concerned to a small
extent in the nutrition of the lens. But considering the facts
already stated as to the close relationship of the vitreous body and
lens, coupled with the additional fact that the anterior capsule is
four or five times thicker than the posterior, we must regard the
vitreous humour as the reservoir of its nutritive supply. The
plastic substance which I have described as adhering to the vitreous
tissue in the form of globules is the only compound which the
vitreous humour contains capable of undertaking this office, for
which it seems well suited in every respect. Its immiscibility in
the ordinary fluid of the vitreous humour enables it to be conveyed
to the lens in a concentrated state, ready to be received as nutri-
ment by the latter; its plasticity and higher degree of vitality
than the ordinary vitreous fluid give it a greater vital and physical
attraction for the capsule; while its identity in chemical and phy-
sical properties to the fluid that pre-exists in the cells of the
crystalline lens makes it as nearly as possible a certainty that it is
the pabulum of that body. As the pearly globules have no proper
cell-wall, and are not confined to tubes, the onward movement of
these to the lens as the latter has a demand for them must be
mainly owing to that vital attraction which everywhere exists
between pabulum and tissue, and which in the body generally exerts
so much influence on the onward movement of the blood in the
capillaries. In the present case, however, the elasticity of the fibres
on which the globules are strung, as well as the tension of the
humour generally, will combine with the vital attraction to give
these globules an onward movement corresponding to the direction
of the fibres, which is centripetal, or that towards the lens. Thus
the crystalline lens of the eye is supplied with transparent nutri-
ment for the repair of its waste by a simple and highly eligible

rocess. It demands its nutriment in a state of concentration and
in a high degree of transparency. ‘The colourless elements of the

°

Monthly Microscopical) Adult Human Vitreous Humour. 41

blood are those only capable of being applied to the nutrition of
non-vascular parts; but these elements exist in solution in the
serum of the blood in such insignificant quantity, that if the latter
were applied directly to the lens it would at once destroy its trans-
parency. But Nature overcomes this obstacle by causing the
serum of the blood first to pass through a structureless membrane—
the zone of Zinn—to insure its transparency, and afterwards among
the meshes of a living structure to separate the formative material
from the mass of the fluid in which it is dissolved, and thus by
enhancing its vitality renders it capable of ministering to the repair
of the lens. This view of the vitreous humour magnifies the
importance of its function as a component part of the eye, and makes
it as essential to the health of the lens in the adult as it 1s to its
development in the foetus. Both in the foetus and adult the vitre-
ous humour is to the lens what the roots are to the plant: it selects
the erude material from the blood, elaborates it into nutriment
within itself, and, having satisfied its own demands, conducts it
onward to the crystalline lens.

As the vitreous humour is one of the chief agents which contri-
butes to the fulness of the globe of the eye, the relation which it bears
to the healthy hardness of the latter comes next under consideration.
But as the aqueous humour and crystalline lens also contribute a
small share in the production of intraocular tension, these last must
also be passed in review during the discussion.

Intraocular tension is essentially based upon the distending
force of the fluids of the eye, enclosed by membrane and tissue,
which give them the character of a spherical solid body. It pre-
supposes two conditions—first, the distending force of the fluids ;
and, second, the reaction of the membranous sphere upon the fluids.
Both of these forces are in constant operation in the healthy
eye, and between them, in health, an equilibrium exists, whereby
neither gains the ascendency. ‘The last of these will be considered
first.

The contents of the eyeball—the aqueous humour, crystalline
lens, and vitreous humour—are enclosed within a structureless
capsule, which serves to bound and limit them, and unite them into
a glassy sphere (Fig. 5). That segment of the sphere which cor-
responds to the posterior hemisphere goes under the name of
hyalowd membrane (B); that in the anterior hemisphere, the
posterior elastic lamina of the cornea (A). These membranes are
united in the ciliary body (D), which throws the two segments into
a sphere. This union may be demonstrated by making a section
of the tunics of the eyeball in their thickness, parallel to the course
of the ciliary processes. In such a preparation the posterior elastic
lamina (A), after surrounding the anterior chamber in front, as a
homogeneous structureless membrane 1-2000 to 1-3000 of an inch

42 Structure of the [Soames daly 480

in thickness,* is observed, at the margin of the cornea, to become
fibrous and to divide into three parts. One part encircles the rim
of the anterior chamber, limiting the fluid which it contains, and
passes into the base of the iris and into the ciliary body, in the

‘ latter of which situations it

Pea becomes blended with the
fibrous processes of the zone
of Zinn. Of the other
parts,. the greater gives
origin to the ciliary mus-
cle, which is also inserted
into the ciliary body ; while
the lesser portion (HE) enters
the sclerotica, enclosing the
canal of Schlemm. By the
i latter attachment the scle-
rotic 1s indirectly connected
with the ciliary circle.
Again, the hyaloid mem-
brane (B), after encircling
the posterior hemisphere
as a thin transparent mem-
Diagram of the Aqueous Capsule of the Eye. brane, is fir uly bound down

A, Posterior elastic lamina of the cornea; B, Hyaloid mem- to the cihary body, wher €

brane; C, Structureless membrane of Zinn; D, Union +4 ; 1 1
* of the membranes of the two hemispheres in the ciliary ib Increases In thickness,

body ; EK, Fasiculus of fibres which enclose the canal of and goes under the name
Schiemm ; F, Crystalline lens; G, Ligament of the an-
terior capsule ; H, Ligament of the posterior capsule. of the structureless mem-
brane of Zinn (C), from its
discoverer. ‘This union is effected by strong fibres which are given
off from the external surface of the latter, pass into the substance
of the ciliary body, and meet those, already referred to, coming
from the posterior elastic lamina of the cornea. Thus, then, these
two membranes become united in the ciliary circle, and form a
structureless sphere, the function of which is essentially that of
limiting the humours which it encloses. For brevity of description
I shall call this sphere the aqueous capsule of the eye. _

The parts contained within the aqueous capsule are, the aqueous
humour, iris crystalline lens, and vitreous humour. It is divided
into two segments by the lens (F') and its ligaments (G H); but the
division is such as to admit of a certain amount of imbibition between
the two hemispheres. ‘This latter fact is of the less importance, as
the fluid in the two hemispheres is chemically and physically alike,
comes from the one source, distends both hemispheres with an equal
degree of force, and its amount in both is regulated by the same
principles.

* Bowman : ‘ Lectures on the Parts concerned in Operations on the Eye,’ p. 19.

eo sus se | Adult Human Vitreous Humour. 43

The vitreous tissue in the posterior segment, and the posterior
elastic lamina of the cornea in the anterior segment, confer upon
the aqueous capsule the property of elasticity in a high degree, so
that it is able to resume its original shape after it has been altered
by any of the physiological actions of the eye. The elasticity of the
vitreous tissue has been already adverted to (vol. 11. 1868, p. 378).
Further evidence that it is possessed of this physical property might
be multiplied. I will only mention one other example. Place a
fragment of vitreous between two slips of glass, previously rendered
opaque by a weak solution of nitrate of silver, to enable its action
to be more readily observed. On pressing the glasses in contact
the vitreous tissue is observed to expand, and on removing the
pressure it instantly regains its former size. The hyaloid membrane
is not extensible, though it bears a greater strain than might be at
first supposed. The elasticity of the limiting membrane of the
anterior hemisphere is a well-established fact.* The elastic struc-
tures of the aqueous capsule of the eye contract upon the contained
fluid, and give it the character of a solid sphere. In the healthy
state of parts it is always full, offering in front a smooth surface for
the perfect refraction of the rays of light, and behind for the close
adaptation of the retina which is spread out upon it.

But not only is the aqueous capsule, in health, always full, but
the fluid which it encloses subjects it to a distending force, against
which it reacts in an equal degree, The distending force to which
the anterior hemisphere is subjected is often illustrated in practice
in cases of ulceration of the cornea. The posterior elastic lamina,
in these cases, in losing the support of the lamellated tissue in front,
may often be observed to protrude through the bottom of the ulcer
in the form of a vesicle. ‘This is caused by the distending force of
the fluid within. The distending force of the vitreous body is illus-
trated by the pressure effects on the central vein of the retina. In
the normal state of parts the central artery and vein of the retina,
as they pass over the optic disc, are raised above its surface, and are
in direct contact with the hyaloid membrane, even projecting some-
what into the substance of the vitreous. In such circumstances the
artery does not show any signs of pulsation, but the vein does in
many cases; and in all the latter is flattened by the pressure of the
vitreous, and pulsation is easily provoked in it. Now, the pulsation
of blood-vessels, in any case arises from the resistance which the
walls of the vessels or outlying structures give to the distending
force of the blood. While, in the eye, therefore, the distending
force of the vitreous humour is insufficient to compress the arteria
centralis retinze to that degree which will give rise to pulsation, it
ig sufficient to flatten the vena centralis retine, and to give rise to
pulsation, or an intermittent current of blood over the optic disc.

* Bowman: Op. cit., p. 19.

44, Adult Human Vitreous Humour. [Monthly Microscopical

As the vein, in this case, is as much subjected to the pressure of the
vitreous as if it were in the centre of the humour, an index of the
distending force of that body is thus obtained, which may be roughly
estimated as equal, or slightly superior, to the lateral pressure of the
blood in the smallest veins.

The distending force, however, to which the aqueous capsule is
subjected by the fluid which it encloses is confined within the
capsule itself; outside the capsule the distending force ceases to
exist. ‘This may be illustrated by the following experiment :—In a
dying person, or in a body immediately after death, when the heart
is either failing i power or has ceased to beat, the only obvious
physical difference in the eye in such a case and that of a person in
the vigour of life is, that the choroid has partially emptied itself of
blood, and the sclerotica has become soft from the want of support
within. In such circumstances, if pressure be made on the eyeball
with the two forefingers, the vitreous is felt as a hard globular body
within the eye, apparently of its normal position and size. Now,
if the vitreous communicated any distending force beyond the
hyaloid membrane to the outer tunics of the globe, or if the latter
reacted by an elastic force upon the vitreous body, the tension of
the eyeball would not diminish in the ratio of the weakness of the
heart’s impulse, but the place of the receding current of blood would
be taken in the one case, by the distending vitreous, in the other by
the contracting tunics. That the distending force of the fluids of
the eye is borne entirely by the aqueous capsule and structures
within it, is also deducible from the difference between the form of
the eyeball in health and that which it assumes in some diseases.
In the normal eye the aqueous capsule forms a sphere (of which
the cornea constitutes a segment), the radius of which is somewhat
less than that of the sclerotica, and which cuts the latter at its
junction with the cornea. The cornea therefore is more convex
than the sclerotica, and at the line of junction a slight depression
exists, on account of the angle which the two structures form with
each other. The sclerotica forms no part of the sphere, and there-
fore can sustain no part of the distending force of the fluids of the
eye; for if it did, the cornea and sclerotica would be segments of a
sphere having the same radius. But when the aqueous capsule
becomes enlarged by a superabundance of fluid, such as occurs in
glaucoma, the lesser sphere (the aqueous capsule) becomes enlarged,
so that the distending force formerly borne by it comes to bear
upon the sclerotica; in a word, the lesser sphere merges into that
of the sclerotica, and, as a consequence, the cornea takes on the
curve of the latter tunic, the depression which normally exists at
the junction of the two structures becoming obliterated.—Lancet,
May 8th, e& ante. |

Be ue ee Chloride of Gold in Microscopy. 45

VIII.—On the Use of the Chloride of Gold in Microscopy.
By Tuomas Dwicurt, jun., M.D.

Prrnars no re-agent has of late years played so important a part
in microscopy as chloride of gold. By means of it Conheim first
demonstrated the terminations of the nerves in the cornea; and
since it has been very generally used, particularly in investigations
of the nerves. Its application is very difficult, and it is only after
a long series of experiments and failures that proficiency is ob-
tained.

Having had considerable experience with this re-agent in the
laboratory of Professor Stricker, in Vienna, and having obtained
some very satisfactory results, I hope that a few words on its appli-
cation may not be out of place. The chloride should be dissolved
in distilled water, and the solution should never be stronger than
the half of one per cent. The object to be examined should be as
fresh as possible, and should remain in the fluid from three minutes
to perhaps an hour, according to its affinity for the re-agent, during
which time it assumes a pale straw colour. If the piece be small
enough to be readily acted upon, ten or fifteen minutes is almost
always sufficient. It is then laid in distilled water, to which just
enough acetic acid has been added to give it the faintest possible
re-action. In two or three days it will have become purple, verg-
ing sometimes on blue, sometimes on red; the latter is the least
favourable. The preparation is now enclosed in glycerine, and
improves for several days as the colour becomes deeper and as the
finest fibres are the last to be affected. If the experiment has
succeeded—for it sometimes unaccountably fails—the picture pre-
sented is one of the most beautiful and instructive that can be
imagined. ‘The nerves, muscular fibres, and fibrous tissue appear
black on the purple background. Epithelial cells are also coloured,
but not so well as by nitrate of silver.

Although the colour makes fibres visible which are so fine that
they can be seen by no other method, it does not determine their
character. To prove beyond all doubt that a minute fibre is a
nerve, we must be able to follow it to a larger branch. On a very
successful preparation of the cornea of a frog, I observed nerve-
fibres of such minuteness that with a magnifying power of nearly
two thousand diameters it was impossible to follow them to their
terminations. I particularly endeavoured to verify the connection,
asserted by Kiihne but not generally accepted, between the nerves
and the corneal corpuscles. With every advantage, such a connec-
tion is very difficult to prove. I often thought I had found one;
but, when examined by a higher power, and placed in different

46 Chloride of Gold in Microscopy. . | Mpnthly, Microscopical
lights, it proved to be only apparent, except in a single instance,
and then it was not certain that the fibre in question was a nerve.
I mention these facts as proofs of the value of the method ; for it
is no paradox to say that the better the preparation the more dif-
ficult it is to obtain results. As the magnifying power is increased,
elements come into view, which, by inferior methods, are never
seen; and spaces are discovered between bodies supposed to be in
connection. The use of the chloride of gold, however, is not yet
thoroughly understood, and offers a large field for original investi-
gation — rom the ‘ Boston Medical and Surgical Journal, May
27th.

Monthly Microscopical
Journal, July 1, 1869. ( 47 )

NEW BOOKS, WITH SHORT NOTICES.

Vegetable Teratology. An Account of the Principal Deviations from the
Usual Construction of Plants. By Maxwell T’. Masters, M.D., F.LS.
Published for the Ray Society by R. Hardwicke. 1869.—Whether
teratology can be profitably studied, to the exclusion of normal
histological structure, is a question which we think must be an-
swered in the negative. Therefore, though doubtless readers of
Dr. Masters’ work are supposed to be already familiar with struc-
tural botany, we fear that the minute details of vegetable mor-
phology requisite to a comprehension of the facts recorded by
Dr. Masters are not familiar to many. For this reason, we
fancy that save among the higher class of botanists this new
book of the Ray Society’s will not find many admirers. The
author has spared no pains to chronicle examples of abnormal
structure, and the illustrations in his pages are both numerous
and good. We think, too, that most persons will agree with the
author’s conclusion, that all monstrosities are not things sui
generis, but are merely degrees of multiplication of normal
arrangements of parts. But we certainly think it is to be re-
gretted that the facts of normal development of plants were not
worked into the text of Dr. Masters’ treatise. Of what value are
teratological facts if not to clear up our difficulties as to vegetable
morphology? Yet from the omission of general plant anatomy
and histology, the record of Dr. Masters, valuable as it is, loses
much of its usefulness. It seems to us, too, that the author has
employed the microscope to a smaller extent than the subject
demands. We may, of course, be wrong in this; but we are
struck by the fact that many of the continental workers who
have lately sought to determine the relation of the axial to the
foliar organs have relied on the distribution of the vascular
tissues, and have rested on this with advantage. Dr. Masters,
however, gives us very little information on these points; and
yet we should think that in many cases, where doubt must other-
wise exist as to the source of an unusual structure, the microscope
would be a sort of crucial test. However, it must in justice be
stated that the author disposes of this difficulty by a proposition
to which he nearly absolutely assents, viz. that there is no distinc-
tion at all between axial and foliar elements. We believe it was
Locke that quashed the argument between two metaphysicians,
who disputed as to the attributes of the soul, by explaining that
it was first requisite to prove the existence of such an entity.
Dr. Masters places disputants of the Schleiden school in a similar
predicament. This, however, is also a question in some measure
for the microscopist, and we do not think that Dr. Masters has
offered us any satisfactory testimony in regard to it.

We are disposed to think that the author has not quite made
up his own mind on this question of the existence of distinct
elements, axial and foliar, or else we are at a loss to understand the

Monthly Mi ical
48 PROGRESS OF MICROSCOPICAL SCIENCE. = | "your uiy 1 10s,

tone of the statements in pages 481 to 484. Thus in dealing with
the question as to the nature of an “inferior” ovary, Dr. Masters
infers that it is foliar, and as evidence of this he cites, among other
circumstances, the proposition of “the morphological identity of
axis and leaf-organ ;” but a little further on, discussing the origin
of the ovule and its coverings, he declares, in a very positive
manner, that the nucleus is axial and the coverings are foliar.
Now, why should the principle apply in the one case more than
in the other? Perhaps Dr. Masters will explain.

The great bulk of the text is, of course, of non-microscopical
interest, but the treatise is necessarily one of high importance to
the scientific botanist, and Dr. Masters must be complimented on
having discharged so well a most difficult and tedious task.

PROGRESS OF MICROSCOPICAL SCIENCE.

Apparatus for Injecting Specimens.—An apparatus which is in some
measure automatic, and which, at all events, does away with the necessity
of a syringe, but which is hardly novel in conception, is described by
Herr D. Toldt in the last number of Max Schultze’s Archiv fiir Mikro-
skopische Anatomie (5 Band 2 Heft). The author gives an account of
three methods increasing in complexity. The first consists simply of
two flasks, and atube fora mercurial column. The first flask contains
the injection fluid, and its cork is perforated by two tubes—one carry-
ing the fluid to the specimen, and the other connecting it with a second
flask. This latter is connected with a long tube, funnel-shaped at the
extremity, and into which mercury is poured. By this contrivance,
the mercury pressing on the air in the first flask presses also on the
air in the second, and thus the fluid is steadily compressed and forced
into the vessels of the specimen. The mercury flask is provided below
with a stop-cock, through which, when the mercury has descended from
the perpendicular tube, it may be drawn off for subsequent use. The
other two forms of apparatus are a little more complex, and need
diagrams for their explanation, but the principle is much the same,
water pressure being used instead of mercurial, and manometers
being used to gauge the force with which the fluid is pressed on. Any
one who has ever worked in a chemist’s laboratory can readily under-
stand how the pressure of an ordinary water-tap may be utilized for
the purpose of injection. Herr Toldt’s idea is based on the method
so often adopted by chemists.

The Reproductive System of Saprolegnia monoica.—Herr J. Reinke
has given a very minute account of this part of the developmental history
of Saprolegnia. He describes very minutely the different steps in the
formation of the oogonium, and details the production of the antheri-
dia, and illustrates his observations by a plate. See Max Schultze’s
Archiv, ibid.

Terminations of the Nerves in the Pancreatic and Salivary Glands.—
Herr Pfliiger continues his researches on these points, but he does
not add many facts to what he published a few years since. Pfliiger’s

MOU, July Loos | PROGRESS OF MICROSCOPICAL SCIENCE. 49
idea is that the nerves end in the secreting cells, and his drawings
tend less or more to confirm his assertion. The illustrations to the
present two papers (Max Schultze’s Archiv, ibid.) do not bear him out
as fully as those annexed to his earlier paper. Indeed, we are puzzled
to believe that the drawings are not generalized, 7. e. that they do not
represent the observations of several specimens rather than one. We
have worked a good deal at both salivary and pancreatic lobules, and
with powers higher than Pfliiger’s (600 diameters), but we certainly
never saw anything like the definition of structure he depicts, nor were
we able, as he appears to be, to distinguish the fine connective tissue
fibres from the fine nerve fibres. It must be said for Pfliiger that he
used osmic acid, which is stated to bring out nerve structure in a
remarkable manner.

The Histology of the Muscular Tissue of the Invertebrata.—Besides
the paper we have already mentioned as contained in the last number
of Schultze’s Archiv, is a most valuable and elaborate contribution by
V. G. Schwalbe, of Amsterdam, on the characters of the muscular
fibres in most invertebrate animals. He goes through several types,
beginning with the Actinia, and ending with Hchinoderms and
Gastropods. Two handsome folding plates illustrate the memoir,
and represent the muscular fibres as prepared with chromic acid,
bichromate of potash, and osmic acid, and seen with a No. 10 Hart-
nack’s immersion lens. The fibres of some of the annelids (like
Nereis) are peculiar in possessing a number of lateral processes In
others the sarcolemma is indicated, though it may of course be asked
in how far it is a post-mortem or artificial structure, or how far it is
represented by the connective tissue which unites the muscular fibres
together. The markings on some of the fibres can hardly be taken to
represent striez. They rather recall the appearance seen on badly
illuminated specimens of certain diatomacez.

Foreign Microscopes.—Again referring to the last issue of Schultze’s
Archiv, we find an interesting, though sketchy account, by Dr. Leopold
Dippel, of the different microscopes which may be had abroad, and
which are sufficiently good for general work, for hospital use, and so
forth. The prices and the names of makers are in all cases given.

The Structure of Bryozoa.—The anatomy of Cyphonautes and of
Membranipora is given by Herr A. Schneider, in a memoir of nearly
20 pages. The plates contain several well-drawn figures, illustrating
the anatomy of C. compressus and M. pilosa. The author deals with
the mode of classification also. Schultze’s Archiv, 5 Band 2 Heft.

Reichert and Du Bois Reymond’s Archiv.—The last number (May)
of this contains hardly any histological matters, though it has some
anatomical papers of considerable interest.

The Central Nervous System of Birds and Manmals.—It would be
impossible to abstract the lengthy memoir on this subject, by Dr.
Stieda, of Dorpat, in Siebold and Kolliker’s Zeitschrift Etsy | It
extends over more than 90 pages, and treats of the microscopic relation
of cells and fibres in both the brain and spinal cord. The plates are
three in number, and embrace about 60 beautifully drawn figures.

_ The Development of Alciope——Dr. Buchholz, of Greifswald, has
given a short account of the development of the curious annelid,

WOT. EH; EK

50 PROGRESS OF MICROSCOPICAL SCIENCE. [ee eT aBos,
which is parasitic on Cydippi, and which was studied by MM. Claparéde
and Panceri. He gives a magnified coloured figure of the larva of
the animal, and proposes to call it Alciope Pancerii.—Siebold and
Kolliker’s Zeztschrift. May.

Crustacea Parasitic on Ascidians.—The above-named naturalist,
Herr Buchholz, has published a magnificent memoir on these animals,
in the May number of Siebold and Kolliker’s Zettschrift. It minutely
describes a multitude of forms, and is accompanied by seven folding
plates, giving handsome enlarged coloured illustrations of some very
singular crustacean parasites.

Development of the Organs of Generation in Phallusia—M. Paul
Stepanoff has published a short account of the development of the
reproductive system in Phallusia. A quarto plate illustrates the
paper.— Bulletin de ? Académie Impériale des Sciences de Si. Pétersbourg,
t. XTIT.

Comparative Embryology.—Professor Metschnikow is publishing a
sort of mélange of his observations on development. In the Bulletin
of the St. Petersburg Academy above cited he describes his researches
on the following :—Metamorphoses of Suncularia ; Development of
Ophiolepis squammata ; Metamorphoses of Ophiuride ; Metamorphoses
of Nemertes; Development of Bothrocephalus proboscideus; 'The
Larva of Botryllus; On the Development of Ascidians—in describing
this, he refers to a structure which he thinks corresponds to the
Chorda dorsalis of Vertebrates !—On the Embryology of Scorpions.

Structure of the Wing in Orthoptera.—M. de Saussure concludes
his paper on this subject in the Annales des Sciences Naturelles, t. X.,
May. ‘The author here sums up the conclusions he draws from his
observations. These, however, are hardly of interest to microscopists,
as they deal nearly solely with the methods in which the wing is
folded under the elytron.

Anatomy of Pericheta.—Those interested in the structure of the
earth-worm group will do well to read a paper “On the Anatomy of
Two Species of the genus Pericheta” by M. Leon Vaillant, in the
last Annales des Sciences Naturelles. The anatomy is tolerably fully
stated. 'The cerebral ganglion resembles that of the earth-worm, but
the division into two parts is less distinctly marked. ‘The digestive
apparatus is, he says, extremely like that of the earth-worm. Herma-
phroditism is the rule.

The Adenoid Tissue of the Nasal Part of the Pharynx is an excellent
paper in the Journal de l Anatomie (June), by Professor Luschka, of
Tibingen.

The Mucus of the Arch of the Pharynz is also a good, though brief,
paper in the same journal, and by the editor, M. Ch. Robin.

The Structure of the Axis-cylinder of Nerve.—According to M.
Grandry’s late observations, the axis-cylinder is not a uniform, homo-
geneous filament, but is composed of a number of discs of two kinds,
alternating with each other, and arranged end to end.—See Robin’s
Journal, June.

The Proliferation of the Connective Elements of the Perivascular Canals
of the Central Nervous System in Children is a paper of two or three
pages by M. Lépine in the Archives de Physiologie for June.

wera July 160 | PROGRESS OF MICROSCOPICAL SCIENCE. 51

The Sleep of Plants is hardly a histologic paper, but we call atten-
tion to it, as it may interest our readers. It is by M. Ch. Royer, in
the Botanical Section of the last Annales des Sciences Naiurelles, May.

Brunetti’s Process for preparing Anatomical Specimens.—Brunetti’s
process has this advantage over some others (such as those of Gorini
and Segato), that it is adapted to specimens intended for microscopical
examination. The following is an account of the process. It consists
of four stages, namely, washing, divesting of fat, treating with tannin,
and desiccation. A stream of pure water is injected through the blood-
vessels and secretory ducts of the part to be preserved ; the water is
afterwards expelled by means of alcohol. To remove the fat, the
vessels are in like manner injected with ether, which penetrates the
tissues and dissolves all the fatty matters. These operations occupy
a couple of hours, and the object thus prepared may then be kept for a
long time in ether if desired. A solution of tannin in distilled water
is next injected in a similar manner, and the ether washed out by a
stream of pure water. The desiccation is accomplished as follows :—
The preparation is placed in a double-bottomed vessel containing
boiling water—a sort of bain marie—in order to displace the fluid
previously used by dry, heated air. Air compressed in a reservoir to
about two atmospheres is forced into the vessels and ducts through
heated tubes containing chloride of calcium; all moisture is thus
expelled and the process is completed. The preparation thus treated
is light, and retains its volume, its normal consistence, and all its
histological elements. The most delicate sections may be practised
in any direction, and accurate observations made with the microscope.
The relative position of the organs and tissues being preserved, much
better opportunities for pathologico-anatomical demonstration are
afforded than by the former inadequate method of preservation in
alcohol. The blood being expelled, pathological coloration is alone
perceptible.

A New Process for Photomicrography.—M. Bourmans has described
(Les Mondes, May 27th) a method which, though it has some imper-
fections, may be found useful. It is described and somewhat severely
criticized in the ‘ British Journal of Photography,’ from whose pages
we take the following description :—‘“ The plan consists in employing
an ordinary microscope having a mirror fixed in the tube between the
eyepiece and the object-glass of the instrument. This mirror is lightly-
silvered glass, and the light reflected from its surface is thrown out
of the instrument laterally, and at a right angle to the course of the
rays leaving the object-glass. The rays so deflected from their ordi-
nary path pass on and are received on a focussing-glass or on the
sensitive plate. But the mirror, while reflecting a large proportion of
the rays, transmits, according to M. Bourmans, about 25 per cent.
of the total light which it receives, and the rays so transmitted pass
on to the eyepiece of the instrument and finally reach the eye of the
observer. When an object has to be photographed, it is suitably
placed on the stage of the microscope, and viewed in the ordinary
way through the eyepiece of the instrument. It can then be accu-
rately focussed by means of the small amount of light passing through
the mirror. Having placed the sensitive plate in its carrier, but pro-

E 2

sy PROGRESS OF MICROSCOPICAL SCIENCE, [Monty ics

tected from light by a shutter, the object is now caught at the right
moment, the shutter turned aside by means of a milled head, and
the plate exposed for a suitable time. Even during exposure the
object on the stage can be watched in the usual way through the eye-
piece of the instrument without in any way interfering with the pro-
cess.” Our readers will perceive that the principle is the same as
that employed in illuminating opaque objects under high powers.

The Structure of the Pancreas.—In a memoir presented to the
Académie des Sciences on the 31st of May, M. Giannuzzi stated the
results of his observations on the pancreas. They are briefly as
follows :—(1.) The excretory canals of the pancreas have very delicate
walls, which are lined by a cylindrical epithelium. They have not the
same connection with the secreting follicles as the salivary ducts
have, but they form around these a network of fine tubes, which have
no epithelium, and which enclose in their meshes the pancreatic cells.
They may be compared to the biliary networks. (2.) The network
of the excreting canals of different vesicles, which form the same
glandular lobule, form connections to constitute a common network.
(3.) The blood-vessels follow the general course of the ducts. They
surround the vesicles, as capillaries which lie in the meshes of the
network of ducts. (4.) The pancreatic vesicles have no wall. (5.)
The pavement-epithelium of the vesicles is formed of flattened cells
with a nucleus and prolongation. They are very like those of the
salivary glands, but the nuclei are more readily seen, and the contents
are more fatty and granular. (6.) The injections of the pancreatic
canals were made with Prussian blue, and that of the blood-vessels
with gelatine and carmine. The apparatus employed was the pressure
apparatus of Ludwig. 7

The Histology of the Lips of the Infant.—In a paper lately presented
to the Vienna Academy, Herr Klein gave an account of the struc-
ture of the lips of the new-born child, The histologic structure of these
organs allows of three regions being distinguished in them, which are (1)
the epidermal region, (2) the region of transition, and (3) that of the
mucous membrane. The buccal cavity of the new-born child exhibits
towards its anterior portion conical papille elevated a millimétre
above the surface of the epithelium of the mucous membrane. The
author describes a new system of muscular fibres distinct from the
annular fibres of the sphincter of the mouth, and from the fibres
penetrating the cutis, described by Herr Langer.

Fossil Bryozoa.—At the meeting of the Kaiserliche Akademie of
Vienna on the 17th of June, Professor Reuss read a notice upon “ The
Bryozoa of the Tertiaries of Kischenew in Bess-Arabia.”

The Origin of Bacteria.—A memoir on this subject has been written
by Dr. Polotebnow, of St. Petersburg. The chief results arrived at
by this observer were communicated to the Vienna Academy at its
meeting on the 3rd of June by Professor Wiesner. The author states
that Bacterium, Vibrio, and Spirillum are all developmental stages of
Penicillium glaucum. The formation of Vibrio from Penicillium may
be observed when the spores are maintained at a high temperature.

aie ee NOTES AND MEMORANDA. 53

NOTES AND MEMORANDA.

The State Microscopical Society of Illinois—This young but
thriving association, whose charter of incorporation we last month
published, held a grand soirée on the 28th of May last. A large
number of interesting objects were exhibited. There was, we learn,
an excellent display of microscopes on the part of the Society itself.

What to See, and How to See it.—Mr. Metcalfe Johnson’s note
on this subject we cannot insert; not because it is devoid of interest,
but because—as its author is, of course, well aware—it really puts
forward nothing that is not to be found in any text-book on Natural
Philosophy.

Illumination of Objects under the Microscope—For similar
reasons to those above given, we have been unable, in our Reports of
Societies, to insert Mr. Abraham’s (Liverpool) paper. We recom-
mend him to read two articles—one by the President, and the other
by Mr. Wenham—in the present number.

The British Association will this year hold its meeting at Exeter,
under the presidency of Professor Stokes. A great many histological
papers are expected. The Natural History departments will be pre-
sided over as follows:—Geology: President, Professor Harkness,
F.R.S.; Vice-Presidents, Mr. W. Goodwin-Austen, F.R.S., and Mr.
W. Pengelly, F.R.S. Biology: President, Professor Rolleston, F.R.S.;
Vice-Presidents, Mr. I. Spence Bate, F.R.S.; Mr. E. B. Tylor.

The Hunterian Professorship at the College of Surgeons.—lIt is
reported that Professor Huxley has resigned the chair, and that he
will be succeeded by Mr. W. H. Flower, F.B.S., the present Conserva-
tor of the Museum.

The French Academy’s Prizes in Histology,—At the meeting of
the Academy, on the 14th of June, the awards of the several prizes
for the year were announced. The prize of Experimental Physiology
was given to M. Gerbe for his researches on the ovum in relation to
the cicatricule and the vesicle of Purkinje. The Goddard prize was
given to M. Ercolani for his researches on the utucular glands of the
Uterus. The Désmazére was given to M. Nylander for his researches
on the Lichen-flora of New Grenada. .

The American Association for the. Advancement of Science will
hold its eighteenth meeting at Salem, on Wednesday, August 18th.
It is intended to give great prominence to microscopy, and the com-
mittee have issued a special prospectus calling on microscopists to aid
in sending instruments and specimens. Communications should be
addressed to Mr. F. W. Putnam, the Local Secretary, Salem, Massa-
chusetts. The titles of papers should be handed in as early as pos-
sible, in order to secure their presentation to the Association. Each
title should be written on a separate slip of paper, with the author’s
name and address, and an estimate of the number of minutes required
to read the communication. As soon as practicable after entering the
titles, the paper itself, or an abstract, must be handed to the Secretary,

4 NOTES AND MEMORANDA, Monthy ‘Stieroneeeteat

and until all these conditions are complied with, no title can appear
in the programmes.

Injecting Specimens for Microscopic Purposes.—Mr. T. Sharp
sends us the following queries, to which we shall be glad to have the
answer of our correspondents. Meanwhile, we append a brief reply.
Ist. How is the carmine fluid prepared? 2nd. When a subject is in-
jected, does it require any other preparation, such as hardening or
shrinking with anything ; and, if so, with what? 3rd. What is the
best method of slicing such substances as injected brain, lung, &e.—
Answers. (1) See Dr. Beale’s ‘How to Work with the Microscope.’
(2) We ourselves simply place the tissue in glycerine with a minute
proportion of carbolic acid. (3) Most persons prefer the razor. We
(Ep.) always use Valentin’s knife, and, from long practice, find it
most convenient.

Seeds of the Caryophyllaceze.—Those who are engaged in examin-
ation of seeds with the microscope, which is really a good field for
work, will find a paper of some interest “On the Seeds of the Clove-
Pink Family,” in the June number of ‘Science Gossip. It contains
about a dozen illustrations representing the seeds as magnified from
20 to 40 diameters.

Theonella or Dactylocalyx.—Two zoologists dispute about a
sponge. Which will “throw it up?” In the report of the meeting
of the Zoological Society, May 27th, we read the following :—A com-
munication was read from Dr. J.S. Bowerbank containing remarks on
the Sponge, lately described by Dr. Gray in the Society’s ‘ Proceed-
ings’ under the name of Theonella swinhoei, which Dr. Bowerbank
believed to be a species of Daciylocalyx, and identical with his
D. Pratiu.

‘Pond-life”” Photographed.— Mr. Slack is the historian of Pond-
life; but Mr. H. C. Richter is unquestionably its portrait painter.
We have before us a photograph taken from a drawing, and which is
a veritable “ study from life” of the organic world of the microscope.
It is an oval picture (about 7 inches by 5) which portrays the types
of the several forms of life seen under the microscope, and it is no less
a chef-d’euvre of artistic excellence than of skilled zoological repre-
sentation ; and while it depicts the various organisms with a minuteness
of detail which only a patient student can realize, and has placed each
element in its natural position, its tout-ensemble conveys a notion of
grace and truth. The subjoined list of the species included in this
picture gives some idea of its high scientific value :—

1. Stephanoceros Hichornii: Crown animalcule (Rotifer). 2. The
same ; retracted into its gelatinous tube. 3. Melicerta ringens (Rotifer).
4. The same; another view. 5. The same; partly retracted. 6. The
same; young with gelatinous tube. 7. Floscularia ornata (Rotifer).
8. The same; an old specimen. 9. The same; retracted into its
tube. 10. Rotifer vulgaris ; swimming freely. 11. The same; crawl-
ing along. 12. Dinocharis tetractis (Rotifer). 18. Petrodina patina
(Rotifer), 14. Cicistes longicornis (Davis), new species (Rotifer).
15. Macrobiotus Hufelandit. Water bears (Tardigrada). 16. Cantho-
camplus minutus (Entomostracan). 17. Cothurnia unberbis (Infusorial).

ea ie 1 lees NOTES AND MEMORANDA. 4)9)

18. Stentor Miillert (Infusorial). 19. The same; retracted into its
tube. 20. The same; detached and swimming freely. 21. Vorticella
nebulifera (Infusorial). 22. Volvox globator (Confervoide). 23. Huas-
trum didelta (Desmid). 24. Cosmarium tetraophthalmum (Desmid).
25. Pediastrum granulatum (Desmid). 26. Closteriwm lunula (Desmid).
27. Closterium moniliferum (Desmid). 28. Micrasterias denticulata
(Desmid). 29. Tabellaria ? (Diatom). 30. Spirogyra
(Confervoide). 31. Licmophora (Diatom). 32. Synedra
(Diatom). 33. Arcella vulgaris (Infusorial), 33*. Attached zoospore
of Conferva. 34. Stigeoclonium protensum (Confervoide). 35. Cos-
marium ? (Desmid). 36. Bulbocheete setigeria.

We would especially call attention to the Floscularia, which, when
looked at with a lens (and by the way all the figures bear magnifica-
tion), is exquisitely life-like. Mr. Richter has selected for his picture
the motto “ Maxime miranda in minimis,” which he certainly has done
much to establish. The photographs are sold by Messrs. Ross, of
Wigmore Street, and Messrs. Baker, of Holborn.

Microscopical Slides.—The American “Essex Institute” has
established a sort of manufactory of microscopical sections of all
kinds. Mr. Alpheus Hyatt, the author of a memoir of the Polyzoa, is
the secretary, and to him communications, objects, &c., should be
addressed. ‘The following is the prospectus published :—“ This estab-
lishment, founded by the liberal aid of citizens of Salem, Boston,
and New York, is now in successful operation. We have secured the
services of the well-known preparator, Mr. HE. Bicknell, and the com-
pleteness of our apparatus affords facilities for the production of a
style of slide inferior to none, whether of native or foreign manufac-
ture. Wewillsupply suites of Histological specimens for educational
purposes. Preparations of bone, teeth including the jaw, shells, corals,
spines and shells of Echini, or other hard tissues; also thin sections
of wood. Preparations of injured grain with its microscopial pests,
if specimens are sent or special orders given. Suites of specimens
suitable for the beginner in microscopy, or for the connoisseur seeking
amusement and instruction combined. Coarser Preparations.—Shells
and corals, fossil or recent, cut and polished. These show the colu-
mella of the shells, and the cells of the coral in the most effective
way for general study. Slides or preparations will be exchanged for
Specimens desired. Special attention given to preparations intended
for scientific investigation.

A Year-Book of American Entomology during the year 1868 is
about to be issued. It will be edited by Dr. A. 8. Packard, jun.,
whose excellent treatise on insects we some time since noticed in these
pages. Dr. J. L. Leconte will contribute a chapter on the Cleoptera ;
Mr. 8. H. Scudder, chapters on the Butterflies and Orthoptera; Baron
R. Osten Sacken, a chapter on the Diptera ; Mr. P. H. Uhler, a chapter
on the Hemiptera and Neuroptera; the Editor, chapters on the
Hymenoptera and Moths; and Dr. Hagan, an article on the False
Scorpions.

What tne Microscope has done——In a paper, written by M.
Léwenthal, and published in the Pharmaceutische Zertschrift fiir Russ-
land (April), an account is given of one of the most striking disco-

Cr

6 PROCEEDINGS OF SOCIETIES. uaa ay es

veries made by the aid of the microscope from the time of Leenwenhoek
to the present period.

Selenite Plates for the Microscope.—Some very excellent and
remarkably cheap selenite plates were recently shown us by Mr. W.
Bestall (4, Warrior Road, Camberwell New Road, 8.E.), who prepares
also a very simple and inexpensive form of polariscope, which those
interested in polariscopy would do well to examine for themselves.

PROCEEDINGS OF SOCIETIES.*

Royant Microscopican Socrmry.t

Kine’s CoLLeGE, June 9, 1868.

The President (Rev. J. B. Reade, M.A., F.R.S.), in the chair.

The minutes of the last meeting were read and confirmed.

A list of donations to the Society was then read; and Mr. Jabez
Hogg asked the Society to accept a new edition of his work on the
Microscope.

Mr. Hogg announced that he had reeeived from the widow of the
late Dr. W. B. Herapath, of Bristol, the inventor of the Herapathite,
a number of specimens of that crystal, which would be found very
useful for polarizing; and that any Fellow of the Society who
might wish to possess one, could obtain it of the Assistant-Seeretary
(Mr. Reeves), at a cost of about two shillings.

The President having intimated that Dr. Eulenstein had a matter
of business to bring before the meeting.

Dr. Eulenstein said it was probably well known that the late
Dr. Arnott possessed one of the most complete collections of Diatoms
in existence. That collection was about to be sold, and he had
arranged to purchase it. A full and particular list had been made of
the collection, and any gentleman who wished to obtain specimens
would be supplied with a catalogue on application, and the slides
selected would be delivered during the current summer.

The President said it would be very desirable for the Society to
possess such a collection as that to which Dr. Hulenstein had referred ;
and he presumed that if the Council undertook the responsibility of
purchasing sets, the Yellows would be willing to indemnify them for
the same.

He also thought it advisable to make some reference to a series of
papers on “The Construction of Object-glasses for the Microscope,”
of which Mr. F. H. Wenham was the author. These papers had
appeared in the Journal ostensibly as communications addressed to
the editor. They had, however, been published in that form as a

* Secretaries of Societies will greatly oblige us by writing out their reports
legibly—especially the technical terms—and by “underlining” words, such as
specific names, which must be printed in italics. They will thus ensure accuracy
and enhance the value of their proceedings.—Ep. M. M. J.

+ Report supplied by the Secretaries,

Monthly, Microscopical! PROCEEDINGS OF SOCIETIES. 57

matter of convenience, and the articles must be considered as com-
munications addressed to the Society. He (the President) hoped to
invite discussion upon the subject at a future period.

The President then proceeded to read a paper on “The Diatom
Prism and the True Form of Diatom Markings.” *

Mr. Wenham said: Some time since he had determined the
markings on some diatoms to be spherical, and that this discovery
had not been made by any special mode of illumination, but by the
examination of fractured specimens. In one of the fragments of
Quadratum a line of spherules had been detached like a row of beads.
At the extreme end a single spherule had separated sufficiently to
enable it to be examined in an isolated state. In another case a small
piece of the scale had been broken out and laid over close to the
opening, thus affording an immediate comparison of both sides of
the scale at the same time, and clearly proving the appearance to be
exactly similar on either. The diatoms in question are exceedingly
brittle; and if some of them are placed on a slide with water, and
thin glass-cover pressed hard down, and the whole left till dry, on
slightly moving the cover some of them will be broken, a portion
of the fragments adhering to each glass surface in various forms of
dissection. The President confirmed in a remarkable way the views
which he (Mr. Wenham) had entertained. An item of great value in
the mode of illumination used by the President was the length of the
prism, which threw a line of light from the condenser ; and he thought
that, by using a shorter prism of only one-fourth of the length, the
_ same effect would not be produced. The relief in which the object
was seen was very remarkable. In fact, it had all the appearance of
a solid body illuminated from above.

Mr. Browning said it was gratifying to know, that after having
bestowed so much labour on the attempt to resolve the markings on
diatoms, the President was able to exhibit the real facts by so simple
a method. |

(The President explained that he had been able to use a power as
low as the 2 inch).

Mr. Slack said it was very interesting to find that the deposition
of silica in the living diatom takes place under purely physical laws;
and the appearances which had been described as occurring on the
diatom-valves are exactly what can be produced in making artificial
diatoms by Max-Schultze’s process. The structure of the diatom-
valve shows that the so-called “vital forces” do not trouble them-
selves to interfere with the deposition of silica, according to chemical
and physical laws. He had never seen the markings on diatoms so well
and clearly shown as by the President's method, though he had long
distrusted any mode of displaying them that did not lead to the same
results,

Mr. Joseph Beck said it would be in the recollection of the Fel-
lows that his late brother made a photograph of a common tumbler,
the surface of which was covered with hemispherical elevations; and
that the photograph was made for the purpose of showing that the
hemispheres, under certain conditions, would present the appearance

* This valuable communication is published in the present Number.—Eb,

58 PROCEEDINGS OF SOCIETIES. [Mourns Ju 1 dose

of hexagonal structure, and that this appearance was due to the direc-
tion of the shadow in the one case producing the effect of elevations,
in the other of depressions. From this appearance his brother had
argued very strongly, in regard to the markings of some diatoms, that
they were caused by hemispherical nodules.

He (Mr. J. Beck) had examined some specimens of silex artificially
deposited, and amongst the more delicate fragments were pieces
exactly resembling Pleurosigma in structure; and on examining the
coarser fragments, which were similar to the more delicate ones in
structure, he found them to consist of hemispherical nodules deposited
at regular intervals on siliceous plates, showing clearly that an
appearance similar to that seen in the Pleurosigma could be produced
artificially, and affording a strong argument that the markings were
due to hemispherical nodules lying on a siliceous plate. At the same
time he did not consider the difficulty solved, for the markings on
some of the larger Diatomacezx, as Isthmia, Triceratium, Pinnularia,
&c., could not be accounted for in this way. The difficulties of
ascertaining real structure from the appearance presented might be
seen by taking a piece of zinc pierced with round holes and allowing
the sun-light to pass through it upon a sheet of paper; if held at
a certain distance there would be an image of round holes; but if the
paper were removed or brought closer to the plate, the appearance of
black hexagonal dots or of light hexagonal interspaces would be pro-
duced. He did not wish for one moment to undervalue the discovery
of the President ; but he thought more knowledge of the structure of
an object could be obtained by the use of a variety of modes of illu-
mination than by the observer restricting himself to the use of one only.

Dr. Eulenstein thought the structures observed in the larger
diatoms quite different from some of those of which the President
had spoken. As regards, however, the nature of the markings on
the Pleurosigma angulatum, he had, after examination with Powell’s
=ijth and Hartnack’s immersion lens, observed that the character of
the dots was hemispherical, a conclusion which Hartnack had dis-
puted. But he was not disposed to believe that the dots were com-
plete spheres of silex.

Mr. Hogg said he had, in conjunction with Mr. Mayall, paid much
attention to the subject in question, and he had come to the conclusion
that the markings in question were not merely dots. Hartnack was
now quite willing to admit that he had been in error with regard to
the diatom markings, and that they were really raised spherical dots.

Mr. Lobb said that for years he had considered the markings of
the Pleurosigma spherical, and indeed had never looked upon them as
anything else; and he was glad to find that his belief could be con-
firmed by the use of a low power, and at so little expense.

A vote of thanks to the President was then unanimously passed.

Mr. Hogg then read a paper “On the Results of Spectrum
Analysis.”

Mr. Hogg also informed the Fellows that Dr. Herapath, a short
time before his death, had been engaged in making investigations into
the spectra of the chlorophyll of vegetable substances, of which he
had examined about 250. He (Mr. Hogg) had hoped that these

eee ouy i ke PROCEEDINGS OF SOCIETIES. 59

researches would have led to a paper on the subject addressed to the
Society, but Dr. Herapath died before he was able to make any com-
munication to the Society. The only result of the investigations had
appeared in a letter which Dr. Herapath had written to a friend, and
which he (Mr. Hogg) had been permitted to read to the Fellows.

The letter was accordingly read, and copies of a lithograph
exhibiting the characteristic spectral bands of the various substances
were distributed among the Fellows, Mr. Hogg expressing his opinion
that Dr. Herapath had made a mistake with regard to the colours |
exhibited in the spectrum of the Laurestinus and Berberry.

Mr. Ray Lankester said that as he had paid some attention to the
spectroscope, he should like to make a few remarks. He was much
surprised on hearing Mr. Hogeg’s paper, seeing that it professed to
give the results of spectrum analysis, to find that he omitted all
reference to what were really the most important results obtained by
its means in biological science, namely, those that related to the
action of various gases and other reagents on the blood colouring-
matter Hemoglobin and Cruorin. Dr. Arthur Gamgee, Nawrocki,
Preyer, Hoppe-Seyler, and others, had worked most successfully in
this direction.

With regard to the late Dr. Herapath’s drawings of chlorophyll
bands, Mr. Lankester observed that he considered them as of little
value, since they were not really accurately measured, whilst a
method of preparation had been used which must be fallacious, and
which was the same as that which Mr. Hogg recommended. It is
useless to extract the chlorophyll from leaves at once by alcohol, they
must previously be soaked in water, to extract the vegetable acids
which are present in some leaves, and which greatly alter the absorp-
tion bands if allowed to act on the chlorophyll. Professor Stokes, of
Cambridge, who will in all probability soon publish a detailed account
of chlorophyll, by the use first of alcohol and then of bisulphide of
carbon, has succeeded in extracting two distinct green bodies from
ordinary plant chlorophyll. Mr. Lankester then pointed out the error
of Mr. Hogg’s assertion that the hemoglobin found in some house-
flies is present in their blood; it is simply in the intestinal canal,
having been taken in as food. This erroneous statement was the
more to be regretted as it tended to throw confusion on results which
Mr. Lankester had himself obtained and published in the ‘ Journal of
Anatomy’ two years since, and which he hopes to extend in a report
to the British Association this summer. He would particularly com-
mend this line of research to the Fellows of the Society. By the
use of the spectroscope, Mr. Lankester had found hemoglobin in the
vascular fluid of annelids of various species—in Chironomus larvee and
other larve, among insects, and in Planorbis corneus among molluscs.
His friend, Dr. Edouard Van Beneden, had just given him reason to
expect its discovery in certain remarkable parasitic crustaceans dis-
covered by that observer.

Besides this, with the spectroscope chlorophyll may be traced,
and should be looked for, in the animal kingdom. He had clearly
established its presence and published the fact in Spongilla fluviatilis,
in Hydra viridis, in Stentor, and in Mesostomum viridatum. This was

60 PROCEEDINGS OF SOCIETIES. — [Moniiy Microscopical
an exceedingly interesting branch of inquiry, which could only be
successfully prosecuted with the micro-spectroscope, since the quan-
tities of the coloured bodies were too small to admit of chemical
analysis. He protested very strongly against the notion ventured on
by Mr. Hogg, that thallium had anything to do with the chlorophyll
spectrum; indeed he hardly believed that he had heard Mr. Hogg
aright. As to the occurrence of copper in the Turacou’s feather, its
discovery had nothing whatever to do with the spectroscope, as Mr.

Hogg had stated, but was made before its spectrum was known;* and
' the spectrum, now that it is known, has nothing to suggest copper
about it. It is a very grave error to fall into to suppose that the
absorption spectra of coloured bodies are due to metallic ingredients,
they are simply caused by certain combinations of the organic elements
composing those bodies. He must also differ entirely from Mr. Hogg
as to the interest or value of the experiment made with a discased
crystalline lens. It is not possible to distinguish quantitatively by
means of the spectroscope at all (even Preyer’s recent proposition as
to estimation of hemoglobin being objectionable), and Mr. Lankester
believed that no one who knew the abundance of sodium in animal
tissues would credit Mr. Hoge’s assertion that he could distinguish an
increase of sodium in the cataract-lens by means of its flame-spectrum.

A vote of thanks was then passed to Mr. Hogg.

The President announced that Mr. Browning had prepared a short
description of a new form of micro-spectroscope which he had made,
and by which the most effective results could be obtained, at the very
low price of 22s. 6d.

Owing to the late hour at which the announcement was made, it
was ordered that the paper be taken as read.

A paper by Mr. Carruthers, “On the Structure of the Ulodendron,”
was taken as read, and will appear in the journal.

The President announced that the next meeting would be on the
13th of October, and intimated that during the month of August the
library would be closed as usual.

Donations to the Library, June 9, 1869 :—

From
Land and Water. Weekly wt Vaio y lew | Liat 2; pe mnie ieee aimarais
Scientific Opinion. Weekly .. ..0 .. 22) se bent eeeemeMnonOrs
Journal of the Society of Arts... 2.) .. «5 |. pep) SaneenmpsOeianue
The Student ae ue a eer ir MRA IME i A.) LeU.
The Canadian Journal PENA Ctigt ieee Deron EU Sh oo (?)
The Microscope. 7th Edition .. .. « Author.

John Armstrong Purefoy Colles, M.D., F.R.C.S.1L, was elected a
Fellow of the Society.
Water W. REeves,
Assist. Secretary.

* Professor Church, who discovered Turacine, does not seem to agree with
Mr. Lankester on this point. In his account of the matter in the ‘Student’
(vol. i., p. 165), he describes his experiments on Turacine with the spectroscope,
and states that the resemblance of its spectrum to that of cruorine induced him to
test for iron. He adds that, on applying potassic ferro-cyanide to a solution of
the ash of the pigment, “he was astonished that, instead of the deep blue of the
ferric-ferro cyanide, the rich purple brown precipitate of the cupric ferro-cyanide
was at once seen.”—Serc. R. M.S.

ey Na ooo, | PROCEEDINGS OF SOCIETIES. 61

Quexetr MicroscoPicaL CLUB.*

At the ordinary meeting of the club, held at University College,
May 28th, Arthur E. Durham, Esq., F.L.S., President, in the chair,—
the meeting was made special for the revision of the bye-laws, and the
various alterations proposed were read over and explained seriatim,
and were adopted nem. dis. At the conclusion of the special business
the minutes of the preceding meeting were read and confirmed, and
twenty new members were unanimously elected; a number of dona-
tions to the club were also announced, and thanks returned to the
respective donors. Mr. B. T. Lowne made an interesting communi-
cation relative to a specimen of a secretion from the stomach of a
flamingo, which he exhibited under the microscope, and which had

been obtained from a bird in the gardens of the Zoological Society.
* This secretion had recently been the subject of a discussion in ‘The
Field’ newspaper, and from its resemblance to blood, together with
the fact of its being made some use of in feeding the young, the
ancient fabled mystery of the Pelican in the Wilderness feeding its
young with blood drawn from its breast, here seemed to have met
with a solution. From an examination of specimens of this fluid, the
speaker was inclined to believe that it was not blood but a secretion,
though, from the circumstance of the birds being found here under
unnatural conditions, it might not be of a healthy character. Several
Instances were adduced of birds—the hornbills, bird’s-nest swallow,
&c.—being provided with similar secretions ; and the curious fact of
the passage of blood through membranes was referred to, some re-
markable instances being quoted in which, under the influence of great
excitement, it had been known to pass through the hides of Hippo-
potami and Rhinoceri. Mr. Lowne also drew attention to a very
beautiful preparation of the brain of the larva of a blow-fly, showing
clearly the imaginal [?]| discs described by Dr. Weissman in 1864. Mr.
W. W. Reeves made some remarks upon specimens of Noctiluca
miliaris, which he exhibited alive; they had been obtained off
Southend, and were amongst the results of a dredging excursion,
to which some of the members of the club had been invited by Mr.
Marshall Hall. Some further observations upon these creatures were
also made by Dr. Braithwaite, Mr. Arnold, and Mr. Breese. Mr.
Hislop called the attention of the members to a fine section of human
brain which he exhibited, and which had been prepared by Dr.
Dempsey. Mr. Johnson made a few observations upon the abun-
dance of Melicerta and Stephanoceros at Finchley, and indicated the
locality where they might be most readily obtained. The secretary
read certificates in favour of eleven gentlemen who had been proposed
for membership, and Mr. Curties placed upon the table two bottles
containing a supply of Conochilus for distribution amongst the
members. ‘The President announced that during the ensuing month
excursions would be made to Northfleet and Chiselhurst, also that
the annual dinner of the club would take place at Leatherhead on
June 23rd. The proceedings then terminated with a conversazione.

* Report supplied by Mr, R. I’. Lewis.

Monthly Mi ical
62 PROCEEDINGS OF SOCIETIES. Journal July ip seo,

Mancuester Crrcuntatinec Microscopic Capinet Socrery.*

Quarterly meeting, held 13th April at the Lower Mosley Street
Schools. Mr. R. Horne, President, in the chair.

The general business of the evening having been transacted, the
chairman called upon each member, from a list previously prepared
by the secretary, to exhibit the various slides of chemical crystals
they had prepared since last meeting,—the slides of each particular
crystal being shown under the several instruments and comments
made thereon, before a new crystal was introduced ; by which means
the best forms were easily perceived, and the different modes of pre-
paration and mounting were discussed whilst the objects were being
viewed, thereby making the meeting more instructive and enabling it
to pass off in a pleasant manner. The slides of santonine belonging
to Mr. Horne, and those of a salt of aniline, belonging to Mr. T.
Armstrong, were exceedingly pretty, and may justly be entitled the
_ gems of that class.

Resolved unanimously that the subject for examination at the
next meeting shall be “'The Structure of Ferns.” Hach member to
bring slides exhibiting the same, and what information he can gather
on the subject.

Liverpoot MicroscopicaL Socrety.t

The fourth ordinary meeting was held at the Royal Institution on
Tuesday, 6th April, Dr. Nevins, President, in the chair.

The secretary read a letter from Mr. T. C. White, M.R.C.S., on the
forms assumed by the crystals of hippuric acid at various temperatures.
Messrs. A. Kent and W. Chadburn were elected as ordinary members.

Mr. Newton exhibited a large number of slides sent by Mr. T.
Wheeler, of London. The paper for the evening was by Mr. J.
Newton, M.R.C.S.E., “On the Circulation in Plants and Animals.”
He dwelt on the fact that every living thing draws to itself its appro-
priate food, to supply materials for growth, to counteract the wear and
tear of its tissues, for reproduction, &c. Whence arises a need for
some special contrivance by which a complete circulation of the
nutrient fluid through every part may be effected. Commencing with
its simplest forms in the movement of the sap in plants, he traced it
through the lower forms of animal life, until in the jointed worms,
the annelida, we find a distinct circulatory system, consisting of two
main trunks, a dorsal and a ventral, by the contractions of which the
blood is sent through the smaller vessels. The various forms of
circulation in the insect world, in the gasteropoda, as snails, and in
reptiles, were next described. The necessity for the aération of the
blood in some form of lungs was dwelt on, whence arises the need
_ for a pulmonic as well as a systemic heart, to send the blood thus
purified through the body generally. It was shown that there are
really two hearts in all the higher animals, separated in some, but
blended apparently in many, as in man. The merits of Harvey, as

* Contributed by Mr. J. C. Hope, Hon. Sec., but not received by us till
June.—Ep. + Report sent too late for last Number.—Ep.

Monthly Microscopical] © PROCEEDINGS OF SOCIETIES. 63

the great discoverer of the circulation of the blood, were dwelt on,
and also of Malpighi, who first demonstrated it to the naked eye by
means of the microscope. The lecture was illustrated by coloured
diagrams, dissections, and living objects.

The fifth ordinary meeting was held at the Royal Institution, on
Tuesday, 4th May, Rev. W. Banister, B.A., Vice-President, in the
chair.

Brisrot Microscopican Socrery.
May 27th, 1869. Mr. W. W. Stoddart, F.G.S., F.C.S., President,

in the chair.—The minutes of the preceding meeting having been
read and confirmed, and some other business discussed, Mr. W. J.
Fedden, Vice-President of the Society, read a paper entitled “A
Gleaning from the Float.” The paper was a descriptive account of
various organisms found by the author in the floating harbour at
Bristol. He said it must not, however, be considered in any way
as an account of the zoology and botany of the harbour, as he had
not by any means worked out the subject so completely as he in-
tended to do, and that, therefore, his present paper must be considered
merely an instalment of more to come.

The following is a list of the various animals and plants mentioned
by Mr. Fedden :—

Crustacea :—Cyclops quadricornis, Talitrus,

Rotifera :—Rotifer vulgaris, Brachionus,

Helminthozoa :—Anguillula fluviatilis.

Infusoria :—Huplotes charon, Urostyla grandis, Stylonichia mylitus,
Amphileptus anser, Amphileptus fasciola, Cothurnia imperbis, Cothurnia
Jloscularia, Chilodon cucullulus, Epystilis digitalis, Carchesium polipinum,
Vorticella patellina, Vorticella nebulifera, Vorticella convallaria, Stentor
polymorpha, Stentor Mulleri.

Diatomacez :—Diatom tenue, Diatom elongatum, Diatom mesoleptum,
Synedra tenuis, Synedra angustata, Surirella ovata, Bacillaria paradoxa,
Melosira varians, Schizonema, — sp. ?

The author stated he had as yet been able to find scarcely any Des-
midiz or Algz, and would therefore reserve them for a future occasion.

sp. ?
— sp.?

BrigHTon AND Sussex Naturat History Soctery.

June 10, Mr. Sewell, Vice-President, in the chair—A paper was
read by Mr. J. Robertson, entitled “A Narrative of a Recent Visit to
the Volcano on Barren Island, near the Andaman Islands,” which,
though a very interesting contribution to science, contained nothing
in relation to microscopical or histological research.

Marpstone AND Min-Kent Narurat History Socrery.*

The first general meeting of the Maidstone and Mid-Kent Natural
History Society was held on Tuesday afternoon (May 18th) in the

* The Secretary would much oblige us by in future forwarding a brief abstract
of the meetings. The task of employing the scissors on a long newspaper report
which has on this occasion fallen to our lot, is not a pleasant one, and it takes up
much time.— Ed. M. M. J.

64 BIBLIOGRAPHY. ea eg

Library at Chillington House, which had been kindly lent by the
Museum Committee. The Society has only been recently established.
It holds its meetings at 86, Week Street. The President is the Rev.
J.G. Wood, M.A., F.L.S.; the Vice-Presidents, Dr. Monckton, A.
Randall, Hsq., Rev. D. D. Stewart, C. Roach Smith, Esq.; the ‘Trea-
surer, Mr. H. Bensted ; the Corresponding Secretary, the Rev. H. W.
Dearden, M.A.; and the Local Secretary, Mr. J. H. Martin.

The chair was occupied by the President, Mr. Wood, and there
was a good attendance of members and visitors.

The President gave a. very interesting address. Mr. Carruthers
then delivered an important lecture on “Some Fossil Cicads.”

In the evening a conversazione took place, when some bota-
nical and entomological specimens were exhibited, with a number
of microscopes and a few scientific instruments. The circulation of
blood in a frog’s foot was illustrated, by means of the microscope, by
Mr. Martin, one of the hon. secretaries.

BIBLIOGRAPHY.

Etudes photographiques sur le systéme nerveux de Vhomme et de
quelques Animaux supérieurs d’aprés les coupes de tissu nerveux con-
gélé; par Pierre Rudanovski. Paris.

Voyage scientifique autour de VAquarium; par M. Poret.
Havre.

Passage des Leucocytes a travers les membranes organiques; par
M. L. Lortet. Lyon.

Die Motorischen Endplatten der quergestreiften Muskelfasern
von Dr. W. Krause. Hannover.

Kritische mikroskopisch — mineralogische Studien von Prof.
Fischer. Freiburg.

Mycologia Europcea, von Herren, W. Gonnermann und L.
Rabenhorst.

School and Field Botany. By Professor Asa Gray. New York.
This work consists of the Field, Forest, and Garden Botany, and the
Lessons in Botany, bound together in one volume. _

On the Origin of Species by means of Natural Selection. By
Charles Darwin, M.A., F.R.S. 5th edition, with additions. London.

O

TheMonthlyMicroscopical Journal. Aug 1.1869.

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Stems from Coal-Measures.

THE

MONTHLY MICROSCOPICAL JOURNAL.

AUGUST 1, 1869.

4 o= =

I.—On a Simple Form of Micro-spectroscope.
By Joun Brownine, F.R.AS.

(Read before the Royat Microscopican Society, June 9, 1869.)

THE instrument I have now to describe is substantially the same
in its optical arrangements as that I had the honour of perfecting
with Mr. Sorby some time since. As this instrument has been
described in a paper I gave at the same time to the Society, I shall
give but a very brief description of it on the present occasion.

The instrument consists essen- ,
tially of asht A, the width of which
is adjustable by the screw D. An
achromatic lens B, which focusses
on the slit by sliding the tube E in
the outer tube FF. A compound
direct-vision prism C containing
five prisms, and a small reflecting-
prism P placed outside the slit A.
This prism is for the purpose of
throwing a second spectrum into
the field of view for the purpose of -
comparison. The spectroscope is
attached to the microscope by the
adapter G, which fits into the drawer-tube of the microscope.

The best method of using this spectroscope is to first find the
object in the microscope, and bring it to the centre of the field by
means of an ordinary microscopic eye-piece. Then open the jaws
of the slit by unscrewing the screw D. Remove the ordinary eye-
piece from the microscope, and substitute the spectroscope in its
place. The object should now show a confused spectrum through
the jaws of the sht. On closing the slit and focussing carefully by
means of the sliding-tube KE, the absorption bands, if there be any
in the spectrum, will become plainly visible.

I have been induced to arrange this simple and economical form

VoL. IL. F

66 On the Structure and Affinities of [Monthly Microscopical

Journal, Aug. 1, 1869.

of micro-spectroscope at the earnest request of our excellent secretary,
Mr. Hogg, who is of opinion that the price of the instrument pre-
viously has prevented its adoption. |

II.—On the Structure and Affinities of some Exogenous Stems
from the Coal-measures. By W. C. Witttamson, F.BS.,
Professor of Natural History in Owen’s College, Manchester.

THE generic term Dadoxylon, orginally introduéed by Endlicher,
has long been used in a vague manner by phytologists. It has
been applied to a large number of woody stems, common in the
Coal-measures, very few of which have any claim to rank in the
genus.. As defined by Endlicher and Brongniart, the genus is
characterized by “les rayons médullaires étroits, simples composés
d’une seule lame de tissu cellulaire;” and further, it has ‘les
ponctuations des fibres ligneuses disposées en plusieurs séries alter-
nantes entre elles, et prenant par pression la forme d’aréoles
hexagonales.” *

In 1851 I described the structure of some forms of Sternbergie,t
and pointed out the apparently coniferous character of the woody
zone surrounding the pith. I demonstrated the existence of rows
of discs on the woody fibre arranged as in the living conifers; and
concluded that the plants under consideration were true examples
of Endlicher’s genus Dadoxylon. Since the publication of that
memoir, numerous specimens of woody stems have been found,

EXPLANATION OF PLATE XxX.

Fic. 1.—Vertical section of two fibres of Dadoxylon, from Coalbrook Dale.
» 2-—Tangential aspects of the same.
», 3-—Vertical section of part of a reticulated vessel of Dictyoxylon Oldhamium.
Mr. Butterworth’s cabinet. ' es
» 4.—Tangential section of two vessels of the same, separated by a medullary
ray.
» 5.—Varieties of discs from the vessels of Cycas revoluta.
» 6.—A vessel from the same.
a, pitted tissue.
b. glandular discs.
» 7—Fragment of a stem of Dictyoxylon, reduced one-half.
5, 8.—Reticulated fibre from a tangential section of Araucaria imbricata.
,, 9.—Fibre froma tangential section of Thuja Donniana.
,, 10.—Part of a scalariform vessel from the inner cylinder of a Lepidodendroid
lant.
5s Teaver section of a Dictyoxylon, showing the Sternbergian pith. Mr.
Butterworth’s Cabinet.
5, 12.—Portion of Fig. 10 further magnified.

* ‘Tableau des Genres de Végétaux Fossiles,’ par Adolphe Brongniart, p. 76.
+ ‘Transactions of the Literary and Philosophical Society of Manchester.’

Monthly Microscors'| °. some Exogenous Stems. — 67
transverse sections of which exhibit a structure identical with that
of living conifers ; but longitudinal sections show that the vessels
or fibres are altogether different from the glandular or discigerous
type. Instead of bearing rows of discs, and only on the surfaces of
the vessels parallel with the medullary rays, their entire walls are
covered with reticulations formed by the deposition of lignine zn the
interior of the vessels, All the specimens which have been latterly
collected have been of this character; hence some of the most
experienced phytologists came to the double conclusion that whilst
the plants in question were true Dadoxylons, both Endlicher and
myself had mistaken the internal reticulations of the fibres for the
lenticular discs of true glandular fibre. Had this explanation been
correct, we should have been left without any true coniferous wood
in the Coal-measures. But it is not correct, as I shall now proceed
to demonstrate.

Fie. 1 represents two fibres from my now celebrated specimen
from Coalbrook Dale. The surfaces shown are those parallel to the
medullary rays, and it will be seen that these surfaces are entorely
covered in every fibre with discoid areolations. In some instances
(Fig. 1, a) there are two vertical rows of these areole: the mutual
pressure of their inner contiguous margins of which gives them
a somewhat hexagonal form ; but in other examples, as at Fig. 1, a,
there is a distinct interval between the discs. In Fig. 1, 6, we have
three such vertical rows: the centre row, especially, having the
hexagonal form to which M. Brongniart refers in his description of
Dadoxylon. ‘The only point in which these structures differ from
the similar ones of living Araucarian conifers is the absence of the
central dot in each disc. Of this I have never been able to detect a
trace.

Fig. 2 represents two similar fibres as they appear in a tan-
gential section of the stem. ‘The surfaces (2, a) are here entirely
smooth, being free alike from discs and reticulations. But between
the contiguous fibres (2, b) we have a headed structure revealing the
discs of Fig. 1, seen in section. The fibre-walls (Fig. 2,¢) are very
distinct, and afford the clearest proof that the discs are external to
the fibre, as in recent conifers. ‘There cannot be the slightest room
for doubting that, whether the fructification of the tree was or was
not coniferous, we have here a modification of true glandular or
discigerous pleurenchyma. But if we turn to the more abundant
examples of the so-called Dadoxylons, we shall find an altogether
different structure.

Fig. 3 represents a fibre of the plant which Mr. Binney has
designated Dadoxylon Oldhamium, and which, in the specimen
figured, exhibits* the most magnificent instance of reticulated

* This specimen is from the rich cabinet of Mr. Butterworth, of High Cromp-
ton, near Oldham.
F 2

68 On the Structure and Affinities of [Monthly Microscopical
fibre with which I am acquainted. The fibres are unusually large,
having constantly a diameter of from 335 to z}y of an inch. The
reticulations cover the surface of the fibre, each areola being from
teoo tO sooo Of an inch in diameter.

Fig. 4 represents part of a tangential section exhibiting the
surfaces of two fibres parallel to the exterior of the plant. The
fibres are separated by one of the large medullary rays, with its
multiplied vertical rows of cells, and which constitute one of the
striking features of this remarkable species. This section demon-
strates what I have already affirmed, vez. that the reticulations
cover equally the entire circumference of the interior of the tube,
and are not confined, like the areola of coniferous fibres, to its
lateral surfaces. These two figures represent reticulated fibres as
seen in several distinct plants found in the Coal-measures. Whether
these prove to be different species of one genus, or whether they
will require more than one genus for their reception, remains to be
seen. But certainly none of them can be regarded as Dadoxylons,
since they belong to an altogether different type of structure. In
the general arrangement of their tissues, whether of pith, wood, or
bark, they correspond very closely with the true conifera, but we
have no evidence that they were conifers.

Since these plants with reticulated fibres can no longer be
recognized as Dadoxylons, they must either be assigned to some
other existing genus, or have a new one instituted for their re-
ception. The only existing genera which approach them are
Paleoxylon and Pissadendron—the first of which was founded by
Witham, and the last by Brongniart, for the reception of some
of Witham’s plants. All these are described by Brongniart as pos-
sessing true coniferous fibres, which, if correct, would exclude the
specimens under consideration. It is possible that some of the
former may belong to reticulated types—especially Palaeeoxylon—
but, since they are not so defined by the founder of the genera,
they must for the present be left amongst the conifers, though they
may be doubtful ones. 3

It appears necessary, therefore, to establish a new genus for all
the plants whose woody cylinders consist of reticulated fibres ;
and the name of Dictyoxylon appears an appropriate one for it.
I should propose for the present to include in this genus all the
reticulated types—whether their médullary rays consist of one or
of several vertical series of cells. At some future time their further
separation into two or more genera may be requisite.

I have already called attention to the fact that the hexagonal
and almost circular discs of the fibres of Dadoxylon (Fig. 1)
exhibit a plane surface, the central dot common in recent conifers
being absent. The absence of this dot led the late Robert Brown,
some years ago, to reject my conclusion, that the fibres in question

purial, Aug 1, 1869. some Exogenous Stems. 69

were of the coniferous type—neither of us at that time being
aware of the demonstration that the tangential section would afford.
I think I now see my way to an explanation of the absence of
the dot, The question has a sufficiently important bearing upon the
hypothesis of development of one tissue out of another, and, pard
passu, of one plant out of another, to give it importance.

In studying the microscopic tissues of the Cycadex, I have for
some time been convinced that the discigerous vessels in Cycas re-
voluta, usually supposed to be of a coniferous type, were in some
measure modifications of scalariform tissue. I have now found nume-
rous vessels from the above plant, which renders the fact certain,
since they exhibit discigerous tissue at one end of the vessel, whilst
it becomes scalariform at the other. My views on this poimt, when
promulgated in private correspondence with some botanical friends,
were at once rejected by them; but there is no reason for ques-
tioning their correctness. I was not aware, however, when I came
to this conclusion, that I had been anticipated by the late Mr. Don,
in a paper which he read before the Linnean Society in 1840.
The question is of some importance, since it affects the possibility
of a glandular coniferous fibre being developed out of a reticulated
one.

There exists amongst geologists some misconception respecting
the true nature of a glandular disc, which consists of two very
distinct elements, viz. the circular or hexagonal areola and the
central dot. The outlines of the former vary chiefly according to
the mutual pressure to which they are subjected. The latter
variously appear as a small circular dot (Fig. 5, a), an oblong one
(Fig 5, b), which is sometimes so linear as to stretch across a great
part of the disc (Fig. 5,¢); and occasionally they assume a regular
(Fig. 5, d) or irregular crucial shape (Fig. 6, b). The simple dot is
due to a deficiency of the lignine lining the rest of the intercor of
the vessel, and is in no respect different from the pits of a pitted
or porous vessel. But the circular disc or areola is external to the
tube, consisting of a lenticular depression on the exterior of the wall
of the fibre. That there is some connection between these two
objects, when first formed, is obvious, from the constant presence of
the dot in the centre of the areola, wherever the latter exists in
recent plants. ‘Thus the coniferous disc consists of two elements,
one of which is internal to the primary wall of the vessel, whilst
the other is external to it. The former may exist without the
latter, as is the case in all porous or pitted vessels; but, as I have
just observed, the latter never exists without the former, in the
fibres of recent stems. Fig. 6 represents part of a scalariform vessel
from Cycas revoluta, where the ligneous deposit has been so extended,
that the oblique, transverse, thin spaces separating the bars of
lignine, are reduced to mere oblong “ pits” (Fig. 6, a), but where

70 On the Structure and Affinities of [Monthly Microscopical

the oblique parallelism of the original type of structure is still dis-
tinctly preserved. In this vessel a few of the pits are surrounded by
an areola (Fig. 6, b), forming a true coniferous disc. In this indi-
vidual fibre the addition of the areola is accompanied by a corre-
sponding addition to the central dot, giving it an irregular crucial
form, which does not exist in the “ pits” that are not so furnished ;
demonstrating that the addition to the oblong dot converting it
into a crucial one is external rather than an internal—such additions,
however, are exceptional, though not rare. What causes determine
the selection of special dots for areolation is uncertain; but we
have here a manifest illustration of the process by which a spiral or
scalariform vessel may be gradually transmitted into a glandular
or discigerous one, and of the way in which the “pits” of the
former structure regulate the positions of the discs of the latter.

It appears clear that in my Dadoxylon (Figs. 1 and 2) we
have the outer lenticular disc, but not the internal deposits, con-
verting the fibre into a pitted tissue. Hence the absence of the
central dot in each areola, affording a new instance of the differ-
ences existing in the combinations of the elementary tissues in
fossil as compared with recent plants, to which I have elsewhere
called attention. In the stems of all the true conifers the discs are
confined to the lateral surfaces of the fibres, parallel with the
medullary rays—an arrangement to which those of Dadoxylon are
no exception. I have observed that, in every recent conifer which
I have studied, the “ pits” opposite the discs (which are often con-
verted into pores by the absorption of the wall of the vessel), also
exist opposite each medullary ray, and there only, indicating some
correspondence in the functions of the discs and the rays.

Whilst Dadoxylon thus appears to furnish the lenticular disc
or external element of the coniferous fibre, I think we may regard
Dictyoxylon as supplying a modification of the internal deposits,
and thus possessing some relationship to the conifers. That the
general aspect of the wood has been coniferous is shown by Fig. 7,
which represents a specimen in my cabinet from the Lancashire
Coal-measures. It is a portion of a large stem through which
there passes a branch or “knot;” the undulations of the woody
layers immediately below the branch too closely resemble those
of a roughly-split pine-log to be overlooked. In the centre of the
branch there appears a section of a rather large pith. :

In estimating the true significance of the reticulated deposits
of lignine in Dictyoxylon, we must recall the varied .character of
these internal deposits in recent conifers. They assume the sim-
plest form in the common deal and other allied plants, where a
continuous layer of lignine lines the tube, being wanting only, as
already pointed out, opposite the glandular discs. In addition to
this, in the common yew a second and more internal deposit exists,

Monthly Mi ical
Honth’y Microseorical] some Exogenous Stems. | rat

in the form of a delicate spiral thread winding round the tube at
wide intervals. In many of the Thujas and other Cupressine, an
immense number of such threads line the previously thickened
tube, and, running in opposite directions, cover its interior with a
fine network. Fig. 9 represents a fibre of this kind from Thuja
Donniana.* <A further advance is shown in an example of
Araucaria imbricata which I examined some years ago, and of
which I fortunately preserved a section, since I have never since
been able to detect the same structure in other plants of this
species. Many of the fibres exhibit the appearance represented
in Fig. 8, a reticular deposit of translucent lignine lining their
interior, closely corresponding with that of Dictyoxylon. This
fact appears to me to have some significance in relation to the
affinities of the Dictyoxylons; since it is the only instance in which
I have detected a similar structure in a living conifer. Why I
fail to find the same structure in other examples of this species I
cannot discover. Having made the preparation myself, I know it
to belong to the plant in question; besides which, its other fea-
tures are identical with those of corresponding sections of this
Araucaria which I have made more recently. Be the cause of
this anomaly what it may, the specimen remains to demonstrate
that, under some conditions, the ligneous deposits of the conifera
assume a reticulate form. All the known modifications of reticulate
vessels were long ago shown by Meyen to be modifications of the
ordinary spiral vessels—a fact of which the fossil-plants of the
Coal-measures afford ample proof. Figs. 10 and 11 represent a
portion of a scalariform vessel from a Lepidodendroid plant from
the Coal-measures, probably a Lomatophloros.t We here have a
condition intermediate between the simple scalariform vessel and
the reticulate one of Dictyoxylon. In this example there is a pecu-
liar feature which I have observed both in young twigs and in old
stems of the plant, viz. a number of delicate vertical lines of lignine,
usually simple, less frequently branched, connecting together the
contiguous transverse bars of the vessel. Fig. 12 represents a few
of these vertical bands further enlarged. I am not aware that this
very curious modification of the scalariform vessel has been hitherto
noticed.

The examples quoted suffice to show how variable are the
modifications of the elementary spiral fibre amongst living conifers,
and the reticulations of the vessels of Dadoxylon present but one
more variation of the same primary type. From this we may
conclude that Dadoxylon and Dictyoxylon separately possess the

* IT have found the same structure in some fossil stems from the Cretaceous
beds of Missouri.

+ This plant is evidently identical with that described by Mr. Binney in the
‘Phil. Trans.,’ under the name of Sigillaria vascularis. I am convinced that it
was not a Sigillaria, but a form allied to Lepidodendron, as stated above.

72 On the Structure of Exogenous Stems, [Monthly Microscapical

two elements of external discs and internal deposits which, when
combined, constitute the coniferous vessel. The Darwinian would
find no difficulty m concluding that the pollen of one of these
plants might fertilize the ovules of the other, and thus produce, at
some later period, structures in which there combined the two
elements that are severed in the vessels of Dadoxylon and Dicty-
oxylon.

It is evident that both the above genera possessed in some
instances, if not in all, piths of the Sternbergian type. Fig. 11
represents a beautiful vertical section of a Dictyoxylon from Mr.
Butterworth’s cabinet—in which the Sternbergian pith is very
well displayed—the discoid laminze extending completely across the
medullary cavity. This specimen is also remarkable for the regu-
larity of the lamime, as well as for the peculiar thickened aspect
their section exhibits near the walls of the medullary space.

When we consider how abundant these large exogens—espe-
cially the Dictyoxylons—are in the Coal-measures, it becomes
remarkable that we have hitherto been unable to identify either
their foliage or their fructification. I cannot believe that the latter
assumed the form of recent cones, or such would have been common
amongst other Carboniferous fossils, because of the readiness with
which such structures are preserved. This is shown by the
abundance of Lepidostrobi in these beds. It seems to me not
improbable that Trigonocarpon may have constituted the fruit of
one of these genera. Dr. Hooker has already expressed his convic-
tion that it was the fruit of a conifer allied to the modern Salis-
buria: from its abundance in many districts, it must have belonged
to one of the more common trees of the Carboniferous period. This
would point to Dictyoxylon, which is abundant in the Lancashire
districts, where Trigonocarpons are common, as constituting the
parent stem from which the latter had fallen.

T would observe, in conclusion, that I have very little confidence
in any determinations respecting fossil plants, excepting such as are
based upon internal structure: all the modern classifications of
living plants rest upon this basis, and it is the only safe guide
amongst fossil ones. Of course its indications require to be
checked by considerations of external form ; but the former must be
primary, and the latter but secondary aids. We rely upon the
former when the latter is not to be obtained, but only then.

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Battledore Scales

Monthly Microscopical! Qn the Battledore Scales of Butterflies. vo

III.—On the Battledore Scales of Butterflies.

By Joun Watson, Esq.
Puates XXI., XXII., anp XXIII.

Some time since I communicated a series of papers on this subject to
the ‘ Proceedings of the Literary and Philosophical Society of Man-
chester ;’ but as it would seem that the subject has been noticed by
so few other observers, I am induced to recur to it in the pages of
the ‘ Monthly Microscopical Journal.’

The scales of lepidopterous insects have long been subjects of
microscopical examination ; but it may be questioned whether suffi-
cient notice has hitherto been taken of their peculiarities, with a
view to the determination of the genera, species, and affinities of the
insects, or of their systematic functions.

The ordinary scales are more or less oval, showing from two to
five or more dentations at the broader end, and having a short, stiff,
pointed peduncle at the other extremity, by which they are attached
to the membrane of the wings. These scales are flat, like those of
fish, and show striated markings. Referring to them in his ‘ Intro-
duction to the Classification of Insects,’ Westwood says, “ Lyonnet
has filled several quarto plates with representations of these scales,
varying to almost every form, taken from the wings and body of the
Goat Moth; so that the suggestion of a writer that the forms of
these scales might be used for specific characters is entitled to no
weight.” (He likewise refers to a paper upon the same subject by
a French author, presently to be noticed.) It appears probable
that two or more different kinds of scales, serving distinct and
separate offices, are to be found in lepidopterous insects; and this
difference of function has not before been suggested.

In some genera of the diurnal Lepidoptera, besides the ordinary
scales, some peculiar forms exist ; and it is to these attention is now to
be drawn, especially to those found in the genus Preris and its con-
geners. Hxamination with the microscope shows that these scales
are not flat, like the others, but cylindrical, or bellows-shaped, and
hollow; they are attached to the wings by a bulb, at the end of a thin
elastic peduncle differing in length in different species. The bulb also
varies in size and shape ; and there is a hole or indentation to receive
it in the membrane of the wing, larger than that for the ordinary
scale; and the whole apparatus has the appearance of a ball-and-
socket joint, allowing considerable facility for motion or play. The
scales are fixed to the wings at the broader instead of the narrower
extremity, and there they are furnished with a fringe of cilia or
hairs. ‘The scales are placed on the upper surface of the wings,
principally on the superior ones, with their tips projecting between
the common scales ; they are easily detached, and in removing them

: Monthly Mi ical
14 ait On the Battledore Autre Maecae

the bulb is very liable to be broken off; they are much more nume-
rous on some species than on others, and their number varies con-
siderably even on individuals of the same species, especially at dif-
ferent periods of existence. The males alone possess them; none
are ever found upon the females. They have been called “ plumules”
by some authors; and those of Pieris Brassice, P. hapx, and
P. Napi (our common white garden Butterflies), are well known to
microscopists, and were formerly called test-objects.

In the ‘Annales des Sciences’ for February, 1835, there is an
interesting article on the organization of the scales of Lepidoptera,
by M. Bernard Deschamps. It is principally devoted to the con-
sideration of the structure of the scales, as composed of several
lamellee or membranes; of the mode in which they are affixed to the
wings; and of the place in which the colouring matter is deposited.
He also refers to these plumules, and gives figures of a few of them:
he does not suggest any peculiar use for them, but draws attention
to the fact that the males alone possess them, and that they have
some general resemblance, with certain specific differences. He
examined and figured seven species of the Pieridze, to which family
I am about to allude. My friend Mr. Sidebotham has most kindly
and laboriously drawn the plumules of about one hundred species of
Pieridze observed by me, Te few if any of which have been figured
before.

According to the modern arr angement of Doubleday, Westwood,
and Hewitson, the family “Pieridee” consists of sixteen genera, and
in seven of them, viz. Huterpe, Pieris, Anthocharis, Idmais, Thestias,
Hebomoia, and ‘Eronia, I have discovered plumules.* There are
several distinct types of plumules, generally more or less running
into one another; but each species possesses its own peculiarity,
with diversity sufficient for identification, while in each individual of
the same species there is always the same form of plumule. These,
therefore, must afford to the scientific entomologist a valuable test
in the determination of closely allied species, and it is probable that
they may serve to form congenial natural groups and subdivisions
in some of the genera.

It is remarkable that the peculiar and well-known plumule of
Pieris Rapx should prevail, in a generic and very similar form,
also in P. Napi, P. Cruciferarum, and P. Gliciria (the first two
European, the third North American, and the fourth Chinese).
These insects are of close affinity in other respects ; and in other
instances congeniality of plumule is found in nearly allied insects.

The most remarkable and beautiful form of plumule, now for
the first time observed, as far as is known to the writer or others
to whom it has been shown, is that found on Pueris Agathina

* 'The examination extended over about 300 species ; and I found pms: in
all the male specimens, with three exceptions.

ge eee Scales of Butterflies. 75

and P. Chloris, two West African Butterflies ; and no approach to
this form has been discovered on any others. The study of the
actual objects with the binocular microscope and high powers will
be well rewarded, and give abundant cause for speculation as to the
absolute form of the plumules. They appear to be hollow mem-
branous bags of a cylindrical or triangular shape, bound round by
longitudinal ribs, which are curved inwardly, forming a contraction
at about one-half or one-third of their length, where they are
drawn in as by a cord. At the base, the ribs are inflexed towards
the peduncle and bulb, to which they seem attached by the mem-
brane. The large double-lobed transparent bulb, besides acting
as a ball-and-socket joint, seems to serve as a valve to close the bag.
Above the contraction, the ribs are continued with a curvature
similar to the lower portion, and terminate in extremely fine and
delicate points. In different specimens these approach more or
less closely, and they appear to be free at the upper extremity,
with a power of contraction or closing to protect the interior of the
bag from the entrance of injurious matter. Their appearance is
very much like that of the ciliated tentacula of the Stephanoceros
or peristomes of some of the Mosses. The length of the bag is
about 1-300th of an inch, without the peduncle and bulb, which,
when fully drawn out, extend about 1-800th of an inch further
beyond the point of attachment. ‘

Next comes the interesting question concerning the function of
these plumules in the economy of the insects, and the purpose they
serve beyond that of the ordinary scales, which seem to act as the
feathers of birds, in guarding the insects from wet, and supporting
them in their flight—unless, indeed, they are not more nearly
allied to the scales of fish. Reaumur and some other entomologists
have supposed that the common scales, in addition to these ends,
supply the trachez in the nervures of the wings with air, and that
the striz show the channels or air-passages ; but after close exami-
nation of them with high powers, no external openings have been
found fitting them for this purpose. The plumules, on the con-
trary, appear admirably adapted for air-vessels: they are hollow,
and can be inflated like balloons, and have a tuft of cilia at the
summit, which, by constant oscillation, may prevent hurtful sub-
stances from entrance, just as the cilia in the spiracles of many
insects act. ‘Through the bulb, which is valve-like shaped, being
divided into two lobes, there may be communication with the
trachee. The plumules may thus perform a double function, con-
ducting a supply of air to the nervures of the wings, and, when
inflated, adding considerably to the buoyancy of the insect. Besides,
from the manner in which they are placed, partly between and
partly under the ordinary scales, the latter must be raised when
the former are inflated; and when not in use, they probably lie

76 On the Battledore [Mente
flat, like empty bags, under the superincumbent scales. By this
supposition, as regards the functions of these plumules, we may
account for the superior strength and power of flight which the
males possess over the females.

Here, then, is a field open for great microscopical research—a
field which promises variety of interest the further it is pursued.
New forms of scales will probably be discovered in many genera.
hitherto unexamined ; the attention should not, however, be directed
solely to the observation of these plumules, as all the forms of
scales are worthy of careful study.

In the following families I have found no plunmiles, viz. Papi-
lionidee, Acreeide, Morphide, Brassolide, Eurytelide, Libytheide,
and Hesperidee. In the Danaide I have found them only in the
genus Huplea. In the Heliconide only in the genus Heliconia,
unless Huezdes is to be considered as belonging to this family, and
not to the Nymphalidz, which position is justified by the form of
the plumule. In the Nymphalide I have found them in several
genera, principally of the Argynnis group ; and notably in Athyma,
but not in Neptis. In the Satyride in several genera, and the
well known scale of Epinephele Janira is a good type of the generic
form.

And now passing to the Lycenidz, I beg to refer to the battle-
dore scales (so called) which are represented in the accompanying
plates. ‘They seem to be intended to serve the same office as the
plumules in other families, whatever that may be. They exhibit
similar generic and specific alliances and differences, and answer
the same purpose of identification of species.

They are most beautiful microscopic objects, and interesting in
a physiological sense, displaying how variously and marvellously
creative power has worked in these minute organisms, always with
the same end in view.

The especial function of the plumules of the Pieride has been
suggested by me to be. that of air-vessels, giving buoyancy to the
insects; and these Lycena scales, by their balloon shape, are emi-
nently fitted for this service, and even in a greater degree render
it probable that certain Lepidoptera possess at least two kinds of
scales, performing different offices in the economy of the insects.
These plumules are attached to the wings by an apparently hollow
peduncle. They show striz-like ribs, suitable for binding, strength-
ening, and distending or contracting ‘their balloon-like forms ; ; these
ribs are more or less beaded or articulated, by which different scales
are bound or bent in various ways. The end opposite to that of
insertion is closed or covered with apparently ciliary apparatus.
And they lie in rows between and under the ordinary scales, which
may therefore be elevated or depressed at the pleasure of the insects
by the regulated inflation of the plumules. They differ in separate
species in every conceivable way—in form, in the number and

nthly MI ical ; ) |
spournaly ANE 1, 1869, Scales of Butterflies. 77

articulation of the ribs, in transparency, im size, and in the length
and shape of the peduncle; and among them are found some very
anomalous forms, as in the plumules of the Pieride. In that
family, Preris Agathina possesses an abnormal and unique form ;
and so in the Lycenide, Lycena betica resembles it in this
peculiarity.

And as in the Pieride, so in the Lyceenide, it is only on the
males that these scales are found; it is probable that this mark of
virility may indicate the comparative vigour or age of the insects. On
some individuals of the same species they are much more abundant
than on others; and, again, in some species they are plentiful, and
in others scarce; and in some individuals of all species it is difficult
to find them at all. On newly-caught specimens, however, they are
most easily found.

It is the genus Lycena, with its neighbour Danis, which affords
the scales now submitted to inspection in the plates. The upper-
side of the wings of the males is generally bright blue, but at all
events with more or less blue irrorations ; the males of certain species,
however, are brown. The females are generally brown; but even
when they have blue surfaces, I have found no plumules on them ;
while on the males which have any tinges or reflexions of blue, these
scales are present. No species, however, the males of which are
brown, yields these scales; and yet it is not in these peculiar scales
that the pigment or colour-refiexion resides. To a very eminent lepi-
dopterist I some time since wrote, asking if he was aware of any
other physiological difference between the blue and brown species.
His reply was, “that he could not think there was any other differ-
ence, but that it was a most interesting fact that when these males
imitate the females in colour, they lose another male characteristic.”

Mr. Sidebotham has, with habitual industry and kindness, drawn
figures of a large number of these scales; and some are represented
in the accompanying plates. These drawings are as truthful as
beautiful; the slides were mounted from insects in my own cabinet,
and I believe reliance may be placed on the correctness of the
nomenclature and habitat.

_ Nos. la, 40, 42a, 46, and 50, belong to the genus Lycena.
47, 48, 49, 52, and 53, belong to the genus Danis, according to
the arrangement of Doubleday, Westwood, and Hewitson, in their
‘Genera of Diurnal Lepidoptera,’ the text-book of general diurnal
lepidopterists. The under-sides of the insects of this genus are
unlike those of Lycena, but have a family resemblance of their own.
In constituting this a genus, our authors say of it, “ With general
characters of Lyczna, it appears very (perhaps too) close to Lycena.”
‘This is said without reference having been made to other than the
usual tests. The scales have certainly a peculiarity of their own.

The remarkable figures 38 to 41 cannot fail to attract atten-
tion; and at first sight it would be thought that they can have no

78 On the Battledore Scales of Butterflies, [Monthly, Mictoscopicat

relation to the others, and that the insects could have no natural
affinity ; but similar differences (inconsistencies, if you will) exist
in the Pieride, and it does not appear that insects nearly allied in
other respects are always furnished with similar plumules. It is,
however, possible that similarity in this respect may hereafter in-
fluence entomologists in their arrangements.

The scales represented by Figs. 1 to 387 and 42 to 53 are from
insects inhabiting various localities all over the world, each with
certain geographical limits. Most Butterflies have a rather narrow
range of habitat, as is the case with other animals; and some are
confined to very strait localities. For example, Morpho Ganymede
is known only as inhabiting a certain district of Bogota, the family
Acreea is found almost only in Africa, Ageronia only in Brazil; but
Pyrameis cardut ranges over the whole world, and Vanessa Antiopa
is excluded only from Africa. Now Lycxna betica, Figs. 38, 39, and
40, is also a cosmopolite, inhabiting all the localities of those repre-
sented in the Plates. In the ‘Diurnal Genera,’ before referred to,
its habitat is given as “Southern Europe, Java, South Africa, Mau-
ritius, Madagascar, Africa, India.” It has also been found in Great
Britain ; and I may add to the list Australia, the sect from which
Fig. No. 40 was taken having been captured by Mr. Diggles at
Moreton Bay. Figs. 38 and 39 are also from Moreton Bay, and
mere varieties of the same insect.

Collectors are now receiving from Australia insects previously
known as appertaining only to the Indian Archipelago; and it is
remarkable that while this island has an insect fauna of its own,
it should also possess the insects of neighbouring though distant
lands, and yet that its peculiar fauna, animal and vegetable, should
be distinct.

The insect whose scale is shown by No. 41 has been lately
named by Felder Dipsas lyczenoides ; it is questionable whether it
should be placed in the genus Dipsas. It is also from Moreton
Bay, and evidently allied to betica. The beaded or articulated
appearance at the upper end is very singular. The insect has an
evident affinity with betica, but in no other instance have I found
any scale approaching these.

The points desired to be insisted upon as useful in this investi-
gation are—

1. That these plumules are always identical in different indi-
viduals of the same species; and therefore mere geographical or
other varieties may be detected by this test; and that

2. In species nearly allied, so closely as to make them difficult
of distinction, these scales will be often found very different, forming
very certain and unquestionable divisions; while, on the other
hand, species of easy separation in other physiological peculiarities
have sometimes almost identical plumules.

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ANT. > The Monthly Microscopical Journal, August 11869

Scales of Lepidoptera.

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Monthly Microscopical
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On the Microscope Prism. 79
Microscopists have seen in some of the Foraminifera exquisite
forms of flasks and decanters; and in these plumules no one can
fail to observe their elegance, beauty, and applicability to industrial-
art purposes for forms and engravings of wine-glasses and goblets.
The following is a list of the names and habitats of the insects

to which the plates have reference :—

EXPLANATION OF PLATES XXL, XXII, AND XXIIL*

Lyc@Na.
Fig. 1. Alexis. Europe. Fig. 28. Methymna. Cape Town.
», 2. Icarius. < » 29. Atlianus. India.
» 3 Dorylas. ,, », 30. Hlpis. ‘
> te Damion. . ,, » ol. Celeno. _
yo a eACdORIS. —,, , 02. Erebus. Europe.
oj. On, ACIS. % », 33. Kandarpa. India.
» 7. Aigon. re » o4. Argiolus. . Europe.
5 8. Coelestina. ,, 5, oo. Unknown.
i: 9s Corydon. - ,, , 36. Pseudargiolus. Canada West.
» 10. Orbitulus. _,, , o¢. Unknown. Australia.
», 11. Theophrastus. India. 4) OS. Do. 3
5, 12. Alsus. Europe. 36 Ue Do. “
5, 13. Euphemus. ,, 0: Do. *
5, 14. Melanops. », 41. Dipsas lyceenoides. Australia.
,, 15. Unknown, and not named. », 42. Lyceena cardia. India.
,, 16. Sebrus, Europe. jo. 40 Lacturnus. __,,
» 17. Argus. 5 L aee Ayratus. Fe
» 18. Unknown, and not named. » 40 Cneius. Bi
a tO: 0. 5, 46. Unknown.
», 20. Optilete. Europe. » 47. Danis Hylas.
», 21. Hylas. os ie Be) new species.
», 22. Cassius, Brazil. Nii oP -
», 23. Unknown. India. » 00. Lyceena Alexis.
» 24. Telicanus. Africa. ero. ? new species.
», 20. Unknown. » 02. Danis, new species.
55 26. Do. » vo Sebee.
sepals Do.

IV.—On the Microscope Prism and the Structure of the Podura
Scale ; being a Postscript to the Paper “On the Diatom Prism
and Diatom Markings,” read before the Royal Microscopical
Society, June 9, 1869. By the Rev. J. B. Reade, M.A., F.RS.,
President of the Royal Microscopical Society.

THE paper on the Diatom Prism contained an account of the nature
and effect of the illumination as illustrated by the development of
Diatom Markings. These were new to me, and at none of our
meetings, either public or private, had I ever seen any exposition of

* We here beg to acknowledge most gratefully the extreme courtesy of the
Council of the Literary and Philosophical Society of Manchester, by which we are

permitted to reproduce the beautiful plates from its Transactions, in illustration
of Mr. Watson’s paper.—Ep. M. M. J.

80 On the Microscope Prism _ [Mortniy, Microscopical
the surface of the valves which led to any definite and exact know-
ledge of the structure. In the short discussion on the paper, in
which, by perhaps unavoidable circumstances, I was prevented from
taking a part, it appeared that some microscopists had for years
“considered the markings to be spherical.” Here, no doubt, an
erroneous method of illumination, though incapable of suppressing
the whole of the truth, was yet insufficient to reveal “nothing but
the truth,” and hence Mr. Slack very naturally distrusts the usual
mode of displaying diatom valves.
By breaking up a valve of P. quadratum, Mr. Wenham had
obtained single spherules, and had also detached a line of spherules
like a row of beads; but this most conclusive evidence still fails to
convince some observers that the law of Diatom structure is esta-
a ee blished. It is more than probable, how-
ever, that their doubts will be set at
rest by the single pencil of parallel
light reflected from the equilateral
prism.
Since the paper was read, I have
used the upper crown-glass hemisphere
of the kettledrum as a Brewster's
hemispherical prism, in which, says
- Brewster, the two convex surfaces are

ground at the same time;.and Mr. Ross
i made a deep double concave flint lens,
which is so placed within the converg-
ing cone (Fig.. 1) as to render the
emergent rays both parallel and achromatic. In ‘practice, how-
ever, I find it easier to obtain parallel light by placing the lower
hemisphere of the kettledrum, or any bull’s-eye lens, between the
lamp and the hemispherical prism (Fig. 2), and allowing the rays,

Fic. 2.

ae eee ee

t 1 1 %
1 ‘ 1
( i} 4

after crossing at the focus, to fall upon the plane surface of the
prism. These diverging rays are just sufficiently shut up by the
converging power of this prism as to be rendered parallel when

Muna, Aug Lies, | and the Structure of the Podura Scale. 81

reflected on the object under examination. Virtually, the point
or source of light is in the principal focus of the prism, and the
reflected rays are of course parallel. We thus obtain great intensity
of illumination, which may be useful in the examination of certain
structures, and the little vivid disc of light is easily thrown into the
centre or on any part of the circumference of the field ; but hitherto
the plane prism has answered every requirement in the examinations
I have made, and of these one of recent interest has been the scale
of the Podura.

In the interpretation of this standard test object—the Podura
scale—the value of parallel light from one source of light only will,
I think, be admitted by all observers. But those who are about to
use it must expect to see what they have never seen before; for I
ean truly say with Mr. Wenham, whose results on a dark ground
are a very close approximation to my own results on a light ground,
that “this appearance is so different from anything before seen in
the Podura, that were I to exhibit it as such, not one of its nume-
rous friends would recognize it.” It is no slight satisfaction to
feel that the support of so high an authority as Mr. Wenham will
tend to make a priori objectors cautious. Mr. Wenham’s paper is
published in the ‘ Monthly Microscopical Journal’ for July. 3

The following description is accepted by friends who have
worked with me. The scale of the Podura consists of two mem-
branes, between which there is a series of small solid spherules.
These spherules or beads are often arranged in parallel rows
towards the edge of the scale, and in the centre they are placed
rather diamond-wise. Under a power of 12,000 linear, I have found
24 spherules in ;),,th of an inch on the 12-inch horizontal dia-
meter of the field and 6 on the vertical diameter. Hence, in the
latter direction they are about sooth of an inch apart, and in the
former, the interval being equal to a diameter of a spherule, they
are about zgdyoth of an inch apart. If now we could place a
series of spherules in almost close contact on the vertical diameter,
we should have parallel rows of about 48 spherules enclosed between
the membranes as in a tube, and the membranes themselves would
touch and be in close contact along the parallel intervals. Now let
this close contact of the membranes continue, since in point of fact
it really does exist on the scale, but remove the spherules we have
supposed to be inserted. Then we have an empty space like the
empty finger of a glove between spherule and spherule on the
vertical diameter of the field. The sides of this tubular space can-
not preserve their parallelism without the support of the supposed
additional spherules, and therefore they tend to fall together, having
the diameter of the existing spherule for the width of the tube close
to the spherule, and thence tapering to a point just before a lower
spherule is reached. Thus we have on the vertical 12-inch dia-

VOL. II, G

ae : Monthly Microscopical
82 On the Microscope Prism TE

meter, under a power of 12,000 linear, a set of 6 spherules at the
top of 6 hollow cones of membrane, which may be shown as brilliant
objects on a dark ground, while at the same time they naturally
prevent the direct light of the usual achromatic condenser from
passing through them. If this is the true interpretation, and I
believe it to be so, it is a curious fact that simple darkness in the
hollow cones—the absence of light and not the presence of shadow
—supplies our skilled opticians with their best test in the shape of
‘a note of exclamation,” having exquisite definition and apparent
materiality. But if, instead of using direct light, we so place an
equilateral prism as to throw a parallel beam of oblique light along
the length of the scale, the shadow of the raised membrane which
forms the hollow cone disappears, and we immediately get rid also
of the interior darkness, and therefore of all trace of “ exclamation ”
except that which almost naturally arises at the now novel sight of
nothing but small spheres upon what we know to be a scale of the
Podura! The object seems to be—as by Mr. Wenham’s method it
really is—ailluminated from above, and the “bright blue circular
spots” of Mr. Wenham are seen by transmitted light and natural
shadows to stand out in full relief as distinct spherical bodies.
These spherules may often be distinctly seen on the margin of the
scale, and in more than one instance I have seen them as detached
bedies near the scale.

Among the “variety of modes of illumination” alluded to by
Mr. Beck, there are no doubt some which are calculated to mislead
us; but the equilateral prism is a safe guide, and much information
respecting the structure of the Podura scale may be readily gathered
by throwing the parallel beam of light in various directions on
its surface. Most of the peculiar characteristics pomted out by
Mr. Wenham become apparent, as well as the new features above
described; and, notwithstanding the difference in our modes of
examination, we come to the same conclusion that the markings are
“not real spines,” but “so incorporated with the membranes that
separation cannot be effected.”

The equilateral prism which I used in the first stance for
supplying a single pencil of parallel light is 5 inches long with
one-inch faces. It was made about thirty years ago of the well-
known white sand which abounds in my old parish of Stone. I now
use with equal effect and easier management much smaller prisms
of an inch and even half-an-inch in length, with inch and half-inch
faces. Mr. Ross has adapted these prisms to my microscope,
mounted on a small arm with ball-and-socket joint. In a popular
instrument the expensive luxuries of a mechanical sub-stage and
elaborate condensers may be dispensed with, and the Prism Micro-
scope, consisting of the body with its powers, a thin stage, and a
two-inch equilateral prism, will look like a good working tool, and

Mona, Aue wwe | and the Structure of the Podura Scale. 83

cannot fail to interpret the minute wonders of Creation to many
intelligent admirers of Nature.

P.S.—July 21.—In consequence of a question just put to me
by one of the early Fellows of our Society, the Rev. Charles
Pritchard, between whom and myself the microscope was in years
long gone by a bond of union, I find it necessary to add a few ad-
ditional remarks. The question is, “ How does the prism, as such,
effect the work better than a good plane surface?” Before answering
the question I thought it better to examine the quantity and nature
of the light which is reflected up the tube of the microscope from the
left-hand plane face of the prism—an angle of the prism being
towards the object on the stage—and the same light which passes
through the same face of the prism and is totally reflected up the
tube from the adjacent face or base of the prism, by turning the
prism a little on its axis, the prism lying nearly under the vertical
diameter of the stage. My report may “sound like a fable,” but
nevertheless the difference is marvellous. ‘The whole light of the
lamp totally reflected is not perceptibly altered either in nature or
quantity, but the portion reflected from the face, and not entering
the prism, is a purely polarized beam! As such I have used it in
the examination of several suitable objects, passing it through sele-
nite plates where necessary, and I prefer the results to any pre-
viously obtained by the direct light of a common Nicol’s prism.
Salicine and crystals generally, as well as fine vessels in animal
and vegetable tissues, are seen in almost stereoscopic relief, in con-
sequence of the shadows which are readily thrown by a slight
obliquity of the polarizing pencil. ‘This obliquity may be extended
to the bringing out the effect of polarized light even on a dark
ground, and thus, as in the combination devised by Mr. Furze,
heightening the solidity by the play of colours.

The plane prism may be used in other instruments as a polarizer,
but it 1s satisfactory to find that the prism microscope is independent
of extra appliances for producing polarized light.

IT will only add, that when the sun itself is reflected from a sur-
face of the prism, its disc being seen at the bottom of the tube, the
phenomena of polarization, so easily exhibited, are brilliant in the
extreme. The eye, also, is not fatigued by the brightness of this
one component part of the sun’s light; but the whole light totally
reflected from an inner face of the prism would be intolerable. The
brightness of the polarized beam may, however, be diminished to
any extent by simply placing small pieces of white linen of different
thicknesses between the prism and the sun.

The plane speculum of a Newtonian Telescope exhibits less
polarization, both with daylight and lamplight, than the plane

G 2

84 On Methods of [*sournat, Aug. 1 1869.
surface of an equilateral prism, but far too much to allow it to take
the place of the prism which alone supplies a beam of pure un-
polarized light at the angle of total reflexion.

V.—On Methods of Microscopical Research.
By Herr §. Srricxer.*

THE microscope is an implement of research. When objects are too
small to give, at the necessary distance from the eye, a sufficiently
large image on the retina, they require a simple or compound
microscope for their investigation. But the field over which the
investigation ranges is not determined by the employment of such
an instrument. Microscopy denotes not a doctrince but a method
of investigation, the most delicate indeed of its kind for terrestrial
objects, for our microscopes now are the most perfect of optical
instruments.

The most extensive use has hitherto been made of the micro-
scope in the investigation of organisms. The knowledge of the
more minute structure of the tissues of the vegetable and animal
body, and especially of the latter, has been raised to an independent
science, which branches again into important subdivisions. Normal
tissues, and those altered or produced by abnormal influences, form
already the basis of two distinct—though very intimately connected
—sciences, and either may again be considered from two points of
view. We occupy ourselves with the morphology or the biology
of tissues, or, as 1t may be also expressed, the normal or patholo-
gical anatomy, or the normal or pathological physiology of tissues.
Morphology and physiology of tissues are, however, so intimately
related to each other, that we cannot now think of a separation of
the two. The observation of the vital phenomena of tissues, and
experiments with them, will lead us to a large knowledge of their
most intimate structure, whilst, vice versa, a research into their
structure will facilitate our conclusions in regard to certain vital
phenomena.

The methods which have been applied in these two departments
are different. To watch the vital processes under the microscope,
and then to influence them, require other means than those which are
necessary for acquiring a knowledge of only the forms of the elements
of the tissues. Besides, experiments under the microscope upon
living objects are of a different nature from those upon dead ones.
The sensitiveness of the former to external influences renders, in even

* Translated from the ‘Handbuch der Lehre von den Geweben.’ Leipzig:
Engelmann, 1868.

Ee noe Microscopical Research. 85

the microscopically small space of the instrument and under the
necessary conditions of its employment, experiments possible which
would be out of the question with portions of dead tissue. Slight
changes of temperature, feeble electric currents, and weak acids are
sufficient to induce changes in living tissues. But if experiment is
to be made upon dead tissues, then more powerful influences are
required than the delicate instrument or the observer stooping over
it are always able to endure. The greater sensitiveness of living
organisms renders very delicate manipulation necessary, but at the
same time it facilitates experiment. To this also must it be ascribed
that only of late years has the latter fact been more largely recog-
nized, namely, about the time when the investigation of living tissues
became more extended.

The tissues may be examined either by the light which they
reflect from their surface, or by that which they give passage to—
indirect or transmitted light. tn direct light every object may be
examined, provided it receives and reflects light enough, and that
both object and microscope can be fixed.

It is self-evident that the instrument must admit of being
focussed, otherwise it will not be possible to obtain well-defined
retinal images in all the cases coming under examination. Great
enlargement must be dispensed with in direct light, because the
distance between the objects and the lens must here be small ; so
that strongly magnifying lenses cover the object and interfere with
its illumination. It is, however, possible to apply illumination on
the principle of the ophthalmoscope, and then the difficulty indi-
cated is overcome.

The investigation in reflected light gains very much by direct
illumination, or, what is still better, if a focal image of the source of
light is thrown upon the place of the object to be examined, details
will then often appear which can scarcely be observed in diffused
daylight.

If longer distances are required in the examination by direct
light—as, for example, when we work under the microscope with
larger instruments, or when objects have to be viewed or pre-
pared under liquids—Bricke’s magnifier will be found serviceable.
This is put into the arm of Nachet’s or Hartnack’s stand, and the
object placed upon the stage. Focussing is then effected with the
unaided hand by moving the magnifier. This combination is of
great service in the case of delicate preparations with needles, such
as the isolation of ganglion-cells, or the exhibition of minute fibres.
There the objects are in every case placed upon an opaque ground
—on an opaque grey ground if the object is dark; on an opaque
black ground if the object is clear. The object to be dissected out
can, in every case, be placed upon a glass plate, and under this a
dead white or black slip of paper, as the case requires. For the

bi On Methods of monty een

examination of a larger fragment of tissue in fluids, small capsules
should be used, which rest upon a flat base, and have a spheroidal
cavity, somewhat like the saltcellars in common use. An opaque
dull ground may easily be obtained by coating the surface with a
thick layer of coloured wax or gutta percha. At the same time
a basis is thereby gained to which the objects may be fixed with
needles.

If it is a matter of importance to get a view of the objects in
strong relief to see the details on their surfaces, then the magni-
fiers of Steinheil of Munich are especially to be recommended ;
but it is advisable that they should be supported by a ball-and-
socket arm, which can be moved both horizontally and vertically
on a fixed stand; if forceps and scissors are to be used in making
a preparation under a high magnifying power, then the capsule
for the preparation should be placed upon a blackened block of
wood, several centimetres high and resting directly upon the table.
In such cases preparations are made more safely if the arms can
rest upon the table in a position nearly horizontal. In working
under powerful magnifiers, the nose of necessity comes nearly in
contact with the preparation, and the bridge of the nose may then
be made use of as a support for the cuttmg instruments em-
ployed. The preparation with scissors and forceps under strong
powers requires, as a rule, a very great steadiness and a very exact
guiding of the cutting instrument, and it is almost indispensable to
support it somewhere when a careful dissection has to be made of
small and delicate objects. When the left eye is applied to the
lens the right hand can direct with great safety a pair of scissors
balanced upon the bridge of the nose, whilst the other hand fixes
the object. In fixing any delicate objects, heavy forceps should be
made use of with fine but not roughened points.

In working by direct light with compound microscopes only,
the lower objectives, as far as No. 5 of Hartnack’s microscope and
the corresponding ones of other instruments, can be used. For
making preparations compound microscopes of low power were
formerly employed, in which the image was erect or had the same
direction as the object.

These so-called dissection-microscopes can be easily dispensed
with, siace one very soon gets accustomed to the inverted images
as regards the inverted guiding of the hands.

Investigation with transmitted light can likewise be undertaken
with both simple and compound microscopes. As regards the use
of the former, we can add but little to what has been said before.

When an investigation is to be made in transmitted light, the
support must of course be transparent, and the object must be illu-
minated by a reflexion apparatus, placed below it, in the form of
either a prism or a mirror. Simple microscopes, or the low powers

Bree crosoptcal Microscopical Research. 87

of compound ones, are only employed in transmitted light when
it is required to ascertain the general forms and relations of the
tissues. The larger the object is the lower must be the mag-
nifying power, if it is desired to give a complete view of it. In
the case of larger objects, however, a general view is taken with
a low magnifying power, and then the details are studied by going
over them with a higher power. The very powerful lenses recently
manufactured by Hartnack serve chiefly for the examination of
living tissues, or of isolated, well-preserved tissue elements. In
tissues which have been, for the purposes of investigation, sub-
mitted to rough treatment—which have been, that is to say,
hardened by reagents, coloured and repeatedly washed—a high
magnifying power brings out at first sight little more than those
of average power; indeed the eye less skilled can see in such
cases less clearly, when using Hartnack’s No. 15 than when using
Hartnack’s No. 8. But high magnifying powers are even here an
invaluable aid for the beginner when the definition of deep struc-
tures is required. It is necessary to use the screw with the
ereatest caution and to turn it only very slightly, so as to obtain
after each slight turn of the screw a new field of vision on which to
rest, and observe whether to proceed next to a deeper or higher
one, to advance or withdraw.

When we have to do with isolated and particularly well-pre-
served elementary forms; and further, when the preparations are
examined when recent and without the addition of fluids, or of
such only as do not affect them, the greatest advantage is derived
from the use of high magnifying powers. The advance in our
knowledge of the cell and of the finer structure of the nerve-fibre
rests upon investigations with the excellent instruments of modern
construction. ‘The examinations of the cornea in the living state,
as they were commenced by Recklinghausen and Kthne, must
convince us more completely of the value of high magnifying
powers. It is indeed true that the structure of the cornea, when
fresh, cannot be made out even with the best magnifying powers.
Tn its recent condition, only such tissue elements can be distinctly
seen as refract light otherwise than do the parts surrounding them.
Thus, if fibres or cells are imbedded in connective substances or
an interstitial fluid, the optical behaviour of which does not differ
from that of the tissue elements, then they cannot be seen even
with the best magnifying powers; artificial means must be re-
sorted to.

These are either mechanical for the purpose of tearing from
each other the tissue elements, or they are chemical, the use of
which consists in such cases in either dissolving the cementing
substances, or changing them differently from the elements them-
selves. ‘The best artificial preparations, however, cannot replace

88 On Methods of [ sroneee ee ee

that which observation in the fresh state yields with a power
magnifying 1000 to 1500 times. Those contours which can be
recognized even during the life of the tissues show beside their
sharpness a peculiar softness, which makes observation agreeable.
The natural cavities and fissures are exceedingly well marked from
- their surrounding parts in consequence of the different refracting
power of their contents. Lastly, contours are visible during lie,
which disappear with the death of the tissues. Though by special
reagents these can again be made visible, they acquire their full
value only by our knowing that they have been visible even with-
out reagents.

According to what has been said of the present state of instru-
ments, it may be expedient to conduct comprehensive topographical
studies with weaker lenses, the study of tissues in preparations
modified by treatment with medium lenses, and to employ strong
magnifying power in such cases only for controlling the depth-
distances (?), and lastly to carry on the investigation of fresh tissue
exclusively with the best existing instruments.*

The simplest, but at the same time the most successful and
most elegant, way of examining under a compound microscope is by
laying the object upon the middle of the highly polished glass
slide, covering it with a thin quadrangular plate of glass, likewise
perfectly clean. The glass plate, also called the glass cover, ought
to lie with its surfaces parallel to the glass slide, which can only
be effected when the stratum to be examined spreads out regularly
to a greater extent than it. Irregularly bordered thick lumps
interfere with the examination by forcing the glass cover into an
oblique position. If the tissue to be examined is distributed through
a fluid, a small drop of it should be placed upon the glass slide ; the
top of the drop is then to be gently touched with the glass cover,
and this then allowed to descend slowly upon it. The inclusion of
air-bubbles is thus avoided. If the investigation is to be carried on
for a longer time, or if we are anxious that the medium in which
the tissues lie shall not become more concentrated at the margins,
then it is better to apply with a brush a layer of oil round the
margins of the glass cover; the preparation will, in this way, be
protected from evaporation. If after the application of the glass
cover, a part of the fluid to be investigated should flow beyond its
margins (the glass cover acquiring thereby an unsteady and easily
movable position), then its margins must first be dried with filter-
paper, after which the layer of oil may be put on. In this way we
obtain the simplest moist chamber.

* To the binocular stereoscopic microscopes, I cannot attach much value for
the service they have rendered hitherto. Up to the present they have been used
with low magnifying powers only. But with the simple microscope the appearance

of relief may be obtained exceedingly well if, during the observation, the head is
maintained in a slightly oscillating motion.

ee Boe Microscopical Research. 89

Recklinghausen has introduced the use of moist chambers.
The fundamental idea for such an arrangement was that the object
be introduced into a space, saturated with aqueous vapour, and this
appeared especially necessary when it became desirable to examine
without the glass cover. In such a case the object is partially
surrounded by an atmosphere, to which it gives off aqueous vapour
should the atmosphere not be saturated with such vapour already.

If we, on the other hand, take into consideration that the
deposition of aqueous vapours from a saturated atmosphere upon
such an object is dependent on the temperature of the latter, it will
be easily understood how difficult it is to arrange everything in
such a way that water is neither taken up nor given off. At any
rate the errors will diminish with the dimensions of the atmosphere
which surrounds the object. The atmosphere should therefore be
made as small as possible, and should as much as possible be
reduced to nil, therefore as long as possible one should work with
a glass cover the margins of which are oiled. The pressure which
it exerts upon the object is inconsiderable, while it can easily be
avoided. It is only necessary to make a wall of oil, to apply the
drop within this wall, and then to cover it, in order to be protected
against the pressure exerted by the glass cover. But as regards
the experiment, it may from other causes become necessary to
surround the preparation with an atmosphere. The influence of
various gases, for example, may have to be passed over it in the
course of the experiment. In such a case an actual chamber must
be established, and this must be kept as small as possible as long
as no other arrangements are made to regulate the movements of
the aqueous vapour. For this purpose I would propose to apply
upon the ordinary slide a ring of putty of the required thickness, to
place the object, as is now practised everywhere, upon the glass
cover, to bring this down upon the wall of the putty with the
object turned downwards, and to press it down gently by running
the handle of the scalpel over it. A drop of water upon the bottom
of the slide will suffice to saturate the space with aqueous vapour,
and to preserve the object from drying. But here also great
caution should be used, for it will be found that the dry and
polished cover-plate is tarnished as soon as it is put upon the wall
of putty. The drop of fluid must therefore have a small surface,
in order not to evaporate too much; it must, on the other hand,
not be too small, lest the object dry too soon.

Such a chamber may easily be transformed into a so-called gas
chamber. Into either side of the soft wall of putty, corresponding
to the middle line of the glass slide, a small glass tube may be
introduced, to each of which is attached a correspondingly diminu-
tive caoutchouc tube. When no gas is to be sent through them,
they are closed by small pinch-cocks. When the gas is to be passed

90 On Methods of [ental Mteroscoptea
through, the necessary communication is to be established with the
caoutchouc tubes, and the pinch-cocks opened. Those, however,
who work more frequently with gases will not be satisfied with a
provisional chamber so easily destroyed. Then it is better perma-
nently and firmly to cement the conducting glass tubes into grooves
in the glass slide. The space, which is to be filled with gas, can
then be again enclosed by a wall of putty.

A slide, which is used for such examinations with gas, must be
held down upon the stage of the microscope, because the conducting
gas tube drags on it, in consequence of which the object may be
moved out of its position during the examination. The gases
should be evolved from wash-bottles which are fixed upon the table,
so that definite relations may subsist between the wash-bottles and
the microscope, whatever may be done with the gas apparatus
placed at a distance from the table. ‘That I may be quite indepen-
dent in my microscopic labours of the aid of assistance, and in order
that table and hands may not be taken up with other than purely
microscopic objects, I arrange my gas apparatus below the table in
such a way that by movements of the feet I am enabled to set the
one or the other agoing. If carbonic acid, for example, is to be
made use of, I place the apparatus below my table in such a way
that a bottle holding the hydrochloric acid can be raised from the
floor by means of a foot-board and a cord running over pullies, and
the acid thus caused to run into the evolution-bottle by a caout-
chouc tube passing between necks in the lower parts of the bottles.
From the evolution-bottle a caoutchouc tube leads then into the fixed
wash-bottle on the table, and from this proceeds the communication
with the microscope. ‘The conduction of carbonic acid to a micro-
scope requires, however, the possibility of its exchange for atmo-
spheric air. I insert, therefore, a T-shaped tube between the
wash-bottle and the glass slide. The direct arm of this tube lies
in the line of communication between the wash-bottle and the glass
slide, with the cross-piece turned towards the observer. ‘To this is
now attached a long caoutchouc tube, the extremity of which the
observer holds between his teeth. Between the T-shaped tube and
the wash-bottle a clamp is applied. If I now open the clamp, lift
the bottle containing the acid by treading down upon the foot-board,
send in this way carbonic acid into the wash-bottle, compress at
the same time the caoutchouc tube between the teeth, the gas must
pass over the slide. But if I close the clamp, and suck at the end
of the tube in my mouth, I draw atmospheric air into the chamber
from its opposite side. Thus it is in one’s power to introduce a
succession of atmospheric air and carbonic acid whilst observation
is being carried on, and the hands are left free for necessary mani-
pulations. A second, so-called Deville’s apparatus, under my table
arranged in the same manner as the first, is suitable for the evolu-

See | Microscopical Research. 91

tion of hydrogen. This gas I use as an indifferent reagent, in order
that it may carry with it in its passage through a wash-bottle
vapours derived from its contents—for example, ammonia, chloro-
form, &c. The same object is obtained by a pair of bellows
worked by foot and furnished with a delivery tube leading into the
wash-bottles. When hydrogen is wanted as such, the gas chamber
described is not sufficient. Kiihne, to whom we owe the first expe-
riments with gas chambers, proposes for this purpose a mercury
joint. Following this principle, I take a slide formed of hard
caoutchouc, the middle of which is perforated, and to one surface of
which a glass plate is cemented, or, what is the same, I cement to a
glass plate a ring of hard caoutchouc. The surface of the ring
opposed to the plate is now to be provided with a groove surround-
ing the space, into which groove mercury is to be poured.

The glass cover must then by means of hard cement be converted
into a vessel resembling the lid of a box. ‘To the inner surface of
this vessel the object is then applied, and its side walls dropped into
the groove so as to dip into the mercury. Then, if the glass cover
is held down by clamps, the gas chamber is tightly closed, and, as
a matter of course, gases may be introduced by suitably applied
conducting tubes.

There are certain difficulties attending the examination of
objects in gas chambers. We will take the simplest case. A drop
of blood is applied to the under-surface of the glass cover; the
latter is placed upon the chamber, and firmly cemented to it. ‘The
first stream of gas which passes through is quite sufficient to dry
the blood at its edges. This evil can scarcely be remedied. It is
therefore necessary to accustom oneself, in the case of gas chambers,
to very quick experiments, or else to add to the preparation so much
indifferent fluid as that the preparation itself may, without being
injured, saturate the little chamber with water-vapour. We work
then no longer under the simplest conditions, and the conclusions
of which the experiment admits must be referred to the conditions
under which we set out.

Still more difficult is the employment of the moist chamber,
when the object under the microscope has to be heated.

It was Rallet who introduced the change of temperature into
microscopic experiments. Max Schultze has improved this experi-
ment, since he constructed a heating-stage which, adapted to the
ordinary stage of the microscope, heats it throughout, thereby giving
any desirable temperature to the object. It has been tried to elevate
the temperature of the object in different ways. In Max Schultze’s
stage, direct conduction by metal plates has been applied as the
principle of heating. Then an attempt was made to conduct warm
iluids through the stage, and lastly even warm vapours were used
in the same way. Before any of these devices, the plan of heating

92 On Methods of Microscopical Research. [Monthly Microscopical

the stage by converting constant currents into heat recommends
itself to us. In microscopic experiments only very small quantities
of heat are required, and it is not at all necessary for the stage to
be heated throughout its whole extent, but only its centre, or what
is still better, a glass plate inserted in a caoutchouc plate. Such
small quantities of heat might be expected from the circulation of
even weak currents. It is known that the heating of a wire which
forms part of the circuit of a constant battery increases as the
thickness of this wire diminishes—according to Riess, inversely as
the square of its diameter. It is therefore only necessary to fix
a correspondingly thin wire into the middle of a glass plate, put
the two ends of the wire in communication with the electrodes of
a constant battery, and close the current, and the glass plate gets
heated. The cementing on of a wire is, however, inconvenient ; we
have an excellent substitute in tinfoil. Thus I cut the tinfoil in the
form of a picture-frame, with two arms projecting from opposite
sides, gum 1t to a slide, and connect the two ends of the tinfoil with
the poles of the battery, and our object is attained.

A very convenient method of connecting it with the battery is
the following :—Brass springs are added to Hartnack’s microscopes,
by means of which the preparation can be held in a desired position.
These springs, which are inserted by brass pins into hobs in the
stage, I provide with caoutchouc pins; thereby they are isolated
from the microscope. Whilst retaining the object-bearer in its
place, they can at the same time press upon the broad ends of the
tinfoil. I need then only affix a conducting-wire on any part of
the spring on each side, and the circuit is closed by the tinfoil. A
second strip of tinfoil of the same width as that affixed to the slide
wound round the bulb of a thermometer, and inserted in any part
of the circuit and suitably protected, indicates the temperature
which the centre of it must have, if all secondary conditions are
the same in both cases. These secondary conditions, however, may
be met by the judicious use of the thermometer, which is necessary
in all cases, according to whatever method the heating is carried on.
A quantity of fat, the melting-point of which is known, should be
put upon the place where otherwise the object would be placed, to
ascertain the height of the column of mercury at the moment when
the fat begins to melt. The fat should moreover be employed in
pieces of microscopic size, and be watched through the microscope.
It is best to cut a disc out of the fat, to cover it lege artis, to view
it with a given base, and to make use of it for this lens.

Monthly, Microscopical) — Obyect-glasses for the Microscope. 93

VI.—On the Construction of Object-glasses for the Microscope.
By F. H. Wenuam.

(Continued from page 347, No. VI.)
On the Production of Spherical Surfaces in Glass.

As the radii required in the construction of microscopic object-
glasses are seldom very long, the templates for all sizes above
ith of an inch in diameter are usually made of steel, such as thin
saw, spring, or busk-steel, not softened, but turned hard, as obtained.
A hole is punched through the middle of a square plate with a
centre punch, the hole is then rounded out with a taper rimer.
The piece of steel is next broken round as near as possible to the
size of the circle required, by clamping it in the vice and driving
off the surplus metal round the edge with a chisel held close to the
jaws. ‘This steel plate is driven on to a mandril so as to turn true
without any wabble. The lathe is run at a slow speed, and the
T-rest placed rather high near the top of the work, which is turned
true with the common square graver held over-hand. The cham-
fered edge of the templates may form an angle of 90°. Every
convex template should have its counterpart or concave; the steel
plate to form this is clamped flat on to a face-chuck by a ring with
two opposite screws tapped into the plate. The inner circle is
turned out with a side tool, consisting of an old saw-file ground to
‘a point on the three faces. The turning is continued till the disc
or gauge just drops through; the inner edge is then chamfered
from both sides.

Gauges below ith of an inch in diameter are made from steel
wire turned to the annexed form (Fig. 1). The
disc end is hardened by heating it with the lamp
and blowpipe, and quenching it in oil, and the
counter-gauges are most easily formed by a coun-
ter-sink rose-bit run in the lathe. The plate of steel is chamfered
out alternately from opposite sides, by forcing it up on the socket of
the back centre, till the dise will pass through; the hollow tem-
plates are, of course, cut in half before they can be used.

An instrument for measuring the diameter of the discs, &., is
indispensable. It consists of a pair of sliding steel jaws, with a
vernier and nonius capable of being read off to thousandths of an
inch, and is sold by the watch tool-makers.

The moulds for grinding minute lenses are always of brass ; they
are also used in pairs. The concave is turned out to the gauge,
and the convex to the counter-gauge. For small radii the hard
gauges are finally used for the last correction, as a turning, or

Fig, 1.

94 On the Construction ee ee
rather scraping tool, and finished by grinding the two moulds
together with the finest emery.

There is some difference in practice between the grinding of
lenses for long and short radii. In the former, as for telescopes,
the glasses are fixed, or have but a very slow rotary movement,
and the concave tool is worked over them, either several at a time
in blocks, or else, if a shallow curve is required, only on one single
disc : this is placed in the centre, and a number of smaller pieces of
glass planted round the circumference to support the figure, the
whole being ground as one. But in the lenses to which this paper
particularly refers, the concave tool is invariably caused to revolve
rapidly, and the convex lens worked into it. For the longest
radii and lowest powers the ordinary foot-lathe is suitable, but this
is not so well adapted for grinding and polishing very minute
lenses. A bow lathe, such as used by watchmakers for heading
their screws and other purposes, is far preferable, This tool is
represented half size by the annexed cut (Fig. 2), and scarcely needs

Gas

explanation; it has a hollow screwed mandril and T-rest, and is
held in the vice by the tongue at the bottom, The pulley has
three speeds, the smallest of which is three-eighths of an inch in
diameter ; it should also have a socket for carrying a fixed magnifier,
under which the minutest lenses are turned. The best bow is an
old fencing-foil ground down so as to be very thin and light.
Catgut does not answer well for the string, as it soon gets frayed
out over the small pulley. I have found the best packing-twine
preferable. During work this is kept slightly moist, and rubbed
with a piece of soap; in this way a length of it will outlast a day’s
work, especially if a little more twisted before it is attached to the
wire hook at the top of the bow. A surplus stock of string may
be wound about the guard, just above the handle, so that it can be
drawn out as required.

The same rules for guarding the extreme edges of lenses should

Monthly, Microscopie] of Object-glasses for the Microscope. 95

be observed, as described in prism-work, shown by the following
examples. Fig. 3 represents a plano-convex lens which has been
made and finished upon a flat disc of
glass, to which it has been attached
with hard Canada balsam. The two
discs are cemented to the stick with
black sealing-wax; the lens and sup-
porting disc are rough ground on the
zine plate till they nearly fit the concave gauge, they are then
ground in the brass mould till the lens measures very nearly the
diameter required, leaving a small allowance for smoothing and
polishing.

For double convex lenses, the disc of glass, cemented on a stick
as usual, is first ground and polished on one side. A piece of
glass tube of suitable size is selected for a handle, and the end of
the bore ground out to a similar radius; the polished side of the
unfinished lens is then cemented
into this concavity, and the lens

and tube ground and polished off
together, as shown by Fig. 4, taking
the same precautions as before to a

work the lens up to the exact
diameter required. The dotted lines show the rough disc as
cemented down. By this method all the marginal errors are taken
up by the glass tube-holder, of which an assortment of various sizes
will be required, from a minute bugle, up to half-an-inch or more
in diameter. Before using the holders again for other lenses, the
end must be ground out on each occasion, so as to increase the
diameter of the cup. The lens, when taken out by being warmed,
will have a knife-edge perfect to the extreme.

In minute lenses, some difficulty will be experienced in obtaining
the measurements by means of gauge instruments, when near the
right diameter. I therefore, for small sizes, always use the micro-
scope with micrometer eye-piece, having previously taken the exact
size from the diameter of the cell in which the lens is to go. This
is very accurate and convenient. After the finished lens is taken
out of the holder, if it should be found too large to enter the cell, it
may be slightly cemented to the end of a wire, and twisted into a
piece of the finest emery-paper, held in a hollow form, and the keen
edge is taken off till it passes through.

The single fronts for the highest powers, from their form, do
not admit of being ground in this way. A piece of brass or steel
is screwed into the mandril, and the end turned of a size to enter
the cell into which the lens is to go; the end is turned flat, or
rather slightly hollow, and the centre taken out. A piece of crown-
glass is cemented by its polished side to the flat end, with the best

Fic... 3.

Fic, 4,

LS
~—

eee Se ee

96 On the Construction (se ee
orange shell-lac, and turned with the diamond point till it nearly
enters the cell. The last finish may be given by fine emery-paper
wrapped round a flat piece of hard wood. ‘The extreme end of
the glass is then turned off flat, till it equals the thickness of the
intended lens, from the apex to the flat, as measured by the jaws of
the gauge; the lens is next turned off by the diamond to the curve
required, as shown in the cut (Fig. 5); and,
finally, the chuck is removed, and the lens
eround and polished in the mould as usual.
In all cases of cementing lenses on to chucks
in this way, care must be taken that they are
well pressed down, so that the layer of cement
may be of the same thinness all round, otherwise the lens will be
tilted and out of centering from unequal thickness. When taken
off, the lac may be cleaned off with alcohol.

A similar mode of chucking is employed for a plano-concave
lens. The polished flat side of the flint glass is cemented to the
chuck, made just to enter the cell; but in order to appreciate the
thickness in the centre, the circumference of the disc, after it is
turned to fit the cell, is polished with a piece of hard wood and
crocus. The concavity is then turned out a trifle deeper than the
radius of the circular gauge, till a mere line of light only is observ-
able by looking through the polished edges. The chuck is then
removed from the mandril, and the lens thereon ground and finished
on the convex tools.

For a double concave lens, such as is used for a triple back, the
end of the chuck, instead of being flat, must be convex, to match
the radius of the concave surface of the disc of glass that it is to
receive, this having been previously ground out and _ polished
independently in the usual way of cementing it on to a stick; but
as the curves are shallow, it is best not to turn the disc down to
the intended size at once, but leave it much
larger than the cell or chuck, thus (Fig. 6);
Mi / and after it is polished as before directed, the
| \ chuck is again screwed into the mandril, and

_ the lens turned down so as to fit the cell; this
is done in order to avoid the marginal errors
which would arise from working a shallow curve of small diameter.

The same precautions have to be observed in smoothing lenses
as directed for prism-work; the finest emery is used, and the
requisite moisture applied as required by breathing on the lens,
taking care that the accumulation of powder is removed from time
to time from where the centre of the mould has been dug out,
otherwise this may contain some coarser particles that may cause
scratches.

As before remarked, the moulds are made in pairs; the convex

Fig. 5.

Fig. 6.

ANAT
\ \\\\
\\\\

\ \\

\ \\ \\\\

Monnet, Mua wes | of Object-glasses for the Microscope. 97

and concave are turned to their respective gauges, and then ground
together. The diameter of the mould should always rather exceed
that of the lens intended to be ground; and the centre, or “ pip,”
is taken out; unless this is done, a prominence is left at this spot,
which injures the work. During the smoothing, the two moulds
should occasionally be worked together, as this greatly tends to
ensure the accuracy of figure of the lens; and after this is com-
pletely smoothed, the moulds should be again matched, so as to
leave them with a polished surface, for a reason to be hereafter
explained.

Having got our lens perfectly smoothed and figured, the next
operation is the polishing. It is almost impracticable to perform
this in the hard mould, and therefore various substances are em-
ployed, of a less degree of hardness, in which the coarser particles
of polishing-powder may become imbedded. For the larger sized
lenses in microscope work, beeswax, hardened with some resin
and finely-washed ochre, is very suitable; but for medium sizes
this is too soft and yielding; a mixture of shell-lac and washed
putty-powder is therefore employed, which is very enduring. These
are melted together and stirred diligently; the shell-lac is added
till the whole arrives at the consistence of thick paste; and as the
lac is apt to burn, to prevent this, a lump of beeswax should be
thrown into the mass. This does not actually mix with the other
ingredients, but lessens the risk of spoiling the composition by
overheating: when cool enough this may be rolled into sticks
between two greased boards.

For the very smallest lenses, such as the fronts of a ;th and
soth, the last composition is still too soft and fragile to maintain a
true figure. The polishing mould is therefore, for these, made.
in the end of a rod of pure tin, which is cut out into a nearly
hemispherical cup by the appropriate steel gauge; the “pip” is
removed with a needle-point.

The wax-polishing bed is turned out to the required radius,
and finished by scraping with the steel gauge; but as the material
is somewhat yielding, the lens soon plys to the mould and keeps its
figure during the polishing.

The second composition is very hard and brittle, and does not
yield at all, and as the body is composed of the hard oxide of tin,
this would speedily injure the gauges if used as cutting tools. The
method that I have adopted for forming the polishing moulds from
this substance is as follows:—A lump of the material is fastened by
heat into a ferrule, or hollow cup, running in the lathe; the end is
then turned either convex or concave, and of a diameter suitable for
the lens to be polished; the convex or concave mould, as required
(which has been worked off at last near to a polish, as before ex-
plained), is then screwed on to a handle, and held in a flame till,

VOL. II. H

98 Object-glasses for the Microscope. [ Monthly, Microscopical

when touched with the moistened finger, it hisses smartly; a
morsel of tallow is then put on the rough-turned composition to
prevent adhesion, and the hot mould worked and rotated over it in
every direction till cold; when removed, the polisher will have
taken the exact form of the heated mould, and have acquired a
fine polish. For either convex or concave lenses the “pip” is
taken out as usual, and it is advisable to make a few concentric
scratches in the polisher if of large diameter.

As the mixture of crocus and putty-powder, recommended for
polishing, is apt to cling in these moulds if applied at once, I first
use the putty-powder alone; this cleans the hard polish off the
face, and the operation may then be continued with the mixture.

One great advantage of this composition, for a polishing mould,
is the decided way in which it maintains a true figure; for, unlike
any other of the kind, it undergoes a very slight degree of wear, so
that the face is always kept clean; and any number of lenses of
similar form and radius may be polished in the same tool without
having to alter or mend the figure, and perfect accuracy is the
result. This composition is now generally known, but Mr. James
Smith is the original discoverer of it. For the last degree of
polish, I sometimes rub a thin layer of pure soft beeswax in the
mould, and smooth it down to form with the now finished lens;
then a small quantity of the very finest-washed crocus is applied,
and the lens worked therein for about one minute. The extra
brilliancy of surface obtained this way is quite appreciable, and
well worth the pains bestowed, as the operation is not continued
long enough to run the risk of injuring the figure.

I have only now to give some directions for cementing the
lenses together. ‘The surfaces having been carefully cleaned, the
two lenses are laid on a hot plate, a drop of Canada balsam is
placed in the concave, the group of bubbles thrown up by the heat
removed by a brass point; with this the convex lens (which is
equally hot with the other) is lowered slantways into the balsam
so as to avoid bubbles, and the two lenses are pressed together ;
they are now lifted off the plate with a pair of curved forceps
held nearly horizontally, and shifted one-quarter round, and then
dropped down again. This is repeated a number of times, and the
two lenses being exactly of the same diameter, this operation must
set them concentric as a matter of course. - If the lens is a triple,
the opposite surface of the concave must be cleaned and the balsam
removed with strong alcohol (turpentine must not be used, as it
percolates the balsam too easily, and is apt to cause bubbles to
appear at the edges), and the same operation repeated as on the
other side. When the leng is cleaned with alcohol, and examined
edgeways with a magnifier, the three lenses will appear quite con-
centric, and should just pass into the cell without requiring any

‘Journal, Augtstben | Fottings from the Note-book, de. i

force; and if the workmanship has been correct—vzz. all the cells
turned true from one chucking, and the concaves of equal thickness
and concentric with their respective convex lenses, no errors of
centering can occur. The usual way of correcting this is by tilting
the lenses in the cells, in which they are cemented with Canada
balsam ; but at the best this is only to some extent substituting
one error for another.

oils ottings From the Note-book of a Student of Heterogeny.
, By Mercatre Jounson, M.R.C.S.

As the spokes of a wheel converge to the centre, so do the con-
current radii of evidence point to an axis of truth, either compara-
tive or absolute. | |

The following remarks are simply a description of some experi-
ments and observations made during the last two years in the
intervals of leisure in a life of practical medical labour. The
bearing of the facts upon the great questions of Speciology,
Epidemiology, and Nature’s scavenging, will be at once evident,
and will (it is believed) be found to run in a similar direction to
the facts recorded and opinions expressed by Hicks, Sachs, Itsigsohn,
Fries, Lindsay, Frau Luders, Pasteur, Pouchet, Archer, Lund, and
others. |

The observations, for the most part, have been made under a
magnifying power of 250 linear, while a few have required 700.

In November, 1867, some observations made under 700 linear
upon the tubules of Lyngbya muralis showed every variety (in-
creasing in size) of Monas lens (or what appeared identical with it),
to what when outside the tube appeared to be Convallaria in an
undeveloped state; green Gonidia, oval green bodies, and masses of
chlorophyll inside the tubule. |

The various bodies, with the exception of the chlorophyll
masses, Were in active motion; at the same time, I have frequently
witnessed masses of chlorophyll slowly traversing the vacuole of
the tube and, in some instances, the chlorophyll mass has given
out a blastoderm which assumed a transparent globular form as of
a vesicle, into which I have seen the small masses of chlorophyll
empty themselves. In addition to this, bodies apparently identical
with Monas lens have escaped from the chlorophyll blastoderm
into the terminal vacuole of the tubule, and there rotated after the
manner of monas, and in the course of time attached themselves to
the extremity of the vacuole. This I have witnessed in my re-
searches to find the bursting gemmules described by Dr. Hicks in

: H 2

100 Jottings from the Note-book [yoy ee aero.

his monograph on the Gonidia of Mosses.* The cells: escaping
from the chlorophyll mass are devoid of colour, and escape by
bursting of the blastoderm, and have at once independent rotating
movement on their own axis.

On August 31st, 1866, some yeast, flour, sugar, and water,
were placed in a bottle under a vessel containing ozonized air
(made by phosphorus), and gave off 35°2 per cent. of carbonic
acid ; while the same quantity of yeast, &c., was placed under a
jar of common air, and gave off 17°3 per cent. of carbonic acid.

By means of an air-sieve, I have collected distilled water
trickled over a glass plate into a trough, and found varymg quan-
tities of Monas lens besides other air-contents.

Parameecia subjected to the action of solution of potassic per-
manganate instantly cease to move, and assume a rust-brown colour,
while the purple of the original solution is destroyed (manganic
oxide ?).

Solutions of potassic permang. (one centimetre equal to -01 of
a grain of organic matter), when added to water from the air-
sieve, show discolorization varying from °01 to -19 to the pint.

Rain-water shows a greater discolorization than distilled water.

Distilled water sprayed through the air of my room shows
‘40 grain organic matter to the pint.

The following are the results of an experiment, March 5, 1868 :—

One pound cow-dung from centre of a recent deposit (kept in
stoppered bottle six weeks), mixed with 20 oz. distilled water, and
disposed of as follows :—

a. 2 0z. in clean bottle, with only a bubble of air, corked and sealed.
‘b. 1 oz. in 2-02. bottle, corked and sealed. :
c. 2 oz. in open glass beaker, with carbolic acid, placed in rather
dark room.
d. 2 oz. placed in a saucer, exposed to air in a rather dark passage.
e. 2 oz. placed in a round evaporating dish outside the window of
my room.
f. 2 oz. in square dish outside the window.
g. 9 oz. in tall glass jar outside the window.
e, f, g. Exposed to air and light and rain, examination showed the
following results :—
a. March 5th.—No moving gerins.
April 2nd.— __,, Bottle accidentally broken.
b. March 5th.— No moving germ.
,, 20th.—A few monads; Mucedo on cork.
,, 22nd.—Monads very numerous, movement saltatory ; no
Mucedo granules.
5, 26th.—Monads and Vibrions very abundant.
April 2nd.—Monads and Vibrions, all transparent, no green
colour.

* <Trans. Lin. Soc.,’ vol. xxiii., Tab. 58.

Mourne, Aue ea |. of a Student of Heterogeny. 101

April 17th.— Parameecium.

» 26th—A few monads; no Paramcecium.

June 24th Baars lightly corked) Oscillatoriz# (exposed to
light

¢. March 5th, 12th, 20th, April 2nd, 26th.—No moving germs on
any inspections.
d. March 5th and 7th—No moving germ.
,, L0th.—Several monads; one Paramcecium.
» L7th.—Numerous full-sized Paramcecia; monads of every
grade and size.
», 20th.—Monads large; Parameecia.
» 22nd.—Shape of Parameecia (like Euglena).
» 240th.—Parameecia, large and abundant ; cruia.
e. March 5th.—No moving germs.
» 12th—A few monads.
», 17th.—Monads numerous, very small.
55 20th.—Many small monads.

April 2nd.—On surface, green Gonidia (Euglena ?), very active ;
monads, few greenish; on side, green filaments ;
transparent slowly-amceboid bodies; one very
delicate Amoeba; green Gonidia; one gleo-
capsoid cell.

April 4th.—Many large green Gonidia nucleated.

» ¢th.—Dried up.
f. March 5th.—No moving germs.
April 6th.—Green Gonidia, large nucleated.
», tth.—Green Gonidia.
g- March 5th.—No moving germs.
»5 12th.—Monads.
», 1/¢th.—Monads very numerous.
5» 26th.—

April 13th, —T wo circular plants of Mucedo from a jar of paste

put into the liquid.
» 15th—Surface one mass of Vibrions; no wi Rae
17th.—Surface a moving mass of Vibri ions, side (exposed to
light), green Gonidia(?) very numerous, round,
all active.
» 21st.—Surface, Vibrions, no gonidia; side, green Gonidia(?)
rotating on their own axes.
» 22nd.—Side, thousands of green Gonidia (?).
5, 26th _—Numerous Kuglena, equal in size and appearance
to those grown in fields.

March 6th.—4 oz. distilled water placed in a glass beaker outside
window.
», 12th.—Several Gonidia and starch granules ?
» 20th.—A few monads.
5, 22nd.—A group of green Gonidia.

April 2nd.— A few monads, some black sediment, soot flakes, silex
and starch granules, and one green Gonidium.

102 Jottings from the Note-book [rae ee Re,

The following are the details of an experiment with infusion of
hay (cold one hour), which showed under nucroscope no moving
life, prepared May 25, 1868.

A. 1 oz. infusion of hay, in bottle, no air, corked and sealed.
B. 1 oz. a e 14-oz. bottle, 5 oz. air
Cr 307.2 4. a Lm bottle, no cork, in dark cupboard.
DD, 1002. ~.,; » glass beaker, outside window.
. 14 07. .., en long glass jar.
Gr oz = saucer in dark passage.
RESULTS.

A. May 25th—No moving life.
Aug. 20th.—No moving life.

B. May 25th—No moving life.
June 3rd.—Mucedo on cork, and few rotating monads in
liquid ; no moving life.

C, May 25th.—No moving life.
27th.— Filaments of Mucedo with fructules; elongated
cells; no movement.
30th.—Plant of Mucedo closing mouth of bottle; several
Paramcecia.
June 1st.—A new scum; innumerable Parameecia.
», 2nd.—Surface film one mass of moving Parameecia.
» 6th.—Parameecia and monads.
,» 22nd.—A green slime on surface.

D. May 25th—No moving life.
», 2th.—Filaments, cells, and discs of Mucedo; one or two
cells slightly moving.
5, 29th.—Monads very active at bottom.
» o0th.— % numerous.
June 1st.—Surface, a few monads; bottom, a mass of monads ;
one or two filaments.
,, 2nd.—Bottom, cells and filaments. <A bottle containing
Conferva rivularia has similar filaments of
Mucedo on surface.
,, ord.—Monads very active, smaller than in E.

99

39

» 6th— ,, and filaments, very small.
KE. May 25th—No moving life.
ee oes eens

sine —Innumerable monads. ,
June 1st.—Side to light, a mass of monads; surface, film of
monads; one Parameecium.
», 24nd.—Side, monads of every size and shape.
» 3rd.—Surface, filaments, with very active Parameecia.

G. May 25th.—No moving life.
5, 2th—Mucedo round and elongated; no filaments ;
monads very distinct and active.

ee of a Student of Heterogeny. 103

May 29th.—A few monads.
» 0th.—A large number of Paramcecia.
» olst.—Dried up.

The following extracts from notes taken at the time of obser-
vation.

April 15th, 1868.—In water containing Lyngbya I witnessed the
vacuole changing its position in Euglena cells.

April 28th.—Observed a green zoospore (Euglena), in a fluid con-
taining Lyngbya, change its shape, and the size and position of its
vacuole in the slow way of an Amceba; at times becoming almost free
from colour. Motion, slowly revolving on its axis; no cilia.

Another green zoospore, with amceboid change.

’ April 15th.—Numerous small zoospores in Lyngbya water, each
having a delicate green bag of chlorophyll rolling about in the cavity.

Witnessed two or three of the spots in Paramcecium coalesce into
one, and instantaneously disappear, as if by contraction of the cell-
wall; this I have frequently verified.

May 6th.— Found a Paramecium in Lyngbya water (April 27th),
containing several green Gonidia or chlorophyll particles.

May 11th.—Saw a Paramcecium burst in water enough to float
away ina granular stream. This I have frequently observed, but the
bursting always seemed due to the evaporation of the water used to
float the object. ,

May 20th.—Specimens of Paramcecium observed in Lyngbya water
(put up May 1ith).

May 20th.—I observed these changes: a globular and elongated
Paramcecium first attached, then separate, and finally the envelope of
the globular body seemed to burst, and the contents became absorbed
in the elongated object, and thus the two became one Parameecium.

June 12th.— Watched a small transparent body (Euglena) change
form from oval pyriform to globular. |

Aug. 20th.—In Lyngbya water (May 11th) saw numerous small
bodies (Euglena), all transparent.

May 23rd.—Witnessed two Paramecia struggling together for
several minutes.

April 17th. Saw two transparent Parameecia coalesce to form one.

April 21st. Among other forms of Paramcecium found, also a very
large number of Convallaria.

May 7th—Saw Paramecium from Lyngbya liquid (April 27th)
change form ; also another.

May 4th.—Found a ring of Euglena formed around the upper edge
of a bottle, into which Lyngbya was put April 27th.

May 6th.—Witnessed very slow changes in Euglena.

Saw Euglena of all shades, from green to colourless, in Lyngbya
water (put up one month).

May 10th.—Found Euglena with red spot in Lyngbya water
(April 27th).

May 11th.—Saw specimens of Euglena resembling large cells of
Oscillatoria.

104 A Supposed Mammalian Tooth [Monthly Microscopical

June 12th— Watched an Amceba from water containing Conferva,
and saw changes. Also several transparent globules, transformed to
Amceba.

April 28th.—Again witnessed the monads, freely moving in the
terminal vacuole of Lyngbya.

May 20th.—In water containing Euglena (put up May 11th) found
Oscillatoria, Paramcecia, Euglena, Amceba, Vibrions, green Gonidia
(Euglena ?), and diatoms.

Aug. 20th.—In a bottle containing Oscillatoria in water, found
a bright pink frond resembling Palmella cruenta, no purple cells.
Green Oscillatoria in all stages.

April 21st—Found (in a hothouse) a plant of Palmella cruenta
passing to green; red cells in red frond, but absent in green part, ~~

April 27th.—Another examination of a green part of a frond of
Palmella cruenta from a hothouse ; no red cells, all green.

May 11th.—On the green edge of a moist frond of Palmella
cruenta are very fine filaments of Oscillatoria.

The red cells gradually enlarging and assuming a green tinge.

May 11th.—On the surface of a liquid containing Lyngbya (May
9th) is a shining pellicle of Oscillatoria.

May 10th.—In a green rim on the surface of Lyngbya water (which
on May 4th consisted of Euglena), are now numerous filaments of
Oscillatoria.

April 21st.— Examined Oscillatoria, in which the vacuole seems in-
creasing in size, and the chlorophyll masses becoming more distinct.

May 6th.—Put a solution of Antimonii potass tartarate into two
bottles, one with only a globule of air, the other half-full of air.

May 18th.—Ligq. ant. pot. tart. in bottle half-full of air, contains
round cells, like monads (still) and Mucedo. |

Dec, 8th.—Opened the bottle with only a globule of air, no
Mucedo, amorphous film at bottom.

Dec. 8th.—Examined Glucosuria put up Nov. 18, 1868.

In bottle containing half air, found very large Mucedo.

In bottle with only a globule of air, no traces of Mucedo.

VILL.—A Supposed Mammalian Tooth from the Coal-measures.
By T. P. Barxas, F.G:S.

I nave recently, through the kindness of Mr. John Brown, Shield-
field, Newcastle-on-Tyne, been favoured with the examination of a
slide which he has prepared containing a tooth and a portion of
a jaw from the fossil remains of the Northumberland Coal-measures.
There is at present in Newcastle and its neighbourhood great
interest in the fossils of the Coal period, and several gentlemen have.
been engaged for a considerable time in preparmg and mounting
Coal-measure fossils for examination by the microscope. ‘Thousands
of sections have been made; and, besides those I have personally

St a from the Coal-measures, 105

prepared, I have examined a considerable proportion of those of my
co-workers, but up to the present time neither they nor myself,
so far as I have been able to ascertain, have seen a jaw with teeth
resembling that I propose to describe to your readers.

The portion of a jaw about to be described is the more interesting
because I have obtained from the shale which rests upon the Low
Main coal-seam in Northumberland a mandible which, so far as
it is exhibited in the matrix, has the appearance of being mamma-
lian; and although I have obtained many hundreds of jaws and
palate teeth, none of the specimens in my possession resemble it.
I am therefore not willing to rub it down for microscopic ex-
amination until I have been fortunate enough to obtain another
specimen, and am glad to have obtained the fossil to be described,
because, unlike all fish and reptile teeth I have found and mounted,
it possesses a long root or process by which it is inserted in the
dentigerous bone. ‘The teeth of fishes are anchylosed to the aveolar
borders of the jaws; the teeth of reptiles are introduced thimble-
like in series in the jaws; this specimen departs from both modes
of attachment, and to that extent at least has one of the leading
characteristics of a mammal tooth. As Ido not pretend to the
possession of an extensive knowledge of comparative anatomy or
comparative odontology, I take the liberty of asking through your
pages the opinions of your subscribers who have made comparative
anatomy a speciality.

The question is the more interesting, because if this be a
mammal tooth it is the first that has been discovered in strata so
low as the Carboniferous, and that hasbeen submitted to microscopic
examination. :

The length of the tooth is {;ths of an inch; it is inserted for
two-thirds of its length in the jaw.

Fig. 1 represents the specimen, natural size.

Fig. 2 illustrates the same fragment magnified ten diameters.
The wedge-shaped cavity in the centre of the tooth is the pulp cavity ;
it is rounded at the base: the walls of the tooth consist of dense
dentine, and are covered with a very thin coating of enamel. The
roots are two in number, and appear to be divided by a space for
the insertion of the nerves and arteries which supplied the tooth.
The spaces in the jaw marked x are filled by the black substance
of the matrix in which the specimen was found, and are probably
cavities that have previously been occupied by teeth. Fig. 3a
represents the apex of the tooth magnified 250 diameters ; the thin
outer coating is the enamel, the dark inner space is the apex of the
pulp cavity, the lies radiating from the dark space are the den-
tinal tubules which do not extend to the covering enamel. Fig. 4b
illustrates the right side of the tooth, half way between the aveolar
margin of the jaw and the apex of the tooth ; it is magnified 250

106 A Supposed Mammalian Tooth. re eee

diameters, and exhibits the dentigerous tubules extending from the
pulp cavity to the enamel, but not entering it; the tubules anasto-
mose, and occasionally divide dichotomously ; they are bolder in
this portion of the tooth than at the apex.

REN
\ \ \ \\
AN
\ \ \\ \ \
piss

i GN 4
at “ Ni a \
\
\\\
| ee

i\

\\

ny
VS

\

Fig. 5¢ represents a portion of the upper part of the roots of
the tooth near the point of junction of the two fangs, and is cha-
racterized by minute pittings, and irregular, broad, but faint
transverse lines ; it is also magnified 250 diameters.

Fig. 6d is that portion of the jaw near the poimt of sym-
physis, and between the roots of the tooth and the anterior
extremity of the jaw; it is a very open structure, not much unlike
the substance of the oral armature of some of the Ctenodi; and
covering the entire surface of the fragment of the jaw there are
numerous lacune or radiating bone-cells. Any information which
will lead to the identification of this apparently unique Coal-measure
fossil will be esteemed a favour.

Monthly Microscopical pees
Journal, Aug. 1, 1869. On Holtenia. 107

IX.—On Holtenia, a Genus of Vitreous Sponges. By Wrvinwe
THomson, LL.D., F.RB.S., Professor of Natural Sciences in
Queen’s College, Belfast.

Durine the deep-sea dredging cruise of H.M.S. ‘ Lightning’ in
the autumn of the year 1868, the dredge brought up, on the 6th
of September, from a depth of 530 fathoms, in lat. 59° 86’ N. and
long. 7° 20’ W., about 20 miles beyond the 100-fathom line of the
Coast Survey of Scotland, fine, grey, oozy mud, with forty or fifty
entire examples of several species of siliceous sponges. The mini-
mum temperature indicated by several registering thermometers,
was 47°°3 Fahr., the surface temperature for the several localities
being 52°°5 Fahr. |
The mud brought up consisted chiefly of minute amorphous
particles of carbonate of lime, with a considerable proportion of
living Globigerine and other Foraminifera, and of the “ coccoliths ”
and “ coccospheres,” so characteristic of the chalk-mud of the warmer
area of the Atlantic. The sponges belong to four genera; one of
them was the genus Hyalonema, previously represented by the
singular glass-rope sponges of Japan and the coast of Portugal,
and the other three genera were new to science. One of these
latter is the subject of the present paper.
Associated with the sponges were representatives, usually of a
small size, of the Mollusca, the Crustacea and Annelides, the Kchi-
nodermata, and the Coelenterata, with numerous large and remark-
able Rhizopods. Many of the higher invertebrates were brightly
coloured, and had eyes. |
_ Four nearly perfect specimens of the sponge described in the
memoir laid before the Royal Society were procured.

Hotrenia, n. g.* H. Carpentreni, n. sp.

_ The body of this sponge is nearly globular or oval. Normal
and apparently full-grown species are from 9” to 1’ 1” in length,
and from 7” to 9” wide. The outer wall consists of an open,
somewhat irregular, but very elegant network, whose skeleton is
made up of large separate siliceous spicules. These spicules are
found on the hexradiate stellate type, but usually only five rays are
developed, the sixth ray being separated by a tubercle. To form
this framework of the external wall, the four secondary branches
of the spicule spread on one plane, the surface of the sponge, while
the fifth or azygous branch dips down into the sponge-substance.

* The genus is named in compliment to Mr. Holten, Governor of the Faroe
Islands, and the species is dedicated to Dr. W. B. Carpenter, V.P.R.S., with whom
the author was associated in the conduct of the scientific expedition.

108 On Holtenia, a Genus poe ge oan
This arrangement of the spicules gives the outer surface of the
sponge a distinctly stellate appearance, the centres of the stems
being the point of radiation of the secondary branches of the
spicules. ‘These quinque-radiate spicules measure about 1”"°5 from
point to point of the cross-like secondary branches, and the length
of the azygous arm is from 7'"°5 to 1”.

Smaller stars, formed by the radiation of smaller spicules of the
same class, occupy the spaces between the rays of the larger stars.

The rays of each star bend irregularly, and meet the rays of
the spicules forming the neighbouring stars. The rays of the dif-
ferent spicules thus run along for some distance parallel to one
another, and are held together by a layer of elastic sarcode, which
invests all the spicules and all their branches. Between the rays
of the spicules, over the whole surface, the sarcode forms an
ultimate and very delicate network, its meshes defining and sur-
rounding minute inhallant pores.

At the top of the sponge there is a larger osculum, about
3” in diameter, which terminates a cylindrical cavity which passes
down vertically into the substance of the sponge to a depth
of 5”5”. The walls of this oscular cavity are formed upon the
same plan as the external wall of the sponge, and the stars, which
are even more conspicuous than those of the outer wall, are due to
the same arrangement of spicules of the same form. The ultimate
sarcode network is absent between the rays of the stars of the
oscular surface.

The sponge-substance, which is about 2" in thickness be-
tween the oscular and outer walls, is formed of a loose vacuolated
arrangement of bands and rods of greyish consistent sarcode, con-
taining minute disseminated granules, and groups of granules of
horny matter, and endoplasts.

Towards the outer wall of the sponge the sarcode trabecule are
arranged symmetrically, and at length they resolve themselves into
distinct columns, which abut against and support the centres of
the stars, leaving wide open anastomosing channels between them.
The garcode of the outer wall, and that of the wall of the oscular
cavity, is loaded with minute spicules of two principal forms,
quinque-radiate spicules with one ray prolonged and feathered,
and minute amphidisci.

Over the lower third of the body of the sponge, fascicles of
enormously long delicate siliceous spicules pass out from the sarcode
columns of the sponge-body in which they originate, through the
outer wall, to be diffused to a distance of not less than half-a-metre
in the mud in which the sponge lives buried ; and round the osculum
and over the upper third of the sponge, sheaves of shorter, more ~
rigid spicules project, forming a kind of fringe.

I refer all the sponges which were found inhabiting the chalk-

3 eas of Vitreous Sponges. 109

mud to the order Porifera Vitrea, which I have defined in the
‘Annals and Magazine of Natural History’ for February, 1860.
This order is mainly characterized by the great variety and
complexity of form of the spicules, which may apparently, with
scarcely an exception, be referred to the hexradiate stellate type, a
form of spicule which does not appear to occur in any other order
of sponges. The genus Holtenia is nearly allied to Hyalonema,
and seems to resemble it in its mode of occurrence. Both genera
live imbedded in the soft upper layer of the chalk-mud in which
they are supported,— Holtenza by a delicate range of siliceous fibres,
which spread round it in all directions, increasing its surface
without materially increasing its weight; Hyalonema by a more
consistent coil of spicules, which penetrates the mud vertically and
anchors itself in a firmer layer.

It appears to me and to Dr. Carpenter, who have had our
attention specially directed to this point as bearing upon the con-
tinuity and identity of some portions of the present calcareous
deposits of the Atlantic with the cretaceous formation, that the
vitreous sponges are more nearly allied to the Ventriculites of the
chalk than to any recent order of Porifera. We are inclined to
ascribe the absence of silica in many ventriculites, and the absence
of disseminated silica in the chalk generally, to some process, pro-
bably dialytic, subsequent to the deposit of the chalk, by which
the silica has been removed and aggregated in amorphous masses,
the chalk flints.

The vitreous sponges along with the living Rhizopods and other
Protozoa which enter largely into the composition of the upper
layer of the chalk-mud, appear to be nourished by the absorption
through the external surface of their bodies of the assimilable
organic matter which exists in appreciable quantity in all sea-water,
and which is derived from the life and death of marine animals
and plants, and, in large quantity, from the water of tropical rivers.
One principal function of this vast sheet of the lowest type of
animal life, which probably extends over the whole of the warmer
regions of the sea, may probably be to diminish the loss of organic
matter by gradual decomposition, and to aid in maintaining in the
ocean the “ balance of organic nature.”—Abstract of a paper read
before the Royal Society at its last meeting, June 23rd.

Monthly Mi ical
( 1 1 0 ) Journal: AME. Le 1369.

NEW BOOKS, WITH SHORT NOTICES.

Entozoa: being a Supplement to the Introduction to the Study of
Helminthology. By T. Spencer Cobbold, M.D., F.R.S. London:
Groombridge, 1869.—Those of our readers who already possess
Dr. Cobbold’s larger treatise will be glad to see this supplement
to so excellent a treatise on Entozoa. In some respects it brings
down the original work to the present date, but in others it may
be regarded as an independent work containing some valuable
special chapters on questions connected with parasites. The section
devoted to the history of the discovery of Trichina is very in-
teresting. In it the author collates the evidence bearing on the
point under discussion, and we think shows very satisfactorily
that Mr. Paget must be regarded as the original discoverer of
this entozoon. His concluding remarks are very significant, and
allude indirectly to the tendency on the part of certain very
distinguished biologists to slur over the work of their fellow-
countrymen. They refer the reader in search of fuller infor-
mation to the original letters on the subject, the sources of which
are stated in the copious bibliography which the author appends
to the volume, and they terminate in the following pregnant
sentence, “There are persons on this side the Channel who
systematically ignore the labours of their own countrymen.”
The second chapter is also of interest, as it records a number
of experiments (twenty-nine) made on birds and mammals
with the muscles of a Trichinised subject. These experiments
bear out those made by Pagenstecher and others, in proving
that the Trichine: do not find a favourable nidus for their deve-
lopment in the intestines of birds, or at least do not pene-
trate the blood-vessels of the alimentary canal in these animals.
A good many of the trials on mammals failed in giving absolute
results, but some of them were so distinctly successful that
they leave no doubt as to the cause of the Entozoa. The chapter
of the work which will most interest the microscopist is that
which refers to the peculiar bodies which were found in the flesh of .
animals which died of the rinderpest. Some histologists regarded
these as being in some way or other connected with this disease,
but Dr. Cobbold gives numerous observations to show that they
are as often present in healthy as in diseased animals, and he
cites various experiments made upon himself to show that they are
perfectly harmless. He regards these bodies as Psorospermie, and
gives the following account of their microscopic characters :—“ The
bodies are enclosed in a well-defined transparent envelope, and
even under low magnifying powers their contents exhibit more or
less distinct indication of segmentation. In some specimens the
segments display themselves as a distinct cell-formation, the con-
tents of each individual cell being uniformly granular. Hven
under the }-inch objective the contained granules are clearly

Mourne Aue eee | PROGRESS OF MICROSCOPICAL SCIENCE. 111
visible, and on rupturing the sac their peculiar characteristics are
at once manifest. Hach granule or corpuscle represents a pseudo-
navicel, all of them displaying a tolerably uniform size, which I
calculated to average 3,55 of an inch in diameter. Some of the
corpuscles were round, others oval, several bluntly pointed at one
end, many curved and fusiform, not a few being almost reniform ;
under the 41-inch objective highly-refracting points or nucleoli
were fairly visible in their anterior, but on employing the 4th, I
made out nothing more respecting the contents of the corpuscles.”

The other chapters will be found full of important matter, and
the list of authorities, bibliography, and index, show that details
have been carefully attended to in preparing the work for the
press. The author’s remarks on “ Organic Individuality,” which
he considers from an entozoologic point of view, are suggestive ;
but we think the system of division is pushed a little too far. We
question very much the advisability of employing so many dis-
tinct technical terms to designate the numerous stages in the life-
history of certain Entozoa. Helminthologists will find Dr. Cobbold’s
book a very complete supplement to his former investigations,

PROGRESS OF MICROSCOPICAL SCIENCE.

The Nervous and Vascular Systems of Limulus.—M. Alph. Milne
Edwards has been investigating into the anatomy of Limulus, and he
has discovered some very remarkable facts in regard to the structure
of this singular crustacean. Ina paper which he communicated to the
Société Philomathique de Paris on the 26th of June, he stated that
the researches of Van der Hoeven and Gegenbaur, while excellent in
their way, left nevertheless a great deal to be done still. His own
researches had been made upon the animals in the great Aquarium at
Havre, and had been directed especially to the circulatory apparatus,
_ which he says is most remarkable. He has found that a portion of
the blood on leaving the heart passes directly through a vessel with
resisting walls, and which includes nearly the whole nervous centres,
and even some of the nerves, especially those of the eyes and foot-jaws,
in such a way that the ultimate nerve-fibres, which are very loosely
connected, are completely bathed in blood. In point of fact, instead
of having the nerves accompanied by arteries, the arteries actually
enclose the nerves. He also notes the presence of very numerous
anastomoses between all parts of the arterial system. Finally, he
states that the mode of origin of the nerves shows that the small
anterior foot-jaws of these animals are the analogues of the antenne
of insects and crustacea, and the chelicers of Arachnida. From these
facts and others, he is disposed to rank Limulus among the spiders. (!)

Microspectroscopic Characters of Opals——In the ‘ Proceedings of
the Royal Society’ for June is published Mr. Crookes’ interesting

112 PROGRESS OF MICROSCOPICAL SCIENCE. [Monthly Microscopical

paper on this subject, accompanied by numerous woodcuts. ‘The
following are descriptions of some of the more remarkable spectra
given by a number of choice opals:—No. 1 gives a single black band
in the red. When properly in focus this has a spiral structure.
Examined with both eyes it appears in decided relief, and the arrange-
ment of light and shade is such as to produce a striking resemblance
to a twisted column. No. 2 gives an irregular line in the orange.
Viewed binocularly, this exhibits the spiral structure in a marked
manner, the different depths and distances standing well out; upon
turning the milled head of the stage-adjustment, so as to carry the
opal slowly from left to right, the spiral line is seen to revolve and
roll over, altering its shape and position in the spectrum. It is not
easy to retain the conviction that one is looking merely at a band of
deficient light in the spectrum, and not at a solid body, possessing
dimensions and in actual motion. No. 3 gives a line between the
yellow and green, vanishing to a point at the top, and near the bottom
having a loop, in the centre of which the green appears. Higher up,
in the green, is a broad green band, indistinct on one side and branch-
ing out in different parts. No. 4 gives a broad, indistinct, and sloping
band in the blue, and another, still more indistinct, in the violet.
No. 5 gives a band in the yellow, not very sharp on one side, and
somewhat sloping. Upon moving the opal sideways, it moves about
from one part of the yellow field to another. In one position it
covers the line D, and is opaque to the sodium-flame of a spirit-lamp.
No. 6 gives a curiously shaped band in the red, very sharp and black,
and terminating in one part at the line D. In the yellow there is a
black dot. The spectrum of this opal showed by reflected light
intensely bright red bands, of the shape of the transmission bands.
On examining this opal with a power of 1 inch, in the ordinary
manner, the portion giving this spectrum appeared to glow with
intense red light, and was bounded with a tolerably definite outline.
Without altering any other part of the microscope, the prisms were
then pushed in so as to look at the whole surface of the opal through
the prisms, but without the slit. The shape and appearance of the
red patch were almost unaltered ; and here and there over other parts
of the opal were seen little patches of homogeneous light, which, not
having been fanned out by the prisms, retained their original shape
and appearance. No.7 gives a black patch in the red, only extending
a little distance, and a line in the yellow. On moving the opal the
line in the red vanishes, and the other line changes its position and
form. No. 8 gives the most striking example of a spiral rotating line
which I have yet met with. On moving the opal sideways the line
was seen tostart from the red and roll over, like an irregularly shaped
and somewhat hazy corkscrew, into the middle of the yellow.

Effects of Induction-currents on Amoeba diffluens and Arcella vulgaris.
—Some curious experiments have been made on these animals by M.
T. W. Engelmann, and were recently reported to the Royal Academy
of Sciences of Amsterdam. The animals were placed in a gas-
chamber contrived with electrodes for the purpose, and the results
were watched with the microscope. The following are some of the

Mourns, Aug. 1 189] PROGRESS OF MICROSCOPICAL SCIENCE. 113

results :—The course of the phenomena following the irritation of a
single interrupted discharge from the coil is, says the author, deter-
mined by the intensity of the current and the condition of the proto-
plasm previous to the excitation. When the Ameba is acted on by
the current, it is seen—when the animal has an elongated form, and
moves with a regular velocity (0°01 to 0°2 mm. per second)—that the
following events occur. A. In Case of Feeble Irritation—After a
short period of latent action, or even very rapidly, there is a sudden
slackening or suspension of movement on the part of the granulations
of the protoplasm, without any appreciable change of form on the
part of the animal. In a few seconds more there is a gradual re-
establishment of the current, and of the displacement of the granu-
lations in the primary direction, without change of form on the part
of the animal. Total duration of action, five seconds, maximum.
B. In Case of a Medium Degree of Irritation—Period of latent action
hardly perceptible. Immediate arrest of granulations without change
of form on part of animal. In about three seconds more there is a
change of form (contraction) on the part of the animal, consisting in
shortening and thickening of the Amcba (assumption of spherical
form). During these changes the anterior part of the animal remains
fixed by adhesion to the glass. ‘The assumption of the spherical form
is the more complete and rapid as the current is stronger. The time
of contraction in case of feeble irritation may be about two seconds.
The maximum of shortening may last for some time. Moreover, when
the irritation has been very feeble, the granulations immediately
recommence their circulation, and produce lateral expansions of the
protoplasm. One of these expansions progressively increases, till it
absorbs the total mass of the protoplasm, which thus being restored to
the primitive elongated form, begins to move with regularity. The
total duration of action is from about ten to fifteen seconds, C. In
Case of a Powerful Irritation —Here there is immediate arrest of the
course of the granulations and commencement of contraction, which in
about two seconds produces the maximum degree of shortening, that is to
say, the more or less complete spherical form. After from half a minute
to a minute and a half there is a re-establishment of the movement of
the granulations, and formation of lateral expansions. In about two
minutes the original condition of things is restored. When the
Amoebe experimented on are large and flat, and provided with short
expansions, the effect of irritation differs according as a single shock
or a series of shocks is given. The first action still consists in an
arrest of the movement of the granulations, and of a very slight con-
traction. Soon after the Amcba becomes elongated nearly to a
cylinder, and moves very rapidly in one direction, almost without
change of form. Meanwhile, if the irritation is renewed, there is
again an arrest of the granulations, and contraction takes place. The
phenomena exhibited by Arcella vulgaris under the influence of
electricity are, says M. Engelmann, best seen when the animal
encloses a number of air-bubbles at the moment of excitation. The
specimens best suited for observations of this kind are those which
swim at the surface of a drop of water, the dorsal surface being next
VOL. Ii. I

114 PROGRESS OF MICROSCOPICAL SCIENCE. [ Monthly, Microscopical

the glass which forms the upper part of the gas-chamber. In such
cases the air-bubbles preserve their size and form for a long while; at
the same time the protoplasm is extremely mobile, and its expansions
are frequently disappearing, like a dissolving-view. The form of the
air-bubbles is irregular, being never perfectly spherical. When a
current—that formed by making contact—is passed through the drops,
the immediate, or nearly immediate, result is, that the bubbles of air
become perfectly spherical, or—in places where the “test” prevents
them—spheroidal, and the protoplasm withdraws a little from the
inner surface of the “test.” After a while—from one to ten or
twenty seconds—the form of the vesicles becomes irregular, the proto-
plasm recommences its movements, and the protuberances reappear.
After some minutes further, the bubbles of air become smaller and
smaller, and the Arcella descends. Soon, however, in about half a
minute, the bubbles become enlarged again, and the Arcella reascends.
M. Engelmann says the experiment may be repeated several times
with the same results. The author concludes his remarks by saying :
—“From the fact of the bubble of air becoming spherical during the
contraction due to the electrical action, it follows that the protoplasm
during its contraction obeys the mechanical laws of liquids. The air-
bubbles in becoming spherical do not apparently alter their volume.”

The Development of Acaride.—At a recent meeting of the Royal
Academy of Belgium, M. Van Beneden read a letter which he had
received from M. Bessels, of Stuttgard, relative to the above subject.
The substance of the letter was briefly as follows :—“'The embryogeny
of the Arthropoda had been very little studied up to the year 1863.
But since the appearance of Weissman’s work on the development of
the Diptera, the subject has received more attention, and has been
especially brought out by the memoirs by Mecznikow and Dohrn; and
lately I have received from my friend Dr. Alexander Brandt, of St.
Petersburg, a memoir published by the Academy on the subject of the
development of the Libellulide and Hemiptera, in which the author deals
especially with the embryonic membranes. For some time I have devoted
attention to the development of Ataw, Phytopus, Sarcoptes, Tetranychus,
and other kindred genera.” 'The writer then observes that his observa-
tions entirely agree with those of Claparéde, published in a late number
of Siebold and K6lliker’s Zeitschrift, and he states that his results do not
accord with those of M. Van Beneden. “I have,” he says, “been equally
unsuccessful, with Claparéde, in not finding the germinal vesicle in
ova recently deposited, as you have announced in your researches on
the development of Atax ypsilophorus (p. 18). Doubtless it escaped
my observation owing to the deep colour of the vitellus. Having
never observed the ovarian eggs, it seems to me impossible to decide
whether the membrane which surrounds the vitellus is a vitelline
membrane or a chorion. I have been fortunate enough to observe the
mode of formation of the blastoderm, which both you and Claparede
missed. It would be hard to say how soon the blastoderm appears
before the ovum leaves the oviduct, since the deposition of the ova
has not been observed. In ova taken from the mantle of Umo and
Anodon I have seen the blastoderm appear in from one to two days.
If one of these ova be opened cautiously in a solution of one per cent.

ee Se ee

Mourne! Aug 1 ase9,.| PROGRESS OF MICROSCOPICAL SCIENCE. 115

of bichromate of potass, it will be seen that the blastoderm does
not exhibit itself over the whole surface of the egg, but that it appears
in islets. On account of the deep colouration of the vitellus it is
impossible to view this phenomenon satisfactorily without destroying
the ovum. After the blastoderm has extended around the yolk, the
embryonic membrane detaches itself from it. It is this membrane
which you have regarded as formed by the division of the primitive
envelope of the ovum, and which Claparéde has designated under the
name of deutovum. I consider it to be the homologue of the larval
membrane [Larvenhaut]| of Crustacea, and this is evidently the homo-
logue of the amnios of insects. I hope to demonstrate this more fully
ina memoir on the amnios of Arthropoda which I hope to publish
soon. It isina short time after the formation of this embryonic mem-
brane that we see appear between it and the blastoderm the first
amceboid cells that Claparéde thought arose at a later period. When
in my work I designated these amceboid corpuscles under the name of
blood-globules, I desired merely to indicate their relation to the cells
of the blastoderm which at the date of the appearance of these
hem-amebe are the only cellular formations of the ovum. It seems
to me that we shall have to admit two modes of origin of blood-cor-
puscles. In certain ova that I have watched through their entire
period I have never seen any of these amceboid cells penetrate into
the interior of the ovary. Claparéde asks if you have not taken the
parasites of Anodon for those of Unio, or, rather, if they are not the
same animals which live in Belgium on Anodon, and in Geneva on
Unio. In commencing my researches I placed a hundred Anodons
collected from the neighbouring pools in a locality with running
water, where I subsequently placed the Unio batavus. Four weeks
after the two had been placed side by side, I found—as I have since
frequently done—the parasite of Unio on Anodon, and vice versd. It is
hardly possible to confound the two parasites, as those of Unio have
five suckers on each side of the ventral orifice, and those of Anodon
have from thirty to forty.” Such being the substance of M. Bessels’
letter, the following is that of M. Van Beneden’s reply :—“'The
disagreement which the writer points out has no real existence, since I
declared distinctly that I had examined only the ovarian eggs. What
I said was, ‘the germinal vesicle is relatively larger as the egg is
younger. Jam astonished that MM. Bessels and Claparéde did not
perceive that I spoke of the composition. of the ovum before deposi-
tion. As to the Atax, which M. Claparéde supposes to proceed from Unio
rather than Anodon—which I shall send him alive if he wishes—all
those used in my researches were taken from the same locality in the
neighbourhood of Louvain, and where I have never seen any but
Anodon. For the rest, M. Bessels’ observations show that the same
Atax may live on both mollusks. I would remark, in conclusion, that
the amceboid cells which appear around the blastoderm seem to be
perfectly analogous to those pretended parasites which appear in the
same conditions on different mollusks, and which Nordmann* has
named Cosmella hydrachnoides in Tergiupes Edwardsit.”
* ¢ Ann. des Sci,’ 1846, vol. v., 3™° Série.

2 : Monthly Microscopical
116 NOTES AND MEMORANDA. Tourn die aes,

NOTES AND MEMORANDA.

Preserving Insects.—A writer in one of the American journals
states that the ravages of the beetle Dermestes lardarius may best be
arrested by placing a few crystals of carbolic acid in the cases. He
states that the evaporation from them will kill all insects in the vicinity.

Trichina spiralis—A Prize Essay.—The following notice of the
Boston Natural History Society may interest those engaged in the
investigation of Entozoa :—By the provisions of the late Dr. William
J. Walker’s foundation, two prizes are annually offered by the Boston
Society of Natural History for the best memoirs, written in the
English language, on subjects proposed by a committee appointed by
the council. For the best memoir presented, a prize of sixty dollars
may be awarded; if, however, the memoir be one of marked merit,
the amount may be increased, at the discretion of the Committee, to
one hundred dollars. For the memoir next in value a sum not ex-
ceeding fifty dollars may be given; but neither of these prizes are to
be awarded unless the papers under consideration are deemed of
adequate merits. Memoirs offered in competition for these prizes
must be forwarded on or before April 1st, of the year specified below,
prepaid, and addressed “ Boston Society of Natural History, for the
Committee on the Walker Prizes, Boston, Mass.” Hach memoir
must be accompanied by a sealed envelope enclosing the author's
name, and superscribed by a motto corresponding to one borne by
the manuscript. Subject of the Annual Prize for 1870, “'The repro-
duction and migration of Trichina spiralis.”

Browning’s Miniature Spectroscope—We have had this marvel-
lously cheap and handy pocket-spectroscope in use for some time, and
find it answer most of the purposes for which the spectroscope is
employed. It is especially useful for the examination of the absorp-
tions produced by certain coloured (and colourless) fluids. We
especially commend it to the physician. In the out-patients’ room of
an hospital, where it is difficult to employ a microscope for the detec-
tion of blood in urine, this little instrument of Mr. Browning’s will
afford the means of diagnosis almost in a moment. In optical quali-
ties it leaves—considering its small size, which enables it to fit in
the waistcoat pocket—little to be desired.

Poin PROCEEDINGS OF SOCIETIES. a ALL

PROCEEDINGS OF SOCIETIES.*

QuEKEeTr MicroscopicaL Cius.t

On the 23rd of June, the annual excursion of the club took place.
Five-and-twenty members proceeded by train to West Humble, in
Surrey, where they alighted. They strolled thence over Box Hill
and the adjacent country ; the exceeding fineness of the day greatly
enhancing the beauty of the scenery in which the locality abounds,
and adding materially to the enjoyment of the excursionists.

After having rambled to their heart’s content, they returned to
Leatherhead, where they were joined by several other members of
the club with their friends, and the whole, numbering fifty-one, sat
down at 6 o’clock to an excellent dinner provided by mine hostess of
the “Swan,” the chair being occupied by the President. A must
social and agreeable evening was spent, much satisfaction being
expressed with the arrangements made by the excursion committee
(Messrs. Arnold, Gay, Reeves, and Suffolk), to whom the cordial
thanks of the guests were given.

The Fourth Annual General Meeting was held on Friday evening
the 23rd July, in the Library of University College; Mr. Arthur E. |
Durham, President, in the chair. A report was read which showed that
142 members had been elected since the last annual meeting, making
a total of 512. The Treasurer’s report showed that the finances were
in a very satisfactory condition. In vacating the chair, which he had
filled for two years, the President delivered a highly impressive
address, which was listened to with marked attention throughout.
The following gentlemen were elected to fill the offices named during
the ensuing year :—President, Mr. P. Le Neve Foster; Vice-Presi-
dents, Dr. R. Braithwaite, Mr. W. M. Bywater, Mr. A. E. Durham,
and Mr. H. F. Hailes; Members of Committee, Mr. T. Crooke, Mr.
B. T. Lowne, Mr. S. J. M‘Intyre, and Dr. J. Matthews; Treasurer,
Mr. R. Hardwicke; Hon. Secretary, Mr. T. Charters White; Hon.
Secretary for Foreign Correspondence, Mr. M. C. Cooke. A paper
“On the Ratio-micropolariscope,” by Mr. James J. Field, its inventor,
was read, at the conclusion of which the instrument was exhibited.
al members were elected, after which the proceedings termi-
nated.

BricHTON AND Sussex Natrurat History Socrery.

July 8. The President, Mr. Glaisyer, in the chair. Papers were
read by Mr. T. W. Wonfor, Hon. Sec., “On the 15th Annual Excur-

* Secretaries of Societies will greatly oblige us by writing out their reports
legibly—especially the technical terms—and by “underlining” words, such as
specific names, which must be printed in italics. They will thus ensure accuracy
and enhance the value of their proceedings.—Eb. M. M. J.

+ Report supplied by Mr. R. T. Lewis.

1 Monthly Mi ical
118 PROCEEDINGS OF SOCIETIES. Le ees

sion,” and by Mr. J. Robertson on Professor Owen’s General Conclu-
sions, in which his ideas on the origin of species and life were
criticized.

It was resolved that the Hon. Secretaries be instructed to com-
municate with the town authorities, and see in what way the co-opera-
tion of the Society would be most effective to induce the British
Association to visit Brighton.

BrramincHamMm Natura History anp MicroscopicaAL Sociery.*

The following papers were read at the meetings of this Socicty,
held during the month of May :—

By Mr. A. Simeox, “ On the Geology of North Gloucestershire.”

By Mr. E. J. Chitty, “On the Desmidiacex, with Notes on their
Collection and Cultivation ;” being an account of observations as to
their mode of growth and reproduction extending over the past four
years (for which period the author has successfully maintained a
considerable number of species in a healthy state under artificial
conditions), together with practical hints as to the best means of
collecting, cleaning, and preserving them.

By Mr. E. Myers, “ Notes on the Gulf Stream.”

By Mr. EH. Simpson, “On Insect Anatomy and Classification,” a
valuable practical paper, commencing with an analysis of the various
systems which have been adopted by different naturalists ; and pro-
ceeding to a description of external insect anatomy and its applica-
tion to the classification now generally adopted. The paper was
illustrated by a fine collection of specimens and of microscopic pre-
parations.

At the same mecting the secretary of the geological section gave
an account of a very successful excursion of its members to the
villages on the west side of Wolverhampton, resulting in a large
addition to the map of the glacial features of the district, upon the
construction of which on a large scale the section is now engaged,
and in the discovery of a considerable number of crystallized minerals
imbedded in boulders, and including hornblende, garnets, &c.

During the same month most departments of Natural History
have been well represented on the evenings devoted to the exhibition
of specimens—the season of course favouring the display of botanical
treasures. These comprised Smyrnium olusairum and Knappia agro-
stidea from Jersey, contributed by Mr. C. Adcock; Saxifraga tridac-
tylites from Knowle, and Gymnogramma leptophylla from Jersey,
Narcissus biflorus and other plants from Moseley, by Mr. Crofts ;
Paris quadrifolia from Alvechurch, by Mr. Morley; Thlaspi perfo-
liatum from Tetbury, the rare moss Amblyodon dealbatus, &c., from
Sutton, by Mr. Bagnall; by Mr. J. Lamb, Fritillaria meleagris from
Reading; by Dr. Griffiths, Opergrapha amphotera from Cader Idris,
and many other rare lichens; by Mr. Marshall, Orchis muilitaris,
O. ustulata, Ophrys muscifera, and O. aranifera, from Wye Downs; and
a great variety of other specimens either absolutely or locally rare.

* Report furnished by Mr. A. W. Wills..

eae ane eo PROCEEDINGS OF SOCIETIES. 119

Conchology was represented by Mr. Nelson, who produced a fine
collection of foreign land-shelis; and Mr. Tye, who exhibited a
number of freshwater shells from various localities in North America ;
and others. The entomological specimens were gocd, but small in
number on account of the unusual inclemency of the weather. The
zoological comprised Halithea aculeaia from Torquay, sent by Mr.
W. H. Harper; a very complete collection of British birds’ eggs, by
Mr. W. Wilson; an excellent and well-arranged cabinet of insects,
by Mr. Simpson, &c.

The interest in the microscopical branch of the Society has been
fully sustained, and from a large number of specimens exhibited by
its members the following may be mentioned :-—

By Mr. Bolton, a fine collection of Rotatoria, including Dinocharis
pocillum, Huchlanis triquetra, Brachionus urceolaris, Syncheta pectinata,
Limnias ceratophylli, and other species; by Mr. Graham, Huglene,
active and encysted; by Mr. Parsons, various species of Vaucheria
and Batrachospermum, very finely in fructification; by Mr. Tye, the
beautiful Polyzoon, Bowerbankia imbricata ; by Mr. Shoebotham, a
singularly fine series of preparations produced by a new mode of
manipulation, and including tissues showing the stomata of Ilex
aquifolium, Agraphis nutans, Agave Americana, and many other plants;
by Mr. Wills, Vaucherta Diilwynnit, V. ovoidea, V. ornithocephala, V.
repens, V. sessilis, Closterium acerosum in conjugation, and a remark-
ably rich gathering of Volvox glebator.

MicroscoricaAL Society or LIvERPOOL.

The sixth ordinary meeting was held at the Royal Institution, on
Tuesday, lst June, Dr. Nevins, President, in the chair. A lecture
was delivered by Dr. Thomas Inman, one of the Vice-Presidents, on
the Natural History and Microscopical Characters of Hairs. Dr.
Inman first called attention to the utility of prosecuting any micro-
scopic or other subject of study as far as possible, remarking that
such investigation showed that in almost every animal and vegetable
structure there was general resemblance, but individual difference.
The tongues of the mollusca were marked in the same way as regards
plan, but in detail each variety had a tongue so peculiar to itself that
a doctor might say to 1t, Show me your tongue, and I will tell your
name. A similar statement applies to hairs. The observer readily
distinguishes butterflies and moths as such by their scales, and the
birds by their feathers ; but a closer observation enables him to name
the particular genus from which a particular scale or feather comes.
It would be impossible in a shori essay to describe all forms of those
appendages of the skin to which the names of scales, feathers, hairs,
wool, &c., had been given. He therefore would confine himself chiefly
to a description of the general characters of animal hairs. The most
simple form of hair was found in butterflies and the insect world. In
them was to be seen a long hollow pointed cylinder attached to and
forming part of the skin. This might be compared to the central
stem of a bird’s wing-feather. In some creatures this stem became

120 BIBLIOGRAPHY. Mou we Oe
branched, and in others the offshoot became still further branched, as
in pinion feathers, where the original branches had curved branchlets
which intertwined with each other so as to prevent their separation.
In others the simple hair became forked like the letter Y, and the
space between the branches became filled up to form a scale. In the
hair of mammalia there were three parts to be noticed—an outer
scaly covering (a continuation of the epidermis), a fibrous material
growing from a special matrix, and somewhat analogous to nails and
hoofs, and a central cellular growth.

(To be continued.)

BIBLIOGRAPHY.

Zur nahern Keuntniss d. Proventriculus und der Appendices ven-
triculares bei den Grillen und Laubheuschrecken von Herrn Dr. von

Graber. Wien. Gerold’s Sohn.

Beitrage zur Entwicklungs-geschichte der Pflanzenorgane, von
Herrn H. Leitgeb. Wien. Gerold’s Sohn.

Bryozoi pliccenici italiani, von Dr. A. Manzoni. Wien. Gerold’s
Sohn.

Cryptogamen-Herbarium der thuringen’schen Staaéten von Herrn
W. O. Miller. Gera Griesbach.

Die Hirnwindungen des Menschen, etc., von Herrn Prof. Alex.
Kicker. Braunschweig. Vieweg & Sohn.

Mikroskopische Untersuchungen der Vesuv-laven vom Jahre, 1868.
Von Herrn F. Kreutz. Wien. Gerold’s Sohn.

L’Ecrevisse, moeurs, reproduction, éducation; par M. P. Carbon-
nier. Paris. Lachaud.

Etude sur un parasite de la chenille du Liparis dispar; par M.
Charault. Le Mans. Monnoyer.

Nouvelles considérations sur les maladies des vers-a-soie, et sur les
épidémies en général; par M. E. Le Moyne. Marseille. Arnaud.

Note pour servir 4 la faune de la Gironde, contenant la liste des
animaux marins, dont la présence a Arcachon a été constatée pendant
les années 1867 et 1868: par M. A. Lafont. Bordeaux. Degréteau.

Rapport sur Vostréiculture & Arcachon, Hayling, et Trieste; par
M. le docteur Soubeiran. Paris. Victor Masson.

eee

THE

MONTHLY MICROSCOPICAL JOURNAL.

SEPTEMBER 1, 1869.

I.—Micro-spectroscopy.— Results of Spectrum Analysis.
By Jasez Hoae, F.L.8., Hon. Sec. R.M.S., M.R.C.S., &e.

(Read before the RoyaL Microscopical Sociery, June 9, 1869.)

WHEN we look back upon an important discovery in science, how
frequently it occurs that a great fact wholly unexpected is pre-
sented to us, and even unconnected with the subject which had
engaged the attention of the explorer. It has been so with
spectrum analysis, the origin of which may fairly be referred to
Newton’s discovery of the composition of the solar spectrum. This
physical phenomenon, made known to the world more than two
hundred years ago, led to the inquiries which step by step have
conducted us to the most delightful and wonderful discoveries of
the age.

The rise and progress of spectrum analysis are known to most
of the Fellows of the Microscopical Society ; it is therefore unneces-
sary for me to trouble you with any preliminary observations con-
nected with either.* I am, however, desirous of directing your
attention to that very interesting field of research immediately con-
nected with the colouring matter of flowers, the composition of
which, and the part played by the action of light in its formation,
is left for spectrum analysis to reveal. It is my purpose on the
present occasion to make some observations upon the results ob-
tained in the preparation of the colouring matters for spectroscopic
examination. I must also request you to receive my paper as one
suggestive of a subject to those whose opportunities and leisure are
greater than my own, trusting it may prove to be a finger-post

* It is simply necessary to remark that this paper wes preceded by a few
introductory observations on spectrum analysis of a general and historical cha-
racter, but which were not intended for publication. I purposely confine myself
to original observations on the colouring matter of flowers, which have more
particularly engaged my attention. With regard to certain remarks, purpwrting
to be a criticism on my paper which appear in the Proceedings of the Society
(June meeting), they are so perfectly irrelevant and discourteous to me, personally,
that I must decline to answer them. .

VOL. II. K

122 Transactions of the OUT Cee ee

pointing the way to an interesting department of physical science,
in which the microscopist equally with the chemist may reap a rich
harvest.

It is a generally received opinion that the chromule of flowers
is due to the chemical action, actinic rays, of light on the juices or
protoplasm of the plant during growth. It is known, however, that
the powerful action of light, in some instances, tends to decolorize
flowers: therefore the gardener screens his choice tulip from the
direct rays of the sun. It is evident that the phenomena associated
with the formative colour process, which lends so much beauty to
the floral world, is only half explained by the light hypothesis.
Besides light, there must be other forces at work which enable the
plant to separate from the soil, or select from within its tissues,
certain constituents, of which we know little, such as those stored
up in the woody material of the stem or root, yet so far removed
from the presence of light that they appear associated with it only
ina small degree. In such situations are found very large quan-
tities of colouring matter, differing in character to that of the
petals; the stem or root, at first green, becomes brown, red, or
black, and ultimately forming dye-woods, which are of so much im-
portance in a commercial point of view.

No doubt light is an indispensable agent in the production of
the cromule of flowers ; and the curious part of the change is that it
should be so diversified in the petals, imparting to them brilliancy
and variety of the most perfect and pleasing character. The modifi-
cations of tints are supposed, in a measure, to be owing to the nature
of the cuticle through which the colour in the interior of the petals
is viewed ; if the colour is more or less yellow it is modified by the
character of the more superficial cells. ‘This, however, offers no ex-
planation of the colouring matter found in the roots, and which
must differ in its nature with the chromogen of the petals. It is
remarkable to notice that although certain plants, as the beetroot,
readily yield up their colour to water, nevertheless during the state
of health and vigour they seldom part with any considerable
portion of it to the soil in which they grow, not even during long-
continued rains. The alkanet, the root of which is the great
storehouse of colour, will not, under any circumstance, part with
it to water. Spirit, oil, and turpentine are its particular solvents.
Will not spectrum analysis enable us to solve some such mysteries
in vegetable physiology, or explain the optical and physical differ-
ences of two bodies growing on the same stem ?

The colours of flowers, botanists tell us, may be arranged in two
series, the zanthic or yellow, and the cyanic or blue, while red is
common to both, and green intermediate. ‘The red colour of
certain leaves is owing, it is thought, to an excess of acid in their
juices. This fact appears to receive support from the circumstance

Monthly Microscopical] = Royal Microscopical Society. 123

that the red leaves of autumn partially recover their green colour
when subjected to the fumes of ammonia. ‘The calorific ray of the
spectrum has probably more to do with the formation of acid than
the actinic ray. I have noticed in the garden rhubarb that when
leaves are more exposed to heat and light they become quite red ;
when tested, the acid reaction of such leaves appears to be increased ;
the solutions obtained from them are of a deeper red colour, and
produce the same absorption of the spectrum as the more decided
red solutions obtained from flowers. Most vegetable blues are
changed to reds on the addition of an acid, thus showing the ap-
parent connection between the relative amount of acid in the com-.
position of the colour. It does appear, then, when colour is taken
alone it affords no conclusive information respecting the chemical
properties on which it depends. The same tint may be made up
in an infinite variety of ways from the constituents of white light.

Starting from green, which may be taken as a state of equili-
brium between blue and yellow, the colour quickly deepens, and
passes through blue and violet to red. This change is due to
oxidation ; while the transition from red to yellow may be regarded
as a deoxidizing, or reversing process. Modifications are produced
by the retention of a larger proportion of carbonic acid, by the
predominance of an acid, an alkaline state, or the presence of nitro-
gen which accelerates the absorption of oxygen ; and when in contact
with ammonia, nitrogen may assist in the production of a blue or
violet colour.

With regard to the formation of colour, this must be consider-
ably modified, or accelerated by the presence of oxygen. Plants
while liberating large quantities of oxygen retain in their juices
much of the same gaseous matter; and it is a well-established fact
that intensity of colour in no small degree depends on the absorp-
tion of oxygen and the quantity plants are able to store up,—in
other words, upon their oxidizing power. ‘The oxidizing process
is greatest during sunlight, when another element also comes into
play and exercises some influence, that received from the sun’s rays
and stored up as heat, and rendered latent, in the form of cellulose
or wood, fixed and volatile oils, &e. Latent heat is undoubtedly
an important accessory in many ways; as in the formation of the
saccharine, starchy, and albuminous principles—the ammonia and
water derived from the soil being necessary ingredients—and in the
colour-making process, especially when colour is to be stored up
in the roots of plants.

In order to observe coloured matters of any kind with any
degree of certainty they must be examined in a pure spectrum, and
to do this effectually the material must be so placed that it ‘shall
intercept a beam of light which forms the spectrum, and when well-
defined reactions of coloured solutions or materials have once been

K 2

124 Transactions of the Myournsl, Sept 1, 1869.

carefully ascertained, with special reference to certain lines in the
spectrum, there will be no difficulty whatever in tracing them
again, even should they be disguised by the presence of other sub-
stances.

So far as I can ascertain respecting the colours of flowers, none
possess the property of perfectly homogeneous simple colours, as all
permit more or less of different colours to pass. If any had a
single colour only, the spectroscope would allow that one to pass,
while absorption of the rest of the spectrum would occur. Various
parts of flowers yield differently-coloured solutions, which give
varying results in the spectrum.

All coloured solutions appear to have a limit set to their
dilution; when this is transgressed no reaction is produced on the
spectrum. This limit may be ascertained by experiment, and test-
ing the effect on the spectrum. For this reason it 1s necessary to
submit various thicknesses or strata of the coloured solutions to the
micro-spectroscope, otherwise points of interest will be missed. For
the examination of vegetable fixed oils the test tube should not be
less than an inch and a quarter in diameter. Density of colour is
in most cases the guide for the determination of this point.

If the prisms are not carefully adjusted or arranged, unequal
dispersion of the spectrum is produced. There is also usually a
difference between the length and intensity of the bands, generally
the blue end is twice as long as that of the red; and although
narrowing the slit in a measure corrects this, it will not do so
to any considerable extent. As every part of the band differs in
refrangibility, the delicate lines produced by some solutions can
only be brought out by accurately focussing that particular part of
the spectrum in which they often too faintly appear.

The rack and pinion motion in the eye-piece must be fairly
brought into use, and the results observed with artificial light
should be corrected by daylight. Bands in the red end of the
spectrum are best brought out by artificial light, while those in the
blue or violet are better observed by daylight. It not infrequently
happens that with some kinds of daylight admitted into the apart-
ment its chemical composition is sensibly affected, the Fraunhofer
line D appears, or even a series of bands which convey delusive
appearances: this must be guarded against.

Provision is made in well-adjusted instruments for the correc-
tion of some of the evils spoken of. It is only proper to say that the
spectroscope I use is the Sorby-Browning direct vision, which has
the necessary appliances for obtaining careful adjustment, and is
in every way the most convenient form of instrument.

Mr. Browning has, with his usual ingenuity, lately constructed a
small and portable form of instrument, which can be carried in the
waistcoat pocket. It is cheap, and can be employed either with or

Secon | sos Royal M: acroscopical Society. 125

without the microscope; the dispersion obtained with this small in-
strument is remarkable. A description of it appears in the August
number of the Journal, page 65. Mr. Crookes exhibited at a late
meeting of the Royal Society a spectroscope adapted to use with the
binocular microscope, which he said had been devised to obviate the
disadvantages of the ordinary micro-spectroscope.

The instrument is described in the June number of the
Journal, page 871. 1 would observe, it appears to me to differ
in no very essential particular from one constructed by Mr. Brown-
ing two or three years ago, and which was soon after abandoned.
I am not at all surprised that it should have been thrown aside, as it
occurred to meat the time that its disadvantages counterbalanced its
advantages. The defects of that of Mr. Crookes are that it requires
the addition of a substage to carry the condenser, slit, and reflect-
ing prism, and also a box to hold the dispersion prisms. The prisms
and slit being attached to different parts of the microscope, the
apparatus is more likely to get out of order than that of the Sorby-
Browning, in which the prisms are fixed in their required and re-
lative position in the eye-piece. The microscope must be sent to
the maker of the spectroscope; certainly a disadvantage, when by
cutting out a piece of cardboard into which an eye-picce fits is all
that is required for the purpose of adapting the “direct vision
Sorby-Browning instrument.” ,

Mr. Crookes refers to the convenience his form of spectroscope
possesses over others, in enabling observers to use it with a bino-
cular microscope; it should, however, be borne in mind that the
light is much degraded by passing through a narrow slit, and is
then spread out by the fan-like action of the prisms, and that
many lines which may exist in the deep-blue of the spectrum
will probably be lost or passed over unrecognized, particularly if
the light be divided between two eye-pieces. Mr. Crookes forgets,
also, that the best results are those obtained with a limited amount
of dispersion. Substances which show several fine absorption bands
with a low dispersive power, appear to be without lines when a
higher dispersive power is employed. A solution of chloride of
cobalt in chloride of calcium will show this most conclusively.
Not the least important part is, that the whole apparatus will be
necessarily much more costly.

An interference spectrum is employed by Mr. Sorby for the
purpose of dividing the spectrum into regular intervals, for the con-
venience of facilitating a careful record of the results obtained.
This, in the form proposed by this gentleman, is not unattended
with disadvantages, when reduced to practice. If considered neces-
sary to employ an artificially divided scale for reference, in place
of the now universally adopted Fraunhofer’s lines, it will surely be
better to make use of a natural material, as Zircon, discovered by

. * nye, - 1
126 Transactions of the Me oe eee

Professor Church, which when cut at the proper angle gives a
series of unvarying and equally divided bands throughout the
spectrum. This mineral substance is even preferable to the nitric
oxide gas of Brewster, which was proposed for the same purpose
some time since by Dr. Thudichum ;—claimed lately by the editor
of the ‘ Quarterly Journal of Microscopical Science’ as quite a new
discovery of his own. The spectrometer devised by Dr. Thudichum
for his laboratory experiments, St. Thomas’s, enables him to obtain
a scale divided into 2000 divisions of the colour spectrum.*

At the present moment nothing has been satisfactorily proposed
for a systematic grouping of the colours; but it seems to me that
a preference should be given to the proposal for making the order
of the bands the basis of our future arrangement. Take the
normal chlorophyll band, when that has been definitely fixed, as
group 1; then a Tauracine band; the permanent three bands (of
red cinararia; the six of Berberis; and those producing general
absorption might form a distinctive group; but it would certainly
be preferable to refer to the absorption bands of chemical salts or
minerals, as these are more constant. After this has been fairly
done, may we not hope so to generalize the facts as to apply the
knowledge obtained to some useful purpose, as that arrived at by
Professor Roscoe in determining the spectrum of the Bessamer
process in making steel ?

In the preparation of the colouring matters of flowers, it is of
less importance to attempt to get rid of any excess of acid that
may exist in their petals, than it is when it is wished to extract the
pure and simple chlorophyll of the leaves of plants, the object
being that of obtaining the colouring matter in its intensest and
purest form. ‘To effect this, steeping the petals in water will, not
serve the purpose, as only very few flowers thus part with more
than a portion of colour. In some instances it appears to produce
what may be described as a decomposition ; depriving flowers of their
chromule, and leaving behind only a colourless solution. Spirits
of wine is certainly the most efficient and widely useful menstruum
for the purpose of extracting chromule and retaining it unchanged
for any length of time. I have found methylic, or wood spirits, bisul-
phide of carbon, chloroform, glycerine and spirit, all useful agents ;
but although spirits and water are the chief solvents of vegetable
colours, it frequently happens that they are not equally efficient :
there is consequently a good deal of variation in the spectrum
results.

In the preparation of coloured solutions, I find it better not to
crush the petals or leaves previous to immersion in the spirit or
water. Crushing often changes the colour, and, as a rule, it is

* “The Chemical Identification of Disease,’ by Dr. Thudichum. ‘Tenth
Report Public Health, p. 192. 1868.

Mourlal, Seve es | © Loyal Microscopical Society. 127

quite as readily extracted without resorting to this process; another
advantage is gaimed, inasmuch as clear transparent fluids are ob-
tained without incurring loss by filtering through blotting-paper.
Occasionally it is seen that spirits affect results, by the extraction
of the gum resin and essential oil of the flower along with the
colour; but this is not a very grave evil, nor does it appear to be
necessary to strain away the pollen grains, which are at times sus-
pended in considerable quantities; indeed, this will be found to
be an excellent way of collecting and preserving the pollens for
microscopical examination. A little pure simple syrup should be
added to the solutions before the tubes are filled and hermetically

- gealed.

The pure vegetable and animal oils, which in themselves
produce no reaction on the spectrum, may in some instances be
employed with advantage for the extraction and preparation of
colouring matters. The fine colour of Anchusa tinctoria (Alkanet-
root) is readily extracted by any kind of oil; in this menstruum it
becomes a fixed colour, and a much finer series of spectrum bands
are obtained. An oil that m no way affects the spectrum, as ex-
pressed castor-oil, or purified cod-liver oil, should be employed
for the purpose of dissolving out the colour of alkanet-root. A
good almond-oil coloured pink by alkanet-root gives a fourth and
fifth band in the blue and violet. It is curious to watch the re-
actions produced in the spectrum by the combination of various
fixed oils with this colouring matter; with ordinary flask olive-oil,
the chlorophyll band of the oil itself seen in the red is exaggerated,
as well as the second band in the blue, and the violet is wholly
absorbed ; castor-oil gives an extra band in the indigo; cod-liver
oil augments the blue end of the spectrum, and develops a third
band in the blue. The vaunted Macassar-oil, supposed to be
prepared from roses, evidently owes its colour to alkanet-root, as it
produces the same series of bands as are produced by alkanet-root
in olive-oil. When to a small quantity of spirituous solution of
alkanet-root lime-water is added, it changes to purple-pink, or
red ; the absorption bands are well marked, especially those between
Cand D, and D and E; but the lines do not appear exactly in the
same portion of the spectrum indicated by Mr. Sorby in his ex-
periment with carbonate of soda. This solution, like his however,
is not permanent, and with the change of colour the absorption
bands disappear. If to a pink-coloured spirituous solution simple
syrup is added, the red end of the spectrum is greatly augmented ;
the two bands in the green are sharply defined, and that in the
blue is wider, while the violet is completely absorbed. Although
the sugar crystallizes out and falls to the bottom, the colour does
not fade. A solution of a bright pink appears to be the best tint
for observing the reactions of the anchusa-root, and the employ-

128 Transactions of the Besta
ment of transmitted or reflected light produces a marked change in
the spectrum of this substance, as well as in that of many others.

A very large number of the petals of flowers yield solutions
closely resembling the dilute solutions of alkanet in spirit, so that
in the ordinary way it is difficult to determine the difference between
them. ‘The spectrum of alkanet-root at once removes a doubt ; but
so much cannot be said for a number of other red or crimson solu-
tions. The brilliant damask rose, when immersed in water, loses
all its colour; which is at once restored on adding a drop of sul-
phuric acid. A fine pink is obtained, which is permanent, by
diluting with glycerine and spirit. This heightens the red end of
the spectrum, producing a brilliant halo of red light; the rest
of the spectrum is absorbed; or, if a paler solution is used for
examination, a broad absorption band occupies the green, and the
blue of the spectrum is deepened. The crimson purple-coloured
petals of fuschia lose colour by immersion in water or spirit and
water, but a drop of acid at once restores the brilliant colour of the
flower, and the solutions produce the same reaction on the spectrum
as the red rose. From another variety of the fuschia, bearing white
and red coloured flowers, a paler solution is obtained, which a drop
of acid converts into a pink; but if an alkali be added the colour
changes to « yellow, and no reaction is observed in the spectrum.
Nasturtium petals produce a fine amber red, which changes into a
crimson on the addition of an acid ; and its reaction on the spectrum
is the same as that of the damask rose. Cactus speciosa petals yield
a fine crimson-coloured solution. Acid only very slightly deepens
the solution, which augments the red; and a broad dark band
occupies the yellow and green, while the blue becomes more
intense. From the juicy leaf or stem of the Opuntia cochinil-
lifera, upon which the cochineal insects feed, chlorophyll cannot be
obtained in sufficient quantity to produce any reaction on the
spectrum. A fine crimson colour is, however, extracted on digest-
ing the Coccus cacti (cochineal insect) in distilled water, which
produces a general absorption of the green, blue, and violet; but
upon adding a small quantity of ammonia to the solution, the
colour is changed to a lake or reddish purple, when two sharp
bands appear in the yellow and green, and one in the blue; the
violet is intensified. When liquor calcis is added to another
portion of the solution it nearly approaches a violet, and produces
a similar series of bands; on adding an excess of alum, the colour
changes to a yellow, which absorbs the greater part of the green
and. blue.

The deep crimson colour obtained from the Peony produces
general absorption below the red; when a small quantity of liquor
potassze is added to the solution, this red colour is converted into a
green, and characteristic bands appear in the yellow and green
part of the spectrum; if the solution be pale enough, another line is

mournal sept ts | Loyal Microscopical Society. 129

seen in the blue. The tint of this solution is not permanent ;
decomposition takes place, and the bands disappear. The red
poppy is very similar in its reactions. The ranunculus gives a
band in the red and orange, and deepens the rest of the spectrum.
The solutions of the crimson petals of the geranium behave in a
precisely similar way. ‘The Iris imparts a fine reddish-purple
colour to alcohol and water, the solution of which gives a band in
the red, orange, and green, and partially absorbs the blue end of
spectrum ; the addition of citric or mineral acid deepens the colour
of the solution, and destroys the several bands, producing a general
absorption of one end of the spectrum ; alkalies do not restore
the bands in the spectrum.

Litmus, a well-known colouring matter, prepared from Rocella
tenctorva (canary archill or orchill), and which yields a valuable
dye, and is employed largely for dyemg broadcloth, to which it com-
municates a peculiar purple lustre when viewed in a certain light,
is soluble in water and alcohol, to which it imparts a beautiful
violet colour. This solution produces a fine band in the red, and
another broad one which completely absorbs the orange and yellow
and a portion of the green, while it deepens the violet end of the
spectrum. Acids redden the solution and change the position of
the spectrum ; the red is rendered more intense, the orange and
yellow are restored, and a broad band appears in the green and
blue. Carbonate of soda restores the violet colour of the solution ;
at the same time the band in the red reappears, a separation of the
green band takes place, and a faint one is produced in the blue.

Tradescantia virginica (Spiderwort), the jointed hairs of which
show the circulation of the chlorophyll, so interesting to micro-
scopists, yields to alcohol and water a reddish-purple solution, of
the same colour as the flowers, the spectrum of which somewhat
resembles that of Lobelia speciosa, but is more decided and curious.
The red is intensified ; sharply-defined bands appear in the yellow
and green, and I believe in the blue; but owing to the exaltation
of this end of the spectrum it is not quite easy to say. Larkspur
yields a pale reddish-blue solution, and produces four absorption
bands in the red, green, and blue ; there is no action on the yellow,
although the colour has a good deal of blue in its composition.
Vegetable blues are not invariably acted upon by acid or alkalies.
It does not follow that acid converts them into red, and alkalies
into green. In Mr. Sorby’s experience of the solution of Cesalpina
erista (Brazil wood), called yellow, but which when first acted
upon by water forms a red solution, and turns yellow after stand-
ing some time, probably owing to a deoxidation of the solution,
he observed that the yellow solution became pink on the addition
of an alkali; Brazil wood, however, is used as a red dye, while
from other varieties of the Caesalpina black dyes are made, and
even fine black ink. The yellow solution of this substance forms

130 Transactions of the ere a

rather an exception to the rule, as rarely in my experiments did
yellow solutions appear to be materially acted upon by alkalies.
Yellow rose-petals form a deep amber or orange coloured solution,
which is brought nearer the yellow by carbonate of soda. The
addition of either a vegetable or mineral acid produces little or no
change in the colour of the solution, nor do they cause any absorp-
tion of the spectrum ; caustic potash and liquor calcis deepen the
colour, changing the solution to a greenish-yellow, but no corre-
sponding change takes place in the spectrum. The Brazil wood
soluticns produce the absorption reactions of the reds; that is, both
with its pink and red solutions there is an exaltation of the red; a
broad band in the green, which some tints seem to divide into two;
another in the blue, with a deepening of the blue and violet.

The yellow tulip solution is quite as much unaffected by re-
agents as that of the rose. From the tulip-petals a yellow crys-
talline matter is obtained, which no doubt is identical in its character
with Dr. Thudichum’s Luteine, which he says “shows three absorp-
tion bands in the blue violet and indigo portion of the spectrum,
and are indicative of the presence of this body in yellow solutions.”

I have observed that in a very great many instances solutions
obtained from either flowers, leaves, or stems of plants, produce
uniform results on the spectrum. ‘T’he evergreen berberries with
their pretty leaves, some of which are a reddish-green or deep
purple, and produce an abundance of orange-red flowers, all yield
solutions to both water and spirit, which give a most interesting
set of absorption bands, at least six in number; the solutions keep
well, and the spectrum is very permanent. The highly-extolled
Peruvian Coca, the leaves of which are said to sustain the life of
the aboriginal races for a long time, chiefly derive their nutritive
powers from the large quantity of saccharine matter contained in
them; from its flower or leaf a fine bright-green is extracted by
either water or spirit, producing a sharply-defined set of absorption
bands nearly resembling the berberry. I find that numerous dif-
ferent solutions yield an almost identical series of absorption bands,
as the pine-apple, digitalis, hyoscyamus, senna, belladonna, lau-
restinus, buckthorn, &. With Professor Stokes, I believe that
spectroscopic examination of the constituents of plants and animals
will certainly aid in their identification, “the force of the addi-
tional evidence being greater or less, according as their optical
characters are more or less marked ; or it will establish a difference
between substances which might otherwise erroneously have been
supposed to be identical.”

The blue series of colours in flowers are exceedingly difficult to
extract, they resist almost every solvent of other colours. I believe
they have rarely been obtained in a pure form; but if a small
quantity of red enter into their composition, then the colour is

Monthly, Microseoicl| — Royal Microscopical Society. 131

extracted without much difficulty. Nearly all blue flowers yield
yellowish or pinkish-yellow solutions. Alkalies deepen these
colours and bring them nearer to green. Acids on the other hand
mostly convert them into reds, they then produce the same effect
on the spectrum as reds. ‘The extraction of colour from the
leaves of plants of a deep red, as Coleus, &¢., appears to take
place by deoxidation ; on immersing such leaves in alcohol the red
colour is quickly extracted, and the leaves become quite green;
after standing by twenty-four hours the green becomes paler, and
ultimately on decanting the solution the leaves are left colourless.
Upon removing and drying them in the air a considerable portion
of colour returns. ‘The solution first obtained produces a more
decided reaction on the spectrum than subsequent solutions, although
the latter apparently contain a larger quantity of chlorophyll.

Most red solutions produce, as I have said, a general absorption
of the spectrum below the red, but if properly diluted to a pink,
they give two or more bands in the yellow and green, deepening
the blue end. Ifa small quantity of blue enters into the composi-
tion of such solutions, bands will also be noticed in the blue, or the
violet, and this portion of the spectrum will be seen to be more
intense; good illumination and dispersion, as well as proper
dilution, being indispensable to bring out the bands in the violet.
The red end of the spectrum is at the same time often more
brilliant.

A solution of Brazil wood, to which an alkali and alum had been
added, remained of a yellow colour ; but on dilution it became pink,
and on standing in a strong light it changed to a deep red. This
solution produced absorption of the whole of the green portion of
the spectrum ; but upon again diluting it down to a pink, a broad
well-defined band appeared in the green and yellow, deepening the
blue end.

Methylic alcohol requires caution in using. It is very liable
to produce decomposition of the colour obtained, from the circum-
stance that the commercial spirit sold under the name of “ Methy-
lated spirits,” is often contaminated by impurities. The fine scarlet
cactus flower readily parted with its colour to methylic spirits, but
it is soon changed to a yellow, and finally became colourless.

Memorandum of Spectroscopic Researches on the Chlorophyll of
various Plants. By the late Witt1am Brrp Herapats, M.D.,
F.R.S., F.R.MS., &e.

THE late lamented Dr. Herapath was actively engaged during the
summer of last year in the study, by means of the spectroscope, of
the optical characters of chlorophyll. At the time of his death he

© Monthly Microscopical
132 Transactions, &e. Seurnel, Sept, 1, 1369.

had unfortunately written no paper on the subject, though he had
had a diagram, exhibiting his leading results, lithographed and
coloured, to accompany a reprint of the intended memoir after pub-
lication. This chart, with the following extract from a letter to
his friend, J. E. Howard, Esq., of Tottenham, will suffice to rescue
from loss Dr. Herapath’s last scientific work.

Extract from Letter.
“ June 27th, 1868.

. “TJ have found results of very considerable interest in the last de,

consignment you sent me. There are three solutions of the chlorophyll
of the Cinchona Succirubra. One in alcohol is scarcely coloured, having
in fact a tinge of olive-green. This in the spectroscope was perfectly
marvellous to me. It gave four well-marked absorption-bands, one
deep sharp line in the red; another, rather narrower, in the orange,
coincident with D, or the sodium-line; one in the green, about 5,
coincident with the Thallium green band; and a fourth on the blue
line F, nearly as broad as that in the red. The ethereal solution
gave ditierent results. It showed only three bands of absorption,
nearly the same as in the last case (though all of them fainter) ; but
the fourth in the blue was not apparent, the whole of that end of the
spectrum being absorbed a little beyond the green band b. This
solution was deep emerald-green, and even on dilution did not alter
its phenomena. The acid alcoholic solution was as deeply green as
the last, but gave only the sharp broad absorption-band in the red,
and two very faint ghostly bands in the position described above of

the D and b lines respectively. |

*‘ Extensive additional researches on the chlorophyll of various
plants have given some very extraordinary results, which I am now
working out. The chlorophyll was dissolved out by Spiritus Vini
Rect., digested for some hours in the cold; some plants being fresh,
and others dried.

“Five classes of phenomena exhibit themselves, but all agree in
having the red absorption-band broad, sharp, and well-defined. Some
have this one band only: the Lilac is of this type.

“There are two classes in which two absorption-bands occur. One
has the red and the orange bands, of which the Fuschia, Guelder-rose,
and Tansy are examples; another, in which the red and the green
bands are alone coexistent. Ivy is the type of this class, and it is
immaterial whether we take last year’s leaves or those of the early
spring; the results are the same.

“The fourth class consists of the two former spectra superposed.
Three lines occur, the red, the orange, and the green bands, at C, D,
and b, as before. This is by far the largest class, and I have thirty or
forty examples of it. C4nothera biennis, Laurestinus, &c., are types,
with the ethereal solution of the leaves of Red Bark.

“The fifth class consists of those having properties similar to the
alcoholic solution of Red Bark before described. I have only found
eight of these as yet, and not all equal in power, namely :—Berberry

The Monthly Microscopical Journal Sept 11869.

ic Cubittdel “Tiffen West sc :

Structure of Floscularia coronetua:.

*Tournal, Sept. 1, 1869. Floscularia coronetta. 133

(fresh); Sloe (fresh); Tea (dry); Hyoscyamus (dry); Senna (dry) ;
Digitalis (dry); and Red Bark (alcoholic).

“JT think you will agree with me that these are very important,
interesting, and novel experiments, and well worthy of being followed
up. I can arrive at no solution of these facts as yet, and cannot see
why solutions which have such equally green tints to the eye, should
present such diverse optical effects. There must be some cause, and
the most probable is the existence of different substances in these
leaves.

“W. Birp Herapats.”

The foregoing conveys, however, but a very inadequate idea of
the labour which Dr. Herapath had devoted to the subject. He
had, it appears, analyzed optically upwards of 250 solutions; and
in his rough MSS. he enumerates no less than fifty-four plants in
the Fourth (or three-barred) Group. This list is appended, as it
may be of service to future investigators ; but it is obvious that we
have now no means of knowing whether each individual of the
series had been as fully worked out and verified as those given in
the lithographed chart.

Laurestinus, Cucumber, Bay, Aconite, Ginothera biennis, Willow, St.
John’s Wort, Red Rose, Everlasting Oak, Scrophularia nodosa, Oak,
Foreign Oak, Edible Chestnut, Horse-chestnut, Red Horse-chestnut, Larch,
Maple, Alder, Lime, Birch, Walnut (leaves), Ficus, Buckthorn, Nut,
Holly, Red Bark leaves (ethereal), Red May, Wild Service Tree,
Laurel, Cherry-laurel, Virginian Creeper, Wild Raspberry, Radish,
Horseradish, Rhubarb, Dock, Secale, Beet-root, Blackberry (old), Iris,
Red Lily, Lily of the Valley, Fern, Senecio Jacobea, Gallium album,
Purple Sow-thistle, Periwinkle, Willow Herb, Cicuta virosa, Malva Mos-
chata, Lamium Purpureum, Solanum Dulcamara, Wild Sage, Stork’s-bill.

IIl.—Floseularia coronetta, a new Species; with Observations on
some Points in the Economy of the Genus.

By Cuarzes Custirt, Assoc. Inst. C.E., F.R.MLS.
Puates XXIV. anp XXYV.

My attention has long been directed towards an investigation of the
mechanical actions of the vibratile cilia in the Rotifera, having
failed on all occasions to recognize in what I observed, the effects
that should properly result from the actions described by others.
For instance, in Melicerta, Mr. Gosse writes* that ‘“‘ The ciliary
vortices produced by the waves of the coronal disc pass together
through the upper sinus, and are hurled in one stream along the

* ¢ Phil. Trans.,’ 1856.

134 Floscularia coronetta. ee ee ae

centre of the face, nearly to the projecting chin.” And again,*
*« The particles are hurled round the margin of the disc until they
pass off in front through the great sinus between the larger petals.
...» We see them swiftly glide along the facial surface, following
the irregularities of outline with beautiful precision ;” while my ob-
servations, on the contrary, show that the marginal cilia do not
hurl the particles round the margin of the disc, but that they
apparently make a continuous procession in one and the same
direction around all the four petals; and the few particles that do
follow the irregularities of the outline approach the sinus from
opposite directions, on the one side of the animal in the same, and
on the other side in the opposite direction to the procession of the
marginal cilia, which could not happen if their passage were due to
the direct action of such cilia; in fact, every particle that passes
through the sinus is, during that passage, wholly unappropriated
by the animal.

The true actions and functions of these and the accessory cilia
about the trochal disc in effecting the prehension, selection, and ap-
propriation of the particles respectively required for alimentary and
architectural purposes is very distinct, and I hope at no distant
period to arrange the deductions from these observations in a pre-
sentable form. With this end in view I have been led to a con-
sideration of somewhat similar points of unconformity in the genera
Stephanoceros and Floscularia, these animals having been in some
cases referred to as occupying the anomalous position of Rotifers
without rotary organs, though entitled to the position they occupy
in the class by virtue of their inheritance of the same type of man-
ducatory apparatus. Then again, the ciliated coronal disc, with its
radiating sete, has been frequently accepted and erroneously styled
the rotary organ, in the face of visual evidence to the contrary ;
the seta produce no continuous current, and beyond the sense of
feeling and the function of retaining the captured prey within the
funnel, they appear to possess only a capacity for twitching and
jerking the involved particles from point to point, yet notwithstand-
ing, it is evident there frequently exists a distinct and persistent
vortex in their funnels, entirely independent of the action of the sete,
the necessary result of some motive power in the funnel, the true
rotary organ in fact, which they certainly all possess ; and in animals
of the lowest form in their class, with the manducatory apparatus in
a state of deep degradation, we must expect to find subordinate
organs at a proportionately low point, and of the existence of such
a low type of rotary organ I was able, by dint of careful observation,
with superior appliances, to satisfy myself both as to the form and
position in Stephanoceros, and subsequently much gratified to

* «Pop. Sci. Rev.,’ 1862.

ae Floscularia coronetta. 135

find that a corresponding organ had previously been observed by
Dr. Dobie, further described and illustrated by Dr. C. T. Hudson,
in F’. campanulata, in a paper communicated to the Bristol Micro-
scopical Society in 1867, and to the courtesy of the honorary secre-
tary of that society I am indebted for a copy of their Proceedings
containing the same. ‘Then, in the month of June last, when in
quest of members of the family Flosculariade, a small gathering
of the prolific water-moss Pontinalis antipyretica, from one of the
small pools on Wimbledon Common, afforded me, amongst other
species, a few specimens of the elegant Ploscularza that forms the
subject proper of this communication, and in describing this I trust
I may, by frequent reference to the sketch and diagrams, be able to
convey a lucid explanation of the character of the rotary organ
which is very distinctly exhibited in this species.

In venturing to claim for it a place as a distinct species accord-
ing to the present classification, I have been assisted in my selection
of a title by a review of the examples afforded in the hitherto known
species, in all of which the titles have been determined from the
peculiar formation of the coronal disc, and on comparing this with
the discs of the other species (Plate XXV., Figs. 2, 3, 4, and 6) I
confidently rely on the conviction that the claim will be undisputed ;
and from the fact of having subsequently found, and continue still
to find it inhabiting the water ranunculus on Wandsworth
Common, widely separated from the first locality, there can be no
question as to the species being permanent.

The first specimen that presented itself I mistook for the
moment, on account of its size, its wrinkled footstalk, and its slender
protruding lobes, for a young Stephanoceros, and on better ac-
quaintance it certainly departs somewhat from the characters of the
genus Floscularta, which are, as given by Oken,—Frontal lobes
short, broad, knobbed, expanded ; ciliary setae very long, radiating
crowded about the knobs; jaws each of two teeth. But inasmuch
as the lobes in comparison with their width (the only gauge of
length) are long, slender, and erect, it follows so far the characters
of Stephanoceros, with which also there are further points of resem-
blance—first, in the fact that the gelatinous case is of the same
viscid character, and not a hollow tube with thin walls, as described
for Floscularia. It is not improbable however, or even unrea-
sonable to suppose, in the face of accidental incidents that have
offered themselves in support of that statement, that the tubes of all
the species may also be of this same viscid composition. The fol-
lowing point can only be considered as a superficial resemblance,
but at a first glance is most striking,—the dorsal lobe exhibits no
palpable modification in outline, as is so noticeably distinguished in
the other Floscules by the increased height and basal expansion
both in F’. ornata and I. campanulata, and by the addition thereto

py, a Monthly Microscopical
136 Floscularia coronetta. ee ee

of the specific horn in F. cornuta (Plate XXV., Figs. 2, 3, 4,
and 5). There is, however, a physiological distinction with the
dorsal lobe of this species which will be described in a subsequent
paragraph.

An individual of this species when fully extended measures 3';th
of an inch from the foot attachment to the knobs on the frontal lobes,
beyond which the setz can be definitely measured to a distance of
goth of an inch, and at such times far excels in grace and elegance
of figure any one of the others, the body curving easily up from the
footstalk terminating frontally in a miniature coronet, and hence
its specific title; but its refined symmetry is frequently diminished
by being contracted to the extent of one-fourth of its length, with
its body more swollen and rounded, and its footstalk drawn into
numerous transverse wrinkles, characteristic of the family. ‘These
periods I notice are times of repletion.

Generally, the gelatinous case is scarcely to be detected, except
from the accumulation of filamentous alge and particles of floccose -
matter that are gathered and attached round about the posterior
regions, giving it a much broader and shorter appearance than is ever
seen in the tubes of other species, this extraneous matter reaching
only a little beyond the footstalk of the expanded animal, which
when withdrawn within this shelter is extremely difficult to find,
from the general resemblance of the body and stalk to the surround-
ing aggregation of particles and filaments: unlike F’. campanulata,
it is extremely sensitive to external interruption, remaining long in
retreat before venturing on its cautious and deliberate eversion ;
and to these particulars, added to that of its scarcity—occurring
only once among a hundred others—may be attributed the fact of
its having hitherto escaped observation.

The hyaline tube however, 2s present, projecting well up into
the neck, far above the nest-like vegetable aggregation, studded
throughout its mass with granules, which, by their passive repose
in the midst of myriads of restless monads and oscillatoriz, give
the first and almost only intimation of the presence of their viscous
matrix, except at certain periods after acts of evacuation, when it
is seen to be more profusely pervaded with granules of the ejecta-
menta, particularly along the body of the inhabitant, which in
retracting leaves most distinctly revealed the internal walls of the
tube, conforming exactly to its outline, and rendered the more
distinct by reason of a greater preponderance at this part of the
voided infusorial particles in varying stages of disintegration, which
clearly proves that the tube isin this species at all events of a viscid
character, the same as that of Stephanoceros.

I will not presume to offer a description of the respiratory,
nutritive, muscular, and reproductive systems which are physiologi-
cally common to the genus, and are so admirably described by Mr.

Mfournal, Sept. 1 1309. Floscularia coronetta. 137

Gosse in his facile and forcible manner, further than to note some
points that may differ therefrom in this species, or to suggest further
Inquiries in the economy of them all.

The currents of granular matter circulating between the body
and the disc are here distinctly seen during the act of eversion
issuing in an irregular mass from the second or labial diaphragm,
principally along the dorsal aspect of the body, permeating the
vessel round the neck, and coursing along the channels to the lobes,
which they seem to inspire with sensitiveness; these channels from
the collar to the funnel rim are arranged in pairs running down one
from each angle at the bases of the lobes, except at the dorsal lobe,
along which their course is in one central passage direct from the
collar, the channels in pairs anastomosing at the diaphragm, de-
scending thence to the posterior swelling of the body, where they
are distinctly seen to merge into one tube, passing down to the foot,
along the whole course of which are sparingly distributed isolated
molecules of the circulating matter.

The frontal lobes are found somewhat of a dumb-bell figure, in
transverse section (Plate XXV., Fig. 9), the thickened margins being
continuous productions of the funnel rim, at their junction with
which they exhibit internally the peculiarity called “ Vacuola
thickenings” (Plate XXV., Figs. 5, 6, 7, and 9), which, strictly
speaking, is a misnomer, however convenient may be the acceptation
of the term as expressing a “space filled with matter other than
tissue,” because a vacuum implies “a space unoccupied by matter a
they occur in the disc of this species as they do in many other
Rotifers, and also in the prolongation of the body below the visceral
cavity, points which are both effected by the animal’s retraction in
the folding of the disc and the contraction of the parietes of the
body ; and it is suggested for the consideration of observers that
these “vacuola thickenings” are the effects of such foldings and
contractions of the substance of the body in the respective positions
in which they are seen. Take for instance the disc of Lacunularia,
the vacuola thickenings are there shown in connection with radiating
branches, and if a paper disc be made of a similar form, and drawn
through a ring representing the neck, the puckerings or corruga-
tions will assume something of the arrangement of the figure there
shown.

The setz are set, not only on the knobs from which they radiate
in all directions, but are continued on each side of the lobe where
they are very short, along the whole circumference of the disc,
as in FF’. campanulata, increasing considerably in length in the
spaces between the lobes, though not easily seen in a lateral view
of the animal, and in the dorsal lobe the thickened rim is produced
at its base into a rounded process at both angles (Plate XXV.,

Fig. 9 6), from each of which radiates a tuft of sete: approaching
VOL. IL L

138 Floscularia coronetta. MOO ee
in length those on the anterior knobs. ‘This, therefore, is the
distinctive modification of the dorsal lobe in this species ; and when
these distinctions are so persistent in every animal of this genus, it
suggests the probability of an analogous distinction in the isolated
species of the genus Stephanoceros. I have not hitherto been able to
detect the slightest departure externally from the form of the other
lobes, but, though not in support of the assumption, have been made
aware of a perfect band of very small sete running continuously
round the interior of the funnel at the bases of the lobes, exercising
the spasmodic action that distinguishes setee from vibratile cilia.

The rotary organ of F’. coronetta, as exemplifying the type of
the genus, is situated internally at the cervical constriction of the
body or neck, which is furnished with a collar extending horizontally
round its entire circumference, divided diametrically in a lateral
direction by a rounded process on each side (Plate XXY., Figs.
5, 6, 7c); these processes are set with active vibratile cilia, spring-
ing from which and extending ventrally at a great angle of depres-
sion is a minutely ciliated belt (d) attached to the contractile
membrane, in which it here creates a considerable vertical constric-
tion (Fig. 6); and from the ciliated knobs (¢) the dorsal division of
the collar (e) anastomoses with the vascular vessel that descends
from the dorsal lobe, where it forms a similar rounded process (f),
which with the collar is unciliated, but is permeated with the
granular substance that circulates through the disc, and certainly
contributes important service in the acts of swallowing and ejecting.

The depression of the rotary organ is manifest in every species,
for a lateral view exhibits, without exception, the labial diaphragm
correspondingly depressed in the same direction.

The celiated processes are capable, at the will of the animal, of
either vibrating intermittently, producing a similar jerking effect
to that of the sete, or of working in regular sequence and creating
a vortex, in which the particles are seen to revolve upwards through
the rotary belt, and down along the dorsal lobe as shown by the
arrows (Fig.6). ‘The animals appear to possess through the agency
of the simple process the same faculty of discrimination in the
selection of food that obtains in some, if not all, of the tube-building
Rotifera, eminently so in Melicerta: thus the dorsal unezliated
process is seen to approach, and, with the others, simultaneously to
close upon the prey by means of a sudden contraction of the neck
(Fig. 10), to retain the particle for an instant, and then either to
reject or to swallow it, as the scrutiny may decide. In Ff. cam-
panulata this action is very frequent; the dorsal lobe is there
vertically bulged or corrugated inwards down to the semple process
which exhibits the most delicate sensibility, reaching forward as if
aoane on a pivot at the funnel rim at the approach of the minutest
monad.

Monthly Microscopical

Raa Sece | seo, Floscularia coronetta. 139

It is assumed therefore that in these lower forms this member
is the representative of the two ciliated organs in Melicerta, which
manifest such rapid discrimination in its selection either of food or
of building material.

In the act of swallowing, the mouth (9) is protruded upwards
in close contact with these three processes (ig. 10) to receive the
particle and to pass it through the cesophagus (m) on to the man-
ducatory apparatus; the particle is distinctly seen distending the
cesophagus on its passage (Fig. 6/), clearly proving that this can-
not be a simple “waving veil,” as described by Mr. Gosse; but
from the fact of the mouth being a bulging, elongated orifice,
merging into a tube beneath, the upper portion certainly presents
something the appearance of a veil, and the tube necessarily assumes
a waving motion with the muscular contractions of the labial dia-
phragm in its normal position, in consequence of the tube being
longer than would be required if that position were permanent ;
but the cesophagus has to accommodate itself to the arbitrary posi-
tions that the diaphragm assumes, both in the acts of swallowing
and ejecting particles, when the mouth, as before shown, is elevated,
carrying with it and utilizing, so to speak, the “slack” of the tube
that previously waved to and fro, but which is now rendered almost,
if not perfectly straight.

The manducatory apparatus (it does not merit the term mastax)
is situated very low in the stomach cavity, and is extremely small,
the mallei only measuring each spyp of an inch in length; the
stomach appears to be divided into more than one chamber, but
the opacity of the viscera has hitherto prevented my determining
definitely further than an intestine with a ciliated rectum leading
to the cloaca, beneath which, and enclosed in the posterior swelling,
is seen a clear transparent space (possibly a vacuole), but from its
inconstancy it may be assumed to perform the actions of diastole
and systole, the functions of a bladder, and its position near the
cloaca, together with its occupation of a permanent swelling, would
seem to corroborate the assumption.

The rapid process of retraction is very curious, and would be
impossible to determine, except that the cautious and deliberate
manner in which eversion is performed enables the observer to
trace the modus operandi. The frontal lobes are simultaneously
folded inwards and downwards at their bases, and abruptly returned
at a short distance beyond, so that their anterior portions are
retained in an erect position in the centre of the disc, which are
then withdrawn with the funnel, leaving a coma of sete pro-
truding.

The ova, of which I have never seen more than two attached at
one time, measure 33yth by sdoth of an inch in their respective
elliptical diameters, the eye-spots in them very distinct, but less so,

! L 2

140 Observations on Mucor Mucedo, — [Monthly Mictoscoptcal

though apparent, in the young animals 7>th of an inch long, with
their dises developed: in the adult I have not, in this species, been
able to resolve the eye; and this constant occurrence of the eye-
spot, so distinct in the young and ova, and so difficult to resolve in
the adult, when they have been seen in the lower forms, while they
are always visible in the higher, suggests the solution that is here
offered with much diffidence, and must be received as conjecture,
requiring confirmation.

It is opposed to the plan of nature that any organized body
should in any degree degenerate* from the infant to the adult stage;
if, therefore, the eye-spots are present in the young Rotifers, and
apparently absent, or, at all events, difficult to resolve in the adult,
the reasonable inference is, that the eye has developed and not
degraded,—developed as a simple eye of a low type in the form
of a lens, which, as a high refracting body, requires, of course,
careful manipulation to determine with any class of illumination.
In the lower forms it has been found that while any particle of
colouring matter remains no appearance of a lens is visible.

Then, with regard to the higher forms, though the colouring
matter is always present, it 1s changed perceptibly in character in
the adult stage, leading to the conclusion that these possess a low
form of compound eye; that the vanishing colouring matter of the
simple eye is of a different character and composition to the perma-
nent pigment of the compound ; and that in both cases the animals
are blind in infancy.

While, therefore, some of us are spending much time in resoly-
ing and discussing the markings on Diatomacez and Podura scales,
I would invite the attention of observers to turn their attention to
the investigation of some of these doubtful points in the economy
of the higher Infusoria, a field of inquiry inexhaustible in interest.

III.— Observations on Mucor Mucedo.
By R. L. Mappox, M.D,

Tue following remarks on Mucor Mucedo, occurring in a bruised
ripe cherry, may at least add tothe interest which imvests these
humble and prevalent structures, even if they do not exactly con-
firm the observations of others.

Among the Physomycetous Order of Fungi, we find Anten-
nariet and Mucorini, the latter described in the Micrographic Dic-
tionary as having a “Mycelium filamentous, vague, giving off
erect simple or branched filaments terminating in vesicular cells

* We must object to this sweepiug proposition, which is clearly the result of
imperfect acquaintance with the facts of metamorphosis.—Ep. M. M. J.

The Monthly Mace oscopical Journal Sept.1.1869.

i SS

—

che
y whe,

Jig

RL.Maddox del

‘Tuffen West sc.

Mueor JOOOUE ed @iZ

WWest imp.

Moe Geet ee Observations on Mucor Mucedo. 141
(peridioles) filled with minute spores, often with a central column
in the interior.” ‘There are several described species of the genus
Mucorini which is common on decaying fruits, &c., but it is doubtful
whether some of these may not be the same plant under varying
conditions of nutrition and light. In the above perfect plant, as it
usually first attracts the observer, a number of little globular heads
seated on erect non-septate filaments, varying in colour from whitish
grey to grey or brown black, are seen springing from a filamentous
network fixed by short rootlets in or on the substance on which
the plant is seated, the colour of the filaments varying from pale
yellowish to brown.

If with a fine pair of forceps we seize one of the erect filaments
at the base, and place it on a glass slide, we shall probably find we
have removed an entire plant of two to five or more stalks springing
from the same base, terminating above in globose or oval heads,
and below in several branched rootlets.

The globular heads very likely are of different growths, and if
so, applying a little water to the edge of the cover, or some fluid,
we may see (as at a), supported on a stalk, a slight enlargement in
the young peridiole with a central portion or column occupying
all or much of the interior, filled with a finely granular matter or

EXPLANATION OF PLATE XXVI.

. Commencing peridiole.

. More advanced.

. Still more advanced, containing hyaline cells.

. A nearly ripe head, showing the spores set free by water, hyaline cells in
the columella, and polygonal cells in the stalk; a little above the neck
the attachment of the outer membrane, and at the top its hexagonal
structure.

. Large, somewhat denser cells than the spores, found on some of the ripe
heads with ordinary spores.

. Minute bacteroid bodies, and a few free spores.

. Unripe spores.

. Empty ripe spore cases, or capsules.

Oblong spores found near the neck.

. Torula-like spores.

- Minute bodies of f, growing, some very naviculoid in form, others fila-
mentous, others round, free or attached. :

Ordinary spores germinating, capsules burst but adherent.

. Ill-conditicned spore.

. Healthy young mycelium.

. Ordinary ripe spores with corrugations x 750 diam.

. A dense spore, with daughter-cells within of a brown colour, and numerous
pacts globules with dark outline both within and on its surface x 750

iam.

q. A cell with numerous nuclei? = to g.

r. Bacteroid or schizonematoid bodies from the same stock as f.

s

t

a Qoace

aS: SEQ SH

SSS 3 ™

. Same ask x 750 diam.

. Outer spinous membrane of peridiole.

u. Young head discharging its grumous plasma from the contact of water
x 120 diam. ; all the other figures are magnified x 265 diam.

, * Monthly Microscopical”
142 Observations on Mucor Mucedo. Tou aaa tame

plasma (germinal matter), and continuous with that in the tubular
stem. If a little more advanced, the head has enlarged, the con-
tents are more differentiated, and a rather dense granular mass
occupies the interior with a still denser mass towards its centre,
this showing, in many cases, a pale cell within, or perhaps several,
the plasma still communicating with the filament on which the head
is expanding (b); on another filament we may find the pear-shaped
head covered with closely applied dark spores, somewhat variable
in size, those towards the neck often of an oblong or irregular
shape (2), and the “core”? with the stem darker in colour and
denser in structure.

Various effects may have been noticed according to the parti-
cular head under examination. If sufficiently matured, on the
approach of water, the outer membrane enlarges, suddenly bursts,
and a grumous semi-cellular substance flows out (w) at the same
time that the contents of the tube pass up into the head; when
well-emptied, sundry cells come into view, seated close to the inner
surface of the membrane or still deeper within ; there is no septum
visible between the head and filament. At a later period, as
growth progresses, within are numerous rounded granular cells of
nearly equal size as well as the hyaline cells, a globular head fills
the centre, and the outer surface is seen freely covered with fine
points (¢); a little below the head may be noticed a very faint line
which marks the pot of attachment between the “core” and the
outer membrane. I find no direct septum through the filament.
Under compression the outer membrane shows hexagonal areolar
structure, and this also is occasionally evident at a later period on
the membrane of the “core” or column. When rather more ad-
vanced, well-marked spores are seen on the surface, which, by
making their way towards the free surface, have ruptured the fine
outer membrane, which may sometimes be found still retaining its
hexagonal areas (d), but generally broken up entirely, the small
points lying scattered about, whilst within the “core” everything,
in well-nourished healthy plants, seems in activity. The hyaline
cells are still seen, and if the specimen be ruptured these will some-
times float out with fine molecular matter, which fills the “core,”
and on being set free exhibits active molecular movements, though
I have not been able to satisfy myself of any circulation proper of
this molecular matter in the stem.* The globular spores adhere
by contact for some time while the ripening takes place, and
eventually fall away, leaving the central column collapsed but

* The circulation may be described as of two kinds: one general, the contents
of the tubes of the mycelium, enclosing air-spores of varying shapes and sizes,
sweeping somewhat rapidly and irregularly along the threads, even for consider-
able distances; the other, special, tie small granules moving slowly along and

round the fine threads, forming a loose net-work in the interior of many of the
tubes ; no mantle or other fluid was seen in conjunction with them.

Dea ceph Lo Observations on Mucor Mucedo. 143
adherent to the stalk, of a brown tint with often a ragged outline
towards the neck. If one of the nearly ripe heads be viewed from
beneath, the edges of what on a side view appeared as a more or
less globular body, are seen to be folded in towards the expansion
of the stem as if a solid body, as the closed hand, were pushed into
a bladder partly filled with water, or somewhat like a raspberry.

What has taken place seems to be this:—The “ core” and outer
membrane are at first closely applied, but as growth proceeds
germinal matter is formed between them, whilst in their expansion
the junction remains near the neck, the space between the two
membranes becomes gradually filled with a fine cellular structure,
the remains of which are seen afterwards on both surfaces, and here
the spores are elaborated, the central “core” keeping up the supply
received through the rootlets, or perhaps even the surface of the
mycelium. The contents in the “core” retain their connection
with the stem, differentiation, in some of the heads at least, pro-
ceeds, and larger denser cells with several nuclei or daughter cells
are formed, these when perfected being found with the ordinary
spores; they are figured at (e), and cannot well be confounded with
the others. Of ther further history, as yet, I know nothing.
Whether they may turn out to be an unknown sexual condition of
the ordinary spore, or the phase of another form of plant suited for
growth in media where the chemical constituents have been altered
by the germination of the original plant or resting spores, is doubtful.

Whilst endeavouring to obtain a clue to this inquiry, some of
the mycelium was taken from the ripe cherry with a few perfect
plants or heads attached, and when under examination a drop of
water was allowed to run under the cover, suddenly the whole field
was flooded with minute bodies, enough even to confound a stanch
Heterogenist or delight a Panspermist. I had not seen them hitherto.
They were of various shapes, round, oval, oblong, with blunted
ends, naviculoid, some united at their bases, and moved freely in the
mingled fluid (f). With high magnifying powers, and under
various methods of illumination, the cause of the movement was
undiscernible.

The question naturally arose, Whence came those schizonema-
tous (?) bodies,—did they belong to the mucor,—were they sexual
representatives,—did they arise from the development of large
spores or cells (e),—were they parts of another genus or species, &¢.,
for I did not regard them as ordinary bacteria ?

Experiments seemed the only method likely to determine this
point, at least in part; they have hitherto failed in my hands, as
will be seen, but are still under consideration.

Searching over the same slide, a few ruptured integuments of
spores were seen (/), and with some of the somewhat oblong
spores (2) from near the neck were noticed a few cells of a deli-

144 Obser. tions on Mucor Mucedo. — [ Monthly, Microscopical

cate outline, in chains, as Torule (7). In all the examinations—
and they were very numerous—excessively few of these chain-
spores were seen, whilst the field was often suddenly flooded by
the schizonematous (?) little bodies, (?) bacteria.

Examining the ordinary ripe spores with medium and high
powers, the surface was noticed as (irregularly) finely corrugated.
This is mentioned as any point elucidatory or diagnostic of one
kind of spore compared with another, should such difference be
found confirmatory, is of value when we approach the examination
of atmospheric germs, and those of lichens of similar size and colour.

In the following experiments was sought, firstly, the germi-
nation of the spores from one of the ripe and unripe heads on a
different fruit; hence one of each, so far as I could judge by close
examination, was placed on a strawberry, on a white gooseberry,
and on a red gooseberry, all being carefully wiped, the latter having
had the skin punctured at one spot where the ripe spore was placed.
These were set together in a glass vessel covered with a glass top,
and put aside in a semi-dark place in my room (shelves with a sheet
of newspaper fastened in front). In twenty-four hours, by hand-
lens, no visible change; in forty-eight hours the ripe head had sent
out a few filaments in the red gooseberry; the unripe head was
removed with fine forceps; no change of the spores on the other
fruits. Very little moisture had exuded from the puncture of the
skin in the red gooseberry. In seventy-two hours the whole vessel
was lined with a most charming crop of mucor-heads in all stages
of growth, mostly adherent by their rootlets against the sides of the
vessel ; the other fruits were covered with the mycelium only, show-
ing no germination of the spores which had been placed on them.
They were carefully removed, with the mycelioid threads upon
them; an examination was at once made of very many of the little
plants, and the red gooseberry taken out. The part where it rested
in the vessel was softened and somewhat decomposed, very moist,
and covered with a thick byssoid matting. The juice beneath
(about two large drops) was at once examined for the little schizo-
nematous bodies; sure enough they were there, but very few in
quantity compared with those from the mucor on the cherry.
Some from the mycelium on the cherry was at once set in some
juice from a fresh ripe red gooseberry on prepared slides with thin
covers, one slide set in a glass vessel and placed in a dark cupboard,
the other in the light, z7.e. in a deep tin vessel with a glass cover,
each having wet rag at the bottom. At the same time, for com-
parison, a slide containing yeast-cells from a fresh cask of beer, with
small cells and numerous genuine bacteria and active molecules,
was set in the cupboard, under the same conditions; twenty-four
hours later the spores from mucor had become somewhat larger in
both, and the movements less free in the slide placed in the dark.

eT Rek ae Observations on Mucor Mucedo. 145

In forty-eight hours the slide from the cupboard had become some-
what dry; a little fresh juice was added at the edge of the cover,
and by gentle manipulation made to run under it. On the slide
from the tin vessel the little bodies had grown every way: many
had budded at the extremities and remained united; some had
formed a short filament of two joints; others three, and contained
either oil-globules or nuclei; very many had become decidedly
naviculoid, others had kept their original contour and united in
clains or little groups (&); the movements of the naviculoid, blunt
and oval shaped bodies continued, but much less active; the others
were motionless. On the fourth day (ninety-six hours), the bright
spots in the centres of many had a vacuolated appearance, which,
under 750 diameters, is figured at s. Were they degenerating ?
They are still under notice. Those in the slide in the dark cup-
board had evidently faded, and at this period were smaller than
when set aside. In appearance they resembled greatly the small
faded yeast-cells in the slide from beer. I think it would have
been almost impossible to distinguish them in this condition,
though inthe early stage there seemed considerable difference in
very many, if not most of them. Hence to return to the examina-
tion of the little quantity of fluid in the glass vessel from the
gooseberry: the second day it was watery, though still red; care-
fully examined, it furnished a few large rather dense spores or cells,
with sometimes two or three brownish oval nuclei or secondary
cells in the interior, mingled with many very minute dark granules
and somewhat larger bright globules with a dark contour, numerous
on the outside of the cell-wall, and not at all of the appearance of
oil-globules produced by exudation (p), as seen at 750 diameters.
Besides, a few of the mucor spores were noticed, which much
resembled yeast-cells, or rather the cells from the unripe heads (4),
but were of a dark colour (q). In ninety-six hours many little
bodies, differing from the previous ones, though probably derived
from them, were found in this fluid; they were generally sharp at
each end, of a bright pale yellowish colour, and in mostly small
and large groups, exhibiting no movement (r). They were set
aside with fresh juice, and showed no change on the eighteenth
day.

Secondly, experiments were made in reference to the germinal
matter or protoplasm :—T wo unripe heads, one rather less so than
the other, were placed on a slide with fresh gooseberry juice and
covered : the heads burst almost directly, and parts of the contents of
the stem flowed out at the broken end ;—the eighteenth day, having
been kept in a moist atmosphere in the light, there was no material
change in the viscid plasma of either the head or the stem, save in
one of the former, dense oil-globules had exuded from the edges.
At the same time, two rather riper heads were treated in the same

146 Observations on Mucor Mucedo, — [Monthly Mictoscopteal
way. The granular spores, though partially separated from one
head, are still adherent, and have enlarged; two of the most out-
side germinated on the sixth day; no further change on the
eighteenth day. The whole of the spores in the riper head had
germinated in twenty-four hours, and in forty-eight hours the
appearance was that of a diminutive mop-head with tags reaching
to the handle; the mycelium soon crept beyond the edge of a
$-cover, and on the sixth day had numerous ripe heads at the edge
of the thin covering-glass. The large threads were filled with
fine granular matter, a little denser at the growing points and with-
out ampulle or enlargements (7).

The circulation of the granular contents was long watched in
several of these:threads’ heads, and seen for the first time on the
seventh day; the granules had the appearance of the swarming
spores seen in the ends of Clostervwm, &c.; some of the threads
were divided by septa at this period, others contained a loose, fine
network of threads.

At this time the yeast-cells in the slide set aside had much
degenerated ; those which retained their usual condition had formed
short chains, the central cell, much the largest, bemg filled with
fine granules or nuclei; the jointed bacteria remained as at first,
and the small granules showed no active molecular Brownonian
movements ; evidently the conditions were not favourable for deve-
lopment. Several other experiments were made.

In this article sundry points have been noticed: the growth of
the spores outside the columella and within cellular areole between
the outer and inner membrane; the outer membrane, formed
originally with hexagonal areas, the inner by the membrane which
constitutes the wall of the “core,” and these united at one part of
their course; communication of the germinal matter in the core
with that in the stem and rootlets; its circulation in the mycelium ;
sundry markings or corrugations on the ordinary ripe spores; the
appearance of larger cells in some heads, from the further develop-
ment of the germinal matter in the “core;” the non-conversion of
the grumous contents of unripe spores or heads into bacteria, or
any other form of life, when placed in a medium in which the ripe
spores readily germinated; the question opened as to the origin of
certain free schizonematous or bacteroid bodies, their gradual deve-
lopment in parts, and of the larger cells in the media used for the
regerminating experiments, &c.

In this paper all allusion to experiments on animal tissues or
fluids has been expressly avoided.

Being fully aware of the doubts that may be raised in all similar
experiments, by enclosing unsuspected floating spores or living
germinal matter in such a state of division as to defy proof by the
highest powers in the hands of microscopists ; hence just such pre-

Monthly Mic ical a
eee Detection of Corpuseles. 147

cautions were taken as seemed of real utility in a question so
balanced. Having no theory to support, the general descriptive
evidence—prefacing may be future experiments—is left to those
who like to apply the missing “modes of motion.” Unfortunately
we, who are only at the threshold of inquiry, to suit our theories
are apt to question somewhat dogmatically, plan rules, and set
restrictions on the ways and means of Him who has been working
for ages; hence the contradictions which so continually betray our
ignorance, whether as regards the past, present, or future of the
smallest living speck, or the complex organism of the most sentient
and intelligent being. What was the first “mode of motion,”
—what the first atom capable of “ evolution,”—of converting sur-
rounding material to its growth,—of reproducing its like, &c.?
Echo will reverberate round the world, chased by its hollow sound,
an empty answer, while Time gathers generations of the wisest.

IV.—On the Detection by the Microscope of Red and White Cor-
puscles in Blood-stains. By JosnpaH G. Ricnarpson, M.D.,
Microscopist to the Pennsylvania Hospital.

Since the elaborate researches of Gulliver and Carl Schmidt, in
regard to the exact variation of size among the blood corpuscles
in different species of vertebrates have been laid before the pro-
fession, microscopic examination of blood-stains has assumed an
importance in medical jurisprudence far greater than any or all the
other methods as yet suggested for the discovery of crime in cases
where such recognition depends upon the presence of blood. So
characteristic, indeed, 1s the combination of red and white cor-
puscles in the circulating fluid that one might almost as well pretend
to doubt the infinite probability that a countless procession of
creatures, bearing every appearance of being men and women, was
actually composed of members of the human family, as to dispute
the fact that a drop of liquid exhibiting the normal corpuscles in
their usual abundance, when examined with a suitable power of the
microscope, did in reality consist of blood.

When, however, as most commonly occurs, the microscopist is
called upon to determine the presence or absence of blood in a dried
spot upon cloth or other material, and especially if the exigencies of
the case demand a decision whether, if blood, it is that of a human
being, the task often becomes extremely difficult, and has hitherto
been abandoned as insurmountable by some authorities upon the
subject; while others, more sanguine of general success as they

148 Detection of Red and White — | Monthis, Microscopic

seem to be, yet fail to give the minute directions which would alone
enable their readers to follow even at a distance in their footsteps.

Being recently called upon to investigate this subject, as con-
nected with a criminal trial in one of the Eastern States, I was led
to some extended researches upon the dried blood corpuscle, develop-
ing some of their characteristics which may prove useful to other
microscopists engaged in similar studies, and contribute to extend
the field of the instrument as an aid to medical jurisprudence.

As intimated above, several of the standard authorities, among

whom may be cited Taylor, of London, Briand, of Paris, and Wharton
and Stillé, of this city (Philadelphia ), in their respective works on
‘Medical J urisprudence, assert that, with proper care and practice,
one can generally distinguish the characters of corpuscles in dried
blood-stains ; as, for instance, the latter of these gentlemen informs
us, on p. 678 of the edition of 1860, that—‘“ When the tissue has
been well soaked (in solution of sulphate of soda) the stams may be
carefully detached with a scalpel and the liquid placed upon a
glass slide, and immediately covered with another one. .
A portion of the globules will be found free; while others will
be attached to the fibres of the stuff, but they will preserve their
natural colour, volume, and more or less their Shape also, to such
an extent, however, as to be readily recognized.”

But, on the other hand, we find that many microscopists | who
have specially investigated the subject, entertain a different opinion
as to the facility with which the problem can be solved; thus, for
example, Dr. Andrew Fleming concludes his able monograph upon
blood-stains, republished from the columns of the ‘ American
Journal of Medical Science’ for January, 1859, with the acknow-
ledgment :—‘‘ From the experiments which I have made during a
period of several years with blood belonging to different animals,
when dried for a length of time and moistened again, I am forced
to admit that great difficulty arises in attempting to fix its origin by
the comparative size of the corpuscles; and again, that the blood
of ovipara, when kept for several weeks, does not present the pecu-
lar elliptical corpuscles found in fresh blood in a form sufficiently
perfect to justify me in declaring positively whence it proceeds.”

Dr. B. W. Richardson, of London, in his work on the ‘ Coagu-
lation of the Blood,’ p. 459, observes :—* Much has been said and
written about the differential diagnosis of the blood of man and of
other mammalia. For my own part, I am free to say that if
specimens of blood from man, from the ox, sheep, pig, guinea-pig,
dog, cat, or rabbit were placed before me, I should be utterly unable
to say with precision, from any examination which I could institute,
chemical or microscopical, from which of these animals the specimens
were derived.”

Professor J. Wyman, of Harvard College, one of our most skil-

*ournal, Sept. 1, 1363. Corpuscles in Blood-stains. 149

ful American microscopists, gives, as the result of his experiments
upon dried blood: *—“If a drop of blood be rubbed on a piece of
glass, as by drawing a bloody finger across it so that the disks are
deposited in a stngle layer, and then allowed to dry, they are readily
recognized even in the dried state; but when allowed to dry in
masses, I have failed to determine their presence. ‘The lymph
globules, on the contrary, may be softened out after they have been
dried for months, and their characteristic marks readily obtained.”

And Prof. Virchow, of Berlin, observes : |—‘“‘ In regard to the
diagnosis by this method (difference in size of the blood globules in
mammalia), I can only endorse the unfavourable opinion of Bricke,
and I do not believe that any microscopist will hold himself justified
in putting in question a man’s life on the uncertain calculation of a
blood corpuscle’s ratio of contraction by drying.”

One of the primary steps in entermg upon an investigation of
blood-stains is the selection of a proper menstruum for moistening
the dried clot, and here at the outset we meet with a great dis-
crepancy of opinion; by some authorities pure water, which cer-
tainly has the advantage of far greater convenience in its employ-
ment, is highly recommended, whilst others who prefer saline
solutions, fixed or volatile oils, &c., condemn the use of water as
utterly destructive to the red corpuscles; thus, M. Ch. Robin, of
Paris, in a translation of one of his articles on the subject ‘in the
‘New Orleans Medical News,’ December, 1857, is credited with the
following statement :—‘“ By scraping the small crust (of a blood-
stain), as seen under a simple magnifying glass, and receiving it
either in the shape of dust or small fragments, under the ordinary
glass object-carrier, we found that water discoloured (decolourized ?)
the spots or the substance taken up by scraping, that the latter
takes a greyish hue and swells up a little; the water, on the other
hand, becomes slightly red, takes up the colouring matter of the
red globules of blood, dissolves the colourless elements, and leaves
atter this action no visible particles behind, such as nucleus or
granulations.” Prof. Robin declares the residuary grey mass to be
“composed entirely of fibrin.”

This opinion in regard to the action of water on the red discs
seems to be one widely accepted at present, for we find Prof. Austin
Flint, jun., of New York, observes, on p. 116 of the first volume of
‘The Physiology of Man,’ published in 1866 :—“ If pure water be
added to a specimen of blood under the microscope, the corpuscles
will first swell up, become spherical, and are finally lost to view by
solution ;” and Prof. Lionel Beale teaches, on p. 169 of the
‘Microscope in Practicai Medicine, that the red corpuscles are
simply “masses of soft viscid matter, perhaps of the consistence of

* Bemi’s ‘ Report of the Webster Case,’ p. 91.
* Virchow’s ‘ Archiy.,’ band. xii., s. 336.

150 Detection of Red and White Monee

treacle, composed of hemato-crystallin,” and while admitting that
the outer part of each mass may be of firmer consistence than the
interior, denies that in mammalia generally they possess a true cell-
wall, so that, if his doctrine be correct, the chance of detecting any
isolated red corpuscles in a mass of blood clot, howsoever moistened,
seems almost as hopeless as the search after individual rain-drops in
a cake of melting ice.

In the progress of some researches upon the distension of the
white blood-cells when acted upon by water,* I have often inci-
dentally noticed that many of the red corpuscles become, after a
time, so transparent and colourless by the solution and abstraction
of their “heemato-crystallin,” that they are quite invisible under a
power of 400 diameters, and appear to be in reality dissolved as
stated by Prof. Wyman, M. Ch. Robin, and other authorities; yet
when closely scrutinized under a 5), immersion objective, their faint
transparent outlines can still be detected; thus confirming Prof.
Beale’s assertion} that “with the highest powers not only do we
meet with extremely minute corpuscles, but many of them are so
very transparent that they could not be seen at all under a low
power. Jixtremely transparent bodies are demonstrated under
high powers, which would certainly be passed over by those in
ordinary use.”

This observation appeared to have such an important bearing
upon the subject of my present paper that I entered upon its
special investigation, which I propose briefly to detail, promising
that while the results seem to prove a very marked difference in
density, if not in constitution, between the external and internal
portions of the blood discs, I do not consider the data here collected
sufficient for controverting the opinions of those experienced histo-
logists who deny to the red corpuscle a proper cell-wall.

Expt. 1—Five drops of blood drawn with a cataract needle
from the tip of the finger was stirred with half a fluid-ounce of
river-water 1n a conical wine-glass, which was carefully closed
against the entrance of extraneous matters and set aside. ‘T'wenty-
four hours after a scanty sediment, whitish in colour, was visible in
the bottom of the vessel, and a small portion of this deposit ex-
amined under the .}., showed that it was chiefly composed of red
blood discs, exhibiting no appearance of rupture, globular in form,
quite colourless, and so transparent that very close attention was
necessary for their detection. Similar results were obtained at the
end of forty-eight hours, but at the end of seventy-two hours many
of these globules were obscured by the formation of Vibriones and
Bacteria, which were developing with great rapidity.

Kapt. 2.—A thin film of human blood was spread out upon a
slide, allowed to dry, covered with thin glass, and then adjusted
under the ,; after finding a suitable field which contained a white

* ¢Pennyslvania Hospital Reports,’ 1869. t Op. cit., p. 170.

TRE. oe Corpuscles in Blood-stains. 151

blood corpuscle surrounded by rouleaux of red ones, water was in-
troduced at the edge of the cover by means of a thread from the
reservoir. As the wave of fluid, deeply tinged with colouring
matter it had dissolved, crossed the field of the microscope, the cor-
puscles were, for a few moments, obscured, but in a short time the
white cell reappeared, and soon after the very faint but unmis-
takable outlines of the red discs again became visible. This experi-
ment was varied by irrigating some fields exhibiting isolated red
corpuscles, and others where by crowding together they had
formed an apparently homogeneous clot, in every case with the
same result where a high power was employed; with the 4-inch
objective, however, I was unable to satisfy myself of the existence of
these eviscerated discs. By careful measurement with the cobweb
micrometer, the white corpuscles were found to first diminish
slightly on contact with water, and afterwards to expand to rather
more than their original diameter, while the red discs appeared to
suffer a permanent decrease from about 3o55 to ssbo of an inch
ACLOSS.

Expt. 3.—Some minute fragments of dried blood from a stain
made upon a piece of muslin about three months before were placed
upon a slide and adjusted on the stage of the microscope; after finding
a suitable portion of clot with a thin bevelled edge, water was intro-
duced at the margin of the cover and allowed to flow very slowly
towards the chosen fragment; when this was reached by the wave
of fluid a remarkable appearance of boiling up from its centre was
presented for a few moments, and then as the tinged liquid was re-
placed by pure water an aggregation of compressed corpuscles, very
faint and colourless, but yet of unquestionable distinctness, became
apparent ; a few straight interlaced filaments of fibrin were visible,
and at intervals the granular spherical lymph globules occurred
among the other elements; these white cells frequently became
detached, and floated freely around the edges of the clot, where,
as well as whilst still embedded, they were so much more readily
recognized with a low power that I suspect they have often been
mistaken for the red discs. By introducing at the margin of the
cover, a minute portion of iodine solution,* the outlines of the de-
colourized corpuscles are rendered far more obvious, and can often
be distinguished even by inexperienced observers.

In a similar manner the blood of an ox, sheep, pig, chicken,
turkey, and canary bird, most of them dried in a thin film upon a
slide, and all dried in a mass upon paper or muslin, were carefully
examined, and little difficulty found in distinctly perceiving that the
colourless stroma with its “straight or slightly waving filaments,
sometimes more fibrous, sometimes more wrinkled and homo-
geneous, ¢ so long mistaken under lower powers for a mass of
fibrin, was actually an aggregation of decolourized red corpuscles,

* Beale, ‘How to Work with the Microscope,’ p. 207. + Virchow, loc. cit.

152 Detection of Red and White [erm Bese oa
with rare filaments of fibrin, and white blood cells imbedded in it.
It is true that the older microscopists who rarely obtained first-rate
definition with their lenses magnifying much beyond 500 diameters,
were probably wise in recommending that none but the most expert
should attempt a decision between the blood of various mammalia,
even when fresh, for the difference between an apparent magnitude
of y/o and 35 of an inch may well be counted too minute to lightly
determine a question often so momentous; but as during the last
three or four years opticians have furnished immersion lenses of
zs and 35 of inch focal length, which with the highest eye-piece
give an amplification of about 2500 and 5000 diameters respectively,
thus rendering, with the former, the apparent size of a red disk
from fresh human blood five-sevenths of an inch, while that of a
corpuscle from ox blood is but half an inch across, and consequently
little more than half the area as seen upon the stage, it seems as if
any careful observer might now, with the aid of such objectives, be
qualified to pronounce a positive opinion.

It has been plausibly objected, however, as by Prof. Virchow
in the extract above quoted, that since the diagnosis of the different
species of mammalian blood depends solely upon the relative size of
the red disks, variation in the rapidity of desiccation may sometimes
cause dried corpuscles to so deviate from the ordinary degree of
contraction during that process as to lead the microscopist, who
relies upon the characteristic of magnitude only, into serious or fatal
error. In order to test the truth of this hypothesis, drops of blood
from the finger, deposited upon pieces of muslin, were dried under
various circumstances ; fragments of the stain removed by scraping
were then moistened with pure water, and from each variety of
desiccated spot, ten corpuscles selected without regard to size, as
among those which had best retained their normal circular outline,
were carefully measured with the micrometer. Upon comparing
the averages of these, as appended below, it will be seen that the
difference in the mean diameters does not amount to ygp/gn0 Of an
inch ; in no instance was a circular red disk observed to exhibit
such an approximation in magnitude to those of ox blood, as could,
by any possibility, render its different origin a matter of doubt.

TABLE.
Ten blood corpuscles moistened with water from a clot on muslin which had

been dried :— DIAMETERS.

Max. Min. Mean.
In the open air at ordinary temperature .. gpg ++ gees +--+ Beso
Before ahot fire ... ... .. « «oF o geage -* Pee -°* Beee
In the afternoon sunshine... .. .. ws) aging spss +. sesa
Ina damp, dark closet .. .. .. «2» gece ao

‘These various experiments appearing to indicate the absence of
any tendency in the red blood disk to undergo expansion, I was led

M : . e e
Sener, Geek Corpuscles in Blood-stains. 153

to make the following calculation, which tends to show that the
outer portion of the corpuscles (whether it be merely condensed
viscid material, or a true cell-wall composed of membrane distinct
in composition from hemato-crystallin) is of an inelastic character.
Ten red globules of freshly-drawn human blood magnified almost
1800 times were measured with the micrometer while standing on
their edges, both in length (as so placed) and in thickness, their
mean diameter being found equal to 33'rg and their mean of greatest
thickness tz455 of an inch. From these data, estimating the total
surface of the globule as approximatively equivalent to ninety-six
one hundred and sixty-firsts of a ring ‘00029886 in outside
diameter, and ‘00007478 of an inch thick, plus double the super-
ficies of a segment with a versed sine of *00003739 cut from
a sphere having °00017718 radius, I calculated the area of the
hypothetical cell-wall to be -00000017932 of a square inch ; by
further computation, it was found that this amount of membrane
would cover a globe °00023891 of an inch in diameter, which
number so nearly coincides with that expressing the diameter of
the red disk, when rendered spherical by the action of pure water,
viz. *00023332 (<s's¢) of an inch, that I think we may fairly con-
clude that, although the shape of the corpuscle is thus altered, its
parietes undergo no real dilatation in the process; further, the cor-
rugated appearance assumed by the corpuscle when any portion of
its internal constituent is removed by exosmosis affords some
evidence that, however much the cavity is decreased, its limiting
membrane suffers no actual diminution in superficial area.

Although it must be admitted that the blood corpuscles of a few
mammals approach so nearly in size to those of man as to render
their distinction doubtful, yet for the practical testing of blood-
stains in criminal trials we will rarely find that such a decision
Is necessary, since, as a rule, justice only requires that a positive
diagnosis shall be made between human blood and that of animals
which are commonly slaughtered for food, such as the ox, the sheep,
the pig, or of birds, as for example, chickens, ducks, &c., in regard
to all of which I believe when the disks have not undergone dis-
integration, a first-rate s!; inch objective will enable us to determine
easily and beyond all question.

I would suggest to any one about undertaking such an in-
vestigation, that he first accustom himself to the appearance of
decolourized blood corpuscles, and at the same time test the power
of his instrument by repeating Experiment 3rd, as detailed above,
on a fragment of blood clot recently desiccated upon paper or glass.
Iixperience has shown that dried stains upon hard, smooth surfaces,
such as buttons, studs, &., most readily exhibit the corpuscles ;
next to these in case of detection, are stains upon paper collars or
euff=, and upon highly glazed linen; then those upon unstarched

VoL. II, M

154 Detection of Corpuseles. vou

muslin or linen; and lastly, those upon cloth and other woollen
fabrics. In order to be forearmed against the objections of in-
genious counsel, he should in murder cases, wherever practicable,
be provided with spots made before witnesses, with fresh blood from
the corpse upon different unstained portions of the identical articles
of the supposed murderer’s clothing, and also with specimens of the
blood dried in a thin film upon glass slides, for the purpose of dis-
proving any hypothesis of leucocythemia, or other blood diseases,
which might alter the normal character or relative proportion of
the blood elements.

In examining the moistened clot, great care must be taken to
avoid any movement of cover upon the slide, which, when it occurs,
often rolls the interposed disk into an apparently homogeneous
mass; and it is advisable to keep up a current of fresh water, at
least, until all tinge of colour is removed from the clot, otherwise
none but the granular lymph corpuscles can be visible. Should
any doubt remain as to the identity of these bodies, it can be set
at rest by treating them with acetic acid or solution of aniline, as
noted in a paper on the “ Detection of Undiluted from those of
Diluted Blood-stains,” in the American ‘ Med. and Surg. Reporter,’
Jan. 9,1869. In order to complete a chain of evidence it is probable
that the decolourized corpuscles in a fragment of clot after being
rendered more distinct by iodine, as above mentioned, might often
be demonstrated, if required in court, to intelligent jurymen, espe-
cially where as surveyors, watchmakers, or engravers, the jurors
were not unaccustomed to the use of lenses.

It may not be out of place to subjoin a comparison of the rela-
tive delicacy of the different processes recommended by medical
jurists for the discovery of blood-stains.

By the intricate and tedious method of M. Taddei,* “ A piece —
of linen or cotton, which hardly contained 28 to 30 centigrammes
(between four and five troy grains) of dried blood furnished enough
for the determination of its nature.”

A plan suggested by Dr. F. Runge, in which the iron of the
blood was tested for by ferrocyanide of potassium, is spoken of by
Dr. Fleming as being so very delicate, that a single drop of blood
sufficed for complete detection.

By spectrum analysis lately vaunted as successful when ordinary
microscopic examination fails, it is claimed that +,),,th of a grain
of dried blood may be recognized, but no clue is thus afforded to the
animal from whence the vital fluid is derived.

Through the courtesy of Dr. Linderman, Director, and Mr.
J. R. Eckfelt, Chief Assayer of the United States Mint, I was
enabled to estimate the delicacy of the microscopic test for blood, as
follows :—U pon a square of waxed paper determined by Mr. Eckfelt

* Fabre, ‘ Bibliotheque du Médecin Praticien,’ tom. xv. p. 264, Paris, 1851.

ot Microscopical Preparations. 155

on the accurate balance used for the National Assays, to weigh
exactly 48 millicrammes, I made twenty dots of fresh blood from
my finger, which, when dry, added -4 of a milligramme to the
original weight, and consequently were each on an average equiva-
lent to about °02 of a milligramme, or 32/55 of a troy grain nearly.
The fourth part of one of these spots, weighing of course in round
numbers ysig,5 of a grain, was detached with the point of a cataract
needle, and when moistened under the 4; showed many hundred
well-defined red blood corpuscles ; ten circular ones among these
measured with the micrometer averaged 375qth of an inch in
diameter, and could therefore, by this criterion of superior size
alone, be diagnosticated from the corpuscles of an ox, sheep, or pig,
- with the same feeling of certainty with which any surgeon could
testify that a perforation of the skull only half an inch across could
not possibly have been made by a bullet measuring an inch in
diameter.—Paper read before the Microscopical Section of the
Academy of Natural Sciences, Philadelphia, and communicated to
the ‘ Monthly Microscopical Journal’ by the author.

V.—On the Staining of Microscopical Preparations.
By Dr. W. BR. M‘Nas.

1. Staining with Acetate of Mauvine.

A. This can be used with very good effect in staining thin sec-
tions of wood. If these are preserved in Canada balsam they seem
to be permanently stained, as a few specimens put up in January,
1866, are now quite as brightly coloured as they were at first. By
means of the colouring the high powers of the microscope can be
used, bringing out points of structure not easily demonstrated
without being so treated. Sections (transverse) of coniferous
woods show beautifully the structure of the punctated tissue, as
well as the junctions of the cell-walls and the thickening layers of
ligneous matter. |

B. Sections of the young stems of ivy were last year (February,
1868) successfully stained with acetate of mauvine and glycerine.*
Since then most of the specimens have faded. The contents of the
cells have lost colour entirely, but the cuticular layer of the epidermis
retains its colour, as well as the young ligneous cells. In a speci-
men now before us, the pith and the enclosed cell-contents are now
colourless, but the zone of cells in which a deposit of ligneous
matter has been formed are brightly coloured. The very small

* See ‘ Botanical Society Transactions.’

M 2

iba On the Staining of “our pe oe

eambium cells bounding this layer are quite colourless. In the
outer layer of cambium the cells become large, more like the bark
cells, and here and there a few bundles of thickened cells can be
seen, brightly coloured like the others. These, I suppose, are bast
cells. A few of the laticiferous canals, described last year in
‘ Botanical Society Transactions, are lying close to these small
patches of bast cells, but far more frequently they he close to the
small cambium cells. The layer of cellular tissue, external to
the bast cells, is not coloured, and their thin walls contrast strongly
with the greatly thickened cell-walls of the epidermal cells, on
which the mauvine does not seem to exert any influence. The
cuticle is well marked as a bright purple external layer, contrasting
strongly with the colourless thickened cells on which it rests.

If any reliance is to be placed in the results obtained by stain-
ing specimens with mauvine, there is one very important point I
wish to mention. Schacht* states that the so-called intercellular
substance, joining the walls of contiguous cells together, forms on
the free surface of the cells what is known as the cuticle. By
some the existence of this intercellular substance is denied ; and by
careful examination of many specimens now before me, I can find
no trace of any such material. The cuticle is brightly coloured,
and if the same material existed as intercellular substance between
the cells, a ecloured layer should be seen between each of these cells, .
but none can be seen. If, then, the test of colour can be relied on,
either intercellular substance does not exist, or else its composition
is peony different from that of cuticle.

2. Staining with Beales Carmine Solution.

When small portions of vegetable tissue are soaked in the car-
mine solution, only those cells containing protoplasm appear stained.
The nuclei and the granules in the protoplasm seem alone to be
affected. ‘The depth of colouring depends, then, on the number of
granules in the protoplasm and the size of the nucleus.

A. Haperiments in Phalaris canariensis.—The rootlets of ger-
minating seedlings of Phalaris canariensis were placed in a solution
of carmine. When examined about twelve hours afterwards, the
extremities of the rootlets were found to be very deeply coloured,
while a faint tinge was visible along the other parts of the rootlet.
Under the microscope the structure of the growing point of the root
was beautifully seen. First a series of loose cells are seen at the
extremity, continuing a short distance above the growing point.
A very few of the most internal cells seem to be slightly coloured,
the external ones being quite colourless. This mass of cells forms
a regular sheath-like cap to the growing part of the root, very
similar to the highly developed pileorhiza of Lemna. A well-

* § Grund. der Anat. und Phys. der Gewachse.’ p. 29.

er ee Microscopical Prepurutions. 157

marked line of separation can be seen marking the boundary of the
growing point, the cells being deeply coloured for a short distance.
‘The cells are densely filled with granular protoplasm, and each
contains a very large nucleus. A little higher up the colouring
gets very faint, and at last is confined to the interior of the rootlet,
where a few nuclei are seen closely surrounding the spiral vessels.
The growing point of a root of the Phalaris, when treated with
carmine, shows—Ilst. A number of large loose cells at the point,
extending like a pileorhiza, a short distance from the extremity ;
2nd. The internal cells of this sheath are coloured, and therefore
contain active protoplasm; 3rd. The growing point of the root is
very deeply coloured, the protoplasm is densely granular, and con-
tains a large nucleus; 4th. A very short distance above the growing
part the cells are only marked by an occasional nucleus; and, lastly,
the nuclei are only found close to the spiral vessels.

B. Experiments with Sinapis alba (White Mustard)—Series 1.
—These were begun in February, 1868, and consisted in germina-
ting white mustard both in water and in soil, and then examining
the structure after staining with carmine. During the first stages
of germination of the seeds, germinated both in soil and in water,
no trace of staining could be found, and it was not till the radicle
had attained some size that the point of the root became stained
with the carmine. If we can depend on such tests, we must con-
clude that the germination of the white mustard is not dependent
on the formation of new cells, but merely on the growth and en-
largement of the pre-existing cells. Whenever growth by the
formation of new cells had taken place these cells could be rendered
distinctly visible by the action of carmine, the parts above this
remaining white, although submitted to the action of carmine under
precisely the same conditions.

Series 2.—A much more extensive series of experiments was
tried in December, 1868, by growing white mustard for a short
time in carmine solution. After the plants were about two inches
in height carmine was added, and they continued to grow for
several days after. The youngest stages of development failed to
furnish stained specimens, and it was only after a few days that the
young radicles could be stained. ‘The structure of the root is more
complex than that seen in the Phalaris canariensis, but agreed in
every essential point. The loose cells were seen at the tip, the
growing point densely coloured, the colouring becoming less and
less till it was no longer visible. The protoplasm near the growing
point is densely granular, and the nuclei very large, filling up from
one-fourth to one-third of the whole cell.

Transverse sections of the young root, above the growing point,
showed the arrangement of the cells very clearly. In the centre is
a mass of small thickened cells, containing protoplasm and nuclei

158 Remarks on the “Journal, Sept. 1, 1809.

in many cases. Immediately outside this are three layers of large
cells with protoplasm and large nuclei. Surrounding this layer is

a single series of small cells placed very close together, containing

a densely granular protoplasm, and very large, often two, nuclei,

probably a cambium layer. External to this is a layer of epidermal
cells, not apparently thickened, the whole being enclosed by what
appears to be a thickened cuticle. Parts of the young radicle are
covered with hairs. These could be very clearly seen, and their
mode of formation observed. I cannot detect any thickened cuticle
at those parts where the hairs are developing. The hairs are direct
prolongations of the epidermal cells, and in general the contents
and nucleus can be seen to have been carried forward, and occupying
the centre of the hair. The sections I have now before me, show-
ing the hairs, are much farther from the growing point than that
described above as having a thickened cuticle, but no cuticle is
visible. The hairs elongate very much, without dividing; the
nucleus in most was wanting, although the granular contents re-
mained. Here and there large spaces filled with cell-sap were seen,
and in one instance the contents of one of these long cells were
seen oscillating backwards and forwards for some time. The use of
the staining process does not seem to be attended with any great
difficulty, and, I have no doubt, important results may be obtained
by careful study of its action on germinating plants.—Transactions
of the Botanical Society of Edinburgh: paper forwarded by the

author.

VI.—Some Further Remarks on an Illumination for Verifying
the Structure of Diatoms and other Minute Objects.

By F. H. Wenuam.

ADDITIONAL observations with the principle of illumination, sug-
gested in this Journal for July last, No. VII, have shown that it
displays many objects with a degree of truth not obtainable by any
other means; for it must be borne in mind that it involves this
singular peculiarity, vz. the whole of the light is conveyed into
the interior of the object itself, which appears self-luminous in a
jet-black field. In all other methods with which we are acquainted,
light is either directly transmitted, or thrown on the surface, the
glare from which in many instances prevents the interior structure
from being seen.

The cut is an arrangement illustrative of this principle of ilu-
mination. a is a right-angled prism, or which may be a hemi-
spherical lens, as shown by the dotted lines; 6 is a condensing-lens,
behind which, and also below the prism, are stops c and d; e is

ao eee Structure of Diatoms, &c. 159

the light which enters direct into the vertical face of the prism,
and is reflected upwards through the under-side by means of the
mirror f. ‘The diagonal face of the prism is surmounted by a

dark box, through which is introduced the microscope body, with
object-glass, g. ‘The side of this box has a sliding shutter opening
level with the face of the prism, for the introduction of slides and
detached objects. |

The two lights simultaneously transmitted through the rectan-
gular faces of the prism will both be totally reflected from the
diagonal surface, and if this is clean not a trace of light will be
seen in the dark chamber. A fragment of thin white paper laid
on the prism will be quite invisible under the microscope. If now,
with a needle-point, we touch the paper with a minute drop of
water, so as to bring a spot in aqueous contact with the prism,
this will destroy total reflexion at the part, which will appear
brilliantly luminous.

If a water-snail, aquatic larva, or caterpillar is placed on the
prism with a drop of water, the whole of the interior anatomy is
distinctly seen, as the light enters the part only of the object in
contact with the glass, and is diffused throughout the body. When
objects mounted on ordinary microscope slides are to be viewed,
some water must be placed on the back of the prism; and if the
object is a moving one, it may be laid on a blank slide, and this
traversed over the prism with water between.

Though this arrangement displays large transparent objects,

160 Structure of Diatoms, &c. [Sore cae

magnificently, yet for the ordinary class the inexpensive plan de-
scribed in No. VII. may be employed, consisting of the truncated
lens, therein shown, cemented to an ordinary glass slide with
Canada balsam. This must be used in conjunction with the para-
bolic condenser, and the rays rendered parallel by the bull’s-eye.
Instead of water, the top of the slide may be covered with a film of
glycerine, which will not evaporate; of course this does not influ-
ence the total reflexion which now takes place from the upper
surface of the glycerine. If now filaments of plants, animalcules,
or hairs of animals be laid on the glycerine, they instantly appear
luminous. For example, a mouse-hair is acknowledged to be a
somewhat difficult object to show satisfactorily by ordinary means,
either opaque or transparently ; but viewed by this method its
structure is unmistakable. ‘There is no false glare, and the pig-
ment cells are seen in their true position in the interior of the hair,
which in fact forms the actual receptacle for the light.

But perhaps some of the most remarkable results are obtained
with the Diatoms. Though these are generally mounted on the
glass cover, yet it frequently happens that some have become
attached to the surface of the under-slide. It is these alone that
are visible by this principle of illumination. The small trun-
cated lens is made to adhere to the under-side by a film of oil of
cassia or cloves, and the parabolic condenser used as before directed.
Most perfect and apparently detached fragments of the Diatom
scale are clearly brought out, and its structure proved satisfactorily
and in a more reliable manner than by any other mode of illumi-
nation that I have yet seen, as it is only those parts of the scale in
actual contact where total reflexion is destroyed that are visible,
consisting perhaps of part of the mid-rib, and a row of dots here
and there, or square or triangular patches, according to the species,
and very frequently a little isolated group of only three or four
nodules together.

It was my intention to have illustrated some of these appear-
ances with camera lucida drawings, but I have now no time for such
pursuits ; but as the truncated lenses are inexpensive, I trust that
some one may be at the pains of employing them as a means of
investigating these objects.

Monthly Mi copical .
Journal, Sept. 1, 1869. ee

VII.—On the Rhizopodal Fauna of the Deep Sea.
By Wiuiram B. Carpenter, M.D., V.P.BS.

In a paper laid before the Royal Society at its last Sessional
Meeting Dr. Carpenter commences by referring to the knowledge
of the Rhizopodal Fauna of the Deep Sea which has been gradually
acquired by the examination of specimens of the bottom, brought
up by the sounding-apparatus; and states that whilst this method
of investigation has made known the vast extent and diffusion of
Foraminiferal life at great depths, especially in the case of Globige-
rina-mud, which has been proved to cover a large part of the
bottom of the North Atlantic Ocean, it has not added any new
types to those discoverable in comparatively shallow waters. With
the exception of a few forms, which, like Globigerina, find their
most congenial home, and attain their greatest development, at
great depths, the general rule has seemed to be that Foraminifera
are progressively dwarfed in proportion to increase of depth, as
they are changed from a warmer to a colder climate; those which
are brought up from great depths in the equatorial region bearing
a much stronger resemblance to those of the colder, temperate, or
even of the Arctic seas, than to the littoral forms of their own
region.

Tke author then refers to the recent researches of Professor
Huxley upon the indefinite protoplasmic expansion which he names
Bathybius, and which seems to extend itself over the ocean-bottom
under great varieties of depth and temperature, as among the most
important of the results obtained by the sounding-apparatus.

By the recent extension of dredging operations, however, to
depths previously considered beyond their reach, very important
additions have been made to the Foraminiferal Fauna of the Deep
Sea. Several new generic types have been discovered, and new and
remarkable varieties of types previously known have presented
themselves. It is not a little curious that all the new types
belong to the family Lituolida,—consisting of Foraminifera which
do not form a calcareous shell, but construct a “test” by the agglu-
tination of sand-grains,—which was first constituted as a distinct
group in the author’s ‘ Introduction to the Study of Foraminifera’
(1862). The first set of specimens described seems referable to
the genus Proteonina of Professor Williamson; but the test, in-
stead of being composed (as in his specimens) of sand-grains, is
constructed of sponge-spicules, cemented together with great regu-
larity, so as to form tubes which are either fusiform or cylindrical,
being in the former case usually more or less curved, and in the
latter generally straight. Of the genus Trochammina (Parker and
Jones), many examples were found of considerable size, resembling

162 On the Rhizopodal Fauna pene eee

Nodosarians in their free moniliform growth, but having their tests
constructed of sand-grains very firmly cemented together, with an
intermixture of fragments of sponge-spicules, which give a hispid
character to the surface.—The genus Rhabdammina of Professor
Sars is based on a species (the &. abyssorum) first obtained in his
son’s dredgings, of which the test is very regularly triradiate, some-
times quadriradiate, and is composed of sand-grains very regularly
arranged, and firmly united by a ferruginous cement. Not only
was this type represented by numerous species in the ‘ Lightning ’
dredgings, but another yet more considerable collection was formed
of irregularly radiating and branching tubes, which are composed
of an admixture of sand-grains and sponge-spicules, united by
ferruginous cement. These seem to originate in a “ primordial
chamber” of the same material, which extends itself into a tube
that afterwards branches indefinitely. This type may be desig-
nated R. irregularis.—Of the protean genus Lituola (Lamarck),
a large example was met with, which bears a strong resemblance to
the L. Soldani of the Sienna Tertiaries. Its nearly cylindrical
test is composed of sand-grains very loosely aggregated together,
forming a thick wall; and its cavity is divided by septa of the same
material into a succession of chambers, arranged in rectilineal series,
each having a central orifice prolonged into a short tube-—The
genus Astrorhiza, instituted a few years ago by Dr. O. Landahl,
was represented by a wide range of forms, referable to two prin-
cipal types, the one an oblate spheroid, with irregular radiating
prolongations, the other more resembling a stag’s horn, with nume-
rous dentations passing into one another by insensible gradations.
The composition of the thick arenaceous test is exactly the same as
that of the test of the Ltuola found on the same bottom; but its
cavity is undivided, and there is no proper orifice, the pseudopodial
extensions having apparently found their way out between the sand-
grains that formed the terminations of the radiating extensions or
digitations.—The genus Saccamina (Sars) is characterized by a
very regular spherical test, built up of large angular sand-grains
strongly united by ferruginous cement, which are so arranged as to
form a wall-surface well smoothed off externally, whilst its interior
is roughened by their angular projections. The cavity is undivided,
and is furnished with a single orifice, which is surrounded by a
tubular prolongation of the test, giving to the whole the aspect of
a globular flask.

The family Minionipa, consisting of Porcellanous-shelled Fora-
minifera, was represented at the depth of 530 fathoms by a Cornu-
spira folracea of extraordinary size; and at the depth of 650
fathoms by a series of Biloculinz, of dimensions not elsewhere seen
except in tropical or subtropical regions.

Of the family GLopicERInipA a considerable number of forms

Monthly Mi ical
Journal, Sept. 1, 1869. of the Deep Sea. 163

presented themselves; but, with the exception of the ordinary
Globigerina and Orbulina, these were not remarkable either for
number or size. The Globigerina-mud brought up in large
masses by the dredge exhibited the same characters as had been
previously determined by the examination of soundings; but it
included a large amount of animal life of higher types, whilst it
seemed everywhere permeated by the protoplasmic Bathybius of
Huxley, as described in the author’s ‘ Preliminary Report.’ The
Globigerinez vary enormously in size; and the author gives reason
for the belief that this variation is not the result of growth, but
that the small as well as the large individuals have, speaking gene-
rally, attained their full dimensions. He describes the sarcodic body
obtained by the decalcification of the shell, and discusses the ques-
tion whether (as some suppose) Orbulina is the reproductive seg-
ment of Globigerina, as to which he inclines to a negative conclusion.
He describes the curious manner in which the shells of Globigerine
are worked-up into cases for Tubicolar Annelids; of which cases
several different types presented themselves, the foraminiferal shells
in some of them being combined with sponge-spicules. A remark-
ably fine specimen of Teatularia was met with alive, of which the
porous shell was encased by sand-glains ; this being laid open by
section showed the sarcodic body of an olive-greenish hue, corre-
sponding with that of the Letwol# and Astrorhize, also found alive.

The family LacEnipa was represented by a large and beautiful
living Cristellaria, that closely corresponds with one of the forms
described by Fichtel and Moll from the Siennese Tertiaries, whilst
even exceeding it in dimensions.

These results conclusively show that reduction in the size of
Foraminifera cannot be attributed to increase of pressure, since the
examples of Cornuspira, Biloculina, and Cristellaria found at
depths exceeding 500 fathoms, were far larger than any that are
known to exist in the shallower waters of the colder temperate zone.
But as these all occurred in the warm area, whose bottom-tempera-
ture indicates a movement of waters from the equatorial towards the
polar region, it is probable that their size is related to the tempera-
ture of their habitat, which is found to be in like relation to the
general character of the Fauna of which they formed part. On
the other hand, as we now know that the climate of the deepest
parts of the ocean-bottom, even in equatorial regions, has often (if
not universally) Arctic coldness, the dwarfing of the abyssal Forami-
nifera ot those regions is fully accounted for on the same principle.

Besides these examples of new or remarkable forms of Foramz-
nifera, the ‘Lightning’ dredgings yielded some peculiar bodies, the
examination of which would seem to throw light upon the obscure
question of the mode of reproduction in this group. One set of these
are cysts, of various shapes and sizes, composed of sand-grains loosely

164 On the Rhizopodal Fauna. ee
ageregated, as in the tests of Letuola and Astrorhzia, which, when
broken open, are found to be filled with aggregations of minute
yellow spherules, not enclosed in any distinct envelope. ‘These are
supposed by the author to be reproductive gemmules formed by the
segmentation of the sarcodic body of a Rhizopod, in the same man-
ner as zoospores are formed in protophytes by the segmentation of
their endochrome. Of such segmentation he formerly described
indications in the sarcodic body of Orbitolites ; and corresponding
phenomena have been witnessed by Prof. Max Schulze. But in
another set of cysts, of similar materials but of firmer structure, bodies
are found having all the characters of ova, with embryos in various
stages of development. In none of these, however, does the embryo
present characters sufficiently distinctive to enable its nature to be
determined ; and the hypothesis of the Foraminiferal origin of these
bodies chiefly rests upon the conformity in the structure.of the wall
of the cysts with that of the tests of Letwola and Astrorhiza, and
upon the improbability that such cysts should have been constructed
by animals of any higher type.

Monthly Microscopical
Fournel, Sept. L 1869. ( ] 65 )

PROGRESS OF MICROSCOPICAL SCIENCE.

The Structure of the Cerebral Hemispheres.—On this subject a paper
of considerable length was taken as read at the last meeting of the
Royal Society, and will appear at length in the forthcoming number of
the ‘ Proceedings.’ The paper was by Dr. W. D. Broadbent. The
object of the investigation was twofold. First and chiefly, to en-
deavour to ascertain minutely the course of the fibres by which the
convolutions of the hemisphere are connected with each other and
with the crus and central ganglia. Secondly, to endeavour to ascertain
whether there is a constant similarity between the corresponding sides
of different brains as compared with the opposite sides of the same
brain; and should this be the case, to endeavour to trace the relation
between any anatomical difference which might be discovered and
such physiological difference as seems in the present state of our
knowledge to be indicated by the association of loss of the faculty of
language with disease of the left hemisphere rather than the right.
Dr. Broadbent’s paper related almost exclusively to the first branch
of the investigation, and the method pursued has been to harden the
brain by prolonged immersion in strong spirit, by which the fibres are
rendered perfectly distinct and fairly tenacious, so that with care
and patience their course and arrangement may be accurately ascer-
tained. Previous researches on the structure of the cerebrum have
been mainly directed to the examination of the course and distribution
of the fibres radiating from the crus and central ganglia, which have
been assumed or supposed to occupy ultimately the axis of every con-
volution, the different convolutions being connected by fibres which
crossed under the sulci from one to another. In this paper of Dr.
Broadbent’s it is shown that the commissural communication between
different parts of the hemisphere is much more extensive than has
hitherto been described, and that the fibres more commonly run longi-
tudinally in the convolutions than cross from one to another, while
large tracts of convolutions have no direct connection with the crus,
central ganglia, or corpus callosum. The details of the paper are too
numerous for reproduction here.

Photo-micrography applied to Class Demonstrations—Colonel Dr.
Woodward, of the United States Army, recently [May 31st] de-
livered a lecture on this important subject before the Biological and
Microscopical Section of the Academy of Natural Sciences of Phila-
delphia. A very long abstract of the lecture is published in the
American ‘Dental Cosmos’ for August, and from this we take the
following account :—The lecturer, after stating that it was found to
be impracticable, if not impossible, to exhibit, with any satisfactory
degree of correctness, to a large class or assemblage, such microscopi-
cal preparations as require the use of high powers, even though aided
by the oxyhydrogen or other powerful lights, explained how his atten-
tion came to be given to photo-micrography. The great field promised
by the pursuit of this branch of microscopy had already induced some

166 PROGRESS OF MICROSCOPICAL SCIENCE. [Monthly Mictoscopiem

to make attempts, among whom may be mentioned Donné, Prof. Ger-
lach, of Erlangen; Joseph Albert, of Munich; and Dr. R. L. Maddox,
of Southampton, which proved that great usefulness could be claimed
for the method. In America, Prof. O. N. Rood,* of Columbia College,
Mr. Lewis M. Rutherfurd, of New York, and Dr. John Dean, of
Boston, must be mentioned; the latter having illustrated a paper on
the spinal cord by photo-micrographs reproduced by photo-lithography,
the magnifying powers not exceeding ten or twelve diameters, while
both the former gentlemen had experimented with very high powers.
Mr. Rutherfurd had published a paper upon Astronomical Photo-
graphy,{| which contained many suggestions that the lecturer took
advantage of; and, after an interview with that gentleman, in which
the plan of constructing the objective, the use of the ammonio-sulphate
of copper, and the substitution of a properly constructed concave for
the eye-piece, were discussed, he determined to develop these sugges-
tions, and assigned to Assistant-Surgeon and Brevet-Major Edward
Curtis, U.S.A., the duty of carrying out the manipulations; to this
gentleman he expressed his indebtedness for the successful issue of the
experiments. The results attained were admitted by Dr. Maddox,
who is one of the most successful labourers in this direction in Europe,
and by other European savans, as most satisfactory, excelling any-
thing heretofore done in this branch. To obtain successful photo-
micrographs the following principles are involved :—1. To use objec-
tives so corrected as to bring the actinic ray to a focus. 2. To
illuminate by direct sunlight passed through a solution of ammonio-
sulphate of copper, which excludes practically all but the actinic
extremity of the spectrum. 3. Where it is desired to increase the
power of any objective, to use a properly constructed acromatic con-
cave instead of an eye-piece. 4. To focus on plate-glass with a
focussing glass, instead of on ground glass. 5. With high powers to
use a heliostat to preserve steady illumination. 6. Where an object
exhibits interference phenomena when illuminated with parallel
rays, aS is the case with certain diatoms and many of the soft
tissues, to produce a proper diffusion of the rays by the interposition
of one or more plates of ground glass in the illuminating pencil.
The manipulations are made in a dark room, or rather one faintly
illumined by yellow light; the light used in the process of photograph-
ing being admitted by a small brass tube, and is obtained from a
mirror, which reflects the rays of the sun from a Silbermann’s helio-
stat, through the ammonio-sulphate cell before they enter the brass tube.
When the plate of ground glass is used, it is placed between the mirror
and the condenser, the diminution of light being overcome by a bull’s-
eye, where this may be necessary, as in the use of the higher powers.
In order to enable those present to judge of the perfection of the work,
he had the representations of some of the familiar test objects exhibited:
first, there were thrown upon the screen, from photo-micrographic

* “On the Practical Application of Photography to the Microscope.” By
Prof. O. N. Rood. Vol. xxxii., p. 186, ‘Am. Journal of Science and Arts.’

+ “ Astronomical Photography.” By Lewis M. Rutherfurd. ‘Am. Jour.
Sci. and Arts,’ xxxix., 304.

Monthly Microscopical] PROGRESS OF MICROSCOPICAL SCIENCE. 167

slides placed in a oxyhydrogen lantern, seven representations of —
The Navicuta AncuLatum, the original object being +1, long, and
marked by 52,000 striz to the inch. ‘These were photographed upon
the lantern slides, magnified as follows: 12, 118, 370, 1562, 2344,
9525, and 19,050 diameters, which gave a series of pictures upon the
screen, the linear diameters of which were forty times the above, or,
480, 4720, 14,800, 62,480, 93,760, 381,000, and 762,000; the latter
being in superficial measurement, 762,000 x 762,000, which equals
the enormous size of 580,644 millions of times that of the original.
These were particularly interesting, since they exhibited the varied
appearance of the object when under the different powers, passing from
what appear to be two sets of oblique parallel lines crossing each
other, to hexagonal, and finally, under the last to circular markings ;*
which, however, on moving some distance from the screen, seemed to
again change into hexagons. The Popura Piumspea Scate was the
next object. The insect from which this test object is obtained is
from the 5!, to the ,4, of an inch in length, and the scale represented
in these photographs is the 51, of an inch long, each spike upon this
being about z255 of an inch in length. Three specimens were shown,
which were magnified 522, 756, and 2100 diameters, giving on the
screen 20,800, 30,240, and 84,000 linear diameters; these gave most
_ satisfactory representations of the spikes, which seemed to be so clear
and well defined as to leave but little doubt as to their shape and
structure. The Pievrosiama Formosum, jth of an inch in length,
and having 36,000 striz to the inch, was x 640 and 2540, or 25,600,
and 101,600 diameters upon the screen, Finally, to conclude the
series, the TEsT PLATE OF Nosert—which is regarded as the most
accurate means of determining defining power—had been photo-
graphed, and the slides were brought for exhibition. This optician
has issued these plates with lines gradually increasing in fineness ;
and his latest works have exceeded any of the former in this respect.
The first test plate had ten bands, which were ruled at the rates of
4431964 lines to the millimeter. The second plate, prepared in
1849, had twelve bands; the third plate had fifteen bands, the last
one of which was ruled at the rate of 2216 lines to the millimeter.
The plates of 1852 had twenty bands, the finest being 2664 to the
millimeter ; this was described by Mr. Richard Beck, who, with a th
and No. 3 eye-piece x 1300, found thirty-five lines, each about
azodos th of an English inch apart. Nobert next prepared a thirty-
band test. plate, the thirtieth band of which had 3544 lines to the milli-
meter. This was the plate described by Sullivant and Wormley.t The
last plates made by Nobert have nineteen bands, the 15th corresponding
to the lines of the 20th band of the 30-band plate, and the 19th ruled
at the rate of 4430 lines to the millimeter. Dr. Woodward gave a
somewhat extended description of his investigations in this direction,
for an account of which the reader is referred to his paper in the

* “On the Evidence furnished by Photography as to the Nature of the
Markings on the Pleurosigma Angulatum.” By Prof. O. N. Rood, ‘Am. Journal
of Science and Arts,’ vol. xxxii., p. 335.

_ + ‘American Journal of Science and Arts,’ January, 1861.

168 PROGRESS OF MICROSCOPICAL SCIENCE. [Monthly Mictoscon

‘London Microscopical Journal’ for 1868. At the time he published
that article no microscopist had succeeded in seeing the true lines in
any of the bands in this plate beyond the 15th. This spring, how-
ever, with a Powell and Lealand immersion +},th, he had resolved the
four higher bands, and now showed photographs of them. These
bands presented the following number of lines,—the 16th 48, the
17th 51, the 18th 54, and the 19th 57, each in about 5,1,,th of an
inch. Papers announcing this success had been sent to the ‘ MonTHLY
Microscopical JouRNAL’ and to ‘ Silliman’s Journal.’ A number of
anatomical objects was also exhibited.

The Origin of the Gall-ducts——Dr. R. Cresson Stiles, of New York,
has been studying the livers of cattle which have died of hepatic
disease in which the bile-ducts became charged with biliary matter,
and he believes that his researches have led him to accurate conclu-
sions as to the mode of termination of these canals. He thinks he
has proved the existence of minute terminal reticulations, and states
that he has demonstrated them to the New York Academy of Medicine.
He writes as follows to one of the New York medical journals :—
‘* Let it be understood that I have nowhere claimed to have made a
‘discovery,’ but simply to have made certain what others believed
they had demonstrated, although their opinions have not received the
support of the highest authorities in histology. The following
passage, from Kolliker’s ‘Handbuch der Gewebelehre,’ will show pre-
cisely what I have seen and demonstrated before the New -York
Academy of Medicine, and to a large number of skilled histologists :
— The teachings of Budge and Schmidt are entirely different, which
are, that they believe they have demonstrated, by means of injection,
in the interior of the acini, between the liver cells, the finest gall-
ducts. According to Budge, the gall-ducts suddenly contract at the
surface of the acinus to ‘002’, and fine canals of this calibre extend in
the form of a network between the liver-cells throughout the acinus.
Schmidt's confused statements may be seen in his work, which,
however, is endorsed by another worker, to the effect that he has
injected from the gall-ducts a network of fine canals of the :0013
of a millimétre to the ‘0014 mm. which pervades the entire acinus,
and in such wise that the canals never run by the side of the blood-
vessels, but only between the cells of the liver. All these canals are
perfectly cylindrical, and apparently of the same thickness, yet a
membrana propria cannot be demonstrated.’ Kolliker regards these
canals (as he has not seen the preparations of the histologists whose
opinion he combats) as formed by the escape of the injecting material.
My own observations on the gall-ducts injected by the tenacious bile
peculiar to the Texas cattle disease, prove that this explanation is in-
admissible. Kolliker says, furthermore, ‘ Reichert and Henle have
thought of lymphatics. ‘The tenuity of the canals in question would
not invalidate this opinion, as Henle believes, for the larve of frogs
have just as fine lymphatics with walls; but the presence of - fine
canals in the interior of the framework of liver-cells, as far as I under-
stand the development of the liver, makes this opinion entirely
untenable. Should this network be one of lymphatics, it is one of

Monthly Microscopical] NOTES AND MEMORANDA. 169

lymphatics which empty into the gall-ducts between the acini, into
which I have distinctly traced them.”

The Leaves of Conifere.—Mr. Thomas Meehan has laid a short
memoir on thig subject before the “ American Association for the
Advancement of Science,” and which wiil appear in the forthcoming
volume of the ‘ Transactions.’ He analyzes the opinions of Drs. Dick-
son and Engelman, and having described some of his observations on
the relation of the old fasicles to the woody system of the tree, he
concludey:—(1) That the true leaves of Conifer are usually adnate
with the branches. (2) Adnation is in proportion to vigour in the
genus, species, or in the individuals of the same species or branches of
the same individual. (8) Many so-called distinct species of coniferse
are the same, but in various states of “adnation.”

The Structure of Brunner’s Glands—A memoir on the anatomy
of these intestinal glands was read before the Vienna Academy of
Sciences, at its last meeting for the present session (July 15). It
was written by Herr Anton Schlemmer, of the Physiological Institute
of the Vienna University. The author alleges that these glands are
not racemose, as generally asserted, but are tubular. The memoir is
not yet published in full.

The Distribution of the Tracheal Vessels in Ferns.—M. A. Trécul
has published some of the results of his researches in a very long
communication to the ‘Comptes Rendus,’ of July 26th. The author
refers to the great difficulty of explaining his observations without
figures. It would then be impossible for us in a few lines to give
any adequate idea of the author’s views. We may mention that he
goes minutely into the investigation of the vascular system of ferns,
and describes the arrangement of the tracheal vessels in from twenty
to thirty different species.

A New Hermaphroditic Borlasia—M. A. F. Marion has discovered
on the coast of Marseilles a new species of Borlasia, which, like the
B. hermaphroditica of Professor Keferstein, is monecious, He calls
it B. Kefersteinit, and describes its reproductive apparatus. It
measures 15™" in length, and is covered with vibritile cilia. Both
male and female “ovules,” as the discoverer calls them, are developed
between the hepatic layer of the digestive tube and the walls of the
body. The female ovule measures -317™™, the males are smaller,
and are filled with zoosperms.

NOTES AND MEMORANDA.

Parallel-rays Condensing Iluminator.—Dr. Royston Pigott sends
us a sketch and account of an instrument devised by him, and to which
he has given the above name. The instrument was constructed for
him by Messrs. Powell and Lealand, and “with it a very intense set —

YOR. ii; N

170 NOTES AND MEMORANDA. Meee were

of parallel rays can be thrown upon the object at any required degree
of obliquity.” He found the Podura beads were shown with it very
satisfactorily, ahd he states that “it has the advantage of regulating
obliquity to a great nicety, and giving a pencil of rays producing in
some cases a fine definition.” The illuminator itself consists of
three plano-convex lenses, one of which, that on which the light falls,
is of 2-inch focus, and the two others of which have respectively a
1-inch and a 3-inch focus. The large and the small lens are adjust-
able by means of a sliding cap. The movements of the illuminator
(which can be effected with any degree of obliquity) are provided for
by a graduated arc, which fits beneath the stage of the microscope, and
on which the illuminator works.

A suggested Plan for Dark-ground and Oblique Ilumination.—
A correspondent gives the following brief description of a method
employed for the above purpose :—Let a square be cut parallel to the
base from a square or hexagonal pyramid of glass, grind and polish
its edges to four or six different angles to suit various object-glasses.
Drill a hole through its centre, and mount with slotted diaphragm
to fit substage. The prism thus formed may be plain or tinted glass,
any edge may be achromatized by a small flint prism or cylindrical
lens of requisite curve cemented to its under-surface. ‘The bull’s-eye
condenser, and stage-mirror are used for illumination. A flat line of
light is thrown obliquely upon the object, well adapted to bring out
markings on tests. Cylindrical lenses might also be employed for
the same purpose.

Prizes for Collections.—The Committee of the Belfast Naturalists’
Field Club offer a number of prizes for the best collections of various
Natural History objects, Some of the prizes are valuable. The one
devoted to microscopy is not large, but it may eventually develop
into something better. It is a prize of 10s. for the best set of twenty-
five microscopical slides. Prizes to be competed for in March, 1870.

Messrs. Cassell’s Estimate of Microscopic Perfection.— Messrs.
Cassell announce the fact that, in accordance with a want expressed
by readers of their ‘ Popular Educator,’ they “ have arranged to supply
through the ordinary trade channels, at exceptionally low prices, a
series of first-class microscopes, many of them designed on new and
improved principles, for school use and private study” (‘ Echo,’
Aug. 11th). The following is a description of these first-class instru-
ments (!) :—‘ The Society of Arts’ Prize School Microscope, with rack
adjustment, 3 powers, giving 656 superficies, with condenser, ani-
malcule-cage, pliers, &., 10s. 6d. Ditto, with body and eye piece, con-
verting it into a compound microscope, 13s. Superior School Micro-
scope, with joint, achromatic, magnifying powers 400 to 8000 times,
in neat mahogany cabinet, 21s. Achromatic Microscope, all brass,
3 powers, magnifying 50, 100, or 180 times, in mahogany cabinet,
38s. Achromatic Microscope, on bronze stand, very powerful, 45s.
Ditto, ditto, larger, 50s. Compound Achromatic Microscope, on
bronze stand, to incline at any angle, with rack-work adjustment,
stage, and diaphragms, 63s.” Those who know anything of micro-

aE cece CORRESPONDENCE. 171
scopes will form their own opinion as to the working capacities of
these microscopes, the best and most expensive of which actually pos-
sesses “a stage and diaphragms” (!); but the “masses” to whom the
advertisement is addressed will, according to custom, take omne ignotum
pro magnifico. Itis quite clear that Messrs. Cassell wish to do good,
but that they have not gone the right way about it. Ona point of this
kind they should have sought the aid of the Royal Microscopical Society,
whose Council and officers would have put them in a better position
to help scientific education.

The Histology of the Eye is the subject of some recent lectures
of Mr. J. W. Hulke, to which we would direct attention. We hope
in an early number to give an abstract and illustration of the results
of Mr. Hulke’s researches.

Immersion Objectives.—In answer to our correspondent, Mr. J.
Newton, of Liverpool, we beg tq@esay that the subject is receiving
great attention from some of our best workers. The matter is still
sub judice; but we think we may anticipate the final decision by
stating that, if only from their cheapness, the immersion lenses are
likely to become very popular in this country. The best glasses
are those made by Merz, of Munich, and Hartnack, of Paris. An
advertisement of prices of the lenses of the former appeared in an
early number of this Journal.

Microscopy in the Peabody Academy.—We have received the
first annual report of the Academy of Science founded by Mr. Peabody.
We regret to notice that while other departments of physical and
natural knowledge have been carefully attended to, there is no mention
whatever of a section of microscopy, nor does there seem to be any
provision in the new museum for the teaching of histology.

Micro-photographs.— Under the auspices of the Royal Academy
of Vienna, M. Martin has been making a series of photographs of
microscopic objects. He employed eye-pieces and objectives by Mr.
Ladd, of Beak Street, and by Hartnack, of Paris.

CORRESPONDENCE.

THE New Untversat Dissecrinc Microscope.
To the Editor of the ‘ Monthly Microscopical Journal,’
JERSEY, July 1Ldth,

Sir,—The June number of your Journal contains an account
by Mr. W. P. Marshall, President of the Birmingham Natural History
and Microscopical Society, of a “new universal mounting and dis-
secting microscope,” which he says has been ably worked out and im-
proved from his designs by Messrs. Field, of Birmingham. There is
a slight error as to the origin of those designs which I should feel

obliged by your allowing me to correct.
N 2

172 CORRESPONDECE. "Fournal, Sept. 1, 1869.

The real origin of the instrument is as follows :—Several micro-
scopes for dissecting purposes had been exhibited at our meetings,
among others that by Messrs. Smith and Beck. Mr. Marshall after-
wards suggested that this might be made more useful by certain modi-
fications embodied in a model which he exhibited and explained, and
in which the apparatus was stowed away under the stage, and the case
was a square box slipped on from above, like a hood.

The awkward part of this was that it was necessary to remove the
apparatus from below the stage before beginning to work. It struck
me that if, instead of the case being a square hood, it were made to
open (by hinges) away from the stage, the apparatus could all be
attached to the case, instead of encumbering the instrument. I made
and exhibited at the Birmingham Natural History and Microscopical
Society a model (which I have with me now in Jersey), from which
most of the ideas appear to have been gleaned for the making of Mr.
Marshall’s microscope. +

May I trespass on your kindness so far as to give a few words of
description of my instrument, touching on some of the points of simi-
larity and difference between the two?

In order to use my microscope I place the box on the table, with
the lock towards me, lift up the lid and throw it back, open back the
two sides (which with the lid are hinged to the back), when the case
may be pushed away to a convenient distance, and the instrument is
ready for use. The turn-table, hot-plate, &c., are attached to the case,
and not to the stage, so that I can examine an object, transfer it to the
hot-plate, and then varnish it on the turn-table without loss of time in
fixing and unfixing.

This is a decided advantage, as if I am mounting a large number
of objects I do not have to turn away the microscope arm, move the
mirror, and change the stage-plate for the hot-plate, and vice versa,
with each individual object, and my turn-table working on the case
instead of the stage, I do not have to strain the microscope arm by
using it “as a convenient support for the hand when making cement
rings.”

My model was fitted to receive a compound body, but had not the
arrangement for inclining the stand when used as a compound micro-
scope.

apes the apparatus I had a wash-bottle, hot-water bath, small
benzoline lamp with mirror and condenser, stage forceps, zoophyte
trough, animalcule cage, and several other things, in addition to most
of those contained in Mr. Marshall’s. These, of course, are, however,
mere matters of detail; the part which I claim as being my sole idea
is the attachment of the entire stock of apparatus to the case, and the
hinging together of this case in such a manner as to allow of the case
and microscope being separated and brought into use in an instant.
The size when packed is nearly a 7-inch cube.

My model was in the hands of one of the London makers at the
time Mr. Marshall’s was sent to the Royal Microscopical Society, and
I was totally unaware that any one was working at the matter until,
in May, a friend informed me that Messrs. Field had made up a

wv OUtna, Sepa Leis | + PROCEEDINGS OF SOCIETIES. 173

microscope very much like mine for sale, and were selling it as Mr.
Marshall’s.

With all respect to Mr. Marshall, I think it should have been
brought out in our joint names, or, at least, I should have been
written to before the microscopes were brought before the public.

Cuartes Apcock, M.R.CS., &e.,

Corresponding Member (late Hon. Sec.) Birmingham Natural History and
Microscopical Society ; Resident Medical Offieer, Jersey Dispensary.

PROCEEDINGS OF SOCIETIES.*

OxtpHAM Microscopic Socrery.t

July 138th—The Chairman, Mr. Pullinger, in opening the pro-
ceedings, briefly reviewed the history of the Society, congratulating
the members on their increased numerical strength, and the many
valuable additions they had made to their stock of working micro-
scopic apparatus during the four years of the Society’s existence.

Mr. Waddington read a paper “On our British Mosses,” in which
he discussed their beauty as microscopic objects, the pleasures and
advantages to be derived from their study, their geographical distri-
bution, their economic value, and the part they had probably played
in past geologic ages.

It was a pleasure to him, he said, to live at a time when these
beautiful objects could be examined and studied with the help of —
instruments so much superior to those with which the great Linnzus
conducted his investigations. Many important corrections and many
new discoveries in muscology had been made with our improved
means, which were utterly impossible with the old and imperfect
instruments. The simple structure of mosses correctly placed them
low in the scale of vegetable being. On the one hand, the andriews and
phascums connected them with the more lowly Jungermannias ; and,
on the other, the sphagnums, with their more complex organization,
clearly conducted to the higher cryptogams, thus offering, he thought,
a few of the “links” so much clamoured for by the opponents of the
development theory. The paper was well illustrated by numerous
slides of sections of mosses, many of them contributed by the members
generaliy, all bearing on the points adverted to.

The paper concluded with a lucid explanation of the best modes

of mounting and preparing for the microscope the different parts of
mosses.

_ _* Secretaries of Societies will greatly oblige us by writing out their reports
legibly—especially the technical terms—and by “underlining” words, such as
specific names, which must be printed in italics. They will thus ensure accuracy
and enhance the value of their proceedings.—Ep. M. M. J.

+ Report supplied by Mr. James Nield.

Ee Microscopical

174 PROCEEDINGS OF SOCIETIES. Journal Sept. 1, 1869,

Microscopic Section oF Mancuester Lower Mosrry Street
Naturat History Society.”

Report of meeting, 15th July, Mr. Chaffers, President, in the chair.
Mr. Hyde read a paper “On Pollen and its Functions.”

The reproductive organs were mentioned, and their sexual differ-
ences noted. The growth of the anther, its internal arrangement for
the formation of the pollen, having been described, the pollen grains
were next considered. They are formed from a substance called
cellulose, in the cells of the anther, the principal cells dividing so as
to form an independent cell. ‘They consist of various substances, as
gum, starch, resin, pollinine, &c. Fovilla is a very minute granular
matter which is contained in pollen grains. The pollen tube down
which the fovilla passes is formed of the intine of the granules.

The various markings and grooves on the surface of pollen were
described, and a large number of specimens were shown to exhibit
them, including Liliwm auratum, Coboea scandens, Amaryllis vittata,
Amaryllis formossissima, Polyanthus narcissus, the Cotton plant, and
about twenty others.

Mr. Armstrong contributed two microscopic objects, Batracho-
spermum moniliforme and the Pond-skimmer, to the Society’s cabinet.

Mr. Jackson promised to read a paper upon ‘‘ Seeds as Micro-
scopic Objects,” at the next meeting, 2nd August.

Mr. Jackson was elected Hon. Secretary, in the place of Mr.
Wilmot, resigned, through leaving Manchester.

MancHEsteR CrrcuLatTina Microscopic Caprnet Socrery.t

Quarterly meeting, held 27th July, 1869, Mr. Horne, President,
in the chair.

Mr. Hope read a paper “On the Structure of Ferns,” after which
the members present exhibited the various slides they had prepared,
since last meeting, illustrating that subject.

Mr. Aylward proposed the following resolution, which was se-
conded by Mr. Armstrong, and carried unanimously: “That during
the coming winter session (from October to April), the members of
this Society shall study the structure and classification of ‘ Foramini-
fera,’ and that meetings shall be held monthly during that term, so
as to allow the members an opportunity of comparing and exchanging
their slides, and of general discussion on the subject.”

Resolved that the subject for examination at the next quarterly
meeting shall be “ Foraminifera.” Hach member will be expected to
bring slides illustrative of that class of objects, and is requested
to bring any sand he may have to spare for distribution amongst the
members.

BRIGHTON AND Sussex Naturat History Society.

August 12th.—The President, Mr. Glaisyer, in the chair. A
paper was read by Mr. T. W. Wonfor, “On certain Facts in the Life-
History of Moths and Butterflies.” In rearing Lepidoptera, for the

* Report supplied by Mr. Thomas Armstrong.
+ Report furnished by the Hon. Secretary.

eeseaa eepe kes. PROCEEDINGS OF SOCIETIES. 175

purpose of determining the possession of a distinctive scale by the
males, several facts, some well known, others opposed to generally-
received opinions, and others perhaps of a novel character, had forced
themselves upon his notice. As was well known, the Lepidoptera in pass-
ing from the egg to the mature state, underwent the several changes of
larva, pupa, and imago. In two, and in some cases in only one of these,
did the insect partake of food. For while all were voracious in the
larval state, and while many possessed a proboscis of great length,
other species did not possess any suctorial apparatus, and therefore
could not take food. The parent, as a rule, laid the eggs on or near
the food-substance of the larve, the gradual development of which, in
many transparent eggs, can be watched under the microscope. While
the changes are taking place the colour of the egg also changes. As
soon as the larva is ready to escape, it eats its way seldom at the
apex or micropyle, where some writers assert it always escapes, but
generally below and at one side. The eggs of many are very beautiful
objects for the microscope. The larve of various, and some of pecu-
liar forms and habits spend their time in eating and changing their
skins. In fact, the chief aim of their existence, at this stage, is
storing up vitality to enable them to undergo their further changes ;
for when supplied with insufficient food, or alternately starved and
fed, the imago stage is either not reached, or a mutilated or deformed
insect results. When the time arrives for the change to the proper
state, some construct elaborate cocoons, others suspend themselves
from twigs, &c., others burrow, all casting the last larval coat, when
they become chrysalides. Just before the final change, the colour
of the chrysalis alters, and through the pupa-case the several parts of
the future insect may be made out. At last the pupa-case bursts,
and the fully-fledged insect emerges, with wings of minute size; these
expand as air and fluid are forced through them. The scales at the
time of emerging are all of full size. This is an important fact, for
some assert that the scales expand together with the wing membrane
itself, the air breathed-in, entering between the lamine of each scale ;
others maintain that the scales are small and few in number in newly-
developed insects, but larger and more numerous as the insect advances
in age. Both these theories are contrary to fact. If either that
portion of the pupa-case which covers the wings be removed a few
days before an insect emerges, or the wing of a newly-emerged insect
be taken, it will be seen that the scales are all of full size, but closely
packed together longitudinally and laterally. As the wing membrane
expands they are drawn wider and farther apart, until they present
the appearance seen on a fully-expanded wing. Experiments made
with the Puss moth and Oak egeur, to determine in the first case by
what means the insect dissolved its hard cocoon, and in the second
to find how the males were attracted, were next described. Several
cases of parthenogenesis, in which none of the larve reached the third
noult, and examples of a second copulation, were next mentioned.
The females possessed greater vitality than the males, and made, in
articulo mortis, efforts to lay their eggs, which in some cases for days
after death were extruded. While such varied colours were seen in
Lepidoptera, the scales themselves, when viewed by transmitted light

176 BIBLIOGRAPHY. L ‘Sournal, Sept-1, 1865.
were either colourless or of a dull yellowish tint. As regarded a
distinctive scale on the males, there was not a doubt that in many
families the males possessed scales of a peculiar type, known as the
“pattledore” or “tasselled” seale; further researches might reveal
other types. It could very safely be laid down that no female pos-
sessed a battledore or tasselled scale, hence wherever found they were
indicative of sex. Several other points were advanced, and the life-
history of different moths and butterflies described. The paper was
illustrated by a collection of insects in the several stages, and by
microscopic preparations.

It was resolved that a letter of invitation from the Society to the
British Association, requesting the honour of a visit to Brighton, be
forwarded through Mr. Mayall, who had consented to represent the
Society at Hxeter.

BIBLIOGRAPHY.

Etude sur l’Anatomie comparée de l’encephale des poissons; par
M. le docteur Baudelot, Professeur de Zoologie a la fuculté des
Sciences de Strasbourg. Strasbourg. Silbermann.

Note sur l’Anatomie des deux espéces du genre Pericheta et essai
de classification des annélides lumbricines; par M. Léon Vaillant.
Ato, 3lpp. Montpelier. Boehm et fils.

Zur Entwickelungs-geschichte de Siphonophoren. Beobachtungen
tieber die Entwickelungs-geschichte der Genera: Physophora, Crystal-
lodes, Athorybia; und Refiexionen tieber die Entwickelungs-geschichte
der Siphonophoren im Allgemeinen von Dr. Ernst Haeckel. Utrecht.
Vander Post.

| Handbuch der Lehre von den Geweben des Menschen und der
Thiere. Herausgegeben von Herrn S. Stricker. 2 Lieferung. Leip-
zig. HKngelmann.

Bulletin de VAcadémie Impériale de St-Pétersbourg. TT. xiv.
Leipzig. Voss.

Ueber Bliitentwicklung bei den Compositen von Herrn Em
Koehne. Berlin. Enslin.

Zur Anatomie von Prurigo von Dr. R. H. Derby. Wien. Gerold’s
Sohn.

Bericht tieber die wissenschaftlichen Leistungen in der Natur-
geschichte der niederen Thiere wahrend der Jahre 1866 und 1867,
von Prof. Rudolph Leuckart. Berlin. Nicolai.

Vorlaufige Notez tieber den Ursprung und die Vermehrung der
Bacterien von Dr. A. Polotebnow. Wien. Gerold’s Sohn.

The Monthly Microscopical Journal Oct" 1 136

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THE

MONTHLY MICROSCOPICAL JOURNAL.

OCTOBER 1, 1869.

I.—On the Structure of the Stems of the Arborescent Lyco-
podiaceze of the Coal Measures. By W. Carrutusrs, F.L.S.,
F.G.8., Botanical Department, British Museum.

(“ Taken as Read” before the Roya Microscopicat Society, June 9, 1869.)
(Communicated by the President.)
Piatt XXVIII.

Havine for some time been collecting materials for the illustration
of the stems of Stgillaria, Lepidodendron, and other forms of
gigantic Lycopodiacee belonging to the Carboniferous period, I
propose to submit to the Society some account of these remarkable
structures, and to examine the points of agreement and difference
between them and the stems of existing plants.

I have been especially fortunate in obtaining a large collection of
fossils from the beds of volcanic ash discovered by E. Wunsch, Esq.,
in the north-east corner of the Island of Arran, in the Frith of
Clyde. Guided by his son, I had myself the pleasure of exploring
the beds and of collecting a number of specimens. The rocks are
exposed on the shore at Laggan, and consist of a considerable series
of volcanic tufas indurated by infiltrated carbonate of lime, alter-
nating with thin beds of hardened shales. Stigmarian roots abound
in the shales, and, with not a little difficulty, I removed the super-
imposed rock and traced the radiating branches of Stzgmarza pro-
ceeding from a large trunk of Sigillaria. The different beds of

EXPLANATION OF PLATE.

Fig. 1.—Transverse section of a portion of the stem of Lepidodendron selaginoides,
Sternb., from the centre to the circumference. a. the axis. 0. the
investing cylinder, both composed of scalariform vessels. c. delicate
parenchyma, more or less decayed. d. stronger parenchyma passing
into prosenchyma e. f. outer layer of the prosenchyma. g. the bark,
h. section through the decurrent base of a leaf.

9, 2—Longitudinal section of ditto through the centre of the axis. The letters
refer to the same structures as in Fig. 1. The open space above the
letter c arises from the decay of the delicate parenchyma; that above
the letter d, which passes upwards and outwards, was occupied by a
vascular bundle and its associated delicate parenchyma.

», 3.—One of the cellular rays in transverse section.

» 4.—Section of several rays at right angles to their direction.

VOL. II. O

178 Transactions of the Pe aeons aig
shale formed the soil on which grew extensive cryptogamic forests,
that were successively destroyed when in their prime by showers of
voleanic ash, which broke down and buried in its mass the branches,
and left as bare poles the scorched and dead stems rising high
above the ash as witnesses of the terrible destruction. In the
course of time they were hidden by the growth of a luxuriant vege-
tation which speedily covered the new soil, but only to be destroyed
by a fresh outburst from the intermittently active volcano in their
neighbourhood. Frequently spores found a suitable nidus in the
decayed and hollow interior of these immense stems. Mr. Wunsch
has given me specimens, in which from six to nine young trees,
with stems from two to three mches in diameter, belonging pro-
bably to several distinct species and at least to two genera, have
erown by the side of each other within a single trunk. The frag-
ments of the branches in the beds of tufa retain to a great extent
their original form, and the minute structure is often preserved in
a singularly perfect manner. In addition to the specimens I myself
collected, I have been supplied in the most liberal manner by
Mr. Wunsch with specimens collected by himself. I am also
indebted to Mr. J. Young, of the Hunterian Museum, Glasgow,
for some interesting specimens he obtained from the same locality.
Professor Morris has supplied me with several important speci-
mens from the Lancashire coal-field. The grant placed at my
disposal by the British Association has enabled me to have these
various materials prepared by the lapidary, so as to be able to
make the most exact microscopical examination of their structure.
In addition to these, I have had the use of several fine preparations
from the cabinet of Dr. J. Millar; I have examined the valuable
Series of microscopic preparations recently acquired by the British
Museum, made by Nicol (the inventor of the method of slicing
fossils) and Bryson, and the yet more valuable collection made by
Robert Brown, and bequeathed by him to the same institution.
The specimens exhibiting structure are generally in nodules in
the coal. The conditions which were favourable to the accumula-
tion and preservation of the plant-remains of the Coal period in a
state of purity that makes them now invaluable to man, did not
also favour the conservation of those characters which would enable
us to determine the nature of the plants themselves. With the -
exception of the thin layers of charcoal, commonly called “ Mother-
coal,” the origin of which has never been satisfactorily accounted
for, the whole mass of vegetable matter was speedily reduced to a
homogeneous and amorphous condition by decay, greatly assisted
by the abundant water. The covering of plastic clay, now mdu-
rated into the shale, which invariably forms the “roof” of every
good seam of coal, stopped the progress of decomposition, and
sealed up the precious deposit against the intrusion of injurious
substances like iron or lime. It is only where this cover has been

Pe bet ae Royal Microscopical Society. 179

insufficient to isolate the bed or has had in itself iron or lime, some
of which it has parted with, that nodules are found in the coal,
making the seam where they occur in quantity of less economic
value, but supplying to the naturalist the means to some extent of
reading the life history of that period. By the mysterious power
of selection and accretion which has formed nodules in sedimentary
rocks, fragments of the tissue of the bed have been arrested in their
decay, and converted into imperishable limestone. It is seldom that
the preserving material has had access to the structures in time to
preserve them in their entirety. ‘The more delicate cellular tissue has
generally been completely lost. The Arran specimens are remark-
able exceptions to this state of things, and this is probably owing
to the conditions under which they were buried. ‘The hot ashes,
which formed their tomb, appear to have completely charred them,
and then, converted into charcoal, they resisted decay and pressure
until every cell and cavity was filled by the infiltrated carbonate of
lime which converted the loose ashes into a compact stone, and
at the same time made permanent in its original form all the most
delicate structure of the plant.

The specimen I select first for description is one from the
cabinet of Dr. Millar, belonging to the type described by Mr. Binney
under the name S2gillaria vascularis.* As the specimen belongs to
Lepidodendron selaginoides, Sternb., I shall employ, in accordance
with the invariable practice of naturalists, the older name in speak-
ing of it. I have chosen this species because it is one that may
easily be obtained by students. I have it from different localities,
and Mr. Binney tells us that the Halifax Hard Seam or Ganister
coal at South Ouram, near Halifax, contains im some places so
many of the nodules as to render it useless—that they occur over
a space of several acres, then almost disappear, but occur again as
numerous as before,—and that this has been traced over a distance
of twenty-five to thirty miles.

As the technical terms which I shall be obliged to use for per-
spicuity are somewhat different from those employed by Mr. Binney,
there is the more necessity for redescribing this fossil; besides, I
shall add some points which I have determined in my examination
of the series of specimens which have passed through my hands.

The stem of the Lepidodendron selaginoides, portions of which
I have figured on the Plate, is somewhat compressed, being 1 inch
across its greater diameter and ? of an inch across its lesser.

The axis of the stem is composed of scalariform vessels of large
diameter. In transverse section (Fig. 1a) it is seen to be composed
of two parts—Ist, a central portion, consisting of vessels of different

* “On some Fossil Plants showing Structure, from the Lower Coal-measures
of Lancashire,’ by E. W. Binney, Esq., F.R.S. ‘ Quart. Journ. Geol. Soc.,’ vol.
Xvill., p. 106, Pl. IV. and V. The stems described under the same name in the
‘Phil. Trans.” by Mr. Binney, are different, and are consequently not taken into
account in the present notice,

0 2

180 Transactions of the [yaaeneLiocr = aes

sizes, more or less circular or polyhedral in section, and arranged in
irregular order; and 2nd, an external portion, in which the vessels
have an irregularly radiating direction, their longest diameter being
in the line of the radius (this is not well rendered in the plate). The
circumference of the axis is regular, from the interspaces between
the large vessels being filled in by some of smaller diameter. The
vessels are of considerable length (Fig. 2a), so that I have not been
able to obtain a longitudinal section which would show with certainty
both terminations of one. Some of those in the centre of the axis
are divided into chambers by horizontal septa, or rather they appear
to be made up of a series of short obtuse cells, whose transverse as
well as longitudinal sides are marked with scalariform bars. Such
interrupted vessels are scattered irregularly through the others. I
can detect no trace of any other structure in the axis than scalariform
vessels. |

Surrounding the axis is a narrow cylinder of radiating scalari-
form tissue (Fig. 16), differing from that of the axis only in the
method of its arrangement, and in the smaller diameter of the
vessels. They are seldom more than a quarter of the size of those
of the axis, and are smallest at their origin in the interior of the
cylinder. Their form in transverse section 1s sub-quadrangular.
They are separated into groups of one, two, three, or four rays by
a horizontal radiating structure composed of somewhat elongated
cells with truncate ends, and delicate walls without any markings
on them (Fig. 3). The cells are from two to four times longer
than the diameter of the scalariform vessels of the cylinder, while
their transverse diameter is only half that of their vessels. Ina
longitudinal section at right angles to the radius these cells are seen
to be arranged either singly, in longer or shorter linear series, or
occasionally in larger wedges composed of two or three cells in thick-
ness (Fig. 4). In addition to this cellular structure there also are
seen passing outwards, between meshes in the cylinder of scalari-
form vessels, bundles of similar but more delicate vessels connected
with the leaves. Both these structures are described by M. Bron-
eniart in his Sigillaria elegans. The first are his medullary rays.
It is obvious that this term is scarcely admissible here, as the axis
of the stem is not occupied with a cellular or medullary tissue,
but with scalariform vessels. In a recent paper on Sigilaria* I
ventured to doubt that these were medullary rays, but I was not
then able to show that whatever the structure is it cannot be inter-
preted as similar to that of the medullary system of dicotyledons.

The vascular cylinder is surrounded by a considerable thickness -
of delicate parenchyma (Figs. 1¢ and 2c), which in most specimens
has completely disappeared, but in that figured some remains of it
exist in the transverse section near the vascular cylinder, and a -
larger quantity is seen in the longitudinal section (Fig. 2c). The

* “Quart. Journ. Geol. Soc.,’ vol. xxv., p. 248.

sournaL Ost fea | Royal Microscopical Society. 181

cells of this layer are small and spherical, with very delicate walls.
They were the first portion of the stem structures to decay, and
almost invariably the cellular rootlets from Stigmarioid and other
roots pushed their way into these decaying cavities, and being there
preserved have been mistaken by several observers for portions of
the tissues of the stem. ‘The vascular bundles, described as pene-
trating the vascular cylinder, pass in an upward and then in an
outward and upward direction through this layer of parenchyma.
Frequently these delicate bundles have been involved in the decay
which destroyed the mass of the cells through which they passed,
and no record of them remains from their leaving the vascular
cylinder until they enter the outer cylinder of more compact tissue.
In the specimen figured I have counted twenty-four vascular bun-
dles, either closely adpressed to or adjoining the vascular cylinder.

The next structure in the stem is a layer of larger and thicker
walled parenchyma (Figs. 1d and 2d), which, by a gradual length-
ening of the cells, and a decrease in their diameter, becomes changed
into the regularly arranged prosenchyma of the circumference
(Figs. le and 2e). These outer cells agree in every respect with
true wood cells, being greatly elongated and having pointed extre-
mities, and the method in which they are arranged is very much that
of the wood cells in exogenous stems. No indication of any hori-
zontal cellular structure has been detected in this prosenchymatous
cylinder corresponding to what has been described in the scalariform
tissue. The vascular bundles, accompanied with a certain amount of
cellular tissue, pass upwards and outwards through it to the leaves.

In the specimen figured, the outer portion of the prosenchyma
(Fig. 1 f), consisting of six cells in depth, has a slightly different
aspect from the rest, and has been easily detached from it. In posi-
tion, appearance, and the ease with which it separates from the older
structure, it answers to the younger growing portion of the wood in
exogenous stems, and may have had a corresponding significance.

Outside this there is a layer of small thick-walled parenchyma
(Fig. 19), from eight to twelve cells thick, forming the external bark.

The vascular bundles can be traced through all these layers
into the leaf. As they approach the surface of the stem they have
a somewhat circular transverse section. A small quantity of cellu-
-lar tissue occupies the centre of the bundle. It 1s its termination
in the centre of the characteristic scar of this species which gives
the circular depression shown in the figures of the fossil.

The bases of the leaves are persistent, and are composed of
roundish parenchyma (Fig. 1h). The leaves themselves seem to
have been deciduous, for in a specimen where the section passes
through the end of the vascular bundle, the surface of the rhom-
boidal elevation which supported its leaf is cicatrized, being composed
of a layer of small thickened cells.

182 Report on Mineral Veins MoTCOR Le,

II.— Report on Mineral Veins and their Organic Contents in
Carboniferous Limestone. By Cuartes Moors, F.G.S.

At the late meeting of the British Association at Exeter I con-
tributed a paper on the above subject, and as many of the organic
remains to which I then referred belonged to the Microzoa, a short
notice of them, and the peculiar circumstances under which they
were found, may not be uninteresting to the readers of the ‘ Monthly
Microscopical Journal.’ I stated that my attention had for some
time been directed to the altered conditions many of the secondary
rocks presented when they came in contact with the Carboniferous
Limestone of the Mendip Hills, especially when they rested against
their southern side. Throughout the whole of the district I found
that the Carboniferous Limestone, during the secondary epoch had
formed the floor of the sea bottom in the later liassic and Rheetic
periods, that they then became greatly fissured, and received within
their walls the minerals and other inorganic contents with which
they are now filled, together with the organic remains that were
in existence in the seas of the period. ‘These fissures or veins ex-
tended throughout the entire length of the Mendip Hills, for a
distance of thirty-five miles. At Charter House a shaft had’ been
sunk for lead ore to a depth of 270 feet, and at this distance from
the surface I found a deposit of blue clay in the vein, from which I
obtained 120 species of organic remains, about 100 of which, though
obtained from a vein in Carboniferous Limestone, were really as
young as the has.

The Ruizopopa thus found I had previously obtained with
others in stratified beds of the lower lias,* whilst the Entomostraca
appear to be of species hitherto found only in the Carboniferous
Limestone.

FORAMINIFERA. ENTOMOSTRACA.
Cristellaria rotula, Lamk. Bairdia plebeia, Reuss.

Pe costata, D’Orb. » Orevis, Jones and Kirby.
Dentalina communis, D’Orb. Cythere bilobata, Miinst.

3 obliqua, Linn. » fabulina, J. and K.

; obliquestriata, Reuss. » mtermedia, Minst.
Frondicularia striatula, Reuss. » ambigua, Jones, M.S.
Involutina liassica, Jones. » cequalis, Jones, M.S.

™ sp. » spinifera, Jones, M.S.
Marginulina lituus, D’Orb. » Lhraso, Jones, M.S.
Nodosaria raphanistrum, Linn. Kirkbya plicata, J. and K.

me radicula, Linn. Moorea tenuis, Jones, M.S.

5 paucicostata, Reuss.
Planularia Bronni, Roem.

* See “Abnormal Conditions of Secondary Deposits,” &c., ‘Quart. Journ. Geo.
Soc.,’ p. 473. 1867.

Mee, Oc 1, eo in Carboniferous Limestone. 183

With the above were also associated five genera of land and
fresh-water shells.

Extending my observations into North Wales and the north of
England, I again found the same general conditions prevail, and
that, more or less abundantly, the lead veins yielded organic remains,
some of them at great depths.

In the Fallowfield mimes and the Silver-band mines, two very
minute seeds of the Mlemingites gracilis, Carr., were found; and
since then I have discovered that horizontal beds of the coal-
measures are almost wholly composed of them; and I infer that
the Fallowfield mine received its minerals and the other contents of
the veins subsequently to the coal period.

In many of the veins in districts wide apart I discovered many
of those remarkable bodies called Conodonts by Pander. They had
been found by the latter in Silurian beds in Russia, who, consider-
ing them to be the minute teeth of fish, created fifty-six species for
their reception. Several kinds have been found by Dr. Harley in
the Silurian bone-bed of Ludlow, who has suggested that they
belong to Crustacea. They have also lately been noticed by
Professor Owen, in a note, in ‘Siluria,’ p. 544, who also points out
the improbability of their being allied to fish. He thinks the
simpler forms not unlike the pygidum or tail of minute Ento-
mostraca, but that against this view was the fact that no
Entomostraca were found with them; and he then states the
probability of their having been united to the soft perishable
bodies of naked mollusks or annelids. I found a great variety
of curious forms, not only in the lead veins, but also in stratified
beds of Carboniferous Limestone, so that their range in the geo-
logical series has been greatly extended. I stated that though
I might agree with the view of Professor Owen, it was not correct
to say that they were not found with Entomostraca; for though
this might not be the case in Silurian strata, yet in the Carboni-
ferous Limestone the beds in which they were found were some of
them in great part made up of this crustacean. The Conodonts
were usually about a line in length, the simpler ones being not
unlike that of a minute conical fish-tooth. I have about forty
varieties, some of the forms of which are not unlike fish-jaws,
whilst others are almost too eccentric and peculiar for separate
description. , ;

The Hntomostraca, though not individually numerous, were
present in almost every mineral vein I have examined, consisting
of about twenty-nine species, most of which were new. They were
included in the genera Bairdia, Beyrichia, Cythere, Cytherella,
Karkbya, and Moorea, the genus Cythere haying about seventeen
species.

184 Report on Mineral Veins. outa Coe Ieee

Provisional List of Foraminifera and Entomostraca from North of England
Mineral Veins.

FoRAMINIFERA. ENTOMOSTRACA,

Dentalina pauperata, D’Orb. Bairdia plebeia, Reuss.
Fusulina (2), young, sp. » _ curta, McCoy.
Involutina liassica, Jones. Beyrichia, sp.

5 polymorpha, Terquem. Cythere bilobata.

- silicea, Terquem. » pyrula, nov. spec.

“s radiata, NOV. spec. 55 egrescens:

ns sub-rotunda, nov. spec. » munda, nov. spec.

+ lobata, nov. spec. » cegualis, nov. spec.

5 crassa, NOV. spec. » sub-reniformis, nov. spec.

5 incurta, NOV. spec. » Jfabulina, J. and K.

; recta, NOV. Spec. » antiqua, nov. spec.

- cylindrica, nov. spec. 5, Mooret, Jones, nov. spec.

obliqua, nov. spec.

A » cuneolina, J.& K., nov. spec.
Lituola gigantea (?), nov. spec.

» Mutensteriana, J and K., nov.

Textularia sagitata, De France. spec.
Linoporus levis (?), P. and J. » Wardiana, J. & K.,nov. spec.
5 HOV. spec.
nov. spec.

39
Cytherella aspera, Jones, nov. spec.
Leperdita Okent, Minst.

Foraminfera—Very little has hitherto been known of this
beautiful class of Microzoa from the Carboniferous Limestone, and
those I was fortunate enough to obtain from the north of England
lead veins will throw considerable light upon them. This will
especially apply to the genus Involutena, which until lately was
only represented by a single living species, the I. liasseca, Jones ;
but two had since been figured by Terquem, the I. polymorpha and
the I. silicea, from secondary beds. My series not only carries
back the above secondary species to palaeozoic times, but associated
with them are eight others; so that under these peculiar conditions
eleven species of this hitherto little known genus occur. Dentalina
pauperata, D’Orb., a now living species, which has been traced
back through tertiary, liassic, and Permian formations, not only
in this series goes back to the Carboniferous Limestone, but I
have been fortunate enough to discover a single specimen in the
Wenlock shale, an evidence of a delicate microscopic shell having
existed through a long series of ages to the present time. The
Tinoporus levis, P. and J., another recent species, would pro-
bably be included in the list, though it requires more examination ;
added to which would be the recent species Teatularia sagitata,
De France, and also the genus Fusulina. Associated with the
above were some nearly spherical bodies more or less drawn out at
the two poles, as though they had formed portions of a moniliform
test. These were suggested by Mr. H. B. Brady, who had examined
the series, to be the joints of a large Lituola, which he provisionally
named L. gigantea, though the specimens were too limited for a

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BB. Truman, del. Tuffen West, sc. . W. West, imp.

Development OL CVn act) le ee!

eipdenalOCh 1 1503” On the Ovum of the Pike. 185

definite or a detailed description.* or the first time there were
sixteen species of carboniferous limestone Foraminifera unexpectedly
making their appearance in mineral veins, three of which had lived
on to the present day, in addition to the liassic forms previously
enumerated from Charter House.

In addition to the Microzoa mentioned above, I may remark
that from veins and fissures of different ages in the Carboniferous
Limestone I obtained remains of the oldest known Mammalia, the
oldest land and fresh-water mollusca, about 32 species of fish and
eight of reptilia; so that altogether, under these peculiar circum-
stances, I have found about 267 species.

III.— Observations on the Development of the Ovum of the Prke.
By E. B. Truman, M.D.

Puates XXVIII., XXIX., and upper half of XXX.

In the spring of 1866 I was engaged in watching closely the
wonderful and beautiful changes that take place in the egg of the
pike of our rivers, which have for their end the development of an
immovable, transparent gelatine-like ball into the most lively,
active, and voracious pike, the king of our fresh-water pools and
streams. I do not propose to go at any length into the minute
anatomical changes which I witnessed, nor shall I permit myself
more than is quite unavoidable the use of technical language. I
intend here to relate the method of obtaining the supply of eggs, of
keeping them alive, and of watching them ; and in a general way,
the interesting and remarkable sights that are to be seen in a study
of this kind. The circulation of the blood throughout a hundred
little veins and arteries, the beating of the fountain of life from and
to which they pass and return, the growth and formation of the
brain, the eye, the ear, and of the viscera, and many other marvellous
processes may be viewed by any one who possesses a microscope and
a supply of eggs. My purpose is to narrate what I saw, so that
others may look for themselves.

In order to obtain a supply of eggs, the pike of both sexes must

* It is a very interesting fact, that within the last few days a bed of Mountain
Limestone, of considerable extent and thickness, has been found on the estate of
Sir Walter Trevelyan, formed almost entirely of this organism. Whether the
fossil really belongs to ZLituola, or may not yet be another phase of that wonder-
fully polymorphic type /nvolutina, is a point upon which my friend Mr. Brady is
at present engaged.

+ The writer desires to state that this paper was originally written for a
periodical of a popular character. This will account for many details or explana-
tions in the text which will be unnecessary to the scientific reader.

) , Monthly Mic ical
186 Observations on the Development _ [Mgnthty. Microscopica

be taken alive, at a time when they are just ready to deposit their
eggs, or to spawn, as it is called. This time will be known to most
fresh-water fishermen, whether professional or amateurs. Some one
endued with the requisite knowledge of the fish and its habits should
be furnished with instructions to look out for pike, male and female,
in the state alluded to,and when found, they must be caught in the
net, and kept alive in water until they reach the experimenter’s or
observer's hand.

I obtained my supply of eggs from a friend who was studying
the subject of egg development. The pike were netted early in the
month of April, the keeper of the (preserved) ponds having been on
the watch for a few weeks before. The fish were brought to town
and transferred from the fish-can to a tub of cold water. ‘There
were two or three specimens of each sex. On the 14th April, 1866,
at 10 a.m., a well-grown female fish was taken out of the tub and
a wet towel wrapped around her head, with a double purpose—in
the first place to maintain a humid atmosphere in the neighbour-
hood of the gills, so as to keep the respiration process going; in
the second place, to prevent any attempt at biting the operator,
the pike having powerful jaws and sharp teeth, and being by no
means disinclined to resent interference with its liberty. The fish
was then laid on a broad, shallow dish, containing a little water, and
the four fingers of a hand passed along the sides of the animal with
a gentle stroking pressure. By this means, if the fish is ripe, or
ready to spawn, the eggs will be found to pass out quite easily,
without any force, so to speak, being made use of, and as it is pos-
sible to nearly empty the ovary, a great number of eggs is obtained.
When a sufficient number was collected, the fish was returned into
the water, and a male pike was taken. ‘This was treated in the
same way. A very small quantity of the male spawn is sufficient
to fertilize the whole number of eggs obtained from a female fish.
There is sometimes a difficulty at this stage of the proceedings to
get the milt to yield its contents: in such a case the fish may be
cut open, and a small piece of the milt placed in the dish contaming
the eggs, and agitated amongst them for about five minutes. ‘The
fragment should then be carefully removed, as otherwise it will de-
compose, and cause the death of the now fertilized ova.

All that is necessary to do further is to put the eggs into a
suitable receptacle (on the bottom of which they should hie at not
more than two in depth), to pour in a good quantity of fresh, clean,
hard water (from a tap will do), and to cover the vessel with a pane
of glass; this keeps out dirt and dust fallmg upon the eggs—which
adhering to them will interfere with microscopic observation—and
yet allows of the free passage of light. ‘The water will require
changing three or four times a day; this must be done gently,
either by decantation or by a syphon. Fresh water must be added

Piwamn Oct so. of the Ovum of the Pike. 187

also gently. Addled or dead eggs become opaque white, and should
be always removed as soon as seen, as their decomposition will
produce further death amongst their neighbours. The living eggs
are of a pale yellow, and semi-transparent, having the hue and ap-
pearance of gelatine, and apparently quite spherical.

In about five minutes after the eggs were deposited they were
found to cohere very strongly. A layer of them, agitated in water,
was seen to wave up and down like a woven tissue might, without
any break. ‘The occurrence of this cohesion is no doubt a provi-
sion for the secure anchorage of the eggs in their native waters ;
they would adhere to rough stones or gravel in the same way as
they adhere inter se.

I may state in this place that the magnifying power I made
use of during my observations was that afforded by a two-thirds ob-
jective, and the low, or No. 1, eye-piece (Smith and Beck), magnify-
ing about 72 diameters. I used this power as it was the lowest
I had, but an inch objective will be found sufficiently high for
such purposes. Neither is it necessary to purchase a costly micro-
scope; any of the cheaper microscopes of the first London makers
will be found sufficient for those whose avocations do not demand,
as mine did, a more expensive instrument.

In order to watch the egg in its changes, a little circular,
shallow glass cell, fixed by cement on to an ordinary microscopic
glass slide, is useful. This cell must be filled brimful of water.
To take up the egg, procure a piece of narrow gloss tubing about a
foot long and little more than sufficiently wide in the bore to admit
of the passage of a single egg at a time. Close one end with the
finger, and plunge the tube into the water to a depth of 6 or 8in.;
make the other end approach an egg (which must beforehand be
gently loosened if adherent), and remove the finger which closed the
tube; a current of water sets in towards the interior of the tube,
and carries the egg with it. Replacing the finger on the end of the
~ tube, the egg is retained in the tube and easily carried off. The lower
end of the tube is to be moved to the surface of the water in the
glass cell, and the egg allowed gently to sink into it, by gradually
removing the finger from the tube. The egg and surrounding
water are then covered by a piece of thin glass, care being taken to
include no bubbles of air; and the whole slide is placed on the
stage of the microscope, which stage must be fixed in a horizontal
position. Hive or six eggs may be included in the cell at the same
time, and in this way the egg contents can be observed in several
aspects at once.

I will now proceed to describe what I saw by the above means.

Unfertilized ova are found to present some of the phenomena
hereafter described, of imbibition of water into its cavity, forming
a water-chamber ; rotation and contraction of the yelk; sometimes

188 Observations on the Development — [Mpnthly, Microscopical
an imperfect cleavage, &c. So that, when I speak of fertilized ova,
I do not necessarily exclude barren ones.

Apri 14th, 8 p.u.—I did not make any observations until ten
hours had elapsed after fertilization; so that my remarks as to
what takes place during that time are constructed from what I
have heard or read. ‘The egg of the pike is a globular body, the
size of, and much resembling in colour and translucency, a grain of
cooked sago. It consists of an outer covering, and of a contained
yolk or yelk. ‘The outer covering is very elastic, and if an attempt
is made to pierce it with a sharp point, the egg springs away; so
that it is almost impossible to make an opening. We will suppose
that fertilization has taken place, and one of the eggs is placed in
the field of the microscope. The first thing observed is that the
ege becomes visibly larger in water, and this is seen to be due to
an imbibition of water, which enters by absorption through the
outer wall, separates the yelk from its previous position in con-
- tact with the wall, distends this latter structure, and forms a fluid-
medium completely surrounding the globular yelk, and wherein
it can freely rotate. This water cavity serves, doubtless, by con-
stant change of the water, as a respiratory medium for the yelk
and the embryo fish that is formed upon its surface. Over the
surface of the yelk is seen spread out a thin layer of material
in the state of granules, or very small particles, which layer is the
structure from which the embryo is formed. At first this layer is
laid over the whole surface, but collected more especially towards
a pole termed the germinal pole, which corresponds to the situa-
tion of the micropyle. (See Fig. 1: a, the elastic cell-wall; },
the water cavity between it; and e, the yelk, covered with a layer
of granules, which are more densely aggregated towards d, the
germinal pole and micropyle.) Very shortly, the granular matter
collects more markedly at the germinal pole, gradually passes over
to it almost entirely, leaving the remaining surface uncovered ; and
the mass forms a projection on the otherwise circular outline of the
yelk (Fig. 2). This germinal mass, consisting of an aggregation of
eranules, next undergoes cleavage: a furrow forms across it, divid-
ing it into two parts; then another forms at mght angles to the
first, dividing the whole into four (Fig. 3, where the germinal
mass is seen in face, and not in contour). Division goes on into 16,
64, &c., until the mass is minutely divided, and is then in the
so-called mulberry stage. It is finally broken up to such a degree
that the surface becomes smooth again. It now subsides, as a cir-
cular disc, to the under-surface of which is attached a layer of oil-
globules.

As soon as the water-breathing chamber is formed, appear the
phenomena of contraction and oscillation of the yelk within the yelk
cavity. On the circular outline of the yelk appears a shallow in-

MJournal, Oot. 1, 1669. of the Ovum of the Pike. 189

dentation : this indentation travels round the yelk and completes
the circle. This zone of indentation, which is equatorial, and in
the median line, travels onwards towards the germinal pole, the
yelk assuming successively the outline of a dumb-bell, a flask, and a
sphere surmounted by a little cone. By means of this indentation,
the lateral half im which it first occurs is rendered less weighty
than the other half, and hence it rises. By this means a swinging
movement is set up, whereby the germinal pole moves from side to
side, but never passing so low as the horizontal axis of the egg-
shell. At first the germinal mass (carried by the yelk) moves
almost exactly in a straight line, to and fro; by-and-by, the mass
moves in a widely-elliptical orbit around the north pole of the
vertical axis of the egg-shell, not dipping below an angle of 45°.

This oscillation takes place now from east to west, now from
west to east: a slight interval of time separating the two move-
ments. Variations frequently occur. This oscillation goes on so
long as the egg is in vital activity, up to the moment when
hatching takes place; and by this rotation the aération of every
part of the embryonic surface by the water around is more com-
pletely ensured. (Fig. 5 represents the situation of the orbit in
which the germinal mass moves around a, the north pole, seen in
face.) These movements of oscillation are truly wonderful to
witness: the yelk mass moves of itself in an orderly, regular,
almost circular round, within the immovable egg-shell.

We spoke of the germinal mass last, as a circular disc, in a
state of subdivision. This subdivision goes on until the subdivi-
sions are very small. These cells, as we may call them, aggregate
towards the germinal pole of the yelk, and form there a dark and
projecting mass. The cells on the outside or periphery of the disc
multiply and increase, until the surface of the yelk is covered by
their growth. There is, then, a thin layer of ceils spread over the
yelk, with a central denser portion of a somewhat globular form, and
consisting of cells larger than those of the periphery. In my ob-
servations the germinal matter had increased by cell multiplication,
so as to nearly cover the whole surface in thirty hours after fertiliza-
tion. On the third day I saw that this mass was divided into two
parts by a longitudinal furrow. This is the first rudiment of the
embryo, and is known as the “ primitive groove.” I next observed
two straight faint lines, parallel with the primitive groove, extending
the whole length of the furrow, marking out the “notochord,” or
“chorda dorsalis,” and also the spinal cord. It is the rudiment of
the spinal column. Above this, or “dorsal” to it, is formed the
spinal cord: below it, or “ventrally,” the nutritive system, heart,
viscera, &c. These lines start from one point, and run round the
yelk until they reach a point diametrically opposite to the com-
mencement: each termination is surrounded by an outspread layer

5 : Monthly Mi i
190 Observations on the Development IAT wig Om

of granules. On each side of the median furrow the granules or
cells collect, forming a little mound co-extensive with the furrow in
length. These mounds eventually arch over the furrow and unite,
thus enclosing a space, in which is formed the spinal cord and
brain. Running across the two longitudinal lines (the axis of the
germ) are lines which represent the vertebral rudiments. (Fig. 6
shows the median furrow, the two straight lines parallel with it, and
one extremity of the embryo.) On each side of the median furrow,
and above the notochord, 1s formed the half of the spinal cord and
brain, so that the cord contains a cavity within, when the two halves
unite above by arching over. At this period we have, next to the
yelk, a cylindrical body, the notochord: above it, the spinal-cord
rudiment, separated into halves by the median furrow, and termi-
nating in a cephalic, and a caudal, rounded extremity: the whole
encircling one-half or three-fourths of the yelk. 40 hours.—The
cephalic extremity is pomted: on either side is an inbending of
the lateral line, marking off the position of the mesencephalon or
middle lobe of the brain (Fig. 7). In profile the embryo is seen to
form an elevated mass on the surface of the yelk; the rudiments of
four vertebrae, or bones composing the spinal column, are observable,
commencing below the cephalic inflection. (Fig. 8: a, cephalic ex-
tremity ; b, rudiments of vertebrae, being segmentation or division
of the notochord; ¢, caudal extremity.) 52 hours.—The cephalic
extremity resembles a leaf of clover, being divided into three lobes:
the anterior one, the anterior lobe of the brain; the two lateral
lobes, the median lobe of the brain, and the eyes. Behind the
middle lobe of the brain is a third and smaller one. (Fig. 9, the
three lobes seen laterally, at a; a wave of indentation is also seen.)
(Fig. 10 shows, a, the anterior lobe; b, median lobe, with a vesicle
on either side, the rudiment of the eye; ¢, the posterior lobe; also
several rudimentary vertebree, and the ventricle or cavity between
the halves of the spinal cord.) Twelve vertebral segments are
discernible: the cavity occupied by the spinal cord is seen running
along their summit. 58 hours.—The spinal cord is seen extend-
ing from the eyes to the tail, widening just below the eyes,
and then preserving the same width to the tail. It is divided
into halves by a median sulcus or furrow. 17th April, 10 a.m.,
72 hours.—The eye has a central lens, an iris, and a round band
encircling both. ‘The ear appears as a somewhat quadrangular
capsule, enclosing smaller ones, on the side of the brain mass. The
heart also is seen, as a tube bent upon itself, somewhat anterior to
the position of the ear. From the heart passes a vessel upwards
and towards the tail, but at present it extends no farther than
first vertebra. A fold of membrane is reflected from the under-
part of the head, which includes the rudimentary heart. (Fig. 11
shows, a, the eye; b, the including membrane; c, the heart, with

a oe. ae, of the Ovum of the Pike. 191

the vessel proceeding from it; also the vertebree, and the rounded
tail.) (Fig. 12 shows, f, the ear-capsule; g, the membrane en-
closing the heart; it also shows the union of the halves of the
brain in front, and the folding of the mass to form the division
between the lobes of the brain; and the median sulcus or
canal.) 5 p.m., 79 hours.—The yelk surface is occupied by round
clear spaces in which blood-corpuscles can be seen. This was the
first time I had seen any, and I had watched very closely for their
appearance. By means of the contractions in the yelk, formerly
mentioned, the surface is thrown into a series of wavy folds. In
the furrows between these little ridges are numerous blood-globules,
which are passing towards the precordial area. There are blood-
globules on both right and left sides of the yelk. The precordial
area is of a clear white colour, and empty: no blood as yet has
reached it; and it is to be observed that the heart is motionless,—
that the blood flows to the heart independently of the heart’s action.
The blood-corpuscles are colourless at present. The oscillation of -
the embryo and yelk is vigorous. (Fig. 13 shows the wavy folds
which apparently were the means of the movement of the blood-
corpuscle on to the heart.) 11.15 p.m., 854 hours.—Blood-corpuscles
have reached and entered the precordial area. 11.30 p.m.—There is
in the embryo a duct leading from the interior of the yelk into the
digestive canal; by this means nourishment is conveyed to the em-
bryo, and it is probable that the yelk contractions are the agents in
propelling the yelk into the canal. (Fig. 14 shows this duct.)
18th April, 10 to 12 a.m., 96 to 98 hours.—For the first time I
observed the heart to be beating, yet no blood-corpuscles were pass-
ing through it. So that it is evident that the contractions of the
heart are independent of any stimulus given by the presence of
blood-corpuscles within its chambers. The heart in the adult fish
consists, not of four chambers, as in the mammalia, but only of
two—first, an auricle to receive and collect blood ; immediately
succeeding to this a ventricle to contract on the fluid contents and
force them onwards. Suceeeding to this is the dilatation of the
efferent vessel known as the bulbus arteriosus. In the case before
us the heart consisted of a bag-shaped organ, divided into anterior
and posterior chambers, the former being the wider of the two, and
communicating by a circular constricted portion with the ventricle.
The posterior chamber consists of two broad flaps, connected by a
thinner structure ; the flaps move to and from each other, and thus
are capable of producing an intermittency of current by shutting
off the supply of blood during the auricular contraction. It may
be pointed out that this period is a most favourable one for investi-
gating the nature of the movements of the heart. The structures
are all nearly as transparent as glass, and there is no current of
blood, so that the conditions are eminently favourable for observa-

192 Observations on the Development = [yee ores

tion. The posterior chamber is seen to close-to, like two flat
boards coming together; then the anterior one contracts, the con-
traction travelling along, vermicularly, as it is called, or with a
movement like that seen in the locomotion of the earthworm.
(Fig. 15: a, the posterior, b, the anterior chamber; one of the
figures shows the flap-like sides of the posterior chamber, the other
the circular constriction between the two cavities.) It is interesting
to note that at the same time that contractions occur in the heart
for the first time, they also occur in the muscles forming along the
back of the embryo, which is thus seen to endeavour as it were
to straighten itself out.

Coincidently with these changes resulting in the formation of
the heart, the formation of the whole body is proceeding with
rapidity. By this time the embryo consists of a head, with brain,
eyes, and ears, a heart, and a vessel proceeding from it to go down
the body underneath the vertebre, a long chain of vertebrae termi-
nating a little distance from the tail, which latter terminates in a
moderately pointed manner ; above the vertebral bodies, the spinal
cord with its median furrow ; these again covered in by muscle and
integument. The embryo reposing on and laying around the yelk-
bag, from which the creature derives its nourishment, and on the
surface of which blood-corpuscles are seen passing to the leart,
the whole oscillating within the water-chamber enclosed by the
elastic egg-wall. |

12.30 p.m., 984 hours.—The heart beats 104 times per minute.
The two cavities contract and dilate alternately; the posterior
contracts whilst the anterior dilates, and vice versd. 5.30 P.M.,
1034 hours.—By this time, the tail-half is detached from the yelk
surface, and is now lying free in the water-chamber (Fig. 16).
The yelk-sac is diminishing in size, the growth of the embryo re-
moving the contents gradually by absorption. 10.45 p.m., 1082
hours.—Circulation of blood seen for the first time. At this ear-
liest period the course taken by the blood is as follows :—Two
currents of blood are seen passing towards the auricle, one running
along the median line of the yelk surface; the other comes from
under the body, probably from the other side of the yelk, below
a structure situated a little nearer the tail than the heart. These
may be called veins. The blood in these two currents uniting, enters
the precordial space, passes through the posterior and anterior
cavities, and then, by a large vessel or artery, which immediately
divides into two, is carried to the under-surface of the ear, making
a sharp curve; two vessels pass as far as to the first vertebra, where
they unite, and the united artery passes underneath the vertebrae to
a point where the body is disjomed from the yelk. Here the blood
runs on to the mid-line of the yelk, and reaches the point whence it
started. (Fig. 17: a, b, the two currents; d, the auditory cap-

Py Ole ses. of the Ovuin of the Prke. 193
sule, or ear; ¢, the point where the arterial current runs on to
the yelk.) Very soon the arterial current, instead of running on
to the yelk atc, passes farther along under the vertebral column,
makes a very acute bend, and returns by a vein to the yelk (Fig. 18).
This prolongation gradually lengthens until the tail-end is reached.
11.45.—Fish, as is well known, breathe by means of gills, or
branchize. These consist of a multitude of very fine blood-vessels,
which lie freely exposed to the surrounding water. At the period last
indicated I saw the first rudiments of the branchial apparatus appear.
The position of the branchial arteries is represented in Figs. 19
and 20. Fig. 19: a is the as yet undivided primitive artery, and b
one of the branchial arteries. Vig. 20: d is a branchial artery repre-.
sented in position, the one of the other side being unseen ; ¢ being
the heart. Fig. 20 represents a stage more advanced than the
present one, but is introduced here to show position of the branchie.
At this period, 11.45 p.m., I observed a structure (marked by cross-
hatching surrounding letter d, Fig. 20), obliquely crossing which
subsequently became developed the branchial arteries and the sup-
porting arches. At this time I noticed the division of the main
trunk into left and right, the left curving upwards and around the
rudimental branchial structure running underneath ¢, the auditory
capsule, to join its fellow of the right side (not seen). This right
trunk passes underneath the head, makes a similar curl upwards
and backwards, and, in fact, strictly corresponds to the leit one.
These may be called the right and left primitive trunks. The heart
now appears as a thick walled tube, dilated into posterior and
anterior chambers, the former being the larger. The anterior is
curved, and the valvular action between it and the posterior con-
sists of an inflection of the wall, whose outside edge is concave, into
the cavity of the other wall, fitting like a knee into the hollow, and
so shutting off the current. Fig. 21: a, posterior chamber ; 4,
anterior, with the knee-like valve. Pulse now 90 per minute, being
a fall of 14 per minute since 12.30 (114 hours ago). Blood-
corpuscles are being detached from the yelk surface, where they
had their origin, and pass to the opening of the heart. Fig. 22:
a, the right eye; b, posterior chamber—the right primitive trunk is
seen passing underneath the head; ¢, the thin line, marks off a
space around the heart, a receptacle for the blood before entrance
into the heart, which I have called the precordial area; d, the
ege-shell. The precordial area is marked out by a white immov-
able rim; corpuscles pass through certain gaps which remain con-
stant, as the corpuscles may be seen to pass along the rim for a
httle distance to reach an opening. Before reaching the rim they
advance at a uniform rate; after they have passed the boundary
they are repelled slightly with each beating of the heart. There
are three currents seen from the left side entering the heart
VOL. II. P

. Monthly Mi ical
194 Observations on the Development tt

(marked by three arrows in Fig. 20): one (1) from the left side of
the yelk surface ; another (ir) from the neighbourhood of the mouth,
entering anteriorly (and coming from the right side of the yelk
surface) ; the third (111) from the position of the branchial structure,
entering posteriorly. The optic capsule (a, Fig. 22) is becoming
lengthened and curved on itself, so as to form a U-shaped body ; in
the concavity of this the circular lens is formed. The olfactory
capsules, the organs of smell, are visible (the two oval bodies at e,
one on either side of the middle line) as small depressions in the
snout; fis the nervous cord which represents the left side of the
brain at the present stage. It ig seen to unite with its fellow in
front, and between the two is a cavity called a ventricle. There
are strong movements of flexion in the back, the head bending
towards the tail and the tail towards the head.

19th April, 6th day, 12.15 noon.—Looking at the right side of
the embryo, the right primitive trunk is seen crossing from the left
side, making a sudden turn upwards and pursuing a curvilinear
horizontal course underneath the organ of hearing, as on the left
side. Fig. 23: ¢, same figure; a, ventricle of brain ; 6, folding-in
of the cerebral cord to form a lobe, the middle or mesocephalic lobe ;
d, the commencement of the left primitive trunk; e, the pracordial
area—in front and behind this letter are the two currents mentioned
as coming from the right side of the yelk surface (Fig. 20). The
veins from the head on either side coalesce, and take the course
shown (for the left side) in Fig. 20, running from the eye, passing
above the auditory capsule, then descending, arrive upon the yelk
surface in the precordial area. On the right side (Fig. 23) it passes
under the head. At g (Fig. 20) this current and the venous supply
from the left side are seen uniting, to pass on to the heart. ‘The
venous and arterial currents cross each other, as is seen at f, Fig. 20,
the artery being underneath. ‘This crossing has led some errone-
ously to suppose that the two currents, venous and arterial, united.

Fig. 24 is a diagram of these currents: a, the cardiac opening ;
(1) right, (11) left, yelk current; (111) left head venous current ; (1v)
right ditto. The head is attached to the yelk surface by a broad
band (h, Fig. 20), and it is posteriorly to this that the current from
the right side passes. The optic capsule, mentioned at 11.45 p.m.
of 18th, as a U-shaped body, has now the two ends united, so that
the lens is encircled (b, Fig. 20).

20th April, Tth day: 1 a.m., midnight.—A current of blood is
seen to pass down the aorta, under the vertebra, nearly to the
end of the tail. The aorta terminates by a small vessel, turning on
itself, in a very large vein: the blood runs along the vein to the
extremity of the yelk nearest to the tail, and is emptied on to the
yelk surface; there being a vein or venous channel on each side of
the yelk, which runs on its border to the heart (d, Fig. 18).

Beer Oct Lines of the Ovum of the Prke. 195

9.30 a.m.—Two otoliths, or small ear-stones, were seen in
the auditory capsule. The little bodies in ¢, Fig. 20, are otoliths.
9.45 a.m.—There are indications of two arches forming, passing
along in the situation of the future branchie (d, Fig. 20). 11.15
p.m.—The embryo has grown completely round the yelk, and the
head now touches the tail.

21st April, 8th day: 5 p.m. 175 hours.—I found one of the
eges hatched. I had not counted the number of eggs under obser-
vation, but find included in the following catalogue 465. Many
besides these became addled (being opaque white instead of semi-
transparent yellow), and offensive to the nose. These were removed,
so that we may estimate the whole of them, in round numbers, at
500. The hatching extended over five days; the majority being
hatched on the 23rd April, being the tenth day after fertilization.

On the 14th April I took 500 eggs.

21st, or 8th day, were hatched 12, or 2°4 per cent.
1 °

22nd ,, 9th ,, ‘i Eee OR GY ee
93rd ,, 10th ,, ‘ 197 SOAP es
oft. Vidh 4, A OF iyi hOed Jiiiisy
25th ,, 12th ,, Boy tae

99 16 99
add, 35 addled, 35 ,, 7:0 ‘.

500 100

The fish made their exit from the shell, some with the yelk-bag
first, some with the tail, the majority with the head: their escape
was effected by means of forcible, wriggling contractions of the body.
After their exit, some lay motionless at the bottom of the vessel,
whilst others, applying the muzzle to the leaf of a water-plant,
adhered to it by means of an adhesive material secreted by a gland
in that situation, and so hung, suspended from the leaf. This adhe-
sive matter was gradually drawn longer and longer by the weight
of the fish, until a thread as long as the little fish itself was formed.
Adhesion was seen to be instantaneously effected upon application
of the tiny muzzle to the leaf; sometimes there might be. seen a
cluster of two or three suspended from one point, or a couple hang-
ing from the body of a third.

The recently-hatched fish had not all reached the same stage of
development ; for whilst in some the movements of the body were
vigorous, and the circulation actively going on, others, lying motion-
less, would show no circulation of blood whatever. At a further
stage, as for instance about the 16th or 17th day, at a time when
the branchial fringes are in formation, all seemed to be alike with
respect to the degree of development.

22nd April, 9th day.—State of the circulation immediately after
extrusion from theegg. (See Fig. 39.)

The heart (a), consisting of posterior and anterior chambers, lies

p 2

196 Observations on the Development — [Moths Mjcrorcanica
exposed on the yelk-bag. rom the anterior is continued a large
arterial trunk, which speedily divides into right and left, the first
arterial arch; that for the left side (b) passes upwards ; the other, for
the right side, crosses underneath the head, reaches a similar position
and pursues a similar course to that of the left arch. Just before
turning along the upper edge of the branchial rudimental structure,
each trunk gives off two branches (seen atc); the first, a small one,
forwards towards the mouth (the orbito-nasal) ; the second, by far
the larger, passes upwards, and supplies the head (the carotid).
The diminished trunk makes a great and sudden turn, and runs along
the upper edge of the branchial rudiment, and below the ear (d).
Across the space for the branchiz are seen stretching two mem-
branous arches, which extend from the heart to the continuation
of the first arterial arch. These membranous arches are for the
support of a series of vessels, the branchial arteries, four in number
(on each side), when complete; the number of bony (as hereafter
they are) arches, when complete, being five. Between these two
rudimentary arches is seen a faint arterial current passing from
the primitive vessel before division to the arterial trunk above, and
entering it. Ata later hour three spaces were seen, enclosing two
blood-currents (as at e). These structures, when fully developed,
form the gills, or breathing apparatus. The first arterial arch con-
sists of the portion from the heart toc. After this point it forms,
with its fellow of the opposite side, the aortic circle, extending from
c to f, where it joins its fellow underneath the vertebral axis. From
c, the half of the circle runs downwards, lying underneath a large
vein (the cephalic or jugular), until this vein turns downwards to
enter the auricular sinus, a sort of antechamber to the heart (g),
where the venous current may be seen to cross over the arterial at
right angles. From this last point the vessel curves slightly upwards
and inwards, joins its fellow, and the conjoined vessel constitutes
the aorta. ‘This passes down along the body, being placed between
the vertebral structures and the intestine, nearly to the end of the
tail. From the whole length of the aorta are given off at regular
intervals arteries that pass directly backwards to the dorsal border
of the fish, apparently marking out, or running between, the seg-
ments of the vertebral axis. (Fig. 25: a, spinal cord; b, segments
of vertebral axis ; c, intestine ; d, aorta, giving off vessels.) At the
dorsal border these vessels form a system of capillaries, from which
return a number of veins similar in number and situation to the
arteries, and which ultimately, by means of cross-currents, seen at
m and n, reach the great venous canal lying below the aorta. This
channel, the cardinal vein, commences near the extremity of the
tail, there being one on each side; the narrowed aorta terminating
in them by a complete turn on itself (Fig. 39, h). The vein runs
along directly underneath or below the aorta, as far as the point

PA Ost L toes, of the Ovum of the Pike. 197

where the intestine turns downwards through the tail membrane to
the aperture of exit (7). At the bend (/) the vein crosses the intes-
tine, and becomes placed underneath it, until it reaches the poste-
rior tapering end of the yelk-bag (/, the intestine, traceable upwards
to the mouth, the letters g, e, and b being placed on it; and down-
wards by & to its termination, 7; m, the posterior end of the yelk-
bag). During its passage from h to m, it receives, first, a large vein
at k, which can be traced forwards (mouthwards), lying just below
the aorta, and which receives the veins corresponding to the dorsal
arteries shown in Fig. 25; from this vein pass two or three com-
munications to the cardinal vein, higher up than the principal
junction at k, as marked at n; 2ndly, a vein, seen at m, which
turns round the tapering extremity of the yelk-bag, and joins the
main vein.

These two veins would appear to return venous blood into the
cardinal vein from the body below the point f. The cardinal vein
thus formed of three conjoined currents passes along the ventral
border of the yelk-bag, the blood as yet spreading but little over the
sides or general surface; it passes then in the median line around
the yelk-bag until it reaches its junction with the mouth (0), when
it meets current a, then turns inwards and meets current 6. This
latter current is the return blood from the head (muzzle to /), and
is formed as follows:—The superficial veins of the head converge
from all points to two large veins, which pass one above and the
other below the ear (seen above and below d); into the one above
the ear enters a third, which appears to come from the deep parts
of the head. The vein above and that below at length unite
behind the ear, and the resulting vein crosses the aortic circle and
the intestine, and finally runs out by a round aperture into the
auricular sinus (7). This is the case on the left side; on the right
side, after the blood has reached the surface of the yelk-bag it turns
and goes underneath the head ; reaching the point g, the nght and
left currents run parallel, a clear interval remaining between them,
until they reach the heart, the two forming current 8.

A portion of the blood from the right cardinal vein passes along
the right side of the yelk-bag to the muzzle, and there crosses over
to the left’ by the junction of the muzzle and yelk-bag, forming
current a (seen ato). The remainder runs downwards to join the
right-side current from the head, which passes under the head to g.
The current from the left cardinal vem meets current « at the
muzzle of the fish, passes onwards to the heart, and at the entrance
to the auricle meets current 8, coming from a diametrically opposite
point; the two run into the auricle by the side nearest to each,
mingle, and enter the ventricle—the place whence we started.

In the eye is seen the iris (s),a broad band surrounding a round
space, a line where two extremities of the band have united being

198 Observations on the Developinent — [Mpnthly, Microscopical

evident at the lowermost part. In the round space it encloses is
the lens, contained in a well-defined capsule ; the outline of both
is perfectly circular. The mouth, or rather the situation of the future
mouth, presents rows of rounded papille (7), doubtless the source
of the adhesive thread by which the fish suspends itself. ‘The duct
from the yelk-bag to the intestines is to be seen. ‘he pectoral
and dorsal fins are commencing to be developed.

23rd April, 10th day.—The primitive trunk seen coming off
from the ventricle shows three divisions, two being right and left
first arterial arches, the third the main branchial artery, which gives
off branches to each side to form the other arterial arches. ‘The
rudiments of four branchial arches are now seen between the heart
and the aortic circle. Between these arches are seen, in some of
the fish, one, in others three arterial currents, the third being very
small. These currents enter the aortic circle.

Arterial currents are seen to pass behind the eye, ascending from
the region of the mouth, and also in front of the eye, near the
olfactory organ (t). The venous system appears the same as on the
22nd. I observed that part of the venous return from the head,
instead of coming from g to the heart, passed tailwards between
the imtestine and the yelk-bag, and entered the vein which joins the
cardinal vein at m.

The olfactory organ (¢) is situated in front of the eye, at the ex-
tremity of the muzzle, and has an oval outline. The pectoral fin
(p) gives faint vibratory movements.

The heart is now becoming more enclosed in the growing
branchial structures, and placed more in the middle line. The blood
which issues from the cardinal vein on to the yelk-bag is not now
confined to the median line, it spreads over the whole surface, run-
ning in furrows or channels, having no distinct walls as a vein has.
It is streaming all over in numberless paths, all tending to the
heart. The object of this is to expose the blood more completely
to the action of the water, whereby a respiratory process 1s effected.
The blood, depreciated by its course through the tissues, is no longer
sufficiently subjected to the action of the water, owing to the fish
growing rapidly and becoming more dense, a greater distance being
interposed between the blood-vessels and the water. ‘To remedy
this, the great vein distributes its contents over the wide surface of
the yelk-bag, where the blood is freely exposed to the surrounding
element. In fact, this distribution of the blood in a large number
of channels over the yelk-bag is a temporary breathing apparatus,
which is designed to eflect respiratory changes until the branchize
or gills are ready to perform that office. (Fig. 26 is an exceedingly
rough diagram, showing the course of the blood from , the entrance
of the vein on to the yelk-bag, to a, the heart.) The ramifications
of the vein are very numerous, and the blood-corpuscles hurrying

So eee of the Ovum of the Pike. 199

with great velocity through the winding ways 1s a most beautiful
object to witness. :

24th April, 11th day.—In the fully developed state there are
five bony arches, called branchial arches; of the four anterior of
these each one supports a branchial artery ; these four branchial
arteries with the first trunk extending from the heart to the aortic
circle, constitute the five arterial arches which are given off on each
side in the embryo. The second arterial arch, or the first branchial
artery, is much increased in diameter, being now as wide a vessel
as the first arterial arch; two rudimental branchial bones stretch
completely across the branchial region; two others are seen poste-
rior to the first two, and as yet very small.

The circulation of blood over the yelk-sac is more extensively
ramified to-day than it was yesterday. Other changes are occurring
in the vein mentioned as passing from g to m (Fig. 39), but as the
description would be uninteresting to the general reader, I omit it.

20th Apri, 12th day.—Slender, well-defined vessels are in pro-
cess of formation in the membranous expansion around the caudal
termination (tail-end) of the fish. They frequently join each other,
but do not communicate with any vessel from the heart, being
isolated and bloodless. This shows that blood-vessels are laid down,
as it were, and grow independently of any connection with the
heart. Vessels are also shooting out from the side of the bony axis
of the tail, in a direction suitable for meeting the isolated ones
mentioned. The branchial arches now bend more decidedly, the
convexity being towards the tail. The tail membrane now shows a
deep cleft on its dorsal borders, indicating the approaching forma-
tion of the dorsal fin (wu). Pigment cells are beginning to show
themselves on the parietes of the body.

In a fish which had been put into shallow water, under a cover,
and which had exhausted apparently all the contained oxygen of
the water, the heart’s action ceased. The blood ceasing to be im-
pelled forwards from the auricle, that contained in the aortic circle
flowed in a reverse direction, backwards. This was interesting, as
showing the elastic recoil of the artery. But when by means of
the branchial arteries this aortic blood had again reached the heart,
it passed completely through it until it reached the auricular sinus.
Arrived there, it immediately reverses its course again, enters the
heart, causes the heart’s pulsation again to take place, and by that
means again reaches the branchial arteries and the aorta. I suppose
that the blood, having reached this spot, was in a better position for
aération than elsewhere, and therefore more resembled the natural
stimulus to the heart’s action, as this very strange oscillatory action
was repeated many times, the whole lasting some few minutes.

26th Apri, 13th day.—I observed four well-marked branchial
arches springing from their centre, the hyoid bone; and in addition

200 Observations on the Development = [yay oer eile
to the three before seen, a fourth branchial artery. These four,
with the primitive arch, complete the normal number of five
arterial arches. As the first branchial artery, the second arterial
arch, increases In size, the first arch rapidly diminishes. ‘The sub-
sequent changes, noticed as long as they could be seen, were as
follows :—The heart, by the diminished bulk of the yelk-bag, &c.,
becomes more central, the anterior chamber retains its old position,
but the posterior, instead of being external, is now internal to the
anterior. ‘This change of position would appear to take place in
some such way as this (Fig. 29) :—By the rapid growth and deve-
lopment of structures near to the heart, closing in the precordial
area, the large veins become median to the axis of the body; the
posterior chamber into which they enter is drawn after them,
bending, we may imagine, round an axis 2, #, inwards, whilst the
prominent wall of the anterior chamber sinks down from a to a’,
so that the appearance of the heart as last seen was that of Fig. 28,
where the arrows indicate the direction of the blood-current—a, the
posterior, b, the anterior chamber. The course of the blood through
the heart is seen to be remarkably serpentine.

I am disposed to look upon these heart cavities as follows :—
(Fig. 22) the space in which c is placed, as the auricle; (Fig. 39)
the space in which a is placed, as the pericardium ; and the posterior
and anterior chambers, as the ventricle, and bulbus arteriosus.

In the branchial system of vessels a most singular change takes
place, whereby the direction of the blood-current in a portion of the
main vessel is reversed. Before this change occurs, the course of
the blood is as follows (Fig. 30) :—Starting from the heart it divides
at g, into k, the branchial arteries which enter the aortic circle, and
g, the primitive arterial trunk; the latter ascends to 2, and there
gives off supplies to the mouth, eye, and head, subsequently form-
ing part of the aortic circle, and running downwards. After a time,
fourteenth or fifteenth day, a small vessel (2) forms, running from
the first branchial artery (h) to the primitive trunk. ‘This is the
venous or refluent branch of the first branchial artery. This last-
named artery increases in size, and in a corresponding degree the
primitive trunk not only ceases to enlarge, but becomes less. At
last a slight ridge appears between the first and second vascular
arches (at g); this ridge grows forward so as to press upon the
primitive trunk. By means of this pressure the artery gradually
dwindles away until it is obliterated from g to 7. The course of
the blood now is that of the adult circulation. It passes from the
heart to the first (second, third, and fourth) branchial arteries, and
enters the aortic circle. Part goes downwards, part goes upwards »
in a direction diametrically opposed to the former course, running
from m to ¢, where it gives off a, the carotid, to supply the head ;
d, e, the orbits nasal, for the structures protecting the organs of

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Monthiy Microsconical! oF the Ovum of the Pike. 201

sight and smell; and (the vessel from to g being obliterated) ends
its course in the refluent branch, /, of the first branchial artery.
This vessel does not enter the branchial, but it terminates in a
pseudo-branchial apparatus, or false gill, in the situation 7. After
supplying this apparatus the return blood from this false gill is
collected into a vessel (s), which supplies the eye with blood, and
hence is called the ophthalmic. Fig. 31 shows diagrammatically
the remarkable change that takes place.

As circulation becomes well established in the branchie so that
respiratory changes can take place to a considerable extent, the sur-
face of the yelk-bag is less needed as a breathing apparatus; the
channels appear to obtain walls of their own; they diminish, in
number ; the yelk-bag becomes darker in consequence of numerous
pigment cells becoming scattered over its surface, and lessens in
size, the vessels doubtless becoming cutaneous veins, and entering
the large or cardinal vein, which empties itself into the auricular
sinus.

In order to protect the delicate structures of the gill from exter-
nal injury, a movable covering or flap is placed over it: this is
called the operculum (the dark line commencing at h, Fig. 32,
shows the outline). This structure is continually in movement,
flapping to and fro; and by means of this movement the water
which is taken into the mouth is, when the mouth is closed, driven
through the branchial interspaces. The operculum at first is trans-
parent, and covers the branchial and precordial spaces and the
auricular sinus completely. ‘The to-and-fro movement takes place
twenty-five times in a minute, whilst the beats of the heart are 100.
It is interesting to notice that the ratio of inspiratory and cardiac
movements is the same as that of the human subject. In the case of
man, the respiratory act occurs eighteen times per minute, and the
cardiac movement seventy-two times, or four times as often, just as
we find it in the fish. At the edge of the firm operculum is a trans-
parent, thin, structureless membrane, which also moves to and fro
with each respiratory effort, so that the edge of it describes a curve
of a quarter of a circle: this is the branchiostegous membrane.
Behind this, and indeed touched by it, is the pectoral fin (a, Fig. 33,
which is a view from the back of the fish; it projects outwards).
This fin is m a state of constant and rapid tremulous motion. The
Os Hyoides (i, Fig. 32), with its attached branchial arches, moves
at a joint seen at /. In the first place the mouth is opened, and
water is taken into its cavity; at the same time, the hyoid bone,
with its attached structures, including the operculum, moves down-
wards, as it necessarily must do when the lower lip is depressed ;
and the operculum opens widely. The mouth then closes; by this
means the hyoid bone is drawn upwards, the cavity of the mouth
is lessened, and part of the water escapes through the gills, aérating

202 Observations on the Development — [Mpnthly, Microscopical

the blood in its passage : lastly, the operculum closes, expelling most
of the remainder. ‘To support the delicate branchiostegous mem-
brane, four bony processes are given off from the Os Hyoides. The
blood-currents through the gills are next subdivided and broken up
into an innumerable series of small vascular loops, by which means
the blood is more thoroughly exposed to the purifying action of
the water. It is only the commencement of this development which
can be seen by the microscope, as pigment cells grow rapidly and
obscure the parts beneath. The first step is the budding of the
branchial arch into a set of tubercles, as at a, Fig. 35. These
tubercles support a set of small vessels or villi, little vascular
loops, which spring from the branchial artery, and transmit the
blood-corpuscles in single file. The tubercles increase in size, and
form a broadish leaf-like structure, of which there are a great
number, springing from each arch. These leaflets support the sub-
divisions of the branchial artery: along the edge of each leaflet
the artery is split up into many capillary vessels; these coalesce to
form a vein containing aérated blood. The branchial artery divides
lengthwise (Fig. 37) into artery and vein, the former tapering from
the heart extremity to the aortic one, and giving off continually a
branch to each leaflet as it passes along the branchial arch, the vein
being parallel with it, but tapermg in the other direction, being
smallest where the artery is largest, and becoming larger as it
receives the coalesced capillaries and advances past each leaflet to
the aortic circle. Fig. 35: a, the leaflets as they are seen at first
Fig. 386, a, being another view); 0, the villi, as first seen; ¢, the
two together ; d, pectoral fin; e, the intestine; f, liver; g, the yelk-
ball, much shrunk by absorption of the vitellus. Fig. 36, b, ¢, d,
the capillary loops; Fig. 37, diagram of a, the branchial artery ;
b, the branchial vein, with the intervening capillaries. ‘The first
villi were seen about the 28th April, 15th day. They then showed,
as simple loops, the blood discs ascending, curling round, and de-
scending. On the 30th the loop appeared spread out, almost circu-
larly, and was bent, and sometimes twisted on itself (¢, d, 36).
They were increasing in length, and were beginning to subdivide,
as seen at b, 33. Pulsation was evident in the loop. After this
period the rapid increase of pigment prevented further observations
on this point. On the 27th, in the auditory capsule, I observed
three semicircular canals (Fig. 38), and an ampulla (a), into the
dilated extremity of which two ends of one and one end of a second
may be seen to enter. At the base of the ampulla is an otolith.
The relations of the other otolith and the other terminations of the
canals cannot be made out.

This brief abstract being now concluded, I have only to recapi-
tulate the chief points observed by me.

The blood-corpuscles flow to the heart before the heart has

ee OtL Liao. of the Ovum of the Pike. 203

commenced to beat: the flow is therefore independent of the heart’s
action at this period.

The embryo is nourished by the vitellus contained in its yelk-
bag until the time when the mouth is open and prey can be
caught.

‘The heart was observed to beat before blood-corpuscles were
within its cavity, showing that its contractions at that time at
least did not depend on the stimulus afforded by the blood-cor-

uscles.

‘ The respiratory changes in the blood were effected, in the first
place, in the veins on the surface of the yelk-bag, and respiration
took place at first before the blood reached the heart. ‘This is the
permanent condition amongst the Mollusca. After a time, the
partial absorption of the yelk rendering the exposing surface less,
and the increased size of the fish, demand more extensive methods
of aérating the blood. ‘This is attained by the formation of the
gills; and then the respiratory changes occur after the blood has
passed through the heart.

In Mammals, after birth, and in birds and reptiles after extru-
sion from the egg, a complete change in the course of circulation
and in the manner of respiration necessarily takes place. This does
not occur in the case of the fish: the circulation and respiration are
the same after as before extrusion from the egg; that is, so far as
any immediate change is concerned.

The blood-vessels are laid out independently of the heart; they
do not grow out from it like the branches of a tree, but are formed
in their several localities, and are afterwards united to each other,
and thus to the centre of circulation.

A remarkable change takes place in the system of blood-vessels,
whereby the direction of the current is reversed in a main vessel by
the obliteration of its origin—a somewhat parallel but not analogous
case to the obliteration of the ductus arteriosus in the Mammal, and
the diversion of the blood-current into another channel.

in other respects the adult condition of the circulation appears
to be the same as that gradually forming in the course of develop-
ment of the embryo.

; ; zs Monthly Micros ical
204 Anatomical Relations of the | oat es

IV.—The Anatomical Relations of the Cilary Muscle in Birds.
I. In the Green-breasted Pheasant.

By Henry Lawson, M.D., F.R.MLS., Lecturer on Histology in
St. Mary’s Hospital.

PLATE XXX. (lower half).

SomE years since, while working at the physiological problem of the
accommodation-power of the eye, I was led to examine the anatomical
relations of the ciliary muscle. ‘The first specimens on which I made
my observations were the eyes of mammals. But the results were
extremely unsatisfactory, from the circumstance that in the mam-
malian eye the muscle is composed of tissue of the non-striated
class. Many histologists tell us that the recognition of this sort of
muscular structure 1s easy enough ; and this is true within certain
limits. It is not difficult to say that a given mass of tissue is non-
striated muscular tissue. But when we are required to define
within exact limits the distribution of this piece of tissue, we come
to a very complex task. The fact is that the non- striated mus-
cular fibre and the connective-tissue fibre pure and simple, are so
very like each other in appearance, that when they come into con-
nection with each other, as they must in the case of the mammalian
ciliary muscle, it is next to impossible to say where the one com-
mences or the other ends.

To obviate this difficulty, I turned ‘my attention to birds,

EXPLANATION OF FIGURES.

The following letters refer in all the figures to the same structures, re-
spectively :—Co., cornea ; o ciliary muscle; sc/., sclerotic; ch., choroid; c. #.,
connective tissue (loose) ; sh., sheath.

Fic. 1 shows the relation ae the parts as shown under a low power (2 inch).
Here the whole muscle is seen in pear-shaped section, and connected
with the choroid by loose connective fibres at the border of the iris, and
more strongly with the choroid behind.

,, 2 shows part of the section under a higher power (2 inch). The connective
tissue character of the connection with iris is well seen, also the manner
in which the fibres of the ciliary muscle pass forwards and become
inserted in the sheath.

,, 3, also seen under 4 inch, shows the sclerotic with its irregular-shaped pig-
ment cells, and the fibres of the ciliary muscle, arising from the sclerotic,
and streaming obliquely forwards and inwards.

, 4, also seen under 1 inch, shows the posterior extremity of ciliary muscle,
and its relations to sclerotic and choroid. The latter having been torn
away from the sclerotic, has left the ends of the fibres which had passed
into the choroid, and by its removal have been ruptured.

5, seen under 2 inch. In this specimen the fibre was ruptured by drawing
the sheath towards the centre of the eye, and pushing sclerotic in the
opposite direction. The general course of the muscular fibres is very
clearly seen, and the loose suspensory fibres of the iris are also shown.

‘ f | : a 1 | OVW
The Monthly Microscopical Journal, Oct.1 1669. __ 12000
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Taffen West, se. W. West, im

Development of Fike Relations of Gliary muscle

Mjournal, Oot. 1 1969. Ciliary Muscle in Birds. 205

where, as Crampton and others had pointed out, the ciliary muscle
being distinctly striated, its beginning and end may be tolerably
easily made out. It was in the ‘ Ophthalmic Review ’ (for, I think,
the year 1865) that, in a paper objecting to Helmholtz’s and
Donders’ notions of the cause of accommodation, I first published
my remarks on the relations of the ciliary muscle: the eye of the
ostrich having been taken as the example. The subject, however,
has not received the attention it deserves from physiologists ; and
with a view to show that at least in birds, accommodation must be
effected in a totally different manner from that proposed by
Donders, I am led to bring the question once more under the
notice of histologists. I propose from time to time, as I may have
leisure, and as the Zoological Society may be able to furnish me
with “birds’ eyes,” to describe the relations of this remarkable
muscle in various birds, and first in the green-breasted pheasant,
the eyes of which were kindly placed at my disposal by Dr. James
Murie.

The description of the ciliary muscle in most of the text-books
is, so far as it applies to birds, extremely misleading and inaccurate.
It is generally described, both for man and birds, as a ring of mus-
cular or fibrous structure extending all round the eye at the line of
union of the sclerotic and cornea. But in birds it is really much
more than this.

If we take only the bird which forms the subject of this note, we
find that the ciliary muscle is much more than a mere ring: It is in
some measure almost a distinct coat. It may be described as a zone
or belt of muscular tissue (holding much the same sort of proportion
to the orb that the Tropic of Cancer does to the globe), whose fibres
run forwards to the line of junction of the cornea and sclerotic, and
extend backwards between the sclerotic and choroid for some lines.
In section made along the long axis of the eye, the ciliary muscle
would have an irregular pear-shape, the head of the pear being at
the sclerotico-corneal junction, and the stalk some lines behind and
between the sclerotic and cornea. The fibres are broad and somewhat
flat, of the usual faintly-yellow colour (caused by steeping structure
in chromic acid), and very beautifully striated, and they pass in a
regular stream from behind forwards, and from without obliquely
inwards, till they end generally in the sclerotico-corneal junction.
All the fibres do not pass into this line of junction. The muscle
is provided with a very tough and dense sheath of connective
tissue, which is so loaded with irregular pigment-cells as to render
the definition of the fibres at first rather difficult. But this sheath
is more than a mere envelope. It increases in thickness and tough-
ness at the sclerotico-corneal junction, and along the anterior half of
its length (along the pear-shaped part) it gives insertion to the
anterior extremity of many of the muscular fibres which are tra-

206 Anatomical Relations of the [Monthly Microscopteat

velling toward the sclerotico-corneal junction. The insertion then
of all the fibres of the ciliary muscle may be said to be the sheath
of the muscle at its anterior extremity and the inner lamina of the
cornea.

What is the origin of this muscle? In regard to this, if the
muscle of this bird examined in the present instance displays the same
relations as that of the ostrich, I have to correct a mis-statement
made in my former paper.* The origin of the fibres is not absolutely
confined to the inside of the sclerotic. Some few of them may be
traced into the choroid coat. These are a few of the most posterior
fibres; and my reason for assuming that they have an origin in the
choroid is, that when the latter is torn away the fibres are set free,
and present the usual sharply broken extremities.

The plan of manipulation I have adopted in making the obser-
vations which have led to these conclusions is this:—The eye is
first divided into two parts—from above downwards, and in the
transverse plane. The posterior half falls away with the vitreous
and lens, leaving the cornea, part of the sclerotic, the iris, part of
the choroid, and the remainder of the ciliary processes. With a
pair of scissors then this hemisphere is cut into halves. Then with
a Valentin’s knife I take a number of extremely delicate sections, at
right angles to the internal surface of the eye, and in the antero-
posterior direction. By this means I obtain specimens showing
cornea, sclerotic, choroid, iris, and ciliary muscle.

Having placed one of these sections in glycerine, a needle is
used—not to “tease out,” but merely to prevent the falling together
of the several parts. Under a low power, and with Mr. Collins’ new
dissecting microscope, this can readily be done. It is then seen
that the muscle is of the form I have described, and that the cho-
roid is united to the sclerotic at two points. One of these poits—
the anterior one, on a level with the iris—is, as shown in the draw-
ing, merely a feeble union, maintained by a few fine fibres of elastic
connective tissue. The other is a muscular union, is more posterior
—being, in fact, at the hinder extremity of the ciliary muscle—and
is formed, so far as I can see, by the passage of a few muscular
fibres into the soft substance of the choroid. At these two points,
then, there is connection of the muscle with the choroid. The
anterior one is merely a loose attachment, and a mere stroke of
the needle severs it without injuring the muscle or the choroid ; the
other is more decided, and when it is broken the two or three
muscular fibres involved in it present broken extremities.

All through the rest of its course the muscle is distinct; its
outer side firmly and inseparably blended with the sclerotic, and
its inner one bounded by its special sheath. ‘This is nearly all that
I have got to say as to the position of this muscle. My view may

* “Ophthal. Review.’

Syenrney Oct 163. Ciliary Muscle in Birds. 207

be wrong. I don’t thinkit is. But supposing it right, I would ask,
What effect can this muscle have on the consistence of the lens, from
which it is so distant ? How can it advance the lens through the
action on choroid, to which its attachment is so far posterior to the
lens ? and lastly, What can be the effect of the contraction of so
important a muscular structure but to bend in the border of the
cornea, and thus increase the curvature of the object-glass of the eye ?
Its origin—the sclerotic—is unyielding ; its insertion—the cornea
—is. The liquid of the eye resists the inward pressure of the cornea,
and driving its central part out, still more increases the curvature.
Lastly, in the elastic lamina of the cornea do we not see the anta-
gonist of this powerful muscle. Birds must necessarily possess
greater power of focal accommodation than man, but why should
the mechanism by which that accommodation is obtained be so
different from that of man as the views of Helmholtz would lead
us to suppose, if we believe the ciliary muscle of birds to operate as
I have suggested ?

a

Monthly Microscopical
(P2037) Journal, Oct. 1, 1869.

NEW BOOKS, WITH SHORT NOTICES.

Recherches sur Vembryogénie des Crustacés. I. Observations sur le
développement de l Asellus aquaticus. Par Edouard Van Beneden,
1869.—Although the valuable memoir which M. Van Beneden has
been good enough to send us is not a book in the publishers’ sense
of the word, it is a work of so much importance that it justifies
our noticing it under the head of Reviews. It is the reprint of a
communication recently made to the Royal Academy of Belgium
on an interesting species of fresh-water crustacean, and it expresses
results of the highest value, especially in relation to the curious
researches of Fritz Miller and others in reference to those
Nauplius forms which have so singular a bearing on Mr. Darwin’s
views. M. Van Beneden first sketches briefly the labours of those
who have preceded him in the field, and he does so in that appre-
ciative and kindly manner which is so characteristic of the genuine
lover of scientific research.

Fritz Miller, in his ‘Fir Darwin, a book some time since
noticed in these columns, made known, under the name of larval
membrane, larvenhaut, a structureless membrane, which in the
Isopoda, and especially in Ligia, is formed round the embryo in
the first stages of its development. This cuticular layer has the
shape of an elongated sac, without lateral processes in the form of
appendages, and should be considered, says the author, not as a
dependent membrane of the ovum, but as the residue of the first
embryonic moult. Now, M. Dohrn has recognized that there is
found round the embryo of the young Asellus just such a mem-
brane as that which Fritz Miller has described in Lngia and
others. M. Sars has also observed this, and has seen its relations
to the antenna, which had escaped M. Dohrn, and which is a mor-
phological fact of great import. MM. Dohrn and Sars consider
that the egg, at the moment it passes into the incubating pouch, is
surrounded by two membranes, the outer of which represents the
chorion, and the inner of which is a vitelline membrane. M. Dohrn
has not tried to determine its significance, and he has simply termed
the inner egeg-membrane innere Hihaut.

But the author has satisfied himself that at the moment of the
ege’s passing into the incubating pouch it is surrounded by a
single membrane, which is directly applied to the vitellus. Soon,
however, this separates, and leaves between it and the vitellus a
transparent liquid. The single envelope on the recently-deposited
ovum is what is generally styled the chorion. The other or inner
membrane forms itself in the ordinary course of development after
the egg has remained for some hours in the incubating pouch.
What is the value and import of this envelope? Is it part of the
ovum, or is it rather an embryonic formation and the remnant of
an embryonic moult which precedes the Nauplius moult ?

wyournel, Oct Paes | PROGRESS OF MICROSCOPICAL SCIENCE. 209

A number of questions remain to be decided :—(1) Is the
ovum of Asellus really covered at the moment of deposition by
two envelopes, as MM. Dohrn and Sars allege? (2) What is
the morphological significance attaching to the inner membrane,
which according to M. Sars is a vitelline membrane? (3) Is
M. Dohrn correct in comparing the membrane which he calls
Larvenhaut in Asellus with the larval membrane of Ligia? It is
to the consideration of these three problems that M. Van Beneden
devotes his attention in the memoir before us. He goes into the
details of the embryology of Asellus which bear on the point;
traces out the whole early development of the species; and illus-
trates it by four plates containing several well-drawn representa-
tions of the egg and larva in different phases; and finally concludes
by laying down the following propositions :—-(1) The ovarian egg,
at the time of deposition, consists of only one membrane, the
chorion. (2) This membrane remains for some considerable period
the sole membrane of the egg. (3) The membrane, which both
MM. Sars and Dohrn associate with the ovum, is really an
embryonic membrane. (4) The study of the inferior crustacea,
and especially of Anchorelle and Lerneopods», demonstrates that
in these Lernesx the embryo undergoes three moults even while in
the egg: a Blastodermic moult, a Nauplian moult, and a Cyclopean
or Zoéan moult. That each of these moults consists in the loss of
a cuticular membrane, having the form which the embryo has at
the time the membrane is formed. The first embryonic membrane
of Asellus is a Blastodermic cuticle, and subsequently there is
formed a Nauplian cuticle which corresponds to the larval mem-
brane of Ligia. M. Van Beneden’s memoir is one which must be
carefully studied by every student of Embryology.

PROGRESS OF MICROSCOPICAL SCIENCE.

The Development of the Chetopoda.—Under this title a very valu-
able memoir has been written jointly by Professor Claparéde and
Mecznikow, in the last number of Siebold and Ko6lliker’s Zeitschrift.
It is illustrated by a great number (upwards of a hundred) beautifully-
drawn coloured figures, and traces the stages of development in the
typical members of the family of this group. Hach species selected is
dealt with separately and completely, and the whole memoir is one
of the fullest published on the subject.

The Anatomy of the Bed-bug.—The structure of Cimex lactularius
is very fully described in another paper in Siebold’s Zeitschrift by Herr
Professor Landois. This is a continuation of a paper published some
time since in this Journal by the same author. In this part Dr.
Landois treats of the respiratory, reproductive, and muscular systems.

VOL. II. Q

210 PROGRESS OF MICROSCOPICAL SCIENCE. [yo oct seo
His account is partly based on the researches of those who have
preceded him, and in great part on his own observations. The plates
accompanying this article are two in number, and are carefully drawn.
His account of the reproductive system and of the arrangement of the
muscles is particularly good, especially the latter. He describes very
minutely the attachment of the various muscles which are employed
in working the proboscis. The paper should be consulted by those
Fellows of the Royal Microscopical Society who wish to work out
this subject.—See Zeitschrift fiir Wissenschaftliche Zoologic, 19 Band.,
2 Heft, 1869.

The Oral Apparatus of Oxyuris.—Herr J. H. L. Flogel publishes a
brief but good contribution to the anatomy of the mouth of this
nematoid and its congeners. His illustrations are in some cases
merely diagrammatic, but in other cases they represent different front
and profile views of the head. The lips and their peculiar papille are
especially the subject of this paper. The author employed immersive
objectives.—Ibid. ;

The Reproduction of Siphonophora.—The number of Siebold’s journal
already referred to, and which is rich in histological matter, contains
also an interesting paper which is hardly microscopic, though nearly
so. The author, Dr. Alex. Pagenstecher, of Heidelberg, describes a
new and peculiar mode of reproduction in this ccelenterate.

Histology of the Lower Animals.—Under this title Herr -Fritz
Ratzel has commenced, in the last number of the Zeitschrift fiir Zoologie,
the first of a series of papers, which he proposes to make a histo-
logical account of all the lower animals. The present communication
deals with the muscular system of annelids; but is not at all as compre-
hensive as the memoir published on the muscular tissue of mollusks,
by Franz Boll, and which appeared in a recent supplement te Schultze’s
Archiv. We notice too that the author does not refer to the labours
of some English zoologists as he ought to do. This paper is followed
by a very short one on the muscular system of Nematoides, by Herr
Anton Schneider.

Acanthocystis Viridis——Dr. H. Grenacher makes some observations
on this species in the same number of Siebold’s Zeitschrift above
referred to.

Intermediate Forms between Worms and. Crustacea—Some years
since M. Dujardin called attention in the Annales des Sciences (1851),
to a small marine form which seemed to connect the Crustacea and
annelids. This creature Hchinoderes has been very minutely described
and figured in a memoir published by Herr Dr. Richard Greef, of
Bonn. The author gives an account of both the general morphology.
and internal anatomy of various species of the genus. The subject.
has an interest in connection with Mr. Darwin’s views.— Vide Wieg-
mann’s Archiv fiir Naturgeschichte. 1 Heft. 1 Band. 1869.

The Pollen Grains of Onagracece Cucurbitacece and Corylacee.—To
those who desire an easy and interesting subject for microscopic work,
the paper on the above subject, by Herr C. W. Luerssen, will afford

eepurhal Oc digs. | PROGRESS OF MICROSCOPICAL SCIENCE. 211

ample suggestions. The author takes up the question whether the
pollen grains of those families consist of a single cell or of more than
one. The illustrations are very numerous, and altogether the paper
shows kow much elaborate research may be carried out in so limited
a subject.—Jahrbuch fiir Wissenschaftliche Botanik, 1869.

The Natural History and Development of the Ustilaginee.—This is
a memoir, copiously illustrated and extending over 100 pages, and
fully dealing with a very extensive branch of fungology. The author
is Dr. A. Fischer von Waldheim. We wish the paper could be repro-
duced in full in our language.

The Microscopical Structure of the Conwolutions of the Brain.—The
‘Journal of Mental Science’ gives the following summary of Mr. Lock-
hart Clarke’s latest researches on this subject. The summary was, we
believe, prepared by Mr. Clarke for the recent second edition of Dr.
Maudsley’s treatise on the Physiology of the Mind.

In the human brain most of the convolutions, when properly
examined, may be seen to consist of at least seven distinct and con-
centric layers of nervous substance, which are alternately paler and
darker from the circumference to the centre. The laminated structure
is most strongly marked at the extremity of the posterior lobe. In
this situation all the nerve-cells are small, but differ considerably in
shape, and are much more abundant in some layers than in others.
In the superficial layer, which is pale, they are round, oval, fusiform,
and angular, but not numerous. The second and darker layer is
densely crowded with cells of a similar kind, in company with others
that are pyriform and pyramidal, and lie with their tapering ends
either toward the surface or parallel with it, in connection with fibres
which run in corresponding directions. The broader ends of the
pyramidal cells give off two, three, four, or more processes, which run
partly toward the central white axis of the convolution and in part
horizontally along the plane of the layer, to be continuous, like those
at the opposite ends of the cells, with nerve-fibres running in different
directions.

The third layer is of a much paler colour. It is crossed, however,
at right angles by narrow and elongated groups of small cells and
nuclei of the same general appearance as those of the preceding
layer. These groups are separated from each other by bundles of fibres
radiating toward the surface from the central white axis of the con-
volution, and, together with them, form a beautiful fanlike structure.

The fourth layer also contains elongated groups of small cells and
nuclei, radiating at right angles to its plane; but the groups are
broader, more regular, and, together with the bundles of fibres between
them, present a more distinctly fanlike arrangement.

The fifth layer is again paler and somewhat white. It contains,
however, cells and nuclei which have a general resemblance to those
of the preceding layers, but they exhibit only a faintly radiating
arrangement.

The sixth and most internal layer is reddish grey. It not only
abounds with cells like those already described, but contains others

Q 2

212 PROGRESS OF MICROSCOPICAL SCIENCE. (po Oc a aes
that are rather larger. It is only here and there that the cells are
collected into elongated groups which give the appearance of radia-
tions. On its under-side it gradually blends with the central white
axis of the convolution, into which its cells are scattered for some
distance.

The seventh layer is this central white stem or axis of the con-
volution. On every side it gives off bundles of fibres, which diverge
in all directions, and in a fanlike manner, toward the surface through
the several grey layers. As they pass between the elongated and
radiating groups of cells in the inner grey layers, some of them become
continuous with the processes of the cells in the same section or plane,
but others bend round and run horizontally, both in a transverse and
longitudinal direction (in reference to the course of the entire con-
volution), and with various degrees of obliquity. While the bundles
themselves are by this means reduced in size, their component fibres
become finer in proportion as they traverse the layers toward the
surface, in consequence, apparently, of branches which they give off to
be connected with cells in their course. Those which reach the outer
grey layer are reduced to the finest dimensions, and form a close net-
work with which the nuclei and cells are in connection.

Besides these fibres, which diverge from the central white ‘axis of
the convolution, another set, springing from the same source, converge,
or rather curve inward from opposite sides, to form arches along some
of the grey layers. These arciform fibres run in different planes—
transversely, obliquely, and longitudinally—and appear to be partly
continuous with those of the divergent set which bend round, as already
stated, to follow a similar course. All these fibres establish an
infinite number of communications in every direction between different
parts of each convolution, between different convolutions, and between
these and the central white substance.

The other convolutions of the cerebral hemispheres differ from
those at the extremities of the posterior lobes, not only by the compara-
tive faintness of their several layers, but also by the appearance of
some of their cells. We have already seen that, at the extremity of
the posterior lobe, the cells of auu the layers are small, and of nearly
uniform size, the inner layer only containing some that are a little
larger. But, on proceeding forward from this point, the convolutions
are found to contain a number of cells of a much larger kind. A
section, for instance, taken from a convolution at the vertex, contains
a number of large, triangular, oval, and pyramidal cells, scattered at
various intervals through the two inner bands of arciform fibres and
the grey layer between them, in company with a multitude of smaller
cells which differ but little from those at the extremity of the posterior
lobe. |The pyramidal cells are very peculiar. Their bases are quadran-
gular, directed toward the central white substance, and each gives
off four or more processes which run partly toward the centre, to be
continuous with fibres radiating from the central white axis, and
partly parallel with the surface of the convolution, to be continuous
with arciform fibres. The processes frequently subdivide into minute
branches, which form part of the network between them. The opposite

Monthly Microscopical] PROGRESS OF MICROSCOPICAL SCIENCE. 213

end of the cell tapers gradually into a straight process, which runs
directly toward the surface of the convolution, and may be traced to
a surprising distance, giving off minute branches in its course, and
becoming lost, like the others, in the surrounding network. Many of
these cells, as well as others of a triangular, oval, and pyriform shape,
are as large as those in the anterior grey substance of the spinal cord.

In other convolutions the vesicular structure is again somewhat
modified. Thus, in the surface convolution of the great longitudinal
fissure, on a level with the anterior extremity of the corpus callosum,
and therefore corresponding to what is called the superior frontal
convolution, all the three inner layers of grey substance are thronged
with pyramidal, triangular, and oval cells of considerable size, and in
much greater number than in the situation last mentioned. Between
these, as usual, is a multitude of nuclei and smaller cells. The inner
orbital convolution, situated on the outer side of the olfactory bulb,
contains a vast multitude of pyriform, pyramidal, and triangular cells,
arranged in very regular order, but none that are so large as many of
those found in the convolutions at the vertex. Again, in the insula,
or island of Reil, which overlies the extra-ventricular portion of the
corpus striatum, a great number of the cells are somewhat larger, and
the general aspect of the tissue is rather different. A further variety
is presented by the temporo-sphenoidal lobe, which covers the insula
and is continuous with it; for, while in the superficial and deep layers
the cells are rather small, the middle layer is crowded with pyramidal
and oval cells of considerable and rather uniform size. But not only
in different convolutions does the structure assume, to a greater or less
extent, a variety of modifications, but even different parts of the same
convolution may vary with regard either to the arrangement or the
relative size of their cells.

Between the cells of the convolutions in man and those of the ape-
tribe I could not perceive any difference whatever; but they certainly
differ in some respects from those of the larger mammalia—from
those, for instance, of the ox, sheep, or cat.

The Structure of the Human Blood-corpuscle.—As far back as May,
1868, Professor Freer, of Rush Medical College, U.S., asserted that
human blood-corpuscles were not, as heretofore supposed, simply
bi-concave discs; but that, on the contrary, there may be seen (by the
use of Wale’s illuminator) a nipple-like eminence in the centre of the
concavity of each well-formed disc. This papillary eminence is about
tosoo Of an inch in diameter at its base; consequently, he arrays
himself against the expressed opinion of physiologists and microscopic
anatomists as set forth in standard works, to wit, that the human blood
is non-nucleated. Continued investigation on this subject since the
first article was published, has confirmed the announcement then
made, and now he illustrates his discovery by two diagrams—one
representing corpuscles of human blood, the other corpuscles of a
frog—both of which exhibit these eminences. All of the research
upon which his present convictions are based has been prosecuted by
the use of reflected light instead of transmitted light, by which most
examinations of blood-corpuscles have been made heretofore. Cor-

214 PROGRESS OF MICROSCOPICAL SCIENCE. [Mythiy Mocroscapical
puscles found in defibrinated blood are, he says, the best for observa-
tion.— Vide ‘New York Medical Record,’ August 16th.

Dr. Carpenter's Deep-sea Expedition—At the meeting of the
British Association a letter was read by the Rev. A. M. Norman from
Professor Wyville Thomson on the “Successful Dredging of H.MLS.
‘Porcupine’ in 2435 fathoms.” This is nearly the height of Mont
Blanc. It must be understood that dredging is a very different thing
from sounding. ‘The first dredge brought up 14 ewt. of ooze, the
second 2 cwt., from this great depth. The bottom temperature was
30°. The sun’s heat extended downwards 20 fathoms; that of the
Gulf-stream 500 fathoms; after that the temperature sank generally
at the rate of two-tenths of a degree for every 200 fathoms. Not
only was animal life abundant at the great depth of nearly 2500
fathoms, but many new forms were added to science, and several
related to the British fauna. ‘I'he chemical condition of the water at
great depths showed that it was strongly impregnated with organic
matter, which accounted for the food provided for the animals at the
bottom of the sea. The dredging demonstrated that there were living
creatures now at the bottom of the sea precisely similar to the fossils
of the chalk.

Microscopic Examination of Obsidian—Mr. W. C. Roberts, F.C.S.,
F.G.8S., gave an account at the Exeter meeting of his application of
the microscope to the examination of specimens of obsidian from
Java. The paper was a statement of the results of the examination of
a substance that, from the indefinite character of its composition, par-
takes of the nature of a rock rather than that of a mineral. The spe-
cimen of obsidian was from Java, originally in the cabinet of Bernard
Woodward, Esq., but the label does not give the exact locality. It
appeared to differ much from that, also from Java, now in the British
Museum. The specific gravity of the specimen was 2°35; in thin
sections it is perfectly transparent. Mr. Roberts gave an analysis of
its coniposition, and said that it may be easily cut into thin sections,
and by the aid of a low power, say 200 diameters, at least three dis-
tinct minerals (beautifully crystallized) may be distinguished, dia-
grams of which were produced with the specimen.

Photographs of Nobert’s Lines.—The recently-published ‘ 'Transae-
tions of the Philadelphia Academy of Natural Science’ gives the
following account of the presentation of Drs. Curtis and Woodward’s
photographs of Nobert’s lines, and as the photographs are also in the
library of the Royal Microscopical Society, the observations may be
of interest to our readers :—“'The bands were very beautifully photo-
graphed, showing up to the sixteenth perfect lines that can be counted
through the whole width. Their instruments failing to resolve, or
rather, to photograph the four finer bands, sixteen, seventeen, eighteen,
and nineteen, Dr. Woodward infers that the last four bands have not
been resolved. Mr. Stodder remarked that in his opinion the claim
to have resolved the finer bands, advanced by Mr. Greenleaf and him-
self, was not disproved by this failure to photograph them. The

‘condition of the microscope for photographing (without an eye-piece)

Mrournal, Oct 1 1860, | PROGRESS OF MICROSCOPICAL SCIENCE. 2

is so different from its condition for vision, that he considered the
failure to photograph lines of such exceeding delicacy no proof that
the lines could not have been seen, and more than that, that the failure
of one operator to photograph with a certain instrument is not to be
accepted as a proof that another observer with another instrument and
other manipulations failed to see these lines. Mr. R. C. Greenleat
showed a specimen of Amphipleura pellucida, mounted dry, on which he
claimed to show the markings. As this has been one of the most diffi-
cult of the diatoms to resolve, and perhaps the one about the resolving of
which there has been the most dispute, Mr. Greenleaf proposed leaving
the matter open for further examination and discussion. Dr. Rufus
King Browne, of New York, being present, spoke of the difficulty of per-
fectly resolving the markings on this form; he considered the markings
as granules or tubercles, which appear as lines or puncta, according to
the light thrown upon them, and that the markings were not as fine or
close as claimed by microscopists.” ‘This observation so thoroughly
confirms the results obtained by our President (the Rev. J. B. Reade,
F.R.S.) and Mr. Wenham, that it i dogenscs attention at the present
time.

A Peculiar Minute Thread-worm infesting the Brain of the Snake-
bird (Plotus. anhinga).—Dr. Jeftries Wyman, the well-known American
physiologist, has described and figured a minute parasite of the Nema-
toid group, which he has found in great multitudes in the brain of
the Snake-bird of East Florida. ‘The parasites were in all cases
found coiled up on the back of the cerebellum, just behind the cere-
bral lobes; in one case there were so many of them that they made
*“‘a deep indentation of the cerebellum.” The female is readily distin-
guished by being much larger than the male, measures 65 milli-
métres in length, and when fully distended with eggs has a diameter
of 0°5 millimétre. The mouth is terminal, without lips or papilla,
the intestine passes in a straight direction to the opposite end of the
body, and if it opens at all does so at the point of it, though the open-
ing itself was not distinctly seen. Several loops of the oviduct are
easily observed through the integuments, and one much larger than
the rest can be seen at the hinder part of the body. The genital
pore was not found, but is probably in the middle portion of the body,
as near the two ends only loops of the oviduct are seen, and these
nowhere connected with the walls. The male is only about one-half
the linear dimensions of the female, and the hinder portion of the
body is always more closely coiled. The intestine has the same
arrangement as in the female. Near the hinder end of the body, and
on the concave side of the last half-coil, is a papilla from which in
one case we saw the male organ protruded, having the form of a
slightly recurved spine. The base of this was buried beneath the
surface, and in close relation to the end of the spermatic tube. In
almost every instance the oviducts were largely distended with ova in
different stages of development, and with hatched young. The eggs
are of an oval form, their long diameter being about 0:02 millimétre.
Those least advanced contained simply granules, and others had the
embryo roughly sketched by the arrangement of the whole mass of

216 PROGRESS OF MICROSCOPICAL SCIENCE. [oq beta tbo

granules in the form of a coiled cylinder of uniform diameter
throughout, slightly rounded at the two ends, and invested with a
thin membrane. It is while in this stage that the embryo leaves the
egg, and vast numbers of them were seen without coverings, but still
closely coiled. As they descend towards the lower part of the oviduct
they begin to straighten themselves, and at the same time undergo a
slight change of form. As the body uncoils one end enlarges, and the
whole tapers regularly towards the hinder part, and forms an ex-
tremely elongated cone. When perfectly straight they measure about
0°15 millimétre in length. Dr. Wyman was unable to detect any
internal organs, if such existed, at any stage of development observed ;
but, on the contrary, saw nothing but granules, filling the integuments
as in the first formation of the embryo.

The Development of Brachiopoda.—This subject, to which so little
attention has been paid, has been lately taken up by an American
naturalist, Mr. E. 8. Morse, who has shown by embryological observa-
tions the close relation which exists between Brachiopods and Polyzoa.
The eggs were kidney-shaped, and resembled the statoblasts of Frede-
ricella. No intermediate stages were seen between the eggs and the
pear-shaped form. This stage recalled in general proportions Megerlia
or Argiope in heing transversely oval, in having the hinge-margin wide
and straight, and in the large foramen. Between this stage and the
next the shell elongates until we have a form remarkably like Lingula,
having, like Lingula, a peduncle longer than the shell, by which it
holds fast to the rock. It suggests also in its movements the nervously
acting Pedicellina. In this and the several succeeding stages, the
mouth points directly backward (forward of author's), or away from
the peduncular end, and is surrounded by a few ciliated cirri, which
forcibly recall certain Polyzoa. The stomach and intestine ‘form a
simple chamber, alternating in their contractions, and forcing the
particles of food from one portion to the other. At this time also
the brownish appearance of the walls of the stomach resembles the
hepatic folds of the Polyzoa. Ina more advanced stage, a fold is
seen on each side of the stomach; from this fold the complicated
liver of the adult is developed, first, by a few diverticular appendages.
When the animal is about one-eighth of an inch in length, the lopho-
phore begins to assume the horseshoe-shaped form of Pectinatella and
other high Polyzoa. The mouth at this stage begins to turn towards
the dorsal valve (ventral of author’s), and as’ the central lobes of the
lophophore begin to develop, the lateral arms are deflected. In these
stages an epistome is very marked, and it was noticed that the end of
the intestine was held to the mantle by attachment, as in the adult,
reminding one of the funiculus in the Phylactolemata. No traces of
an anus were discovered, though many specimens were carefully
examined under high powers for this purpose, the intestine of the
adult being repeatedly ruptured under the compressor without show-
ing any evidence of an anal aperture—American Naturalist, Sept.

Monthly Micro ical
Seca, Oct. 1 1869. ( 217 )

NOTES AND MEMORANDA.

A New Dissecting Microscope.—We have examined an instrument
recently brought out by Mr. Chas. Collins, and which we think will be
found very useful by those who dissect
under the higher magnifying powers.
It has (as seen in figure) a tripod foot,
and a large glass stage which is mova-
ble, and can be replaced by a trough of
gutta-percha or other material. The
peculiarity of the instrument lies in
the fact that Mr. Collins has adapted
to the eye-piece a compound prism ee
which acts as erector, and at the same i.
time throws the rays from a vertical
to a horizontal position, so that the
head need not be stooped. We had
thought that such an arrangement i eS Sea
would have absorbed too much light, ===]
but we found dissection under the a _
inch and two-inch extremity easy and
comfortable,

The Rules of the Royal Microscopical Society.—In answer to
N. N., we may mention that the Society has a very large collection
of objects and microscopes, and an excellent library. Lectures are
not delivered, but papers are read and published, as N. N. may see in
this Journal. Our correspondent should communicate (giving his
real name and address) with one of the Secretaries.

Mr. Ross’s New Immersion Lenses.—Mr. Ross has just prepared
a number of immersion lenses, which our readers will do well to
examine. The working powers of the ~,th appear excellent. There
is a decided improvement over the dry glass in definition, and there
is vastly more light. It must be remarked, however, that this new
immersion lens is not a cheap objective like any of those made by
Nachet, Hartnack, or Merz. The cost of labour in these countries
prevents the possibility of producing a cheap first-class immersion
object-glass.

Meteorites under the Microscope.— Herr T'schermak and others on —
the Continent are investigating the structure of meteorites under the

microscope. This is a new field for some of our workers in the Royal
Microscopical Society.

Protoplasm, Life Force, and Matter.—Under this title a new
work by Dr. Beale is announced to appear this month.

How to Work with the Microscope.—A fourth edition of Dr.
Beale’s book is, we believe, issued.

New Dissecting Microscope.

' Monthly Mi ical
218 NOTES AND MEMORANDA. orm Geta Ee

Country ‘‘Fellows” of the R.M.S.—A correspondent asks why
country Fellows, who are seldom able to attend the meetings, and to
whom the library: offers little advantage, should have to pay the same
entrance fee and subscription as town “Fellows?” The question is
one for the Council to answer.

Plumules of Moths.—-We hope to give the second part of Mr.
Watson’s paper, with illustrations, in our next Number.

A Handbook of British Fungi, which will include all known
species, and will therefore deal with an important branch of micro-
scopic research, is in preparation by Mr. M. C. Cooke, the well-known
fungologist and foreign secretary to the Quekett Club. It will form
one volume, small octavo, and will contain full descriptions of all
known species of British fungi, with illustrations of the principal
genera, and references to figures of the species. The price will be
half-a-guinea to subscribers. The publication will be commenced as
soon as the names of sufficient subscribers have been received to war-
rant the undertaking. Communications should be addressed to Mr.
M. C. Cooke, 2, Junction Villas, Upper Holloway, London, N.

Mr. Collins’s Portable Microscope.—Mr. Collins has constructed
a portable microscope which is especially intended for those who pur-
chase some of his larger instru-
ments. When packed it forms
an oblong mahogany box, about
6 inches long by 3 inches wide,
and 24 high. It may easily
be carried in the great-coat
pocket. It is difficult to ex-
plain its construction, which is
partly shown in the adjacent
figure. The microscope body
is attached to the inner side of
the cover of the case. This
cover, on being lifted up, is
made to rotate on a central
pivot, so that its inside is
loosened out. The degree of
slope is obtained by an oblique
bar, which slides in a second one, and which supports the lid and can
be clamped at any angle. The stage is small, and the mirror draws
out from beneath it. The objectives and eye-piece are those of this
maker’s other instruments. We have done some work with this in-
strument, and found it very handy, in the absence of our larger micro-
scope.

A New Manipulator, by J. Howard Hooper.— There can be
few microscopists who have not longed for some more ready and
exact method of manipulation under the compound microscope than
is afforded by even the steadiest and most practised hand; and
several instruments more or less complex have been devised and
even patented for this purpose, but all have been constructed on the

Collins’s Portable Microscope.

Pee Oe is NOTES AND MEMORANDA. 219

plan of a movable tool. A little consideration will, however, show
that to keep the point worked with in view it must be perfectly steady
in the field of the objective, and, further, that in the stage and body
movements of the modern microscope we have a most perfect appa-
ratus for executing any kind of work by substituting motion of the
object for that of the tool. This principle once adopted, it becomes
comparatively easy to adapt instruments to the kind of work required,
and I append descriptions of those I have myself employed, less that
I regard them as the best practicable arrangement, than that, being
easily constructed by any one at the cost of a few pence, they serve as
a ready means of ascertaining the practical value of the system.

To the arm, or any flat part of the microscope between the coarse
and fine adjustments, attach a stiff, square plate of metal, about
14 inch diagonally, by two binding screws working through slits in
opposite corners, so as to permit the plate a horizontal motion of
about ith of an inch. To this plate is soldered vertically a stout
steel spring clip, readily made as follows :—Procure one of Lund’s
patent paper clips, sold by most stationers ; heat it red hot, to destroy
the temper ; then, with a stout pair of scissors, cut the slit to the
width of about 4th of an inch, and retemper the tube.

Select some glass tube of a size to slide rather stiffly in this clip,
draw it out at one end to about 4th of an inch thickness, bend the
thin part at an angle of 45°, and draw out so as to keep it at this
thickness for half-an-inch, or rather more, and cut it off. Three or
four of such tubes will be useful. Next take a common vaccine tube
and draw it out in a spirit-lamp to the finest possible point.

Place one of the prepared tubes in the clip, first attaching this to
the microscope, and set it so that the angular part of the tube points
as nearly as you can guess to the field of the objective you intend to
use. Measure as accurately as you can the distance of this end from
the centre of the field, and having found it, measure the same distance
on the vaccine tube from the fine end. At the point thus found apply
a little sealing-wax round the vaccine tube, and having moderately
heated the thin end of the other tube, insert the vaccine tube into it,
when it will quickly become fixed in any position desired. When the
tube is replaced in the clip, the point of the vaccine tube should admit
of being brought into the centre of the field of the objective used. If
it should not do so, the sealing-wax may be reheated, and the vaccine
tube shifted as required. Minor corrections may be made by the
sliding motion of the clip-holder.

You will thus have fixed in the field, and moving with it, a mani-
pulator far more delicate and elastic than any needle or hair. How-
ever, either needle or hair may be used in the same way if desired.
For dissection. a thick needle beaten while red hot to a spatula end,
well retempered, and ground to a very fine edge, will be a good form
of knife.

It would be easy to adapt a forceps arrangement, if desired; but
for most purposes the syringe I am about to describe will be preferable.
The body of the syringe is constructed exactly as the manipulator
above described, except that the point of the vaccine tube is broken

220 PROCEEDINGS OF SOCIETIES. TS oe
off so as to leave a tubular opening of the required fineness. The
piston consists of a moderately fine screw, firmly inserted below into
a sound cork shaped to fit the tube, and passing above through a cir-
cular nut working in aring. This ring has soldered to it below a bit
of metal tube large enough to let the screw pass freely through it, and
fitting loosely into the upper end of the glass tube, to which it may be
attached by sealing-wax in exactly the same way as the vaccine tube
is to the other end. On turning the nut the piston will be raised or
lowered as required. The syringe must be filled completely with
water before use ; it will then act with the utmost precision and deli-
cacy. Any object selected is brought to the mouth by the stage move-
ments, and on turning the nut is instantly sucked up, and can be as
readily deposited wherever required. Where two needles are desired
the second should be attached to the stage in the same way as the
stage forceps.

PROCEEDINGS OF SOCIETIES.*

Royaut MicroscopioAL Soorery.

Kine’s CoLuLece, September 22, 1869.
The Society will hold its first meeting of the session on Wednes-
day evening, the 13th of October, at 8 p.m., when the following papers
will be read :—“ On Immersion Objectives and Nobert’s Test-Plate,”
by Lieut.-Col. Woodward, U.S. army; “On High-power Definition,
with illustrative examples,” by G. W. Royston Pigott, M.D., F.R.A.S.;
and Mr. Carruthers will give (vivé voce) a communication “On Plants

of the Coal-measures.”
Watter W. Reeves,
Assist, Secretary.

QuEKETT MicroscopicaL CLUB.T

At the ordinary meeting, held at University College, Aug. 27, 1869,
Dr. R. Braithwaite, F.L.S., Vice-President, in the chair, three new
members were elected. Several donations to the club were announced,
and four gentlemen were proposed for membership. A paper by Mr.
G. W. Hart, “On Oysters and Oyster Spat,” was read by the secretary,
in which the growth and development of the embryo oyster was de-
scribed at length, and a number of interesting questions as to the
mode of fertilization and reproduction were brought forward. The
paper was illustrated by diagrams. Mr. B. T. Lowne made some ob-
servations upon the subject of the fertilization of the oyster spat,

* Secretaries of Societies will greatly oblige us by writing out their reports
legibly—especially the technical terms—and by “underlining” words, such as
specific names, which must be printed in italics. They will thus ensure accuracy
and enhance the value of their proceedings.—Ep., M. M. J.

+ Report supplied by Mr. R. T. Lewis.

eee Od vie PROCEEDINGS OF SOCIETIES. 2k

thinking that whilst it was probable that these creatures were her-
maphrodite, and capable of self-fecundation, yet it seemed also
probable from analogy that the spermatozoa of other individuals would
be prepotent, and that, as in plants, crossing was most likely to cause
great improvement in the breed. Mr. W. Hislop read a paper “ Ona
New Analyzing Selenite Stage,” the subject being illustrated by
diagrams and by the apparatus described. A paper was also read by
Dr. John Matthews “On a New and Simple Mode of Micrometry.”
This ingenious contrivance consisted in having two adjustable points
of steel fitted to the eye-piece in such a way that they could be made
to move across the field of view, and measure the diameters of objects
in the same way as a pair of callipers, the value of such measurements
being afterwards ascertained by removing the object and substituting a
stage micrometer. Several important advantages were claimed for
this instrument, which was exhibited in the room, and attracted much
attention. Mr. H. F. Hailes drew attention to some specimens of a
new form of porcelain shade for microscope lamps, which he had
made the subject of a paper in February last; the articles were now
ready for delivery by Mr. Baker, of High Holborn. Mr. W. Hislop
also mentioned that a new 34-in. objective, by Mr. Smith, jun., was
being exhibited in the room, and he made a few observations upon the
desirability of ascertaining the temperatures at which micro-crystals
were formed, and introduced to the notice of the members a new ther-
mometer, which had been constructed for him by Mr. Hill for this
purpose. Cordial votes of thanks to the readers of the papers were
carried unanimously. The chairman announced the meetings and
field excursions for the ensuing month, and the proceedings terminated
with a conversazione, at which a number of very interesting objects
were exhibited.

BriIGHTON AND Sussex Naturat History Society.

Sept. 9th.—Annual meeting, at which the Committee’s report for
the year was presented, and the officers for the ensuing year elected.
President—Mr. T. H. Hennah. Committee—Messrs. G. W. Sawyer
Noakes, J. Dennant, R. Glaisyer, and the Revs. J. H. Cross and J.
Image. Treasurer—Mr. T. B. Horne. Hon. Secs——Mr. T. W.
Wonfor and J. Colbatch Onions. Hon. Librarian—Mr. Gwatkin.
After which the ordinary meeting was held (a microscopical one), at
which Mr. T. Hennah exhibited living beetle, showing structure of
mouth, and Marchantia polymorpha in fruit and elaters of same; Mr.
Smith exhibited fructification of Hepatic; Mr. Glaisyer exhibited
Sphagnum squamosum, with porous cells and spiral fibres; Mr.
Gwatkin exhibited skin of toad, Fossil wood from Great Desert, lung
of boa constrictor, and large intestine of ostrich ; Dr. Hallifax, section
of lady-bird, showing optic and ventral ganglia; ditto of bee, showing
tongue and suctorial apparatus; ditto of common fly, showing pro-
boscis and eggs of parasites of Bohemian pheasant and Mallee bird ;
Mr. T. Cooper exhibited sections of yew, &c., embryo oysters, and
Polycistina; Mr. R. Glaisyer exhibited sections of crab-shell, prima

22, PROCEEDINGS OF SOCIETIES. MSE CeCe
and mitra shells, and Australian foraminifera ; Mr. Davidson showed
foraminifere from Nice; Mr. Wonfor exhibited Pleurosigma formosum
and P. angulatum with a Reade’s prism, injected preparation of Dr.
Thudichum’s Trichinous rabbit, and a series of the South American
pest Pulex penetrans, chigoe or jigger, kindly lent by Mr. T. Curties,
of Holborn. There were also exhibited by Mr. Baker, of London,
Wright’s and other collecting bottles, lamp chimneys to give white
cloud light, Reade’s prisms, and other apparatus. =

MicroscopicaAL Soorety oF LIveERPoouL.

The seventh ordinary meeting was held at the Royal Institution
on Tuesday, 6th July. The President, Dr. Nevins, in the chair. A
paper was read by the Rev. W. H. Dallinger, on ‘Spontaneous Gene-
ration.” The author said that the present position of science was
attributable solely to its stern adhesion to truth. It admitted no
inference that was not firmly based on fact, and suffered no generali-
zation but such as accumulated fact rendered almost axiomatic; but,
although the leading minds of science were in harmony with its prin-
ciples, they were sometimes led to generalization upon hypothetical
“facts.” To a mind cultured to scientific thought, and trained to
scientific induction, nothing was more incongruous than that certain
biological phenomena—call them electric, or magnetic, or mesmeric,
or what you will—because they are beyond the reach of immediate
interpretation, should be hastily generalized into the supernatural, and
branded with the name of “spiritualism.” Now, the powers and pcr-
fection of the microscope have recently been gr eatly augmented The
consequence of this is that the lower organisms and minute vital
developments of nature have been subjected to the strictest scrutiny.
With powers magnifying variously from 200 to 15,000 or 20,000 dia-
meters, earnest and enthusiastic minds have challenged nature for the
mystery of life, and strange facts have come to us. But these “facts”
are many of them incongruous and conflicting, and the correlations
of many more are entirely hidden. Nevertheless they appear to some
thinkers to point in an anticipated direction, and, strangely enough,
some few of the very master minds of science have committed them-
selves to a generalization in a name, and called the phenomena “ spon-
taneous generation.” Mr. Dallinger said he was not anxious to deny
or to defend the theory; all he asked was stern fact, and not hypo-
thesis from which to infer. As a minister of the Gospel, he had no
fear of “spontaneous generation,” provided it could be shown to be a
correct interpretation of the facts of nature; but that it should be
this he respectfully contended. The two antagonistic theories of
life—the one that it was simply a correlative of the forces of nature,
making life “not independent of matter, but a condition of it,” and
declaring “that there is no boundary line between organic and inor-
ganic substances ;” the other, that it was a force distinct from matter
and independent of it, called “vital force ”—were carefully explained
and illustrated by quotation. The question, it would appear, could

* Report supplied by Mr. T. W. Wonfor.

Nyournal, Oct 1 808 PROCEEDINGS OF SOCIETIES. 223

only be settled by a careful examination of the lowest and minutest
forms of life. Now, it was well known that if an “infusion” of animal
or vegetable matter were placed in, say a glass vessel, and left for
some hours, it teemed with life in its lowest forms—molecules, bac-
teria, vibrios, and even ciliated animalcula. Nor was an “infusion”’
necessary. Water taken from a shower of rain after drought was
equally efficient. What, then, is the origin of these? Do they result
from some physical force, uniting the fortuitous particles in the water ?
or are the ova of these living forms—immeasurably minute—floating
in the air, deposited in the water, the element of their development
and life? To answer this question in a scientific way it was evi-
dently essential that we should be absolutely certain that’ the water
does not contain the germs of these vital forms. To say that they
are not seen when the infusion is first made, is—even if the asser-
tion be granted—only to suggest that your powers of research are
not equal to this discovery. There must be, not assumption, but
certainty. This might be done by producing the water syntheti-
cally from its pure element. This the author carefully did by
reducing the black oxide of copper with hydrogen, procuring about
a wine-glass of water. This was divided into three parts. One
part was placed in an exhausted flask, and the ingress of air pre-
vented. Another third was placed in a U-shaped tube, and the
open ends plugged with cotton wool, thus causing the air to be
‘* wiped’ in its passage to the water. The third part was freely ex-
posed. In five days the exposed vessel teemed with bacteria and
-vibrios. In eight days the water in the plugged tubes was searched
and was almost entirely void of life. In twelve days that in the flask
was carefully examined with the ;,-inch and ;},-inch objectives of
Powell and Lealand, and absolutely nothing was discovered. This
was repeated with the same results. But in this instance the flask,
at first exhausted of air, was next supplied with air of which the
elements (oxygen and nitrogen) had been carefully produced in
the laboratory. But no life resulted. The same water was then
freely exposed to the air, and in four days abundance of bacteria
were found. Infusions of hay were then used: some vessels, con-
taining portions of the same infusion, being exposed to an artificial
atmosphere, others to the natural. Life was found in both alike, only
apparently in greater abundance in the former. Hence, then, the
ova did not come from the air alone, if at all. Therefore if the
germinal forms existed they must have existed in the infusion.

After a few remarks from the President, the meeting concluded
with the usual conversazione.

Monthly Microscopical
( 224 ) Tenenelt Oct. 1, 1869.

BIBLIOGRAPHY.

Beitrage zur Kenntniss der in den Soolwassern von Kreuznach
lebenden Diatomeen von Dr. Leopold Dippel. Kreuznach: Voigt-
lander.

Die Bulbi der Placentar-Arterien von Prof. Dr. Joseph Hyrtl.
Wien: Gerold’s Sohn.

Archiv fiir Naturgeschichte, Gegrundet von 8. F. A. Wiegmann.
35 Jahrgang. Berlin: Nicolai.

Note sur les Lichens de Port Natal ; par M. W. Nylander. Caen:
Blanc-Hardel.

Nouvelles Observations sur la Puceron de la Vigne (Phylloxera
vastatrix) ; par M. J. E. Planchet. Montpellier: Grollier.

Recherches d’Anatomie comparée; par M. HE. Baudelot. Stras-
bourg : Silbermann.

Ueber miachtige Gebirgsschichten vorherrschend aus mikrosko-
pischen Bacillarien unter und bei der Stadt Mexico. Von Dr. C.
Ehrenberg. Berlin: Diimmlers Verlags Buchhandlung.

Anatomie et Physiologie des Organes reproducteurs des Cham-
pignons et des Lichens; par M. le docteur H. Bocquillon. Paris:
Martinet.

Considérations Théoriques et Pratiques sur l’Oidium et sur la
nouvelle Maladie de la Vigne; par M. le docteur Baubil. Bordeaux :
Dupuy.

Observations générales sur les Causes de la Maladie des Vers-a-
soie; par M. Gagnat de Joyeuse. Lyon: Pitrat.

De la Reproduction des Animaux infusoires; par M. le docteur
Léon Marchand. Paris: Savy.

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Olodendron minus, Lu7dl. & Hum

THE

MONTHLY MICROSCOPICAL JOURNAL.

NOVEMBER 1, 1869.

I.—On the Structure of the Stems of the Arborescent Lycopo-
diacex of the Coal-Measures (Ulodendron minus, Lindl. and
Hutt). By Wu. Carrvtuers, F.L.S., F.G.8., Botanical Depart-
ment, British Museum.

PLATE XXXI,

Tre genus Ulodendron was established by Lindley in the “ Fossil
Flora” for a group of Lepidodendroid stems, which, besides the
rhomboidal leaf scars arranged spirally on the stem as in Lepido-
dendron, had deep oval or circular cavities ranged in two vertical
rows on opposite sides of the trunk. Several species have been
recorded, all of them-from the Coal-measures. Professor Morris,
in the last edition of his Catalogue of British Fossils, gives the
names of seven species; but some of these must be reduced to
synonyms. Belonging to the same group are two other forms
which have received generic designations, but which should be
placed, I believe, in this genus. ‘These are Megaphyton and
Bothrodendron: the only character which distinguishes the latter
genus from Ulodendron is the obliquely oval form of the vertical
scars. Megaphyton is based upon amorphous casts of a portion of
the interior of the stem of Ulodendron. ‘The series of scars repre-
sent the cavities, through which the vascular bundles to the vertical
appendages passed, as they existed on the inner surface of the

EXPLANATION OF PLATE XXXI.

Fic. 1.—Transverse section of a little more than half of the flattened stem of
Ulodendron minus, Lindl. and Hutt., showing the scalariform axis—
natural size.

2.—Transverse section of a portion of the axis. a. the large irregularly-
arranged scalariform vessels of the interior. 06. the smaller radiating
scalariform vessels of the investing cylinder. The tissues have been
destroyed in the light-coloured portions, and the space filled in with
carbonate of lime.

», 93.—Longitudinal section of the same, Icttered as in Fig. 2.

» 4.—Longitudinal tangential section, showing the openings between the vas-

cular bundles.

VOL. Ii. R

9

226 Lycopodiacee of Coal-measwres, [Monthly Microscopical

layer of elongated cells corresponding to that in Lepidodendron
selaginoides, marked e in Figs. 1 and 2 of Plate XX VII.

The specimens of Ulodendron are most frequently casts in sand-
stone of the outer surface of the stem, or amorphous casts of the
interior formed in the cavity left in the rock after the more or less
complete decay of the original organism. Impressions of the scars
oe enous seen on the surface of the lamine in bituminous
shales.

The specimen figured on Plate XXXI. is in the collection of
the late Robert Brown, now in the Botanical Department of the
British Museum. It has the label, “ Coal Measures—Hemsford or
Bradford—Rev. R. B. Cook, F.G.S., Doncaster.” It is a fragment
measuring 74 inches in length, 5 inches in breadth, and 14 inch
in thickness. The surface is covered with the carbonized remains
of the scale-like leaves arranged ina quincuncial manner. It is very
much flattened, and exhibits three round conical pits characteristic
of the species on each of its two edges. About two-thirds of the
transverse section is shown at Fig. 1 of the natural size. The
greater portion of the interior is composed of amorphous shale, but
the tissues of the centre are more or less perfectly preserved. This
forms a well-defined cylinder y>ths of an inch thick in diameter.
It corresponds to the axis and surrounding cylinder of vascular
tissue in Lepidodendron selaginoides, Sternb. (Plate XXVIL.,
Figs. 1 and 2, a and 6), and consists of similar tissues.

The transverse section (Fig. 1) shows that the inner portion is
somewhat decayed; the cavities have been filled in with white
crystallized corbonate of lime. Sufficient of the original tissue, how-
ever, remains to show clearly what it was. In the enlarged portion
(Fig. 2 a) it is seen to be composed of vessels of different sizes,
and of a circular or polyhedral form in transverse section. They
do not appear to be arranged as I have described them in Lepido-
dendron selaginoides. ‘The larger vessels are found in the interior,
and amongst them a number of smaller vessels are irregularly inter-
mixed. Towards the circumference the vessels are uniformly
smaller, but they do not alter their form, being as nearly circular
as those of the interior. In longitudinal section (Fig. 3a) they
are seen to be scalariform vessels. Their apparent shortness in the
drawing arises from the direction of the section exhibiting a some-
what oblique cut through the vessel, and not from their actual
terminations being seen.

The axis is surrounded by a cylinder of radiating scalariform
tissue (Figs. 2 and 3b). At its inner margin the diameter of the
vessels composing it are small—their size increases outwards. I
have not been able to detect any structure in this cylinder besides
the scalariform vessels. The radiating lines are frequently separated
by portions of calcite containing no organic structure. None of

hiy Mi i uf
ge Moe eo Histology of the Hye. DOT.

these spaces occur in the portion enlarged at Fig. 2b, which was
accurately drawn with the aid of the camera lucida. In the longi-
tudinal section (Fig. 4), made at right angles to the radius, several
of these openings are shown. There is an apparent approach at
regularity in their arrangement, which induces me to suppose that
they may be the openings through which the vascular bundles
passed to the leaves. They may, however, be only cracks produced
in the desiccation of the tissues.

Beyond this cylinder no structure is preserved, until we reach
the surface of the stem with the impressions of the leaves and the
series of larger scars. The parts preserved agree so nearly in re-
gard to the nature and arrangement of the tissues with what I have
described in Lepidodendron selaginordes (Sternb.), that there can-
not be any doubt as to the close affinities of these two stems. The
structureless space represents the portion occupied with the delicate
parenchyma, the more thickened and larger parenchyma beyond,
and the elongated cells of the outer portion, together with the true
bark. The proportion between the scalariform cylinder and axis
and the external layers of parenchyma is the same in both stems.
In the Lepidodendron selaginordes, figured on Plate XXVII. in
the October number of this Journal, the cylinder measures $th of
an inch, and the whole stem is an inch in diameter, while in the
Ulodendron minus, figured on Plate XX XI., the scalariform struc-
tures are #ths of an inch in diameter, and the stem in its original
eylindrical form measured 4 inches. The proportion of the axis in
both is 4th of the whole stem.

Il.—The Histology of the Eye. By Joun Warraxer Hvtxz,
F.RBS., F.R.C.8., Assistant-Surgeon to the Middlesex Hospital,
and Surgeon to the Royal London Ophthalmic Hospital.

THE eye is a microcosm—a very compendium of all the tissues.
True cell-tissues, connective tissue in several forms, muscular,
vascular, and nervous tissue, are all represented here; and there
is not another part of the whole human body which offers such
facilities for direct clinical observation, and for the anatomical
investigation of the minute tissue-changes produced by disease.

Cornea.—The cornea is composed of three distinct structures :
an outer or conjunctival layer, which, at the circumference, passes
into the loose conjunctiva covering the sclerotic; a middle layer,
the proper or lamellated cornea, which is uninterruptedly con-
tinued into the sclerotic; and a very delicate znner layer, having
complex peripheral relations with the sclerotic, ciliary muscle,
and iris.

R 2

} M
ane Histology of the Eye. (“suum werent

The conjunctival layer consists of an epitheliwm, underlaid by a
homogeneous stratum, known as “ Bowman’s membrane,” or the
“anterior elastic lamina.”

The epithelium is composed of four or five superposed rows of
cells, the aggregate thickness of which averages z4oth of an inch.
The deepest cells are subcolumnar. Their inner ends are straight,
and they rest directly on Bowman’s membrane. Their outer ends
are convex; and they form generally a crenated line, which inter-
locks with the cells immediately external to it. These intermediate
cells have a jagged inner border, and a convex outer contour. The
outermost cells are large flat scales.

The structural and chemical distinctions which so sharply
separate the horny from the mucous stratum of the epidermis are
wholly absent from this epithelium, all the cells of which, the
outermost as also the deepest, are nucleated, and are capable of
manifesting every endowment of cell-life proper to them; and this
alone would be enough to throw great doubt on the commonly
assumed parallelism between the manner of the renewal of the
corneal epithelium and that of the epidermis. The common idea,
that the deepest epithelial cells constitute a sort of matrix, from
which there is a constant progression of nascent cells towards the
outer surface to replace the loss by exfoliation, has been lately
challenged by Dr. Cleland, who, from a study of the corneal epi-
thelium in the ox, concludes that not merely the external waste,
but also the internal decay of the deepest cells, is made good by
new cells evolved out of those of the middle tier. My own ob-
servations lead me to believe that an outward progression of cells
from the innermost tier really does take place, but that all the
superficial cells are not directly referable to this source, since
proofs of cell-multiplication are met with at every depth in the
epithelium.

But the formative energy may take another direction, and
produce from the epithelium a progeny unlike the parent. Wounds
and ulcers, again, afford us abundant illustrations of this perversion.
Around these we find the epithelial cells enlarging; their nuclei,
or masses of germinal matter, dividing and subdividing until the
parent cell is filled with a brood which we cannot optically dis-
tinguish from the corpuscles of granulation, or lymph, or pus, and
which, when set free by the deliquescence of the parent capsule, we
recognize as the formed elementary constituents of granulation-
tissue, of lymph, or of pus. (Hig. 1.)

Bowman's Membrane: Anterior Elastic Lamina.—Beneath
the anterior epithelium, between it and the lamellated cornea,
is the structureless stratum first particularly described by Mr.
Bowman, and named by him the anterior elastic lamina. In
several early human foetal eyes I found that this stratum was

hly Mi 0
rome Histology of the Eye. 299

not yet differentiated; but at full term it igs very distinct.
In the adult cornea, in which its average thickness is about
tsooth of an inch, it is always remarkably conspicuous by its
transparent structurelessness,
which marks it off from the
epithelium in front and the
Jamellated corneal tissue be-
hind it. The front of the
lamina bearing the epithe-
lium is perfectly even; while
the posterior surfaceis slightly
irregular, owing to the pro-
duction of fibres which pass
slantingly from it into the
lamellated tissue, and tie the
lamina to this so closely that
it is inseparable from it by
dissection, except in very
minute pieces. These te-
fibres, originally described by “aig ee ar VE fa >
Mr. Bowman, are, I believe \@ 3 (iz)? % 4, Woe PAK \
with him, of the same nature |
as the lamina—a modified
connective substance ; and
they are perfectly distinct
from the nerve-fibres, the ; uf
tracks of which a recent | Seoumnon of Anterior Corneal Epithelium.
author supposes them to be.

The peripheral relations of the anterigr elastic lamina are very
simple. It becomes suddenly thinned at a short distance in front
of the foremost conjunctival vessels, and thence runs backwards
over the loose submucous tissue as the basement-membrane of the
conjunctiva bulbi.

The next structure is the lamellated cornea, one of the group
of connective substances. It is mainly composed of two elementary
tissues—one cellular, the other a modification of common connective
or white fibrous tissue. Their microscopic characters and the pro-
portions in which they occur are not the same at all ages. At its
first appearance, the cornea, embryology teaches, is purely a cell-
tissue; and, in the earliest human foetal cornea which I have
examined (at the fourth month), the cell or corpuscular tissue has
greatly preponderated. At full term, the disproportion is less: the
cells have still simple shapes; but they are separated by a larger
quantity of interstitial tissue, which is very distinctly fibrillated.
In the adult’s cornea, the fibrous tissue dominates ; and the cor-
puscles are large-branched cells, cohering in nets of variable sizes,

Fic. 1.

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Monthly Microscopi
230 Histology of the Eye. (Urotmal, Nov: 1, 1809.

but never co-extensive with more than a very small fraction of the
entire corneal area. (Tig. 2.)

Fic. 2.

Vertical Section of the Cornea.

The cell-nets extend in planes which intersect one another at
every possible angle, preserving always more or less parallelism to
the corneal surfaces.

Corpuscles lying in the same plane intercommunicate very
freely through their branches, and less freely with those in the
neighbouring more superficial and deeper planes; and in this way
they collectively form a system of plasmatic canals, which pervades
the entire cornea.

The interstiteal fibrous tissue consists of broad flat lamelliform
bundles, interwoven with the cell-nets, necessarily also in planes more
or less parallel to the corneal surfaces—an arrangement of the
tissues which gives the quasi-laminated appearance observable in
vertical sections of the cornea. In the foetus, the fibrillation of the
bundles is very distinct ; and in the adult it is also evident.

Blood-vessels are entirely absent from the healthy adult cornea,
the nutrition of which is wholly carried on by the corpuscular
system, which draws its plasma from the vessels of the sclerotic and
conjunctiva. Its nerves, however, are numerous. The distribution
of the coarser bundles is easily demonstrable. They enter the
circumference of the cornea, and converge towards its centre,
repeatedly dividing and uniting in a plexus, most of the bundles of
which tend towards the anterior surface. Near here they recom-
bine in a plexus of very fine bundles, from which minute branches
are detached towards the anterior elastic lamina, which they per-
forate, and reach the anterior epithelium. (Vig. 3.) The exact
relation of the nerve-fibres to the epithelium is so delicate a subject .
of inquiry, that it cannot surprise us that different opinions have

eli ea rer Histology of the Eye. 231

been arrived at respecting its nature. ‘The passage of the perfo-
rating nerve-fibres quite through the epithelium, and their free
termination at the outer surface of this, described by one observer

Fig. 3.

Corneal Nerves perforating the Anterior Elastic Lamina.

(Cohnheim), requires, I think, confirmation. I have not myself
succeeded in tracing these fibres beyond the middle tier of epithelial
cells; nor have I yet been able to demonstrate their ultimate
distribution.

The only remaining corneal tissue is the delicate membrane
which lines the posterior surface of the lamellated tissue, called
after Démours and Décémet, and sometimes also named the posterior
elastic lamina. Its thickness is only about one-third of that of
the anterior elastic lamina. It is perfectly homogeneous, without
the slightest trace of structure. It is separable from the lamellated
tissue by careful dissection in pieces of large size.

A single layer of delicate pavement-epithelium lines the inner
surface of the lamina. Its cells poliferate in some forms of
keratitis, and produce minute opaque dots upon the back of the
cornea, recognizable when illuminated by an oblique pencil of

light.

Deo Histology of the Eye. MONEE ee ea

Vitreous Humour.—This, in a perfectly healthy state, is a clear,
colourless mass of gelatinous consistence, enclosed in a_hyaloid
membranous capsule.

In the adult, the traces of structure perceptible in it are scanty
and indistinct, conveying a very impertect idea of its anatomical
composition; but in the fetus its formed elementary parts are
recognizable without difficulty, and their combinations are easily
made out; so that we naturally turn to embryology for aid; and
this, as in so many other instances, explains points in the anatomy
of the adult organ which would otherwise remain unintelligible.

Genetically, the corpus vitreum is an extension of the deeper
stratum of the cutis, intruded into the secondary eye-vesicle between
the lens and the nervous lamina which becomes the retina.

In order to make this quite clear, I must ask your attention to
some matters in the development of the eye.

The first trace of the eye in the chick, which makes its appear-
ance very early, is a hollow protrusion from the front and lateral
part of the foremost cerebral vesicle. Gradually, as this cerebral
vesicle enlarges forwards, and divides into the two segments which
Von Baer called the Vordernhirn and the Zwischenhirn, the
primary eye-vesicle shifts its place backwards and downwards until —
at length it lies beneath the Zwischenhirn ; there it becomes pedun-
culated. ‘The stalk—the future optic nerve—at first is hollow, and
through it the cavity of the eye-vesicle communicates freely with
the cerebral ventricle. |

The upper side of the eye-vesicle, where the stalk is placed, is
towards the Zwischenhirn ; whilst its opposite side is towards the
external tegument, which here consists of the epidermal stratum
only, as Remak thought, or which includes, as Kolliker believes, a
part of the cutis. At this spot the epidermis thickens; and an
anbud of it, pressing on the summit of the primary eye-vesicle,
pushes this inwards, so changing the globular shape of the vesicle
into a cup consisting of an inner and an outer plate, separated by
an interspace, the remnant of the original cavity of the first vesicle,
which continues for some time longer to communicate with the
brain-ventricle through the still hollow eye-stalk.

The cup thus formed, distinguished as the secondary eye-vesicle,
is incomplete below ; and through this gap—the foetal cleft—the
deeper stratum of the cutis intrudes between the epidermal inbud,
which is the matrix of the lens, and the anterior plate of the
secondary eye-vesicle, which is the foundation of the retina.

It will be perceived that this intruded portion of cutis fills the
space in the secondary eye-vesicle which corresponds to that in
the completed eye occupied by the vitreous humour. So long as the
foetal cleft remains open, the intruded portion of cutis (which we
may now call the vitreous humour) is directly continuous through —

Monthly Mi ical 0
Nee 1 dae Histology of the Hye. Joa

it with the exterior cutis, and nutrient blood-vessels enter the
vitreous humour through this channel. Ata later stage, the foetal
cleft closes, which perfectly isolates the internal corpus vitreum
from the external cutis. Von Ammon says that the closure of the
foetal cleft begins at its middle, and proceeds hence in both direc-
tions, forwards and backwards.

Simultaneously with the transformation of the primary eye-
vesicle into the secondary, the hollow eye-stalk became solid by the
approximation of the upper and lower plates, and acquired the form
of a flat ribbon. Next, by the inbending of its edges, the ribbon
became a gutter, along which the blood-vessels gained the inside of
the eye; and, lastly, the gutter, closing in the eye-stalk, takes the
cylindrical form of the perfect optic nerve, and includes the blood-
vessels within it.

Our knowledge of the distribution of these vessels is still very
imperfect. Von Ammon, whose articles in the ‘Archiv fir Oph-
thalmolgie’ are a fund of information on the embryology of the
eye, says that the arteria centralis, immediately on entering the
globe, gives off fine twigs to the sclerotic and choroid ; next it de-
taches several lateral branches to the retina, upon the inner surface
of which they spread out and form the membrana vasculosa feetalis
retine ; then it sends off a second set of lateral branches, from five
to seven in number, which ramify on the outer surface of the
hyaloid capsule, forming here the discus arteriosus hyaloideus ;
and, finally, the diminished trunk, traversing a canal in the vitreous
humour, is distributed to the vascular capsule of the lens. Thus
Von Ammon describes two vascular nets—one retinal, the other
belonging to the vitreous humour; but this has not been confirmed
by later observers. The late H. Miller distinctly says that there.
are not any other vessels on the outer surface of the corpus vitreum
than the retinal ones; and he also mentions that the retina con-
tinues long without blood-vessels—a fact which I have myself
verified in the human foetus, the moment of their appearance being
apparently determined by that of the obliteration of the arteria
hyaloidea capsule lentis. In the human foetus of the fifth month,
in which all the retinal layers except the bacillary were distinctly
recognizable, I found the retina still quite devoid of blood-vessels ;
the axial vessels going to the lens-capsule were still pervious; and
I failed to detect the vascular net on the hyaloid capsule described
by Von Ammon. ,

Absolutely fresh human embryos are so rarely obtainable that
the structure of the human vitreous humour in the earliest stages
of development is unknown. Before and after the fifth month
if consists of a web of delicate fibres, the meshes of which contain
a viscid colourless substance. Throughout this tissue, in chromic
acid preparations, numerous minute bright globules occur, which,

234 Histology of the Eye. [ Sone Woe a ee

mingled with the fibres, give, under a moderate enlargement (a
quarter of an inch) some resemblance to a stellar tissue. This
resemblance is, however, only superficial, and disappears under a
higher magnifying power which makes it evident that the bright
globules have not any definite relations to the fibres, since some of
them lie free in the meshes of the web, and others cohere singly or
in groups to the sides of the fibres or
at their intersections. Examined with
one-twelfth or one-twenty-fifth objec-
tive, these bright globules do not exhibit
any trace of structure; and I am dis-
posed to conjecture that they are arti-
ficial products, resulting from the action
of the chromic acid on the interstitial
albuminous substance. (Fig. 4.)

But, besides the formed elements
just described, there occur in the foetal
3 corpus vitreum other elementary parts

RStRL WAlRenaticaseae of the highest physiological importance

—large nucleated cells, which are most

abundant upon and near the hyaloid capsule and around the central

canal, but which are also found throughout the whole organ. Most

of them have a simple round or roundly oval shape; some -are

fusiform and branched. All are distinctly nucleated. Their
diameter ranges between z;/5oth and ,toth of an inch. |

In the human adult’s vitreous body, the foetal fibrillary net steps
into the background ; but it does not wholly disappear, for portions
of it persist even to old age; and it is replaced by delicate mem-
branes of such extreme tenuity, and differing so little in their re-
fraction from that of the fluid substance of the organ, that they
would elude detection, but for the presence of folds and the adhesion
of minute impurities to them. The arrangement of these mem-
branes is not yet certainly known ; and, in truth, their very existence
is doubted by some anatomists.

Beyond all doubt, the most important constituents in the
adult’s corpus vitreum are the large nucleated cells which I men-
tioned as occurring in the foetus. These embryonal cells persist
throughout life, and they are the starting-pomt of many of the
morbid changes to which this organ is subject.

They are endowed with an extraordinary formative energy,
normally latent, but promptly responsive to an appropriate stimulus,
the nature of which determines the dynamical direction this energy
takes. Anatomically, this excessive formative energy principally
manifests itself in two ways—one marked by a remarkable exten-
sion and fission of the cell-wall and contained protoplasm; the
other characterized by inordinate proliferation of the nucleus. ‘The

“Jour, Novia. | Histology of the Hye. wa

first produces, in its most complete form, very finely fibrillated
tissue. (Vig. 5.)

Where the fission of the cell-wall is carried to a less degree, it
produces open fibre cell-nets of coarser texture, which are often
combined with corrugated hyaloid membranes.

Proliferation of the nucleus in a minor degree 1s common in
association with chronic irritative affections of the vascular coats—
e.g. chronic glaucoma and the late stages of posterior staphyloma,
in which we find the cells larger than normal, but still retaining

Fibrillation of Cells of Vitreous Humour. Proliferation of Cells of Vitreous Humour.

their simple forms, and containing two, three, or several nascent
cells, instead of a single nucleus. But it is in suppuration that pro-
liferation is carried to its highest development. Advanced cases,
where the entire corpus vitreum is changed into a tough yellowish
substance, are not suitable for the demonstration of this; but,
before its metamorphosis is complete, at an earlier stage, in which
the opacity due to the presence of pus diminishes from the exterior
towards the still transparent centre of the organ, all the interme-
diate phases between the simple mononucleated embryonal cell and
perfect pus are easily traceable. (Fig. 6.)

The Tunica Uvea, so named from its resemblance to a grape or
large berry, wva, consists of two segments—the iris and the choroid
—which differ in their principal anatomical constituents and in
the offices which they subserve in the physiology of vision, and
agree mainly in both of them containing numerous blood-vessels
and much pigment.

The Choroid corresponds to the coat of lamp-black with which
we line the interior of the camera obscura, and serves the same
purpose, absorbing the incident rays, and so lessening dispersion in
proportion to the intensity of its pigmentation. But, the eye being
a living camera, the choroid has additional functions of another kind.
It directly ministers to the nutrition of the bacillary stratum of the
retina in man, as also to that of all the retinal strata in those
animals whose retinze are devoid of blood-vessels.

236 Histology of the Eye. [Sonmal, Neves

The vis corresponds to the diaphragm in the cornea. Stretched
across the anterior chamber, it stops out the most peripheral rays,
which, in its absence, would pass through the edge of the lens, and
in this way it lessens spherical aberration; then, by varying the
size of the pupil, it regulates the quantity of light admitted to the
retina; and, finally, it is an accessory of the apparatus of accommo-
dation, although not in man an actual factor.

The iris is essentially a muscular organ. The contraction and
dilatation of the pupil are due to muscular irritability, and not to
vascular erectility. Their continuance after the heart has ceased
to beat, and even after the head has been severed from the body,
are facts which place this beyond discussion.

In mammalia, the muscular tissue is of the unstriped kind;
while in birds and reptiles it is striped. One of the most useful
chemical agents for demonstrating it is the chloride of palladium.
The iris should be placed in a solution of this, containing from
one-fourth to one-eighth per cent., until it acquires a deep straw
tint. ‘The palladium chloride hardens the tissue, without making
it so granular and opaque as chromic acid does; and it beautifully
preserves the nuclei. With this reagent, its demonstration is easy
and certain in the eyes of white rabbits, where it is unobscured by
pigment which conceals it in human eyes.

The cells, which are not easily individually isolated, are long
spindles containing a rod-like nucleus. They resemble closely the cells
of the larger organic muscles. The cells cohere in small flat bands,
and these again combine in larger bundles. In man, I believe also in

Fie. 7.

ww

_—

=

— =

—_ >=
SS
SS
=—

—=
SSS
SS.

—

SSS

a
LS

Tris of White Rabbit, prepared with Chloride of Palladium, to show the disposition
of the Muscular Tissue.

mammalia generally, in birds, and in reptiles, the muscular bundles
are disposed in two sets, which have a radial and a circular direction,
and constitute a sphincter and a dilator muscle of the pupil. (Fig. 7.)

Moun, MOVERS] «Histology of the Hye. ae

In the white rabbit, the muscular bundles of the sphincter
pupille are disposed with great regularity in lines concentric with
the pupil, at the edge of which they form a very distinct band upon
the anterior surface. On the back of the iris, the outer border of
the muscular ring is less distinct ; and here, intersecting. the radial
bundles of the dilator, a thin layer of circular fibres is traceable for
some distance towards the great circumference of the iris.

The dilator pupille consists, in this animal, of slender bundles
running along the posterior surface of the iris from near the great
circumference towards the pupil, separating and combining again in
a plexus with long narrow meshes. On nearing the sphincter pu-
pillz, they spread slightly, and, intersecting with one another and
with the bundles of the sphincter, are lost.

The peripheral relations of the radial muscular bundles are less
easily made out. The difficulty is occasioned by the greater thick-
ness of the iris, and by the parallel direction of the very muscular
arteries. I am inclined to think that the bundles attach themselves
to the elastic fibres, which the ligamentum pectinatum iridis pro-
longs inwards to the iris. This very remarkable net of elastic
tissue, which fixes the great circumference of the iris to the margin
of the anterior chamber, is derived from the posterior elastic lamina
of the cornea, which in my last lecture I mentioned as having peri-
pheral relations with the ciliary muscle, iris, and sclerotic. These
I shall now explain. The lamina at the circumference of the cornea
resolves itself into fibrous tissue. This dehiscence begins first on
its anterior surface, and goes on until the whole membrane is con-
verted into fibres, which take three principal directions. One set
passes backwards and outwards to the sclerotic, behind the circulus
venosus in Schlemm’s canal; another set goes directly backwards to
the ciliary muscle; and a third set springs across the margin of the
anterior chamber to the great circumference of the iris, on the ante-
rior surface of which they form a network remarkable for its hard
stiff outlines, from which fibres are produced upon the front and in
the substance of the iris for a considerable distance towards the

upil.

The blood-vessels of the iris are very numerous. Its arteries
come from the arterial circle formed by the inosculation of the two
long posterior ciliary arteries, and known as the circulus arteriosus
ridis. ‘The mode of formation of this arterial circle is very vari-
able; but the ordinary plan is, that each of the two long posterior
ciliary arteries divides upon the outer surface of the ciliary muscle,
near its front, into a couple of primary branches, which separate
and encircle the iris, and meet the corresponding branches of the
other long ciliary artery. The arterial circle thus made sends
branches backwards to the ciliary muscle; others inwards to the
ciliary processes ; and a third set run forwards to the iris through

238 Histology of the Eye. [“Sournal, Nov. 1 1560.

the ligamentum pectinatum. These latter have, as Leber notices,
very thick muscular walls. They run from the great circumference
of the iris towards the pupil with a straight or wavy course, detach-
ing branches to the capillary net, which is very abundant, especially
at the anterior surface of the iris. On reaching the lesser circle of
the iris (the little circlet of minute irregularities on the front of the
iris near the pupil, which marks the attachment of the foetal pupil-
lary membrane), the now greatly diminished arteries join here in a
second arterial ring, the circulus arteriosus minor iridis. From
the inner border of this, capillaries extend mward, encroaching
slightly upon the sphincter, but not quite reaching the edge of the

upil.
‘ The veins of the iris lie nearer its posterior than its anterior
surface. They pass backwards, and, joming the veinlets of the
ciliary processes, convey the venous blood from the iris to the vasa
vorticosa. | :

The iris receives its nerves from the ciliary plexus—that exqui-
site net on the outer surface of the ciliary muscle. I can strongly
recommend osmic acid for their microscopical demonstration. If
the iris be placed in a solution of this acid holding about one-fourth
to one-half a grain per cent. for about twenty-four hours, we get the
nerves blackened, and the muscular tissue only slightly stained.
Stronger solutions are not so useful as the weak ones, because they
blacken more, and less discriminatingly; and, if the preparations
are left a little too long in them, everything is black alike, and
indistinguishable. (Fig. 8.)

The nerves of the iris, most easily studied in white rabbits and
guinea-pigs, are numerous. The larger bundles, containing several
fibres, converge from the great circumference of the iris towards
the lesser circle, forming, in their hitherward course, an open
plexus, the larger meshes of which are occupied by a finer net. At
the lesser circle, the nerves combine in a circular plexus, from which
single fibres are traceable inwards in the sphincter nearly to the
edge of the pupil. ‘The coarser bundles have a very abundantly
nucleated neurilemma. ‘The nerve-tubules vary greatly in size,
ranging between 33/75" and zy'00- All such tubules have a medulla ;
they are dark-edged fibres; while the smallest pale fibres which I
have traced were not more than yz4op" in diameter.

The interstices between the muscular bundles and the meshes of
the vascular and nervous nets are filled with a homogeneous con-
nective substance, in which simple, jagged, and very large, irregular,
and much branched connective-tissue corpuscles, plentifully occur.
Many of these contain a granular pigment, which, by its quantity
and distribution, produces the different colours of the iris.

The back of the iris is overlaid with a coat of pavement-epithe-
lium, loaded with granular pigment, which is sometimes called the

th { ical C
EIS ang Histology of the Eye. 239

uvea or uveal surface. The cells are less regular in size and shape
than those of the corresponding epithelium of the choroid.

Fig. 8. Nervous Circle.

Ciliary
Processes.

Pupil.

1}

Nerves of Iris, prepared with Osmic Acid. °

The front of the iris also has an epithelium. It is much more
delicate than that on the back, and more difficult to demonstrate.
Weak solutions of nitrate of silver are useful for this purpose.

In the Choroid we recognize two subdivisions—a larger poste-
rior portion, reaching from the optic nerve forwards as far as the
jagged line which marks the termination of the nervous retina, ora
serrata; and a smaller anterior portion, lying between this and the
iris, Which we call the ciliary body. So much of this latter as
belongs properly to the apparatus of accommodation, it 1s not my
purpose to describe in this lecture. My present remarks will relate
more particularly to the posterior segment. Its principal character-
istics are, its pigmentation and its great vascularity. This latter
much exceeds that of the iris; and, further, there is a peculiarity
in the arrangement of the blood-vessels—the capillaries lie apart
from the large vessels.

Enumerating the different tissues in the order in which they
occur in passing from the inner to the outer surface of this coat, we
first meet with a pavement-epithelium, borne upon a structureless

se Histology of the Eye. [Menus Meee

membrane, the elastic lamina of the choroid (Fig. 9); then the
capillary net, called the chorio-capillaris, and by the older anato-

Fig. 9.

Vertical Section of Choroid.

mists the tunica Ruyschiana ; next, the choroidal stroma, in which
the large vessels are imbedded; and, finally, a looser connective
tissue, which unites the choroid and sclerotic, named sometimes the
lamina fusca.

Fic. 10.

KZ

Y

Choroidal Epithelium. Choroidal Stroma.

The choroidal epithelium is formed of a single layer of flat poly-
gonal, mostly hexagonal cells, containing a nucleus and some brown
granular pigment. (Fig. 10.) In Albinos, in the white choroid of

Ee Histology of the Hye. 241
cetaceans, and upon the glistening silvery portion of the choroid,
called the tapetum lucidum in ruminants, solipedes, and carnivores,
the epithelium is also present, but it is devoid of pigment. In birds,
reptiles, fish, and amphibia, brushes of pigmented tissue pass in-
wards from the epithelial cells between the retinal bacilli. In man,
the diameter of the cells ranges between yqooth and sy5cth of an
inch; their average is about 775th.

The epithelium rests on a very distinct structureless mem-
brane—the elastic lamina. ‘This 1s often the seat of circumscribed
thickenings, which begin as little elevations of the inner surface,
and grow into knobs, and globes, and glandiform masses, large
enough to be seen, in a strong light, with the unaided eye. The
affection is one of those degenerations common in old age, but
which also occurs in young persons as a sequel of long-continued
local inflammation.

The choroid is supplied with arterial blood by the short posterior
and the anterior ciliary arteries. ‘The former, about twenty in
number, pierce the posterior segment of the sclerotic, some near the
posterior pole, others farther forwards. The hindermost are distri-
buted to the sclera and choroid around the optic nerve: and, here
inosculating with the capillaries of the nerve, they establish a col-
lateral channel, through which a little blood can enter the retina,
when the trunk of the arteria centralis is plugged by an embolus.
The remaining short posterior ciliary arteries run forwards with a
straight course, sending off short branches through the stroma to
the capillary net, where they break up quickly in an arborescent
manner. ‘The foremost of these arteries inosculate in front of the
equator with the anterior ciliary arteries (branches of the muscular),
which supply this region of the choroid. The capillaries form a
net immediately at the outer surface of the elastic lamina, the
meshes of which are smaller and less regular in the posterior
segment of the choriod than in the anterior, where they are wider
and longer. ‘The vessels are large ; and in all situations the inter-
stices of the net are relatively narrow, less broad than the diameter
of one of the overlying epithelial cells. We can recognize the col-
lective effect of the capillary net, but not the individual vessels com-
posing it in the living eye. (Fig. 11; p. 242.)

The blood of all the choroidal capillaries is collected by the well-
known venus whorls, vasa vorticosa, which empty their contents by
four short wide trunks which pierce the sclerotic very obliquely a
little behind the equator. The valvular form of these sclerotic
canals has been noticed by Leber, who adds the remark that it
would tend to hinder the exit of the venous blood whenever there
is an increased pressure on the inner surface of the eye-ball.

The stroma in which all the larger arteries and veins are bedded
is a modified connective substance. It contains, like that of the

VOL. IL. S

ae Histology of the Bye. [cus Ness

iris, branched pigmented corpuscles, which hang together in nets

and membranes, and send off long and very fine elastic fibres.

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Fig. 11.

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Chorio-capillaries.

The

thin layer of looser tissue external to the large vessels— the lamina

fusca—has an essentially similar structure.

Besides the branched and irregular pigment-cells, the stroma
always contains many pale, inconspicuous, roundly oval, and round
cells and nuclei, of about the size of lymph-corpuscles, which in-
crease considerably in number in inflammation, and which are, I
think, the tissue out of which the formed elementary products of

inflammation are evolved.

The nerves which we meet with in the choroid come from the
ciliary ganglion; they lie quite on the outer surface, often in
grooves in the inner surface of the sclerotic; and they all pass
forwards to the plexus on the outer surface of the ciliary muscle.
Whether any are distributed to the choroidal tissues has not yet
been made out with certainty; but there is this in favour of it,
that in the posterior segment very fine bundles of fibres, as well as

single tubules, occur.

In both the choroid and in the ciliary plexus, pale as well as

‘ug, MOM] Histology of the Hye. oe

dark edged nerve-fibres occur. In both situations, ganglion-cells are
present. These latter were, I think, discovered first by H. Miller
and by Schweigger. ‘heir demonstration is not always easy, or
even a certain matter.

In front of the ora serrata, the inner surface of the choroid ex-
hibits a circle of vascular plaits. First rising gently above the
surface, and then projecting freely, these compose the pars striata of
Zinn and the familiar ciliary processes. They are covered with a
pigmented pavement-epithelium, the cells of which are less uniform
than those of the posterior segment of the choroid. ach ciliary
process is a vascular plait, composed of large capillaries, which
receive their arterial blood by two or three branches, which come
off directly by a short trunk from the circulus arteriosus major
iridis, or which arise nearly as often together with one of the arteries
proceeding to the iris. ‘The litéle arteries enter the outer surface
(or rather edge) of the processes ; and small veinlets run along the
mner or free border; and they form a long meshed venous capillary
plexus, which conveys the venous blood backwards to the vasa
vorticosa. This venous capillary plexus not only transmits all the
blood from the ciliary processes, but it also receives veins from the
iris, as also some from the ciliary muscle.

In all vertebrates (except the lowest fishes, e. g. myxine and
Jancelet) a section vertical to the surfaces of the retina shows the
following superposed layers.

First, there is a layer of columnar bodies, the rods and cones
abutting against the choroid—the bacillary layer, known also as
Jacob's membrane. ‘To this succeeds the layer of corpuscles called
the outer granules. Next follows a fibrillated stratum—the inter-
granule layer; then another layer of corpuscles, the inner granules ;
next to this the layer, called by some the granular layer, by others
the grey vesicular or grey nervous layer ; then a stratum of ganglion-
cells ; and, finally, a stratum of optic nerve-fibres, bounded internally
by a thin membrans, the “ membrana limitans interna retine.”

In all these layers, nervous and connective tissues are intimately
commingled ; and it is just this interpenetration of the two tissues
which constitutes our principal difficulty whenever we attempt to
decide the nature of a particular retinal element.

Before proceeding to a detailed account of its tissues, a few
words on the best methods of studying the retina may be useful to
some readers. First, it is absolutely essential that the eyes be
perfectly fresh—the lapse of half-an-hour after the circulation has
ceased, or even of a few minutes if the eye have been opened, makes
differences in the appearance of the bacillary elements. Next, the
outer surface of the fresh retina should be carefully scrutinized, in
order to learn if both rods and cones are present. The latter will
be known by their greater stoutness, and by their outer ends lying

8 2

5, A Monthly Micros ical
244 Histology of the Bye. foutuly, ae

in a deeper level than those of the rods; while in birds, im some
reptiles, and in the batrachians, they are immediately betrayed by
their bright-coloured beads.

But there are many things which cannot be made out in the
fresh retina, or which can only be recognized by a practised observer
already familiar with their characters when they have been arti-
ficially hardened and stained. The fresh retina is also too soft to
allow us to cut vertical sections sufficiently thin without greatly dis-
turbing the tissues. The most useful agents are chromic and osmic
acids. Of the former acid, solutions of about a half per cent. are
most useful; they have a pale straw tint ; small eyes may be placed
in them entire, but large ones should be cut in two before immer-
sion. After remaining during three or four days in this solution,
the retina will be hard enough to allow sections to be cut sufficiently
thin for study with ,',-inch object-glass. The usefulness of chromic
acid lies chiefly in its hardening the retina, well, with little alteration
in the shapes of most of its elementary tissues, and enabling us
to cut our sections in any given direction we choose—for instance,
through the fovea, or tangental to it. But it has the disadvantage
of distorting the elements by distending them, when the solution is
too weak, or by shrinking them when it is too concentrated. It
also renders them granular and proportionately opaque. Sections
so prepared may be still stained with carmine.

Osmic acid is, in some respects, more useful than chromic. It
was first brought into notice by Max Schultze of Bonn, whose
labours have thrown much light on retinal histology. Solutions of
from a quarter to a half per cent. are best. It not only blackens
the transparent nervous tissues, making them distinct, but it enables
us, with a couple of fine needles, to split the retina in vertical
planes, which afford us beautiful sections much thinner and clearer
than any that the most practised hand can cut with the sharpest
knife. Another advantage is, that it does not make the tissues so
eranular as chromic acid ; but it has this drawback, that with it we
cannot run the section in any direction we choose. It is of greater
service in those vetebrates whose retinze are devoid of blood-vessels,
because their presence seriously interferes with clean cleavage. The
retina, stained and hardened by osmic acid may be kept for use in
distilled water without undergoing any further change during
several weeks. It is best mounted in glycerine for microscopic

‘examination.

To return from this digression to the description of the retinal
layers ; in the outermost or bacillary there are two sorts of elements,
distinguished as rods and cones.

Every rod and every cone consists of two segments—an outer
one, the bacillus or shaft ; and an inner one, the appendage or body.
The shafts of both rods and cones are highly refracting conspicuous

Monthly Microscopical :
Journal, Nov. 1, 1869. Histology of the Kye. 245

microscopic objects; whilst the appendages are pale, have a low
refractive index, and are less evident.

The inner and the outer segment are separated by a sharp trans-
verse line, where the slightest violence snaps them asunder.

The rod-shaft is a long, slender cylinder—in profile, a narrow
rectangle. The ends are truncated ; the outer rests on the choroidal
epithelium, and the inner joins the appendage. In the perfectly
fresh shaft I cannot discern any differentiation of parts, except an
external outline, indicative of a containing membrane, and a homo-
geneous contained substance; but very soon after death the shafts
begin to alter. The fresh perceptible change is, I think, a very faint
longitudinal striation, and this is followed by the appearance of cross
lines, which divide the shaft mto light and dark segments; at the
same time the shafts swell and bend and lose their rectilinear figure.
This segmentation, which must have been familiar to every one
since Hannover first wrote on the retina, I have never seen in abso-
lutely fresh shafts examined instantly after death; so that, in
common with others, regarding it as a post mortem change, I did
not attach much importance to it. Professor Schultze, however,
has founded upon it the ingenious view that the shafts are built up
of dises of alternately nervous and connective substances.

The inner segment or rod-appendage has commonly the shape
of a slender triangle or spindle; and one of the outer granules, as I
shall shortly show, is always associated with its mner end. In its
outer end, immediately inside the line which marks it off from the
shaft, there may often be seen, particularly in the large rods of
amphibia, a small hemispherical body of the same refractive index
as the shaft to which it sometimes remains attached when the shaft
and appendage separate. It was long ago described by the late
H. Miller, whose loss every histologist deplores, and I figured it
myself in a communication to the Royal Society in 1862. Schultze,
who has lately called attention to it, suggests that it may act as a
collecting lens. | |

The outer segment of the cones—the cone-shaft—is usually
shorter than the rod-shaft, and it commonly tapers slightly outwards,
the outward end being slightly narrower than the inner. The cone
appendage is usually flask-shaped or bulbous; and, like the corre-.
sponding part of the rod, its inner end always has its associated
“outer granule.” In the outer end of the appendage in birds, in
some reptiles, and in batrachians, lies the well-known coloured bead
which forms so exquisitely beautiful a microscopic object in the
retina of these animals. 3

The interstices between the bacillary elements are occupied by
a soft, homogeneous connective substance, which in all vertebrates
below mammals contains a granular pigment. This extends inwards
from the choroidal epithelium around and between the shafts as

° ° Monthly Mic ica
246 Histology of the Eye. Journal, Nov. 1, 1869.

far as their line of union with the appendages. It completely
insulates the shafts, and would have the effect of absorbing any
pencil of light which, making a relatively small incident angle,
might escape laterally outwards through the shaft-wall, and in this
way the escaped pencil would be prevented from entering a neigh-
bouring shaft.

In mammals, the greater slenderness of the shafts probably
renders such a provision unnecessary, because the incident pencil,
to enter the shaft, must nearly coincide with its axis; and, as regards
the side of the shaft, the angle of incidence would be so large that
the pencil would probably be totally reflected.

The inner ends of the rods and cones pass through apertures in
the connective membrane, called the membrana limitans externa
retine, and are produced inwards amongst the outer granules as
slender bands or fibres. The membrana limitans externa is the
sharp, hard line, always perceptible in vertical sections between the
bacillary and the outer granule layers.

That the rods and cones are the percipient elements in the
retina is now universally received, so that it needs hardly be men-
tioned ; but it may be well to adduce the chief considerations on
which this presumption rests. First, they alone of all the retinal
tissues are so arranged as to be capable of receiving separate and
distinct stimuli from small incident pencils of light. Next, their
absence entails absence of perception. Mariotte’s experiment proves
this as regards the optic nerve disc, and the increase of the size of
the blind-spot in myopia from posterior staphyloma, proportionately
to the extent of the white atrophic crescent—a fact which 1s easily
roughly verified—is another proof of the same thing ; because here,
together with the disappearance of the choroidal epithelium and
chorio-capillaris, I have had opportunities of proving microscopi-
cally the absence of the cones and rods.

When we endeavour to press our inquiries farther, and try to
ascertain what may be.the respective functions of the outer and
the inner segment of the rods and cones, and in what respect the
functions of the rods and cones differ, we meet with difficulties
which have yet to be overcome.

As regards the first part of this mquiry, the high refractive
index of the shafts, and their insulation by a coat of pigment in
many animals, points to a physical optical réle; while the asso-
ciation of a nucleus (an outer granule) with the appendage, suggests
a more vital dynamical share. If this be so, then the junction
between the shaft and appendage marks the line where, so to say,
the physical vibrations of light are converted into nerve-force. |

Towards the solution of the second point of the inquiry, Schultze
contributes the important fact that nocturnal mammals, as the
mouse, bat, hedgehog, have no cones; and that in owls, they want

Boca, Non es Histology of the Hye. 247
the bright orange and ruby beads of diurnal birds; and from this
he conjectures that the cones may be concerned in perception of
colour. 3

The outer granules, to which I must now pass on, are not
minute, angular, solid particles, as their name implies, but cells or
nuclei of very appreciable dimensions. ‘Their numbers are directly
proportionate to those of the rods and cones: and it 1s very pro-
bable —I may say certain—that each outer granule is associated with
a rod or cone, and this in one of two ways. When the rod or
cone-appendage is large enough to hold it, the outer granule lies
inside the appendage in the plane of the membrana limitans interna,
or at its inner surface; but, when the appendage is too slender to
contain the granule, it is jomed to the granule by a communicating
fibre, the length of which is determined by the distance between
the inner end of the appendage and the granule. In either case,
the appendage is prolonged inwards in the form of a band or fibre
beyond the “outer granule” towards the next stratum. This
fibre I call the primitive bacillary fibre, or the primitive rod or
cone-fibre, when I wish to distinguish it more particularly.

The entergranule layer, which, as its name conveys, lies between
the outer and the inner granules, is a fibrous stratum. Some of
its component fibres are nervous, passing between the outer and
inner granules, and others are connective tissue. Of the latter set
of fibres, those which traverse the layer vertically belong to the
system of connective radial fibres, known by the name of their
discoverer, H. Miller. The others, which extend parallel to the
direction of the layer, constitute its proper substratum; and
amongst these le imbedded small nuclei, and in some of the lower
animals, e.g. chelonians and fishes, large branched corpuscles of
very considerable dimensions.

The enner granules, like the outer ones, are also cells or nuclei.
According to their sizes, which vary much, they fall into two sets
smaller granules, everywhere numerous; and larger ones, most
abundant near the inner surface of the layer, which I cannot dis-
tinguish from ganglion-cells. On the one side, the inner granules
receive the fibres sent inwards towards them through the inter-
eranular layer from the outer granules; and, on the other side,
they send fibres inwards into the granular layer towards the
ganglion-cells. .

The granular layer, as Schultze correctly pointed out, is re-
solved, by a sufficiently high magnifying power, into a very finely
fibrillated spongy web, which manifestly hangs together with, and
is In great part a derivative of, the connective radial fibres entering
it. The only nervous elements occurring in it are the internuncial
fibres which traverse it, and the outermost ganglion-cells bedded in
its inner surface. The term granular, which simply expresses its

y Monthly Mi
a Histology of the Hye. [Neus Nemes

appearance under a low power, is therefore preferable to that of
grey vesicular or grey nervous layer, which gives a wrong idea of
essential composition.

The cells of the ganglionic layer possess a very distinct roundish
nucleus, imbedded in a pale and very soft protoplasm, about which
there is not generally any distinct cell-wall perceptible. I believe
that all the cells are branched. The outer branches, which are the
more numerous, run outwards into the granular layer to join those
coming inwards from the inner granules, while their inner branches
join the bundles of optic nerve-fibres.

These last radiate in a plexiform manner from the optic nerve
entrance. Where there is a fovea centralis, as in men, apes, some
birds, and reptiles, the nerve-bundles are so distributed that those
only destined for the fovea and its surrounding macule pass directly
to it; while those bundles going to more distant parts beyond the
fovea arch around it. With some exceptions, the nerve-fibres are
devoid of medulla. In our own eyes, this ceases at the lamina
cribrosa; and only pale fibres, equivalent to axis-cylinders, with
perhaps an investment of the sheathing membrane, are produced
into the retina.

The connective-tissue frame, which supports and holds together
the nervous elements, consists of three segments. First, there are
the two membranes ;—the outer limiting membrane, which I have
already described ; and the membrana limitans interna, which some
identify with the hyaloid capsule of the vitreous humour, but which
I regard as a distinct membrane. This distinctness cannot be
always demonstrated at pleasure; but I believe it to be a fact,
because I have found the two membranes separated by inflam-
matory effusions, and because in the eyes of a Burchell’s zebra, for
which I was indebted to the liberality of the Zoological Society, I
found a beautiful pavement of epithelium on the outer surface of
the capsula hyaloidea. ‘The second member of the connective sub-
stances 1s a system of stout pillar-like fibres, which arise by ex-
panded wing-like roots from! the outer surface of the limitans
interna, and traverse vertically all the layers in a direction radial
from the centre of the eye-ball. ‘These are the fibres which, when
originally discovered by H. Miller, were believed by him to link
the percipient elements on the outer side of the retina—the rods
and cones—with the conducting optic-nerve fibres at the inner
surface of the retina, an error which he himself was one of the first
to correct. They form a frame, which mechanically binds together
the several layers in their order. Lastly, the retina contains a
large amount of interstitial connective tissue, which is accumulated
in larger quantity between the inner and outer granules, and between
the inner granules and ganglionic layer, but which also pervades,
in smaller quantity, all the nervous layers except the bacillary.

hl i .
"Journal, Nov. 1, 1809. Histology of the Hye. 249

Spinning an excessively fine web around the cells and fibres, it
maintains them all in position, and it supports the blood-vessels
when these are present. ‘To sum up, the connective tissue occurs
in three forms—membranous, as the membrana limitans externa
and interna; fibrous, as Miiller’s radial fibres; and as an exces-
sively finely-fibrillated interstitial web.

It isa remarkable circumstance that the retina in the greatest
number of vertebrate animals does not contain any blood-vessels.
A retinal vascular system is confined, I believe, to mammalia ; and
amongst these there are great differences in the distribution of the
vessels. In man, the whole extent of the retina, from the optic
nerve entrance to the ora serrata, is vascularized ; and the same
obtains, I believe, in the ox, sheep, deer, and antelope; while in the
hare the vessels are restricted to the area of the opaque nerve-
fibres; and in the horse they form a narrow zone around the optic
nerve entrance.

In the human retina no capillaries penetrate farther outwards
than the intergranule layer or the inner surface of the outer granule
layer. In consequence of

Fig. 12.
mi
|
ie

this arrangement, the rods
VANISH:
en
sey

and cones are nearer to |
the chorio-capillaris than tof
the retinal capillaries. ‘This {
alone would make it pro- 7
bable that they derive their
nourishment from the capil-
laries ; and morbid anatomy
abundantly confirms this, for
it is an established fact that
atrophy of the chorio-capil-
laris, entailing atrophy of
the hexagonal pigment epi-
thelium, is also followed by
atrophy of the rods and
cones. :
In the common hedge-
hog I have observed a pecu-
har disposition of the ves-
sels, which is intermediate
between the typical distri- a
bution in = and most mudd JN
other mammals I have eX- Vertical Section of Retina, to illustrate the Distribution
amined, and that which ob- eae eae rs
tains in the lower vertebrates; viz. the larger vessels, arteries, and
tee the capsula hyaloidea, while capillaries only pierce
e retina.

250 Histology of the Hye. cena
In fish, batrachia, and reptiles, the vascular net which pervades
the capsula hyaloidea represents the retinal vascular system of
mammals, but in birds this hyaloid net is wanting; and the great
_ development of the pecten was thought by Miller to be a compen-
satory provision for both its absence and that of retinal vessels.

I will now pass on to notice—and I can only do so very
briefly—the characteristic modifications which the retinal elements
undergo in the five vertebrate orders. |

In fish, the retina is distinguished by the occurrence of cones
of a peculiar kind—double or twin cones, as they are commonly
called—by the large quantity of connective tissue it contains, and
by the presence of very large branched connective tissue corpuscles
in the intergranule layer.

Lhe twin-cones have distinct outer segments or shafts. Their
symmetrical appendages are joined together down one side, and at.
their inner end they sometimes appear, to be actually continuous..
Each twin has, I think, its own outer granule, and detaches a
separate fibre inwards.

The Batrachian retina is distinguished by the large size of its.
elementary tissues: the rods are very large. ‘The cones, which are:
smaller, contain a pale yellow or colourless bead. Twin-cones have
been discovered in it by Schultze. .

Amongst Reptiles, lizards possess cones only; these contain a
pale yellow bead (in all I have examined). ‘They are single and
twin; but the twin-cones differ in many respects from those of fish.
They are unsymmetrical in form, and one is beaded while the other
is beadless. Their union is much less intimate than that of the
fish’s twin-cones. A little violence frequently disassociates them.

The chameleon, iguana, gecko, and many other lizards, have a
fovea centralis, from which the primitive bacillary fibres radiate
towards the periphery of the retina, and pursue an oblique course
from the outer towards the inner surface of the retina, crossing the
vertical radial connective tissue fibres, which enables us easily to
distinguish the nervous and connective tissue fibres in this region.

In many lizards, a well-developed, conical, or sword-like pecten
stands forwards from the optic nerve in the vitreous humour
towards the lens. In the common alligator, and in the Nile croco-
dile, there is no projecting pecten, but the optic disc is marked
with a brown pigment. :

The blind worm’s retina closely resembles that of typical lizards,
especially in the presence of a pale cone-bead.

A cone-bead is wanting in snakes. In other respects, their
retina resembles that of lizards.

The common English snake has no pecten: the viper has a
rudiment of one ; and the boa’s optic nerve has a minute globular
one.

Monthly Mi ical x
Journal, Nov. 1, 1869. Histology of the Eye. 251

The Chelonian retina agrees very closely with that of birds.
Both are distinguished by bright cone-beads, and by twin-cones, the
structure of which, particularly in chelonia, resembles that of lizards,
and differs in the same way that this does from that of the fish’s
twin-cone. Hach twin has certainly its own outer granule, and its
separate primitive cone-fibre, which, as in lizards, takes an obliquely
radial direction from the posterior pole of the globe. The cone-
beads are of three colours—ruby, which are the largest; and
orange, passing through pale yellow into pale green: the orange
and green beads are the most numerous. The intergranule layer
contains large branched connective tissue corpuscles, resembling.
those occurring in the same layer in the fish’s retina.

The Bird's retina, as I have just said, agrees in several par-
ticulars with that of the chelonia. It has cones with beads of three
colours, except in the case of nocturnal birds, e.g. owls, in which,
as Schultze first showed, all the beads are pale, almost colourless,
a light yellow. It has also twin-cones, like those of reptiles. In
many birds there exists a very distinct fovea, and in some H. Miiller
- discovered two, one at the posterior pole and the other near the ora
retin, the former being affected by the incident pencils in mono-
cular vision, the latter coming into use in vision with both eyes.
The primitive bacillary fibres radiate obliquely from the fovea, as
in man and reptiles.

The Mammalian retina is marked by the absence of twin-cones
and of cone-beads. Its elements are smaller than those of the
lower vertebrates. That of man has a macula lutea, in which is a
distinct fovea centralis. The macula lutea occurs also in certain
apes. The bat, mouse, hedgehog, and certain other animals,
chiefly of nocturnal habits, have rods only; mn most others cones
and rods aré both present, as in man. The retina is vascular; the
distribution of the vessels, however, varies in different families.

There are two situations where the structure of the retina in
man and some other vertebrates which I have particularized is
peculiar; these are the macula lutea and the ova retine. The
macula lutea is an oval spot, at the posterior pole, of a yellow
colour: the coloration is not produced by granular pigment, as in
that of the choroid, but it is a diffuse stain of the elementary tissues.
In the centre of the macula is the minute pit—not a perforation—
the fovea centralis. This pit is produced by the radial divergence of
the primitive cone-fibres from a central point, and by the thinning
and outward curving of all the retinal layers (except the bacillary)
as they approach this point. In the fovea and the macula, except
at its periphery, cones only occur, and they are more slender and
longer than in other parts of the retina. The greater length is
chiefly due to the elongation of the cone appendage. The slender-
ness of the cones does not allow their appendages to include the

| Monthly Mi i
aoe Histology of the Eye. sound, Nor

outer granules, so that these latter lie, all of them, at the inner side
of the membrana limitans externa. Owing to the radial direction
of the primitive cone-fibres, the outer granules belonging to the
central cones lie peripherally, so that the outer granular layer is
absent from the foveal centre.

At the inner surface of this layer the cone-fibres combine in a
plexus the bundles of which, near the centre of the macula, are
directed obliquely towards the inner surface of the retina; between
the centre and the circumference of the macula they assume a
direction nearly parallel to the retinal layers, and at the circum-
ference of the macula they run nearly vertically,

At its inner surface, the cone-
fibre-plexus breaks up into primi-

HiGe 3.

—— tive fibres, which pass through
FIG — a, thin connective tissue stratum,
oi eu -\<fz2, the intergranule layer, and enter
é;, Al sx 2? the inner granule layer. This
ge \an <2\é4 latter, at its beginning in the
oF / ; centre of the fovea, is not sepa-
ARE cule Ae = NB |2yi\s rate from the ganglionic layer.
ASB \ Ve \S eye ‘The nerve-fibres pursue in it
etic) a: |e. \*\¢,, the same direction as in the outer
OPE ley es )=\*'~ granule layer.

Primitive Bacillary Fibres, from the innermost The ganglionic layer, at the
Bundles of the Cone-fibre-plexus, traversing the periphery of the fovea, contains

Intergranule Layer. :
three or four tiers of cells;
these become fewer towards the foveal centre, but even here they
lie in a double or treble series, bedded in a granular tissue.

The ora retine is the other situation to which I referred as
having a peculiar arrangement of its tissues. Being less important
than the fovea, I can notice it only very briefly. Towards the ora
the nervous elements gradually become fewer, the layers thin out,
the beads and cones shorten and become stouter. With this decrease
of the nervous tissues, the connective tissues predominate, and they
are prolonged beyond the ora as the pars ciliaris retin, the radial
fibres becoming, according to Kolliker’s observations, the columnar,
epithelial-like bodies which line the pars striata.

ONG eo. Spontaneous Generation. 253

Ill —EHzperiments on Spontaneous Generation. By Epwarp
Parritt, Curator of the Devon and Exeter Institution.

Lire is one of the great problems that has engaged the attention
of the most profound thinkers and writers of both ancient and
modern times. In our own time this problem seems to have excited
more to investigate its mysteries than that of any other period of
which we have any record, and more experimental philosophers
have entered the field now than at any other time; and even now
philosophy and chemistry have failed to explain what that wonder-
ful vis vite really is.

It is the opinion of one or two of our philosophic naturalists
that the distance between them and the vital spark is gradually
becoming less; that they are, in fact, enclosing it within a wall of
argument and experiment, and that at last it must yield to their
investigation.* “ But even if it could be shown that the chemical
actions that go on in the organism are no other then what can be
imitated in the laboratory, it would still be certain that life is not
a mere resultant from any physical and chemical forces, and that
there must be a distinct vital principle.”

It is the opinion of some that the act of crystallization and the
vis vite or vital force are one and the same thing. In this I cannot
agree. ‘There appears on the surface a great similarity, I admit,
and the laws which govern the formative process would appear to
be identical; but having arrived at the ultimate form in crystalliza-
tion, there the matter stops. On the other hand the case is very
different in its results; for an animal or plant, be it ever so low in
the scale, is each endowed with a property peculiar to an organized
body ; namely, that of reproduction.

This, then, at once separates the organic from the inorganic
kingdoms. The perpetuation of the vital principle as compared
with the highest forms of crystallization, and which, so far as we
know, we may term the ultimate, is to my mind separated at once
and for ever by the perpetuation of the vital principle.

Buffon imagined life-like matter to be indestructible, and that
each organism was built up of a number of molecules, and that each
molecule had a life of its own, and the death of one of these complex
compounds was simply the dissolution of one of these associations ;
and thus he says, these molecules are again set at liberty, and
wander about until they are once more combined with an animal
or a plant; and as Coleridge has beautifully said—

“ Organic harps are living things,
That tremble into thought,

As the one breath sweeps o’er their strings,
The mind that has them wrought.”

* Murphy: ‘ Habit and Intelligence,’ vol. i., p. 88.

254 Experiments on [Menthly, ateroseopea

Spinosa, who held a rather different opinion to that of Buffon,
believed that there is in nature only one substance, and that this
substance is infinitely diversified, having within its one essence the
necessary causes of the changes through which it goes.

In the investigations into the development of life, and to which
the title of Spontaneous Generation has been given, I desire to direct
special attention. We have in this something similar to that to ©
which Buffon alludes when speaking of “ the wandering molecules.”
For when the portions of the organisms have become disintegrated
or broken down, the molecules and cells of which they were formed
are set free, and it is to the study of these in their separate and
also in their aggregate forms that I desire to direct attention. A
molecule is believed to be an aggregation of atoms; and it is only
in the molecular form that we are able to recognize matter in its
highest state of disintegration ; and although we are enabled to
examine with our instruments the apparently extreme points of
matter, yet there is a world which lies beyond, as yet invisible—the
“atomic.” One of the most recent and apparently one of the best .
informed philosophers in treating of this subject—the “atomic
theory ”*—Professor Bayma—hbelieves each atom to be spherical
in form, and surrounded by a repulsive electric ether, the atom
itself being attractive; and that every point of matter acts instan-
taneously upon every other point at all distances, however great or
small, with a force having the same character at all distances, and
inversely to the square of that distance. But I hold with Professor
Norton that this is assuming too much, as no proof has been esta-
blished that an atom is spherical in form, or that it is a material point.
“In fact, it appears to be highly probable, as supposed by Brodie,
and strongly urged by Gerhardt and his followers, that few if any
elementary substances in their uncombined condition are really
known to us; the so-called elementary bodies being really com-
pounds of at least two atoms of the true element with each other.
Thus hydrogen gas is not simple hydrogen, but is H,, or 1, hydride
of hydrogen, and so on with others.” T

We set out, then, as Mr. Herbert Spencer t says, “ With mole-
cules one degree higher in complexity than those molecules of
nitrogenous colloidal substance into which organic matter is re-
solvable; and we regard these somewhat more complex molecules
as having the implied greater instability, greater sensitiveness to
surrounding influences, and consequent greater mobility of form.
Such being the primitive physiological units, organic evolution
must begin with the formation of a minute aggregate of them—an
ageregate showing vitality only by a higher degree of that readiness
to change its form of aggregation which colloidal matter in general

* ¢ Philosophical Magazine,’ 1869. t+ Miller’s ‘Chemistry,’ vol. iii.
t ‘Principles of Biology,’ vol. 2, p. ii, 12.

TheMonthlyMicroscopical Journal. Nov.11869.

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Products of spontaneous (@? Generation.

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aL Nee Ce, Spontaneous Generation. 255

displays. A further stage of evolution is reached when the very
imperfectly integrated molecules forming one of these minute
aggregates become more coherent, at the same time as they pass
into a state of heterogeniety, oradually i increasing in its definite-
ness.’

Dr. Winslow,* in speaking of the forces exerted upon mole-
cular matter, says, “In whichever light we study the action and
reaction of these binary elements of mechanical energy, Or vis, we
observe all the phenomenal results in crystals, plants, or animals
to develop themselves upon crucial and bilateral principles, and all
the secondary forces to follow the same axial and equatorial lines of
propagated molecular force and motion.”

This is exemplified in a remarkable manner in the molecular
movements in all the experiments that I have instituted. We first
observe a homogeneous molecular mass (Plate XXXIT., Fig. 1) float-
ing or suspended in water, which has been added ; and almost as soon
as the infusions have become cold we observe a remarkable movement
has taken place with the molecules; part of this is, I presume, from
the loss of heat. They have already begun to form themselves into
some definite shape (Fig. 2). There have, then, been forces at work
imperceptible to us, except that we see the results of those powers
in the formative process that is going on. The same, or apparently
the same, formative process may be seen, I admit, in the act of
crystallization, as the suspended molecules are drawn towards each
other by a force that is termed affinity or attraction; but when the
erystal is formed, the process is complete. This same process may
be repeated by the addition of other and similar crystals, but this
is all; here crystallization ceases ; it can go no farther. The same
laws that govern both organic and inorganic matter, when each are
placed in similar conditions, appear to act the same on both; the
same influences are exerted on both, and apparently in the same
degree ; indeed, the two seem to run in parallel lines to a certain
distance ; at last the inorganic stops; it has reached its ultimate
form. Its hitherto companion is still acted on by the same forces:
it is carried forward, and here the true wis vite, or life-force, is
really seen. We now see distinctly the difference between the
organic and the inorganic kingdoms. When the two started, we
saw what we believed to be the same energy acting equally alike
on both—the vis or force, the vitz or principle of life, had not then
manifested itself.

But the very fact of life being transmitted or carried forward
implies a force or energy. At the same time ‘it is not a mere
mechanical force, such as we saw at work in the formative process
of crystallization, but a life-force, a force that implies that some
other and peculiar property is bound up with these mechanical forces.

* “Force and Nature,’ p. 282,

256 Experiments on ["Sourna, Nov. 1, 1865.

“Force so combined with force as to produce certain definite and
orderly results: this is the ultimate fact of all discovery.” *

Mr. Browning, in ‘Transactions of the Royal Microscopical
Society’ for July 1, p. 18, says:—“'There are probably some
grounds for believing that the particles or molecules in magnets
are always in motion ;” and, he says, “ Mr. Wenham once told
him that he had seen a cavity in a crystal partially filled with
a fluid, and for several years this fluid had been unceasingly in
motion, although completely shut off from the surrounding atmo-
sphere. Motion, then,” he says, “is not peculiar to life; and we
shall be brought at last to the single distinction—reproduction.”
In this I fully concur, as I had arrived at the same conclusion, as
before stated. Mr. Browning goes on to say, curiously enough, in
the very next sentence, that what he had just approved is not true,
and cannot be accepted; for, he says, “The difficulty here would
be insuperable, if we were compelled to accept the hypothesis that
life is transmitted from one organism to another. But this
hypothesis is no longer generally accepted. Professor Owen, who
has been until recently opposed to such views, has at length
accepted the hypothesis of spontaneous generation.” This passage,
I think, would puzzle a Philadelphia lawyer.

The term “spontaneous generation,” although it expresses a
certain meaning, I think is not admissible; although we see things
apparently springing into life where no ‘life appeared to exist,
yet in a few hours every molecule is a moving, living body. Tn
this light it seems to me more like suspended animation ; and that
every molecule, directly it is set free, is seen dancing about in the
infusion, like gnats in the sunbeams, and apparently as full of
the enjoyment of life. And it would also seem as if an organism
was composed of an infinite number of these, and that, when set
free, they returned to their original conditions ; for the oreat variety
of both ‘animal (or what we believe to be animal) and vegetable
forms, which are developed in a single infusion of either animal or
other organic matter, would almost warrant us in believing such to
be the case ; but at present it would not be prudent to venture so far.

Again, when we examine our infusions, whether they be made
with vegetable or animal, we detect life, or what we believe to be
life (and not mechanical force), in the most minute points or mole-
cules that our instruments enable us to observe; and why I believe
this motion to be life is, that we see the molecules in different
stages of development. At the same time I am fully aware that
motion does not distinguish an animal from a vegetable, as many
plants are endowed with that property.

The most minute and searching microscopic investigations have
availed us but little in the elucidation of the mysteries of life. One

* Duke of Argyll: ‘ Reign of Law,’ p. 81.

ee Las Spontaneous Generation. 257
great thing it has done for us, and that is this, it has opened up a
vast field of research, and carried our knowledge into infinitesimal
matter, in which it thins away until it seems to vanish into thin
air, and yet as far as the eye can see does life reside. The minute
cells of which both plants and animals are built up, the very petals
of the flowers, and the eyes of the human subject, are swarming
with life, not their own, but myriads of independent creatures, so
that at last we are almost forced to accept the words of Buffon, as
referred to in the first part of this paper.

Thales supposed all things to be generated out of water; and in
this he was not far wrong, as the beginning of life, so far as we are
enabled to appreciate it, is mainly dependent on a certain state of
humidity for its existence. Amongst the protophytes, or simplest
plants, there are many of which every single cell is not only capable
of living, but may be normally considered a distinct plant. For
instance, observe the beginning of a lichen on a newly-hewn stone.
It will there be seen to spring from a single cell, and this cell,
should the condition of humidity continue favourable, will very
soon develop others, so that in a short time a thin stratum of cells
may be observed radiating in all directions.

In the infusion of the liver of a fowl, and to which I shall again
have to refer, I observed on my first investigation, eighteen hours
after the infusion was made, a number of bluish elliptical cells, very
much like the spores or cells of a penzezlliwm ; these had the power
of propagating or continuing their like by a kind of gemmation,
that is, the inner walls of the cells appear to develop minute gemma,
or little buds, which spring into cell-life; and it frequently happens
that one single cell may contain many generations of cells, as they
are graduated down to extremely minute points, and at length lost
to view. These cells propagate very rapidly, forming themselves
into long moniliform masses. Now the difficulty is how to account
for these cells in this infusion, as I had done all that I could do
to destroy life, by boiling the liver until it was all, or very nearly
all, broken down or disintegrated, so that it appeared only as a
molecular or flocculent mass. These cells measured about +s3ooth
of an inch long. My impression is, that these cells were embedded
in the flesh of the liver, as I do not believe them to have been
admitted through the agency of the atmosphere into the vessel.
Every provision was made to make the experiment as perfect as

ossible.
P Dr. John Lowe* mentions the case of peculiar cells being found
in the lungs and kidneys of a man. These cells measured +53y oth of
an inch, which correspond very nearly with the size of those found
by me in the liver of the fowl. Ido not agree with M. Pasteur in
ascribing to the agency of the atmosphere the various vegetable

. * ‘Hdinburgh New Philosophical Journal,’ 1860.

VOL. II. T

258 Haperiments on Wesepen ae
cells that have been found in the numerous infusions that have been
made in the investigations of this so-called “Spontaneous Genera-
tion ;” for although I have studied fungi for at least twenty years,
I have never found them so abundant as to fill the atmosphere so
completely with sporules as some would have us believe, and that
at all seasons of the year, and in every condition,}in the still atmo-
sphere of a room equally with that in the open air.

The extreme difficulty of destroying lite I have found in every
experiment, for neither baking nor boiling will destroy it; these
may change the form and outward condition of the things operated
on, but you cannot drive life entirely out of it by either of these
processes.

The greatest heat that has been applied to experiments of this
kind is 200° centigrade, or 500° Fahrenheit, and even then, says
M. Pouchet, animalcules and fungi are developed. ‘“ Neither calcined
air, sulphuric acid, liquor potassze, gun-cotton, nor a boiling tempe-
rature have prevented the production of infusoria, or destroy the
supposed germs in the air or infusion.”*

If we take the case of sarcina ventriculi, as found not unfre-
quently in the human stomach, and also the vegetable sporules
found in the kidneys; the temperature of the stomach averages
about 98°. Again, take plants, such as wlva thermalis and others,
which live in the hot springs. But it may be said that these
plants are adapted to places in which they are found, and it is
consequently natural to them. Be it so. But still it shows
us that a heated medium is not antagonistic to vegetable life.
M. Pasteur says, that the boiling temperature, that is, 100° centi-
erade, does not prevent the growth of the germs in the atmosphere ;
but, he says, that 130° centigrade always destroys their vitality.
This, it will be observed, is directly opposed to the experiments
instituted by M. Pouchet, as before stated, that the temperature of
the infusions may be raised to 200° centigrade, and yet animalcules
and fungi are developed.

There is one very remarkable thing to be observed in all the
experiments that I have prosecuted, and that is this, that all
the larger and stronger plants, if I may call them so, have
sprung from the oil-globules. This ’may be said to be in favour of
M. Pasteur’s argument, that the germs are admitted with the atmo- _
sphere ; and as the oil, being lighter, generally floats on the surface
of the infusion, the germs are first brought mto contact with it;
and finding a proper and rich medium in which to vegetate, they
rapidly spring into life, the result of which we see in our micro-
scopic examinations of the infusions. ‘This, although it appears so
favourable to M. Pasteur’s hypothesis, is not true in the main; for
I have carefully examined other parts of the infusions, and particu-

* Dr. Hughes Bennett, in ‘ Popular Science Review,’ January, 1869.

Mourns), Nov. 1, 1609, Spontaneous Generation. 259

larly the flocculent matter, which also contains oil-globules, and which
is generally held in suspension, and floats near the bottom of the
infusions, to be equally abundant in vegetable organisms as those
masses which float on the surface; and in the case of the liver of
the fowl, a small portion which remained entirely at the bottom of
the vessel developed one of the largest growths that I have yet
seen, and which I believe belongs to the genus Leptomitus, and is
very nearly allied to L. lacteus, but it differs from that species in
not being constricted at the joints. Again, on this same piece of
liver arose a rather large inflated film, or what appeared to me a
protoplasmic or structureless thin jelly; this never was brought
into contact with the air at all, except when I took up a portion of
it with a glass tube, to place it under the microscope; and yet this
film had embedded in it quite a network of illiptical sporules, not
molecular bodies, but having all the appearance of sporules of some
mucorinous plant. This, then, to me, who saw this remarkable
structure, would prove a great stumbling-block to the acceptance of
M. Pasteur’s theory. This structure appeared on the eighth day
after the infusion was made (Fig. 8).

I began my experiments in this way: I prepared three glass
vessels by thoroughly cleansing them and boiling them; I then
dried them at the fire. I then took part of the liver of a fowl
directly from the bird, and placed it in one of the vessels, covering
it instantly it was taken out; I then poured about two inches of
boiling water into it, keeping it covered, except when the water
was being poured in. I then took a piece of beef, of about half-an-
ounce in weight, cut directly out of a larger piece, so that it should
not be brought into contact with the atmosphere more than was
possible, and placed this in the second prepared vessel, keeping this
covered as before. I then took a saucepan half-filled with water,
into which I placed two of the vessels, keeping them carefully
covered all the time with stout paper covers, leaving a long curtain
of paper reaching half-way down the vessels, so that what air got
into the vessels must make a circuitous route. I then boiled the
contents of the vessels for fifteen minutes, when the liver had nearly
all become disintegrated, and the beef had begun to break down,
and -was giving off masses of flocculent matter, both making a more
or less coloured infusion. Night having intervened between the
boiling and the examination, but at nine o’clock the next morning
I found each infusion tolerably clear, the colouring matter having
become deposited at the bottom, and each infusion was covered with
a thin pellicle, which was filled with minute points of the disin-
tegrated liver. The molecules of the liver were, as a rule, smaller
than those of the beef; but in the liver I observed, beside the
molecules, some larger bluish-looking cells, about y51,,th of an
inch long ; I also observed a few in the beef (Fig. 2). The molecular

m2

260 Experiments on Moning igopeps
mass in the pellicle of the beef infusion had already begun to
assume a definite form. (See Fig. 2.) After this I saw no great
change in this, except that it followed closely in the wake of the
transformations of the molecules of the liver, and which will now
claim our special attention. ‘The contents of the third vessel,
which contained an infusion of fish, will be alluded to farther on.
On the third day the principal portion of the molecular mass had
arranged themselves into long tubular lines, the tubes being formed
of a very thin transparent film (Fig. 3). This protoplasmic and
structureless substance is very remarkable, and is found in all the
infusions that I have as yet had under experiment, and in this
the greater part of the molecules are seen to be imbedded; and it
appears to me that this is what is acted on by the forces before
mentioned, and which becomes moulded into the various forms that
more or less approach some of the recognized animalcules.

‘The substances which we are discussing appear to me to divide
themselves naturally into four divisions; thus, first we have the
molecules; secondly, we have the structureless substance; thirdly,
we have the oil-globules, or cells; and, fourthly, we have what
appear to be vegetable cells, or spores of some mucedinous plant.
The latter were so distinct that it would be impossible to confound
them with anything else seen in the infusions; and from their
being found in the flocculent matter, and also imbedded in the film,
as seen attached to the piece of liver at the bottom of the vessel, I
do not believe them to be obtained from the atmosphere. On the
fourth day the oil-globules were very numerous, and varying from
reooth to tstocth of an inch in diameter, each having a double wall;
the interior was entirely filled with what appeared in the smaller
cells to be a grumous mass, but the larger cells showed what this
really was, namely, a mass of cells, and these again were filled with
smaller cells, and so on, until they were lost to view (Fig. 4); so
that one large cell contained many generations of cells.

The next day these larger cells had burst, and their contents
had formed themselves in long, moniliform, decussating lines (see
Fig. 5), and from a group of these I observed another, and quite a
distinct growth, had sprung, agreeing in the manner of branching
to a plant I shall next have to mention. The mycelium-like
threads measured about gooth of an inch in diameter, and they had
just the appearance of the mycelium of some fungus. I tried to
find the nucleus or spore from which these mycelia had sprung, but
I could find none. ‘The only thing I observed was, that they
appeared to me to spring from this group of cells. Both these
groups of cells had a yellowish-blue colour, I presume from the
refracted light.

On this same day (the fifth) of the experiments there appeared
at the bottom of the infusion of the liver a remarkable plant (Fig. 6).

ete Noe oS. Spontaneous Generation. 261

It sprang from a small piece of liver lying at the bottom of the
vessel. This grew from a very small speck when first observed to
six lines in height by the seventh day. The filaments of which
the plant is composed are hollow, and with the highest magnifying
power I, could apply I could observe no cellular structure. It
branched in a dichotomous manner, and the tubular stems were
filled more or less with a grumous mass, very thick towards and at
the base, but gradually lessening in mass and density upwards,
so that the apical portion of the main and lateral branches
appeared free and transparent. ‘The diameter of the principal
branches was about z/5pth of an inch in diameter. This plant grew
very rapidly until it nearly reached the top of the infusion, and at
this time I clearly saw that it belonged to the genus Leptomitus,
and that it was very nearly allied to L. lacteus, only that it was
not constricted at the joints or septa. I shall name this plant
provisionally Leptomitus ktisma. On the 12th day it had reached
the top of the infusion. The exposed portion turned to dull pale
olive green, and reflected a bluish tint, and when I took some of it
up to examine it, the portion so taken seemed to me to be entirely
alive with moving elliptical bodies, measuring from the +g}ooth of an
inch long, and graduating down to the most minute point. These
were exceedingly active, moving about in all directions, When
seen singly they appeared of an opaque white, but seen en masse
they had a pale olive-green colour. I observed that here and there
one might be seen longer than the others, as if two or more had
become fused together. These would all of a sudden start off across
the field of view, driving any that might happen to be in their
way aside; and when they had full room to move, would swim
with a whirling or gyrating motion.

On the sixth day I observed a curious growth, apparently
springing from one of those bluish-looking sporules before men-
tioned. These have somewhat the appearance of some of the asci
of the genus Peziza or Ascobolus—compressed, clavate, but con-
stricted between the sporules, the fronds measured ¢55th of an inch
long. I only saw this one group, and therefore cannot say what
it really is. It is probably a plant in an incipient form, but I
know of nothing like it amongst British plants (Fig. 7).

The eighth day revealed a very curious and interesting develop-
ment ; not exactly a plant, but a number of elliptical cells appeared
imbedded in an inflated bubble, caused, I presume, by the generating
of some gas from a piece of liver lying at the bottom of the vessel :
the rest of the liver was also covered with a film protoplasmic
substance. ‘These cells were very evenly scattered over the bubble
(Fig. 8). A few of them had united and become more elongated,
and one or two had either had others attached and become fused
together, or a long cell had thrown out a short branch at right

262 Experiments on ee eee
angles to the larger or parent cell. The average length of the
single cells was about ¢o55th of an inch long. How these cells had
become imbedded so evenly in this film, or how they came there at
all, at the bottom of the infusion, I cannot imagine: I do not
believe in their having come from the atmosphere. The surface
pellicle at this time was swarming with the so-called bacteria and
vibrios, in different stages of development.

From this up to the fourteenth day I observed no particular
change, but now the vibriones had become much elongated, similar
to those figured by Dr. Hughes Bennett, in ‘ Popular Science
Review,’ page 53, Fig. 2.

The beef infusion had at this time developed plenty of bacteria
and vibriones, and three large patches of Penicallium crustacewm,
which occupied nearly all the surface of the fluid, but no other
plants were observed in it. ‘This plant did not make its appearance
at all in either of the other vessels.

Fifteenth day the pellicle of the liver showed several dense
patches of cells, varying very much in size, and of various forms,
the smaller ones being generally spherical, and the larger ones
more or less angular, the larger being filled with cellules in various
stages of development. This was almost the first bright or sunny
morning since the commencement of the investigations, and the
vibriones were exceedingly active, moving about in various direc-
tions, and gyrating, reminding one very much of the gambols of
Gyrinus natator.

Sixteenth day I observed imbedded in some flocculent matter of
the liver, suspended near the bottom of the vessel, some curious cells,
very much like the nucleous bodies found in the sarcode of Gromia,
as figured by Schultze and Carpenter. The large cells were filled
with a molecular mass, in various stages of development into cellules.
In the large pedunculated cells it will be seen that the molecules
have arranged themselves somewhat into lines, particularly towards
the peduncle, and gradually developing upwards into cellules ;
the lines of demarcation could be just discovered (Fig. 9). In the
spherical cell these lines were rendered more distinct, the cell
having apparently reached a higher state of development. The
development of cell structure from the molecular mass was seen to
great advantage in these large cells, better perhaps than from the
larger masses of molecular matter. We first observe the enclosed
molecules are being acted on by some force or forces as they begin
to arrange themselves into various groups, drawn together into
centres, and consequently the lines between these centres are ren-
dered clear and transparent, and from these it would appear that
the protoplasmic film grows, and envelops the nucleus of mole-
cules. Ina short time the molecular mass in these enclosed cells
also begins to divide in a similar manner. So the development goes

Pe ee apleal Spontaneous Generation. — 263

on, dividing and subdividing, and at the same time the continuation
of life.

The 17th day was cold and dull. I could not discover anything
different from what I had seen before.

On the 18th I observed some of the highest developed forms
that have yet been discovered, either by M. Pouchet, Dr. Hughes
Bennett, or, so far as I have seen, any one else. M. Pouchet
describes this, or a form figured by him which I take to mean the
same thing as this, to be the ova of Paramecium. At first I
observed a number of groups of molecules collected together into
various shapes, and some appeared in the act of dividing, or as if a
larger and a smaller had joined together (Fig. 10). Hach of these
groups was enveloped in a proligerous membrane, and at a little
distance from this was to be seen another membrane, and these
again were attached, or rather imbedded, in another free one, which
outer one was thickly studded with molecules of matter, and the
whole infusion was swarming with vibriones, which appeared larger
than I had before seen.

We now come to some remarkable forms, which appear rather
more advanced than those figured by Pouchet, and copied by Dr.
Hughes Bennett ;* but if they be the same, only in a different
position, I have found that what Pouchet took to be a nucleus is
in reality an orifice. In this case they would come very near to,
if not identical with, Prorodon niveus ; but these are more pyri-
form. But I could not detect the toothed mouth, or the polygastric
system (Figs. 11,12). These organisms were constructed of the
protoplasmic film, thickly studded with molecules, which latter
were rather larger than the generality, and were more sharply
defined. It will be observed that the orifice of one of the specimens
is at the larger end, whereas in the others it is at the smaller end.
These specimens measured about y¢4p 9th of an inch in their widest
diameter. One specimen I observed quite different from the rest.
The protoplasmic film had rolled itself round a long axis, and
formed an orifice very much like the genus Stentor, and which this
specimen also reminded one of in its elongated form (Fig. 11).
The molecules imbedded in the film forming this organism were
arranged, more or less, in longitudinal lines. This measured 5)'p9th
of an inch in its widest diameter, by y53-y,th of an inch long. I could
not discover any movement in these, either ciliary or otherwise.

On the 20th day we arrived at the highest development in the
direction of animal life that I have been able to obtain; that is, if
we except some very remarkable vibriones that I observed on the
38th and 44th days. This, as will be observeed, is a hollow ellipse,
and is formed of the protoplasmic film, and is rather sparsely studded
with what appeared like very minute tadpoles (Fig. 13). This

* ‘Popular Science Review,’ fig. 5, p. 55.

264 Haperiments on “Journal, Nov. 1, 1869.

form agrees very nearly with the genus Sphaerosira volvow, as
figured by Pritchard (edit. 1842, t.1, Figs. 48, 49). The proto-
plasm in which these animals were imbedded had a faint reticulated
appearance, which would make it rank nearer the genus Volvoz,
and the animals could be seen waving and wriggling their tails
between the meshes. Vibriones were at this time very abun-
dant, and amongst them I observed a number of white, spherical,
transparent bodies rolling through the fiuid—just the kind of
movement one sees in Volvow globator. ‘These I believe to be
Monas umbra, as they agree in size with that species, sziooth of
an inch in diameter.

Dr. Hughes Bennett says: “It frequently happens that, soon
after some of these higher infusoria are seen, the pellicle falls to
the bottom of the fluid, where it constitutes a dense precipitate,
and slowly breaks down; then another scum forms on the surface,
and molecules, bacteria, and vibrios are again produced.”

“The varied forms produced are spoken of by Ehrenberg and
other naturalists as being different species, but I think it will be
found that the laws, not only of molecular, but of alternate genera-
tion and parthenogenesis, prevail among them, and one frequently
passes into another.’* But a little farther on he says:—* In all
cases no kind of animalcule or fungus is ever seen to originate from
pre-existing cells or larger bodies, but always from molecules.”

The various forms as spoken of by Ehrenberg might, under
certain conditions, constitute what we are pleased to call species ;
but we have only seen them under one condition, and that one con-
dition has revealed these forms very distinctly, as distinctly, in fact,
as many so-called species, and, so far as we know of them, they seem
equally entitled to rank as such. Could their existence be pro-
longed, and could they be placed in more genial media, the pro-
bability is that we might see them develop into other forms. In
one instance I tried this by taking what M. Pouchet has described
as the perfect ovum derived from the molecular mass. I placed it
in a watch-glass half-filled with water, and covered with a bell-
glass; but, at the end of a fortnight, I could discover no permanent
or particular development, only that the molecules had become
slightly larger. But there is one thing to be observed here, the
specimen might not have been placed in its proper medium, and it.
might not have been supplied with proper nourishment for its
further development. It would therefore be wrong to say that this
microcosm had reached its ultimate form. The great fact then is,
that we can to a certain extent see the beginning, but we cannot at
present see the end.

On the 22nd day some curious and beautiful forms revealed
themselves. I observed five of them in a group, varying in size.

* ‘Popular Science Review,’ pp. 55, 56. 1869.

Monthly Microscopical ; ; =n ‘
pygutiel Noy. 1, 1869. Spontaneous Generation. 965

The largest measured +$3oths of an inch across. They were tinted,
of a pale-green colour. The periphery was double, like an olea-
ginous cell, and the molecules radiating very regularly from the
centre, and it appeared to me to be formed like a concavo-convex lens,
or hollow or concave on one side and convex on the other. What
this really was I cannot tell, as this was the only group or specimen
that I have seen, and I know of nothing like it (Fig. 14).

23rd day.—We now come to a very curious vegetable growth,
springing from what appears to be only an irregular oleaginous
cell; for I could not discover with the most careful investigation
anything like a true vegetable cell enclosed in the oil-cell, and I
have had: opportunities of watching the growth of this from its first
appearance, as the plant has been very frequent in the liver infusion,
but I saw nothing of it in the beef (Fig. 15). |

The plant first appears, as I have endeavoured to delineate it, in
attached or free fusiform slightly-curved sharp-pointed fronds. They
arrange themselves with their convex sides together, and they have
then just the appearance of that curious Desmid Ankistrodesmus
faleatus, Corda, and to which this seems nearly allied. On the
34th day I noted a large mass of this plant ; it had then attained
to the =1,th of an inch high, and the fronds of which it was composed
measured about zy45oth of an inch. It had a very remarkable appear-
ance, and reminded one somewhat of the marine plant Sphacellaria
scoparia. I observed that the young fronds of this plant when
found free in the protoplasmic film are at first quite colourless.
They afterwards attain to a pale olive-green tint, and when full
grown to an olive-green. I have given the name of Chlorocyclos
fasciatus to this plant, which means a bundle of green semi-circles
Cie 9). | |

From the 23rd to the 26th day I did not observe any parti-
cular change, or any further development ; but on the latter day I
observed a group of cells, varying in size, the largest measuring
+3soth of an inch in diameter. Each was divided into four divisions
by broad dissepiments, each being provided with a double wall.
They were of a delicate green colour, and reminded me very much
of the cells in Ulva erispa (Vig. 16).

On the 34th day the beef had developed some rather different
forms to those of the liver, and particularly some masses of angular
cells, imbedded in a transparent film. ach angular fragment or
cell had a distinct round or elliptical nucleus; some of the larger
had two. These angular cells are crowded with molecules, except
the nucleus, which is free. The beef appears to me to break up
into these angular cells; for when a small bit was placed between
slips of glass, and pressed, it broke up into little tessera, each being
held together by a transparent film. (See Fig. 18.) These cells vary
in size from the +,2;,ths to =?,ths of an inch in diameter.

266 Experiments on ne Won ana?

On the 38th day the vibriones had attained to a large size, and
were three or four jointed, most of them having a large globose
head; and I observed that the portions between each articulation
were slightly curved, having a faint bluish tint. Professor Clarke,
in his investigations into the structure of muscle and muscular
fibre, says, although with great reluctance, he must admit the
truth of what he has seen, and that is, he has observed portions
of muscular fibre, or the fibrilla, break away from the mass and
Swim away as vibriones. So that in fact the common muscular fibre
of our and other bodies appears to be only collections of vibriones,
remaining in an inactive state until liberated by the decomposition
of the matter holding the vibriones together.

Now the fibrillee of portions of muscle that I have examined
from the liver of a fowl give me just the idea of vibriones being
packed together transversely: they are the same in colour, the
same in measurement, and the articulations are the same distance
apart, and I believe it would be impossible to separate the free
fibrillee from the vibriones. I have myself seen two or three
fibrillee partly berated from a piece of muscle moving about in
the same manner as the vibriones ; but when all the infusion is a
mass of life, I could not positively say that what I saw was volun-
tary motion. At the same time, I feel convinced in my own mind
that it was so. ;

I now come to the last group to which I have to draw atten-
tion, and these are some very remarkable vibriones. Generally
speaking, these animals are simple—one to three or four articulated
cylindrical creatures; but though the greater part of those in the
infusion were simple, there were also amongst them a great many
branched forms; some of the most curious I have sketched here
(Figs. 20, 21, 22). These were observed rolling and tumbling
about the fluid in a very remarkable manner. ‘They were all tinted
of a delicate blue colour, and those that I have sketched measured
from yo'xaths to +,%;oths of an inch long. In the earlier stages of
vibrionic life they are without the rounded heads; they seem only
to take it upon themselves to wear heads at all towards the latter
part of their lives. Some I observed in the beef imfusion on the
52nd day had monstrous heads, belonging evidently to the Macro-
cephali. Some had two heads, one at each end; but these, I pre-
sume, would divide at the septa, and form two animals.

I will conclude with relating the experiment I prosecuted with
the third vessel that I mentioned at the commencement of this
paper. I began, June 8th, at two p.m., by taking a thoroughly
clean glass vessel, and scalding it with boiling water. I then took
out a piece of mackerel from the most fleshy part of the back
towards the head; I carefully turned back the skin so that the
part I took should not have been brought into contact with the air

Adie Nov. 1, 1260. Spontaneous Generation. 267

or water in washing. The mackerel from which the piece was
taken was brought directly from the oven, cooked, ready for eating.
The vessel was kept carefully covered from the first, so that nothing
should fall into it. Some boiling water was poured upon the piece
of fish to the depth of about an inch; this was then stood on the
top of the kitchen hot-plate, which, I must say, was nearly red-
hot; it was left in this position for nearly an hour, when I con-
sidered it had had quite cooking enough. It was then left to cool ;
and it was all this time kept carefully covered with stout paper, and
tied down. At six o’clock I examined some of the oleaginous cells
in the thin pellicle that had formed on the surface. Some of the
cells were round, others ovate or elliptical ; the latter showed two
very dark bands, one broad one near the middle, and the other near
one end (Fig. 23). At this time I could not discover any life in
the vessel ; at the same time, I do not say it was not there.

At nine o'clock the next morning the whole infusion was a mass
of life. very particle that had been liberated in the cooking and
heating afterwards, and they were very numerous, appeared to me to
be endowed with life, that is if we are to regard animated microscopic
matter endowed with voluntary motion as contaming the property
termed life. They appear only as animated cells, some of which
were spherical, and others elliptical; the latter had each a central
nucleus, like a well-defined rmg, the centre of which was trans-
parent. The spherical bodies measured from geooth to ttooth
of an inch in diameter, and were what I believe are called Monas
crepusculum (Fig. 24).

The fibre of which the flesh of the mackerel is composed, when
highly magnified, is seen to be transversely striated, very much like
the fibrilla of muscle alluded to before. ‘These fibrille break up,
where these transverse strize are observed, into minute elliptical
dises or cells; and it appeared to me that directly they were set
free they moved away with a very rapid motion, the same as the
little monas mentioned above.

The oleaginous cells have not been less active, for some of these
had by the 10th developed a vegetable growth of a very similar
character to the leptomitus in the liver ; but it was not the same
(Fig. 25). In one cell will be observed another plant beginning
to grow ; it has not yet penetrated the walls of the cell (Fig. 26).
I could not in this, or any others, discover anything like a vegetable
cell, or sporule, and the growths always seem to me to spring from
one side.

There were immense numbers of spherical oil-cells in the pellicle,
and many of them had arranged themselves into little moniliform
masses. ‘These oil-cells are provided with double coats, the inner
one reflecting a beautiful purple colour.

There were also great numbers of elliptical cells imbedded in

5 Monthly Mi j
268 Spontaneous Generation. _ [ Monthly Microscopical

the proligerous pellicle; these had a yellowish colour, the cells
being so numerous as to appear like an intricate network (Fig. 27).
These appeared to me to be the same as had broken away from the
fibrillee of the flesh, the same as Fig. 6.

On the 12th the molecules, which are quite distinct from the
cells before spoken of, had arranged themselves into those oviform
masses described by Pouchet, and the same as I have seen in both
liver and beef (Fig. 29). I also observed to-day several fine
thread-like filaments of a bluish colour, having just the appearance
of much-elongated vibriones (Fig. 28).

From very careful watching of this infusion it appears to me
that the oleaginous cells are in themselves capable of producing
these vegetable growths; for I have carefully examined this in-
fusion, to see if I could detect anything like a sporule or vegetable
cell, and have failed to do so; and yet in about forty-eight hours
after the infusion was made, and had passed through such a fiery
ordeal, plants were developed, and grew with great rapidity.

In conclusion, I must say that I conducted all my experiments
with the greatest care, so as to prevent and protect myself against
objections that I am fully aware might be raised against such ex-
periments. There is one thing which must strike every one that
has paid attention to the experiments prosecuted by the various
naturalists, and that is that we all obtain very nearly the same results
at all seasons of the year. Whether it be in France, Scotland, or in
Devonshire, the same animals are developed, the same movements
and the same formative processes go on in the molecules, whether
they be of fish, flesh, or fowl. ‘The same laws are ever and con-
stantly at work, as well in the laboratory, in our rooms, and in the
open air. And so far as all our experiments have carried us, we
have seen that life resides in the most minute atom that our instru-
ments are able to detect, and with the same force in proportion to
its size as that of the most ponderous creature that inhabits the
globe, and yet we cannot cry, Eureka. The great mystery of
mysteries remains the same.—Paper read before the Devonshire
Association for the Advancement of Science, July.

Monthly Microscopical ; 2
ROmREEL Now. 1. 1869. Mounting Entomostraca. 2.69

IV.—On Collecting and Mounting Entomostraca.
By J. G. Tarem.*

In this paper I propose, as shortly as possible, describing the
methods employed by our late friend and member, Mr. Clayton, in
collecting and preparing Entomostraca for microscopic examination,
and it must be a matter of sincere regret to every one of us, that
he has not survived to make the promised communication, and
gratify that eager curiosity, which the neatness and brilliance of
such objects, as mounted by him, so generally evoked.

It is needless to remark, that wherever water exists, containing
organic matter passing into a state of decay, these active little
scavengers will be met with, in greater or lesser abundance and
variety ; even the plash left by the summer shower, and remaining
unevaporated for a few hours, may afford them. Various modes of
capture must be pursued according to locality. ‘To obtain the
free-swimming oceanic species, we have obviously no other resource
than the muslin tow-net, while there is practically no better means
of securing the littoral species than by the collection of filamentous
algee, in which they harbour, from the rock pools, rising them in
a basin of fresh water, and on subsidence, selecting the dead speci-
mens. From the ponds and ditches, what may be called the bag
and bottle net, is by far the most convenient and efficient imple-
ment for obtaining them. This consists of a ring, five or six inches
in diameter, screwing into a staff, to which a conical bag of crinoline,
or some other material readily permeable by water, is attached, a
draw-string in the apex securing a short wide-mouthed bottle firmly
by its neck. ‘This net, insinuated under floating weeds or the
vegetation which borders and rests upon the water, and slightly
shaken, disturbs and intercepts the Entomostracans in the act
of sinking to the bottom for safety. In bright sunny weather,
however, when they are found in greater numbers sporting on the
surface, or in the warmer water of the shallows, a long narrow-
necked vial (a ten-drachm one answers sufficiently well), fastened
by an india-rubber loop to the staff, dipped just below the lip, and
the water allowed to flow gently in and fill it, will be found more
effective. In either mode of proceeding the contents of the bottles
may be run off through a Wright’s collecting-bottle, until a
sufficient supply is procured. JI may here take the opportunity of
mentioning a small improvement on Wright’s bottle, effected by
attaching a fan-shaped, curved plate of metal, to the entrance-tube,
so directing the current of water against the muslin which covers
the mouth of the outflow tube, as to prevent that accumulation of
sordes upon it, which occasionally impairs its utility.

* Communication to the Reading Microscopical Society, October 19th.

270 Mounting Entomostraca. — [Mpg Watoseapieal
It should be borne in mind, that some species of Entomostraca
are strictly local, limited even to a small part of a particular pool.
Daphnia mucronata, for example, will be obtainable by hundreds,
from the space of a very few square yards, whilst but a solitary or
perhaps not a single specimen will be found beyond the well-defined
area. In such cases, local knowledge can alone avail the collector.
_ The Entomostraca thus secured should be picked out under the
dissecting microscope, transferred to watch-glasses of FILTERED
water, and allowed to remain for twenty-four hours, in order that
the contents of the laden intestine may be discharged, some of which
if this precaution be not taken, would, under the pressure of the
covering glass, inevitably be squeezed out, and sully the mount ;
drawing off the water, a little spirit of wine speedily deprives them
of life; and all dirt having been removed by the aid of a camel’s
hair pencil, they are to be placed in a few drops of diluted medium
(half medium and half water) on a glass slip, protected from dust,
until saturation 1s complete, and not until then, put up in the me-
dium ; shallow cells being mostly necessary.

After many and repeated experiments, attended with variable
success, Mr. Clayton found Mr. Farrants’s modification of his
medium, by the omission of the arsenic, and the reduction of the
elycerine to a minimum, on account of the known effects of that.
fluid in slowly dissolving the carbonate of lime of shell, gave the
best results, in the greatest amount of transparency and permanence
of which such subjects are susceptible. The receipt is as follows :—
Gum arabic (picked), 1 0z.; distilled water, 1 oz.; glycerine, $ oz.
The gum to be dissolved in the water, the glycerine added, and the
whole filtered through white blotting-paper previously moistened
with distilled water. 3

In giving this brief account of the late Mr. Clayton’s practice,
I can only express the hope, that some of our members, through
the information now afforded, may be induced to emulate that
manipulative skill which made his preparations unrivalled as yet
in excellence, and that through them, his endeavours to preserve
the Entomostraca as permanent objects for the microscope may be
carried to a still higher degree of perfection.

&

thly Mi i
Teer. Ni Be theo. ( 271 )

PROGRESS OF MICROSCOPICAL SCIENCE.

The Movement of the Protoplasm in the Cells of Anacharis alsinas-
trum.—Under this title a very valuable paper of 26 pp. appears, by
Prof. J. B. Schnetzler in the Archives des Sciences for September 15.
The author goes into the history of the observations made upon the
plant, and then details a number of experiments, made with a view to
determine the different effects produced on the movement of the pro-
toplasm, by heat, light, electricity, and chemical action. In his
opinion light and heat have most to do with the motion. The most
refrangible waves of light have the greatest influence, but heat seems
to be the all-powerful agency. Electricity has its own action, but not
an extensive one, while gravity seems to have little or nothing to do
with it. The author thinks that we have here a marked example of
the conversion of heat and light into mechanical motion.

The Structure of Nerve-tissue generally.—A useful review of recent
labours on the histology of the nervous system will be found also in
the above journal. It is possibly from the pen of M. Claparéde.

Tenia cucumerina.—M. N. Melnikow, of Kasan, contributes an
account of this cestoid to the Archiv fiir Naturgeschichte (Heft 1, 1869).
He gives three figures of the worm, and refers to the labours of Van
Beneden, Leuckart, and Cobbold.

The Structure of the Mucous Villi.imHerr Dr. Th. Eimer, of
Wurzburg, has contributed a lengthy physiological paper on the
subject of the absorption of fatty matter by the villi to Virchow’s
Archiv (Band 48, Heft 1). In this he describes the structure of
these mucous processes, both in fresh specimens and in specimens
prepared with osmic acid, chromic acid, and other substances. The
sketches of the structure which he has given are most elaborate, and his
researches tend to show,that fats are absorbed through the connective-
tissue system of canals lying in the mucous membrane. ;

The Arrangement of the Outer Nervous Layer of the Cerebrum.—Dr.
Rudolph Arndt’s researches in this structure reveal a complexity of
construction not dreamed of a few years since. It would be impossible
to attempt an abstract of his results, which occupy nearly a sheet of
the journal in which they are published.—Vide Archiv fiir Mikro-
skopische Anatomie, 5 Band, 3 Heft. Various other papers of import-
ance on the structure of the nervous system appear in this journal.

The Anatomy and Development of the Reproductive Apparatus of
Lymneus.—This is a very interesting and painstaking account of the
construction and development of the generative system of an air-
breathing mollusk; and is illustrated by some very good sketches.
It does not, however, decide the question as to the well-known
hermaphrodite gland.—See Siebold and Kolliker’s Zeitschrifti, 19 Band,
3 Heft, issued September 6.

272 PROGRESS OF MICROSCOPICAL SCIENCE. [Monthly Microscopical

The Development of Insects.—In the preceding valuable journal will
also be found an excellent paper, by Herr Ganin, on the development-
history of Insecta. The author deals principally with Platygaster,
Polynema, Teleas, and Ophioneurus, and gives about seventy exquisite
illustrations in three large folding plates.

Tactile Corpuscles in the Parroquet’s Beak.—Dr. E. Gougon has a
curious paper on this subject in the Journal de Anatomie for October.
He gives a section of the beak, showing what he regards as groups of
Pacinian corpuscles, and he gives some figures of these bodies sepa-
rately examined, which seem to bear out his assertion of the existence
of these corpuscles. The author admits that there are difficulties in the
way of accepting this view, but he thinks that the fact that the parro-
quet uses its beak as a tactile organ is sufficient to obviate them.

Our Knowledge of the Retina.—Professor Krause, of Gottingen,
gives a sort of critique of the work done on the retina from the year
1856 to 1868, in the above number of the Journal del Anatomie. It
will be found a valuable retrospect for those engaged in the histology
of the eye. It was begun in the previous number, and will be
continued in the next. It analyzes the views of the author, of
Schultze, Hulke, Zenker, Valentin, Babuchin, Steinlin, Miller, Henle,
and others.

The Latex-fluid of the Mulberry. — Great difference of opinion
exists as to the nature and uses of this curious fluid, and of the system
of vessels by which it is conveyed. In a paper published in the
Annales des Sciences |t. x.|, M. EH. Faivre discusses the opinions of
Schultze, Trécul, Naudin, Von Mobl, and others, and concludes by
regarding the latex as a nutritive fluid, an elaborated sap, conveying
materials for growth. It may contain other matters also, but it is
not on that account to be regarded as excrementitious,

A Sea-deposit destitute of Foraminifera.—Myr. Charles Bailey, who
has been examining the foraminifera sands of Connemara, recently drew
attention to the fact, that while examining some sands in Dog’s Bay,
Connemara, he found a deposit in a small creek on the southern
shore of the bay, which, from its being sheltered by rocky sides, he
felt sure would yield foraminifera. On a minute examination, how-
ever, of the materials composing its beach, there was a singular
absence of foraminifera, scarcely a single example of these creatures
being discoverable. The beach was uniform in character from low-
water to high-water mark, and was for the most part made up of
fragments of molluscous shells mixed with coarse grains of sand.
This deposit is the more remarkable from the contrast it presents to
the rest of the beaches in the neighbourhood, those of Dog’s Bay and
Gorteen Bay being made up of considerably finer materials and
abounding in foraminifera; further, the most perfect specimens of
foraminifera are found round the next headland, not many yards from
the creek in question.—See ‘ Proceedings of Lit. and Phil. Soc. of
Manchester,’ issued in October.

The Microscopical Examination of the Dog-woods.—In ‘'The Student’
for October, Mr. J. R. Jackson, in a paper on the dog-woods used for

Metal, Novi 19, | PROGRESS OF MICROSCOPICAL SCIENCE. 273

making gunpowder, has given an illustration of the practical use of
the microscope in diagnosing the different forms of stems. He has
given the characters of the sections (transverse) of different species,
and has delineated them in a handsome plate.

The Embryogeny of Crustacea.—M.. Edouard Van Beneden continues
his inquiries on this interesting subject. In his last memoir, which
he has reprinted from Bulletin de V Académie Royale des Sciences of
Belgium, No. 8, 1869, he deals with the development of Mysis,
selecting M. ferruginea as a type. A 4to plate contains several
figures illustrating the different phases of the ovum, from the time
when the embryonical development has hardly begun, up to the date
when it has undergone all the development that takes place within
the egg. He thus sums up his conclusions :—-(1) The blastoderm
is formed in the course of a partial segmentation of the vitellus. (2)
The cellular zone, which results from the multiplication by division
of the cicatricule, extends itself over the whole surface of the egg, to
form a closed blastodermic vesicle, before any trace of organs is seen.
(3) The division of the embryo into a cephalic and a caudal lobe
results from the division into two lamine of a primordial cellular fold,
which may be compared to the cellular column [Keimhiigel] of
Hemiptera, Orthoptera, and Lepidoptera. The identity of formation
of these organs, which have evidently the same morphologic value, and
the perfect analogy between the phenomena which subsequently take
place in the cephalic lobe in the crustacea on the one hand and the
insects on the other, are in my opinion facts which enable us to
determine with ease and certainty what are the homologous organs in
these two groups of Arthropoda. (4) The caudal appendage of
Mysis is folded under the abdomen as in all Decapods. (5) The
caudal lobe commences to be formed before it is possible to recognize
the least trace of antennary appendages; these appear at the same
time as the mandibles in the form of simple cellular papilla. (6)
The Nauplian cuticle is formed at once over all the surface of the
embryo; it is the first embryonic cuticle. Mysis does not undergo
a blastodermic moult. (7) The tail, which is bifid in some species
(M. vulgaris and M. chameleo), is simple, and terminates in a cul-de-sac
in other species (M. ferruginea).

Regeneration of the Spinal Cord.—In a recent series of researches
on frogs, MM. Masius and Vanlair have arrived at certain conclusions,
which are thus expressed by M. Th. Schwann in his report to the
Belgian Academy. (1) The spinal cord in the frog repairs the
destroyed tissue by means of a new medullary tissue. (2) The return
of the functions which had been previously suspended coincides with
this repair; and (3) In reproducing the structure, cells precede fibres
in course of development.—Bulletin de PAcadémie Royale de Belgique,
Meet: 1869.

The Development of the Crystalline Lens.—M. Woinow, of Moscow,
recently presented a memoir on this subject to the Vienna Academy
of Science. It has not yet been published in full.—L’ Institut, Oct. 13.

The Structure of the Cerebellum.—Herr Obersteiner publishes a

VOL. II. U

274 PROGRESS OF MICROSCOPICAL SCIENCE, [Monthly Microscopical

paper on this subject. He says that we may distinguish in the cere-
bellum of the infant five layers, one of the character of connective
tissue, and the others of nervous substance. The cells of Purkinje
exist at that period in the fourth layer. In the fully-formed cere-
bellum we distinguish the basal layer, the exclusively grey layer, the
universal cellular layer, and the rusty-coloured layer. Purkinje’s cells
present some differences, according as they are situated at the summit or
bottom of a convolution, and notwithstanding their innumerable rami-
fications of extreme fineness, all the processes of the same cell extend
in a plane vertical to the longitudinal direction of the bourrelet. Both
cells and their processes bear characteristic strie.—L’Institut, Sep-
tember 22.

The Fossil Bryozoa of Bessarabia formed the subject of a paper
presented to the Academy of Science of Vienna, at the meeting held
in June, by Herr Reuss. Some of the Oolitic deposits of a porous
character, and composed in great part of shells, enclose the remains
of Bryozoa in large quantity. The author found four species, two of
which—Hemieschara variabilis and Diastopora corrugata—were remark-
able by the extreme variety of their forms.

Tuberculous Deposit in the Tissues.—The eleventh report of the
Medical Officer to the Privy Council contains a most admirable
paper (of great length) by Dr. Burdon-Sanderson on his experi-
ments in inoculating tuberculous matter. It is illustrated by a
multitude of beautifully-tinted lithographs, showing specimens of
various tissues containing the tubercular material as an interstitial
deposit. It is most creditable to Mr. Simon that such good work
should be done in his department. ;

Nobert’s Lines Photographed—The last number (September) of
Silliman’s ‘American Journal’ contains a brief paper on the above
subject by Col. Woodward. As the facts have, however, been already
brought under the notice of the Royal Microscopical Society at its
last meeting, in a paper which shall appear in our next issue, it is
unnecessary to refer further to the matter.

Rain-water wnder the Microscope.-—-‘ Scientific Opinion ’ (October 13)
has extracted with illustrations some remarks of Dr. Angus Smith,
F.R.S., on the microscopical examination of rain deposits. The
subject may be of interest to certain of our readers.

Cells within Cells—In the notes to his French edition of the
‘Fertilization of Orchids, which Mr. Darwin has recently prepared,
he gives the following account of his attempts to enumerate the pollen-
grains of one flower :—“I have endeavoured,’ he says, “to estimate
the number of pollen-grains produced by a single flower of Orchis
mascula. ‘There are two pollen-masses; in one of these I counted
158 packets of pollen; each packet contains, as far as I could count,
by carefully breaking it up under the microscope, nearly 100 com-
pound grains; and cach compound grain is formed of four grains.
By multiplying these figures together, the product for a single flower
is about 120,000 pollen-grains. Now we have seen that in the allied
O. maculuta a single capsule produced about 6200 seeds; so that there

Mourns, Not tes | PROGRESS OF MICROSCOPICAL SCIENCE. 278

are nearly twenty pollen-grains for each ovule or seed. - As a single
flower of a Mawzilaria produced 1,756,000 seeds, it would produce,
according to the above ratio, nearly 34,000,000 pollen-grains, each of
which, no doubt, includes the elements for the reproduction of every
single character in the mature plant !”

The Microzyme of the Blood—MM. Béchamp and Estor have
been experimenting on the coagulation of blood and studying the
phenomena with the microscope, and they arrive at some very
startling results. The Microzyma is according to them a minute
vegetable form, so small that numbers of them are arranged together
in one Bacterium. From the results of their observation of the blood,
they conclude that the fibrine is nothing more than a sort of membrane
(like the vinegar plant, in fact) formed of these microzyme of the
blood accumulated together.—Vide Comptes Rendus, September 20.

Microscopic Investigation of Milk and Blood of Animals with Foot
and Mouth Disease.—In the ‘ Lancet’ of October 23rd, Professor Brown
has given a very elaborate account of his inquiries on this subject.
When the disease is fully developed, about the third day from the
first appearance of vesicles, the milk invariably contains morbid pro-
ducts of a very pronounced character, which were shown in one of
the figures. This specimen was taken from a cow which had been suf-
fering from the disease for ten days. The fluid, after standing for some
time, separated into two parts—a curdy deposit and an amber-coloured
whey. The same elements were found in both constituents—viz,
large granular masses of a brownish-yellow colour, numerous pus-like
bodies, bacteria, vibriones, moving spherical bodies, and a few milk-
corpuscles. It is particularly worthy of remark that these morbid
elements were found in specimens of milk which in their physical
character presented no appreciable peculiarity. In some specimens
which were viewed with the micrometer eye-piece the milk-corpuscles
varied in size from 5,)55th to yp}o5th of an inch in diameter, and the
granular masses from 53,th to yo/y9th of an inch. Milk from animals
affected with cattle plague and also with pleuro-pneumonia was always
found to contain an abundant quantity of the granular masses and
pus-like bodies; and in cases of cattle plague similar elements were
distinguished in the curdy exudation which existed in the mucous
membrane of the mouth, pharynx, trachea, and bronchial tubes. Ex-
amples of milk taken from animals in different stages of foot and
mouth disease afforded very interesting results. At the commencement
the specific gravity fell to 1024-5, and continued to range between the
two numbers until the animal was convalescent, when it rose to 1026-7,
which standard was not exceeded for two months after recovery. The
granular masses and pus-corpuscles decreased in number as the affec-
tion subsided; but in all the specimens examined after the animals
had recovered, they were found scattered here and there among the
milk-corpuscles ; and even in specimens which were examined a month
alter recovery, they were detected. The granular masses were not
found in milk from the same animals two months after recovery,
but even in these specimens a few pus-like corpuscles were present,

u 2

276 PROGRESS OF MICROSOOPIOAL SCIENCE. [outuy, Necroseapical

Two examples of milk taken from cows on the fourth day of the
disease were found to be highly charged with granular masses; the
milk, however, was remarkably rich in quality, having a specific gravity
of 1034, and yielding a large proportion of cream. Diminution of the
quantity of milk is invariably observed during the progress of any
febrile disease ; and in foot and mouth complaint the loss is sometimes
considerable. Cows, when suffering from the worst form of disease,
lose nearly all their milk; but when the attack is mild in character,
the decrease will not be more than one-third of the usual yield. The
average loss in a large dairy while the disease is going through the
sheds will vary from one-third to two-thirds, according to the number
of severe cases. As all the milk obtained is mixed, the worst milk
will be to some extent modified by the addition of that which is less
highly charged with morbid elements, and the whole is further diluted
by the addition of water, which, judging from some specimens obtained
from an establishment where the disease was known to exist among
the cows, is sometimes added to the extent of 40 per cent. Boiling
the milk has been recommended for the purpose of preventing or
lessening its injurious action ; but as a matter of fact it may be stated
that boiling does not alter the appearance of the morbid elements, nor
does it arrest the movements of bacteria in the fluid. No changes of
a specific kind have been observed in the blood of animals affected
with foot and mouth disease. The blood-disecs, when examined im-
mediately after the blood is taken, will be seen to be covered with
projecting peculiar points; but after a short time many of them
resume the normal circular form. The white corpuscles are in
excess, and there are also present minute circular bodies, which move
actively ; but all these phenomena may be observed in the blood
of animals suffering from other diseases. Numerous examinations of
the flesh of cattle which have been destroyed while suffering from foot
and mouth disease have been made at various times; but no important
morbid changes have been detected. In many specimens the peculiar
worm-like bodies, which were found so abundantly in the muscles of
animals dead of cattle plague, have been seen; but seldom in large
numbers. The meat, however, presented no indications of disease,
and, considering that an enormous quantity of such meat has been
consumed during the last four months, it can scarcely be imagined
that the flesh of animals affected with foot and mouth complaint
possesses any deleterious qualities.

The Ratio-micro-polariscope.—In a paper read at a late meeting of
the Quekett Club, Mr. J. J. Field gave the following account of this
instrument, which he has recently constructed, and of its uses :—No
microscopist need look very far through his collection before meeting
with certain structures that altogether refuse to be evidenced without
polarization ; but in such cases even polarized light is of little avail,
unless certain exact conditions, or at all events a very near approxi-
mation to such exact conditions, of the polarized beam in relation to
those structures can be commanded. Indeed, I have repeatedly
observed that when polarized light is employed in a haphazard
manner, it may indeed paint the object with gorgeous bues; but

mal, Nov. 1.1063, | PROGRESS OF MICROSCOPICAL SCIENCE. 277

instead of developing, it too often optically obliterates detail. It is
the aim of the instrument—the construction of which I shall now
describe—to displace this haphazard mode of operating, and enable
microscopists to mete out to each particular structure its own special
needs and requirements. This is what I claim for it, and I believe
that in the hands of those who will take the pains to become practically
acquainted with its capacities, and have patience to vary its combina-
tions until the correct ones be found, it will prove a valuable aid, not
only in study, but also in original research. The instrument consists
of a frame carrying a Nicol’s prism and three plates of selenite. The
prism is arranged in a rotating collar, and the selenite plates above
the prism are fitted into movable cells, toothed around their circum-
ference. At one side of the apparatus there is fixed a metal pillar,
upon which are arranged three toothed wheels, which only move in
unison ; and the toothed selenite cells are so arranged as to size, that
they gear into these pillar wheels, and take motion from them ; whilst,
at the same time, the relation between the wheels is such, that during
one revolution of the first selenite, the second accomplishes two, and
the third three. As a matter of convenience a fourth wheel is added,
cut with the oblique teeth needed to gear into a four-threaded driving-
screw; this latter being the means of giving motion to the whole.
Over the selenites is placed a condenser, constructed on the principle
of a Kellner’s eye-piece, the field lens of which receives the whole of
the polarized beam, and converges it upon an achromatic combination,
so that no diaphragm being needed, the entire beam passes to the
object. Lastly, there is an arrangement by which the selenite cells
can be instantly ungeared, and turned singly with the finger, so as
to have their depolarizing axes set in any relative position that
may be desired at starting; and in order to make every position cer-
tain, and referrible for reproduction at any after-time, each cell is
graduated, and reads from an index on its own bearing. The cir-
cumference of the prism collar is also graduated through a certain
range, and there is a small projecting stud in the upper part of
the apparatus, intended to fit into a corresponding recess to be
made in the sub-stage of the microscope, so as to ensure the apparatus
occupying on every occasion the same exact position. Thus the
whole optical arrangement, when placed for use in the sub-stage,
may always be set at zero; and as a consequence, when once the
exact adjustments for developing any particular structures are
found, they can be recorded, and instantly reproduced when needed.
Now, supposing the selenite plates to be so locked in the driving-
wheels that their positive axes all point to zero, it is clear that, on
turning the driving-screw, so soon as the first selenite begins to
move, the second will be gradually parting company with it; and
the third (as to axia! relation) will be in advance of both; and since
the rotation of each selenite plate corresponds optically (within the
limits of that one plate) to its gradual reduction in thickness,* and

__ * Tt is not intended to be conveyed that the rotation of any single selenite
plate corresponds optically to such a reduction in thickness as to confer upon it
the chromatic range of the spectrum ; but only to such a reduction as is competent

278 PROGRESS OF MICROSCOPICAL SCIENCE. [onthiy Microscopical

all three selenites, starting from zero, can only resume that position
after three entire revolutions, during every portion of which they
are all occupying different axial relations to one another and to the
object, it is manifest that the optical effect must be the same as though
a great number of different thicknesses of selenite had been tried in
succession. ‘Thus, in examining any object by polarized light, it is
only necessary to make three entire turns of the driving-wheels ; and
then, if the exact selenite supplement needed for developing the struc-
ture be within the compass of the zero setting, some position must be
arrived at in which the details sought may be made to appear with the
greatest possible distinctness. Should not this be the case, the selenite
cells are to be ungeared, the plates re-set, with their axes more or less
out of coincidence, and the former operation repeated, and so on. It
will thus be seen that the number of variations this instrument is
capable of producing—variations that may be so conducted as to
create a gradually increasing or diminishing effect in the direction that
appears to be needed, and which variations, starting as they do from
known data and proceeding in known ratio, can always be reproduced
at will, are almost endless. The ratio movement, by spreading out
the depolarizing axes of the selenites in a predetermined order (some-
thing after the fashion of the opening of a fan), enables the observer
rapidly to arrive at an APPROXIMATION to the most perfect optical con-
ditions for viewing any particular structure; and then, in order to
arrive at absolute perfection in the development of the details, nothing
is needed but a little time and patience, to change the setting, tooth
by tooth (in the direction indicated by the previous adjustments), until
further change becomes detrimental.

By a very simple notation, fine positions can be instantly recorded
and afterwards read at a glance; and although many trials are gene-
rally needed to arrive at the finest effects, still, when any adjustment
giving superlative results with any special object is found, such adjust-

to diminish the intensity of its effect from the maximum, gradually onwards to
the minimum, until one of the neutral axes is reached. But in this instrument
there are three selenites, of such substance that in a certain set position, in which
each plate is individually active in the production of colour, white light results, in
consequence of the chromatic interferences mutually neutralizing one another. It
is therefore clear that the least motion of the driving-screw will, in the most
gradual and micrometrical manner, upset this balance of colour, by diminishing
the power of A more than B, and of B more than c, and by continuing the
motion, this change in the proportion of the three colours composing the depolarized
beam will proceed in the same direction, and in the same ratio, until one of the
neutral axes is reached, in which position a becomes at once inoperative. On again
driving the selenites, A begins to-increase in intensity whilst B is diminishing ;
and soon another neutral axis being reached, B, in its turn, becomes inoperative,
and then having passed the neutral position, proceeds onwards, with gradually
augmenting power, to reinforce A, and soon. It will be seen therefore that the
rotation of the selenites, as here effected, corresponds in the fullest sense to gradual
reduction in thickness; and I may compare the depolarizing effect so produced to
that of passing beneath the object a wedge of selenite, of micrometrically small
angle and of infinite length; and the chromatic results to those obtained by an.
artist, who, having the primary colours, A, B, and c on his palette, has the power

of combining them in all proportions, and skilfully mingles them according to his
wants,

"Journal, Nov. 1, 1969. NOTES AND MEMORANDA. 279

ment will prove by no means to be limited to the single object viewed,
but also to embrace somewhere within the limits of a half rotation of the
lower prism (the selenites themselves now remaining stationary) the
finest optical development of many other slides containing tissues of
the same or closely allied character. For example, I found a mag-
nificent setting for exhibiting the cuticle of the Equisetum; and I
have no vegetable cuticle in my possession that does not come out
superbly under the same selenite adjustment, but with a different posi-
tion of the polarizer. So in relation to deep-coloured entomological
objects difficult to polarize, and many others, they class themselves
under certain optical heads as to the seitings, only needing a changed
position of the polarizer; and thus a great amount of time and
Jabour is saved, for the prism can be set to its recorded reading in-
stanily, whilst the instrument remains in situ—in fact, without any dis-
turbance of the general arrangements at all. Lastly, by means of this
polariscope the elementary colours can be mingled in any order or
proportion that may be desired; so that any coloured field whatever, of
absolute uniformity throughout, from the dirtiest brown to the deepest
and purest azure blue (even by lamp-light), may be produced instantly
by making a known setting. In conclusion, I wish to point out that
this is essentially an instrument of precision, and therefore demands
skill and patience on the part of the operator to make it do its work ;
but when employed with the ability and tact characterizing all skilled
microscopists, it 1s competent to yield results of surpassing delicacy
and beauty.

This demand upon the operator’s skill and patience, however, is
only that made by every instrument of precision (witness wide-angled
objectives); for the greater the range and powers of any instrument,
the more care and thought must necessarily be employed in its use.

NOTES AND MEMORANDA.

The Montreal Microscopic Club.—This club, which was estab-
lished last year, has already proved itself a success. In plan it is
something like that excellent working body the Dublin Microscopical
Club. The club appoints a secretary, who arranges for the meetings,
and suggests a special subject for illustration at each. The host for
the evening is the President of the club; minutes are recorded and
read, visitors introduced, miscellaneous business discussed, and micro-
Scopic investigation proceeded with. At 10.30 p.m. the President
announces the adjournment, the microscopes are returned to their
cases, and a parting cup of coffee closes the séance. During the
intervals of meeting the Monthly and Quarterly Microscopic Journals
circulate amongst the members, and afford material for discussion and
illustration.

A Translation of Stricker’s Histology.—It is said that the New
Sydenham Society has selected for translation Herr Stricker’s ‘ Hand-
buch der Lehre von den Geweben.’

280 NOTES AND MEMORANDA. Ne

Photographing Diatoms.—The ‘ British Journal of Photography,’
in replying to a correspondent, suggests that he should avoid diffi-
cult subjects; at first it would be much better to try such an object
as Pleurosigma littorale, which contains 24,000 lines to the inch,
than the P. ETD, which contains 85,000, and would require an
objective of +4,th of an inch to show the markings. The former is
within the range of a good 1-inch power, the latter could not be
seen by it.

Polarizing Crystals from Logwood.—At the concluding sessional
meeting of the Literary and Philosophical Society of Manchester,
Mr. Dancer stated that he had received from Mr. Richard Dale, Corn-
brook, some Hematoxylin—the source of the colouring properties of
logwood. From the appearance of the crystals Mr. Dale expected
they would form a polarizing object, and Mr. Dancer found that
opinion to be correct. Mounted slides of the crystals from an alco-
holic solution were exhibited to the meeting by polarized light; they
are quite equal to Salicin in intensity of colour, and do not require
the aid of a selenite stage. They form a welcome addition to the list
of polarizing objects.

Milk of diseased Cows under the Microscope.—In the ‘ Lancet’
of October 23rd, Professor Brown has given an aceount of his ob-
servations on the milk of cows suffering from the “foot and mouth
disease.” He has given numerous illustrations of specimens seen
under high powers, and showing the presence of Bacteria and allied
vegetable forms in abundance. The details will be found in ‘our
summary of “ Progress.”

The Microscope attacked and defended in Paris.—A great battle
has been taking place in the French journals between two well-known
savants. M. Nélaton, surgeon and senator, contended that the micro-
scope is valueless in medicine, and that it often leads to mistaken
diagnosis. But his assertions have not passed unchallenged, for M.
Verneuil has given him a pointed reply in the columns of the ‘Gazette
Hebdomadaire.’ After having stated what great results the micro-
scope has afforded in the hands of such men as Robin, Broca, Lebert,
Davaine, Virchow, Kolliker, and others, and after having mentioned
that it had now become the indispensable complement of anatomical
research in the dead-room, throwing a brilliant light on the origin,
the evolution, and the transformation of those innumerable lesions
which destroy man, M. Verneuil asked M.Nélaton whether he be-
lieves that all surgical science may be acquired in the ward of an
hospital. If not, and if, on the contrary, he (M. Nélaton) admits the
assistance of the accessory sciences, if he makes use of chemical
agents and of physical instruments, if he practises vivisections, if he
utilizes statistics, if he consults J. L. Petit, Scarpa, Langen, and
Syme, why should he disdain the microscope? “ For if it is good to
diagnosticate stone by the aid of a sound, polypi with the laryngo-
scope, an amaurosis with the ophthalmoscope, paralysis by means of an
electric machine, diabetes with potash, why reject the lens for recog-
nizing leucocythemia or spermatorrhcea ? ”

Monthly Mi ical ‘
Journal, Nov. 1, 1869. ( 281 )

PROCEEDINGS OF SOCIETIES.*

Royvat Microscopical Society.
Krnq’s CoLirce, October 13, 1869.

The Rev. J. B. Reade, F.R.S., President, in the chair.

The minutes of the last meeting (June 9th) were read and con-
firmed.

A list of donations was read, and the thanks of the meeting pre-
sented to the respective donors; a special vote being accorded to
Mr. Ross, who, as the President announced, had given to the Society
new immersion front lenses for the 1th and ;4;th object-glasses which
he had already presented to the Society.

The President said that it had been intended that a paper by Dr.
Pigott, of Halifax and London, “On High-power Definition, with
Illustrative Examples,” should have been read ; but it would be de-
ferred until the next meeting, when he hoped Dr. Pigott would be in
London, and able to read his communication personally. The Presi-
dent explained that the paper contained an account of an examination
of the Podura scale, which gave results quite different from those
which were usually obtained, the whole surface of the scale being
resolved by Dr. Pigott into minute beads ; and the President handed
round a drawing made by Dr. Pigott in which the “note of exclama-
tion ” marking generally seen by observers appeared as a number of
bead-like bodies. The President, while reserving his own doubts as
to the accuracy of Dr. Pigott’s views, hoped that before the next
meeting the Fellows would examine the object for themselves, and
come prepared to discuss it. The President also announced that Mr.
McIntyre would read at the meeting in November, a paper on a
related subject, viz. “The Scales of Certain Insects of the Order
Thysanura.” |

Mr. Slack observed that it might assist Fellows who wished to take
part in the discussion that would be raised by Dr. Pigott’s paper if
they examined a good test Podura scale with a high power and uni-
lateral light obtained by Reade’s prism, or by a single radial slot-stop
in an achromatic condenser. With Beck’s .},th he could easily show
a dotted structure ; but several appearances obtained by varying the
incidence of the light, and by infinitesimal changes of focus, seemed
equally entitled to consideration, and were very difficult to interpret.

Mr. Hogg exhibited a phial containing a quantity of dichroic fluid
which had been found by Mr. Allbon in a ditch not far from town.
The fluid obtained by Mr. Sheppard, of Canterbury, who first dis-
covered and described it, contained a great deal of animal life, while
that exhibited by Mr. Hogg was almost entirely composed of a con-

* Secretaries of Societies will greatly oblige us by writing out their reports
legibly—especially the technical terms—and by “underlining” words, such as
specific names, which must be printed in italics. They will thus ensure accuracy
and enhance the value of their proceedings.—Ep. M. M. J.

t We learn from Mr. Reeves, Assistant-Sec. R. M. S., that Mr. Allbon’s fluid

came from a ditch between Mortlake and Kew, and contained Batrachospermum
atrum in a decomposed state.

282 PROCEEDINGS OF SOCIETIES. — [*youthly, Microscopical
fervoid growth, the sides of which were cove-ed with cells filled with
pseudo-navicule. When examined by transmitted light the fluid gave
a delicate bluish pink colour, and by reflected light a reddish hue.
Under the micro-spectroscope, its spectrum is just that described by
Mr. Browning in vol. vii., 1867, of the Society’s ‘ Transactions. A
few pieces of camphor serve to preserve the fluid ; and although the
specimen exhibited had been corked up for several ‘months, the colour
is nearly as good as when it was fresh gathered, and the spectrum
reaction quite perfect.

The President then requested Mr. Carruthers to read a paper on
the ‘“ Plants of the Coal-measures.”

Mr. Slack wished to call the attention of Fellows conversant with
crystallography to the curious instance mentioned by Mr. Carruthers,
in which, after the charring of the vegetable structure, although the
particles of carbon preserved the exact form of the vegetable cells,
they had opposed no obstacle to the crystallization of the carbonate
of lime, which had gone on through their interstices as though no
obstacles had intervened.

Mr. C. Brooke stated that structure is much interfered with by
foreign matter—the sandstone of Fontainebleau, for instance, assumes
the form of rhombohedral crystals of calcite. The stone does not
contain more than 5 to 7 per cent. of carbonate of lime; but the 95 per
cent. of silex seems to be dragged into form by the 5 per cent. of car- -
bonate of lime which controlled the character of the crystallization.

Dr. Murie alluded to the preservation of the form of straw after
carbonization in a furnace.

Mr. Browning suggested, as an important line of research, that
certain organic fluids should be mixed with solutions of orystallizable
substances, in order that it might be seen in what cases the organic
matter would be enclosed in the crystals formed by evaporation.

Dr. Lawson hoped that the Fellows would employ a little of the
time hitherto devoted to the study of Diatoms, &c., to the interesting
questions brought forward by Mr. Carruthers. With reference to the
remarkable combination of types mentioned by Mr. Carruthers, he
would ask whether he considered these cases as corroborative of the
Darwinian doctrines ?

The President said it was satisfactory to note the important ser-
vice rendered by the microscope in Mr. Carruthers’ investigations.
He thought Dr. Murie’s remarks not exactly parallel to the instances
adduced by Mr. Carruthers. Dr. Murie showed that the process of
carbonization did not interfere with the form of the original structure
of the solid material of plants; but this was not the point taken up
by Mr. Carruthers, who showed that the process of crystallization was
not interfered with by the presence of foreign matter. He (the Pre-
sident) had tried several experiments with cereal plants, which he
burnt in a platinum spoon, and found that by taking a small portion
of the siliceous residue, which he could just see with the naked eye,
and placing it under a ith glass, that the beautiful conformation of the
solid structure of the plant was distinctly seen. The President then pro-
posed a vote of thanks to Mr. Carruthers for his interesting address.

Mr. Carruthers in expressing his acknowledgments for the manner

ao er oees, | + PROCEEDINGS OF SOCIETIES. 2838

in which his address had been listened to, declined entering upon the
Darwinian controversy.

Mr. Hogg then read a paper, by Brevet Lieut.-Colonel Woodward,
Assistant Surgeon of the United States army, on “ Immersion Objec-
tives and Nobert’s Test-plate,” which will appear in the next number
of the Journal.

Mr. Hogg said he thought that the paper prints of Nobert’s test-
lines were better than the glass positives received with the paper and
exhibited to the meeting; that in his opinion the photographs taken
with Powell and Lealand’s th last year by Dr. Woodward were far
more perfect, the lines being more sharply defined. The wavy indis-
tinctness which Dr. Woodward in his former paper said represented
spurious lines could be seen in all the bands; on close inspection of
the two photographic paper prints, which were said to show spurious
lines in the 12th, 13th, 14th, 17th, and 18th, it was difficult to say
whether there is any difference between them and that said to resolve
the 18th and 19th bands into true lines. He had observed a fine series
of lines barely separated from the rest by a dark broader line in most
of the bands, which were doubtless due to diffraction ; but another set
of very fine lines on one side of the 19th band looked more like true _
lines than those believed to be so. These lines also increase the dif-
ficulty of counting accurately, and consequently he had not been able
to satisfy himself in a single count. He (Mr. Hogg) would like to ask
Messrs. Powell and Lealand whether the immersion lens used by Dr.
Woodward can be used either as a wet or dry objective; and what
is the increase of the magnifying power of their ;4,th when converted
into an immersion lens? In Mr. Hoge’s opinion immersion objectives
were a great gain to microscopists.

Mr. Browning said that diffraction spectra would almost certainly
be produced by Nobert’s lines acting as a grating. The lines seen on
each side of the bands had probably this origin. If spectra over-
lapped each other, a certain number of the lines would probably be
lost. He did not think the limits beyond which no lines could be
resolved could be determined theoretically. It must be decided by
experiment, and the investigation had to be carried on under great
difficulties. He suggested thallium as the best source of a pure mono-
chromatic light.

Mr. Brooke thought that the bands brought out on the photo-
graphs referred to by Mr. Hogg, were much more clearly marked
than on the glass slides, for on both sides of the latter spectral lines
would be observed. Again, on one side of the plate six lines would
appear in a band, on the other side fourteen could be seen. These
appearances were probably due to the oblique direction of the light.

Mr. Lobb doubted whether the lines on Nobert’s test-plate could
be clearly defined beyond the 16th band by any glass whatever; but
Messrs. Powell and Lealand had constructed a test-object ruled at the
rate of 100 lines to the ,)55th ofan inch. These were clearly defined
by their ;',th and ;!,th immersion lenses. The podura scales were beau-
tifully defined by the same objectives, and so were the lines on the acus.

284 PROCEEDINGS, OF SOCIETIES. [Monthly Microscopteal
dry objective was about 800, and as a wet objective the power was
increased by about + , making the magnifying power about 1000.

Mr. Mayall defended the paper which he had written on the
subject of Nobert’s test-lines, having taken Dr. Woodward’s paper as
it was printed. He thought that Dr. Woodward, when he wrote his
former paper, had not carefully studied the immersion system. In
his previous paper, he (Dr. Mioodward) spoke of not finding the th
of Hartnack go as far as the 34th dry lens of Powell and Lealand.
In the present paper he said that the ;},th of Hartnack did more than
Powell and Lealand’s jth or th; that is, he could define as far as
the 15th band. He (Mx. “Mayall) had said that he could not count the
lines beyond the 12th band, and he still maintained that in a photo-
graph no band beyond the 12th could be counted ; the uncertain
number of spectral lines rendered this very difficult.

A vote of thanks was then passed to Dr. Woodward for his com-
munication.

The meeting was then adjourned until the 10th of November.

Donations to the Library and Cabinet from June to Oct., 1869:—

From

Land and Water. Weekly oe fe wale 1) Salk p netgear ea an
Scientific Opinion. “Weekly... 2.0. se {de ee
Society of Arts Journal. Weekly .. .. .. . “su. eugene
The Student. 3 Parts. “in or | oe) oe, Site ioe, SAU os lararas
Popular Science Review, Nos. 323 wk le te Publisher,
Transactions of Linnean. Society, Part ome oe we ele) eae aaaO Rena
Smithsonian Report for 1867... Institution.
Natural History Transactions of Northumberland and Dur- ;

ham, Vol. III., Part 1 ag ees as on» MOCIELE.
Journal of Quekett Club. 2 Par tg ee ale. ot el ao, uae ale
‘Reade’s Prism.” . By 8. Highley 2. 45 1. Sun Jia eae
Canadian Journal. ;
Quarterly Journal of Geological Society . <0 la! WS @gnente
Journal of Linnean Society. 3 Parts, and Vol. XI... “» SAoClety:
Retia Mirabilia Circumvertibralia. By Dr. J. Schébl .. .. Author.
Report on Excisions of the Head of the Femur for Gunshot

Injury. By Lieut.-Col. G. A. Otis, U.S. Army .. .. Surgeon. Gen, U. 8.
Sulla Produzione di Alcuni Organismi Inferiori esperienze.

Professori G. B. Crivelli and L. Maggi Authors.
Intorno Alle Cellule del Fermento. Professori G. B. Crivelli ®

and L. Maggi oe » ton 9 AE ORS:
Intorno al Genere AZolosoma del ‘Professor D. L. Magei .. Author,
A Translation and Abridgment of all the Papers relating to

Natural Philosophy read before the Royal Academy of

Sciences at Paris, from 1699 to 1720. By John Martin,

F.R.S., and Ephraim Chambers, F.R.S. .. Dr, Millar.
Description Raisonnée des Organes ‘des Plantes. Par M. A.

P,. De Candolle. 2° Vols... 00 h...0 P20 Nal ga as
Photograph of Microscopic Life. By H. mae mie from a

drawing by H. Richter, Esq. .. H, Davis, Esq.
One dozen Slides of Test-objects sis W. Wright, Esq.
Half-a-dozen Slides of Max Schultze’s Siliceous Vesicles, ‘ilus-

trating Diatom Structure .. Thos. Hennah, Esq.
One dozen Injected Slides, from different ‘Dar ts of Dr, Thudi-

chum’s Trichinous Rabbit . .. Mr. Thos. Norman.
Immersion Fronts to Mr. Ross’s ith and Lth ‘Objectives .. Mr. Thos. Ross.

Water W. REEvEs,
Assist,-Secretary.

ee crosconical PROCEEDINGS OF SOCIETIES. 285

QueKert MicroscopicaL Crius.*

At the ordinary meeting of the club, held at University College,
September 24th, P. Le Neve Foster, Esq., M.A., President, in the
chair, five new members were elected, and five gentlemen were pro-
posed for membership. A number of donations to the club were also
announced, and the thanks of the meeting returned to the donors, The
Secretary read a paper by the late Dr. J. J. Wright upon the “ Har-
vest Bug” (Zrombidium Autumnale), and which was illustrated by
microscopic preparations. 'The paper described the appearance of the
insects, their habitat, and habits as far as known, and considered that
they were the young or immature form of some species of Tick. It
was a common belief that the great irritation caused by the bite of
these insects was occasioned by their burrowing under the skin; this,
however, was believed to be erroneous, as no orifice could be disco-
vered in the wales produced, nor was the insect provided with means
for making an incision sufficiently large for the purpose. The wales
closely resembled those produced by the stinging-nettle, in which also
examination fails to detect any puncture; the inflammation in both
cases being doubtless due to the injection of acrid fluid. Dr. Braith-
waite thought that Lectis would be a more proper designation than
Trombidium for these insects, the latter being that of the common red
Earth Mite. He did not think that the fact of its having only six
legs necessitated its being a larval form. Mr. M. C. Cooke said that
although no further development was at present known, it was gene-
rally considered by entomologists that this was a larval form of some
species of Arachnida, and that it belonged to the section Trombidide,
in which the larval form was hexapod. A species was known as com-
monly parasitic upon Tipule and Dragon Flies; this had six legs,
and was the larval form of an insect which in its perfect condition was
purely aquatic. He entirely differed from the opinion that the Har-
vest Bug was a larval form of Tick; for although in this state the
Ticks were hexapod, yet they so closely resembled the perfect and
octopod insect thag there could be no doubt on this point. Mr. Arnold
remarked the circumstance that the Harvest Bugs commonly bit per-
sons under ligaments, or wherever there was a pressure from any
article of dress. Mr. McIntire suggested that it would be an easy
matter to settle the question of the identity of this insect with the
young of the Earth Mite, which was very abundant, laying eggs in
March, which were hatched in June.

Mr. Wight read a short paper “On the Use of Reade’s Prism as
a Polariscope,” the mode of application being exhibited in the room,
The Secretary introduced to the notice of the club a new form of
microscope for aquarium observation, the invention of Mr. J. W.
Stevenson. The instrument consisted of a bar of brass fitted with
clamps for firmly fixing across the top of a tank; on this the mount-
ing of the microscope tube was so arranged as to slide from end to
end as required, and by means of two jointed motions could be directed
to any portion of the tank, the adjustments for depth and focus being

* Report supplied by Mr. R. T. Lewis.

286 PROCEEDINGS OF SOCIETIES. [ry ee eo
accomplished by a slide. A glass tube, closed at the lower extremity
by a piece of thin covering-glass, was attached to the mounting, and
the tube of the microscope being placed inside this, the instrument
could be efficiently used without any portion of it coming into con-
tact with the water. It was announced that a class for the study of
Biology would be commenced in October by Dr. Braithwaite; and Mr.
Suffolk intimated his willingness to repeat his course of lectures upon
Microscopical Manipulation. The proceedings terminated with a con-
versazione, at which many objects of interest were exhibited, amongst
which some very beautifully executed coloured drawings of magnified
insects by Mr. Richter deservedly attracted much attention.

Ontp CHANGE Microscopican Socrety.*
September 24th.—The President, Charles J. Leaf, Esq., F.L.S.,

in the chair.

The new session of the Society was inaugurated by a lecture on
*“ Deep-sea Dredgings from the Shores of China and Japan,” by Pro-
fessor T. Rymer Jones, F.R.S., &c.

The lecture was illustrated by several mounted slides prepared by
the Professor, and presented by him to the Society.

The thanks of the Society were unanimously accorded to Professor
Jones for his interesting and instructive lecture, and for his donation
of slides to the cabinet of the Society.

Mr. Piper called the attention of the Society to a new and useful
strainer for collecting-bottles, by which the contents of several can be
condensed into one, the surplus water passing out through wire-gauze.
The apparatus is very portable, and is devised and made by Mr. Maginie,
of 37, Queen Square, Bloomsbury.

Several interesting objects were exhibited at the conversazione
which followed.

October 15th.—Chas. J. Leaf, Esq., F.LS., F.S.A., &., the Presi-
dent, in the chair. There were about sixty members and visitors
present. Mr. J. R. Jackson, A.L.S., Curator of the Botanical Museum,
Kew, delivered a lecture on “How a Plant Grows” which he illus-
trated by numerous sections of wood, prepared specimens of vegetable
structure, and diagrams.

Mr. S. Helm, F.R.MS., the Hon. Sec., read a paper “On what I
saw at Walton-on-the-Naze,” containing remarks upon the structure
and habits of the Actinia, Cydippe pomiformis, Noctiluca miliaris, Lao-
medea geniculata, and the Pycnogonide.

The thanks of the Society were given to Mr. Jackson and Mr.
Helm.

At the conversazione which followed, amongst other objects ex-
hibited, were the new Polype (not yet named), from the Victoria
Docks, by Mr. C. J. Richardson.

Fredicella sultana, by Mr. Helm, who also exhibited a collection of
fossil shells from Walton-on-the-Naze, from the Red Crag, and pre-
sented duplicates of them to the Society.

October 22nd.—The President in the chair. Professor T. Rymer

* Report supplied by Mr. S, Helm.

et Roe ee PROCEEDINGS OF SOCIETIES. 287
Jones commenced a second course of ten lectures on “ Comparative
Anatomy,” beginning this course with the Crustaceans.

The Professor took a lobster as a type of the family, and dissected
it, explaining its various parts.

BrigHton AND Sussex Naturau History Socrery.*

October 14th.—The President, Mr. T. H. Hennah, in the chair.
An evening for the exhibition of specimens, when a variety of orni-
thological, entomological, and botanical specimens, many of them
very rare, were exhibited by various members; but nothing relating
to microscopical science was introduced. It was announced that Mr.
Smith would read a paper at the next meeting “On the Mosses of
Sussex.”

OxtpHAmM Microscopican Socrery.t

On Tuesday evening, October 12th, the quarterly meeting of this
Society was held. There was a good attendance of members and
friends. A paper “On the Microscope in Geology” was read by Mr.
John Butterworth. After referring to the usefulness of the micro-
scope to students generally, Mr. Butterworth proceeded to state that
by its aid the geologist was enabled to trace the various phases of
animal and plant life existing through the different geologic ages,
from the lowest Silurian up to the present, and that the important
discoveries made through its agency have given a great impetus to,
and interest in, the study of fossil remains. Its use in ascertaining
the characteristics of the crystalline, stratified, and fossiliferous varie-
ties of rock, was described at considerable length, and illustrated by
numerous beautifully-prepared specimens. ~

The most interesting part of the paper was that which treated of
the fossiliferous rocks, sections of which, from the Dudley limestone
and from the Yoredale rocks in the Hebden Valley, were exhibited,
showing the internal structure of the corals, zoophytes, goniatites,
sponges, &c., of which they are composed.

Special attention was called to the fact that the coal-fields of Lan-
cashire and Yorkshire are remarkably rich in fossil plants and fish-
remains, and that in no part perhaps were more interesting specimens
to be met with than in and around the town; some of which, gathered
and prepared by various members, including teeth and scales of fishes,
coprolites, and fossil wood, were shown under the microscope, by which
the details of structure were brought out with remarkable distinctness.

Mr. Butterworth fully described the method by which sections
for the microscope may be cut and prepared by the amateur at but
little cost beyond time and patience. At the close of the paper, an
interesting discussion took place on the merits and peculiarities of the
various objects exhibited, which added greatly to the information and
interest of the meeting.

A vote of thanks was unanimously accorded to Mr. Butterworth
for the valuable information communicated.

* Report supplied by Mr. T. W. Wonfor. + Report furnished by Mr. R. Horne.

288 BIBLIOGRAPHY, | SOIMEEL aaeaaene

Brisgrot MicroscorPrcAL Society.

Wednesday, October 20th, 1869.—The first meeting of this Society
for the session was held on this evening, Mr. W. J. Fedden, President,
in the chair. There was a large attendance of members. The formal
business having been transacted, Dr. C. T. Hudson read a paper “On
Black-field, Opaque, and Oblique Illumination, exhibiting some of the
latest contrivances.” 'The effects produced by means of Reade’s Prism
and Wenham’s Truncated Lens were shown, those with the latter
being particularly fine. The author then described a new mode of
dark-field illumination which he had devised, by means of which large
objects—such as entire insects—might be viewed under comparatively
high powers. The effect produced by this method was very beautiful,
and excited the admiration of every one present.

Mr. F. R. Martin brought for exhibition one of Collins’s new dis-
secting microscopes. The general opinion of the meeting seemed to
be that it was an improvement upon most of the forms of dissecting
microscope hitherto constructed.

A vote of thanks to Dr. Hudson terminated the proceedings.

BIBLIOGRAPHY.

Etudes Spectroscopiques sur le Sang; par R. Benoit. Paris.
Bailliére.

Das Menschliche Haar von Dr. E. Pfaff. epee Wigand.

Vegetable Physiology. By Edwin Lankester, M.D., F.R.S.

Beitrige zur Anatomie und Physologie von Hee C. Eckhard.
Giessen. Roth.

Bryotheca Europea. Fasciculus 22, von Dr. L. Rabenhorst.
Dresden. Ebend.

Geschicte und Litteratur der Lichenologie von den altesten Zeiten
bis zum schlusse d. J. 1865, von Herrn A. Krempelshuber. Miinchen.
Kaiser.

Hepatice Europaese, von L. Rabenhorst und Dr. Gottsche. Fas.
34-47. Dresden. Hbend.

De quelques Erreurs ou Préjugés en Physiologie végétale ; par
M.C. Bachy. Lille. Danel.

Atlas zur Pathologie der Ziéhne von M. Heider und C. Wedl.
Leipzig. Felix.

Beitrage zur Kenntniss der Bryozoen, erstes Heft von Dr. H. Nitschee
Leipzig. Engelmann.

La Chambre noire et le Microscope: Photo-micrométrie pratique ;
par M. J. Girard. Paris. Savy.

Ueber die Embryonalhiille der Hymenopteren und Lepidopteren-
Embryonen von Herrn M. Ganin. Leipzig. Voss.

i\

o.

5
a

e Monthly Mi

Fl. XXX

ero scopical Journal Dect 1.186

Dcailes ete

S555 FP sogasoy UC

\

nL \

\
SS

aS

ee
SS
Podura

[to illustrate D? Pig ott’s paper)

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SK

aN

SN
SS

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~~

DF Pigott del. Tiffen West se.

THE

MONTHLY MICROSCOPICAL JOURNAL.

DECEMBER 1, 1869.

I.—Further Remarks on the new Nineteen-band Test-plate of
Nobert, and on Immersion Lenses. By J. J. Woopwarp,
Assistant-Surgeon and Brevet Lieutenant-Colonel U.S. Army. .
Contributed by permission of the Surgeon-General.

(Read before the Roya Microscoricat Society, Cctober 18, 1869.)
(Communicated by Jabez Hoee, Hon. Sec.)

Tue ‘Quarterly Journal of Microscopical Science’ for October, 1868,
contains (p. 225) a short article in which I record the results of
certain experiments made by me with the new nineteen-band test-
plate of Nobert. In that paper I stated that I had obtained the
best results with the sth objective of Messrs. Powell and Lealand,
of London. The ;oth of these makers, which in my hands had
excelled their th on Podura and other test-objects, proved inferior
on this plate, apparently because the cover of the object was too
thick to allow the lens to do its best. With the = th I satisfac-
torily resolved the true lines of the fifteenth band of the plate; and
subsequently my friend and assistant, Brevet-Major E. Curtis,
Assistant-Surgeon U.S.A., prepared a series of photographs of the
several bands, showing the true lines in each, from the first to the
fifteenth inclusive. I was, however, unable to make out the true
lines in the last four bands with any lens then in my possession.
I conceived the idea, nevertheless, that if I could procure a test-
plate ruled on a thinner cover, so as to give the z>th full play, I
might go farther. I therefore wrote to Nobert, who, after long
delay, furnished me with a new test-plate, wnicn reached me during
March of the present year. This test-plate cannot be too highly
praised for its delicacy and beauty. The lines are ruled on the
under-surface of a square of thin glass the 345th of an inch thick,
which is cemented to a glass circle the y}oth of aninch thick. This
circle is mounted over a round aperture in a strip of burnished
brass 3 inches by 1, on which is inscribed the usual memoranda
placed by Nobert on his nineteen-band plates.
VOL, IL. xe

290 Transactions of the OTE eee

It will thus be seen that the new plate not only permits the
use of objectives of the shortest focal length known, but that it is
also most favourably constructed for the use of oblique light or of
an achromatic condenser of extremely short focus.

This plate was accompanied by an interesting letter from Nobert,
dated Barth, February 26th, 1869, in which that skilful optician
acknowledges the receipt of the photographs of the several bands,
copies of which I had sent him, and, after speaking of them in a
highly complimentary manner, admits that they exhibit the true lines
up to the fifteenth band inclusive. He goes on to express his belief
that the resolution of the higher bands is a physical impossibility,
an opinion which he bases upon Fraunhofer’s formula with regard
to the spectra produced when light is permitted to fall upon closely-
Xr
b )
the length of the undulations, by b the distance between two lines
of the grating, and by # the angle of the refracted rays, gives for
sin @ an impossible value when 6 becomes less than 2X.” Nobert
further refers to his paper on gratings in Poggendorff’s ‘ Annalen ’
for January, 1852, which those interested in the mathematical
aspects of this question will find worthy of examination.

If the view taken by Nobert of the significance of Fraunhofer’s
formula is correct, the shortest wave-length in the visible part of
the solar spectrum would appear to be the measure of the smallest
dimension we can ever hope to render visible by means of the micro-
scope; and it becomes, therefore, a matter of great interest to know
whether he has rightly applied the formula, and whether it can be
shown by actual experiment that the limit he imagines has any real
existence. Nobert himself would appear to have entertained some
little uncertainty as to his own deductions, for he writes :—“ I am
therefore very anxious to learn whether in resolving the lines of
the test-plate we shall be able to progress beyond the fifteenth
band. It would be a very important step, and one which would
warrant the hope of the further improvement of the microscope.” _

After reading Nobert’s letter, I sent it to my friend F. A. P.
Barnard, President of Columbia College, well known for his studies
in connection with the application of mathematics to optics, with
the request that he would give me his opinion as to the application
of Fraunhofer’s formula to the question of the visibility of closely-
ruled lines when observed under the microscope. Dr. Barnard
replied in a letter, dated April 3rd, from which I make the fol-

lowing extract :—

ruled parallel lines. ‘‘ The formula sin « = —, if by \ we designate

“You will find a simple statement of all that Fraunhofer ever
discovered on this subject, in my article in the Smithsonian Report
for 1862, pp. 181-183.

Tt ba Royal Microscopical Society. 291

“ Tf parallel rays * from § fall on the grating G, at any inclination,
the eye at EK (perpendicular to the grating) will see a colour pro-
duced by the interference of the rays whose paths as reflected
from the bars to E differ by half an undulation from the colour
complementary. But this colour will not be seen unless the eye is
at EK. For other directions as F and I” the interference cannot
take place. ,

“The question is not, will these bars be coloured, but will
they be visible. Nobert argues that when there is no colour, the
complement to no colour, z.e. the whole light, must be suppressed.
That is all I have ever been able to make of his argument or
Fraunhofer’s. This is not only theoretically not proved, but ex-
perimentally not true. It would be true both experimentally and
theoretically in light positively monochromatic, provided the eye
received only the perpendicular rays at HZ. But with an objective
that takes in a cone of an angle of from 140° to 175°, it is nonsense
to talk of this question as one settled by theory.

“We shall continue to see closer lines just in proportion as
microscopes and modes of illumination are improved. Probably
there is some physiological difference between individuals. All
these images are faint, and keen eyes will see them better than
dull ones. It would be a good test of the truth of Nobert’s hypo-
thesis to try, if, with a pure monochromatic red or yellow light,
the thirteenth band of the nineteen-band plate is resolvable.

“Qn reviewing the table of wave lengths, and comparing with
Nobert’s statements as to the rulings of the nineteen-band plate,
I am ready to affirm that, if his theory is true, not even the ninth
band can be resolved in monochromatic yellow light.”

At the time I received this letter from President Barnard, I
had already resolved the sixteenth, seventeenth, and eighteenth bands
with a new immersion 7th, constructed for the Museum by Messrs.
Powell and Lealand, of London, and subsequently I succeeded in
resolving the nineteenth band with the same objective. With this
lens a series of photographs of these bands were then prepared by
Dr. Curtis. These accompany this paper, and will be presently
described.

= careful count of the lines in each band gave the following
results :—

15th band .. 46 lines 18th band .. 54 lines
16th .,, ae AO ee (9th «3 eee aimee
ible 2), mes 5)! ears

In obtaining the above results I illuminated the microscope, as
in my former work on the Nobert’s plate, with a pencil of mono-

* Colonel Woodward has sent no drawings for a diagram illustrative of these
remarks, but as the meaning is tolerably plain to students of optics and the remarks
are of import, we do not wish to excise the paragraphs.—Ep, M, M. J.

xo

292 Transactions of the eee

chromatic light obtained by reflecting the direct rays of the sun
from a heliostat upon a mirror, by which they were thrown through
a cell filled with a solution of the ammonia sulphate of copper, upon
the achromatic condenser. Asan achromatic condenser I substituted,
for that belonging to the large Powell and Lealand stand of the
Museum, a 3th of an inch objective of 148° angle of aperture, and
used it without a diaphragm; obliquity of light was obtained by
moving the centering screws of the secondary stage.

I also obtained satisfactory resolution of the nineteenth band,
with the same lens, by using for the illumination violet light,
obtained by throwing the violet end of the solar spectrum produced
by a large prism upon the achromatic condenser used as above,
and subsequently by shifting the prism got successful resolution of
the nineteenth band with blue, green, yellow, orange, and red light.
These results I had the pleasure of exhibiting to Dr. Barnard and
several others.

As for other lenses, carefully tried on the same plate, I obtained
the following results :—

The th of Wales and the 3th and 25th of Powell and Lealand,
all dry lenses, resolved the fifteenth band, but not the sixteenth.

An immersion 7th by Wales resolved the sixteenth band, but
failed to go farther. An immersion 3th by Wales resolved the
seventeenth band, but failed to go farther. A Hartnack immersion
No. “11,” belonging to President Barnard, also resolved the seven-
teenth band, and failed to go farther.

A Tolles’ immersion 1th, just constructed for Dr. J. C. Rives,
of this city, resolved the fourteenth band, but failed to show the
true lines on the fifteenth. This result with the Tolles’ immersion
3th corresponds with the results very recently obtained with a
Tolles’ immersion 4th, just received by my distinguished friend,
Mr. W.S. Sullivant, of Columbus, Ohio, who wrote me May 25th
of the present year :—‘ The immersion lens you inquired about,
which Tolles sent me, was marked ith, but was only a strong 3th
English standard. The utmost it could do was to show true lines
on the fourteenth band.”

These results confirm the opinion expressed in my former
article, that the lines claimed to have been seen, but not counted,
in the nineteenth by a Tolles’ immersion 4th were spurious lines, an
opinion to which still greater weight is. added by the following
result :—A Tolles’ immersion 7th of 175° angle of aperture was
received at the Museum, May 26th, from Mr. Charles Stodder, who
stated in his accompanying letter, that it might be regarded as a
fair sample of Mr. Tolles’ work. With this lens, after numerous
careful trials, I was unable to see the true lines beyond the six-
teenth band.

It will be seen, then, that in my hands the best definition was

et ek es Royal Microscopical Society. 293
obtained by the immersion ,,th of Messrs. Powell and Lealand ;
and I may here say, that on a thorough comparison of this objective
with the dry th and ‘5th of the same makers, I found that not
merely did their new lens resolve higher bands on the Nobert’s
plate than could be made out with the ssth and 35th, but that it
would bear the use of eye-pieces and amplifiers so as to give higher
powers than can be obtained with the oth, with much better
illumination, with better definition, as well as with a practical
working distance. The lens may therefore be especially commended
for anatomical work when the highest powers are desirable.

In conclusion, I desire to remark on two points contained in the
very interesting paper on “Immersion Objectives and Test-objects ”
by Mr. John Mayall, jun.*

Ist. Mr. Mayall says :—‘“ Dr. Woodward seems not to have
been sure of the accuracy of the count he made on his photograph ;
for although in one part of his paper in the current (October)
number of the Journal of this Society, he says the photograph
shows the twelfth band as resolved into thirty-seven lines, farther
on he says that forty is the real number in that band.” This mis-
apprehension on the part of Mr. Mayall arose from a misprint in
the Journal.| On p. 231, fourteenth lie, “12th band” reads
in my original MS. “13th band;” on the thirtieth line of the
same page, I find “12th band” printed instead of “19th band,”
which is the reading of the original. The same article contains
some other singular misprints, most conspicuous among which may
be mentioned, “ Starting’s work on the microscope,” p. 225, instead
of Harting’s; and “Greenhap,” p. 228, instead of Greenleaf. At
the time my article was prepared, I had no doubt whatever of the
true number of lines in all the bands resolved, except the fifteenth,
about which, as I stated, I was uncertain whether the true number
of lines was forty-five or forty-six. At present, additional work
has satisfied me that forty-five is the number, and I am also well
assured of the correct number as given above for the remaining
bands. I freely admit that the difficulty of determining which is
the last real, and which the first spectral line is very great even on
glass positives ; nevertheless, a comparison of several photographs
with each other, and with the bands as seen in the microscope, has
satisfied me that my count is correct.

‘The second pomt in Mr. Mayall’s paper to which I desire to
refer is the following remark :—‘‘ Dr. Woodward’s photographs
support an opinion given by Mr. Wenham many years ago, that
the time would come when photography would reveal minute detail
much more palpably than it can be seen in the microscope.” If by
this Mr. Mayall means that he has not been able to see the lines

* ‘Monthly Microscopical Journal,’ February 1, 1869, p. 90.
+ ‘Quarterly Journal of Microscopical Science,’ October, 1868.

294. Transactions of the Sotto meee

in the Nobert’s plate as distinctly as they are shown in the photo-
graphs submitted, I must presume simply that he has not illuminated
the object with monochromatic light as directed in my paper.
Although certainly it must be admitted that the Nobert’s plate is
one of those objects in which the photograph most nearly approaches
the beauty and detail of the original, and it must be of course
apparent that a photograph will frequently contam details which m
the microscope have escaped the observation of feeble or inattentive
eyes.

In conclusion, I must say a few words about the photographs
taken by Dr. Curtis, copies of which accompany this paper.

The original negatives were taken with the immersion 7th,
without an eye-piece, the distance of the sensitive-plate being such
as to give as nearly as possible a thousand diameters. On these
negatives, or on glass positives printed from them, the count of the
lines may be made under a low magnifying power. Paper prints
taken directly from the original negatives are very unsatisfactory,
the texture of the paper interfering with the printing of such fine
lines. On the other hand, enlarged prints lose so much detail that
the difficulty of distinguishing the last real lime in any band from
the spectral lmes on its margin, is so much increased as to make a
satisfactory count impossible. I therefore send with this paper
two glass positives; the first of which may be used for the study
of the sixteenth, seventeenth, and eighteenth bands, while the
second is especially intended for the nineteenth. I also send three
paper prints enlarged to two thousand diameters, which will serve
to show the general appearance of the lines, but which cannot be
relied upon to guide in the count for the reasons just stated.

Ura Done | Royal Microscopical Society. 295

Il.—On High-power Definition: with illustrative Kxamples. By
G. W. Royston-Picort, M.A., M.D. Cantab., late Fellow of
St. Peter’s College, Cambridge, M.R.C.P., F.R.A.S., F.R.MLS.

(Read before the Royau Microscopican Socrery, November 10, 1869.)
PLATE XXXII.

Iv is well known that the smallest visual angle subtended by a
minute spot capable of being appreciated by the eye varies very
much with the observer, even after proper adjustments have been
made for long or short sight. The writer once tried the following
experiment in order to determine the minimum visual angle.
Receding from a pole, diameter 14 inch, elevated on a rising ground
against the sky, it vanished at a distance of 1150 yards. The pole
was capped with a black ball, to show its locality after the shaft
disappeared. The angle subtended by 14 inch at 1150 yards’
distance is about sta seconds of arc. This occurred in 1834, In
youth the eye is in general more sensitive, but the late celebrated
astronomer, Mr. Dawes, retained surpassing keenness of sight to
the last. To such, “definition” is a comparatively easy task with
lower powers than to general observers. At a distance of a thousand
yards our volunteers are taught that the head of a man sinks between
the shoulders, and an appreciable visual angle is given by the bull’s-
eye at this distance of about 24 min. (2'°29). ‘These facts supply
us with data for judging of the average power of definition.

Now suppose thirty or forty bull’s-eyes in a straight line,
painted black, in contact upon a white wall. Though 2 ft. in dia-
meter, at a distance of a thousand yards only a black lime would
appear; the eye could not, unassisted, in general define the bull’s-
eyes of which it was composed,—or, in other words, definition of a
line of round, black dots, each of about 24 minutes’ visual angle,
would fail. Perhaps if each centre were perforated with an inch
aperture and illuminated from behind, their definition would be pos-

DESCRIPTION OF THE PLATE ON HIGH-POWER DEFINITION.

Fics. 1 and 2.—_Examples of diffraction and interference, producing a very perfect
resemblance of 'Test-scale Podura markings by the intersecting beaded
ribbing of two superimposed azure blue scales.

3 and 4.—Sketch of Podura seen by direct condensed light and of longitu-
dinal beading, with a few beads of the under-surface glimmering
through the upper set.

o to 8.—‘‘ Admiration Test-scale.”’ The general beading shows itself in
a great variety of forms, according to the state of the illuminating
pencils and the focussing upon the upper and under set.

7.—The most perfect resolution hitherto attained by exceedingly patient
and finely-adjusted glasses. The ribbing (6), Fig. 8, is here distinctly
represented by darker beads of the upper rouleaus; the under-set
always appear brighter in colour. Isolated beads, free from collateral
interference rays, assume a natural resplendence and focal point.

8.—a, b, c, d, e, different appearances of the test-scale under different con-
ditions of illumination and vision. The ribbing (6) is preliminary to
the transformation of the spikes of a into the rouleaus of e.

”)

”

?

29

296 Transactions of the se
sible. In the case of double stars visible with Mr. Browning’s

3-inch silvered specula (on favourable nights with 400 diameters),
the closest I believe is Gamma? Andromeda, 745 seconds apart; this
interval with 400 amounts to a visual angle of 400 x 745" = 160",
the smallest perhaps under which the eye can effectively divide and
separate, not merely elongate, fine double stars; and but for the
sparkling glory of these suns, so minute and dwindled in an abyss
of distance, doubtless much closer stars (with instruments more per-
fectly free from aberration) should become visible. Only the finest
known definition can sever those glittering points.

The healthy human eye, then, consisting of an achromatic com-
bination of refracting media, and of a sensitive recipient of rays
whose sensibility is limited to the minuteness of the distribution of
its nerves, differs widely in its powers of definition, and particularly
in its qualification of distinguishing a line from a string of dots
each subtending an angle less than 2’.

Lhe subject of definition is beautifully illustrated by the whole
range of what are termed line test-objects, whether as the various
pleurosigmata, striated scales, or artificial lmes on glass, as Nobert’s ;
the latter, however, being grooves cut or ploughed into glass by a
fine, pointed diamond, cannot offer the same characteristics for defi-
nition as objects whose lines are caused by small, spherical bodies
raised in relief, the complete resolution of which requires besides
definition “ penetration ” (or less angular aperture than is necessary
to catch the shadows arranged lineally upon glass). For these and
other reasons the distinct definition and portraiture upon the retina
of minute illuminated or shaded spherical dots, of small visual angle,
placed in close contact, may be regarded as the severest known
standard test both for the performance of microscopes and telescopes.

The disadvantages of deepening the eye-pieces in place of exalt-
ing the magnifying power of the object-glass or reflector, are at once
so appreciable, in the appearance of haze, cloudy definition, and
obscurity, caused by the increase of the “least circle of confusion,”
and the destruction of aplanatism, that great genius has been
displayed in constructing object-glasses from 7gth to the 5th and
sth of an inch focus, whose performance has almost been regarded
as beyond mere praise, entitling them to the highest honours which
nations in their art exhibitions can confer. Yet in the best glasses
there is a certain residuary aberration (chiefly spherical) which
obscures the clear definition under a power of 1000* of a string of

* To find the visual angle (6) of the 80,000th of an inch under a power of
1000 at 10 inches distance (the usual focal distance of the Last image from the
eye of the observer),

ce a
perpendicular _ 1000 X 89000 dyes
hypothenuse ~ 10 800
Hence 6 the visual angle = 4,8, minutes nearly, or nearly double the visual
angle of a two-foot bull’s-eye seen at 1000 yards target.

Sine 6 =

ty cites | Loyal Microseopical Society. 297

beads less than 80,000 to the inch: whilst a visual angle of 6” would
represent an object whose diameter in the field of a microscope
maenifying 1000 linear must be zzed000th, or less than the
3,000,000th part of an inch. From this we can form some idea
of the exceedingly minute character of objective aberration ; even
for a good 3th object-glass it does not exceed the 50,000th of
an inch.*

The extreme difficulty of defining a minute row of beads arises
from the uncorrected aberrations confusing their images, by which
several images overlap and obliterate the form of individual beads ;
still more is it increased if one set of beads be confused with the
images of an underlying stratum of intersecting rows, forming a
complicated beaded lattice-work, as in many interesting scales.

‘The Society will permit me to observe that I have found in the
difficult enterprise of resolving the Podura scale into its component
beads, the definition may be refined, partly by selecting such pencils
of rays as pass through the lenses of the object-glass, so as to form
an image with the most perfect aplanatism, or freedom from spherical
aberration; all other rays causing haze and nebulous definition,
and therefore with the least possible use of excentrical pencils of
light such as emanate from ordinary condensers. In these high-
power researches the integrity or perfection of the illuminating
pencil of rays is as important as that of the refractions of the ob-
jective. In my experience I have found an oblique centrical pencil
of aplanatic and achromatic cones of light of small aperture (15°
to 20°) of the greatest practical utility, the obliquity being varied
according to the object in view.

Another circumstance is worthy of note, viz. the position of
the stigmatic image, or of the distance from the back lens of the
object-glass where there is a real focus. If a precious stone of
retractive index ~ = 1°6861 can be found, such as is free from a
double image, the equation for aplanatism

: Nee, ares 0

will be satisfied if the gem be a plano-convex lens with the plane
turned towards the object; the image would be formed without
aberration. But till this can be found and worked, a search for the
real focus or best image should not be neglected along the axis of
the instrument.

By elaborate calculation it appears that the variation of the
distance between the front lenses of an object-glass produces a

* The aberration of lenses depends upon their general shape, and for illumi-
nation, crossed lenses should be formed into bull’s-eyes.

Convexo- Crossed lens
Lenses. Piauo-convex. plane. Equi-convex. Crossed lens. reversed.
405 105 150 96 310

Aberration

100000 ’ 100000’ 100000 ’ 100000 ’ 100000 °

9298 Transactions of the [*Sournat, Dee 11800"

change in the aplanatism of the final image viewed by the eye-
piece ; it not merely makes a convenicnt adjustment for the errors
caused by using different thicknesses of covering-glass, which varies
from the +ioth to the +,%;9ths of an inch, but the index on the screw-
collar may be used as a measure of spherical aberration occurring
at the final focal image. The aberration sensibly changes for every
different distance of the final focal image from the object, and con-
sequently with the same object and covering-glass for differently-
constructed eye-pieces. |

The form of the caustic or curve whose successive tangents
represent the aberrating rays passing through the last or back lens
is exceedingly acute, almost approaching a straight line. If F be
the focus for parallel rays passing through the lens L, and inter-
secting the axis at F'; let Sq be the course of an aberrating ray
intersecting the axis at g: and let it touch the caustic curve RPF
at P; let FN = X and PN=/Y. Then the square of PN is pro-
portional to the cube of FN or Y? varies as X*=NX*. And the
aberration consists of two distinct dimensions. The lateral aberra-
tion is, in this case, represented by PN, and the longitudinal by Fq;
it has therefore breadth and length. But lenses may be so com-
bined that for a certain distance of g from L these aberrations can
be reduced almost to nothing.

§ R
Pe

L N 7 F

And it is possible to compensate practically one aberration by
introducing another equal and opposite.

On these principles the investigation of the circumstances requi-
site for enhancing, clearing, or sharpening high-power definition
may possibly be successfully carried out.

For a given distance of the object from the object-glass, the
aberration caused by refraction through a plate of glass of thickness
¢ is doubled or trebled, &c., by making the covering-glass twice or
thrice, &c., as thick: but it also varies in a high ratio as the angle
of aperture of the objective increases. In other words, the con-
fusion of the final image is represented by multiplying the aperture
by the thickness.

To define some of the most minute lines of diatoms fine defi-
nition is often sacrificed to enlarged aperture, which however gives
the additional advantage of increased hight.

It was only by very oblique and most skilful illumination that
black-lined shadows could be obtained in the finest specimens and
also by an aperture large enough to admit such oblique rays, that
the lines could be seen at all: without this aperture, definition was
of no avail with the power employed. Perhaps until a more exqui-

eta Deo oe Royal Microscopical Society. 2.99

site standard for definition ig realized than Nobert’s lines and
“lined diatoms” no great improvement will be made in the best
object-glasses. The writer however ventures to express the opinion
that a new standard for high-power definition will be found in the
minute structure of the Podura scale, which affords the most severe
trial for the correction of residuary aberration with which he is
acquainted. And having given much leisure to the use of this
interesting object in estimating definition and the possibilities of
improvement, he prefers it to all others.

This extraordinary object, dating as a test from the jewel-
microscopes of Pritchard and Dr. Goring to the splendid glasses of
our eminent makers of the present day, has accomplished more
towards the perfection of defining power than any other. It has
done for the microscope what Sir William Herschel’s close double
stars and the rings and satellites of Saturn have done for the develop-
ment of the charming and exquisite revelations of the telescopes of
the time present.

The American Government has lately authorized the exhibition
of photographs of several microscopical objects, taken by means of
Wales’ and Powell and Lealand’s glasses: these sun-pictures,
especially those by Powell’s 3th, s;th, and j>th, agree remarkably
with the accepted appearances beautifully delineated in Dr. Carpenter’s
work and that of Messrs. Smith and Beck.

These photographs, taken by an American artist * and exhibited
in England—might fairly be accepted as a challenge to English
microscopists. But for this circumstance, the writer having awaited
seven years for confirmatory evidence of his own results, now
ventures to bring before the notice of the Society these observations:
and in doing so he begs to remark that he believes they are capable
of two kinds of demonstration, the synthetic and analytic, as far as
the eye is concerned. But in order to obtain similar results, par-
ticular attention must be paid to the following conditions :—

(a.) Illuminating pencil—A cone of light achromatic and
aplanatic ; angle of apex about 20°; inclination of axis
of cone to plane of stage about 20° to 30°. The size of
the condensing lenses employed is of no consequence, the
other conditions remaining the same.

(b.) ‘The scales which are darkest and smallest and with the
longest diameter towards the light should be carefully
chosen first with a good 4-inch at 120 diameters.

(c.) The most patient corrections should be applied as to the
object-glass, chosen distance of the secondary focal image,
and the lenses for the eye-pieces ; and lastly, the foci of
the object-glasses and depth of the eye-pieces (so as to
correct as much as possible the residuary aberration of
the object-glass) should be most carefully selected.

* Colonel Dr. Woodward.

300 Transactions of the ee ee

It is impossible within the limits of this paper to describe further
in detail the arrangements found to be most successful.

Tt is well known that under a low power, as 80 or 100, the
Podura is remarkable for its wavy markings (these are a safe cuide
in selecting the scale), aptly compared to “watered silk.” It is
here that the secret of their cause and nature is to be sought for:
hitherto one which has bafiled the most famous glasses of modern
times. As a simple fact sometimes leads to a suggestion; view
carefully against the light two pieces of the silk woven with the
finest weft and warp placed one over the other: accordingly as one
is lightly stretched more than the other or as the weft of one is
inclined more or less to the weft of the other, instantly an endless
series of waves are developed by the lines of optical interference :
mesh intersecting mesh with infinitely varied effect: but always
waves. Can the waves of the Podura be similarly caused ?

Raising the power to 200 or 250 and using a side light upon
our scale athwart its length, all waviness disappears, and in its
place is seen a longitudinal rzbbing, shaded very darkly; with a
less oblique side light, lucid rhomboid chequers glitter brightly :
the rhomboidal sides, crossing at acute angles, may be seen with a
low power of 500. With 1200 these ribs have divided themselves
into a string of longitudinal beads. But with 2300 they appear to
lie in the same plane, and terminate abruptly on the basic mem-
brane: upon focussing for the strings of beads attached to the lower
side the beading appears in the intercostal spaces. The upper
beads are best seen either green upon a pink ground or pink upon a
greenish ground, which phenomena may possibly arise from the
different dispersive powers or refraction of the various structures or
the correction of the glasses; or even more recondite causes.

When the light is much more oblique, yet achromatic, the beads
appear shaded as roughly represented in the diagram, the inter-
vening spaces showing fine traces of intersecting lines.

Using now an adjusting 34-inch at 250, and rotating the scales,
some of the most favourable positions, with oblique light, inclined
about 15 degrees to the axis of the scale, show a double set of lon-
gitudinal lines forming a lattice-work. These lines are the markings
existing on the other side of the scale.

With 300 to 500 the celebrated “spines” appear, according to
the size of the scale, as very dark short tapering marks (like
“notes of admiration” without the dots!!!). To see these clearly
with 2500 has been considered the ne plus ultra of microscopical
triumphs, and it is consequently with no little diffidence that the
writer ventures to traverse the belief of twenty-five years. ‘The
object of this paper is to show that definition can be further im-
proved under the use of high powers, and if he should succeed in
accomplishing this, the leisure of some years will not have been

eee Royal Microscopical Society. 301

spent in vain. It may be here observed that the adjustment of the
correcting screw of the object-glass plays an important part in
refining the definition, independently of the thickness of the
covering-glass. I may observe that the first sa illustrations
accompanying this paper were effected by the anastatic process
from drawings made direct from the microscope, in 1863, by a
talented lady who is an excellent amateur painter, and who had no
previous knowledge of the subject, and therefore wholly unbiassed.

Fig. 3. Is a rough sketch of the Podura spines illuminated by
direct gondensed light.

Fig. 4. Podura spines resolved into longitudinal strie of beads
with the lower striz: on the under-side of the scale partly visible.

Fig. 5, A rather exaggerated drawing illustrative of the size of
the beads, but correctly giving the appearances of interlacing
lattice-work formed by the upper and under ribs of beading crossing
each other.

Fig. 6. Shows the careful resolution into beading by using a
long-drawn tube: on the left the waviness of the beading is re-
markable; next are seen rows crossing at an acute angle, and on
the right side a more regular display of beading running in straight
lines.

Distrusting at this time (1863) this novel appearance, I re-
peated experiments hundreds of times on different scales, and
sought earnestly for some synthetic proofs, which were finally
found in the appearances (drawn by the same lady) caused by the
intersections of the ribs of the finest and most transparent scales of
“azure blue” in Fig. 1, and a coarser intersection shown at Fig. 2.
The beads to be seen brightly and clearly in the fine scales of
Fig. 1 require very careful adjustments, and the spurious spines
there shown, counterfeit, in every particular, the behaviour of the
spines (which I shall also venture to call spurious) of the Podura
scale.

When the light is almost direct, that is, the axis of the illu-
minating cone of rays is nearly perpendicular to the plane of the
stage, the beads sometimes exhibit black dots, crescentic shadows,
and brilliant points of light, according to the action of the trans-
mitted rays upon their spherical surfaces. Similar dots may be
seen upon the beads of the Pleurosigmata. Had we no visual
direct proof of their sphericity, the symmetrical shifting of the
crescentic shadows according to the direction of the light would
prove their shape.

I may remark that the higher the power can be raised by
lengthening the tube and deepening the eye-piecs, consistently with
a fine definition, the better chance will be afforded for distinguishing
the upper and lower sets of beads crossing each other at an acute
angle upon the upper and lower surface of the intervening basic

302 Transactions of the wsournal, Dee ace
membrane; whilst on the other hand deepening the objective to
gain power limits the focal depth or penetration; the amount of
this depth even of a ith being exceedingly small.

By estimation comparing these beads with those of the P.
formosum of sotoo Inch in diameter, the observed Podura beads
may be reckoned at sodcoth to tsc'oooth of an inch in diameter.
The “spines” usually drawn really embrace in general three or
four beads, whilst the intervening spaces abound with beads seen
through the basic membrane, and very difficult of observation
without special management. :

750 diameters will show with fine definition and a long-drawn
tube and good penetration, beaded strize upon both sides of the
scale when coarsely marked.

1800 with a tth and nearly direct light (which should be
formed as free from colour and astigmatism as possible) will show
in favourable cases chains of beads lying upon the upper surface.

I cannot here too strongly call attention to the beautiful pheno-
menon, which I have always endeavoured to obtain as a fine and
reliable test of approaching aplanatism and heralding a fine defini-
tion, In examining striated bodies—longitudinal bands glisten
with a ruby tint upon a green or yellowish green ground. The
bands appear like pellucid semi-transparent cylindrical ribs, and the
flashing of these bodies with a ruby glow is a signal in my expe-
rience that the aberration approaches its minimum; when the
beading dispels the mist and haze always accompanying the spurious
“ spines.”

With a power of 2500 the beading may be seen to terminate
abruptly, and commence abruptly near the edge of the scale.

The most difficult definition is that of the substratum of beads
glimmering through the membrane nearest the light; on the other
side they are generally of a very bright yellow-green colour, con-
trasting prettily with the deep ruby. colour of the upper beads.

Availmg myself of the aplanatic test above described, and focus-
sing carefully the upper surface of the following tests, I have had
the rare pleasure of seeing the manner in which the structures of
several beautiful objects are arranged.

A. Battledore scales of azure blue.
The whole surface is beaded over: the large beads seen
with a 43-inch are formed of a mass of strings of beads
crossing and recrossing.

B. Fine transparent and smallest striated scales of azure blue.
The upper. ribs appear as distinct ruby-coloured beading ;
between and beneath which are seen partly obsewred
longitudinal rows parallel to and immediately behind the
upper set.

Monthly Microscopical

es Dee 1 ees. Royal Microscopical Society. 303

C. The translucent ribbing of Lepisma Saccharina is formed
of regular beads, and beneath these and radiating from
the quill are lines of smaller beading crossing the upper
set in straight lines, I see these yellow-green, whilst
the upper set are brownish red.

D. By gas-light I observed rows of red spherical beads, placed
upon the surface of the test-object, marked by the pre-
parer of the scale S. Hippocanvpus,* alternating with
yellow-green rows, somewhat encroached upon by the

# upper sets; all running parallel to the axis of the scale.
4000 diameters.

i. The surface of metals and alloys, with a power of 1000
diameters, shows, under reflected light, particles appa-
rently spherical, agglomerated together, with dark lines
separating the particles.

N.B.—Diffraction-rings similar to those observed about minute
stars are abundant for single particles (scattered on paper by gild-
ing) in proportion as the spherical aberration is less perfectly
corrected, but which disappear when the aplanatism is established.

Query.—Are the diffraction-rings of stars due to the undulatory
theory of light, or to the residuary uncorrected aberration of tele-
scopic object-glasses ?

Note.—The perfect definition of a broken surface of metal is a
more severe test of aplanatism than artificial globules of mercury.

I may now, perhaps, be permitted to present to the Royal
Microscopical Society synthetic evidence of the structure of the
Podura, which appears to me to satisfactorily account for the pecu-
har, and I may say, embarrassing phenomena attending the study
of the minute structure of this precious scale.

I beg particularly to call attention to Figs. 1 and 2. A careful
search with a power of 150 among the scales of Polyommatus Argus,
or Azure Blue, always found among the Battledore scales, of which,
indeed, there are several kinds, will be rewarded with appearances
which present the characteristic waviness or watered-silk appearance
so peculiar to the Podura scale under low powers. These draw-
ings, made in 1863, elucidate the cause of the Podura markings.
With high powers, as 1000 to 2000, these scales show similar
beading, and we have here a perfect example of a spurious spine
being formed by lines of interference and diffraction; the beading
being obliterated in the blank spaces, and dark markings or spines
presented, precisely as is the case in the celebrated Podura scales.
To my own mind this synthetic formation of the Podura markings
is perfectly satisfactory and conclusive.

* This diatom is a specimen of Pleurosigma Strigosum.

304 Transactions of the TORE eee

I wish to add here that Mr. Browning pointed out to me that
the beading of the Podura was rather unequal, some of the beads
being larger than others. This is exceptionally the case; but I
have found in numerous observations a great regularity in the size
of the beads on the same scale.

They are most perfectly seen when the axis of the cone of light
coincides with that of the objective, and the cone of light from the
radiant is of very small aperture.

Extract from a Letter to the President.

October 1.—I feel firmly convinced that within afew months
the Podura beadings, such as I have described them, will be
thoroughly established. I purposely delayed publishing my
results in 1862, hoping that further advances might be made in
improving definition, and this has unquestionably been done by the
ammersion lens, which I have used this year with a Powell and
Lealand’s ~.th. With this lens I have been able to confirm the
observations of former years in scales and objects of extreme diffi-
culty. Before using this lens, I had succeeded in gaining a new
intensity of definition in the dry way, and in balancing the uncom-
pensated residuary aberrations; and I have used the Podura scale
as a very exquisite test of the lenticular corrections, though there
are other tests of a higher order still.

I have endeavoured also to improve the definition of the immer-
sion lens by extraneous compensation. |

Beck gives a very beautiful steel engraving of the test-scale
under 1200 diameters. ‘The spines are precise, and exhibited, as
he saw them, and as thousands still see them, and as Colonel Wood-
ward photographs them actinically with Powell and Lealand’s 35th
and s5th. But very curiously, in the middle of Beck’s work, there
is an engraving of the Podura, described “out of focus,” being a
series of parallel bands, which Mr. Aldous has drawn for me with
the camera lucida under 4000 and 2500 diameters. These bands,
as I see them, are wholly composed of beads of the diameter of the
band, the under-beads being out of sight.

The extraordinary difference between the performance of the
Hydro-objective and of the Pneumo-objective (the plate of air or water
making enormous differences in the aberrations of the glasses) must
make it apparent to ordinary common sense that our old-fashioned
glasses are wrong somewhere, and if not in failing to converge the
image of a point to another point, I know not where to find it, 2.e.
in aberration,—chromatic¢ aberration being more easily compensated.
I know it is very difficult to throw aside the creed and belief of
forty years, and I have hesitated a long time to bring forward my
views, being perfectly convinced that there would be a battle of

Monthly Microscopical

Giant, Dec. 1, 1909, Royal Microscopical Society. - 305

the glasses to be fought, and the manner in which the subject of
aberration has been treated amply justifies my apprehensions.

I point to the immersion lens as an irrefragible proof of the
deficiencies of the corrections of old-fashioned glasses to grapple
with some of the exquisite difficulties of microscopic research, and if
my poor efforts shall in any way advance the excellence of defining
power, especially in the higher range of investigations, I shall
in the end feel amply rewarded. The work has been earnest and
sincere.

Norr.—Dr. Pigott desires to have it stated that this paper was sent to the
Royal Microscopical Society on the 21st of May last.—Ep. M. M. J.

VOL. It. xX

306 - The Development of Organisms [Monthly Microscopical

III.—The Development of Organisms in Organic Infusions.
By C. Stanmanp Wake, F.A.8.L.

Havina made various experiments on the connection between
animal and vegetable organisms in their lowest phases, a brief state-
ment of them, and of the conclusions to which they lead, may not be
without interest. A piece of a wine-bottle cork having been put
into a small glass stoppered bottle of distilled water, two or three
days afterwards, on examining the water under the microscope, 1
found that very fine filaments had been produced from some of the
cork cells. ‘There was no appearance of articulation in the filaments
themselves, they having rounded bulging ends, by exudation from
which the growth of the filaments was evidently produced. On the
next examination I found that these had increased in size and
length, and had become branched, and an approach was evidently
being made to the cell formation. Numerous small round bodies
were floating in the fluid, either separately or in masses, and there
was the appearance of similar ones, either in the cells, visible
through the transparent walls, or protruding from them. Some
days afterwards, however, I observed on several of the stems clusters -
of these round bodies, resembling bunches of grapes, and at a
later date some of them appeared to have become elongated and
like bacteria, moved freely and irregularly, though slowly, with a
jerking motion. Moreover, the cells of the fibre had become
further marked, and many of them contained, or had attached to
them, oval pieces of jelly-like substance. -These became separated,
and occasionally united in masses or chains, some of them afterwards
becoming enlarged and more irregular in shape. Another curious
development showed itself in a large mass of very fine filaments
bearing small bodies, oval in shape, but somewhat elongated at one
end. These were apparently infusorial germs, as they much re-
sembled others developed at a later period which were clearly of this
character. They were also, probably, similar to monad-like bodies
which appeared to be contained in many of the cells of the fungoid
growth. These “monads” gradually became active, and finally
they developed into infusoria, like what I believe is an early phase
of Kolpoda cucullus, many of them remaining for a considerable
period attached by fine filaments. At the present moment the
cork infusion displays all these various phenomena, animalcular
life being very abundant, and there is the appearance of a new
phase of vitality in the form of minute seed-like bodies, occasionally
clustered together in large masses. I may mention that this cork
fungus has much the appearance of the so-called “cholera fungus.”
The closest analogy, however, to these phenomena is to be met
with in milk or cream. The changes observable in an infusion

"Journal, Dec. 1, 1569. an Organic Infusions. 307

of this kind I have described elsewhere in the following words :—
“On examining a drop of diluted cream under the microscope, we
find that its globules are of various sizes, and that the smaller ones
have an extremely active movement. Moreover, if a small quantity
of cream be placed in water, after a few hours these smaller glo-
bules are found to have become both more active and more nume-
rous. In the course of some days a further change takes place,
many of them having taken an elongated form, and finally the
cream infusion is full of animal life of a very active character.’ It
is at a later stage that the vegetation makes its appearance in a
form exactly resembling, as I have already said, the fungus de-
veloped in an infusion of cork. There is the same formation of
cells, and the apparent “budding out” from them of masses of
matter resembling jelly. In another infusion these curious-looking
bodies were apparently produced by elongation of the globules them-
selves, and they then amalgamated to form the fungoid stem. All
the globules in this infusion, moreover, “sprouted,” and thus gave
rise to a fungoid growth. In the cream infusion also there is pro-
duced a kind of fruit on the fungus—spherical bodies resembling
the original “ oil-globules ”—and infusorial forms similar to those
met with in the cork infusion are finally produced. This fungus
appears to be a species of Ascophora.

These are the phenomena to be accounted for, and to simplify
the matter I shall first of all state the conclusion I have arrived at
as to the true explanation of them, and afterwards support this
conclusion by other facts which have come under my own observa-
tion. The data are, simply, that, in the one case, from a vegetable
substance—cork—and, in the other, from an animal substance—
milk—both vegetable and animal organisms have been derived in
such a manner as that we must suppose the higher to have sprung
from the lower organism. We are, in fact, in the presence of the
phenomena now explained by an increasing number of men of
science as the result of “ spontaneous generation,” as it is popularly
called, or by virtue of what is scientifically termed heterogeny. I
shall have a few remarks to make on this hypothesis shortly, and
I will say here only that, as usually understood, this hypothesis will
not explain the phenomena in question. Decomposition is abso-
lutely essential to “spontaneous generation,” while here, so far
from there being decomposition, every step in the process is an
evolution of vitality. If we take the infusion of cork, we find that
the fine filaments first developed can be traced distinctly to the cork
cells, and yet these cells remain, apparently, intact, and they may be
seen in the infusion undecomposed to the end of the experiment.
The development is evidently from the cell-contents, whatever these
may be. Moreover, all the further changes which take place pre-
sent themselves simply in the course of this development. The

x 2

308 The Development of Organisms [Mgumnu, Deo tea9.

filaments increase in size and length. Their substance is gradually
formed into cells, from which are thrown off certain bodies, some of
which, with others of analogous character but probably of a dif-
ferent origin, finally and unmistakably take the infusorial form of
life. The whole progress is an evolution of vitality. Hxactly the
same course is pursued in the changes which take place in a cream
infusion, except that the organic so-called “oil-globule” is the
starting-point in the phases of evolution. But if we reject the
hypothesis of “spontaneous generation,” or heterogeny, what other
explanation of the phenomena can be given? It cannot be said
that the germs of the fungoid growth, or of the infusoria, are intro-
duced with the air or the water used in the experiments.* The
phenomena in question completely negative this idea. Nor can we
suppose that the germs of all the products are contained in the
infusion itself. There is, certainly, a starting-point to which all
may be traced—the contents of the cork cell in the one case, and the
cream-globule in the other—but this accounts for the appearance of
the first step only in the series of changes. Driven thus to a
corner, the only conclusion we can draw is that the first germ
is alone necessary. Given the cell-contents or the cream-globule,
all the rest of the phenomena, whether they relate to animal or
vegetable life, must inevitably follow, when the proper conditions of
development are supplied.

In support of this view, I will now detail other experiments I
have made, first, however, referring again to the fungus of the cork
infusion. This we have seen was developed, apparently, not from
the material of the cell walls, but from the cell-contents. Not that
the cell necessarily loses its vitality immediately it becomes what
Professor Beale terms ‘‘ formed material.” In the experiments above
detailed, the cells give forth certain vital products in the course of
the development of the fungus quite independent of the germs from
which the infusorial life is evolved. It may be that these products
themselves again combine immediately to form a vegetable structure,
as I have seen several of them united endwise, and some at least
of the milk-fibres had every appearance of being composed of cells
thus joined and amalgamated. The cell-contents, however, are
clearly the starting-pomt of the phenomena under review, judging
from other phenomena to be now mentioned.

In France, M. Bechamp t has made experiments which establish
“the natural development of bacteria in the protoplasmic parts of
various plants,” and he affirms that this arises from the fact that
the microzyme, or molecular granulations of the plant-tissue, are
the germs of the bacteria. This opinion I have confirmed by the
following experiments :—If a thin section of the tissue of a plant,

* We must dissent from this proposition of the author’s—Ep. M. M. J.
t See ‘ Popular Science Review’ for April, 1869.

Soa eo in Organic Infusions. 309
more especially that of the leaf or flower, be examined under a
microscope, it will be found to contain very numerous small spherical
bodies, having apparently a free movement, these being the mzcro-
zyme referred to by M. Bechamp, and among them bacteria also
may sometimes be seen. Moreover, if a green leaf be moistened
and rubbed on a glass slide, a number of these living molecules—
monads or bacterial germs—are found on the glass when it is
viewed through the microscope. I have seen them come from a
small piece of leaf-tissue in a perfect stream. ‘The cells of the
petal contain great numbers of these bodies, and occasionally here,
as in the leaf-tissue, blotches which appear to consist of masses of
them may be observed. ‘These facts led me to examine the seeds
of certain plants, when I was astonished to find microzyme in
great abundance, more so than in either the petal or the leat-tissue.
In fact, the contents of seeds having a “ fleshy ” perisperm appear
to be made up almost entirely of microzymz, with occasional
bacteria. ‘To see whether these were really what I suspected them
to be, I placed some seeds in water, and after a few days the water
was swarming with most active infusoria of different kinds, in-
cluding that which I have described as a phase of Kolpoda cucullus.
On examining the contents of the seeds themselves the same pheno-
menon presented itself. In one instance the bacteria had a most
curious appearance. A number of them were joined together end
to end, and the united body moved actively through the fluid with
a peculiar undulatory motion.

In a letter in which I communicated some of these facts to
‘Scientific Opinion,’ I stated that the pollen of plants seems “to
consist literally of microzyme cells,’ and that I had found the
organic germs contained in these cells to move freely. This motion
I have repeatedly witnessed, and, on one occasion, several of the
pollen-cells of the common dandelion burst while in the micro-
scopic field, and their contents were discharged and moved freely
through the fluid in the same manner as the microzyme of seeds.
I was much struck with the resemblance between the organic
molecules of the dandelion pollen-cells and those of the nettle,
which I was examining on the same occasion, and I have no
doubt that infusions of them would furnish similar results in either
case. It is difficult to obtain the molecules of the nettle-hair
without the tissue of the hair itself, which renders experiments
with them less satisfactory than those with the contents of pollen-
cells. The phenomena presented by the pollen when placed in
water are most curious, and not the less so because these pheno-
mena somewhat vary in different cases. A few days after placing
some pollen of Scabious in water, I noticed a slight fluffy appear-
ance at the bottom of the bottle. On examining this with the
microscope, it was found to consist of minute filaments of a fungoid

310 The Development of Organisms — [Monthly, Microscoptcal

growth, apparently from some of the pollen-cells. These filaments
closely resembled the fungus of the cork infusion, and the subsequent
evolution was also the same in the formation of cells, the exuding
from them of bodies resembling pieces of jelly, and finally the
development of infusoria. ‘The only difference 1s in the character
of the infusoria, which in this case have the form of Paramecium
caudatum, rather than of Kolpoda cueullus, phases of which
present themselves in the cork infusion. There is afterwards a
development of other forms, especially a light-coloured spherical
body, which spins rapidly through the fluid, and which is similar
to organisms I have found in infusions of coal matter. The pollen
of Lscholtzia differed in its products from that of Scabious m the
absence of the fungoid growth. Instead of the fluffy appearance,
the bottom of the bottle was covered with a carpet of yellow sub-
stance, which adhered firmly to the glass. On examining a portion
of this substance with the microscope, it was found to consist of the
pollen-cells, which were apparently united by the interlacing of
very fine fibres developed from them. ‘There was, however, the
presence, almost from the very first, of the same kind of infusoria
as those which were finally developed in the other pollen infusion.
One kind, unlike the others, was characteristic of both infusions,
and I was much struck by its peculiar character, not having met
with it elsewhere. It was very simple in appearance, resembling
a short thick worm, without, however, any wriggling in its move-
ments. Other pollen—that of the fuchsia—which I have tried,
yielded results similar to those of the Scabious, in the develop-
ment in the first place of a fungoid growth, the ultimate pheno-
mena being the same as in both of the preceding cases. In this
infusion, however, there was an extraordinary development of the
spherical bodies which were produced, though in a less quantity,
from the other pollen. ‘These results are perfectly confirmed by
the phenomena observed when the contents of the anther, which
has been kept in water some time, are examined under the micro-
scope. Ifthe anther be crushed on a glass slide, it will be found
to contain, in addition to the tissue itself, a quantity of filamentous
growth, and numerous infusoria of several different kinds. In one
instance I was surprised to find what appeared to be a perfect
example of Desmidiacez, which was paralleled by the presence of
a common species of Diatomacex, among the filaments of the infused
Scabious pollen. I do not know how to account for the presence
of these organisms in this curious situation. It may be that under
the conditions named, they are sometimes developed; and on one
occasion I undoubtedly found a broad fibre, having the exact appear-
ance of an ordinary form of Desmidiacee, growing from a pollen-cell.

I have thus given a general idea of the phenomena attending
my experiments, and, in conclusion, I will shortly notice their bear-

a ee in Organic Infusions. 811

ing on the hypothesis of “spontaneous generation,” or heterogeny,
and state more fully what I believe to be the true explanation of
them. When treating of the fungus of the cork infusion, I stated
that the cell, from the contents of which the fungus spread, appa-
rently remained intact. In the case of the pollen exactly the same
thing is shown. Whatever organic development takes place, the
material of the pollen-cell, or shell, itself remains in the same state,
so far as can be ascertained. This agrees with what takes place
when leaf-tissue is experimented with, the microzymz from it being
quite independent of the material of the cells themselves, which
float about in the fluid after loss of ther contents. This fact
appears to me to prove conclusively, what all my experiments have
tended to establish, that the organic evolution of which I have
given details is not due to any process of decomposition of the
organized substance. If so, however, it cannot be the result of
“‘spontaneous generation.” One of the fundamental requirements
of heterogeny is the existence of a putrescent body in contact with
air and water. Without decomposition there can be no spontaneous
generation or organization, but when this is given the organic pro-
ducts are supposed to show themselves spontaneously — that is,
without derivation from a pre-existing germ, even in the substance
itself, which may, M. Pouchet declares, be reduced to charcoal,
before it is infused, to ensure the destruction of all organic life.
Lo me, however, such a notion as this is perfectly inexplicable.
If the infused substance does not itself contain the germs of the
future organisms, and if its organic character be thus absolutely
destroyed, what remains to impress on the infusion afterwards made
with it that peculiar character which gives rise to the phenomena of
so-called “spontaneous generation?” Nor is the experiment of boiling
the infusion more satisfactory. or, surely, if boiling will not destroy
that organic character of the fluid which is absolutely essential to its
presenting the phenomena in question, this operation must be equally
inocuous as against the organic germs that may be present in it,
although invisible. In fact, the admitted phenomena of heterogeny
disprove, so far as I can judge, the entire hypothesis. M. Pouchet
says that the granulated pellicule proligeére— la plus élémentaire
quil soit possible d’observer ”—“ est évidemment formée par des
cadavres de Monades ou de Bactériums;” * and on the preceding page
he says that this pellicule ‘est constamment formeée, dés son ori-
gine, par d’infimes microzoaires.” But whence come the first
microzoaires? The heterogenist says that they appear spon-
taneously. But from what? Not from the fiuid simply, since
without the presence of the decomposing, or rather infused, sub-
stance, the phenomena would not show themselves. Not from the
substance itself, adds the heterogenist, because “a l'état de dissolu-
* ‘ Heétérogénie,’ p. 355.

312 The Development of Organisms — [Mypninly, Mictoscorsca

tion complete dans les liquides qui la renferment, le microscope le
plus perfectionné n’y démontre absolument rien.” This, however,
is the weak point of the hypothesis, which has that purely negative
basis on which it is impossible to build with safety. Thus, it does
not at all follow that the organic germs are absent simply because
they cannot be discerned. It might as well be said that, before the
invention of the microscope, infusoria themselves did not exist, since
they were then invisible to the unassisted eye. The presence of a
decomposing organic substance, however, shows clearly how these
germs may exist in the infusion, although invisible, before the for-
mation of the pellicule proligére. For although the substance
itself may be so completely dissolved that it cannot be discovered,
the particles of which it is composed must be present in the fluid,
and if so, since there is nothing to show that they lose their organic
character, why may not the germs of the future infusoria thus
exist? In the infusions of vegetable pollen, well defined rings,
which doubtless are examples of the organic pellicule, make their
appearance long after the development of the fungi and infusoria.

The conclusion I have come to on this question, judging from
the above experiments, is simply that the infusorial germs are
identical with the particles of the decomposing substance of which
the infusions are made. ‘The monads and bacteria, whose cadavres
make up the pellicule proligere, are exactly the same, in. every
respect, apparently, as the monads and bacteria which exist in
the seeds of plants, and which give rise to the infusoria subse-
quently discovered in these seeds and in the water in which they
are placed. liven the pollen-cell is full of the merozyme from
which the monads and bacteria of the tissue are formed, and
infusoria are no less abundant when the conditions necessary for
their development are supplied. To the same category, without
doubt, belong the so-called oil-globules of milk, which also, as we
have seen, furnish numerous infusoria. The character of these
globules is shown clearly by their relation to the corpuscles of the
blood; it having been proved that milk-globules, if injected into
the arterial system, finally take the form and character of the
blood-corpuscles, which may themselves probably undergo the same
process of development as the former exhibit when infused.

In these various facts we see a connection between the animal
and vegetable kingdoms much more fundamental than has hitherto
been supposed. The peculiar position occupied by infusorial germs
in the tissue, the pollen, and the seeds of plants, shows that the
latter are absolutely dependent on the former for their development,
if not for their very existence; and, in fact, it seems to me that
whether the final result shall be animal or vegetable, depends
wholly on the conditions under which such germs are brought to.
maturity. Their nature is probably allied to that of the infusoria

a oe in Organic Infusions. 313
into which they will, in the absence of a vegetable organism,
usually be developed, although under other conditions the appear-
ance of a fungoid growth may ensue. Or, it may be said, that the
development of the organic germs in question may end in the
formation of infusoria, but that before reaching this point it may
be arrested, there being simply the formation of fresh “germs,”
the substance of the original ones appearing from time to time as
a fungoid growth, the cell-contents of which are supplied by the
renewed germs themselves.

Many curious facts bearing on this subject have been recorded
by microscopists. Such are the phenomena noticed by Dr. Hartig
and Mr. Carter, the former of whom affirms that “ Amoeba may be
produced by the transformation of the ‘antherozoids’ of Chara,
Marchantia, or Mosses; and that, in their turn, they become meta-
morphosed, first into Protococci or other unicellular Algz, and then
into articulated Algw.”* There is no improbability in these
changes, if the hypothesis I have advanced be correct. In fact,
the phenomena observed by Dr. Hartig are perfectly analogous
to those I have described—the development of low animal forms
from supposed vegetable germs. I say “supposed,” for the anthe-
rozoids of all the simple plants appear to me to be purely infusorial
germs, and they may, I have little doubt, be as readily developed
into infusoria as the contents of ordinary vegetable seeds. I have
myself obtained the Amceba under curious circumstances. If coal
be powdered and placed in water, a peculiar microscopic vegetable
growth will, after a while, be found to have been developed, and
still later numerous crystalline or jelly-like excrescences and tube-
like protuberances which have a perceptible movement make their
appearance. In an infusion of this description which I have had
for several months, I have met recently with several examples of a
beautiful form of Amoeba, and also others of a much larger kind,
which moved about among the coal vegetation, to which it adhered.
At one extremity only did those changes of form take place which
are necessary to the progress of the Amceba; there being towards
the other a circular marking, probably the contractile vesicle, and
forward movement being effected by the protrusion of a broad limb,
or rather “lip,” of a much lighter colour than the body itself, and
at the margin of which I distinctly caught sight on one occasion of
the vibration of small cilia. The development of this creature,
unless it was introduced with the water of the infusion, which I do
not believe, strongly supports the view I have taken that there is
an intimate connection between the initial phases of animal and
vegetable life.

* But see note in Dr. Carpenter’s work on the Microscope, 3rd edit., p. 357.

Monthly Mi ical
314 Plumules or Battledore Scales [Monthly, Mtcroscoplca

IV.—further Remarks on the Plumules or Battledore Scales of
some of the Lepidoptera. By Joun Watson, President of the
Microscopical Section of the Literary and Philosophical Society
of Manchester.

Havre on a former occasion (No. VIII., p. 73) drawn attention to
certain peculiar scales belonging to the Rhopalocera division of the
Lepidoptera, as serving in some degree for generic or specific classi-
fication, and having then limited my remarks to the Pieridae and
Lycenide, I now beg to state the result of observations made in
other families.

In conjunction with my friend Mr. Sidebotham a complete
treatise is in preparation, embracing the whole subject of these
plumules; it is to be illustrated with several hundreds of figures ;
but the completion of the large number of plates necessary will
occupy considerable time. The figures will be arranged in generic
groups of all the species (or so-called species) which can be
obtained, so that observers may judge whether or not the plumules
of some differently-named species are identical.|

In the first place, referring to the genus Pveris, already treated
of, I desire to draw attention to a small group of species placed at
the beginning of the genus, which display no plumules. There are
four species, viz. Thestylis, an unnamed neighbour, Clemanthe, and
Autothisbe : we have before seen that the plumules are the posses-
sion of the males only ; now, while deficient in this peculiarity,
these species have another of their own, wz. a strongly-marked
serrated costal margin of the upper wings, easily felt by running
the finger along the edge. A short time ago I drew Mr. Hewit-
son’s attention to them, expressing a wish that they might be more
correctly placed in a new genus. Mr. Hewitson had some time ago
separated this group in his cabinet, and Mr. A. R. Wallace, who is
at work on the Pieride, has done the same; and I was much
pleased to receive from him lately an inquiry respecting the absence
of plumules, showing that he attaches value to the subject. He

EXPLANATION OF PLATES XXXIV., XXXV., AND XXXVI.

PLATE XXXIV, PLATE XXX V.—continued.

Fic. 1.—Eupleea Mindonensis. ' Fig. 9.—Argynnis Daphne.
» 2— 4 <Alcathoe. », 10.—Athyma Cama.
», 3.—Heliconia Melpomene. » 11.—Taygetis Rebecca.
. ae 4 Geos
.—Eueides Thales.
” 6.—Colenis Dido. _Puate XXXVI
», 7—Pieris Lycimnia. Fic. 138.—Euptychia Canthe.
14.—Hrebia Stygne.
PuaTe XXXV. e 15.—Satyrus Berée.

ic. 7.—Agraulis Vanilla.

,, 16.—Argynnis Maia.
»,» 8.—Lachnoptera Iole.

» L7— » waglaia,

W. West imp.

©
i
FS REAM RES An TSTITyS WIT EE RN EO aN a Pe TUNE CRS SHUT ee Star 2
SSS SED RRC Ek UNL ERS OR See A EN As PSUR ee SH THE
squupwabivs er Salieieyn ies tt SN ge NU epee eer ene Ss

The Monthly Microscopical Journal, Dec? 1 1869. |

Jos. Sidebotham del. Tuffen West sc.

Flumules of Lepidoptera.

he a

ee be ee of some of the Lepidoptera. 315

proposes to call the new genus Prioneris, from the saw-like struc-
ture of the costal margin.* The only other species of Peerts which
I have examined without finding plumules are Agathon, Protodice,
and Callidice ; the absence is very remarkable in the two latter, as
their allies Daplidice and Hellica are abundantly supplied therewith.

There is a group of this genus to which I did not allude in my
first paper, being then doubtful whether its scale could be con-
sidered a plumule—that is, of a character serving for distinction ;
such scales are very abundant on P. Lycimnia, Flippantha, Isandra,
and some congeners, showing that these are perhaps all varieties of
one insect. ‘There is a figure of it on Plate XXXIV., Fig. 7; and
ereat has been my surprise to find a somewhat similar form in
some members of the Danaide family, to which further reference
will be made; these have not the bulb-and-socket apparatus.

The interlinking of affinities, and the manner in which Nature
loves to repeat her works with variations, are strikingly shown in
the plumules generally ; and throughout the different families there
may be observed assimilations of form existing in widely-separated
groups, Just as is the case in the insects themselves.

Plumule is not an appropriate name for some of the forms of
the scales which serve for distinctive classification; nor is battle-
dore, which has been applied to those of the Lycena genus; a
more universal name would be better, proclaiming their private and
peculiar property; and I would suggest Idiolepides (from iévos
private and peculiar, and ezris, a scale); but we will at present
continue the former term, plumules.

Before entering into a relation of the families and genera in
which these objects are found, let me say something about them
specially for microscopists. I have before described them as rotund
or cylindrical; but a term suggested by Mr. Sidebotham, viz.
bellows-shaped, is more characteristic and correct. It is manifest
that, if the form of plumule of P. Rapz were actually rotund or
cylindrical, the peduncle and bulb would often, on a slide, be
covered with the membrane; but, when mounted, the scale always
shows the lobes on each side ofthe bulb, proving its, in some
degree, appressed form.

Then, as to the parts of the insect where they are to be found :
generally on the upper surfaces of the wings, sometimes most
abundant on the primary, sometimes on the secondary ; usually in
or near the discoidal cells of both wings; but occasionally very
strangely placed, as we shall presently see when referring to the
genus Hupleea.

The best way of collecting and mounting is by gently pressing
the wing of the insect against a glass slide, by which means a
sufficient quantity of the scales will adhere: to get a clean mounting

* It is interesting to note that a similar serrated costa occurs in some species of
Papilio, of Charaxes, and of Gonepteryx ; and these are all without plumules.

316 Plumules or Battledore Scales — [Mputhly, Microscopical

it is necessary to brush off the dirt which may be on the wing with
a camel-hair pencil; but then care must be taken that the pencil
does not convey scales to slides of other species; and, in fact,
suspicious care must be used when mounting a number of slides, as
the light scales will often be floating in the air and alighting unex-
pectedly on the slide which is under operation. Then cover with a
thin glass, and fix with paper. In some small insects it is more
convenient to take off the scales in the first instance on the thin
cover, and then to affix it to the slide. The plumules are mostly
of so delicate a membranous structure, and so deficient in pigment,
as to become too transparent (and sometimes almost invisible) in
Canada balsam; but it may be used with good effect where they
carry some amount of pigment; and the structure of those of the
Lycenide is thereby beautifully shown, although these are among
the most hyaline. In some genera and species they are so small
and so finely striated as to make a 41-inch object-glass desirable to
resolve them satisfactorily, or at least a +, with a B or C eye-piece ;
while a 4-inch is sufficient for others.

The strive particularly should be observed with high powers.
Occasionally scales of different species appear under a low power
identical, but a higher one reveals a complete difference of structure.

Taking for our text-book the ‘Genera of Diurnal Lepidoptera ’
of Doubleday, Westwood, and Hewitson, we proceed to state the
additional families and genera where the plumules have been found.
Throughout this work there is evidenced an inkling of the writer's
appreciation of the value of the scales, or of some of them, for aid in
classification, but more in the direction of genera than of species ;
and the distinct character of the plumules is not recognized, nor the
probability remarked that the insects are furnished with two classes
of scales, as was suggested in a former article. In the consolidated
treatise we are undertaking, we shall notice, seriatim, all the
families and genera, with remarks on peculiarities of some scales,
even when they do not assume the form of plumules.

In the work above named, the Diurnal Lepidoptera are divided
into fifteen families. ‘

Family I. Partuionipm.—No plumules found.

Family II. Prerioz.—Found on many species already men-
tioned. .

Family VII. Aczronrpx.—None.

Family IV. Danarpm.—It is in the genus Hupleea only of this
family that plumules have been found ; and they bear a very different
form from that of those of other genera, with the exception of an ap-
proach in Pieris Lycimnia, Plate XXXIV, Fig. 7.* The typical
form of Huploea is shown in Plate XXXIV, Figs. 1 and 2; and I have
found them on thirteen species, whether or not all distinct may be

-- * The plates have been drawn by Mr. Sidebotham, specially for the illustra-
tion of this paper. ay

pce neat 1a. of some of the Lepidoptera. ole

questioned, but there can be no doubt about the two in the plate.
When the plates containing all the figures are ready, their simi-
larities and differences will be apparent. It is to my friend Mr.
Labrey’s industry and information that I owe a knowledge of these
plumules. I had often examined the insects unsuccessfully: and it
well might be so; for these scales are not found in the ordinary
places, but, as I believe, only in the upper part of the secondary
wings, where overlapped by the primary and fringing the light-
coloured patch on the inferior wings; here they exist in Huploa
Midamus in large and compact masses, presenting an appearance
similar to a bed of bulrushes at the edge of a marshy lake. I can-
not doubt that further search in this genus will be rewarded with
valuable evidence as to the identity or difference of many species.

Family VY. Heticontpm.—Here I have been able to find plu-
mules in the genus Heliconia only, but in twenty-six species. They
are of singular interest in our view of their use for classification and for
the determination of species. )

Mr. Bates, in his ‘ Naturalist on the Amazons,’ vol. i., p. 256,
&c. (1863), devotes some pages to show that many species of this
genus have had a common origin, proving the “manufacture
of new species in nature.” He takes “ Melpomene, abundant in
Guiana, Venezuela, and some parts of New Granada,” as the original
species, and argues that Thelxiope, “ranging 2000 miles from east
to west, from the mouth of the’ Amazons to the eastern slopes of
the Andes,” is merely a local modification; and yet he says that
“if local conditions, acting directly on individuals, had originally
produced this race or species, they certainly would have caused
much modification of it in different parts of this region; for the
Upper Amazons country differs greatly from the district near the
Atlantic in climate, sequence of seasons, soil, forest-clothing, pe-
riodical inundations, and so forth.” He then proceeds to contend
“that there is some more subtle agency at work in the segregation
of a race than the direct operation of external conditions,” and that
the principle of natural selection, as lately propounded by Darwin,
“seems to offer an intelligible explanation of the facts.”

The plumules, however, enable an observer to detect without
doubt the species: if those taken from any number of specimens of
the species Melpomene, Thelxiope, Acede, and Vesta are examined,
each can be named; but mere varieties of each species will exhibit
the same plumule, as in the case of Thelatope and Aglaope. Surely,
if the Darwinian theory were true, that a change is constantly in
progress, we ought to find plumules of an undecided form in some
specimens, partaking of and hovering between the characteristics of
their supposed ancestors. With all deference to Mr. Bates, whose
opportunities of observation have been great, I cannot but regard
his theory as improbable and far-fetched. Why should Thelacope
have descended from Melpomene rather than the latter from the

318 Plumules or Batiledore Scales [Myon stoscgpica!

former? and why suppose any necessity for derivation at all?
Butterflies are often confined to narrow localities; and when species
are widely spread in various geographical habitats, varieties occur ;
but the species continue recognizable, and the more specimens can
be obtained the more certain is their determination. It is much
more probable and philosophical to suppose that an intelligent
Creator placed His creatures in such localities and conditions as
suited their various requirements, and maintained them there; and,
as Mr. Bates says, “a proof of this perfect adaptation is shown by
the swarming abundance of the species.”

This swarming abundance and teeming variety of life in the
Amazons region is not confined to the insect tribe; for “ Professor
Agassiz, who has lately been engaged in examining the fish of that
river, states that he has not found one fish in common with those
of any other freshwater basin ; that different parts of the Amazons
have fishes peculiar to themselves; that a pool of only a few hun-
dred square yards showed 200 kinds of fish (which is as many as
the entire Mississippi can boast); and that in the Amazons itself
2000 different kinds exist.” *

We must look in vain for specific distinction, if such different
insects as Heliconia, Melpomene, and Thelxiope are to be regarded
as of one common origin. Mr. Bates admits that “both are good
and true species, in all the essential characters of species ; for: they
do not pair together when existing side by side, nor is there any
appearance of reversion to an original common form under. the same
circumstances.”

Family VI. Acrmipx.—No plumules found.

Family VII. Nympnatm.—Found in the following genera :-—

Eweides.—Here on five species they have been detected, and
they bear a very strong similarity to those of the Heliconidx, the
insects themselves being also alike. A comparison of Helicoma
Vesta and Hueides Thales would induce a casual observer to regard
them as almost identical; but Mr. Hewitsont has pointed out “a
difference in the position of the discoidal nervures of the posterior
wing, as well as in the orange rays which proceed from the base of
the posterior wing ;” and he well says, “If a butterfly or a genus
resemble another (though placed systematically at a distance from
it), let it be in colour or in form, it may be expected to resemble it
in other characteristics.” The plumule of Hueides Thales you will
see on Plate XXXIV., Fig. 5.

Colenis.—Found in five species, one of the forms being shown
on Plate XXXIV., Fig. 6.

Agraulis.—Found in three species, introducing a very distinct
type, which we shall see is, as it were, played upon and repeated
with variations in other genera (Plate XXXYV., Fig. 7).

Terinos.—On the two species of this genus which I possess

* « Athenzeum, March 23, 1867. t ‘Journ. of Ent.,’ vol. i. p. 156.

—

Microscopical Journal Dec*1 1869.

The Monthl

og

Jos. Sidebotham del. Tuffen West sc.

of Lepidoptera.

Plumules’

hoo

yt

i

u

yea

res,

Leen te.
Fast nN

yar
Aaa

Monthly Microscopical

Journal, Dec. 1, 1869. of some of the Lepidoptera. 319

there is a very peculiar pear-shaped scale, not, however, I think, a
plumule. I notice this genus here in its place because it possesses
hairs of a bifid form at the apex, of a character similar to some
which will presently be noticed under the genus Argynnis.

Lachnoptera.—This genus consists of a single species, “ Tole ;”
and its very peculiar scale is shown on Plate XXXV., Fig. 8. It
was noticed by Doubleday, who regarded it as probably of a sexual
character, although he had never seen a female; nor have I. He
describes it as “a hair-like scale, terminating in a vane, like the
feathers of the raquet-tailed humming-birds.”

Argynnis.—Plumules found on fifteen species. They have often
been noticed by microscopists; and two were figured in the article
by Deschamps, to which reference was made in my first paper.
The type is shown on Plate XXXY., Fig. 9, and Plate XXXVI,
Fig. 17. Besides these plumules, however, there are found on some
species some plumule-like hairs, as shown on Plate XXXVI, Fig. 16.
Many of the Lepidoptera possess fringes of long hairs, but with a
simple pointed termination, while these have a large brush at the end.
I doubt whether they should be regarded as serviceable for specific
distinction; but further examination is desirable. It is strange
that I have not succeeded in finding plumules on any individuals of
the second section of the diurnal species of this genus, nor on any
of the very closely allied genus “ Melitxa.” These two genera have
been much mixed together by entomological classifiers. Will the
presence or absence of plumules serve for a permanent separation ?

Athyma.—Plumules have been found on eleven species, a type
_ being shown on Plate XXXV., Fig. 10. I have searched in vain
for them on the closely allied genus Neptis. There has been great
difficulty in the generic separation of this group ; but perhaps here-
after the existence of plumules may aid classifiers with regard to
the allied genera Athyma, Neptis, and Limenitis.

Hteona Tisiphone.—This insect, although placed among the
Nymphalidz in our text-book, belongs no doubt to the family
Natyride, as 1s now generally admitted, and as its plumule would
serve to prove.

Thus we see that in the large family Nymphalide plumules
have been discovered in but few genera, and those principally of the
sub-family Argynnidz of some authors.

Families VII. and IX. Morrnipz and Brassotipx.—No
plumules.

Family X. Satyrmm.—Here we have generally a well-marked
type, subject, however, to many aberrations.

Corades.—F ound in three species.

Taygetis—Found in four species. Plate XXXV., Fig. 11,
exhibits the form of the plumule of 7’. Rebecca, reminding us in its
outline strongly of Pzeris Belladonna ; the strize, however, are very dif-
ferent; and this group does not possess the bulb-and-socket apparatus.

320 Plumules or Battledore Scales, {Monthly Microscopical

Zophoessa.—Found in one species.

Euptychia.—¥ound in five species. See the singular. form of
that of Canthe, Plate XXXVI., Fig. 13, reminding us again, by its
large lobes, of some of the Preridz.

Erebia.—Found in thirteen species. A type shown in Plate
XXXVI, Fig. 14.

Chionobas.—Found in seven species. A most interesting
northern group, principally inhabiting Lapland and Norway.

Lariommata.—Found in ten species, the forms of Mera and
Megzra having been figured by Deschamps.

Satyrus.—Found in thirty-two species. <A type, Beroé, is
shown on Plate XXXVI., Fig. 15. The plumule of Janira has
long been known.

Families XI., XII., and XIII. Evryreninz, Lisyruer2,
and Exvcrsipx.—No plumules found.

Family XIV. Lycxx1pm.—To these battledore san I have
before called your attention.

Family XV. UHsespertpm.—None found.

Having thus completed an account of observations already made,
I annex a Table showing an approximate estimate of the number of
species where plumules have been found to exist, and of the genera
possessing them. Doubtless there is room for further research; and
I would urge upon all a prosecution of this interesting study. I
doubt not that among the Rhopalocera there will be further dis-
coveries made; and the Heterocera afford an untravelled field to an
observer. It will be very interesting to entomologists to learn
whether any plumules are to be found among them, or any other
class of scales serving for generic or specific classification.*

GENERA IN WHICH ISTHE HAVE BEEN FOUND.

Species. Species.
Euterpe, about 19 Athyma ..... 11—Nymphalida 45
Pontia. 4... <): if | Corades ey
Pieris in oie on Taygetis . 4
CP TIS a os Nese eee Pronophila 9
Anthocharis .. 29 Debis 2 Lee
(hestias 1.) 2.3 14 Zophoessa 2 Ae
Hebomoia .. 3 Euptychia 5)
Eronia ... |... * di—Pierids .. 201. |Hrebia +12. aie
Euplea .. .. 15—Danaide.. 15 | Chionobas pict,
Heliconia.. .. 26—Heliconide 26 | Lariommata .. 10
Eueides 6 Satyrus eles 30. Satieidlel 89
Coleenis 5 Lycena ..- ., 121
Agyraulis .. 3 Danig’ o...aee
Terinos 2 Dipsas .. .. I1—lLycenide 131
Lachnoptera 1 —_—
ATS YNMISi se La 30 Genera. 507 Total .. 507

* This article has been reproduced—with permission—from the ‘ Transactions
of the Literary and Philosophical Society of Manchester.’ The stones have been
kindly lent by the author.—Ep. M. M. J.

The Monthly Microscopical J ournal, Dec? 1.1869.

W West imp.

JosSidebotham del. Eiffen West sc.

Phimules of Lepidoptera.

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mourns Dee ios | Use of various Microscopes. O21

V.—My Experience in the Use of various Microscopes.
By Dr. H. Hacen.*

Havine worked with the microscope more than thirty years for
medical and scientific purposes,—following the gradual perfecting of
the instrument—lI was anxious to examine the power of American
microscopes. But my occupation in the Museum and ignorance of
the English language have prevented the accomplishment of my
wishes. I ordered a new microscope of M. Hartnack in Paris,
which was kindly forwarded to me by M. Milne-Edwards. The
French instruments are noted throughout Europe for their power
and finish, and in order to judge impartially, I chose one of these,
rather than a German instrument. It is well known that nearly
every nation claims for itself the highest degree of perfection in
the manufacture of microscopes. No Englishman would acknow-
ledge the superiority of a French instrument, nor a Frenchman
that of an English instrument.. In Germany alone, Prussian,
Austrian, Saxon, and Bavarian manufacturers all claim pre-emi-
nence for their respective instruments, not only compared with each
other, but with those of American and English manufacture. There
has been no unanimity of opinion among scientific men in regard
to this question. I think these conflicting claims are based upon
something beyond mere national pride. In fact, microscopes finished
by the most skilful opticians, have arrived at a high degree of per-
fection in nearly every country, and differ less than is generally
supposed, During the past ten years there has been great compe-
tition among opticians, but in every case their progress has been
arrested by one insurmountable obstacle. Since the recent improve-
ment in correcting the objectives for the thickness of the cover-
glasses, comparatively little has been done. Indeed it is always
stated and accepted as a fact, that the proper means of obtaining
a stronger power consists in securing a higher power of the objec-
tives and a smaller focal distance with greater angular aperture,
and in this opticians have arrived at a rare degree of perfection.
Objectives of 1th in. are made, and the greatest angular aperture,
so far as I know, is in the ~yth objective by Spencer, with 175°
angular aperture. But even here further progress is arrested. The
increase of the angular aperture increases the two aberrations to be
corrected, and materially weakens the penetrating power. Judging
from an examination of the test-plate of Nobert, it would appear
that the best instruments of any country differ but little in power.
Tt was stated, at a recent meeting, that Messrs. Stodder and Green-

_* The following paper was read before the Boston Society of Natural Science
on the 10th of March last. We reproduce it because it contains an interesting
sketch of the qualities of different instruments not generally familiar to English
workers.—Ep. M. M. J.

VoL. Il. Z

322 Use of various Microscopes. — [Monthly Micrescoptcal
leaf had resolved the highest groups, a thing never before accom-
plished with any instrument. This statement, however, is doubted
by their learned countryman, Dr. Woodward.

The test-plate of Nobert, dividing the inch into more than one
hundred and twelve thousand parts, is generally adopted as a
good test-object. But even here a very important consideration in
forming a thorough and correct judgment exists, and is almost con-
stantly overlooked; I mean the difference in the aberration of the
eyes of the observers. There is no doubt that different observers
obtain different results from the same instrument; of course a
greater dissimilarity arises in the use of the same test-object with
separate microscopes. All attempts to correct this personal aber-
ration are still unreliable and unsatisfactory ; therefore the micro-
scopic photographs which are brought to so admirable a degree of
perfection, are, in fact, the surest test-objects now existing for the
power of an instrument.

Besides this personal difference there exists a very considerable
one resulting from the continual use by each observer of one par-
ticular instrument. In this connection I recall the striking fact,
that as the celebrated microscope of Leeuwenhoek arrived at the
Royal Society in London after his death, no one was able to see the —
objects observed and described by him. An experienced observer
will often see much better with his own imperfect instrument, to
which he is accustomed, than another person would do with a far
Superior microscope. .
~ Doubtless the most important matter for microscopical science
is the price for which the instrument can be obtained. The cheaper
the instrument the larger the number of observers. In Europe, ten
years ago, about two thousand large instruments were manufactured
every year; now the number is more than double. Surely for
a physician, and for many other observers, an amplification of
moderate size, from two hundred and fifty to three hundred dia-
meters, is sufficient. Professor Ehrenberg, in Berlin—and I believe
no living observer has made so much use of the microscope—
uses almost constantly in his work an amplification of three hundred
and fifty, and in some exceptional cases of seven hundred and fifty
diameters. For histological purposes higher amplifications are
necessary, but the physician and the naturalist will usually be con-
tented with a good amplification of nearly three hundred diameters.

Every possessor of a microscope wishes to test the power of his
instrument, but it is not, and never has been, my purpose to pro-
voke competition between American and European microscopes.
Certainly every step toward the perfection of the microscope is
important, but when the improvements are so minute that they
eannot be used and seen easily and everywhere, they are, I think,
more interesting to the artificer than to the operator.

i hg ee Use of various Microscopes. 323

Indeed all over the world, first-class microscopes have resolved
the fourteenth, or even the fifteenth band of Nobert’s test-plates ; but
should it be found that American microscopes, even with a }th in.
objective, have resolved perfectly the nineteenth band, the superiority
of these instruments would be so enormous that it could easily be
proved in any place and at any time.

I wrote to Mr. Hartnack to send me a first-class microscope for
investigations in anatomy and natural history, and added that I
intended to compare it carefully with the best American instruments.
I did not fix the price, and left the choice entirely to him.

He has sent the instrument marked in his catalogue as No. VIII,
a new small model, only differing from his great model by wanting
the rack motion of the tube, by having but three eye-pieces, and
by lacking two objectives of lower power.

The catalogue states that this new model, Hartnack’s patent,
differs materially in the optical and mechanical construction from
his old Oberhauser microscope. I confess I have been unable to
discover any difference, except that the fine moving screw is placed
near the top of the tube instead of below. The sliding tube to be
elongated by another tube has a diaphragm, which is also above the
objective. The diaphragm under the stage may be removed by a
sliding apparatus or by a sliding tube. ‘The three eye-pieces, as in
the Oberhauser instruments, have a low power, 24, 34, 54 nearly.
The objectives are No. IV. 4 in., No. VII. jth in., and No. IX.
yth in., fitted for correction for the cover-glasses, and for immer-
sion. Hartnack calculates the amplification for the first ranges
from 70 to 480 with the lower eye-piece, and from 140 to 950
with the strongest. The camera lucida used with a fourth eye-
piece goes up to 1000 times. ‘The lowest eye-piece has a glass
micrometer. |

This instrument costs 390 francs, about 104° 00 dols. in currency,
and the camera and lens, 50 francs, about 14°00 dols.

The catalogue sent with the microscope gives numbers of the
objectives from 10 to 18, or from }; to 35 inch. The +, costs 200
francs (538 dols.), the 5, 500 frances (134 dols.), and the other
numbers vary accordingly.

The two stronger eye-pieces, 5 and 6, cost ten francs each.
No. 5 magnifies 74 times. No. 6 is unknown to me.

My instrument is No. 8066. Nineteen years ago, in March,
1850, Professor Vrolik received from the same optician No. 1786.
Since then he has delivered 6280 microscopes, 330 a year, or almost
one a day. My instrument was received about six months after I
ordered it.

The Section may be interested in seeing an old German micro-
scope, made in Berlin by Scheck, in 1837, and used by me for
many years. ‘The defining power is even now sufficient, but the

Z 2

324 Use of various Mieroscopes. | Moninis, Microscopical
penetrating power in all microscopes at that time was very low. In
the old Nobert’s test-plate of ten bands, it resolved the sixth well,
but the seventh is doubtful .At this time Scheck’s microscopes were
considered the best by the most experienced observers, especially
by Ehrenberg. Iam sorry I cannot exhibit a microscope in my
possession, nearly two hundred years old, and now in good order.
I have watched with great interest the growing demand for these
instruments, and the surprising increase in the number manufac-
tured during the last thirty years. Long ago I made my first
observations on the scales of Lepidoptera and Coleoptera, with an
old English microscope, perhaps of Martin, and only partly achro-
matic. Since then I have used first-class microscopes of Ploesl, then
those of Scheck (none of them is sufficient to show the transverse
lines on the scales of Lepidoptera), later of Oberhauser and Nachet.

From this time almost every European naturalist gave up using
microscopes mounted upon high stands, as observations with high
objectives are more easily and accurately made in a sitting position,
when the arms can be supported upon the table. The end is not
attained by placing a microscope with a high stand upon a low table,
because the hands are less readily guided at a distance from the eyes.
The English opticians appreciated this, and arranged a strong wooden
transverse rest for the hands, even in single microscopes.

I have noticed that foreign students entering the Institute for
Pathological Anatomy, very soon exchange their high-stand English
microscopes for short-stand instruments, and even here I was not
surprised to see the Professor of Pathological Anatomy using a
short-stand French microscope.

Doubtless every observer will handle his own instrument to
greater advantage, but for certain purposes particular constructions
are preferable ; and indeed I know of no work that would actually
require a high-stand microscope. I am the better able to judge,
having examined microscopes of this kind in Germany and England,
especially those of Fraunhofer, Ross, Smith, Amici, and others. It
may be interesting to mention that Nobert’s instruments are not
considered superior. J have examined a first-class microscope with
an objective fitted for correction, and calculated by him to have a
power of 500 diameters. The marked yellow light in the Nobert
microscopes is very trying to the eyes. ‘The mechanical work is
good, but not remarkable. A kind of screw for fine motion used
by him is perhaps unknown. A long, strong, steel screw is used ;
the upper half of the thread of which is turned in the opposite
direction from that on the under half, and the two halves differ
somewhat in size. By this arrangement the motion of the screw
moves the instrument only as far as the difference in the fineness of
the two halves, and with a strong screw a very fine motion is
obtained, and “dead point” is impossible.

WIG, Dee ets Use of various Microscopes. 320

The Trichina spiralis has singularly forwarded the manufacture
of microscopes. very physician and many other persons engaged
im examining pork, tried to obtain a microscope as soon as possible.
At first the manufacturers could not possibly meet the demand.
Consequently the manufacture of these instruments has everywhere
increased, and one can get a very good French or German student’s
microscope, amplifying 250 to 300 times, for twenty-five dollars. I
have seen instruments with a power of 150 to 200 times for twenty
dollars, or even less. The increasing number of instruments has
been very advantageous to science, and I hope that the calamity of
trichina, even now fearfully prevalent in Europe, will be compen-
sated by a marked progress in science.

Monthly Mi ical
( 326° ) Journal, Dec. 1, 1869.

PROGRESS OF MICROSCOPICAL SCIENCE.

The Double Plate of Aulacodiscus oreganus. — From the proof-
sheets of the Proceedings of the Boston Society of Natural Science
which have reached us, we learn the following particulars of some
communications on the above subject made to that Society in the
course of this session by Mr. R. C. Greenleaf. Referring to the fact
that Mr. Charles Stodder had already called attention to the double
plate of the various disk forms among the diatoms, he mentioned that
Mr. E. Samuels, in preparing a single specimen of Aulacodiscus orega-
nus, after placing it on the slide, found that it had divided, the upper
shell slipping off from the under. This, he said, is the most perfect
specimen of the division of this class of diatoms he had ever seen, and
the most authentic, as the divisions really took place under the eye.
This is a very interesting object, because it proves, if proof were
needed, that these disks are formed of two shells, and thus conclu-
sively reveals the fact that many species have been named by micro-
scopists as new, that are only the thin under-layers of the shells of
species already classified. Mr. Greenleaf is confident that many
of the species named by Dr. Greville, although he was one of the
most skilful and diligent. of observers, are merely these thin shells
removed from their connections, In the January number of the
‘Quarterly Journal of Microscopical Science,’ there is a figure given
by Dr. Greville exactly like this under-shell, which he calls Aulaco-
discus orientalis. Since writing the above remarks Mr. Greenleaf had
seen a letter from Professor Eulenstein to Mr. Charles Stodder, in
which he alludes to the paper of Dr. Greville on Aulacodiscus orien-
talis. Professor Kulenstein at first thought, as he did, that A. orien-
talis was the inner plate of A. oreganus, but after a more careful
examination of the form, decided it was a new species. He had a
slide containing the object. Mr. Greenleaf had only seen the drawing.
Mr. Stodder is of the same opinion. He says that the granules in
A. orientalis differ in form from those of A. oreganus, being square or
oblong, and not arranged exactly in the same order. This last vari-
ation Mr. Greenleaf noticed in the drawing, but by a careful adjust-
ment of the focus, the variation in this particular is small. Professor
Eulenstein says there is a chance of error in examining these disk
forms, in mistaking an immature frustule, separating from the parent,
for the inner plate. Mr. Greenleaf would be inclined to hold to his
first impression, but said he must defer to higher authority at present.

The Preservation of Sections of Brain and Spinal Cord.— Concern-
ing Dr. Bastian’s paper on this subject, which appeared in one of our
earlier numbers, Mr. Alfred Sanders, M.R.C.S., has addressed the
following letter to ‘Scientific Opinion’ (Nov. 24th) :—

“ Allow me to call the attention of those of your readers who are
interested in microscopical investigations, to the use of creosote for
this purpose: it was recommended by Dr. Ludwig Stieda, in Max

settee Derseaeical] PROGRESS OF MICROSCOPICAL SCIENCE. 327

Schultze’s Archiv for 1866, Bd. ii. Heft 4. I have tried it in compari-
son with Dr. Bastian’s process, and find it at least equal, and, I may
Say, permanent, as I have sections of the brain of conger, made more
than a year ago, which now show every nerve-fibre and cell in great
perfection. Its manipulation is extremely easy, the brain, or other
structure, being, as usual, hardened in chromic acid ; the section is put
for a short time in spirits of wine, and thence transferred to the creosote,
which makes it transparent in a few minutes; it is then placed in
Canada balsam. ‘The balsam will m:x casily with the creosote, or
the solution in benzole may be employed. As Dr. Bastian did not
mention this process in his paper above referred to, I presume that it
is not generally known in England, which must be my apology for’
occupying your space with this communication.”

The Anatomy of the Reproductive System.—In a paper read in June
last before the Royal Académie of Vienna, Herr Gussenhauer described
a new method he had devised for the microscopic study of these struc-
tures. It consisted in making a series of vertical sections, and it did
not elicit any new points in structure. It is chiefly of interest from
the fact that the author uses oil of cloves in preserving his specimens,
and finds it answer very well.

- The Homologies of the Polyzoa.—Mr. Alpheus Hyatt’s paper on
this subject, which was read in August before the American Associa-
tion, is thus summarized:—The Embryology of the Hypocrepian
Polyzoa shows that Loxosoma is the lowest of all in the order, and
together with Pedicellina form the lowest suborder of the group. The
progress of the whole order of Polyzoa is from this permanently in-
vaginated form through intermediate stages to Cristatella, in which,
when the polypide is inserted, even the stomach is carried up beyond
the orifice of the cell. Thus the progress of structure is from an
animal in which all the organs are crowded into the anterior end, into
the coeneecial system, and to one in which the ccencecial or repro-
ductive, evaginatory or gastric, and the lophoric or neural systems
are all distinct when the animal is exserted. The Polyzoén may be
transformed into a Brachiopod by simply enlarging the ccencecial
wall and carrying it over, enclosing the lophophore and reversing the
position of the arms. Thus both the Polyzoa and the Brachiopods
may be defined as sacs, closed at the posterior end by disks surrounded
by tentacles, and perforated by an edentulous mouth, from which hangs
the alimentary canal in the antero-posterior axis of the sac. The
whole plan of the Mollusca was stated to be that of a simple sac, and
the term Saccata proposed as more appropriate than that of Mollusca.
The objection that the whole animal kingdom may be said to be sac-
like has been raised. The Radiata are, it is true, radiated sacs, the
Articulata ringed sacs, and the Vertebrata sacs divided by the verte-
bral axis, but the Saccata are typically sacs.

Monthly Microscopical
( 328 ) sousiell Dec. 1, 1869,

o

NOTES AND MEMORANDA.

New Cheap and Good Foreign Objectives.—It is alleged by Dr.
Benscke that a young optician named Gundlach, of Berlin, has suc-
ceeded in making object-glasses, which are cheaper and more powerful
than those of Hartnack and other opticians. His No. 7 is better than
Hartnack’s No. 9 or No. 10, at less than half the price of the No. 9.
It has higher magnifying power, more light, and greater focal distance.
Max Schultze says that Gundlach’s No. 8 is better than Hartnack’s
No. 14, and is only a third of the price.

Mr. Moginie’s New Strainer for Collecting-bottles.—In the
notice of a New Strainer for Collecting-bottles, at page 286 in our.
last number, for Mr. Maginie, 37, Queen Square, read Mr. Moginie,
385, Queen Square, W.C. [The erratum occurred in the Report of the
Old Change Microscopical Society. |

A Simple Form of Cell—Mr. W. Beavan Lewis gives in ‘Science
Gossip’ the foll6wing as an easy and effective method of making
cells :—Purchase a box of endless elastic bands, and the addition of a
jar of Brunswick black will now supply all the requisite material for
the formation of a large stock of good and neat cells. Slip one of these
bands on to the blades of a pair of scissors, slightly opening the latter
to keep the band near the points, and prevent it from slipping off;
now paint it over with a thin layer of Brunswick black, allow the
band to fall flat on the centre of a glass slide, fix your object, and
gently place your thin cover over it, which will firmly adhere to the
band: this is cell No.1. For cell No. 2 another band is slid on to
the scissors after the first band has been painted; the pressure of a
forceps will cause them to adhere, and now you have your cell double
the depth of the first. The bands which I use are half an inch in
diameter, and with these the deepest cell advisable to be made is that
of three bands ; should a deeper cell be required, bands of a larger
diameter are necessary. I have a large number of objects mounted in
this way, the majority being dry preparations, but I find this cell is
equally serviceable for mounting in glycerine or Goadby’s solution.

Dr. Lionel Beale on Protoplasm.—We understand that a second
edition of this work is just about to be issued.

The Origin of Life.—Those who wish to see an able detailed and
dispassionate review of the facts and arguments for and against
Heterogeny, should consult a series of papers under the above title in
the recent numbers of the ‘ British Medical Journal.’ They are, we
believe, from the pen of a distinguished Fellow of the Royal Micro-
scopical Society.

Mr. Stephenson’s New Safety Stage.—The following is a de-
scription of this ingenious contrivance, exhibited at the last meet-
ing of the Royal Microscopical Society. The “Safety Stage”
consists of a thin frame of brass, with thicker pieces screwed on at

“yeteaal, wee oe NOTES AND MEMORANDA. 329
the two front corners, to which is hinged at AA (Fig. 1) a second

frame, also of thin brass, which supports the object or slide-holder.

Fic. 1.

—s

<=
a>

These frames are kept asunder at a distance of about ,3,ths of an inch
by light springs B B, which can be made so light as to carry as little
beyond the weight of the stage as is wished — the hinges being so
constructed as to keep the frames parallel, a result which is also
effected or supported by the heads of two steady pins at the back of
"the stage.

The object is carried on the two arms C C, and is held in its place
by a spring placed over and between them, this form having been
adopted for greater facility in using the modes of illumination re-
cently introduced by the President of the Microscopical Society,
and by Messrs. Powell and Lealand; the former by the use of an
equilateral prism, and the latter by a pencil of light from a small
lens of short focus: the whole slides
on to the present primary stage with
a dovetail-piece.

In focussing down on an object
placed on the safety stage, should the
worker proceed too far, the upper
part of the stage yields instantly to
the pressure, and the object recedes.
This should in itself be generally
warning enough, but as it might not
in all cases be deemed sufficient se-
curity, Mr. Stephenson has introduced
a second and very simple instrument
(Fig. 2) to act as a stop. This con-
sists of a square rod of brass, marked
on one face with lines, showing the
height to which it must be adjusted to
suit the various object-glasses used :
it is held in its place by a pin passing
through it, which is attached to a screw at the outer side of the
socket in which the rod slides. This little instrument is placed,. in

Fig. 2.

330 -\ QORRESPONDENCE, Bee eee

Ross’s form, beneath the bar which carries the body of the microscope,
and whilst permitting the front of the objective to touch the object
on the stage, even to press it down by acting on the springs, will
arrest all progress in this direction, before the upper part of the stage
has been pressed upon the lower; thus, how careless soever a person
may be, or however great may be the force used, the pressure on the
object-glass, as on the thin cover of the object, is limited to the
strength of the springs used, which may, as previously stated, be made
as light as is desirable.

The want of such an arrangement is much felt by all persons
using very high powers, and more particularly so now that the immer-
sion system is coming more into vogue; and under this, we lose the
benefit of the surface of the thin cover, as well as the dust, which,
under the dry system, acts as a friendly beacon.

With the safety stage, not only will persons work with more con-
fidence, but members of the Royal Microscopical and other Societies
will be enabled to exhibit objects of interest under the highest powers,
which they have hitherto in most cases been afraid to do.

CORRESPONDENCE.

UntversaL Mountina AnD Dissnctina Microscope.
To the Editor of the ‘ Monthly Microscopical Journal.’

BirmincHam, November 10, 1869.

Srr,—In a former number of the ‘ Microscopical Journal’ (J une),
a description was given of a mounting and dissecting microscope that
I had designed as a microscopist’s companion, for enabling any one to
carry in a single small case, whenever going into the country or to the
seaside, a dissecting microscope with special arrangements for facilita-
ting the mounting of objects; and a complete set of the apparatus and
materials required for mounting, combined with a compound micro-
scope good enough for ordinary requisites. This instrument has
been referred to in a letter in a subsequent number of the Journal,
in which there appears to have been a misapprehension in reference
to the origin of the instrument.

In justice to the makers, Messrs. Field, of Birmingham, it should
be stated that as regards the design of the case (the point specially
referred to in the above letter), and the optical work, the whole credit
is due to the makers so far as I. am concerned, as the instrument was
put into their hands to complete it in a portable and finished form.
This object has certainly been ably and satisfactorily carried out by
them, and they state that they are not aware of having derived any
part of the idea from the writer of the above letter.

My original idea in the instrument was an endeavour to combine
the advantages of Messrs. Beck’s and Dr. Lawson’s excellent dissect-
ing microscopes, with a complete set of the apparatus and materials
required in mounting objects; including the accessories of turn-table

he PROCEEDINGS OF SOCIETIES. 331

and hot-plate, &c., which ordinarily occupy too much space to be
compatible with great portability and compactness. A number of
these instruments are now in use, and they are found very convenient
for supplying a desideratum that I believe has not before been met ;
and they have been made very complete by improvements in the
working-out of the details suggested by several microscopic friends.

Wituram P. MarsHatu.

PROCEEDINGS OF SOCIETIES.*

Royaut MicroscopicaAn Socrery.

Kine’s CoLuece, November 10, 1869.

The Rey. J. B. Reade, F.R.S., President, in the chair.

The minutes of the previous meeting were read and confirmed.

A list of donations made to the Society was read, and a vote of
thanks passed to the various donors. Special mention was made by
Mr. Slack of a very interesting present to the Society by Dr. Millar,
in the form of a fine specimen of an Amici reflecting microscope, the
objectives of which were like miniature Newtonian telescopes. The
present had acquired additional value by the gift on the part of
the President of three powers adapted to the instrument.

A special vote of thanks was given to Dr. Millar and the President.

Mr. Slack also announced that Mr. Collins had presented to the
Society an improved form (modified by Mr. Brooke) of his double
nose-piece, the apparatus having been so constructed as to reduce the
weight and lessen the price.

Mr. Slack exhibited on behalf of Mr. Blankley, F.R.M.S., a new
polarizing apparatus devised by him, containing a sliding wedge of
selenite working under a circular rotating-plate of the same material,
and affording gradations of tint.

The President announced that Mr. Stevenson had brought for
exhibition his new safety stage, which effectually protected the most
delicate object-glasses and objects from injury. It consisted of a brass
frame adjusted so as to allow the objective to come down just as far
as the covering-glass of the object, but no farther. [For description
and figures, see “ Notes and Memoranda.”

A vote of thanks was passed to each of these gentlemen.

Mr. Hogg exhibited a new portable microscope by Mr. Collins,
describing it as most convenient in form, and of very ingenious con-
struction.

Dr. Pigott, who had intended to read his paper on “ High Power
Definition, with illustrative Examples,” being unavoidably absent, the
President requested Mr. Slack to read the communication. Mr. §.
McIntyre having written a paper on a cognate subject, ‘The Scales

* Secretaries of Societies will greatly oblige us by writing out their reports
legibly—especially the technical terms—and by “underlining” words, such as

specifie names, which must be printed in italics. They will thus ensure accuracy
and enhance the value of their proceedings.—Ep, M. M. J.

Monthly Mi ical
332 PROCEEDINGS OF SOCIETIES. pathy Mee

of certain Insects of the order Thysanura,” the President called upon
Mr. McIntyre to read his communication before proceeding to the
discussion.

Mr. J. Beck said the view his late brother held as to the structure
of the Podura scale was that the markings were caused by wedge-
shaped elevations running from the quill to the apex of the scale.
He had himself paid great attention to the scales of Thysanurade,
with a view to ascertain their structure. He hoped that microscopists
would discontinue the use of the name “ Podura” scale, as it involved
great confusion, the apparent structure of the scales of different
genera in them not being the same; and he hoped in speaking of the
genera from which test-objects are taken that the scientific name of
Lepidocyrtus curvicollis would be adopted. He thought that in order
to ascertain the structure of the scales of this family, especially of
those species possessing delicate scales, the structure of all must
be taken into account, and assuming that the structure of all was
similar in plan, determine whether the individual appearance was con-
sistent with this idea. In Lepisma saccharina the appearance was
undoubtedly due to corrugations on the one side running from the
spine to the apex; to corrugations on the other side radiating from
the spine to the circumference ; this structure producing the appear-
ance so familiar to observers. ‘The correctness of this idea of the
structure could be easily tested by running moisture on either side,
as explained in his brother’s work on the microscope. In Petrobus
maritimus there was, as might be proved by experiment, the’ same
structure with but slight variation, and the same might be said of
Macrotoma, of which Mr. McIntyre had spoken. 'To ascertain whether
the appearances in Lepidocyrius curvicollis were consistent with the
existence of lines, he had examined many butterfly scales having cor-
rugations, and selecting those of the Peacock butterfly as the most
suitable, found that where the scales overlapped one another at about
an angle of 30° the lines were obliterated, and the “ notes of exclama-
tion” appeared. 'To resolve this object he considered almost as good
atest as L. curvicollis. He thought there was prima facie evidence
that appearance on the test-scale was due to a like cause; but he had
reason to modify his opinion, for observation had shown that the
structure of the two sides of the scale was different. If a piece of
glass be laid on the insect, the scales adhering would have their under-
side uppermost, and if breathed upon while under the microscope,
moisture would be seen to run up and down along corrugations, as in
LL. saccharina or Petrobus ; but if this experiment be tried on the upper
side of the scale the moisture would spread over the surface, and
present the appearance of an undulating membrane. He inferred
from this that the structure of Lepidocyrtus scale was similar to that
of other genera in this group, slightly varying in the corrugated and
undulating appearances; but still that in Lepidocyrtus as in Lepisma,
the true structure on the under-side of scale is a series of corruga-
tions on one side, and that the other side was slightly undulating, or
nearly smooth; and that the “notes of exclamation” were due
entirely to the refraction of light. This idea’ was confirmed by the
appearance of the scale when the object-glass was out of focus.

an Dee es PROCEEDINGS OF SOCIETIES. 333

Mr. Beck then alluded to the different views entertained by micro-
scopists on the structure of the scale, and expressed his belief that if
the Fellows would adopt the plan he had described they would agree
with his conclusions.

Mr. Browning explained, in answer to an inquiry by the Presi-
dent, that Dr. Pigott had been kind enough to show him the markings
he had observed, of which he (Mr. Browning) made a diagram.
But beyond this he had been entirely ignorant of the contents of
Dr. Pigott’s paper until he had heard it read that evening. He
thought it right to mention that Dr. Pigott had dispensed with a
condenser, and illuminated the objects by the common lamp flame.
Mr. Browning also said that the eye-piece used by Dr. Pigott was a
very deep one, but he was not acquainted with its construction. He
(Mr. Browning) remembered that in a discussion in which he took
part with Sims, Dallmeyer, and Prichard, that they all agreed that the
diffraction-rings of the stars to which allusion was made by Dr. Pigott
were due to the undulations of light, but if the object-glass were well
made no perceptible difference in the diffraction-rings would be
remarked. In reply to a question from Mr. Slack as to whether it
was not a fact that in the case of two telescope glasses, the one well
corrected, the other having a considerable residue of spherical aber-
ration, that the well-made glass would show the diffraction-rings clear
and sharp, and in the other they would become intermingled and
indistinct. Mr. Browning said that it was undoubtedly the case.

Mr. Hogg said he thought Dr. Pigott in error in what he had
stated in regard to the marking on the Podura scale. He believed
that Mr. R. Beck was nearer the truth in his view of the structure of
the scale, especially as the experience of Mr. McIntyre confirmed his
opinion. He (Mr. Hogg) had a great objection to the use of too deep
an eye-piece, as it tended to increase errors; and he believed that this
was one cause of the mistake into which Dr. Pigott had evidently
fallen. He had also erred, he thought, in the method of illumina-
tion employed, for by using the direct flame of the lamp without any
means of correcting the illuminating pencil, he would experience
considerable disturbing power. He objected also to Dr. Pigott’s
mode of obtaining magnifying power by increasing the length of the
body of the microscope. Moreover, it was well known that as age
increased and presbyopia set in, the eye was often the subject of certain
elements of visual disturbance. He thought some such disturbing
element had led Dr. Pigott to believe that the appearances which he
had represented were something entirely new. He (Mr. Hogg) had
examined the scales with immersion lenses, and failed to discover
anything at all resembling that which Dr. Pigott had described in
his paper.

The President said he quite concurred in the observations made
by Mr. Hogg, and he was only sorry that Dr. Pigott was not present
to make a reply. He could not but feel (such was his confidence in
the skill of the opticians of the day) that what he saw with their
instruments was that which really existed, and that he had a clear
and correct view of the objects under examination. With respect to
Podura scale, he believed that Mr. Beck’s description of the outline

Monthly Microscopical
Journal, Dec. 1, 1869,

304 PROCEEDINGS OF SOCIETIES.
was accurate, being what geologists would call the bluff-and-tail
escarpment; and that the other portion under the spherules has a
definite existence, as is proved by the beautiful observations of
Mr. Wenham, who has shown that on a dark-ground illumination
these little spherules appear like distinct and beautiful light circles,
and this view of the object was entirely different to that usually seen
by microscopists. He remembered that in 1837, just after Mr. Ross
had constructed his first 4th lens, he (the President) had shown him
the Podura scale with dark-ground illumination, when Mr. Ross was
ereatly struck by the singular beauty of the view presented. By a
little alteration in the obliquity of the light the small spines varied
in colour, which led him (the President) to infer that they were
small circles upon larger ones. It is evident, however, that instead
of this there are two membranes with an elevation between them,
which causes the hollow cone below the spherules. The surface of
the scale is certainly corrugated, and he believed that smaller corru-
gations drawn by Dr. Pigott had led him to suppose that the surface
was covered with beads. He should be glad to find that Dr. Pigott
could confirm his own statements; in the meanwhile, however, in the
presence of so many different opinions, he could only repeat the
maxim, Quot homines tot sententic.

The meeting was adjourned until 8th December.

After the meeting was concluded Mr. McIntyre exhibited under
the microscope the well-known test-scales of Lepidocyrtus curvicollis
and Degeria domestica, and the following live specimens of the insect,
viz. Templetonia, Lepidocyrtus macrotoma, and Degeria Beckii.

Donations to the Library and Cabinet from October 13th to
November 10th, 1869 :—

From
Land and Water. Weekly ey RE LL crime Ba. 3562.
Scientific Opinion. Weekly .. .. .. «2 « «oF « Lditor.
Society of Arts Journal. Mae) oe), wet {oe | be. em gee ammo cree
Nature, “Weekly. 2.) 2.. en Ee MRS Nee 55,
The Student... Publisher.
Alcuni Cenni Sovra Studio dei Corpi Frangiati Delle ‘Rane
dei Professori G. B. Crivelli e Leopoldo Maggi .. .. Author.
Intorno Alla Produzione del Leptothrix nota dei Professori
G. B. Crivellie L. Maggi .... Author.
Sulla Produzione di Alcuni Organismi Inferiori in Presenza
dell’ Acido Fenico. Professori G. B. Crivelli e Leopoldo
i Author.

Mig eo? deco bcd acistany Mews Noted thee) cee Sek L wien, Boe
Sulla Produzione del Bacterium Termo Duj. e del Vibrio

Bacillus Duj. dei Professori G. B. Crivellie L. Magei .. Author.
Sulla Derivazione del Bacterium Termo Duj. e del Vibrio

Bacillus Duj. dai Granuli Vitellini dell’ ovo di Pollo

nota dei Professori G. B. Balsamo Crivelli e L. TREE. Author.

The Chemical News. 6 Nos. .. . W.T. Suffolk, Esq.
Quarterly Journal of Geological Society . sis vine Pew WOCTEROE

An Amici Reflecting eee A byt Cuthbert... .. Dr. Millar.

Four powers for the above .. een oe ee” eee sigan

An improved Double Nose-piece | ws Se RH Ree) set, aa! ee ea ee
Half-a-dozen Slides of Insects’ Eggs oat ee: |b) too! eid? | DG ARI ee rremernaee

eae W. RzEevzs,
Assist.-Secretary.

ee ee PROCEEDINGS OF SOCIETIES. 335

Oxtp CHANGE MicroscoPpicAL Socrety.*

Oct. 29th, Nov. 5th, and 12th. The President, Charles J. Leaf,
Esq., F.L.S., &c., in the chair.

Professor T. Rymer Jones continued his course of lectures on
“ Comparative Anatomy,” his lectures on these evenings being upon
the Crustaceans and Entomostracans.

November 19th.—In the unavoidable absence of the President,
F. H. Leaf, Esq., presided. There was an attendance of about sixty
members and visitors.

- Mr. C. J. Richardson made some extempore observations on the
Polyzoa, which were illustrated by the aid of diagrams and living
specimens of Plumatellu repens and Fredicella sultana.

Mr. H. Woodward, F.G.S. (of the British Museum), delivered a
lecture on “ Crabs, Lobsters, and Prawns.” The lecturer’s remarks
included Fossil and recent families of Crustaceans, and were illus-
trated by numerous and beautiful diagrams and specimens.

The cordial thanks. of the Society were awarded to Mr. C. J.
Richardson and to Mr. H. Woodward, F.G.S., at the conclusion of
their remarks.

The Secretary announced the following donations to the Society,
and thanks were passed to the respective donors :—

Donor.
PE WOMEVENSCS oi, 5. eee we we ts «|S Le President.
Collection of Sponges ae) Ys Be batty, can Le (ONE AC pe aoe Ops
Collection of Alpaca... nace MRL REINE, Burgesses
Two Slides of Marine Polyps” bine sominy wenmelinon Wey Camutiens. sl 19.

Journal of the Quekett Micro. Club si ea peeen Clo,

A unanimous vote of thanks to the Chairman terminated the pro-
ceedings.

* Report supplied by Mr. S. Helm, F.R.MLS.

Notr.—Reports of various Societies, though in type, are compelled through
want of space to stand over till January. _—Ep. M. M. J.

Monthly Mi ical
( 336 ) Rr ee: Dec. 1, 1369.

BIBLIOGRAPHY.

Etudes expérimentales sur la régénération des tissus cartilagineux
et osseux; par M. Peyraud. Paris. V. Masson.

Note sur un nouveau genre du Groupe des Zygnémacées ; par
M. Cornu. Paris. Martinet.

Beitrage zur Mikroskopischen Anatomie der acinédsen Drusen, von
Dr. Franz Boll. Berlin. Hirschwald.

Kurze Darstellung der Lehre Darwin’s ueber die Entstehung der
Arten der Organismen mit erlauterenden Bemerkungen, von Prof.
Dr. Jul Dub. Stuttgart. Schweizerbart.

Darwin und der Darwinismus, von Prof. Karl B. Heller. Wien.
Beck’sche Buchhandlung.

Das Mikroskop und seine Anwendung, von Herrn -H. Hager.
Berlin. Springer.

Hierstock und Ei. Hin Beitrag zur Anatomie und Entwicklungs-
geschicte der Sexual-organe, von Dr. Waldeyer. Leipzig. Engel-

mann.

Grundzuge der vergleichenden Anatomie, von Prof. Carl Gegen-
baur. Leipzig. Engelmann.

Ueber eigenthiimliche Zellen in der iris des Huhnes, von Herrn
Hiittenbrenner, Wien. Gerold’s Sohn.

Beitraige zur Kenntniss vom feineren Bau der Kleinhirnrinde, von
Herrn H. Obersteiner. Wien. Gerold’s Sohn.

Zur Histiologie der Vater-Pacini’schen Kérperchen, von P. Michel-
son. Kénigsberg. Hiibner.

Monthly ee |
Journal, Dec. 1, 1869.

Dod

INDEX TO VOLUME II.

A.

AcANTHOCYSTIS Viripis, 210.

Acaridee, the Development of. By M.
Van BeEneEDEN, 114.

Apvcock, Caas., M.R.C.S, on the New
Universal Dissecting Microscope, 1g

Alciope, the Development of. By Dr.
Bucuuo.z, 49.

American Association for the Advance-
ment of Science, 53.

Ameceba diffluens and Arcella vulgaris,
Effects of Induction-currents on. By
M. T. W. ENGELMAnNN, 112.

Anacharis alsinastrum, the Movement
of the Protoplasm in the Cells of. By
Professor SCHNETZLER, 271.

Anatomical Specimens, Brunetti’s Pro-
cess of Preparing, 51.

Anatomy of the Reproductive System.

' By Herr GussENHAUER, 327.

Animals, Histology of the Lower. By
Herr Fritz Ratzez, 210.

Arnpt, Dr. R., the Arrangement of the
Outer Nervous Layer “of the Cere-
brum, 271.

Ascidians, Crustacea Parasitic on. By
Herr BucHHo.z, 50.

Association, the British, 53.

Aulacodiscus oreganus, the Double Plate
of. By Mr. R. C. GREENLEAF, 326.

B.

Bacteria, the Origin of.
TEBNOW, 01.

Batuey, Mr. Cuas,, A Sea-deposit des-
titute of Foraminifera, 272.

Barxkas, T. P., F.G.S., on a Supposed
Mammalian Tooth from the Coal-
measures, 104.

Battledore Scales of Butterflies. By
Joun Watson, Esq., 73.
Bed-bug, the Anatomy of.
Professor Lannors, 209.
BENEDEN, VAN M., on the Development

of Acaridez, 114.

Recherches sur l’Embryogénie des
Crustacés, 208, 273.

BerKeEey, Rev. M. J., M.A., Observa-
tions on the Recent Investigations
into the Supposed Cholera Fungus,12.

VOL. II,

By Dr. Poto-

By Herr

Bessarabia, the Fossil Bryozoa of, 274.

Bibliography, 64, 120, 176, 224, 288,
336.

Birds and Mammals, the Central Ner-
vous System of. By Dr. Srrepa, 49.

Birds, the Anatomical Relations of the
Ciliary Muscles in. By Henry Law-
son, M.D., 204.

Blood, the Microzymee of the, 275.

Blood-corpuscle, the Structure of the
Human. By Professor Fresrr, 213.

Blood-stains, Detection by the Micro-
scope of Red and White Corpuscles

- in. By Dr. J. G. Ricuarvson, 147.

Borlasia, a New Hermaphrodite. By
M. A. F. Marron, 169.

Bourmans, A., on a New Process for
Photo-micrography, 51.

Brain, the Microscopical Structure of
the Convolutions of the. By Mr.
CiarkKE, 211.

, the Preservation of Sections of.
By Aurrep Sanpers, M.R.CS.,
326.

Branchiopoda, the Development of. By
Mr. E. S. Morse, 216.

BRoADBENT, Dr. W. D., on the Structure
of the Cerebral Hemispheres, 165.
Brown, Professor, on the Milk and
Blood of Animals with Foot and

Mouth Disease, 275.

Browninc, Joun, F.R.A.S., on the
Correlation of Microscopic Physiology
and Microscopic Physics, 15.

ona Simple Form of Micro-spectro-
scope, 65. /

Brownine’s Miniature Spectroscope,
116.

Brunettis Process for
Anatomical Specimens, 51.

Brunner’s Glands, the Structure of. By
Herr ANTON SCHLEMMER, 169.

Bryozoa, the Structure of. By Herr
SCHNEIDER, 49.

, Fossil, 51.

——, the Fossil of Bessarabia, 274.

Bucuyo.z, Herr, on Crustacea Parasitic
on Ascidians, 50.

—, Dr. on the Development of
Alciope, 49.

Butterflies, Battledore Scales of. By
Joun Warson, Esq., 73.

2A

Preparing

338

C.

Carboniferous Limestone, Report on
Mineral Veins and their Organic
Contents in. By Cuas. Moore,
F.G.S., 182.

Carpenter, Dr. W. B., on the Rhizo-
podal Fauna of the Deep Sea, 161.
Carrutuers, W., F.L.S., on the Struc-
ture of the Stems of the Arborescent
Lycopodiaceze of the Coal-measures,

177, 225.

Caryophyllaceze, Seeds of the, 54.

Cell, a Simple Form of. By Mr. W.
Bevan Lewis, 328.

Cells within Cells.
274.

Cerebellum, the Structure of the. By
Herr OBERSTEINER, 273.

Cerebral Hemispheres, the Structure
of. By Dr. W. D. Broapsent,
165.

Cerebrum, the Arrangement of the
Outer Nervous Layer of the. By Dr.
R. Arnpt, 271.

Chlorophyll of Plants, Spectroscopic
Researches on. By Dr. W. B. Hrra-
PATH, ERO. Lob:

Cheetopoda, the Development of the.
By Professor CLAPAREDE, 209.

Cholera Fungus, Observations on the
recent Investigation into. By the
Rev. M. J. Berxetery, M.A., 12.

CLAPAREDE, Professor, on the Develop-
ment of the Choetopoda, 209.

CuarkE, Mr., on the Microscopical
Structure of the Convolutions of the
Brain, 211.

Class Demonstrations,
graphy Applied to.
warD, U.S.A., 165.

CopsoLp, T. Spencer, M.D., Supplement

By Mr. Darwin,

Photo-micro-
By Col. Woop -

to the Introduction to the Study of |

Helminthology, 110.

Collecting-bottles, Mr. Moa1ntzn’s New
Strainer for, 328.

Collections, Prizes for, 170.

Coxtins’s Portable Microscope, 218.

Condensing Illuminator for Parallel
Rays. By Dr. Royston Picort,
169.

Coniferee, the Leaves of. By Mr. Tuxos.
Meruan, 169.

Country Fellows of the R.MLS., 218.

Crookes on the Micro-spectroscopic
Characters of Opals, 111.

Crustacea, the Embryogeny of. By M.
Epovarp VAN BENEDEN, 208, 273.
Crystalline Lens, the Development of

the, 273.
Cusirt, Cuas., F.R.M.S., on Floscularia
coronetta, a new Species, 133.

INDEX.

Monthly Microscopical
Journal, Dec. 1, 1869.

dD,

Darwin on Cells within Cells, 274.

Deep Sea, on the Rhizopodal Fauna of
the. By W. B. Carpenter, M.D.,161.

Definition, on High-power, with illus-
trative examples. By G. W. Royston
Pigott, M.A., 295.

Diatom Prism, and the True Form of
Diatom-Markings. By the Rev. J. B.
Reape, M.A., 5, 79.

Diatoms and Podura Scales, on the
Structure of. By F. H. Wenuam, 25.

Diatoms, Photographing, 280.

Dog-woods, the Microscopical Examina-
tion of. By Mr. J. R. Jackson, 172.

Dwicnt, Dr. Txos., Jun., on the Use of
Chloride of Gold in Microscopy, 45.

E.

Epwarps, M. Mitnn, on the Nervous
and Vascular Systems of Limulus,
aL

Ermer, Herr D. T., on the Structure of
the Mucous Villi, 271.

Embryology, Comparative.
Metscunixow, 50.

EncEeLMAnn, M. T. W., on the Effects of
Induction-currents on Amoeba dif-
fluens and Arcella vulgaris, 112.

Entomology, a Year-Book of American,
55.

Entomostraca, on Collecting and Mount-
ing. By J. G. Tarem, 269.

Entozoa: being a Supplement to the
‘Introduction to the Study of Hel-
minthology.’ By T. Spencer CoBBoLp,
M.D., 110.

Exogenous Stems from the Coal-mea-
sures, on the Structure of. By W. C.
WILLIAMSON, 66.

Expedition, Dr. Carpenter’s Deep-sea,
214.

Eye, the Histology of the. By Mr. J.
W. Hvtxg, 171, 227.

F.

Ferns, the Distribution of the Tracheal
Vessels in, 169.

Fieip’s, Mr. J. J., Ratio-micro-polari-
scope, 276, ©

FioceL, Herr J. H. L., on the Oval
Apparatus of Oxyuris, 210.

Floscularia coronetta, with Observations
on. By Cuas. Cusirt, F.R.MLS., 133.

Fly, the Rectal Papille of. By B. T.
Lowne, M.R.C.S., 1.

Foot and Mouth Disease, Microscopic
Investigation of Milk and Blood of
Animals with. By Professor Brown,
279.

By Prof.

Monthly Microscopical
Journal, Dec. 1, 1869.

Foraminifera, a’ Sca-deposit destitute of.
By Mr. Cuas. Battry, 272.

Fossil Bryozoa, 51.

Freer, Professor, on the Structure of
the Human Blood-corpuscle, 213.

Fungi, a Handbook of the British, 218.

G.

Gall-ducts, the Origin of.
OC. Stizs, 168.

GANIN, Herr, on the Development of
Insects, 172.

Generation, Experiments on Spontane-
ous. By Epwarp Parrirt, 253.

GiannvzzI, M., on the Structure of the
Pancreas, 52.

Gold, Chloride of, in Microscopy. By
Tuos. Dwieut, jun., M.D., 45.

Goucon, Dr. E., on the Tactile Cor-
puscles in the Parroquet’s Beak, 172.

GREENLEAF, Mr. R. C., on the Double
Plate of Aulacodiscus oreganus, 326.

By Dr. R.

H.

Hacen, Dr. H., My Experience in the
Use of various Microscopes, 321.

Herapatu, Dr. Birp, F.R.S., on Spec-
troscopic Researches on the Chloro-
phyll of Plants, 131.

Heterogeny, Jottings from the Note-
book of a Student of. By Mrrca.re
Jounson, M.R.CS., 99.

Histology, the French Academy’s Prizes
in, 53.

Hoee, Jaserz, F.L.S., on the Results of
Spectrnm Anaiysis, 121.

Holtenia: a Genus of Vitreous Sponges,
By Wyvi.te Tomson, LL.D., 107.
Hoorrr, J. Howarp, on a New Manipu-

lator, 218.

- Hupson, C. T., LL.D., Notes on Hyda-
tina Senta, 22.

Huike, Mr. J. W., the Histology of the
Eye, 177, 227.

Hyarr, Mr. Aupyrus, on the Homo-
logies of the Polyzoa, 327.

Hydatina Senta, Notes on. By C. T.
Hupson, LL.D., 22.

it;

Illumination, Dark-ground and Oblique,
a suggested Plan for, 170.

for Verifying the Structure of

Diatoms, &c., Some further Remarks

on. By F. H. Wennam, 158.

INDEX,

ood

Immersion Lenses, Mr. Ross’s New,
217.

—— Lenses and the New Nineteen-
band Test-plate of Nobert, further
Remarks on. By Lieut.-Col. J. J.
Woopwarb, U.S. Army, 289.

Objectives, 171.

Infant, the Histology of the Lips of the.
By Herr Kuen, 52.

Infusions, the Development of Organ-
isms in Organic. By OC. S. Wakz,
F.A.S.L., 306.

Injecting Specimens, Apparatus for.
By Herr D. Toupt, 48.

— Specimens for Microscopic Pur-
poses. By Mr. T. SHarps, 53.

Insects, the Development of. By Herr
GANIN, 272.

, Preserving, 116,

Invertebrata, the Histology of the
Muscular Tissues of. By V. G.
ScHWALBE, 49.

J.

JOHNSON Mercatre, M.R.CS., Jottings
from the Note-book of a Student of
Heterogeny, 99.

K.

Kern, Herr, on the Histology of the
Lips of the Infant, 51.

Krause, Professor, on Our Knowledge
of the Retina, 172.

ibe

Lanpors, Herr, Professor, on the Ana-
tomy of the Bed-bug, 209.

Lawson, Henry, M:D., on the Anato-
mical Relations of the Ciliary Muscles
in Birds: 1st. The Green-breasted
Pheasant, 204.

Lenses, Mr. Ross’s New Immersion,
ilies ;

Lepidoptera : Further Remarks on the
Plumules or Battledore Scales of some
of the. By JoHN Watson, Hsq.
314,

Lewis, Mr. W. Bevan, on a Simple
Form of Cell, 328.

Life, the Origin of, 328.

Limulus, the Nervous and Vascular
Systems of. M. A. Minne Epwarps,
111.

Logwood, Polarizing Crystals from,

280,
De MD

340 INDEX.

LownE, B. T., on the Rectal Papillee
of the Fly, 1.

Lurrssen, Herr C. W., on the Pollen
Grains of Onagracese Cucurbitacese
and Corylacee, 210.

Lycopodiaceze of the Coal-measures,
on the Structure of the Stems of.
By B. W. Carrutuers, F.L.S., 177,
225.

Lymneus: the Anatomy and Develop-
ment of the Reproductive Apparatus
of, 271.

M.

McNas, Dr. W. R., on the Staining of
Microscopical Preparations, 155.

Mappox, Dr. R. L., on Mucor Mucedo,
140.

Manipulator, a New. By J. H. Hooper,
218.

Marion, M. A. F., on a New Herma-
phroditie Borlasia, 169.

MarsnHa.t, Wi.11AM P., on the Univer-
sal Mounting and Dissecting Micro-
scope, 335.

Masters, M. T., M.D., on Vegetable
Teratology, 47.

Merenan, Mr. Tuos., on the Leaves of
Conifera, 169.

Merrscunikow, Professor, on Compara-
tive Embryology, 50.

Meteorites under the Microscope, 217.

Micro-photographs, 171.

Microscope, Selenite Plates for the,
56.

——,, the, what it has done, 55.

——., the New Universal Dissecting. By
Cuas. Apcock, M.R.C.S., 171.

, the Universal Mounting and Dis-
secting. By W. P. MarsHALt, 335.

——., how to work with the, 217.

——,a New Dissecting, Mr. C. CoLiins’s,
217.

——, Cotiins’s Portable, 218.

——., Rain-water under the, 274.

— , the, Attacked and Defended, 280.

——, My Experience in the Use of vari-
ous. By Dr. H. Hacen, 321.

Microscopic Perfection, Messrs. Cas-
SELL’S Estimate of, 170.

— Physiology and Microscopic
Physics, on the Correlation of. By
JoHN Brownine, 15.

Research, on Methods of. By
Herr S. Stricker, 84.

Microscopical Preparations, on the Stain-
ing of. By Dr. W. R. McNas, 155,

Slides, 55.

see in the Peabody Academy,

Monthly Microscopical
Journal, Dec. 1, 1869.

Micro-spectroscopy, on 4 Simple Form
of. By JoHn BRowninaG, 65.

Micro-spectroscopy, Results of Spectrum
Analysis. By Jasez Hoee, F.LS.,
2a

Microzyme of the Blood, 275.

Milk of Diseased Cows under the Micro-
scope, 280.

Moore, Cuas., F.G.8., Report on Mineral
Veins and their Organic Contents in
Carboniferous Limestone, 182.

Morss, Mr. E. 8., on the Development
of Brachiopoda, 216.

Moths, Plumules of, 218.

Mucor Mucedo, Observations on. By
Dr. Mapvox, 140.

Mulberry, the Latex Fluid of, 172.

N.

Nerve, the Structure of the Axis-cylinder
of, 50.

Nerve-tissue, the Structure of, 271.

Nobert’s Lines, Photographs of, 214.

O.

OBERSTEINER, Herr, on the Structure
of the Cerebellum, 273.

Object-glasses for the Microscope, on
the Construction of. By F, H.
WENHAM, 93.

Objectives, Immersion, 171.

New, Good, and Cheap Foreign,
328.

Obsidian, Microscopic Examination of.
By Mr. W. C. Roserts, F.CS.,
214.

Onagraceze Cucurbitaceze and Cory-
laceze, the Pollen Grains of. By
Herr C. W. Lurrssen, 210.

Opals, the Micro-spectroscopic Charac-
ters of. By Mr. Crooxgs, 111.

Orthoptera, Structure of the Wing of
the, 50.

Oxyuris, the Oval Apparatus of. By
Herr J. H. L. FLocet, 210.

P.

Pancreas, the Structure of the. By M.
GIANNUZZI, 52.

Parrirt, Epwarp, Experiments on
Spontaneous Generation, 253.

Parroquet’s Beak, Tactile Corpuscles
in. By Dr. KE. Goveon, 172.

Peabody Academy, Microscopy in tke,
shy

Monthly Microscopical
Journal, Dec. 1, 1869.

Pericheta, Anatomy of, 50.

Priiicer, Herr, on the Terminations of
the Nerves in the Pancreatic and
Salivary Glands, 48.

Phallusia, Organs? of Generation in.
By M. Paut Srepanorr, 50.

Pharynx, the Adenoid Tissue of the
Nasal Part of the, 50.

, the Mucus of the Arch of the, 50.

Photo-micrography, a New Process for.
By M. Bourmanys, 51.

Pigorr, Dr. Royston, on a Parallel-rays
Condensing Illuminator, 169.

, Dr. G. W. Royston, M.A., on
High-power Definition, with Illustra-
tive Examples, 295.

Pike, Observations on the Development
of the Ovum of. By EH. B. Truman,
M.D., 185.

Plants, the Sleep of. By M. Cu. Royer,
51

Podura Scales and Diatoms, on the
Structure of. By F. H. Wrennam, 25.
Po.oresnow, Dr., on the Origin of
Bacteria, 51.
_Polyzoa, the Homologies of the. By
Mr. Aupurevs Hyatt, 327.
Pond Life Photographed, 54.
Preserving Insects, 116.
Prize Essay of the Boston Natural His-
tory Society, 116.
Prizes offered by the Belfast Natural-
ist’s Field Club, 170.
PROCEEDINGS OF SOCIETIES :—
Birmingham Natural History and
Microscopical Society, 118.
Brighton and Sussex Natural History
Society, 63, 117, 174, 221, 287.
Bristol Microscopical Society, 63,
288.
Illinois State Microscopical Society,

Liverpool Microscopical Society, 62,
119, 222.
Maidstone and Mid-Kent Natural
History Society, 63.
Manchester Circulating Microscopical
Society, 62, 174.
~— Lower Mosley Street Natural
History Society, 174.
Montreal Microscopical Club, 279.
Old Change Microscopical Society,
286, 334.
Oldham Microscopical Society, 173,
287.
Quekett Club, 61, 117, 220, 285.
Royal Microscopical Society, 56, 220,
281, 330.
Professorship, the Hunterian, 53.
Protoplasm, Life Force, and Matter,
217.
—— Dr. L. BEaLzE on, 328.

INDEX.

o41

R.

Rain-water under the Microscope, 274.

Ravze., Herr Frirz, on the Histology
of the Lower Animals, 210.

Ratio-micro-polariscope, the. By Mr.
J.J. FIELD, 276.

READE, the Rev. J. B., on the Diatom
Prism, and the True Form of Diatom
Markings, 5, 79.

Recherches sur l’Embryogénie des Cru-
stacés. Par EpouARD VAN BENEDEN,
1869, 208.

Reinke, Herr J., on the Reproductive
System of Saprolegnia monoica, 48.
Reproductive System, the Anatomy of

the, 327.

Retina, our Knowledge of. By Professor
Krause, 172.

Ricuarpson, Dr. J.G.,on the Detection
of Red and White Corpuscles in
Blood-stains, 147.

Roserts, Mr. W. C. Microscopic Ex-
amination of Obsidian, 214.

8.

Salivary Glands, Terminations of the
Nerves in. By Herr Prtiicnr, 48.
SanpgErs, ALFRED, M.R.C.S., on the
Preservation of Sections of Brain and

Spinal Cord, 326.

Saprolegnia monoica, the Reproductive
System of. By Herr J. Rernxg, 48.
SavussurE, M. de, on the Structure of

the Wing of the Orthoptera, 50.
ScuLEmMMER, Herr Anton, on the Struc-
ture of Brunner’s Glands, 169.
SCHNEIER, Herr, on the Structure of
the Bryozoa, 49.
ScHwa.se, V. G., on the Muscular Tis-
sues of the Invertebrata, 49.
Seeds of the Caryophyllacee, 54.
Selenite Plates for the Microscope, 56.
SHarp, Mr. T., on Injecting Specimens
for Microscopic Purposes, 54.
Siphonophora, the Reproduction of, 210,
Smiru, Dr. Davin, on the Structure of the
Adult Human Vitrecus Humour, 30.
Snake-bird, a Peculiar Minute Thread-
worm infesting the Brain of. By
Dr. J. Wyman, 215.
Spectroscope, Brownine’s Miniature,

Spinal Cord, Regeneration of the, 273.

, the Preservation of*Sections of,
By Aurrep Sanpers, M.R.CS., 326.

Stage, Mr. SrepHeNson’s New Safety,
328.

STEPHENSON, Mr., on a New Safety Stage
for the Microscope, 328.

342 INDEX.

STEPANOFF, M. Pavt, on the Organs of
Generation in Phallusia, 50.

StTiepA, Dr., on the Central Nervous
System of Birds and Mammals, 49.
Stines, Dr. R. C., on the Origin of

Gall-ducts, 168.
Srricker’s Histology, a Translation
of, 279,

.

Teenia cucumerina, 271.

Tarem, J. G., on Collecting and Mount-
ing the Entomostraca, 269.

Theonella, or Dactylocalyx, 54.

TxHomson, WyvitLE, LL.D., on Hol-
tenia: a Genus of Vitreous Sponges,
107.

TotpT, Herr D., on an Apparatus for
Injecting Specimens, 48.

Tooth, Supposed Mammalian, from the
Coal-measures. By T. P. Barxas,
F.GS., 104.

Tricot, M. A., on the Distribution of
the Tracheal Vessels in Ferns, 169.
Trichina Spiralis: a Prize Essay, 116-
Truman, EK. B., M.D., Observations on
the Development of the Ovum of the

Pike, 185.

U.

Ustilaginese, the Natural History and
Development of the, 211.

V.

VaILLANTt, M. Leon, on the Anatomy of
Pericheeta, 50.

Vegetable Teratology. By Maxwetu
T. Mastrrs, M.D., 47.

Monthly Microscopical
Journal, Dec. 1, 1869.

Villi, the Structure of the Mucous. By
Herr Dr. Tu. Ermer, 271.

Vitreous Humour, Structure of the
Adult Human. By Davin Smirtu,
M.D., 30.

W.

Wakz, C.S8., F.A.S.L., on the Develop-
ment of Organisms in Organic Infu-
sions, 306.

Watson, Joun, Esq., on the Battledore
Scales of Butterflies, 73.

, Further Remarks on the Plumules
or Battledore Scales of some of the
Lepidoptera, 314.

WenuaM, F. H., Some further Remarks
on an Illumination for Verifying
the Structure of Diatoms and other
Minute Objects, 158.

on the Structure of Diatoms and

Podura Scales, 25.

on the Construction of Object-
glasses for the Microscope, 93.

Wiuiiamson, W. C., F.R.S., on the
Structure and Affinities of some Exo-
genous Stems from the Coal-measures,
66. ;

Woopwarp, Col., on Photo-micrography
applied to Class Demonstration,
165.

—, Further Remarks on the New
Nineteen-band Test-plate of Nopurt,
and on Immersion Lenses, 289.

Worms and Crustacea, Intermediate
Forms between, 210.

Wyman, Dr. J., on a peculiar Minute
Thread-worm infesting the Brain of
the Snake-bird (Plotus anhinga),
215.

END OF VOLUME II.

LONDON: PRINTED BY W. CLOWES AND SONS, STAMFORD STREET AND CHARING CROSS.

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