qua g^oh

C, (p Jo}

f

Al6X.

filmu-ii of fbc Ifluscum

or

COMPARATIVE ZOOLOGY,

AT HARVARD COLIECE, CAMBRIDGE, MASS.
Jfoun^ieU fti) prfbntc subscription, fu 1861.

Deposited by ALEX. AGASSIZ.

No. y6~py.

TRANSACTIONS

OF THE

ROYAL

MICROSCOPICAL SOCIETY.

NEW SERIES.

VOLUME XV.

m

LONDON:

JOHN CHURCHILL AND SONS, NEW BURLINGTON STREET.

1867.

TRANSACTIONS OF THE ROYAL MICROSCOPICAL
SOCIETY OF LONDON.

Description of a Diaphragm Eye-piece for the Micro-
scope. By Henry J. Slack, F.G.S., Hon. Sec. Mic. Soc.

(Read October 10th, 1866.)

In viewing small objects by transmitted light, it frequently
happens that distinct vision is impaired, and the eye inju-
riously affected by the large size of the surrounding luminous
field. If we may compare the objects to an engraving, and
the rest of the luminous field to a white margin, we shall
find that different objects require a different portion of mar-
gin for their most pleasant and efficient display.

With a given intensity of illuminating power, it is evident
that the quantity of light affecting the eye will depend upon
the size of the space from which the light proceeds, and it
will be frequently found that the whole aperture of an eye-
piece admits far too much light when the intensity is nicely
proportioned to the requirements of the object. It is there-
fore desirable to have a ready means of cutting off the super-
fluous light by reducing the size of the luminous field, and,
as objects vary, not only in size, but in their relative propor-
tions of length and breadth, it is further desirable that the
field should be susceptible of corresponding changes.

Having these objects in view, the writer requested Mr.
Ross to adjust four moveable shutters, so that an A eye-piece
might be susceptible of all the changes in the form and size
of its field that different objects would require. This has
been accomplished in the eye-piece now shown to the society.
The new diaphragm stops are placed immediately over the
ordinary round stop of the A eye-piece, and they are worked
by four milled heads conveniently situated on the flange of
the eye-piece, and slightly projecting beyond it. Each of
vol. xv. a

2 Slack, on a Diaphragm Eye-piece for the Microscope.

these milled heads moves one shutter, which is capable of
closing half the field. By combining the movements of the
four shutters in various ways, it is easy to form a series of
symmetrical apertures bounded by straight lines, and of any
dimensions required. Unsymmetrical apertures can also be
formed, but they are usually very disagreeable to the eye,
and ought therefore to be avoided.

Astronomers have long been acquainted with the advantage
of restricting their field when looking at luminous objects of
lerge size, and the solar eye-piece of Mr. Dawes is a contri-
vance having this end view ; but so far as the writer is aware,
microscopists have not been in possession of any analogous
instrument.

The only objection to the general application of this
diaphragm stop to A eye-pieces, in the form now shown, is
that it slightly diminishes the full size of the field. This
arises from the writer having required that the shutters should
meet when drawn out to their full extent. To accomplish
this the shutters are rather broader than the ordinary stop.
If kept within the dimensions of that stop they would pro-
bably do all that is required, as experiment shows that the eye
is incommoded when the field is very small.

The diaphragm stop is most needed in the examination of
small objects sufficiently opaque to require a very intense
light for their display by transparent illumination ; but other
objects, such as diatoms and butterfly scales, are improved in
appearance, and have their markings made more striking
when the extent of the luminous margin surrounding them is
nicely adjusted to their special requirements.

The diaphragm stop may also be used as an indicator, as
it affords a ready means of isolating one out of many objects
that may be on a slide.

The writer believes that it will be found of much use in
protecting the eyes of microscopists, which are more liable to
injury from excess of light than from any other cause (bad
glasses excepted) incidental to their pursuits.

3

On a Double Hemispherical Condenser for the Micro-
scope. By the Key. J. B. Reade, F.R.S.

The hemispherical condenser, consisting of a single lens
with suitable diaphragms, was described to the Society in
May, 1861 ; and at the Exhibition in 1862 it received
“ honorable mention” by the appointed jury. This con-
denser was proposed as a cheap and not inefficient substitute
for more expensive apparatus, inasmuch as it enabled my
■^-inch object-glass to bring out with great distinctness the
markings on Pleurosigma angulatum and other similar tests.
This fact was proved by ocular demonstration to Mr. Boss,
whose skill had overcome the optical difficulties in producing
a large angle of aperture ; but my assertion of its power was
at first received with a smile of doubt.

The single hemisphere has only a small angle of illumina-
tion when the pencils converge from near the margin of the
lens to the object. Hence the value of its application to
deep powers was questioned by many, though, so far as my
own experience goes, the -|hh an^ Tyth are not beyond the
scope of its illumination. Still, something like tact may be
required — to use the language of objectors unskilled in its
manipulation — in order to put the single lens through all its
paces with all the powers. That the work can be done, but
done with difficulty, is, perhaps, somewhat less than the merit
which an inventor aims at, for, like poetry of a certain kind,
if the sense does not stare you in the face no one cares for it.

The felt want, then, is greater obliquity of the illuminating
pencil. With the single “ kettledrum,” the angle of illumi-
nation is rather less than 90°, and we all allow that this is
too small for the easy exhibition of the more difficult tests.
In the coarser lined objects the shadows are easily obtained
when the pencils of illumination have a comparatively small
angle ; but where the lines and markings are extremely thin
the angle must be nearly doubled, that the shadows may be
well defined and sufficiently intense.

I propose to obtain this greater obliquity by placing a
smaller hemisphere upon the larger one, and then the two
kettledrums, turned to fifths, may be made to play ujion any
scale. For practical purposes it is near enough the mark to
say that one lens, when placed upon another, adds its own
obliquity to the obliquity of the rays which fall upon it.
Neglecting, therefore, the smaller effects due to thickness and
density, it is certain, as a matter of fact, and proved by

4 Reade, on a Double Hemispherical Condenser.

measurement, that the illuminating pencils, after passing
through the two hemispheres, may be made to fall upon the
test objects at an angle of more than 150°, and thus produce
illumination on a dark field even with the -fl^th. This
obliquity, no doubt, increases the facility of dealing with
such close fine lines as those of the Amician test and the
Macrum. To check the latter has been described as “ a most
blinding and heart-rending and brain-softening test but
by using the double hemisphere, with the -y^th and C eye-
piece, the lines and dots may be counted with ease. It is also
not very difficult to make the whole battery of powers, from
the TVth to the -^-inch, available for the exposition of these
tests. A ^-inch of exquisite workmanship, now in my pos-
session, readily checks the Rhomboides, and a 4-th checks
both this test and the Macrum. These powers were presented
to me by my friend Mr. Wray, a Fellow of the Astronomical
Society, who has devoted many years to the difficult task of
annihilating the secondary spectrum in telescopic object-
glasses of large dimensions, and I have witnessed his success
with the highest gratification.

The want of achromatism in the double kettledrum is not
injurious ; on the contrary, the dispersion is beneficial rather
than otherwise when the deep powers are used. With these
the illumination is virtually monochromatic, and we may use
at pleasure the red, yellow, or blue ray, by slightly altering
the distance of the condenser. The blue ray, being the most
refracted, and therefore falling on the test lines with greater
obliquity, is decidedly the most effective on N. rhomboides.
The pure light of a bright white cloud reflected from the
plain mirror shows this very clearly. Webster’s condenser,
somewhat similar to mine, and consisting of two lenses
partially achromatized, is, in its present state, not more
effective than my single hemisphere. Mr. Highley, who
makes them, is now enlarging the angle of aperture, and thus
extending the application of the condenser.

The diaphragm-cap, properly constructed for one, two, or
three apertures, as in the case of the single hemisphere, may
be removed to the top of the second hemisphere, unless the
fineness of the lines under examination require the condenser
to be very close to the object. In this case a diaphragm of
tin-foil or of thin brass properly pierced may be placed
between the two hemispheres ; tin-foil has an advantage in
its very easy management. By looking down the body of the
microscope, when the eye-piece is removed, and examining
the dimensions of the discs of light, it is seen, at a glance,
whether one or other of the apertures require to be more or

Reade, on a Double Hemispherical Condenser. 5

less deeply cut. In the one case the little lappet of tin-foil
can be so doubled as to shorten the aperture, and in the other
it may he cut deeper and thrown further back. To obtain
these very slight but not slightly important variations, and
in a moment, is an advantage which minute observers will
readily recognise. It corresponds, in fact, to the gentle
strengthening or diminishing the gas-lights when the pair of
achromatic prisms is dexterously arranged by our friend Mr.
Tomkins, in order to give to rectangular lines the force of
illumination indicated by their thickness. Mr. Tomkins, to
take the Rhomboides as an example, after placing it perpen-
dicularly as to the major axis of the stage, proceeds to bring
out the transverse lines with the one prism, and then, shut-
ting off its light, acts on the longitudinal lines with the other.
The same admirable method of working may be adopted in
the case of the kettledrums by placing a bull’s-eye condenser
in front of the lamp. By a little alteration in the position
and height of this lens, the upper aperture, or that at right
angles to it, may be easily and separately used for the inde-
pendent exhibition of the transverse or longitudinal lines ;
the two pencils of light are then worked together, as through
the two prisms, for the final resolution of the valve.

In my own condenser a slit has been made in the brass-
work between the lenses for the insertion of the thin brass
diaphragms without the removal of the condenser, an arrange-
ment with which the Waterhouse diaphragms in photographic
combinations has made us familiar. With respect to these
diaphragms, I have made a new arrangement which gives
immediate and ready command over the length of the V
apertures, and therefore over the power of the illuminating
pencil for rectilineal tests. The method is this — on the sur-
face of the lower hemisphere place a circular diaphragm,
having apertures at right angles to each other, and extending
from the circumference to within a quarter of an inch from
the centre. On another circular diaphragm of the same size
draw diameters at right angles to each other, also draw lines
from the extremity of one diameter to the two extremities of
the other, and with a pair of scissors cut off the two lunes,
thus forming a right angle upon a semicircle. This rectan-
gular diaphragm is placed in the slit of the tube between the
condensers, so that the vertex of the right angle divides the
space between the two long Y apertures of the lower dia-
phragm. When pushed home it nearly shuts up the apertures
of the fixed diaphragm ; but by gently drawing it out, and
moving it a little sideways, if necessary, we can obtain with
the utmost nicety just that length of either aperture which

6 Reade, on a Double Hemispherical Condenser.

the test lines under examination require. It is absolutely
necessary to have this entire command over the length of the
apertures and the strength of the illuminating rays, and
this is one method, among others, which might suggest them-
selves to different observers, for securing this control. Two
narrow strips of brass having small V apertures may also be
conveniently used for the independent regulation of the two
lower and larger apertures, over which they should be moved
by a fine adjustment. The two hemispheres themselves
are, as it were, the mere raw material ; the secret of success
lies in the proper management of the condensed and conver-
gent pencils. In the diaphragm-cap the apertures are always
of one and the same size, and hence arises the only practical
difficulty in using it for the most delicate tests. By the present
arrangement the precise amount of light from either aperture
is obtained at once.

As cheapness is the order of the day, I may state that the
cost of the material for these diaphragms is “ three a penny.”
I cut the apertures with a pair of scissors, and after filing the
edges, when necessary, I blacken them with oxide of copper.
A few crystals of sulphate of copper must be dissolved to
saturation in two measures of strong nitric acid and one
measure of water. The diaphragm, raised to a temperature
of about 300° over a spirit lamp, is dipped in the solution
and immediately dried over the flame. On rubbing the
frost-like surface with a small brush a clean and permanent
black stain remains.

No light can fall upon the upper hemisphere but that
which passes through the apertures of the diaphragm on the
lower ; and as the apertures are generally about -jAths of an
inch deep, while the diameter of the lens itself is one inch
and three quarters, it is evident that the outer portion of the
hemisphere is alone called into use. There is, however, a
limiting circle, beyond which parallel rays of light are not
transmitted to the upper hemisphere. It may be an improve-
ment to bring this portion into play, and Mr. Ross is con-
structing a condenser of three lenses, in which every ray that
falls upon the first lens will be available for illuminating the
object.

What I have aimed at in the double kettledrum is a dis-
tinct and well-defined pencil of light, falling at right angles
on the lines of the object, and at the necessary obliquity for
resolution and definition ; and I trust that my experiments
will not be considered fruitless. I have often used the hemi-
spherical combination with much pleasure and satisfaction,
and, at the request of the Council, I now place R before this
Royal Society.

Charter and Bye-Laws of the Boyal Microscopical Society,

Objects of the Society. — The Boyal Microscopical Society
was founded in 1839, and incorporated by Boyal Charter,
1866, for the promotion and diffusion of improvements in
the optical and mechanical construction, and in the mode of
application, of the Microscope : —

For the communication and discussion of observations and
discoveries tending to such improvements, or relating to
subjects of Microscopical observation : —

For the exhibition of new or interesting Microscopical
objects and preparations, and for the formation of an arranged
collection of such objects : —

For affording the opportunity and means of submitting
difficult and obscure Microscopical phenomena to the test of
instruments of different powers and constructions : —

For the establishment of a Library of standard Micro-
graphical Works.

Royal Charter of Incorporation to the Microscopical Society

of London.

Victoria, by the grace of God, of the United Kingdom of
Great Britain and Ireland, Queen, Defender of the Faith,

To ALL TO WHOM THESE PRESENTS SHALL COME GREETING :

Whereas James Scott Bowerbank, Doctor of Laws, Fellow
of the Boyal Society; Bev. Joseph Bancroft Beade, Master
of Arts, Fellow of the Boyal Society; Nathaniel Bagshaw
Ward, Fellow of the Boyal Society; and others of our loving
subjects, did, in the year 1839, establish a Society by the
name of “ The Microscopical Society of London,” for the
advancement of Microscopical Science :

And whereas it has been represented to us that the same
Society has, since its establishment, sedulously pursued such
its proposed object, by the researches of its members, and the
collection and discussion of observations, and by the publica-
tion of its transactions from time to time, which have con-
tributed to the progress of Microscopical knowledge :

And whereas distinguished individuals in foreign coun-
tries, as well as British subjects, have availed themselves of
the facilities offered by the same Society for communicating
important discoveries, greatly extending Microscopical know-
ledge ; and the great and general interest now felt in those
branches of Science, whereof the Microscope is an important

8

Charter of the Royal Microscopical Society.

instrument of investigation, has been greatly promoted and
fostered by this Society :

And whereas the same Society has, in aid of its objects,
acquired a considerable and important Library of Scientific
Works, a large collection of Microscopic objects, and several
valuable Microscopes, to which frSsh accessions are con-
stantly being made; and the said Society has hitherto been
supported by donations and annual and other subscriptions
and contributions to its funds, and has therefrom purchased
and is possessed of a considerable amount of stock in the
public funds :

And whereas, in order to secure the property of the said
Society, to extend its operations, and to give it a more per-
manent establishment among the scientific institutions of our
kingdom, we have been besought to grant to James Glaisher,
Fellow of the Royal Society, the present President of the
said Society, and to those who now are or shall hereafter
become members of the said Society, our Royal Charter of
Incorporation for the purposes aforesaid :

Now know ye that We, being desirous of encouraging a
design so laudable and salutary, of our especial grace, certain
knowledge, and mere motion, have willed, granted, and de-
clared, and do by these presents, for us, our heirs and suc-
cessors, will, grant, and declare, that the said J ames Glaisher,
and such other of our loving subjects as now are members
of the said Society, or shall from time to time be elected
Fellows thereof, according to such regulations or bye-laws as
shall be hereafter framed or enacted, and their successors,
shall for ever hereafter be by virtue of these presents one
body politic and corporate, by the name of “ The Micro-
scopical Society of London and for the purposes aforesaid,
and by the name aforesaid, shall have perpetual succession
and a common seal, with full power and authority to alter,
vary, break, and renew the same at their discretion, and by
the same name to sue and be sued, implead and be impleaded,
answer and be answered, unto and in every court of us, our
heirs and successors, and be for ever able and capable in the
law to purchase, receive, possess, hold and enjoy, to them
and their successors, any goods and chattels whatsoever, and
also to be able and capable in the law (notwithstanding the
Statute of Mortmain) to take, purchase, hold, and enjoy to
them and their successors a hall or house, and any such
messuages, lands, tenements, or hereditaments whatsoever as
may be necessary or expedient for carrying out the purposes
of the Society, the yearly value of which, including the site
of the said hall or house, shall not exceed in the whole the

Charter of the Royal Microscopical Society. 9

sum of <=£] 000, computing the same respectively at the time
of the purchase or acquisition thereof, and to act in all the
concerns of the said body politic and corporate as effectually,
to all intents and purposes, as any other of our liege subjects,
or any other body politic or corporate in our said kingdom,
not being under any disability, might do in their respective
concerns.

And we do hereby grant our special licence and authority
unto all and every person and persons, bodies politic and
corporate (otherwise competent), to grant, sell, alien, and
convey in mortmain unto and to the use of the said body
politic and corporate and their successors any messuages,
lands, tenements, or hereditaments not exceeding such annual
value as aforesaid.

And our will and pleasure is, and we further grant and
declare, that there shall be a General Meeting or General
Meetings of the Fellows of the said Society to be held from
time to time as hereinafter mentioned, and that there shall
be a Council to direct and manage the concerns of the said
body politic and corporate, and that the General Meetings
and the Council shall have the entire direction and manage-
ment of the same in the manner and subject to the regula-
tions hereinafter mentioned.

And we do hereby also will, grant, and declare that there
shall be a President, Vice-Presidents, a Treasurer, and Secre-
taries of the said body politic and corporate, and that the
Council shall consist of the President, Vice-Presidents, Trea-
surer, Secretaries, and not more than twelve nor less than
eight other Fellows of the said Society.

And we do hereby further will and declare that the said
James Glaisher shall be the first President of the said body
politic and corporate, and the other persons now being the
Vice-Presidents, Treasurer, Secretaries, and Members of
the Council shall be first Members of the Council, and shall
continue such until the election of officers shall be made in
pursuance of these presents.

And we do hereby further will and declare that it shall be
lawful for the Fellows of the said body politic and corporate
hereby established to hold a General Meeting once in the year
or oftener, for the purposes hereinafter mentioned; namely,
that the President, Vice-Presidents, the Treasurer, the Secre-
taries, and other Members of the Council, shall be chosen at
such General Meeting, and that the General Meetings shall
from time to time make and establish such bye-laws, and
vary and alter or revoke the same, as they shall deem to be
useful and necessary for the regulation of the said body politic

vol. xv. b

10 Charter of the Royal Microscopical Society.

and corporate, for the admission of Fellows and of Honorary
and Foreign Members, and for the fixing the number of the
Vice-Presidents and Officers, and for the management of the
proceedings, and the estates, goods, and business of the saicL
body politic and corporate, so that such bye-laws be not
repugnant to these presents, or to the laws and statutes of this
our realm ; and shall and may also enter into any resolution
and make any regulation respecting the affairs of the said
body politic and corporate that may be necessary and proper :

And we do further will and declare that the General
Meetings shall take place at such time as may be fixed by the
said Council, and that the present regulations of the said
Society, so far as they are not inconsistent with these pre-
sents, shall continue in force until the same shall be altered
by a General Meeting.

And we further will, grant, and declare that the Council
shall have the sole management of the income and funds of
the said body politic and corporate, and the appointment of
librarian, curator, and such other officers, attendants, and
servants as the Council shall think necessary or useful, as also
the entire management and superintendence of all the other
affairs of the said Society, and shall and may, but not incon-
sistently with or contrary to the provisions of this our Charter,
or any existing bye-law, or the laws and statutes of this our
realm, do all such acts and deeds as shall appear to them
necessary for carrying into effect the objects and views of the
said body politic and corporate.

Provided always, and we do will and declare, that the
Council shall, from time to time, render to a General Meeting
a full account of their proceedings, and that every Fellow of
the Society may at all reasonable times, to be fixed by the
said Council, see and examine the accounts of the receipts
and payments of the said body politic and corporate.

And we further will, grant, and declare that the whole pro-
perty of the said body politic and corporate shall be vested,
and we do hereby vest the same, solely and absolutely in the
Fellows thereof ; and that they shall have full power and
authority to sell, alienate, charge, and otherwise dispose of
the same as they shall think proper : but that no sale, mort-
gage, incumbrance, or other disposition of any messuages,
lands, tenements, or hereditaments belonging to the said body
politic and corporate shall be made except with the appro-
bation and concurrence of a General Meeting.

And we lastly declare it to be our Royal will and plea-
sure that no resolution or bye-law shall, on any account or
pretence whatsoever, be made by the said body politic and

11

Charter of the Royal Microscopical Society.

corporate, in opposition to the general scope, true intent, and
meaning of this our Charter, or the Laws or Statutes of our
Realm : And that if any such rule or bye-law shall he made,
the same shall be absolutely null and void to all intents,
effects, constructions, and purposes whatsoever.

In witness whereof we have caused these our Letters
to be made Patent.

Witness ourself, at our Palace at Westminster,
this twenty- eighth day of August, in the thirtieth
year of our reign.

By Her Majesty’s Command.

CARDEW.

TRANSACTIONS OF THE ROYAL MICROSCOPICAL
SOCIETY OF LONDON.

On two new Species of the Genus (Ecistes, Class
Rotifera. By Henry Davis, F.R.M.S.

(Read December 12th, 1866.)

The hitherto undescribed species of tuhiculous Rotifera
which I have to introduce, furnish further proof — if such be
needed — that the generally accepted classification of these
animals is unsatisfactory in the extreme. In the present
instance there would almost seem to be a special arrange-
ment for the purpose of excluding some interesting creatures
— possessing in every sense a “local habitation,” hut no
“ name ” — from enjoying the advantages of acknowledged
relationship with their greater and more famous compeers.

Mr. Gosse has recently proposed to subdivide the class in
a manner not only more natural and less arbitrary than that
complained of, hut having the further advantage, in its com-
prehensiveness, of admitting as well-defined species the new
rotifers in which I am particularly interested. He proposes
to make a family to be called Melicertadae, and in this he
would include two genera, Melicerta and Megalotrocha, de-
grading some of the present genera to form species of Melicerta,
and others to constitute three species of Megalotrocha. The
first-named genus would embrace nearly all the solitary
individuals among the tube-dwellers, and the latter those few
which are aggregated by the adhesion of their gelatinous
cases. To the genus Melicerta, as thus constituted, fain
would I add two species — M. longicornis and M. intermedius ;
hut unfortunately the admirable arrangement quoted has been
introduced in so quiet and unobtrusive a manner, in the
pages of a popular journal, that there is some reason for
fearing it may not be generally adopted, at least for some
time ; and this fact determines me to find for the strangers
the least inconvenient place — possibly a temporary one — with

VOL. XV. C

14

Davis, on the genus (Ecistes.

the family (Ecistina, as propounded by Ehrenberg and in-
dorsed by Williamson and Pritchard.

Genus (Ecistes.

( E . intermedins (n. sp.). — Sheath granulate ; pale at the
base, growing dark and opaque towards the open extremity ;
narrow ; tapering slightly downwards. The simple trochal
disc ovoid in outline, and its cilia interrupted in the dorsal
aspect. Beneath the oral aperture a ciliated protuberance,
on each side of which is a setiferous tubercle. Length of
case -jV'* animal about -jy/* (PI* figs. 1, 2, 3, 4.)

This species is plainly a connecting link between CE . crys-
tallinus and Limnias ceratophilli , having the single trochal
disc of one and the tapering tube of the other ; yet a strict
reading of artificial characteristics would undoubtedly exclude
it from either genus, and justify me in absurdly making
another on purpose for it. Limnias requires the mature
animal to have a “ two-lobed rotary organ/’ and (Ecistes a
single lobe, but a “cylindrical case.” In my difficulty I
apply for advice to our highest authority in these matters,
and am recommended to “ call it (Ecistes, but note its resem-
blance to Limnias.”

CE. longicornis (n. sp.). — Sheath solitary ; rarely contiguous,
and imperfectly conglomerate ; floccose ; generally unsymme-
trical and opaque. Animalcule with two long antennae termi-
nated by retractile setae ; thickly ciliated “ chin.” Length of
case tow// 9 animal about -fe" ; antennae -5-^-0". (Figs. 5, 6, 7, 8.)

There are also two varieties of this species, one resembling
it in every particular with the exception of the antennae,
which are replaced by setiferous tubercles, as in CE. intermedius
and in Limnias ; the other variety has a more cylindrical
case, which is slightly annulated, and transparent even when
grown in turbid water.

I find these creatures in ponds near Leytonstone, growing
on leaves of the water ranunculus and other aquatic plants.
Even minute filaments of Confervae are often studded with
their nest-like cases. CE. longicornis is by far the smallest of
the tube-dwellers ; its brown, fluffy, and irregularly formed
sheath is scarcely noticeable under a low power, and to this
circumstance I attribute the fact of its being hitherto over-
looked. The body of the animal, when the disc is retracted,
is somewhat oviform, gradually attenuated to a highly elastic,
deeply corrugated foot-tail. Outside the integument are four
fine lines indicating segments of a delicate carapace ; these

15

Davis, on the genus (Ecistes.

lines form one broad central annulation and two narrow rings
near the head ; to one, apparently the strongest, are attached
the long antennae. The trochal disc at its base seems hinged
in each lateral aspect ; the movements of these curious hinges
are best seen when the animal is slowly expanding, then the
ciliary wreath has a waved and oblong outline. In the
ventral aspect, outside the rotary organ and beneath the
ciliary frill, is an arcuate process forming the cheek of the
buccal cavity or “ funnel,” and below this the ciliated pro-
jection, termed the “ chin ” when applied by Gosse to
Limnias, or the “ additional 99 and fifth lobe ” to Melicerta
by Williamson.*

Atoms of carmine are greedily swallowed by healthy
specimens ; and the whole course of the red particles is
easily watched from their entrance into the buccal funnel
and the mastax, through the curved and undulating oesopha-
gus into the stomach, to their discharge (apparently unal-
tered) from the everted anus.

On treating the animal with solution of potash the foot,
antennae, and rotary organ, are immediately dissolved, but
the integument and the mastax remain unaltered. The latter
is pretty plainly constructed on the plan of Limnias, as
figured by Mr. Gosse in the c Philosophical Transactions
but the required number of teeth — three to each ramus — is,
I think, greatly exceeded ; three teeth are very distinct, and,
I fancy, a fourth and fifth; but as they gradually grow
fainter as they recede from the joint of the rami, it becomes
exceedingly difficult to determine the exact number. Mr.
Gosse’s figure shows a faint striation on the surface of each
ramus, parallel with the three teeth, and extending beyond
them, and it is quite possible that I may have confounded a
similar striation with the teeth, for the exceedingly minute
size of the gizzard in GE. longcornis precludes nil hope of
trustworthy observation on it with the moderately high
powers at my command.

Whatever may be the function of the ciliated “ chin ” in
other species, it appears to me in these to be intimately con-
nected with the formation of the tube ; for on several occa-
sions I have noticed minute particles of the extraneous matter
in suspension drawn across and from the buccal aperture,
and directed by the cilia over the chin into a slight depression
beneath it ; the granules were not rotated nor formed into

* Mr. Slack believes that he has detected an unusually complicated
ciliation of the trochal disc in (E. longicornU. Certainly his skilful handling
of a Beck’s a\jth, with this object and a fine condenser, warrants me in
accepting his opinion with the greatest respect.

16

Piper, on a Portable Slide Cabinet .

pellets, but they simply collected in a spot agreeing with the
position of the pellet-cup in Melicerta. There was evidently
a viscid excretion at the spot which held the extraneous
matters loosely together in a clot ; in about half a minute
the rotifer would jerk down, leave the floccose deposit on the
edge of its case, then rise immediately and repeat the process.
On mixing a little carmine with the water, the process became
very striking ; an irregular crimson edge to the tube was made
under my own eyes, and, on leaving a number of specimens
of both species in a zoophyte trough, charged with carmine,
for forty-eight hours, I was gratified to find that a few had
continued building, and made red tops of different sizes to
their habitations ; nearly one fourth of the entire structure in
two instances were composed of the mixture of the red atoms
and gelatinous excretion. One infant rotifer, whose first
efforts at building I had distinctly marked, seemed to have
made his entire nest of the glowing pigment. The carmine
apparently stimulates the creatures to activity, but certainly
kills them in a day or two. I have mounted, in Deane’s
gelatine, some of the red-topped cases, constructed as
described, and I offer them as confirmatory evidence of the
reliable character of what I advance. They tend to show, not
only that Melicerta enjoys no monopoly in the building trade,
but that all rotifers inhabiting opaque encrusted tubes may
reasonably be suspected of constructing them piecemeal, and
in the same manner.

Finally, returning for a moment to the sheath of CE. longi-
cornis , I would note its great internal elasticity, as shown
especially at the aperture. It always embraces the animal,
expanding or contracting in its movements in rising and re-
treating, and to such an extent that when the rotifer, greatly
alarmed, shrinks down to a mere ball at the bottom of the
sheath, there is generally a coalescence and perfect closing
of the orifice.

On a Portable Slide Cabinet and a Form of Slide for
Opaque Illumination. By Samuel Piper, Old Change
Microscopical Society.

(Read January 9th, 1867.)

The Portable Horizontal Slide Cabinet is composed of any
number of flat cardboard trays, divided into six or more

Piper, on a Portable Slide Cabinet . 17

compartments, each holding a single slide in a horizontal
position.

The trays are enclosed in a strong millboard box, the front
of which is made to fall down, so as to permit the trays to be
readily withdrawn. When closed, an elastic band renders
the whole firm and secure.

It may be made of any desired capacity. Specimens are
placed on the table capable of receiving from six to two
hundred and fifty slides. The smallest is well adapted to
contain a “ half-dozen series” of anatomical or other subjects;
and its great strength, combined with lightness, makes it
peculiarly available for transmission through the post.

The one figured above is, however, that to which I would
more particularly call your attention, being of a convenient
size, and suitable for carrying in the pocket. It contains six
trays, and will therefore hold three dozen slides.

Amongst the advantages which may be derived from the
use of these cabinets I will mention the convenience of dis-
playing at one view the entire collection of slides, and the
facility thus afforded for the selection of any required speci-
men without the troublesome search and difiiculty of
removal frequently experienced with the old form of box, in
which the slides are dropped (out of sight) into perpen-
dicular grooves. It also prevents the possibility of the covers
becoming detached by shaking about in transit, which is im-
portant when it is required to convey a rare or valuable
collection.

The trays, being all of uniform size, may be transferred
from one cabinet to another of larger or smaller dimensions

18 Piper, on a Form of Slide for Opaque Illumination.

without necessitating the disturbance of the slides. In addi-
tion to its portability, it possesses the merit of cheapness,
durability, and neatness of appearance.

It may be obtained in its various forms from all the lead-
ing microscope makers in London.

On a Form of Slide for Opaque Illumination.

I would also beg to oiler to your consideration a form of
slide which meets a want frequently felt in mounting opaque
objects for the binocular microscope, so that they may be ex-
amined without the intervention of a glass cover, and, at the
same time, to have adequate protection against the intrusion
of dust or other foreign matter when not in use.

It is especially adapted for botanical or geological speci-
mens, and for objects of considerable thickness requiring a
deep cell.

It consists of the usual mahogany slide, with the addition
of a thin circular disc of bone or other convenient material,
which is attached on one side of the central cavity by means

FIG. 2

a, Mahogany slide ; b, central cavity ; c, covering disc (turned
aside), bearing descriptive label; d, pivot on which the cover
rotates.

of a split metal rivet, the ends of which are turned outwards,
on the underside, before the black paper and cardboard
bottom are applied ; this rivet acts as a pivot, on which the
cover rotates, so that it can be instantly turned aside for the
display of the object, and as readily replaced when the slide
is returned to the cabinet. The cover is also available for
the application of the label bearing the name and description,
and can be applied in a few minutes, at an increased cost of
about twopence per dozen upon the price of the ordinary
slides.

By substituting a thin glass instead of the cardboard
bottom it may be used for Lieberkiihn illumination.

19

On the Crystallization of the Sulphates of Iron,
Cobalt, and Nickel. By Robert Thomas.

(Read January 9th, 1867.)

The object in view, in crystallizing the salts of the mag-
netic metals, being to ascertain whether there is any relation
between the magnetic principle in those metals and the action
which takes place in the crystallization of their salts, ex-
periments have been made with a less number of atoms of
water than are usually found in the natural crystals of these
salts, and the results of these experiments are here submitted
as indications of the possibility that some such relations
exist.

Faraday has shown* that a crystal of sulphate of iron “is
compounded of superposed flat crystals or plates, and that
the magne-crystallic axis goes directly across these.” After
many trials, the writer has been able to get these “ plates ”
to form on the “ slide,” which may be done as follows : —
Take a concentrated solution of sulphate of iron, with a small
quantity of sugar to prevent oxidation of the film of iron.
Drive off the water as rapidly as possible with a “ Bunsen's
burner ” or “ spirit-lamp,” and when nearly dry the “ plates ”
will form, and, if carefuily watched, their formation may be
seen even by the unaided eye. Then place the slide quickly
at a higher temperature, and further crystallization of the
plates will be arrested. When perfectly dry, the slide should
be kept at a temperature of about 65° Fahr. ; but these pro-
cesses (even when great care is taken) are influenced much
by the state of the atmosphere. If it be too moist, the
foliation (seen in the specimens) will proceed from all points
of the “ plates.” The slide should then be placed at a higher
temperature, when the foliations will proceed only from each
pole, or from the ends of the longest diameter of the plates,
and curve backwards towards the opposite pole, exhibiting
the same configurations as iron filings when arranged round
the magnet, the crystalline force appearing to flow in the
direction of the magne-crystallic axis described by Faraday.

Specimens of the crystals of the salts of cobalt and nickel
are also shown, which clearly indicate that they all have the
same mode of formation as, but less definitely marked than,
those of iron. And if the relationship to which reference has
been made should be found to exist, this less perfect crystal-

* Series xxii, § 2546.

20

Tomkins, on a Travelling Microscope.

lization of the salts named would naturally follow from the
fact of the metals themselves being less magnetic.

Note. — My friend Mr. Thomas having having presented me with some
crystallized specimens of sulphate of iron, cobalt, and nickel, of great
novelty and beauty, I solicited him to write a short description of what
they were intended to illustrate, and also his method of producing them,
thinking it would be interesting to the Fellows of the Royal Microscopical
Society.

In his letter to me he says, “ If any one can offer a better explanation I
shall be gratified. In trying to produce specimens there will be many
failures, and it will require a considerable amount of practice and patience
to produce similar results.” — W. Ladd, 11 and 12, Beak Street, W.

On a Travelling Microscope.

By J. Newton Tomkins, F.R.C.S., F.Z.S., F.R.M.S.

(Read January 9th, 1867.)

I am desirous of bringing before the notice of the Society a
new microscope stand which possesses many points of merit,
and is quite novel in some of its arrangements. The aim has
been to combine lightness and extreme portability with
steadiness and efficiency of work, while the essential element
of cheapness has not been lost sight of. The whole apparatus
is contained in a sling case, similar to that used for race-
glasses, and weighs somewhat under two pounds ; it has
been appropriately called the “ Travelling Microscope,” from
its manifest capabilities. The compound body is firmly
attached to the front leg of the tripod stand, the two other
legs are supported on capstan-bar joints (to be tightened at
pleasure should they work loose), which fold up when not in
use. The tripod forms an exact equilateral triangle, with the
view of ensuring the greatest possible steadiness, and the feet
are shod with cork in order to diminish vibration, as well as to
prevent the instrument from slipping on a smooth table. The
tube, which allows of elongation to an extent of eight inches,
slides in a jacket lined with cloth, and the coarse adjustment
is gained by this sliding motion ; the fine adjustment is
effected by means of a tangent screw of fifty threads to the
inch, which is placed conveniently behind the body, and
worked by a milled head acting on a spring contained in the
upright which supports the body. This portion of the instru-
ment works smoothly and satisfactorily.

The stage is formed of a simple brass plate, with spring

21

Tomkins, on a Travelling Microscope.

clips to hold the slides; but should greater accuracy be desired,
a mechanical stage capable of affording traversing movements
in two directions can be added. Beneath the stage, and
secured by brass pins working in slots, room is found for
a Varley’s live-box. The nose-piece is furnished with the
Society’s universal screw, thus being adapted for most modern
object-glasses.

By way of utilising the limited space to the utmost, the
legs permit of being detached by help of bayonet-catches,
and contain, severally, dipping tube, forceps, and two dissect-

ing needles. A small case, placed near at hand, holds a glass
slide with ledge, and a reserve of thin covering glasses. The
optical portions of the microscope, viz. the object-glass, eye-
piece, and mirror, are of the usual description. The fishing
apparatus that I use with this instrument is simple, but very
effective. The rod is the common landing-net rod of the
angler ; into this is fixed a gun-metal ring, which carries a
bottle provided with a screw, and which may be obtained of
any chemist. A small net, a metal spoon (indispensable
when hunting for diatoms), and one or two gutta-percha
bottles, preferable to glass because lighter and not liable
to breakage, complete the equipment.

This microscope especially recommends itself to the atten-
tion of field-naturalists, since every one who has made the

22 Anniversary Meeting.

Protophytes and Protozoa his study is aware how difficult, if
not impossible, it is to bring home many of these delicate
organizations from any distance in a living state. Of this
class may be mentioned some of the more tender of the
oceanic Hydrozoa, the free-swimming larvae of the Crustacean
family, the Antheridia and Antherozoids of the ferns, and
innumerable others.

The naturalist who may be possessed of an instrument
like that herein described will now be enabled to prosecute
his researches under the most favorable circumstances, and to
select from his gatherings of the day only those portions
suitable for future examination.

The whole merit of this arrangement is due to Mr. Moginie,
of Mr. Baker’s establishment, a member of our Society ; it is
only after many trials that he has succeeded in bringing the
“ Travelling Microscope ” to its present effective form.

I am not exactly aware of the price at which Mr. Baker
will supply these instruments, but believe that it will not
exceed £3, including one eye-piece, but exclusive of the object-
glass.

ROYAL MICROSCOPICAL SOCIETY OF LONDON.

Anniversary Meeting.

February 1 3th, 1867.

James Glaisher, Esq., President, in the Chair.

After the usual routine business,

Walter Kerr, Esq., Cedar Road, Fulham Road; Oliver
Codrington, Esq., Surgeon, 68th Light Infantry; John
James Hamilton Humphreys, Esq., 16, Torrington Square;
were balloted for and duly elected Fellows of the Society.

A report from the Auditors of the Treasurer’s accounts
was read.

It was resolved — “ That the President’s address be printed
without delay.”

The meeting then proceeded to ballot for Officers and
Council for the year ensuing.

At the close of the ballot the scrutineers made their

Anniversary Meeting. 23

report, when the following gentlemen were declared duly
elected :

President. — James Glaisher, Esq., F.E.S.

Vice- Presidents .

Charles Brooke, Esq., F.E.S. Arthur Farre, M.D., F.E.S.

E. J. Farrants, Esq., F.E.C.S. Eev. J. B. Eeade, M.A., F.E.S.

Treasurer. — C. J. H. Allen, Esq., F.L.S.

Hon. Secretaries.

Jabez Hogg, Esq., F.L.S. | H. J. Slack, Esq., F.G-.S.

Council.

Geo. E. Blenkins, Esq., F.E.C.S.
W. L. Freestone, Esq.

James Hilton, Esq.

Eobert Hudson, Esq., F.E.S.
AVm. Henry Ince, Esq., F.L.S.
Henry Lee, Esq., F.L.S.

Ellis G. Lobb, Esq.

E. Mestayer, Esq.

John Millar, Esq., F.L.S.
Major S. E. J. Owen, F.L.S.

F. C. S. Eoper, Esq., F.L.S.
F. H. Wenham, Esq.

The thanks of the meeting were then voted to the Pre-
sident, Secretaries, Treasurer, and Council, for their services
on behalf of the Society during the past year.

Report of the Cabinet of Objects during the past year.

Number of objects in the Cabinet on February 14th,

1866 1389

Presented by Colonel Samuel Hennall, March, 1866,

twelve slides of Diatomaceae . . , .12

Presented by Major Owen, June, 1866, cne slide of

Foraminifera ....... 1

Presented by Thomas Shearman Ralph, Esq., of Mel-
bourne, January, 1867, twelve slides of Blood-
spherules . . . . . . . .12

Total quantity of objects now in the Cabinet . . 1414

Ellis G. Lobb.

24

Auditors' Report.

CM

*3

trs00<M©00©

00«0>MN^ri<
H i”H

CM^OOCO— ICOCOO
if5 CS t—l CO

CM

CO t>- J O 1ft
CM ^ | O O

U 03 ^0

oj ^3
*

-J a <4-1

<1 o °

!-

'O

oS

PP

<4-1

© <»

. S-«

O

1-S

03

to

*o

«©
ce ".03

CC

czj

-g

©S "O
(O R

O

Ph

S3

PP

o

H

o

r—H

ert

o

03

X!

W

_►»

03

Ph

03 "S

ll ~

-tj 03 es
_2 r-) -*>

35" g

U»

ns 3

33 to o
2 tf .5 p
'c 5 -£ -X!

2 C. s O

3 5J'u *

RPPPhR

03 s!<j 3
<J2 „ a

4-0 “ • —

g O o

C3

S" S

'33 £-3

C/3 C3 «3

<1R pq

-^jOOOOO ooo

^TfloONOOO CM^r— I

p— I H H

OfMNifl tOOO

OW °S

i— I r— I ©*

oooooooo | . .

J2 hccsn^nom I

. _ O (—1 r— I I— I rH

^§S ° ^ _ ! . .

Is r£ 3

« * s

m w *•

^ s «

^ _0 J2 w OS

• •

= S |

SSoor-I^CO J3r-ICMCO'<^*OCOt-.00
£ TfH ^

• X . ^ Ooooooooooooooooo

> O ^

p,S E*o «o-s'§ .

O fjy — O m &■*“> *'*'*“*" ** ** "3

O O .-£ *5 ^ ®

*§ S-Sto= g£*

8 S2 gg-s s S * - - s * * e-2

J s ' I- % Ih £2

ctf ^3 O > «- s- oo

OH £3

>4

■o r

£§

rx ^
£ o

..SO
JZ) CM

S3

«“ T3

g J

3 fcO

c/3 c

S R

Ho

03 XC

R 5
^ PP

J 2 .

6-o

«3 C rH
x •-
« 03 6,'
03 O OS

So

03

£;^_g
£ = o

= | 1
03 03

J: o

C3§ g.

£ £ ST

»

V.

<s

r*>

25

The President’s Address for the year 1866-1867.

By James Glaisher, Esq., F.R S., &c.

The year 1866-7 will be memorable in the annals of the
Microscopical Society, as that in which a Royal Charter was
obtained for its incorporation, in which Her Most Gracious
Majesty Queen Victoria was pleased to signify her dis-
tinguished appreciation of its objects, by commanding it to
assume the title “ Royal,” and in which H.R.H. the Prince
of Wales conferred upon it the honour of becoming its
patron.

During the past year the general condition of the Society
has been one of prosperity : its members have augmented,
its meetings have been well attended. Many subjects of
interest have been brought forward in the papers that have
been read before it ; the discussions thereupon have elicited
much information of general interest and value.

The number of new Fellows elected during the year has
been 51 ; the number lost by death and by resignation, 6.

In adverting to the loss this Society has sustained during
the past year through the death of its members, I have to
mention Dr. Ansell, Richard Beck, Dr. Lee, Dr. Hinxman ;
and the loss to Microscopy in general, though not a member
of this Society, of Dr. Greville.

Thomas Ansell was a very diligent student both in London
and Edinburgh. He graduated at the University of St.
Andrew’s, and obtained the diploma of the Royal College of
Surgeons of England. After this he made a voyage to China,
and on his return settled at Bow, where he steadily pursued
his profession and obtained a high position. He was elected
twenty-five years ago one of the Examiners of the Society of
Apothecaries ; and six years since he was unanimously chosen
Chairman of the Board, and continued in this position till
his death Under the recent Act, he was elected Officer of
Health for Bow, in Middlesex ; and in the performance of the
duties of that office he was distinguished for his zeal, and it
was whilst in their discharge, at the outbreak of cholera in
his district, in July, 1866, he died of that disease.

He was an ardent lover of Natural History, and a good
observer ; he was not an original contributor to Microscopical

26

The President’s Address.

Science, though he readily comprehended, and almost instantly
appropriated, everything which was new and valuable.

Iiis fine library and microscopical museum bear testimony
to his judgment and taste. He was an able practitioner, a
good anatomist, and possessed an ample knowledge of general
physics.

Richard Beck was born in October, 1827, at the then
residence of his parents, Tokenhouse Yard, London ; his
father being a partner in the well-known firm of Lister and
Beck, wine-merchants. As is often the case with men who
distinguish themselves in particular pursuits, Richard Beck
did not in his boyhood evince much aptitude for the ordinary
routine of scholastic teaching. He is described as more fond
of play than of books, and his manifestations of talent and
ability were in the direction of mechanical pursuits. This
inclination was judiciously fostered in a school at York
where he finished his education. . At this time (1841) his
parents perceiving that the manufacture of the microscope
was likely to rise in commercial importance, made arrange-
ments that Richard Beck should learn the business by serving
for three years under Mr. Smith, an excellent workman
engaged in carrying out the views of Mr. Joseph Lister and
other distinguished members of this Society. Previous to
this period much had been accomplished by Mr. Pritchard,
Mr. Powell, and Mr. Ross ; the two latter having greatly
distinguished themselves by giving practical effect to the
optical principles made known by Mr. Lister in 1829 ; but
both in methods of manufacture and in many important de-
tails of construction there was still much to be desired and
accomplished, and it was mainly through the skill and the
exertions of Richard Beck that the well-known firm of Smith
and Beck, formed in 1847, took such an important position
in the microscopic world, and, by maintaing an honorable
rivalry with the other great makers, effectively contributed
to bring the English microscope to its present degree of
optical and mechanical perfection.

Important improvements in the mechanical stage and
in methods of illumination owe their origin to Richard
Beck, and when Mr. Wenham devised his admirable
arrangements for binocular vision, they were promptly
carried out under his skilful supervision. In devising
microscopic apparatus adapted for special investigations,
Richard Beck exhibited great ingenuity; and when the ideas
of other inventors were communicated to him, he usually
endeavoured, and frequently with success, to improve upon
them before giving them practical effect. As a microscopic

The President’s Address.

27

observer he took a high place, as numerous communications
to this Society abundantly show. He was slow in forming
conclusions, very searching in investigation, unwilling to
take anything for granted without submitting it to careful
verification, and very open-hearted and generous in com-
municating to others the facts which he had ascertained, and
the conclusions to which he had arrived. As a manufacturer,
he brought a high degree of natural intelligence and a culti-
vated understanding to bear upon mechanical pursuits, never
allowing the requirements of trade to overpower his zeal in
the cause of science, or his commercial connection with the
microscope to interfere with his appreciation of it as an in-
strument of research. In addition to the production of first-
class instruments, the firm of which he was a member intro-
duced at various times constructions devised by himself to
meet the wants of a less rich class of students, such as the
“Educational Microscope,” the “Universal Microscope,”
and the “ Popular Microscope.” In 1865 Mr. Beck pub-
lished a “ Treatise on the Construction, Proper Use, and
Capabilities of Smith, Beck, and Beck’s Achromatic Micro-
scope,” in which many valuable suggestions are contained.
This work is illustrated by some of the best plates of micro-
scopic objects that have been produced, several being from
his own drawings. The frontispiece gives representations of
the Podura scale as seen with powers from 80 to 1300, and
presenting those appearances which microscopists have ac-
cepted as tests of the true correction of their objectives, and
of their methods of illumination. As a member of this
Society, Richard Beck rendered constant and valuable service
by contributing to its f Transactions ’ and taking part in its
discussions. Great grief and pain were felt by his numerous
friends and acquaintances when his valuable life terminated,
at the early age of thirty-nine, on the 20th of September
last, through a disease of the heart, first contracted when
suffering from rheumatic fever at School, and which had been
suddenly aggravated six months previous to his decease.
He was buried in the graveyard attached to the Friends’
Meeting-house at Stoke Newington, and your President, ac-
companied by several members of the Council, attended on
the occasion to manifest the respect due to him for his many
excellences of character, and for his numerous services to
Microscopical Science.

John Lee, LL.D, F.R.S., of Hartwell House near
Aylesbury, who died on the 25th February last, was elected
amember of this Society in 1841, but never took any active part
in microscopical pursuits. His attention was chiefly devoted

28

The President’ s Address.

to astronomy, and he founded one of the best private obser-
vatories in the country. He was elected to the office of
President of the Royal Astronomical Society a few years since.
By those engaged in his favorite study, as well as by many
devoted to other branches of science, he will long be remem-
bered for the encouragement and assistance he was at all
times willing to afford.

Robert Kay Greville, F.R.S.E., although not a member
of this Society, has contributed so many valuable papers to
our f Transactions,’ and was so well known as a distinguished
cryptogamic botanist, that his loss cannot be passed over in
silence. He was born at Bishop Auckland, in Durham, in
1794, and died at his house at Murrayfield, near Edinburgh,
in June last, after a few days’ illness. From an early age he
had been devoted to botanical pursuits ; and though he
entered the medical profession, he devoted himself entirely
to his favourite study as soon as he came into possession
of independent means. In 1824 the University of Glasgow
conferred on him the degree of LL.D. Uniting great
energy of character with a quick discernment of the minute
distinctions which characterise a large proportion of the
Cryptogamic series of plants, he at the same time possessed
such artistic skill, that few could rival the exquisite drawings,
especially of the microscopic plants, which were procured by
his pencil. His earlier well-known works, the f Scottish
Cryptogamic Flora,’ and the ‘ Algae Britannicae,’ published
between 1823 and 1830, although containing some micro-
scopic species, and illustrated by microscopic dissections,
were chiefly devoted to a description and delineation of higher
tribes of cryptogams, and are still unrivalled for the beauty
and correctness of the drawings which illustrate the species.
On the death, however, of his friend Dr. Gregory, he
devoted himself almost entirely to the study of the beautiful
siliceous frustules of the class of Diatomacea, to which he had
been attracted by the illustrations of the papers at various
times contributed to our own and other societies by that
author; and since 1857 he has contributed twenty-nine papers
on this branch of study to our f Transactions ’ and ‘Journal,’
besides contributions to the c Annals of Natural History,’ the
4 Edinburgh New Philosophical Journal,’ and transactions of
the Botanical Society of Edinburgh.’ He devotedhimself more
especially to the delineation and description of forms hitherto
unnoticed ; and though some may consider that many of
these will prove on further examination mere varieties, and
not entitled to rank as distinct species, and that his labours
would have had more scientific value if employed in the con-

The President’s Address.

29

soliclation rather than the extension of an already over-
burdened nomenclature, none can fail to admire the beauty of
the drawings which accompany his papers, or to wonder at
the perseverance which, at threescore years and ten, enabled
him to examine critically hundreds of slides to select those
forms which had not previously been illustrated.

Mr. Joseph Gratton belonged to a very valuable class of
men— those who, being engaged in commerce, devote their
money and leisure time to scientific pursuits. He took
interest in microscopical investigations, and manifested a
liberal disposition by freely showing, with other objects of
interest, those which his foreign transactions enabled him to
obtain abroad.

Passing from subjects of painful association, it is gratifying
to revert to the favorable position occupied by the Society,
as the number of new Fellows added in the year, over the
number lost by death and resignation, amount to no less than
forty-five.

I will now briefly advert to the subjects which have been
brought under our notice since my last address. An inquiry
into the whole microscopic work of the past year would far
exceed the limit of this address ; and indeed my long illness,
and consequent absence from the meetings of the Society
during the last four months, places it beyond my power. I
must therefore limit myself to a brief notice — to a few points
only.

At the first meeting of the Society in the year, viz., on
March 14, a valuable paper was read by H. C. Bastian, M.A.,
“ On the so-called Pacchionian Bodies.” In this paper those
bodies were shown to be in no way glandular in their com-
position, as was formerly supposed, but to be composed of
precisely the same elements as entered into the formation of
the arachnoid, of the visceral layer of which, they were local
hypertrophies, or circumscribed outgrowths. Their various
forms were described, and the situations in which they were
encountered in their different stages of growth were accounted
for. It wTas maintained, in opposition to some other observers,
that these growths invariably sprang from the visceral, and
never from the so-called parietal layer of the arachnoid. The
causes leading to their development were considered, and also
the questions as to whether such growths were to be regarded
as normal or pathological formations. And, lastly, it was
shown that the Pacchionian bodies were not growths, abso-
lutely peculiar in kind ; that they could be classed with
similar growths occurring on other organs of the body ; and

VOL. xv. d

30

The President’s Address.

that their increased development was not usually a matter of
much pathological significance.

With regard to matters relating to the practical adaptation
to the microscope, or improvement in apparatus, we have to
notice Dr. Maddox’s “ Slide-clip” for holding on glass covers,
either at the time of mounting or during temporary observa-
tions. This contrivance is simply made from a piece of brass
wire.

At a subsequent meeting, a different form was explained by
Mr. J. Hogg, as manufactured at a very small cost per dozen
by Mr. Baker. One of the prongs of this clip is armed with
a small disc of cork, and the opposite one is turned in the
form of an open ring, through which the proper position and
arrangement of the object may be seen. These clips will
unquestionably be found to be of great service in mounting
objects, and maintaining a pressure till the object is dry
or the medium properly set.

Next in order, is a form of adjustable diaphragm by Mr.
S. Kincard. This consists of a very thin piece of vulcanized
india-rubber tube set in a brass mounting so as to admit of its
being twisted. In this operation every portion of the cir-
cumference of the tube, midway between the ends, gradually
approaches towards the axis, and forms a variable aperture
sufficiently uniform in outline. But the possible objection to
this may be that the aperture is too far below the condensing
lens, thus making it produce as much an effect of reduction
of light as of diminished aperture.

Among other instrumental objects that have been brought
before us is an ingenious leaf-holder and revolving disc-
holder, by Mr. Smith, and an adjustable diaphragm eye-piece
by our Secretary, Mr. Slack : this was devised for the pur-
pose of limiting the extent of the luminous field, so as to suit
the shape of any object through which it was desirable to
transmit a strong light. By shutting out all extraneous or
useless light, and admitting that only which comes from the
object or part of the object under view, it is evident that we
can see delicate structures far more correctly and comfortably
than when surrounded with a large field of bright light that
almost blinds us. This diaphragm can be arranged so as to
enclose an object of irregular figure, and it will also serve as a
pointer, as the aperture may contain only that portion of the
object required for demonstration : the arrangement is neatly-
fitted into an ordinary eye-piece, and in no way interferes
with its general use.

The most important improvement in the year relates to
new forms of binocular microscope, by means of which the

The President’s Address.

31

whole of the aperture of the object-glass may be obtained in
each eye with the highest powers. The first plan for this
purpose was brought before us by Messrs. Powell and
Lealand, the second by Mr. Wenham: neither of them is
intended to produce the peculiar stereoscopic effect resulting
from the combination of two views of the same subject taken
at different angles, but they have been devised to secure the
physical convenience of using both eyes at the same time.
To obtain an image by the whole aperture of the object-
glass in each tube, Messrs. Powell and Lealand interposed an
inclined disc of glass with parallel sides, so that one set of
rays from the object are transmitted direct through it, while
another portion of the light is reflected by the glass surface,
and again reflected into the second tube ; or, in other words,
one portion of the light proceeds through the glass disc up one
tube, while another portion reflected from it, suffers a second re-
flection from a rectangular prism, and is directed up the other
tube. Considerable success is obtained by this method. Messrs.
Powell and Lealand are able to display by it both sets of lines
on the Pleurosigma rhomboides with only an infinitesimal
loss of definition, yet the difference in brightness between
the two images — one formed by transmitted, and the other
by reflected light — is considerable. Mr. Wenham, noticing
this great difference between the amount of light sent to
each eye, called attention to the fact that at an angle
of 45°, only 53’66 out of 1000 incident rays, or about

th part, could be reflected from a glass surface ; and to
obtain a more equal illumination, he devised the highly
ingenious combination of prisms described and figured in
the f Proceedings’ of the Society, as reported in the f Quar-
terly Journal of Microscopic Science’ for July, 1866. Mr.
Wenham’s remarkable manipulative skill enabled him to
realise to a very important extent all the results he anticipated,
but our leading professional artists consider his plan difficult
of execution, and have not yet made the new combination of
prisms for sale.

This is to be regretted, because there can be no doubt of
the merit of his invention, and it seems to offer the best mode
of avoiding the bad effects of a too exclusive use of a single
eye, which, as is well known, tends to derange its power of
focussing consentaneously with the other eye. It is also
probable that in the prolonged examination of objects, better
vision would be obtained by two eyes than one, as the organ
of vision would be less fatigued.

Mr. Wenham in his paper embodied several plans in which
the reflection was obtained from two contact surfaces, by

The President's Address.

which means the luminosity of the reflected image was greatly
increased, and a more equal illumination transmitted to each

eye.

The arrangement exhibited and recommended by the
inventor does not differ materially in form and outline from
his well-known form of binocular prism, and fits into the
same space in the common double tube : the addition of
another triangular prism in contact with the first reflecting
surface allows direct rays to pass straight through into the
eye-piece, while the others are reflected obliquely as usual.
The plan is apparently simple ; but the objection raised against
it is, that the difficulties of construction are so great that the
inventor only is capable of making them. It is to be hoped
that this assertion is unfounded.

A somewhat different plan has been carried out by Mr.
Ahrens, in which the principle of two combined reflections
is still made available as in Mr. Wenham’s; but as the di-
rect rays are thrown out of the axis, two new bodies would be
required for its application. The several plans for obtaining
the whole aperture in each eye so quickly following upon
Messrs. Powell and Lealand’s arrangement, shows that an
effect not depending upon a solitary condition may still afford
ample scope for inventive ingenuity ; but it is candidly ad-
mitted that combining an object with its own identically
reflected image will give no stereoscopic relief, and conse-
quently afford but little assistance in defining the projections
and depressions of organic structure ; yet it remains to be
proved whether in carrying the now habitual use of two eyes
in observations with the low powers, on to the more trying-
investigations with the highest, may not afford relief, and
enable some observers to continue the use of the instrument
beyond the time which sometimes compels them to lay aside
the microscope, from the distress and injury to sight occa-
sioned by employing one eye only for too long a period
beyond its powers of endurance.

Mr. Piper has brought before us an economical and
convenient cardboard cabinet for objects, and a mode of
making a slide with a movable cover for the preservation of
objects which it is desired to view, without the interposition
of a covering glass. It must be admitted that it is much
better, when practicable, to examine objects as nearly as
possible in their natural state, and these slides may assist in
the preservation of many objects without the flattening and
distortion incident to the usual mode of preparation.

Mr. How has brought before us a useful and economical
substitute for a mechanical stage, which he has attached to his

The President's Address.

33

new cheap microscope. Its action is like that of the mag-
netic stage, but the requisite adhesion is obtained by suitably
placed springs, which oppose a convenient resistance, and do
not seem likely to get out of order.

A simple adapter has been devised by Mr. Richards ; it
consists of a tube which passes through the stage of the
microscope, and is sufficiently long to reach within focussing
distance of the bottom of the stand, thus enabling an observer
to view objects on a level with the base of the instrument,
or to perform manipulations on the table.

A paper was read by the Rev. J. B. Reade, describing
some improvements on his former “ Kettledrum Illuminator.”
By superposing another somewhat smaller hemispherical
lens, he is thus enabled to extend the angular aperture of the
illuminating pencil to its utmost limits, and the large area of
the lenses gives a great quantity of light. By the addition of
ingeniously contrived shifting apertures and stops of various
forms, he is enabled to throw light on the object from every
angle, either in one or in several directions together, or to
entirely obscure the central rays for viewing objects with
dark-field illumination. This contrivance of Mr. Readers
affords a very slanting illumination, and its want of achro-
maticity is stated by him not to interfere with the particular
purposes for which it was designed.

To obtain oblique illuminations in two directions for the
display of the Pleurosigma rhomboides , Mr. Newton Tomkins
has employed two prisms and two sources of light, arranged
at right angles to each other, with excellent effect.

At our last meeting a new form of field microscope, con-
structed by Mr. Baker, was described by Mr. Newton Tom-
kins. This appears far to exceed, both in portability and
simplicity, anything that has yet been produced. Two of
the legs are jointed from a position near the eye-piece of the
instrument. The body itself virtually forms the greater part
of the length of the third leg, and is thus set at a very
suitable angle of observation. The arrangement is remark-
able for extreme steadiness, and the stage and mirror, being
low, make the instrument very handy for manipulation.
The legs are removable for the purpose of containing tubes
and other apparatus. These advantages, together with the
low price at which the microscope is manufactured, are good
reasons why its employment should become universal.

This instrument seems to be an improvement on one of
somewhat similar construction exhibited by Mr. Highley at
the last soiree of this Society.

The art of making photo-micrographs with very high

34

The President's Address.

powers has been brought to great perfection by Captain
Edward Curtis, assistant-surgeon U.S. Army. Dr. Maddox
published in the 6 Intellectual Observer’ for July a descrip-
tion, accompanied with illustrations copied from the original
of Captain Curtis’s photographs of the Pleurosigma angu-
latum , one being taken with an American objective of 4th
focal length, and another ;with a -Ajdh of Powell and Lealand,
the former being worked to an equal power with the latter
by means of an achromatic concave amplifier used instead of
an eye-piece. In these photographs, hexagonal markings
appear with powers of 2344 and 2540 diameters, and nearly
circular markings with magnification of 19050 diameters.

In the August number of the f Intellectual Observer, ’ Dr.
Maddox published a description of the process employed,
from which it appeared that Captain Curtis used a Silber-
mann’s hcliostat, and that the light was transmitted through
a cell containing a saturated solution of ammonia-sulphate of
copper, and thus rendered approximately monochromatic.

At one of our recent meetings, Mr. How exhibited, by
request of Dr. Maddox, a beautiful series of Captain Curtis’s
photo-micrograplis obtained with various powers.

It is impossible not to admire the truly scientific and
disinterested spirit which led Dr. Maddox to bring what
might be considered rival work before the English public.
But while assigning a very high degree of merit to the pro-
ductions of Captain Curtis, it is only just to remark that in
many cases, where his labours and those of Dr. Maddox have
taken parallel lines, the high reputation of the latter has on
the whole been fully maintained.

In the application of the microscope to natural history
investigation during the past year, much worthy of notice
has been achieved, if no very remarkable discoveries have
been made. One paper, though properly belonging to an
earlier period, was only made known to the English student
by a translation which appeared in the f Annals of Natural
History’ for March, 1866 ; and it is now alluded to on account
of the important lesson which it teaches of the necessity of
examining the delicate structures of soft creatures without
disturbing their normal condition. Professor Schjodte de-
monstrates in this paper that the louse (pediculus) has a
suctorial, and not a biting mouth, as was often stated. He
found that the common practice of flattening the organs of
this creature under glass gave rise to completely false
appearances, and that it was only by surveying the parts in
their natural condition that the true structure could be
ascertained.

The President’s Address .

35

One of our Fellows, Mr. Davis, has recently brought before
us some highly interesting and novel rotifiers, which he has
placed provisionally in the genus iEcistes ; and from the dis-
cussion that ensued when his paper was read, it is evident
that there is a very useful field for microscopic work in the
re-examination of the ciliary apparatus of rotifiers with the
best means of illumination, and with the highest powers that
can be brought to bear without necessitating a compression
of the animals to such an extent as would introduce appear-
ances as fallacious as those which Professor Schjodte has
dissipated in the case of the louse.

A paper, published in Germany,* by Dr. Ferdinand Cohn,
of Breslau, on a series of interesting forms of Infusoria which
appeared in a marine aquarium, ought to stimulate English
observers, who have excellent opportunities for adding to our
knowledge of the microscopic life of our coasts.

Fresh-water infusoria have been studied much more
attentively than their marine relations ; but Professor Cohn’s
paper shows how much may be done with a marine aquarium
only twelve inches high and twenty inches in diameter.

The question of iUuminatory apparatus still exercises the
skill of inventors and constructors. Achromatic condensers of
various sizes and combinations are now before the public,
and attention has been called to the different effects which
result from various proportions in which the central and
perij)heral rays bear to each other. Combinations of larger
lenses with longer focal lengths may be made to work with
the same angle of aperture as smaller lenses with shorter
focal lengths ; and it is evident that the central rays are a
constant quantity, while the peripheral rays may be increased
by larger and suitably made combinations.

An achromatic condenser intended for research into un-
known structures should have one stop in which the peri-
pheral and central rays bear such proportion to each other as
to facilitate the penetration of the object-glasses, and at the
same time not to involve too great a sacrifice of surface
vision.

The quantities known as penetration and resolution stand
in necessary contrast to each other ; but as a due proportion
of angle of aperture to focal length secures a useful combina-
tion of the two properties in object-glasses, so a due propor-
tion of the slanting and direct rays brought to a focus by a
a condenser will help to preserve the balance required for
most natural history investigations.

# * Zeitschr. f. Wissenscli. ZooL,’ Bd, xvi, Heft I860,

36

The President's Address.

An achromatic condenser, made by Mr. Ross, with a large-
angled -Vths, possesses in a high degree the properties alluded
to in these remarks ; though Messrs. Powell and Lealand’s
large-angled condenser must be preferred when difficult
surface markings are to be displayed.

Professor Smith, of Kenyon College, U.S., whose name is
well known to English microscopists, is now in this country ;
and he has brought with him a series of remarkably beautiful
drawings of diatoms in a live state, illustrating new views of
their structure and mode of propagation. These it is hoped
he will be able to show at the next meeting of this Society,
and to add explanations of the curious and important results
at which he has arrived. English observers have, in too
many cases, confined their attention to dry and dead valves
of the diatoms ; but it may he expected that Professor Smith’s
researches will excite renewed attention to the living forms.

Professor Smith has likewise brought with him a binocular
eye-piece adapted for use with a single-tube microscope,
which is considered by those who have tried it in this country
to give much better results than had been previously obtained
by a similar construction. He has also devised a mechanical
finger, which is described in c Silliman’s Journal,’ No. 123. In
this instrument a movable arm readily attached to the
microscope carries a bristle, which can be made to touch and
lift up any minute object seen under a moderate power on a
glass slide. As soon as the mechanical finger has caught the
object, it is raised, and a clean slide placed on the stage. The
bristle carrying its minute .burden is then brought into focus,
and made to deposit it on the centre of the slide. With this
little instrument very minute objects can be sorted and
arranged with great ease.

Last year, illuminators for opaque objects under high
powers were brought before the Society by Messrs. Powell
and Lealand, and Richard Beck. They were both founded
upon plans originally tried by Professor Smith, who did not
like their performance, and he is now able to show us the
form of metallic reflector which he recommends, and which
affords better results. Mr. Smith, of Bow, has likewise de-
vised an arrangement slightly differing from that of Professor
Smith, which is well spoken of.

One pleasing feature of our times is the formation of
scientific societies in connection with great mercantile
houses. Foremost amongst these, in point of date, excellent
management, and important success, is the Old ’Change
Microscopical Society, formed in the establishment of Messrs.
Leaf. Your President and Council, appreciating the service

The President’s Address.

3 7

to science that may be rendered by societies of this descrip-
tion, have bad much pleasure in opening friendly relations
with the Old ’Change Society ; and they hope, when you are
better accommodated with rooms in which the instruments and
collections of this Society can be made accessible, that some
arrangements may be made by which a closer connection may
be established with the Old ’Change Society and with similar
bodies.

In inviting you to make renewed efforts for the successful
application of the microscope to the vast range of questions
which it is able to elucidate, I would remark that, as know-
ledge advances, the minute structure of every object belong-
ing to the animal, the vegetable, or the mineral world be-
comes of more importance to the student, because he possesses
additional means for its correct interpretation.

The bodily eye may see ; but if the mental eye does not
perceive, no information is gained. Hence, while improvements
in the structure of the microscope and of its various appli-
ances should be zealously promoted, it is even of greater con-
sequence that the mind should be trained to understand the
appearances which optical art is able to reveal.

Without scientific knowledge, the eye may be pleased with
beauties and wonderful markings made visible by the aid of
the microscope ; but who is there who would not wish that
the result of the devotion of his time, his money, and appli-
cation to the microscope should result in an increase of
knowledge ?

The most common cause of failure with the microscope
results from the want of sufficiently accurate and scientific
knowledge to ensure the correct appreciation and interpreta-
tion of what is seen. There is no purpose of importance to
which the microscope can be directed without a demand
arising for several kinds of scientific knowledge.

The elements at least of physics and chemistry are indis-
pensable in many forms of microscopic research ; and if orga-
nised beings, or portions thereof, are the subjects of investi-
gation, physiology and its kindred sciences become equally
necessary. We cannot, therefore, effectually promote the use
of the microscope without encouraging the study of a large
group of physical sciences. I would particularly recommend
that young observers make themselves acquainted with what
has already been done, and acquire an elementary knowledge
of physics, that microscopic researches may be advanced by
their labours.

It fortunately happens that the acquisition of this know-
ledge, for the most part, does not need a master ; the best

38 McIntosh, on the Gregariniform Parasite of Borlasia .

training results from one’s own industry, one’s own researches,
leading the observer to be self-dependent, and capable of
forming an independent judgment. It is, however, a matter
of the profoundest regret that the important departments of
human knowledge to which I have alluded should be
neglected in the majority of our schools ; and it is also a
matter of deep regret that, in proportion to the size of our
towns and the magnitude of our population, there should be
extremely few institutions in which the elements of scientific
instruction can be obtained, and that there should be an equal
scarcity of public libraries in which the best works can be
consulted.

In conclusion, it is gratifying to revert to the favorable
position occupied by the Society ; and though at present the
Council are unable to announce an immediate success in their
efforts to obtain suitable apartments for the transaction of its
business, fresh applications on its behalf will be made to the
Government; and it is felt that, as Her Majesty has com-
manded the Society to be called Royal, and as His Royal
Highness the Prince of Wales has become its patron, its
claims to receive accommodation, similar to that accorded to
other Societies, are of the strongest kind.

On the Gregariniform Parasite of Borlasia.

By W. C. McIntosh, M.D., F.L.S.

(Communicated by G. Busk, F.R.S., F.R.M.S.)

(Read March 13th, 1867.)

Kolliker, in his contributions to the genus Gregarina,
L. Duf.,* described in 1848 a gregariniform parasite of his
Nemertes delineatus ( Folia delineata , D. Ch.) under the name
of Gregarina Nemertis, which he had found in great numbers
in the general cavity of the annelid. At least, he explains in
a foot-note that his Darm is not the “ Russel ” of Quatre-
fages, but the Darm of Rathke ; and since Quatrefages avers
that Rathke considered the so-called proboscis as an organ of
touch, it may be supposed the general cavity or cavities of
the worm are here implied. He describes the structure of
the parasite minutely, as having a spindle- or club-shaped
body, furnished at its somewhat broader end with a knob
# ‘ Zeitschrift f. wiss. Zool./ Bd. i, pp. 1 and 2, taf. i, fig, 4.

McIntosh, on the Gregariniform Parasite of Borlasia. 39

carried out into a blunt point, and the membranous and
structureless investment containing a number of minute
granules, a nucleus and nucleolus. He adds that their
motion is not very vivacious, but he has seen them moving in
a straight line, and undergoing certain inflexions of the body.
According to the next author, Frey and Leuckart also
observed similar bodies in Nemertes. Max S. Schultze* gives
a drawing and description of a very similar form wThich he
found in Planaria torva. He notes the greater translucency
of the ends of the parasite, and says that he has not observed
a copulation of two individuals to form a cyst and pseudo-
naviculse, but figures some of the latter from a cyst which he
supposes to belong to this species ; he makes no further
remarks on their habits. The late Dr. G. Johnston mentions
the occurrence of these bodies in his Borlasia olivacea3 though
he misinterpreted their nature, for he describes them as
follows :f — “ When pressing a portion of the body ” (of the
Borlasia) “ between the plates of glass, I have occasionally
seen some bodies escape, of a curved fusiform shape, acute at
both ends, and marked towards one of them with a pale
circular spot. They have shown no signs of life, nor can I
say what they are, though it has occurred to me that they
may be embryo young, and that the worms may, in fact, be
o vo -viviparous.”

Whilst examining the structure of some Nemertians at present
classed as different species of Borlasia, these curious grega-
riniform bodies have frequently occurred. In Borlasia octo-
culata and olivacea (which species, however, are not to be
distinguished anatomically), and in long examples trans-
mitted alive from South Devon by the kindness of Mr. Parfitt,
and called by him Linens lactea , after Col. Montagu’s MSS.,
the ova and parasites were abundant, especially in the last
mentioned.

Towards the posterior end of the examples from Devon
these gregariniform bodies occurred in swarms, and they
were identical in all respects with those got in the Scotch speci-
mens of the red and green varieties (PI. II, figs. 1 and 2). They
consist of elongated sacs filled -with minutely granular con-
tents, and having each a single, large, pale nucleus, measuring
from txto th of an inch upwards, according to the bulk of the
specimen. The nucleus shows slight markings when the
parasite is first extruded, but a distinct nucleolus is not very
apparent. In perfect specimens the snout is pale, very

* ‘Beitrage zur Naturgeschichte der Turbellarien/ p. 70, tab. vii, figs.
18—22.

f ‘ Catalogue of British Worms/ edited by Dr. Baird, Appendix, p. 290.

40 McIntosh, on the Greyariniform Parasite of Borlasia.

faintly granular (not quite diaphanous), bluntly rounded, and
marked by a slight swelling of the body at its base, from
which swelling the snout gently tapers. There is no trace of
rough points or other means for adhering. Sometimes, as
when the investment had received injury, the surrounding
water seemed to pass inwards and separate at certain parts
the contained granules from the sheath, a fact which shows
a certain degree of cohesion in the contents in situ .

A favorable opportunity of examining the parasites was
afforded by the spontaneous rupture of some of the annelids.
They may then be seen projecting from the granular paren-
chyma throughout their entire length, with the exception of
the snout, by which they adhere. Indeed, this may often be
seen in the perfect annelid, as the waves of the fluid in the
general cavities bend hither and thither the free bodies of the
gregarinax After remaining for some time in the previously
mentioned position (under pressure), a few separate them-
selves, and move through the salt water with a slow gliding
motion like that of a diatome. On careful scrutiny the
contour of the snout in a moving specimen is observed now
and then to alter ; this motion is not due to currents between
the glasses, and it moves through mucus in the same
manner. After remaining eight or ten hours in water (salt)
all motion ceases, and in some the body becomes altered,
assuming a club-shaped appearance, as seen in fig. 3. At the
same time the clear portion at the snout is almost obliterated
by encroachment of the granules.

Under pressure certain ova that accompany the gregarini-
form bodies are often extruded from the posterior end of the
two first-mentioned worms. In one example of the greenish
variety ( Borlasia olivacea ) they wrere emitted in August last
in the form of an elongated cordon, held together by a slightly
granular gelatinous matrix (fig. 6), the cord being rather
more than the breadth of two ova, and the latter loosely
scattered in the tissue. In the same specimen a mass of ova
of a rounded form, enveloped in the same hyaline granular
tissue, was subsequently discharged. These ova (fig. 5)
measured about -r^th of an inch in diameter, and each con-
tained an embryo that, for some time after the extrusion of
the egg, made very evident movements. They have two
coats, an inner, faintly (concentrically) striated under pres-
sure, and an external, without markings. The contained
embryo is finely granular, and has a large pale nucleus ; its
various postures are seen in the outline (fig. 6). When an
ovum is ruptured between the glasses the contents spread
abroad as a vast number of dancing granules.

McIntosh, on the Gregariniform Parasite of Bor lasia. 41

These ova are altogether different from the ova of the
Borlasia itself, which have large capsules, each with a neck
ending in a long slender microscopic thread, the contents
undeveloped, and otherwise totally dissimilar, and deposited
in a large mass of consistent gelatinous substance, as first de-
scribed by E. Desor.* It is curious, however, that the para-
sitic ova should be provided with a similar coating when
extruded under pressure, and this coating is seen connecting
the ova within the body of the worm towards its posterior
end. The appearance of the contained embryo is much in
favour of its identity with the gregariniform bodies, though
as y£t I have not seen a perfect bond fide birth. These ova,
too, occurred in greatest plenty in August, whereas both
Desor and I have found the ova of the Borlasia deposited
towards the end of January. Kolliker does not specially
mention the ova of his G. Nemertis. Max Schultze mentions
and figures what he calls entire spheroidal forms, which
differ from the ova above mentioned in being simple cells
without thickened coats, and may or may not be in relation
to the gregariniform bodies.

The small bodies shown in fig. 4 were extruded with the
parasitic gregarinse in great numbers ; they were generally of
an ovoid or pyriform shape, a few being circular, and con-
tained many clear granules. The diameter of these structures
was about ToL(nj th of an inch, or rather more, whereas a speci-
men of a stray gregariniform parasite from the same annelid
measured -p^th of an inch ; therefore they do not seem to be
cysts formed after the conjunction of two gregarina?.

Occasionally one of the parasites is observed in a degene-
rating condition, forming an ovoid body in which the bent and
atrophied gregarina is scarcely distinguishable.

The large number of these gregariniform bodies, in some
examples of the Borlasia5, must give them a position of im-
portance— whether beneficial or prejudicial — in the economy
of the annelids.

# ‘Miiller’s Arckiv 5 for 1848, p. 511, pi. xviii, &c. I have not yet seen
the American version.

TRANSACTIONS OF THE ROYAL MICROSCOPICAL

SOCIETY.

On the Changes which accompany the Metamorphosis of the
Tadpole, in reference especially to the Respiratory and
Sanguiferous Systems. By W. U. Whitney, Esq.,
M.R.C.S., &c. &c.

(Read March 13th, 1867.)

In a paper read on the loth June, 1861, I had the honour
of submitting to the members of this Society a description of
the general sanguiferous system in the tadpole, the tracing of
which was rendered more complete and satisfactory with the
aid of the binocular microscope, at that time a recent inven-
tion.

Those investigations, and the subsequent ones, were made
with the admirable microscope possessed by my friend Mr.
Fitzgerald, and to his manipulative skill, not less than to the
goodness of his instrument, I am largely indebted.

A more extended inquiry has had the advantage (1) of
correcting an anatomical and physiological error into which I
had unconsciously fallen, the cause, nature, and correction of
which were explained in a communication to f The Intellec-
tual Observer 5 for May, 1863 ; and {2) of directing investi-
gation to the anatomical changes, in reference especially to
the respiratory and sanguiferous systems, which accompany
the metamorphosis of the tadpole from the form and functions
of the fish to the shape and habitudes of the reptile.

The fact that one creature possesses not less than three sets
of respiratory organs, two of which are successively developed
and then annihilated, could not fail to excite curiosity,
though the difficulty of tracing the steps of the process by
which these transitionary changes are accomplished appears to
have been generally felt. The writer of the article, “ Batra-
chia,” in the c Encyclopaedia Britannica,’ says, “ the change
or conversion from external to internal gills is not satisfacto-
rily described by physiological observers.” And this state-

vol. xv. e

44 Whitney, on the Metamorphosis of the Tadpole.

ment, it must be confessed, appears to be applicable even to
that accomplished and excellent authority, the late Dr.
Thomas Williams, author of the article “ Respiration ” in
the supplementary volume of ‘ Todd’s Encyclopaedia.’

The tadpole furnishes a remarkably interesting example of
gill structure and function, because the tadpole gills in tran-
situ exemplify in turn the simplest and the most elaborate
forms which these organs of aquatic respiration ever present.
As a general definition, a gill may be said to be a prolonga-
tion of surface externally , supplied with blood-vessels, and
adapted by its form and position for exposure to an aqueous
medium. On the other hand, a lung is a prolongation of
surface internally, forming a pulmonary cavity or sac adapted
to receive air.

The tadpole is furnished with two sets of gills, the external
and the internal, and these are intimately connected. The
vascular anatomy of this connection, upon which depends
the change whereby the respiratory function is transferred
from the outer to the inner gills, consequent on the atrophy
of the former, simultaneously with the development of the
latter organs, does not, as I have said, appear to be satisfac-
torily explained.

The first indication of the external gills is seen in the stage of
development represented in fig. 1,P1. Ill, in which a slight pro-
minence, seen just at the junction of the head with the body,
denotes the point at which the developing gill will protrude.
In a few hours more the prominence grows into a tubercular
like swelling, and we may even now begin to trace the motion
of the blood in these incipient gills. M. Milne Edwards, in
his large work on c Physiology,’ vol. ii, p. 206, quoting
Rusconi, says that it is only after birth that the blood begins
to circulate in the outer gills. But the writer has seen
examples in which these gills were protruded, with a visible
vigorous circulation in them, while the tadpole was still
within the capsule of the egg. When hatched, the form of
the gill is still more conspicuous, and in twenty-four hours
after birth (fig. 2) the comb shape of the organ and the
circulation within it are clearly exhibited. The outer or
rather outermost skin at this period is a thin but opaque
lamellated covering, which is gradually removed, and partly
by the mechanical action of the water, which seems to wash
away the thin lamellae of scurf-like epidermic scales from the
true skin beneath. Thus are revealed successively the trans-
parent coat of the eye, of the external gills, and, by degrees,
of the rest of the body. And thus the internal organs become
hourly more perceptible, until in the course of two or three

Whitney, on the Metamorphosis of the Tadpole. 45

weeks from date of birth, the entire skin, freed from those
pigmentary scales, attains its highest degree of transparency,
and heart, and gills, liver, intestines, and blood-vessels, are
seen in all the brilliancy of life and motion, and with as much
clearness as if we were looking at them through an integu-
ment of glass.

To return to the external gills. On the fourth or fifth day
after birth, and after the young tadpole is freed from the
remnants of the gelatinous mass he has been feeding on, and
has begun to live on vegetable diet, the external gills reach
their highest point of development. In this condition they
appear to the naked eye (fig. 3) on either side as a pair of
depending, slender filaments, delicately fringed. The length
of the filaments differs in different instances. The example
here figured was drawn from one of a batch of tadpoles, all
remarkable for the length to which these filaments had
grown, and equally remarkable, therefore, for their grace and
beauty. On examining with the microscope we find these
gills projected through an opening or fissure, situated on
either side below the head, corresponding to the operculum in
fishes. With the aid of the glass we resolve each filament,
with its fringe, into a transparent, comb-shaped case (fig. 4, a),
containing within it an arterial and venous system, to be
presently described. The fringe (to follow our simile) corre-
sponds exactly with the teeth of a comb, and, like them,
consists of processes (about six), all proceeding at right
angles from one side of the filament or back of the comb.
The filaments on either side are traceable inwards through
the fissure, where they become immediately and closely con-
nected with a bed or cluster of small digital-like processes,
some of which may be seen (at an early stage) just projecting
through the operculum fissure. These beds or tufts are, in
fact, the internal gills in their incipient, undeveloped state
(fig. 4, b).

The next perceptible change is a shortening of the
filaments, with a corresponding retraction of the processes,
which appear to be drawing inwards through the operculum.
At the end of the first week, under favorable circumstances
of temperature and light, the external gills are found to be
fast disappearing, while just prior to their complete removal
we may note a change in th e form of the tadpole. The con-
traction below the head (fig. 3) is obliterated by a filling out
in this direction, so that the tapering shape is exchanged for
a square or rather rounded form (fig. 5). At this stage
the body of the tadpole is daily becoming more transparent ;
but not until th e external gills have nearly disappeared is the

46 Whitney, on the Metamorphosis of the Tadpole.

skin sufficiently clear of pigment to afford us a glimpse of the
heart and other internal organs. The motion of the heart is
detectable, but its shape , at present, is indefinite, and the
blood-vessels are imperceptible. Hence the difficulty of
tracing the vascular connection of the outer gills with the
heart and inner gills ; for upon this “ the change or conver-
sion from external to internal gills ” evidently depends.

Hitherto I have not succeeded in obtaining, either by
artifice or chance, a tadpole at this stage sufficiently trans-
parent to exhibit to the eye this vascular connection.
Nevertheless, by a demonstration of the vascular system of
the internal gills, effected at a little later period, we may
obtain, I think, a satisfactory key to the comprehension of
that which exists, at the stage we are speaking of, in refer-
ence to the outer gills. But the reader will presently judge
for himself of the merits of this conclusion. The right external
gill shortens, is retracted, and disappears, sooner than the
left one. The gill is not simply retracted within the fissure,
but there is an absolute shrinking, withering, and ultimate
absorption of its substance. When this right gill has shrunk
within the fissure the latter is closed completely, so that the
gill chamber on that side is shut up. The remnant of the
gill, tucked in, as it were, is still perceptible, as represented
in fig. 6, c. In a few days this remnant is reduced to a bit of
shapeless substance, as seen in fig. 12, PI. IV, d , which, in a few
hours, is entirely removed. On the left side the process of re-
traction is slower. A small protrusion of left gill may be seen
for a day or two after the right one has disappeared ; and
when the left is absorbed the operculum on that side is found
to remain open as the aperture of exit for the water that
bathes the internal gills. The permanent form of the oper-
culum is seen in fig. 6. I have alluded to the changes of
form which the body of the tadpole undergoes during the
period in which the external gills shrink and disappear
(figs. 3 & 5). This change accompanies the first stage of
development in the second set of respiratory organs — the
internal gills. Fig. 4 represents the tufts of digit-like pro-
cesses composing the inner gills in their first stage, while the
outer gills are yet in full development. This figure is com-
posed chiefly from some dissected preparations made by my
friend Mr. Archer, after immersing the tadpole for a few days
in a weak solution of chromic acid. In this very early stage
the opacity of the skin renders it impossible to see the inci-
pient tufts composing the inner gills while the tadpole is alive;
hence the value of Mr. Archer’s preparations as exhibiting
th e form and position of the tufts at this period; but they

Whitney, on the Metamorphosis of the Tadpole. 47

cannot, of course, exhibit their vascularity. Fig. 6 represents
them with the digit-like processes larger and longer, while
the outer gills are shrinking and shortening.

Soon, however, we are able to find some specimens trans-
parent enough to show these tufts in what may be considered
their second stage of development. Fig. 12, PL IV, represents
the internal gill, with the c irculation in the tufts, as seen at this
more advanced period. Each digit contains a single blood-
vessel, which travels to the extremity on one side, loops at
the end, and returns along the other. With a half-inch glass
the blood-current in these loops is distinctly visible.

Tadpoles well fed and well supplied with fresh water,
plenty of light and air, and kept in a warm temperature, will
at this stage grow rapidly, while the skin now attains its
highest degree of transparency. At this middle period of the
metamorphosis the internal gills undergo a further develop-
ment, enlarge, and present, under the microscope, one of the
most brilliant and dazzling specimens of living vascularity
that can be seen. The change from the second stage of de-
velopment (fig. 12) to this, the perfect condition of the gill, is
highly interesting and beautiful. To trace and define dis-
tinctly the anatomical nature of this change is not easy ; but,
when discovered, our admiration is challenged by the beauti-
ful simplicity of the means employed.

Each cluster or tuft of the digit-like processes, seen in the
incipient condition of the inner gills (fig. 4) is divisible into
three double rows. In the second stage of their development
the three double rows are not only clearly apart, but have
between them red lines (fig. 12) indicating the trunks of blood-
vessels, which in this stage are in process of enlargement.
But on examining one of these gills a few days later, when
it has reached the third or period of complete development,
the eye is dazzled with a brilliant but confused display of
dancing globules ; and a maze of rapid crimson currents,
running in various directions, is seen in place of the cluster
or tuft of single loops of blood-vessel perceptible a day or two
before. It is clear that the gill has undergone a remarkable
change ; and if we get rid of the dazzle and confusion caused
by the maze of currents, by examining a dead tadpole (having
first removed the skin that covers the gill — or what is better
as a preliminary, having immersed the tadpole in chromic
acid according to Mr. Archer’s plan), we shall find that the
three double rows of digit-like processes with their simple
loops of blood-vessel, have become elaborated into three rows
of crests, each with a cauliflower-looking surface, as seen in
fig. 7, e. Thus we arrive at the form, but to understand the

48 Whitney, on the Metamorphosis of the Tadpole.

vascular system of the perfect gill we must return to the
living subject.

The brilliant but perplexing maze of blood-vessels which
the fully developed gill presents in the ordinary mode of
looking at it is, in fact, the vascular plexus of which the
crests are mainly composed. If we select a very transparent
tadpole, and examine a portion of the crest surface with a
■f or \ inch power, we find the blood-vessels assuming such
shapes as are represented in fig. 8. These shapes afford an
explanation of the change from tufts to crests , as far, at least,
as the vessels are concerned ; for it is easy to perceive that
when the blood and the impetus of the heart and arteries
are withdrawn from the external gills (by their destruction),
and expended upon the looped vessels of the digit-like pro-
cesses, how each simple loop becomes extended into the
tortuous and plexiform shapes observed, thus largely multi-
plying the vascular surface exposed to the aerating medium.
We have now to examine the course and connections of the
large trunks which convey the blood to and from the internal
gills.

It was not until it occurred to me to remove in the living
subject the integument in front of the gill that I succeeded
in obtaining a clear view of its vascular system. I had pre-
viously examined a large number of very transparent tadpoles
by simply looking through the skin, yet found it impossible
to obtain a clear and satisfactory view of the blood-vessels of
the inner gill. But by removing the integument in front of
the gill, so that the latter may be laid bare while the circula-
tion is still vigorous, a most brilliant and beautiful sight is
presented, and the observer is astonished that the little film
he has removed (albeit apparently quite transparent) effec-
tually obscured the simple and beautiful piece of mechanism
now before him. This operation can be performed without
pain. One drop of chloroform effectually destroys the sensi-
bility of the tadpole without damaging the force of the circu-
lation. I have seen the latter continue, with very little re-
duction of force, for two hours, under the influence of one
drop of chloroform. Should any sign of sensibility return, it
may be immediately quenched by touching the body with a
camel-hair brush dipped in the chloroform.

This dissection, to be successful, is a delicate and difficult
affair. Difficult, because, on the one hand, by incising ever
so little too deep, some of the vessels are wounded, and the
consequent haemorrhage empties the arteries and obscures
them ; while, on the other, if we do not remove enough of
the fine tissue between the skin and the vascular plexus, we

Whitney, on the Metamorphosis of the Tadpole. 49

cannot obtain a clear view of the latter. W ith much care
and pains and many trials, I cannot boast of having accom-
plished this task perfectly more than three or four times. On
these fortunate occasions, however, the vessels were com-
pletely unveiled and uninjured, and the entire plan of their
distribution and connections clearly displayed.

Each internal gill (by which expression I mean the entire
branchial organ on either side) may be said to consist of car-
tilaginous arches (fig. 13, PL IY, a), with a piece of additional
framework (b ) of a solidly triangular form, stretching beyond
the arches, and composed of semitransparent, gelatinous look-
ing material. These parts, forming the framework of the
organ, support upon their upper surface the three rows of
crests with their vascular network, and the main arterial and
venous trunks which lie parallel with and between them.
The vascular system displayed by laying bare (in the manner
already mentioned) the internal gill, is seen in fig. 13. The
three systemic arteries (a, b, c) arising, right and left, from
the truncus arteriosus, enter each gill on its cardiac side, and
then follow the course of the crests, lying in close proximity
to them. The upper of these branchial arteries runs along
on the outside of the upper crest ; and if the operator has
succeeded in clearly exposing the vessel without injury, he
will detect a branch (c) leaving the trunk and passing into
the network of the crest, whence a returning vessel ( d ) may
be traced carrying back the blood across the branchial
artery, and conveying it to another vessel lying close to and
taking the same course as the artery itself. Carrying the eye
along the latter vessel we find, at a short distance from the
first of these crest branches, a second (e), which leaves the
main trunk and enters the crest, whence a corresponding re-
turning vessel conveys the blood across the arterial trunk
into the vessel lying beside it, as in the former instance. A
succession of these branches (each taking a similar course)
may be traced from one end of the crest to the other. Put it
is now to be observed that the trunk from which these arte-
rial branches spring diminishes in size as it proceeds in its
course (like the gill artery in fishes), while the vessel run-
ning parallel to it and receiving the stream as it returns from
the crest enlarges in the same degree.* Thus, the artery or
afferent vessel which brings the blood to the gill is large at
its entrance, but gradually diminishes and dwindles to a

# The latter corresponds to the branchial vein in the gill of the fish ; only
the arrangement of vessels differs in the two cases, inasmuch as in the
tadpole the arterial and venous currents flow in the same direction, while in
the fish they travel in opposite directions.

50 Whitney, on the Metamorphosis of the Tadpole.

point at the opposite end of the crest ; while the venous or
efferent vessel, beginning as a mere radical, gradually en-
larges, and thus becomes the trunk that conveys the blood
out of the gill to its ultimate destination. Calling this vessel
the upper branchial vein as long as it remains in contact with
the gill, we subsequently change its name when it leaves the
gill and winds upwards for distribution to the head, and then
designate it the cephalic artery. The middle branchial artery
and vein proceed in like manner in connection with the
middle crest, and the lower artery and vein in connection,
with the lower crest. The middle and lower venous trunks ,
having reached the extremity of the crests, curve downwards
and inwards, and then leave the gill. The former trunk,
converging towards the sjnne, meets its fellow, and with it
forms the ventral aorta. The latter gives origin to the pul-
monary artery , and supplies also the integuments of the
neck.

We must now return to the external gills , for the sake of
offering an explanation of the vascular change which accom-
panies (and apparently causes) the shrinking and ultimate
disappearance of those organs, while, concurrently, we observe
the progressive development of the internal gills.

It is evident that the three arterial trunks arising from the
heart convey the blood to the outer gills for aeration during
the period that these organs are in full development and play.
It is evident, also, that during the same period the incipient
inner gills exist in the form of small tufts (fig. 4), which at a
little later period may, as I have said, be seen with the blood
traversing the single loop of blood-vessels contained in each of
the digit-like processes composing these tufts (fig. 12). As in
the tadpole we can distinctly see the pulmonary vessels in the
incipient lung of the future frog, so we cannot doubt that
this loop of blood-vessel (however small) exists in the gill tuft
in the first stage (fig. 4). I have already shown how the
loop becomes the crest , and how the latter is connected with
the large branchial vessels (page 49). For the same reason
that I infer the existence of the loop in the first stage of the
tuft, I infer also the existence of its vascular connection with
the main trunks or branchial vessels which are then con-
veying the blood to the outer gills ; and as, at a later period,
the blood-vessel loop is visible, so, at a little later period, the
vascular connection with the main trunks is also demon-
strable, Hence, if it be granted that the visible vascular
connection is but the enlarged development of the incipient
state, I think we may understand “ the change or conver-
sion from external to internal gills ” with the aid of the

Whitney, on the Metamorphosis of the Tadpole. 51

accompanying fig. 14. I would first observe that in the
post-mortem preparation (fig. 4) there is an obvious conti-
nuity of structure between the bed of inner tufts and the
outer gills. This observation prepares us for understanding
the vascular connection between them. In accordance, then,
with what soon becomes visible, we feel assured that the
three systemic vessels a, b, c, in their course to the outer
gills, run at the base of the three double rows into which the
inner gill-tufts are divided (fig. 14, in which a few tufts
in one row only are represented, for the sake of simplifi-
cation). As soon as the arteries arrive at the projecting
external gills, they become visible, are seen to run along on
one side, and supply each division of the gill with a branch,
which, having reached the extremity, forms a loop, by which
the blood returns on the opposite side by a corresponding
vein that travels parallel to the artery. With a frds power
several small communicating branches may be seen between
the vessels, perhaps as a proviso in case of accidental obstruc-
tion to the main current. Now, it follows from the previous
considerations that the branchial arteries, in their course to
the external gills, become connected with the gill-tufts of the
inner gills in the following manner : — Incipient twigs, given
off from the main trunk, and represented by the dotted lines
e,f, g, h, pass into the adjoining digit-like processes, each
forming a loop by which the current returns, and then, leav-
ing the digit, passes into the incipient upper branchial vein
(i), which is thus filled by the aggregate of these tributaries.
By close observation you may detect this vein in its early
stage (before the disappearance of the outer gills) as a thin red
line, taking the curved sweep of the future large vessel (the
cephalic artery ) into which it becomes developed. In like
manner the middle and lower branchial arteries must be con-
nected with the second and third double rows of tufts, whence
the blood returns to fill the incipient trunks which, at a later
stage, supply the remainder of the body.

Admitting this to be the correct explanation of the vascular
connection between the incipient inner tufts and the full-
grown outer gills, it follows that in proportion as the tufts
develope, and derive to themselves a correspondingly larger
quantity of blood, so the outer gills, being in the same degree
deprived of the latter, will have their function superseded,
while their delicate and feeble structure shrinks, and ulti-
mately disappears under the gradual abstraction of the vital
fluid. We may note the change of form with increase of
size in the tadpole’s body that accompany the simultaneous

52 Whitney, on the Metamorphosis of the Tadpole.

absorption of the externa t with the commencing development
of the internal gills (fig. 5).

With the disappearance of the outer gills, those vascular
changes by which the inner gills attain their full growth and
maturity are rapidly developed. These we have already
traced. It now remains to follow, as closely as we can, the
vascular arrangements by which the inner gills, having
accomplished their function as the tadpole’s second set of
respiratory organs, are, in their turn, to be removed and
succeeded by the true reptilian organs of respiration — the
lungs of the frog.

Each branchial artery, on entering the inner gill, communi-
cates directly with the corresponding branchial vein by a very
fine twig, which is, in fact, the radical of the venous trunk
(fig. 13, /). This trunk, it must be remembered, gradually
enlarges as it receives into it the newly aerated blood conveyed
from the crests by the cross branches. Now, if we examine
the gill in a very transparent subject at the period when the;
fore legs are about to protrude, or make a successful removal
of the integument covering it, we shall find that the fine
connecting twig has, in each instance, enlarged to a channel of
the same calibre as the artery itself (fig. 9, PI. III). Hence, in
the case of the upper pair of branchial vessels, more blood
begins to flow continuously from the gill artery into the efferent,
or cephalic trunk, without traversing the gill-crests ; in the
second pair, into the trunk which forms the aorta ; while in
the third a large part of the current passes at once into the
developing pulmonary artery and growing lungs. All this
time the blood is, of course, exposed to the aerating influence
of the water with which the gill is always bathed, but cannot
be so thoroughly aerated as when (in the early stage of tad-
pole life) the entire current traverses the fine plexus of which
the crests are composed. Thus, the blood begins to assume
the mixed quality which distinguishes creatures of the rep-
tilian type.

At a yet later period (when the legs are protruded) we find
an obvious diminution in the size of the inner gills, for the
proportion of blood which then flows continuously into the
systemic circulation and pulmonary arteries hourly increases,
while that which yet finds its way into the crests diminishes
in the same ratio. With the advent of the extremities the
creature instinctively seeks to breathe in air rather than in
water ; and so little of real gill function remains that, if tad-
poles at this stage are confined in a bottle of water, they are
very apt to die from drowning unless a piece of cork be

58

Whitney, on the Metamorphosis of the Tadpole.

placed on the water, whereon the tadpole can mount and
breathe the air.

Curious and beautiful is the final stage of the metamor-
phosis, when the waning tadpole and incipient frog coexist,
and are actually seen together in the same subject (fig. 10).
The dwindling gills and the shrinking tail — the last remnants
of the tadpole form — are yet seen, in company with the
coloured, spotted skin, the newly formed and slender legs,
the flat head, the wide and toothless mouth, and the crouching
attitude of the all but perfect reptile.*

By the process now described, the three systemic arteries
(fig. 13) become continuous with the corresponding efferent
trunks that convey the blood for distribution through the
body, while, simultaneously, the vital fluid is being abstracted
from the special trunks belonging to the gill and its vascular
crests. These, with the gill structure connected with and
dependent upon them, being thus deprived of their blood,
shrink, become absorbed, and so disappear. Such appears
to be the beautifully simple mechanism by which the transi-
tion in the type of the respiratory function from fish to
reptile is accomplished.

We have now to consider the third set of respiratory
organs, the lungs. When examined in the young, newly
formed frog, they are found to have arrived at organic and
functional completeness ; but they coexist (in an incipient
form) with the gills of the tadpole , and pass through their
gradations of development simultaneously with those phases
of maturity, decline, and decay, in the gill organs, whicli have
been described. If we take a tadpole a few days old, when
the outer gills are fully developed, and immerse it for another
few days in a weak solution of chromic acid (Mr. Archer’s
method), we may, by placing the tadpole under a dissecting
microscope, and with the aid of a needle and camel-hair
brush, then remove the integuments, disclose the tufts of the
inner gills, and by carefully getting rid of a prominent roll of
intestine that occupies the upper part of the abdomen, succeed
in revealing the incipient lungs. These are situated behind
the gut and close to the spine, and appear as a pair of minute
tubular sacs, united at their upper and open extremities
(fig. 4). It is much easier to describe than to perform this
little operation ; but that it has been achieved is amply proved

* With the loss of the inner gill, the teeth and fringed lip possessed by the
tadpole also disappear, because the labial artery, whicli supplies these organs
with blood, has its origin in the gill, and proceeds directly upwards to the
mouth. Simultaneously, therefore, with the loss of the gill, the oral ap-
pendages proper to the fish are also removed.

54 Whitney, on the Metamorphosis of the Tadpole.

by the several very interesting preparations which my friend
Mr. Archer has successfully made. The chromic acid renders
the tissues friable, so that they can be readily peeled away.

During the period of the tadpole’s transparency a part of
each lung is usually perceptible, and may be seen, on looking
through either side of the abdomen, as a transparent, saccu-
lated bladder of air. On one occasion I met with an example
in which the tadpole exhibited the lungs, through the back,
in a very beautiful and unusual manner. They were lying
side by side, close to the spine, and, to the naked eye, looked
like a double row of brilliant globules, glistening like quick-
silver. (Fig. 11 represents them as seen under the micro-
scope.) This singular display was due to a temporary shifting
of the bowels, whereby the lungs were distinctly brought
into view ; for on looking at the same tadpole on the follow-
ing day I found that the bowels had changed their position,
and then the lungs were concealed. Fig. 7 represents the
lungs in a tadj^ole at about the middle period of the meta-
morphosis, showing the progressive development and elonga-
tion of the tubular sacs.

When the last vestiges of the tadpole form — the remnants
of the tail and gills — have disappeared, the lungs, though
small and extremely delicate, are found to present a perfect
miniature of what they afterwards become in the full-grown
frog. Of all the sights to be seen in tracing the metamor-
phosis of the tadpole, the most splendid is that of the crimson
gill with its vital current in vigorous circulation. Next to
that, as something beautiful to see, is the appearance presented
by the lung of the young frog with its circulation in vigorous
movement. To obtain this sight the lungs should be full of
air, and the heart vigorously beating. These conditions,
however, are seldom easy to attain. Put the young frog into
a wine-glass, and drop upon him a single drop of chloroform.
This suffices to extinguish sensibility. Then lay him on the
back on a piece of cork, and fix him with small pins passed
through the web of each foot. Remove the skin of the
abdomen with a fine pair of sharp scissors and forceps. Turn
aside the intestines from the left side, and thus expose the left
lung, which may now be seen as a glistening, transparent
sac, containing air-bubbles. With a fine camel-hair pencil
the lung may now be turned out, so as to enable the operator
to see a large part of it by transmitted light. Unpin the frog
and place him on a slip of glass, and then transmit the light
through the everted portion of lung. Remember that the
lung is very elastic, and is emptied and collapsed by very
slight pressure. Therefore, to succeed with this experiment.

Ray Lankester, on the Tooth in Ziphius Sower biensis. 55

the lung should be touched as little as possible, and in the
lightest manner, with the brush. If the heart is acting feebly
you will see simply a transparent sac, shaped according to
the quantity of air-bubbles it may happen to contain, but void
of red vascularity and circulation, as in the left lung of fig. 15.
But should the operator succeed in getting the lung well
placed, full of air, and have the heart still beating vigorously,
he will see before him a brilliant picture of crimson network,
alive with the dance and dazzle of blood-globules, in rapid
chase of one another through this delicate and living lacework
which lines the chamber of the lung (fig. 15). The trunk
of the pulmonary artery is conspicuous on the one side as the
channel which brings the blood to the lung, and the ramifi-
cations of which constitute the fine network aforesaid, while
the pulmonary vein on the other side returns the aerated
blood to the heart. The internal surface of the lung becomes,
in the older frog, developed into numerous shallow cells, the
boundaries of which correspond to the polygonal facets pre-
sented by the external surface.

Fig. 16 is the drawing of a dissection made to exhibit the
trunks of the systemic arteries in the frog, with the origins of
the pulmonary arteries and the course of the pulmonary
veins, in the full-grown reptile.

Permit me, in conclusion, to thank you for the gracious
and liberal manner in which you have enabled me to present
the results of my humble labours on this interesting subject
to the members of this society.

On the Structure of the Tooth in Ziphius Sowerbiensis
(Micropteron Sowerbiensis, Eschricht), and on some
Fossil Cetacean Teeth. By E. Ray Lankester,
F.R.M.S. of Christ Church, Oxford.

(Read May 8th, 1867.)

If it be true that “ differences in structural arrangement
which exist without our being able to see why they should
exist possess a morphological value which rises in direct
proportion with their physiological obscurity,”* the teeth of
the Ziphioid Cetaceans have a very considerable claim on the
interest and attention of zoologists. The “ reason why ” a
Cetacean should have two powerful teeth in its lower jaw—
apparently incapable of biting, or curved over the top of its

* Professor Rolleston, ‘Trans. Zool. Society,’ vol. v. part 4, p. 311.

56 Ray Lankester, on the Tooth in Ziphius Soive'rbiensis.

snout so as to prevent the opening of the mouth beyond a
very limited extent, as in Ziphius ( Dolichodon ) Layardi ,
lately described by Dr. Gray, is certainly at present ob-
scure ; still more .difficult is the explanation if, as it appears,
the males only have these massive teeth. That these teeth,
or rather one tooth of a certain Ziphioid, and probably also
those of others, present marked differences in structural
arrangement, distinguishing them from the teeth of other
Cetacea, I hope to show in the following pages.

As far as I have been able to ascertain from the writings
of Yan Beneden, Gervais, Duvernoy, and others, no descrip-
tion has yet been published of the dental tissues of any one
of the Rhynchoceti, excepting a brief notice of the small
pointed denticles in a species of Hyperoodon, given by Pro-
fessor Owen* in his ‘ Odontography,’ from which it does not
appear that there is any close analogy between Hyperoodon
and Ziphius ( Micropteron ) in regard to the teeth ; and, in-
deed, they have a very different position and time of appear-
ance in the two forms.

The synonymy of genera and species in the Rhynchoceti
is likely to cause some confusion, and I shall therefore make
use of the generic and specific terms approved by Professor
Huxley in a very concise memoir on a fossil Ziphius, pub-
lished in the e Quarterly J ournal of the Geological Society,’
1864, p. 395.

The lower jaw and the larger part of the skull of the male
specimen of the rare species Ziphius ( Micropteron ) Sower bi-
ensis, which was thrown ashore in Elginshire in 1800, and
was engraved in Sowerby’s ‘British Miscellany,’ 1806, p. 1,
pi. i, is preserved in the Oxford University Museum, having
been purchased by Dr. Buckland at the sale of Sowerby’s
museum, and presented by him to the Anatomical Museum
of Christchurch, whence it was transferred with the rest of
the collection to the University building.

I have been allowed to figure and describe the microscopic
and other sections which have been made from the right lower-
jaw tooth of this specimen, and Mr. Tuffen West has also had
one of three sections entrusted to him for comparison with my
drawings whilst engaged in the work of engraving them.

A history of the Oxford specimen, as also a full biblio-
graphy of the various memoirs which have appeared upon
the anatomical and zoological relations of this animal, will he
found in the ‘ British Museum Catalogue of Seals and
Whales,’ 1866, p. 350.

* See also Yrolik’s figures in his Memoir on Hyperoodon. Natural His-
tory Society, Haarlem, 1848.

Ray Lankester, on the Tooth in Ziphius Sowerbiensis. 57

The lower jaw exhibits two large teeth very deeply im-
planted in their sockets, of a curved or somewhat claw-like
form, very much compressed laterally, and fixed so that the
curve is directed backwards instead of forwards, as is usual
with teeth having the general form of canines.

External characters of the tooth. — In Pl. V, fig. 1, one of
the teeth is drawn of the natural size ; the line a, b} indicates
the direction of the horizontal line of the alveolus when the
tooth is in its natural position in the jaw. The lateral com-
pression of the tooth is seen from fig. 3, which is half of a
transverse section taken at a. The whole exterior surface,
with the exception of the small conical crown, is very rough,
irregular, and knotted, having a somewhat resinous lustre
and a yellowish colour. This external tissue is, as in other
teeth, “ cement.” The small conical crown which seems to
rise out of the cement like a nipple is in one of the two
teeth very sharply marked off from the rest of the tooth by
the presence of a crack between it and the yellow nodu-
liferous cement. Its surface has the peculiar vitreous lustre
characteristic of dentine, and is white. That tooth which has
not been cut is heavy for its size, and appears to be solid and
compact throughout.*

Longitudinal section of the tooth. — In PI. V, fig. 2, the
longitudinal section of the tooth is drawn to a certain extent
diagrammatically, the small remnant of a pulp-cavity being
introduced from the opposite half of the section. The true
nature of the various layers exhibited was ascertained by
microscopical examination of three cross sections cut at about
the point a , and one sixth of an inch lower (PI. V, fig. 1,
and PI. Y, fig. 3) from the other half of the specimen.

The great thickness of cement is very remarkable (c),
completely enveloping the small cap of true dentine (d),
with the exception of its projecting point. The cement
forms the outer wall of all the rest of the tooth, being con-
tinued round the calcified pulp-cavity, into which it projects
very largely in a curiously irregular manner in some places.

The small cap of dentine (d) is very clearly marked off
from the rest of the tooth in the section by the bri ght
vitreous lustre it has acquired in the polishing to which the
specimen has been submitted. This small conical cap, hardly
more than half an inch in length, appears to be all the true
dentine developed in the tooth, with the exception of a very
thin layer extending between the cement and calcified pulp
about halfway down the tooth, which is, however, for the
most part composed of a structureless “ globular ” mass of
* Sowerby in his description characterises the teeth as “honey.”

58 Ray Lankester, on the Tooth in Zipkius Sowerbiensis.

calcareous material. The exceedingly small development of
dentine is one of the most noticeable peculiarities presented
by this tooth. The pulp-cavity is throughout occupied by a
very dense vascular form of osteo-dentine, excepting a small
elongated space which is left within the terminal cap of true
dentine. This position for a residual pulp- cavity is, I be-
lieve, quite unprecedented ; in other Cetacean teeth, in the
tusks of Trichechus and Sirenia, which have their pulp-
cavity to a large extent occupied by osteo-dentine, the re-
sidual pulp-cavity is always at the base instead of at the
crown of the tooth. To the naked eye the osteo-dentine
filling the pulp-cavity in the Micropteron tooth presents in
the longitudinal section a cracked irregular structure.
Fissures run longitudinally through parts of the material,
and ridges of a lighter colour and denser appearance than
the surrounding parts traverse the surface in irregularly
longitudinal and oblique directions. The fissures appear to
be caused by the canals of the osteo-dentine ; the denser
ridges by the lacunar but hard 66 globular ” matter into which
the tissue surrounding the canals is in many parts converted.
The points to be noted in the naked-eye appearances of the
tooth and its section are — the minute size of the conical cap
of dentine, its being imbedded in the surrounding cement,
the thickness and irregular disposition of the cement, the
position of the residual pulp-cavity, and the excessive de-
velopment of dense globular matter in the dentine and also
in the osteo-dentine filling the pulp-cavity.

Microscopic characters of the dental tissues. — Plate V ) ?
fig. 1, represents a portion of a transverse section of the
tooth from near a (PL V, fig. 2), prepared by Mr. Topping,
whilst PI. VI, fig. 2, is a smaller portion of a section taken a
very little lower down. The most striking feature in both is
the very large development of opaque, apparently structure-
less material separating the cement from the dentine of the
tooth.* It is very sharply marked off from the cement, but
on the other side shades off into the dentine (or perhaps
osteo-dentine in some parts of the tooth), of which it is really
but a part. Both this globular matter and the cement pre-
sent large circular and longitudinal fissures which were
vascular canals. In fig. 1 the dentine is seen to merge into
the osteo-dentine surrounding the two circular canals ; in
fig. 2 it is cut off from the osteo-dentine by a fissure and
deposits of globular matter, and has a very much more

* The dentine of the narwhal’s tusk ( Monodon ) exhibits this same opacity
— due to imperfect calcification — in a striking manner. It is also observ-
able in many other large teeth, but less markedly.

Kay Lankester, on the Tooth in Ziphius Sower biensis. 59

limited development, the section in fig. 2 being taken further
away from the terminal cap of dentine than that in fig. 1 .

Cement (PI. VI, fig. 3). — The lacunae of the cement are
disposed in regular concentric series (figs. 1, 2, c ), abound-
ing more along certain planes than others, thus giving
the structure a banded character. At various parts of the
periphery the formation of nodular protuberances gives an
irregular character to their arrangement. They are rounded
and very irregular in form, with but small though very
numerous diverging canaliculi : their size is very great,
varying from the -5-^-oth to the t A 0th of an inch and less.
They are less numerous than in the cachalot or porpoise,
and of larger size. The ultimate ramuscules of the canaliculi
could be seen, by some care in the lighting and focussing of
the object, to enclose square or polygonal spaces of struc-
tureless material of an average diameter of ■5-fr1T5-th of an
inch. In some parts the canaliculi united to form small,
much elongated lacunae (fig. 3, «), this variation in the
structure having apparently some connection with the pro-
duction of the cement into a surface-ridge or tuberosity.

Globular matter and dentine. — The parts of the opaque
stratum of globular matter nearest the cement presented no
structure excepting an indistinct botryoidal character, visible
with a low magnifying power. This was more distinct nearer
the dentine (fig. 1, 2, g), where variations in the opacity
of the layer disclosed such a disposition. The amorphous
matter at length shades off into the dentine, as seen in Plate VI,
fig. 4, numerous distinct, minute, “ interglobular spaces ” be-
coming more and more distinct as one recedes from the opaque
stratum and their number diminishes. The “ interglobular
spaces,” sometimes known as “ dentinal cells ” (not of Owen),
have no very definite form, but are simply minute transverse
lacunse intercepting the light, and by their superabundance
contributing to the opacity of the amorphous stratum of
globular matter. They had an average breadth of ToVoth
of an inch. The dentinal tubes have nothing remarkable in
their character. They are rather coarse, though finer than
in many Cetacean teeth, or than those of the walrus tusk,
and communicate frequently with one another near their
peripheral origin or rather emersion from the opaque stratum.

Osteo-dentine and globular matter. — The osteo-dentine
and the globular matter which in many cases surround the
periphery of an osteo-dentinal canal or cavity and its tubules,
in intimate character do not differ materially from the similar
parts just described. The canals of the osteo-dentine are
numerous and large, appearing in section as circular, fusi-

vol. xv. f

60 Ray Lankester, on the Tooth in Ziphius Sowerbiensis .

form, or much elongated, narrow cavities. The dentinal
tubules of one canal do not anastomose to any large extent
with those of other neighbouring canals, in many cases a wall
of opaque globular matter enclosing each. The tubules of
some of the osteo-dentinal canals are very few in number,
and have an irregular tortuous distribution, the canal, when
in section in such cases, resembling a very large multiramose
bone lacuna.

Comparison with other teeth. — In no other Cetacean teeth
is the dentine developed to so small an extent, and the cement
and osteo-dentine so largely concerned, in forming the mass of
the tooth. In the large conoid teeth of the cachalot the
dentine occupies a very much greater space in the tooth, the
osteo-dentine is sparsely developed, and a certain amount of
basal pulp-cavity is left, while the cement, though forming
a thick layer on the tooth, is comparatively small in amount.
In Hyperoddon the small pointed teeth are stated by Professor
Owen to be tipped with enamel, which does not appear to be
the case in Micropteron. In the Porpoises and Grampuses
the dentine has a large development, and osteo-dentine, when
present, bears but a very small proportion to it.

Purpose of the teeth. — The teeth of Micropteron are not worn
at the crown, and are obviously not used for biting, since they
are not opposed by any part of the upper jaw. They are said to
be sexual characteristics, Eschricht considering the toothless
Delphinus micropterus (Cuvier) to be the female of the bident
Micropteron Sowerbiensis * These teeth, then, obviously have
their true function aborted, degraded from the class of “ func-
tions of animal life ” to that of “ functions of vegetable life
and with this we may expect a corresponding degradation in
structure, resulting in the production of a tooth of less
specialised character, and less differentiated from the rudi-
mentary structure of a developing tooth. This, I think, can
be shown to be the case with the tooth described above.
Cement is not a structure belonging specially to teeth ; it is
merely bone such as exists throughout the body. Osteo-
dentine is a less differentiated structure than true dentine,
being formed by a conversion of the substance of the pulp
instead of at its periphery, and retaining certain elements of
the pulp in its canals and cavities ; moreover osteo-dentine is
developed in many teeth ( e . g. human) only as the result of
age and decrepitude, or as a pathological product ; in others,

* The female stranded at Ostend is said to have had “a few” small
denticles concealed in the anterior part of the lower jaw. It is not at all
improbable that the male, when young, has many teeth, one only of which on
each side is developed.

Ray Lankester, on the Tooth in Ziphius Sowerbiensis. 61

which are of large size ( e . g. the tusks of the walrus), merely
as a packing or strengthening for the hollow pulp-cavity.
Osteo-dentine is therefore of low physiological importance.
Dentine and enamel are the special tissues of the tooth, pre-
sent the greatest amount of differentiation, and are formed
under the most special conditions, and probably with the
greatest expenditure of force.

The tooth of Micropteron has only the small terminal cap
formed of this special tooth structure, resembling in this a
foetal human tooth, and, indeed, were such a tooth, minus its
enamel, arrested in its development at this stage, its vascular
pulp allowed to convert itself into osteo-dentine, and the sur-
rounding tooth sac subsequently ossified into cement, we should
have a miniature representative of the Micropteron tooth.

The large development of opaque globular matter in the
dentine and osteo-dentine of the Micropteron tooth is also
significant of low organisation. The opacity is caused by
the large number of interspaces left between globular and
botryoidal masses of calcareous salts deposited in the forma-
tion of the tooth, that is to say, it is due to imperfect calcifi-
cation. This appearance is frequent in human embryonic
teeth,* and is occasionally to be met with to a small extent in
those of the adult and in very many mammalian teeth. It is,
however, in the human subject corrected as development pro-
ceeds, the interspaces being filled up. In Micropteron it is
not so ; the rudimentary calcification is allowed to persist.

For these reasons, then, I think it may be urged that we
have in the teeth of Micropteron Sowerbiensis a rudimentary
structure corresponding with a degraded function.

Teeth of other recent Ziphioids ( Dolichodon ). — I had the
good fortune to see the skull of the Ziphius ( Dolichodon )
Layardi described by Dr. Gray, at the British Museum,
before it was packed to be returned to Cape Town, whence
it came. The great curved teeth, one in each ramus of the
lower jaw, as in Micropteron , are even more laterally com-
pressed and flattened than in that genus; their length exceeded
a foot, while their width was about two inches. The exterior
surface was smoother than in the Oxford Cetacean, but of the
same yellow colour characteristic of cement. I looked
anxiously for a projecting tip of dentine as in Micropteron ,
and at the crown of each tooth, on the inner side, was a very
small nob or nipple of brighter appearance than the sur-
rounding surface, evidently corresponding with the dentinal
cap of Micropteron . This protuberance is I find noticed by
Dr. Gray in his catalogue of seals and whales, where a small
figure of this very remarkable skull is given. Though, in the

* Tomes.

62 Ray Lankester, on the Tooth in Ziphius Sowerbi&nsis.

absence of any sections, certainty is impossible, there can, I
think, be little doubt that the structure of the tooth of
Layard’s Ziphius agrees with that of Sowerby’s, and assuredly
the small projecting caps of dentine are identical. Some
zoologists are inclined to regard the strange overlapping
teeth of j Dolichodon Layardi as deformities. Dr. Gray, how-
ever, does not incline to this opinion. The two teeth are
almost exactly alike, and very regular and definite in form,
and certainly have not the aspect of abnormal growths.
Whether deformities or not, their function is in the highest
degree obscure ; and, supposing that they have grown to an
abnormal size, their essential composition and form is pro-
bably unaltered.

Berardius. The figures given of the teeth of the tetrodont
Ziphioid Berardius by Duvernoy appear to indicate a nipple-
shaped termination to a broad flattened tooth— as in Micro -
pteron*

A second male specimen of Sowerby’s Micropteron has
recently been cast ashore in Ireland, and the skull is pre-
served. It is desirable that the teeth of these specimens
should be examined, as also those of the other ziphioids in
various museums, both by simple and microscopic sections.

Fossil ziphioid teeth from the Red Crag. The woodcut,
fig. 1, represents a remarkable compressed claw-like body

Reduced to one half the natural size.

from the Red Crag ; three other specimens similar to it are in

* Since this paper was read I have seen the first part of a paper by M.
Fischer in the ‘ Nouvelles Archives du Museum/ 1867/ 3rd vol., “ Oil the
Cetaceans of the genus Ziphius” He does not appear to have examined
the structure of the tooth in any of the species he quotes, but I hope may
be induced now to ascertain if the structure here described is common to
the Ziphioids in his charge.

F/G-' 2.

Ray Lankester, on the Tooth in Ziphius Sower biensis. 63

the collection of Mr. Whincop, of Woodbridge. When cut
longitudinally an appearance like that of “ pudding-stone ” (a
simile used by Cuvier when describing the osteo-dentine of
the walrus) was shown, accompanied with numerous longi-
tudinal fissures. In PI. VI, fig. 4, a portion of this same body
cur, transversely and mounted for microscopic examination is
drawn. Figs. 5 and 6 represent two of the multiramose
canals more highly magnified. No other structure than these
bodies, and a homogeneous iron-stained matrix, could be made
out. The claw-like fossil is very probably the osteo-dentinal
core of a tooth of some one of the Rhynchoceti, the rostra of
which are so abundant in the crag.

Reduced to one half the natural size.

The structure of the ziphioid tooth, as ascertained from
the Micropteron Sowerbiensis, throws some light on the nature
of the tooth called Balanodon, by Professor Owen. In a paper
published in the f Quarterly Journal of the Geological Society/
1865, p. 231, I mentioned that Professor Van Beneden had
obtained specimens from the Antwerp crag, which he identi-
fies with our crag Balcenodon, and considers as ziphioid. The
Balcenodon teeth, such as that drawn in fig. 2, are very much

64 Sheppard, on Colour in Organised Substances.

rolled and truncated at each end. In section they show a
core of osteo-dentine with very thick walls of cement. They
are much rounder and bulkier teeth than those of the recent
Micropteron. Some specimens show anteriorly fragments of
a brighter denser substance, which I believe are the remains
of the dentinal cap or nipple characteristic of ziphioid teeth.
The infiltration of mineral matter in varying quantities into
the differently constituted tissues of the tooth would readily
cause their separation, and the double rolling and deposi-
tion to which these crag mammalian remains have for
the most part been subjected, would be very efficient in
breaking off the small tip of the tooth. Figs. 3 and 4 represent
of half the natural size two very large Cetacean teeth which I
obtained some time since from the Red Crag. The first
(fig. 3) is in section, and appears to have preserved a small
cap of dentine surmounting the osteo-dentine and cement,
which form the bulk of this very large tooth.* Fig. 4 is
probably not the tooth of a ziphioid at all, but is remarkable
for its large size.

On an Example of the Production of a Colour possessing
Remarkable Qualities by the Action of Monads (or
some other Microscopic Organism ) upon Organised Sub-
stances. By J. B. Sheppard, M.R.C.S.E.

(Communicated by the Rev. J. B. Reade, F.R.S., F.R.M.S., &c.)

(Read May 8th, 1867.)

I will relate, as shortly as I can, the steps by which I
became acquainted with the properties of the coloured liquid
in the “ thousand-grain bottle. ”f The history is as follows :
— On April 19th I went with two archaeological friends for a
long ramble through West Kent. Our route lay through
that district where the greensand crops out from under the
chalk escarpment between Ashford and Maidstone. About

* The chief interest of this specimen is in the preservation on its surface
of a large amount of the fine sandy deposit in which it wras imbedded, pre-
viously to its deposition in the Red Crag-, it being like all the other Rhynchoceti ,
Carcharodons, &c.,of theRed Crag — already a fossil when the Red Crag sea and
mollusca were existing. This fact has been unaccountably overlooked by
some geologists, who wish to show that the Red and Coralline Crag were
contemporaneous , or nearly so, with the Lower and Middle Antwerp Crags,
where similar Cetacean remains occur in an unrolled condition, the Cetacea
&c., having lived during that period, not during the Red Crag.

f Shown at the Soiree of the Royal Microscopical Society, by the Rev.
J. B. Reade, April 24th.

65

Sheppard, on Colour in Organised, Substances.

midway we came to a clear spring rising in a rocky basin
(Kentish rag, carbonate of lime), and on all the submerged
stones in the basin there was a dark olive-brown coating,
covering every surface with a velvet-like film, and thick
enough to be scraped ofl* in an unbroken sheet — just such a
coating, in fact, as promised oscillatorise and diatoms.

My companions being archaeologists, and not microscopists,
in deference to their tastes I had forborne to take any appa-
ratus or receivers for collections, having on other occasions
bored them by wasting time, as they thought, about pond-
edges and spring-heads. Having no bottles, I begged from
my friend a piece of paper — a part of the wrapper of his
sandwiches — and to this piece of paper, greasy and glazed
with some sort of size, is partly due the result which I am
about to communicate.

The specimen in the paper was placed in an india-rubber
tobacco pouch, and remained undisturbed for twenty-four
hours before I opened the parcel to separate a piece for mi-
croscopical examination. As soon as the parcel was taken
from the pouch, I noticed that the paper was stained here
and there with hues of red, blue, and purple, and (the paper
being removed) in the wet mass within I saw small clots of
red jelly, exactly counterfeiting recently coagulated blood.
I selected a clot and pat it on a slide, whilst the rest of the
mass was laid in a glass of clear water. This mass consisted
of interwoven oscillatorise and other confervoidese, with na-
vicula-shaped diatoms pervading the texture, and, excepting
the clots, presenting nothing that is not to be found on the
stones of every wall. The specimen on the slide was remark-
able. The colour, before placing the glass on the stage, was
opaque red, looking like a small quantity of vermilion mixed
with water ; but when held up to the light the red disap-
peared, and a pale transparent blue took its place.

Under the microscope (1 -inch, “ B”) the clot appeared of
a pale blueish-grey, quite transparent and structureless ; but
entangled in this now grey-looking jelly were several bodies
which I took to be ova. In form they were pointed-oval —
almost kite-shaped — buff as to colour, and moderately opaque.
Each example contained a small collection of reddish and
brownish cells, with one, or at most two, larger spherical,
colourless globules — perhaps vacuoles.

After examining two or three of the clots, and finding in
each some of these ova, I concluded that in some manner
they contributed to the formation of the red colour ; and from
farther experience I feel certain that but for the dirty piece
of paper and these bodies this interesting subject would never

66 Sheppard, on Colour in Organised Substances.

have presented itself to me. I may mention that these egg-
shaped bodies, surrounded by a gelatinous or albuminous
envelope, are distinguished by the possession of an undoubt-
edly flexible, easily ruptured coat, and by a general dotting
all over the surface, when seen by oblique light. But after
the first day these bodies were absent, and with them the
clots and the colour, this latter being entirely transferred to
the water in which the mass was placed. In a note of the
27th ult. you say that the question, “Whence the colour?”
is in every mouth. I have not been inattentive to this point,
as you know. Having no doubt that the colour was due to
the presence of some substance dissolved in the liquid, and
not to any organisms suspended in it, I was anxious to ascer-
tain what the liquid did hold in solution. Boiled in a test-
tube, the colour faded, and a flocculent precipitate was pro-
duced. Bichloride of mercury destroyed the colour and
procured the precipitate, as also did nitric acid. From these
tests, of which you were an eye-witness, it was certain that
albumen was present ; and the disappearance of the colour
when this albumen was thus artificially coagulated seemed to
indicate that soluble albumen was a necessary ingredient in
the process. We have not far to look for the source of this
albumen, for the mass abounded with slimy clots (limpid,
changing to red), each of which enveloped a number of the
above ova.

The “thousand-grain” bottle exhibited at the microscopical
soiree contained the solution of these albuminous clots, and
the colours, both of the clots and the solution, seemed from
my observations to be inseparable from the agency of the
monads and the oscellatoriae of the eonfervoid mass. Hence,
in my first note (April 22), I expressed strongly the opinion
that “ the colour is due to some form of albumen under the
influence of some form of life ; as long as the life continues,
the phenomena of the colour continue, and when it ceases
they cease.”

This was the upshot of my first journey, and, to make my
story continuous, I will here insert your letter on the subject,
which describes some facts observed by yourself, and also the
very interesting spectroscope phenomena, communicated by
Messrs. Sorby and Browning.

“ Bishopsbourne Rectory, Canterbury ;
“ April 27 , 1867.

“ My dear Sheppard, — Accept my best thanks for your
interesting account of the coloured solution. It was carefully
examined by my friends in London at our Microscopical

Sheppard, on Colour in Organised Substances. 67

Soiree, and was very naturally supposed to be a new solution,
either of iodine, aniline, or some curious chemical compound
resembling the 4 chameleon mineral.’ But the beautiful
lambent blue by transmitted light, and the deep carnelian
red by reflected light, was an effect they were not prepared
for. When I gave it a name, perhaps for the amusement of
our lady visitors, who were fascinated with the play of colour,
a name withal, perhaps, not very far beside the mark, and
called it 4 polychromatic infusorial water,’ a clue was given to
its origin, though its nature remained a mystery. You are,
therefore, earnestly requested to continue your researches till
you can 4 render a reason.’ I stated that at present you con-
sider it to be some form of albumen connected with some form
of life ; and I gave the substance of your story to those who
had not an opportunity of reading it.

44 Upon examining the solution with the spectroscope.
Browning said that it gave the most curious spectrum he
had ever seen, and Sorby highly values it as being the only blue
solution in his class C (of which the blood spectrum is the
type) that gives a dark band in the red rays ; and he wishes
to have a sample of the confervoid mass for further experi-
ment. You may therefore be congratulated upon having
recorded a new fact of special interest to microscopists. In
addition to your statement I was able to add, from my own
examination of the solution, that the process of filtering left
a delicate pink stain upon the paper, without materially
weakening the colour or colours of the solution ; and on
evaporating a filtered drop to dryness, and examining it
under a high power on a dark ground, I was convinced that
the life you speak of is due to the infinitesimally minute
monad . This supposition was, curiously enough, confirmed
yesterday at Browning’s, when we witnessed the voluntary
motion of these atoms, 4 nature’s invisible police,’ under the
spectroscope.

44 But the question was still in every mouth, 4 Whence the
colour?’ Infusoria, which are themselves coloured, are
known and described by all observers. Ehrenberg, Carpenter,
Hogg, &c., describe the red protococcus, or snow plant, the
Palmella cruenta , 4 of the colour and general appearance of
coagulated blood,’ the Haematococcus sanguineus , and the
Astasia hamatodes. The latter, Hogg says, 4 is a kind of
crimson-coloured animalcule, -g-rs-th of an inchin length, that
exist in enormous numbers, and give the waters in which
they live the appearance of their bodies.’ But these do not
give a permanent stain to the water, nor is there any recorded
instance of the marvellous variety of colour which your solu-

68 Sheppard, on Colour in Organised Substances.

lion possesses. It happens, however, curiously enough, that
in a subsequent conversation with Sorby, I learnt that a
German naturalist has just lately discovered a monochromatic
solution, ‘ the result of decaying algae,’ and of this Sorby
promises to send me the particulars.

“ Your solution, at all events, is new both to him and to
English observers generally ; and we hope that your second
visit to the scene of action will enable you to prepare a special
communication for our next microscopical meeting.

“ Believe, &c.,

“ J. 13. Reade.”

A week after my first visit I again visited the spring for a
farther supply of the film ; this, collected in bottles, was now
properly cared for secundem artem , and great disappointment
followed ; the velvet film remained olive brown, and the water
remained colourless, save that now and then a vermilion
deposit appeared capriciously, now here, now there, at the
bottom of the containing dish. This vermilion behaved very
oddly ; no sooner was a piece of the substance drawn to the
surface than the colour, before intense red, quite disappeared,
and more strangely when the vessel was shaken to diffuse the
dye ; the colour all vanished, and instead of the water becom-
ing red, the red became water.

Of course the next step was to compare the circumstances
of the first and second collections in order to ascertain why
the former yielded spontaneously such a rich crop of results,
whilst the latter remained barren, notwithstanding my care-
ful husbandry.

The circumstances differed in unimportant particulars ;
the first specimen contained the ova already described, and
was wrapped in paper impregnated by organic (animal) mat-
ter ; the second was kept from contact with all foreign sub-
stances— but not a single ovum, with its slimy envelope, could
be found. Hoping to learn the law of the transformation of
the w^ater into blood, I imitated, as nearly as I could, the
circumstances of the first collection ; but neither india -rubber,
ammonia, nor tobacco, was efficient to provoke the colour. I
then tried glazed paper resembling that first used, but not, like
it, greasy or strained. This produced a pale tinge of colour ;
but, pale as it was, it was sufficient to indicate that there was
a something in the mass which was capable of calling forth
colour when it met with a suitable vehicle.

I was proceeding to carry out experiments founded on this
idea, when I saw an article in the ‘ Edinburgh Review’ for
April discussing M. Pasteur’s book ‘ On Spontaneous Genera-

Sheppard, on Colour in Organised Substances. 69

tion.’ In the review I found that M. Pasteur stated that
certain monads and vibrious (our liquid contains them) had
the property of changing the colours of nitrogenous and some
other substances brought into contact with them under favor-
able conditions.

Now, given the monads, what evidence have we already
to confirm M. Pasteur’s opinion ; greasy paper with some
kind of size ; sized paper, but without grease ; and the slimy
envelope of the eggs which your own nitric acid on a single
drop proved to be albuminous, all developed colour when
either of the above-mentioned substances was brought into
contact with the confer void mass. I should mention that on
one occasion a filament of Batrachospermum seemed to supply
the albuminous vehicle and the colour.

On the 3rd of May, having found, as above described, that
soluble albumen, or some similar organic substance, was
necessary to the production of the colour, I placed some of
the film of my second gathering in contact with white of egg
diluted with a little water ; the ingredients, after remaining
together for a night, developed a glassful of, as one might
have believed, magenta dye, and the dye thus obtained has
the peculiarities of the already exhibited solution ; it possesses
the same epipolar property, throwing back from its surface
all the red and yellow rays, and transmitting the blue and
violet.

The globular bottle, viewed by reflected light, looks like a
ball of red carnelian, and the contained liquid seems totally
opaque ; but, by transmitted light, it is transparent and
brightly tinted of a blue and violet colour.

I need only further remark that Ehrenberg Eidmann (who
is quoted in the e Edinburgh ’) and Pasteur seem to have
overlooked the most striking quality of the new organic dye-
stuff, viz., its poly chromatism.

Decaying algse, which have been mentioned as capable of
staining water, cannot be considered the cause of the develop-
ment of our colour, inasmuch as I find that the fresh-gathered
ferment (as I may call it) is more active than the stale, and
farther decay of the organic materials involves decay of the
colour, so that, as soon as decomposition begins (five to seven
days), this grows paler, and when it is complete the colouring
agent is powerless, decay having produced only a dirty foetid
liquid, white with floating flakes.

Note . — The vile smell which belongs to the film is not the
result of decomposition, it is most pungent at the moment of
gathering, and even on the hill-side it is almost unbearable.

70 Sheppard, on Colour in Organised Substances.

I am by no means sure that it is harmless — it certainly pro-
duces headache and sickness ; to such an extent is this the
case that experiments with the substance cannot be carried on
in the house. I may ask, and not without reason, has the
change the organisms produce in organic fluids, in their con-
sistency as well as their colour, any relation to the alteration
of the physical qualities of the blood in typhus ? Here is a
ferment which in a few hours is capable of producing a total
disorganisation of the fluid to which it is added, and the film
is composed of materials which abound in the foul undrained
localities whence fever is never absent, and in the impure
water of town wells. I hope before long to be able to give
you more information ad hoc.

The solution of coloured albumen obeys all the chemical
laws to which albumen itself is obedient, but it becomes much
less tenaceous — ropy after it has acquired the colour.

Reaction of the film upon various organic substances.

Darkness assists the changes, and is almost necessary for
the production of them.

Soluble albumen. — Albumen at the bottom of a glass, film
dropped on it, and water above, action commences instantly,
and colour of any intensity can be obtained.

Coagulated albumen. — No action; partially coagulated;
action in inverse proportion to the completeness of the coagu-
lation.

Starch. — Action slow, but continuous ; colour has a pre-
ponderance of blue.

Gluten. — Action rapid at first, then production of colour
soon ceases, but fermentation with copious evolution of gas
continues.

Gelatine. — Patent gelatine swollen and softened by cold
water — no action in twenty-four hours.

Cooked beef fat. — Action tardy, but a good colour ; appears
at last showing the different tints in different aspects very
well.

Coloured fluid poured upon soluble albumen. — The coloured
liquid has not yet propagated the fermentation (for want of a
better name) when added to fresh albumen where care has
been taken to exclude all pieces of the film. The film
coagulates albumen in a* partial manner ; when dropped into
diluted white of egg it produces threads of very opaque, very

* Not meaning incompletely, but as if selecting some parts for coagula-
tion and avoiding them.

Browning, on the Spectra of the Dichroic Fluid. 71

firm coagulum, these threads leading down from the surface
where contact first begins to the film lying at the bottom of
the glass. When the film is dipped into undiluted albumen
it appears to become coated with an imperfect coagulum, and
when this has happened I have in no instance seen any chro-
matic change take place.

Notes on the Spectra of the Dichroic Fluid described in
the above paper. By John Browning, F.R.A.S.

The spectrum of the fiuid seen by transmitted light, which
shows it as a blueish purple, is somewhat remarkable as being
the only blue fluid, Mr. Sorby has found to give particular
bands. The chief characteristics of this spectrum, represented
in diagram 1, may be briefly described thus: — Commencing
at the least refrangible or red end of the spectrum, we find it
cuts pretty sharply a short piece of the extreme red. Then
we have a strong absorption band also in the red, correspond-
ing to 2-i- of the twelve lines given by Sorby ’s standard inter-

ference spectrum.* Ten lines of this interference spectrum
I have drawn underneath spectrum 1.

A second absorption band in the green commences at line
4, and tones off gradually into the spectrum just beyond
line 5.

After the preceding paper had been read it occurred to me
that it would be a matter of much interest if a spectrum of
the fluid viewed by transmitted light could be produced.

* Mr. Sorby’s scale, jnst referred to, is an interference spectrum, pro-
duced by a plate of quartz ‘(MS inch thick, cut parallel to the principal axis
of the crystal, and placed between two Nicol’s prisms. In this spectrum
the whole visible space is divided into twelve divisions. These are counted
from the red and towards the blue. The sodium line, as shown in the dia-
gram, corresponds to three and a half. Mr. Sorby has very kindly presented
me with an exact duplicate of his own standard spectrum, from which I am
enabled to prepare others, which will give exactly similar reuflts.

72

New Microscope Lamps.

This proved a matter of some difficulty, but I effected it at
last by filling a glass vessel three inches across, and the same
depth, with the fluid, and then condensing the light on the
surface of the fluid by means of a large condensing lens. The
micro- spectroscope was placed at an angle of 90° to the con-
denser. If placed opposite to it, only a continuous spectrum
of the lamp flame is perceived, the absorption spectrum,
whic h is much fainter than the spectrum viewed by trans-
mitted light, being masked by its intensity.

The liquid viewed by this strong reflector is of a fine
carnelian red. In figure 2, I have represented the spectrum.
It will be seen that it differs considerably from the first
spectrum, 1 . A much larger portion of the red end of the
spectrum is absorbed, but not so sharply as in spectrum 1.
The strong band in the red is shifted towards the more
refrangible end of the spectrum, cutting out the edge of the
red, some of the orange, and most of the yellow. The second
absorption band is wanting, but the greater part of the light
of the spectrum is absorbed from a point between the 4th and
5th lines, and all the light is absorbed at the 7th. The part of
the spectrum which should be yellow has a strong tinge of
olive green. Of course the diagram represents very imper-
fectly the beautiful and curious appearances which the spectra
present in colour. The Rev. J. B. Reade was with me when
I made the experiments I have described, and kindly verified
the results I obtained.

On Two New Lamps for the Microscope.

By Ellis G. Lobb, F.R.M.S.

(Read May 8th, 1867.)

The lamp which I now bring before your notice is, I
think, a great improvement upon most of its predecessors.
Three things are decidedly essential in a lamp to the working
microscopist : 1. A reservoir that shall not interfere with the
proper use of the bull’s-eye condenser. 2. A small brilliant
white flame. 3. That it shall be so portable as to be carried
about with ease. These three requisites are combined in the
lamp now before you. The reservoir for the spirit (camphine
being used), although apparently small, still holds a suffi-
cient quantity for four hours’ consumption. You will per-

73

New Microscope Lamps .

ceive it is so shaped that the bull’s eye can be placed in any
direction, and as near to the flame as may be desired. Mi-
croscopists know how requisite this is when a strong light is
required for the black ground illumination, for the polari-
scope, or for opaque objects.

Many microscopists have complained of difficulties in ob-
taining and preserving good camphine. It may he purchased
at Deanes’, the furnishing ironmongers, King William Street,
London Bridge, in half-gallon cans. If the camphine is only
required for one microscope lamp, its consumption will be
slow, and its deterioration may he prevented by purchasing
one can at a time, bottling off three pints in pint bottles well
filled, tightly corked, and kept cork downwards in a dark
place. The fourth pint may be put into quarter-pint stoppered
bottles, also kept in the dark, brought into successive use,
and replenished from a pint bottle when all are exhausted.
By this means the spirit will keep for any time, and always
yield a brilliant flame. It is well not to put more spirit in
the lamp than is required for immediate use ; and the wick
must be cut perfectly level.

Mr. Lobb then called attention to the small brilliant white
flame afforded by this lamp, and pointed out the means by
which a current of air was carried in the centre of the flame
through the circular wick. To illustrate the portability of
this lamp, he observed — “ The chimney can be put in one
pocket, the reservoir, which unscrews and receives a cap at
the top to keep the spirit from oozing, can be placed in the
waistcoat pocket, and the remaining portion of the lamp will
go into the coat pocket. The lamp, being patented, can only
be obtained of Mr. Young, in Queen Street.

I have also to bring to your notice another lamp, the in-
genious contrivance of one of our own Fellows, Mr. Piper,
the inventor of the portable horizontal slide cabinet. This
lamp is contained in a small box with a sliding lid. When
required for use, the stem of the lamp is screwed into the
box-lid, and the lamp is affixed to the stem by a clip, which
enables it to be adjusted to any height. The dimensions of
the various parts, and the neat way in which they all pack
into a small compass, make this an excellent travelling lamp,
and it has the additional merit of very moderate price, ten
shillings and sixpence.

74

Iris Diaphragm proving the circular form whether expanding
or contracting. By J. II. Brown, Esq.

Although my new form of diaphragm is at first sight
somewhat complex, it is in reality extremely simple. A
glance at the diaphragm will give a better idea of its con-
struction than any amount of written description. It essen-
tially consists of a number of triangular blades (a), each fur-
nished with two axes, one of which works in a hole in the

plate (b) . The blades expand or contract the aperture of the
diaphragm by giving a rotatory movement to either of the
brass plates, whilst the other remains stationary. The blades
being thus moved simultaneously, and their edges “next
the aperture curved, they form an opening very nearly
circular.

The first diaphragm I made of this pattern contained six-
teen blades, but I find twelve or even less are sufficient.

75

On Nutrition, from a Microscopical Point of View. By
Lionel S. Beale, M.B., F.R.S., Fellow of the Royal
College of Physicians, Physician to King’s College Hos-
pital, Professor of Physiology and of General and Morbid
Anatomy in King’s College, London, Honorary Fellow of
King’s College, Fellow of the Medical Society of Sweden,
&c., &c., &c.

(Read May 8th, 1867.)

There are many questions of great general interest and im-
portance which, perhaps, from not falling exactly within the
range of subjects prescribed for consideration in any one indi-
vidual society, are scarcely ever discussed or alluded to, but
which, nevertheless, belong to many departments of science.
Of these, nutrition seems to he one. Neither the physicist,
chemist, microscopist, comparative anatomist, botanist, nor
medical practitioner, can proceed far in his inquiries without
referring to the process of nutrition, and asking what is the
exact nature of this operation by which things are enabled to
grow and multiply. Strange as it may appear, this, like
some other elementary matters which one would think natu-
rally formed one of the first steps in the study of natural know-
ledge, is very imperfectly understood, and observers are not
by any means agreed as to what nutrition is or is not. I believe
that this arises in some measure from the circumstance that
the subject has not yet been fairly studied from a microscopical
stand-point.

As the conclusions advanced in my paper have been en-
tirely deduced from the results of microscopical observations,
many of which have been already given in detail in memoirs
published in our ‘ Transactions’ some years since* — as infer-
ences derived from microscopical observation ought to be at
least as interesting to observers as mere descriptions of ob-
servations— and as there is no Physiological Society in Lon-
don, nor, considering the great number of societies, does it *
seem desirable that there should be one, I shall venture to ask
the attention of the Fellows of our Society to an attempt to
ascertain the nature of the nutritive process, and to define
exactly what nutrition is.

The more I work the more strongly I become convinced

* Trans. Mie. Soc. and Journal, 1861 to 1865.

VOL. XV.

y

7G

Dr. Beale, on Nutrition.

that there exists a sharp and well-defined difference between
living and non-living things. And in spite of all that has
been advanced to the contrary during the past ten years, it
seems to me certain that matter which is alive is in a condi-
tion essentially different from non-living matter. I shall
endeavour to show that living matter alone is nourished, and
that no non-living thing yet discovered experiences nutrition.

W e shall see that the act of nutrition involves much more
than the mere addition of new particles of matter to a mass
which already exists, as some have held. Growth resulting
from nutrition is so very different in its essential nature from
every kind of increase resulting from deposition or aggrega-
tion, that it seems to me wrong to apply the word “ growth ”
to the process of increase in these two cases, and if the term
is to be employed at all, I think it ought to be restricted to
living things only. Here, however, at the outset, I find my-
self distinctly at issue with one whose opinions on such
questions are entitled to our respect. At the same time I
cannot help feeling that if the author had observed more for
himself, and trusted less to the arbitrary dicta and inconclusive
statements of others upon elementary questions of the highest
importance, but which have been very imperfectly worked
out, he would have been led to adopt conclusions strangely
at variance with the doctrines to which he has, I venture to
think, prematurely committed himself. After affirming that
the increase in size of the plant, like the crystal, is effected
by continuously integrating surrounding like elements with
itself, Mr. Herbert Spencer says* that the food of an animal
is “ a portion of the environing matter that contains some
compound atoms like some of the compound atoms constitu-
ting its tissues.” If such be so, the peculiar substances of
which white fibrous tissue, yellow elastic tissue, muscle,
nerve, epithelium, &c., consist, ought to be present in the
white and yolk of an egg before these have undergone conver-
sion into the chick ; but we know that not one of these things
can be detected, and, in short, that development and growth
are processes essentially and absolutely different from the
mere deposition in a solid form of particles previously held in
solution in a fluid. In growth the substances dissolved in
the fluid pabulum are completely altered in composition and
properties. Their elements are entirely re-arranged. If
the elements of the dissolved crystalline matter were torn
asunder and then reunited in a different way, so as to
produce a new substance when deposited in a solid form,
crystallisation would in this one particular accord with
* ‘ The Principles of Biology/ vol. i, p. 108.

Dr. Beale, on Nutrition .

77

growth; but there is not even this resemblance. A crystal, then,
does not grow. The fungus-like (!) accumulation of carbon
that takes place on the wick of an unsnuffed candle is not
growth. The deposition of geological strata, the genesis of
celestial bodies, are not examples of growth. I think that if
Mr. Herbert Spencer would carefully study a growing micro-
scopic fungus he would modify his views concerning the
nature of growth , and admit that there is an essential differ-
ence between growth and the above physical phenomena.
From what has been stated in many physiological works the
student would be led to conclude that the tissue or formed
matter to be nourished, selected from a mixed fluid, in con-
sequence of some sort of affinity, certain constituents adapted
for its nutrition at once, and that those substances passed
from a state of solution to the condition of tissue. But no
instance is known in which any lifeless substance takes up
another lifeless substance differing from it in composition, and
converts this last into matter like itself, as occurs for ex-
ample when a simple gelatin-yielding texture increases in
amount although it is surrounded only by an albuminous
material in which no trace of gelatin-yielding substances can
be detected.

In the hope of ascertaining the essential nature of the
nutrient process we must not’ .limit ourselves to the considera-
tion of the phenomena occurring in the fully-formed organisms
of man and vertebrate animals, in which the nutrient blood
plays so important a part ; but we must extend our observa-
tion to plants and the lower organisms, which consist of ex-
tremely minute independent masses of matter in a peculiar
state of being. Many facts lead us to conclude that nutri-
tion in its essential nature is the same in all cases ; and what-
ever meaning be assigned to the term it ought to apply
equally to the lowest simplest forms and the highest and
most complex.

A simple living organism may take up a quantity of nu-
trient matter and increase in weight. Having reached a
certain size portions may be detached, and each of these, after
absorbing nutrient matter, grow and give rise to others. In
this case the nutrient pabulum is converted into living matter,
and as a result of nutrition there is an enormous gain in
weight. But, on the other hand, living bodies may take up a
considerable quantity of nutrient matter without altering in
weight, and indeed some, in spite of being well supplied with
nourishment, may actually lose in weight. In other words,
the new matter taken up may exactly compensate for old
material which is removed, or more than compensate for

78

Dr. Beale, on Nutrition.

this : or the process of removal may proceed faster than the
process of nutrition. It is, therefore, obvious that nutrition
cannot be held to mean the mere addition of new matter to a
living body.

Suppose we now consider what actually occurs when simple
living matter, like an amoeba, or a white blood-corpuscle, or a
pus-corpuscle, is nourished. Matter either in a state of solution
or capable of being readily dissolved passes into the matter of
which the living body is composed. Some of the constituents
become part of the living body, while others are given off.
The living body then increases in size. It is nourished and
grows. In other instances, as in many of the lower vege-
table organisms, and in the cells of the higher, a coloured
material or matter having some peculiar properties is formed
while the process of nutrition is proceeding. Now, this
matter did not exist in the pabulum, nor was it to be detected
in the living matter which absorbed the pabulum, but it
results from the death of the living matter under certain con-
ditions. In this case, then, the pabulum is first changed into
living matter, and the living matter into the coloured or
other formed material. In some instances this formed
material accumulates in the elementary part itself, as in the
case of starch in vegetable cells and fat in animal cells,
and there is a gain in weight. In other cases the formed
material passes away from the germinal matter as fast as it is
produced, dissolved in fluid or in a gaseous state, and no
alteration in weight occurs, although a large quantity of
nutrient matter is taken up. Usually, of the formed material
produced, part accumulates on the surface of the germinal
matter and part escapes. Consider what occurs in the
nutrition of ordinary yeast. A layer of cellulose matter which
increases by the addition of new layers to its inner surface is
formed externally. Within this is the transparent living or
germinal matter. When such a particle is nourished the
pabulum passes through the cellulose wall into the germinal
matter, and thus the substance increases ; but at the same
time some of the germinal matter becomes converted into new
cellulose, which is added to that already existing, and alcohol,
water, and carbonic acid, which escape. The germinal matter
differs from the pabulum, and both differs in physical cha-
racters and chemical composition and properties from the
cellulose envelope. We cannot make the cellulose or the ger-
minal matter from the pabulum,nor can the pabulum be obtained ,
as it was before, from either of the above substances. How
different are all these processes from the mere addition of
matter previously held in solution, as occurs in the formation

Dr. Beale, on Nutrition.

79

of a concretion, or a crystal, which increases by the superpo-
sition of layer upon layer !

I propose now to refer briefly to the process of nutrition
as it occurs in man and the higher animals. It has been said
that the life of the body is the blood, and it has been surmised
that from' this fluid the tissues derive not only the elements
of their nutrition, but their life or the properties which we
call by that name. It is, however, more probable that the
blood contains only nutrient pabulum adapted for the nutri-
tion of the tissues, which, like all nutrient matter, is lifeless ,
not living. The actual nutrition, the conversion of the pabulum
that was in the blood into tissue, is due to actions which
occur outside the vessels containing the passive nutrient
blood. As little supported by facts as the opinion above
alluded to is the doctrine that arterial blood takes special
part in the nutrition of tissues, although a student reading
any of our text books would be led to believe that the highly
nutritive properties of arterial blood had been proved beyond
all question, and that every tissue to be nourished must have
its nutritive artery. The very active nutrition going on in
the lower animals and plants under conditions not favorable
to free oxidation, and the fact that in man and the higher
animals during the early periods of life when nutritive acti-
vity is most remarkable, the blood is not so highly oxygenated
as at a later time when the nutritive operations are compara-
tively slowly carried on, seem to show the fallacy of such a
view.

Every one knows that food nourishes the body, and that
the tissues are nourished by the blood, and it is generally
believed that a high state of nutrition depends upon a liberal
diet. At the same time, however, we know that the degree
of nutrition exhibited by the body is not dependent merely
upon the quantity or quality of the food introduced into the
stomach, absorbed and converted into blood, but ujion many
other circumstances. In one individual much of the food
may be excreted in an altered form soon after it has been in-
troduced into the system, while in another a large proportion
may be converted into tissue. This difference is determined
not by the pabulum, but by the living material which is
destined to take this up, and which is concerned in the for-
mation of tissue. Some men and some animals soon become
fat upon a diet which to others would be extremely low ;
while certain individuals cannot be made fat, although sup-
plied with abundance of the choicest food. We must also
bear in mind that every tissue does not share in the increased
nutrition, and although we often talk familiarly of the in-

80

Dr. Beale, on Nutrition,

creased or diminished nutritition of the body, we refer really
to an increase or diminution of the adipose tissue, and, hut
to a less extent, of the muscular tissue. At the same time we
know that every tissue in the body is nourished from the
earliest period of its existence ; but of all the tissues when
the organism is fully developed the adipose and muscular are
most influenced by altered diet. It may be said that the
elementary parts of these tissues exhibit greater variation in
activity than those of other textures. In some men and ani-
mals it would appear that the elementary parts of adipose
tissue take up in proportion a larger share of nutrient matter
than those of other tissues ; while, on the other hand, the
elementary parts of the glandular excretory organs are, in
other individuals, the most active. The elements which in
the first would become an integral part of the body, as fat
and other tissues, would in the last escape as carbonic acid,
water, and other substances, in the excretions. It is not
possible to say why one set of tissues should be most active
in one individual, and another set in another individual, any
more than we can explain why a particular kind of food,
which is most easily assimilated by one person or animal,
would be useless or injurious to another.

As there are in the body many different tissues to be nou-
rished, and many different substances in the blood which
may nourish them, it is necessary to consider what particular
constituents of the blood are principally concerned in the
nutrition of the different textures. The opinion seems to
have been very generally entertained that certain substances
in the blood were destined for the nutrition of particular
tissues, while other textures selected from the fluid consti-
tuents are of a different character ; for instance, it has been
supposed that the red blood-corpuscles were specially con-
cerned in the nutrition of the nervous and muscular tissues,
while the white blood-corpuscles nourished the fibrous tex-
tures— that fat selected fatty matter from the blood, muscle
fibrinous material, and so on.

In a paper which I communicated to this Society in 1864,
I endeavoured to show that the blood, like the tissues, might
be looked upon as composed of germinal or living matter, and
formed material. The white blood-corpuscles and smaller
corpuscles of similar character, which could be detected in
the blood, being composed of germinal matter ; -while the red
blood-corpuscles, the albumen, and some other constituents,
were to be regarded as formed material, being composed of
non-living matter, possessing peculiar characters, properties,
and chemical composition, but resulting from changes taking

Dr. Beale, on Nutrition ,

81

place in pre-existing germinal matter. The white blood-
corpuscles, therefore, are themselves composed of living mat-
ter, which is nourished, and they cannot as white blood-
corpuscles contribute to the nutrition of any tissues whatever.
With regard to the red blood-corpuscles, it seems to me pro-
bable that they play a highly important part in equalising
the temperature in all parts of the body, taking away heat
from parts whose temperature is above the normal standard,
and contributing heat to textures which are colder than they
should be. At the same time it must be borne in mind that
the red blood-corpuscles themselves are gradually undergoing
disintegration ; and although it seems most probable that the
constituents resulting from their decay are eliminated from
the body in the form of urinary, biliary, and other excremen-
titious matters, it is not unlikely that some of the products
may take part in nutrition.

Upon the whole, however, it seems probable that the con-
stituents which form the pabulum of the tissues are those
which are contained in the serum of the blood ; and it is im-
possible to conceive how minute quantities of pabulum prone
to undergo rapid change could be more perfectly and equally
distributed to the textures, without its composition being
materially changed, than in the thin layers which each red
blood-corpuscle carries upon its surface, and smears, as it
were, upon the walls of the capillary vessel distributed to the
tissue. The arrangement is such as to reduce to a minimum
the chances of alteration in the composition of the nutrient
fluid as it traverses the vessels in different parts of the body.

From a careful consideration of the facts, I cannot help
drawing the inference that the serum is the pabulum ; that
the red-blood corpuscles are concerned in its distribution,
and in preventing changes in the composition of the great
mass of the blood, as certain constituents are removed from
it or poured into it ; and that the white blood-corpuscles are
masses of germinal matter concerned in the formation of the
serum, as well as of the red blood-corpuscles. In support of
this view, I would venture to call attention to the following
points :

1st. That fibrous tissue, bone, cartilage, muscular and
nervous textures — the two last as perfect and, as far as we
can make out, far more delicate, elaborate, and beautiful than
any of the tissues of vertebrate animals — are formed, and with
wonderful rapidity, in many of the lower creatures quite des-
titute of a nutrient fluid containing bodies corresponding to
the red blood-corpuscles of the vertebrate blood ; and that in
all these cases the nutrient fluid is clear, transparent, colour-

82

Dr. Beale, on Nutrition.

less, and contains a substance closely allied to the albumen
of serum, if not identical with it. Different plants and ani-
mals produce from the very same fluid, and apparently under
similar conditions, very different substances ; and the different
kinds of germinal matter in the body of one of the higher
animals produce formed matters differing widely in structure,
chemical composition, and properties.

2nd. That in man and the higher animals the development
of the tissues corresponds to the period of life when the blood
is not remarkable for the number or perfection of its red
blood-corpuscles.

3rd. That certain morbid growths appear and increase
rapidly in cases in which the blood has for some time con-
tained a small proportion of red blood-corpuscles.

It seems, therefore, probable that the substances taking
part in the nutrition of all the different textures of the body
are furnished by the albuminous matter of the serum, and
that the production of muscle, nerve, fibrous tissue, &c., de-
pends not so much upon the characters of the pabulum as
upon the converting powers of the germinal or living matter
which appropriates this. The substances formed by germinal
matter depend upon its vital powers and the conditions under
which these cease to be manifested, rather than upon the
presence of particular substances in the pabulum itself. Dif-
ferent kinds of germinal matter have power to rearrange the
elements of the pabulum suj^plied to them in different ways,
so that one kind of germinal matter produces muscle, another
nerve, another fibrous tissue, and so on ; each of these tis-
sues, and, of course, the pabulum itself, containing oxygen,
hydrogen, nitrogen, carbon, and some other elements, — but
combined in a different manner.

Although the opinion is still entertained by many ana-
tomists that tissue — as, for example, the intercellular sub-
stance of cartilage — is deposited directly from the blood, no
one has explained by what means the composition of the
pabulum becomes so altered as it passes through the walls of
the vessels to be distributed between the masses of germinal
matter. On the other hand, the facts advanced by me several
years ago in favour of the view that every kind of formed
material passes through the state or stage of germinal matter
have not been overthrown. The existence of germinal matter
before the production of formed material ; the continuity of
the germinal matter with the formed material in tissues in
process of development; the circumstance of no case being
known in which formed material is produced without germinal
matter ; and the demonstration that fluids will pass through a

Dr. Beale, on Nutrition.

83

comparatively thick layer of formed material, and reach the
germinal matter in the course of a few seconds, forced upon
me the conviction that pabulum invariably passes to the ger-
minal matter, and it, or at least some of its constituents,
undergo conversion into this living substance, and acquire
its properties and powers, — portions of the germinal matter
from time to time losing their properties, and undergoing
conversion into formed material. So that pabulum invariably
becomes germinal matter, and the germinal matter, not the
pabulum, is converted into formed material. I have been
accustomed to state these facts in the following simple man-
ner : — Calling the germinal matter which was derived from
pre-existing germinal matter a, the pabulum b, and the
formed material resulting from changes in the germinal mat-
ter c, I say b becomes a , and a becomes converted into c,
but b can never be converted into c except by the agency,
and, in fact, by passing through the condition, of a.

So far, then, it would seem that in the process of nutrition
pabulum passes into living germinal matter, and is converted
into this substance. The formed material or tissue which, in
many cases, constitutes the chief increase in weight and bulk,
has all passed through the state of germinal matter. The for-
mation of this germinal matter from the pabulum is therefore
the important part of the process.

It is most interesting to inquire by what means the soluble
pabulum is caused to pass into the germinal matter. It is,
I think, impossible, in the present state of our knowledge, to
explain the facts by physics or chemistry. And no form of
attraction or affinity that we are acquainted with accounts for
the passage of pabulum towards and into the germinal matter.
The question is one upon which I have ventured to specu-
late. The tendency which every mass of germinal matter
exhibits to divide into smaller portions, each part appearing
to move away from other portions, suggests the idea of there
being some centrifugal force in operation. This moving away
of particles from a centre will necessarily create a tendency
of particles around to move towards the centre ; I think,
therefore, that the nutrient pabulum is, as it were, drawn in
by centripetal currents, excited by the centrifugal movements
of the particles of the living germinal matter. How it is that
vitality gives to matter the power of moving away from
centres I cannot even attempt to speculate upon. That
this is so, general facts, open to the observation of all, as well
as the wonderful phenomena seen with the aid of the highest
powers of our microscopes, abundantly testify.

The point in which every nutritive operation differs essen-

84

Dr. Beale, on Nutrition.

tially from every other known change is this : the composi-
tion and properties of the nutrient matter are completely
altered, its elements are entirely rearranged, so that com-
pounds which may be detected in the nutrient matter are no
longer present when this has been taken up by the matter to
be nourished. The only matter capable of effecting such
changes as these is living matter, and it is very remarkable
that when this matter ceases to live, we do not detect
amongst the compounds formed at its death substances pre-
viously present in the pabulum, but new bodies altogether,
and these often vary according to the circumstances under
which the matter dies.

Desirous as I am to yield all that can be yielded to those
who maintain that there are no vital powers distinct from
ordinary force, I might say that a particle of soft transj^arent
matter, called by some living, which came from a pre-exist-
ing particle, effected, silently and in a moment, without appa-
ratus, with little loss of material, at a temperature of 60° or
lower, changes in matter, some of which can be imitated in
the laboratory in the course of days or weeks by the aid of a
highly skilled chemist, furnished with complex apparatus and
the means of producing a very high temperature and intense
chemical action, with an enormous waste of material. It is,
therefore, quite obvious that an independent, scientific man
must, for the present, hold that the operations by which
changes are effected in substances by living matter, are in
their nature essentially different from those which man is
obliged to employ to bring about changes of a similar kind
out of the body ; and until we are taught what the agent or
operator in the living matter really is, it is better to call it
vital power than to deny its existence altogether.

It seems to me childish, rather than philosophical, on the
part of any one to reassert in these days that nutrition is merely
a chemical operation, unless he can imitate by chemical means
the essential phenomena which take place when any living
thing is nourished. The passage of a fluid through a tissue
by which its structure is preserved is not nutrition, or the in-
troduction of preservative fluids into dead tissues w^ould be a
nutritive operation. A fluid may hold in solution certain
substances which are separated from it as it traverses the
tissue, thus adding to its weight and altering its properties,
as occurs when calcareous and other slightly soluble sub-
stances are deposited in the soft matrix of bone, teeth, shell,
and other textures. This is a process which can be made to
take place in lifeless matter, and has been adduced in support
of the doctrine that the tissues of plants and animals are

Dr. Beale, on the Ovarian Ova of the Stickleback. 85

formed by physical and chemical agencies only ; but it is not
nutrition. Those who advance such arguments confuse the
process of deposition of insoluble salts in a material pre-
viously formed, with the actual formation of the material
itself out of substances of a totally different composition.

Nutrition then, I think, involves the conversion of lifeless
pabulum into living germinal matter, and comprises these
distinct phenomena :

1. The contact of the soluble pabulum with the germinal
matter.

2. The separation of the elements of the nutrient substance
from their state of combination.

3. The rearrangement of the elements, and the conversion
of some of these into new germinal matter.

Nutrition is impossible unless living germinal matter be
present, and in every case in which it is known to occur new
germinal matter is produced. Nutrition is a vital process,
its occurrence is positive evidence of vitality, and nothing
like it has ever yet been effected by human ingenuity.

On the Germinal Matter of the Ovarian Ova of the
Stickleback. By Dr. Lionel S. Beale, F.R.S., Fellow
of the Royal College of Physicians, Physician to King’s
College Hospital, &c.

Plate VII.

In a paper “ On the Structure and Growth of the Ovarian
Ova of the Stickleback,” read before the British Association,
and published in the January number of the ‘ Microscopical
Journal,’ Dr. Ransom states that “ the plan of staining tis-
sues by carmine, as suggested by Dr. Beale, is not to be re-
commended ; for the ammonia rapidly dissolves the germinal
vesicle and its contents.” This remark made me feel very anxi-
ous to study ova prepared by the process of investigation
condemned by my friend ; and I take the earliest opportunity
of communicating the results to the Society. It is a source
of regret to me that I had not prepared some ova for Dr.
Ransom’s examination before he expressed himself so de-
cidedly against the mode of investigation from which I have
derived great advantages. I feel sure from his remarks that
the process has not been properly carried out by him.

I shall not occupy time by recounting in detail the new

86 Dr. Beale, on the Ovarian Ova of the Stickleback.

facts in connection with the structure of the germinal vesicle
and the development of the ovarian ova learnt by the process
of investigation I have pursued, but content myself with re-
ferring to the drawings in Plate VII, and the descriptions
underneath them.

In conclusion, I will only observe that the ammonia does
not dissolve either the germinal vesicle or its contents ; and
I fear that when my friend sees the drawings he will be in-
clined to reply that, so far from exhibiting solvent properties,
the fluid has precipitated particles from the contents of the
germinal vesicle, and has actually formed things which do
not exist in the natural state. I will not, however, now
discuss this matter.

The best results are obtained by diluting the carmine fluid I
have recommended with a little water and spirit of wine. I
have already stated that, for special inquiries, the staining
fluids will be improved by slight modifications, which will sug-
gest themselves to any observer after a few careful experi-
ments. So, also, some things are stained most easily at ordinary
temperatures, others -at a temperature of 100°; but it would
be tedious beyond measure to give detailed directions for
each individual object. If the experimenter considers the
principles upon which the success of the process depends, 1
think he will find little difficulty in carrying it out. Like
many other operations, practice is required before the best
results are obtained, and most who anticipate complete suc-
cess upon the first trial will, I fear, be disappointed in this
as in most other scientific investigations.

T RAN S ACTION S OF THE ROYAL MICROSCOPICAL

SOCIETY.

Some Remarks on the Parasites found in the Nerves,
&c., of the Common Haddock, Morrhua oeqlefinus. By
R. L. Maddox, M.D.

(Communicated by G. Busk, Esq., F.R.S., F.R.M.S., &c.)

(Read June 12th, 1867.)

Although the “ spheroidal bodies,” the subject of the
present communication, were discovered and partially de-
scribed by Monro secundus, much more fully investigated by
Professor Sharpey in 1836, who was in the habit of men-
tioning them in his lectures at the University College, and
subsequently by Mr. H. Goodsir, whose paper “ On the
Anatomy and Development of the Cystic Entozoa,” read
before the York meeting of the British Association, 1844,
was published in ‘ Goodsir’s Anatomical and Pathological
Observations, 1845 f still, from the interest that attaches to
all knowledge of Parasitic life, whether vegetable or animal,
from the scarcity of the last-named work, as well as from the
difficulty attending the correct investigation of the structure
and relationship of these peculiar creatures, I am induced to
offer the accompanying notice as a further elucidation of their
organization, with some general remarks. To my friend
Professor Aitken, of the Victoria Hospital, Netley, I am
indebted for calling my attention more particularly to these
bodies, as a subject worth more extended examination.

Dr. Monro, secundus, found peculiar “ spheroidal bodies”
existing on the surfaces of the brain and nerves of the Gadidae,
which are known to be encysted entozoa containing a living
parasite, similar to Distoma. I have noticed them chiefly "on
the nerves, and more particularly on the caudal nerves,
extending in some fish of about fourteen inches long, to two
and a half inches upwards from the tail. On making an
incision along the caudal extremity over the spinal column of
the common haddock, and carefully dissecting back the
muscles, the series of nerves as they pass out from the spinal
vol. xv. h

88 Maddox, on Parasites of the Common Haddock.

cord are found studded with flattened bead-shaped bodies
plainly visible to the unaided eye. Removing a portion of
one of these nodulated nerves, placing it in water under the
microscope if the fish have not been too long dead, these
“ spheroidal bodies” of Monro are seen to be cysts, generally
imbedded in and displacing the nerve structure, and con-
taining a spinous parasite bent up, which in many cases can
be seen to execute partial movements of revolution on an axis
at right angles to its length. After removing the surrounding
nerve fibres and exposing the cyst to more complete view, it
is seen to contain besides the animal, a grumous fluid and
numerous oily-looking globules, set in motion by the move-
ments of the parasite.

The cyst seems to be composed of a more or less compact
substance, brownish in colour, especially by transmitted light,
and lined by a softer but somewhat brittle substance, inter-
nally having, as seen through the walls of the cyst, fissures in
every direction. The cysts are of a very variable size ; some
of the smaller not more than the -j-Aoth of an inch, others
much larger, but the average may be taken as T-g-oths of an
inch, more or less ovoid and flattened; some are, as in PI. VIII,
fig. 6, double ; that is to say, when two cysts by the growth of
the creature and expansion of the walls have met, the ad-
joining walls are removed, and the two cysts form but -one
cavity, and, as in the sketch, contain two parasites. This
appearance is not very common. I have met with it twice.
On careful examination of the cysts, both in situ and removed,
I could find no aperture, nor under compression did the
cysts rupture more easily in one direction than in another.
These cysts are described by Mr. Goodsir as similar to the
cysts of Cysticercus , as also to the cysts of Trichina spiralis
Gymnorrhyncus horridus and a small Filaria inhabiting the
livers of some fish. “ The cysts of all these worms have
similar structures- to those of Cysticercus, namely, an external
membrane composed of compressed cellular tissue, and an
internal membrane containing absorbing cells, through which
the contained animal obtains nourishment.” Mr. Goodsir
cites the encysted Gymnorrhyncus found in the liver of the
sunfish as an example, — the “ inner membrane of the cyst
containing absorbent cells is covered anteriorly with a very
thin layer only of the external membrane, so that it is enabled
to absorb the nourishment from the external textures in great
abundance, which thus enables the animal to move forward
as well as obtain a supply of food.” Mr. Goodsir states that
“ Professor Owen, in the description of a microscopic entozoon
infesting the muscles of the human body, considered the cysts

Maddox, on Parasites of the Common Haddock. 89

to be only 4 condensed textures of the infested being.’ ” Dr.
Knox, 44 that it belongs especially to the parasite.” Mr.
Goodsir’s brother, as regards the parasite in the liver of the
sunfish, says, 44 May we not suppose them to be part of the
original ovum, within which the animal was formed, and
within which it passes its term of existence.” The special
cyst of the Distoma in the nerves of the haddock, is described
in the article from which the above remarks are quoted, as
consisting of 44 three tunics : an external, which appears to be
derived from the areolar texture of the infested animal, a
middle and internal belonging to the parasite ;” 44 the second
tunic is a fine transparent membrane which lines the first,
and has in its turn its internal surface covered by an epi-
thelial layer, which is the third tunic of the cyst. The
epithelia are flat, irregular in shape, and somewhat opaque.
The third or internal layer, formed by them, breaks up under
the glass plates, so as to present rents or fissures passing in
various directions over it.”

I have not been able to satisfy myself of the correctness of
these particulars, but rather regard the cysts as the results of
a secretion from the surface of the parasite, in fact as Von
Siebold describes for the Cercariae. 44 After a Cercaria has
been for some time in the water, first creeping and then
swimming about with manifest restlessness, it gathers itself
up into a ball and emits from its whole surface a mucous
secretion, which soon hardens, and since inside of this mucous
mass the worm, coiled up into a little ball, turns round
without stopping, invests it as it were in an eggshell.”*
The secretion in the present case I believe to arise chiefly
from the lower part of the body, for I have found in several
specimens removed from the cysts a grumous granular matter
exuded and adherent to this portion, and forming a layer at
the surface of the body of some thickness ; also on wiping
over the surface of the animal in water with a fine camel-hair
pencil under the erecting microscope, a considerable amount
of finely granular substance can sometimes be remarked.
Moreover, I cannot detect any distinct tunics in the cyst, nor
any epithelial structure as such, with nuclei coloured by
carmine, or by maceration, liquor potassae, &c. &c.

The outer portion seems to be of a condensed mucous or
almost chitinous material, of a variable thickness and lined
by a more or less transparent friable substance which, on the
growth of the parasite in its expansion, splits up into
irregular plates of some substance, having fissures that reach
to the inner surface of the external or more condensed part.
* Von Siebold on Worms, 1856-7. Pub. by The Sydenham Society, p. 20.

90 Maddox, on Parasites oj the Common Haddock.

I should regard the cyst as passive, not endowed with growth
or conversion of material , but sufficiently porous to admit
pabulum through its surfaces ; and it seems probable the
creature is also capable of reabsorbing this deposited matter,
as in the case of the removal of the walls of closely adjoining
cysts, figure 6, which, we could hardly expect without some
trace, if the cysts contained an external tunic of the fibrous
and elastic tissues of the infested animal. Although the
larger number of these cysts is placed in the very structure
of the nerve, the component fibres and vessels, &c., seem to
be uninjured, the expansion and growth of the parasite
appear to have been most gradual. I could find no change
pathologically, nor can we say if there had been any effect
in the physiological relations of the surrounding parts. I
saw no wasting of the structures, and the only difference
noticed was in some of the neighbouring muscles ; they
appeared here and there to be somewhat discoloured, yellower
than the rest, a fine granular substance investing the fibres
and fasciculi, though the intimate structure was quite as
perfect as in the normal tissue. I cannot say whether any
portion of the interior of the cyst should be regarded as the
remains of ecdysis. In some, loose particles are found, which
may be excreta.

On rupturing the largest of the cysts, containing the
entozoon alive, with the dissecting needles, a small quantity
of viscid fluid with variable sized oily-looking globules
escapes, and with it the parasite ; almost immediately if this
be done in water or any saline liquid, or weak glycerine, I
have noticed the creatures retain much of the form in which
they emerged, andremain more or less permanently contracted:
but in warm saliva, for the intimation of wdiich I am indebted
to my friend Professor Aitken, the animal often moves some-
what freely about with a slow graceful motion, and the
internal textures are very much less obscured than in other
media, which do not render them too transparent for distinc-
tion. I have watched one specimen alive in this medium for
seven hours, how much longer it remained living I can’t say, as
I left it to retire for the night, but the next morning at eight
o’clock there were no signs of life. The general aspect of the
creature is elongated, roundish, rather narrower posteriorly
and somewhat leech-like, about 7^0^ to iVe-th of an inch in
length, the entire surface of the body covered with minute
spines set backwards, but more particularly, as pointed out by
Mr. Goodsir, evident on the entire dorsal aspect. It is pro-
vided with an anterior or oval disc, and a central one situated
about the junction of the first and second third of the body.

Maddox, on Parasites of the Common Haddock. 91

In the interior is noticed a large, dark-looking sac, occupying
a great portion of the inside of the creature, extending along
the two lower thirds in a sigmoid or partially curved direc-
tion, and terminating at a distinct posterior outlet ; looking
almost black by transmitted light, and by reflected light of
a dead white ; the contents of this sac are made up of minute
globules of a highly refractive character, and I believe of an
also albuminous matter enclosing air. Within the sac, in the
living creature, these minute globules may he seen in irre-
gular motion, and occasionally a portion is emitted at the
outlet. Whether this is to be regarded by some as a respira-
tory sac or urinary apparatus, or whether it belongs to the
digestive system I am not certain, or whether it is not con-
vertible at some future stage of the creatures existence into
some important and defined organ, is doubtful. It exists
more or less in all, though in the most minute examined it is
exceedingly trivial. The large circular disc at the anterior
extremity of the creature has numerous fibres or folds,
circular and radiating, with an aperture that varies from
a circle to a sharp elipsoid, which, from analogy in the
other distoma, we may regard as a mouth, — though, from the
density of the superposed structures, I have never fairly seen
an oesophageal tube, — I have noticed only, as in the fig. 4,
indications of such being present. Below the anterior disc
on either side of the body, are small irregularly placed
cellular bodies ; I have counted sixteen on one side, but
could not make out the same number distinctly on the other
side, made up of nucleated cells, or if we regard the cell as a
single structure, with about eight or more nuclei. These were
not noticed in any specimen before staining some of the
creatures by Dr. Beale’s plan, when they were quickly re-
cognised and are figured in fig. 4, those the lowest in the
body are the most distinct, the largest and most nucleated in
their structure. Are^they unimpregnated ova, or yelk glands ?
These bodies are best seen on the dorsal aspect, though in
no single case have I found them symmetrical, the parasite
dying in some contrary position, though placed as such in
the figure, which is made up in one or two of its internal
organs from an extended series of observations on various
examples. (My best specimen I lost from slightly warming
the mounted slide, the glycerine appearing to act on the
delicate sarcode structure of these bodies as a solvent. This
is named as a caution to others.) Situated more centrally
are two tubes which appear to be united below the anterior
disc by a cross branch, of which, however, I am not absolutely
certain, the parts being much obscured ; as they extend

92 Maddox, on Parasites of the Common Haddock.

downwards, they are distinctly nucleated (like the biliary
tubes of some insects), as figured, and at the lower parts
join and apparently end by one tube posteriorly, but whether
in a blind extremity or in conjunction with the large
sac, I will not assert, though disposed to believe the latter.
Are these tubes a portion of the digestive canal, or hereafter
to become ovaries ? At the centre of the upper part of the
middle third is a second disc, which on tracing inwards
appears to have an aperture with a short tortuous canal, or an
oblique passage, that terminates in a strong pouch, regarded
as the uterus, which generally contains several large globules
and some very minute ; its walls are rugose, thick, cellular
when seen on end, and have both circular (which are very
marked) and elongated fibres in its walls. On a side view it
often appears divided by these into little square areas. I
could not find any satisfactory connection of the sacculated
end of this organ with any other, nor indeed of its mouth or
neck. The walls of the disc have circular and radiating folds
or fibres, the radiating in some cases very distinct, vide

%• 4-

Mr. Goodsir described and figured a small anterior pore in
front of the acetabulum. May this pore not be the mouth of
an erected short tube, which, when drawn back into the neck
of the sac would give the appearance corresponding to Mr.
Goodsir’s description, but in other dispositions of the parts,
to a small orifice beneath the disc. I could not satisfy myself
on these points, though am inclined to view it as now stated
(fig.8).

Slightly below this organ and to one side are seen, in large
specimens, five other bodies, two small, two large, and one
intermediate, but more resembling the former ; they appear
to me as connected. The intermediate one is circular, some-
what different in aspect from the others, and contains highly
refracting bodies ; the next smaller in size is a cell with a
segmented arrangement of about five nucleated structures.
I could not trace in any specimens the exact attachment of
this organ to the lowest of the sixteen nucleated cells before
described, but think such exists ; below this, the next small
circular body is more solid, the divisions are broken up into
a greater number, and evidently some change appears to have
been effected in it ; — beneath this are two much larger and
more compact oval or roundish bodies, very distinct, the
upper one generally the larger of the two : they are con-
nected together by bands, whether ducts or not I could not
determine. Speaking of these bodies, Mr. Goodsir writes,
“ The two larger globular masses are very constant, and as

Maddox, on Parasites of the Commori Haddock. 93

well as the two smaller contain a mass of particles apparently
nucleated. From the two larger 1 have only been able to see
faint traces of what appeared to be ducts, passing in the
direction of the smaller masses and towards the neck of the
pyriform sac. Whether these convoluted bodies be ovaries or
convoluted oviducts, and the pyriform sac a uterus, or
whether the former be testes and the latter the female organ,
as in the arrangement discovered in the other distomas, or
whether they be reproductive organs at all, I have failed in
satisfying myself, in consequence of the delicacy of their
texture and the comparatively dense integument of this part
of the animal.” Thus it appears he did not notice the double
row of small globular bodies. We have now the large oblong
albuminous (?) sac crossing the body and terminating below,
whilst at the lower third, situated rather to one side, is
a curious and constant organ much denser in the larger than
in the smaller animals. It is an elongated body slightly
curved on itself at its upper part, containing a central canal,
in which in living specimens can be seen minute particles in
motion ; the sides of the upper half consist of highly refrac-
tive parts, apparently set at an angle to the canal, the upper
end being united by a cord or duct to the two large circular
bodies ; the lower part of the organ is surrounded by circular
fibres, a few longitudinal also being visible. At this part is
a peculiar twisted arrangement, of which I could not deter-
mine the real nature ; traced further downwards the widened
contorted portion appears to terminate in a funnel-shaped
cavity, this having a distinct exit to the side and near
the outlet of the large dark sac, — vide fig. 4. In some
positions I noticed a small projecting hody near its centre,
which I am led to suppose connects this at about its middle,
with either the tubes of the globular bodies, or of the terminal
duct of the convoluted nucleated tubes. Is this both a male
organ and oviduct combined, — the minute particles seminal
matter, the upper part of it the testis, the medium size cir-
cular body a seminiferous receptacle, the two large globular
bodies ovisacs, containing fecundated ova, and the two smaller
globular bodies as receptacles of the sixteen, more or less,
yelk masses, preparatory to impregnation ? There are still
to be described four rapidly vibrating or pulsating points, at
the lower third of the body, as in the fig. 4, indicated by
the letters p. o, they are seen as narrow, bright, rapidly
quivering lines in one position. When examined with a
power of 445 diameters they appear -A-th of an inch in
length, and in another aspect as a small circular spot. The
pulsations were not equal, some being quicker at one than

94 Maddox, on Parasites of the Common Haddock.

at the other spot — p. o', pulsating much faster than the
opposite p. o'. I am not aware of these being noticed by
former observers. They were shown to others. I expect
they are valvular folds, and connected with some arrange-
ment of vessels, of which I could only find faint indications
here and there, and which may belong to the vascular system,
the trunks of which, Mr. Goodsir states, are most apparent at
the lower third of the body.

The large oval or globular masses removed from the
interior of the animal by the dissecting needles, and placed
in the compressorium showed a distinctly cellular or seg-
mented structure. The lower or male (?) organ removed, gave
under compression little more than mere outline. The twisted
condition the creatures often die in, and the apparently dis-
turbed position of the internal organs with their delicate struc-
ture, add a considerable difficulty in distinctly ascertaining the
exact relations of the various parts. It is by examining a large
number of specimens, which I have done, that we shall
possibly arrive at anything like a correct description. In
the integument, both circular and longitudinal fibres and
very numerous nuclei are evident, and throughout the whole
interior of the body, in many cases, a kind of loculated
appearance, probably from sarcode bands passing in various
directions presented itself.

In the glutinous textures covering the brain I found only
two parasites, none in the brain or spinal cord or canal, none
in the textures of the eye, one on the optic nerve ; and
between the optic lobes, forming a depression in one of
them, was a small brownish-looking spot, which, when
examined, showed groups of, and single, yellowish-looking
bodies of variable size, but no distinct structure : they ap-
peared to be scattered in the nerve substance.

According to the opinion of many the encysted entozoa are
regarded as immature parasites, or in their pupa condition,
and doubtless this may be the case ; but how far the peculiar
creature under consideration has deviated or passed to a
higher grade, and become partially sexually mature, I cannot
say, hut venture to hazard the following suggestion : — That
we have here, as in other Distoma, a hermaphrodite creature,
which, in its progress towards a reciprocal sexual maturity,
yet carries on self-impregnation, so that, at the death of its
host, and thus within a moderate time, (I have seen them
alive in fish more than forty-eight hours dead, probably three
days,) of its own death, impregnated ova may be set free to
again become, perhaps, Monostomum embryos to pass through
a Cercarial stage, or the lowest phase of a Trematode life.

Maddox, on Parasites of the Common Haddock. 95

Whether these ovoid globular bodies should be regarded as
u sporularia,” in which “ sporulse ” are developed, using these
terms, as Von Siebold, to mean germs, which are not only de-
void of the ordinary constituents of an ovum, as vitelline mem-
brane, yelk, germinal vesicle, and the so-called germinal
spot, but in which the further development of the germ-body is
not preceded by those conditions, (I mean that of “ impregna-
tion ” by means of special seminal matter produced in a
testis,) which are essential to the development of true ova de-
veloped within an ovarium, I cannot decide. In a paper
translated by Mr. Dallas, in f Annals and Magazine of
Nat. Hist.,’ No. cii, 1866, there occurs this passage from
Professor R. Leuckart, in speaking of the trematode worms :
“ There are trematoda, the embryos of which even attain sexual
maturity in their Rhabditist-/orm, and only become 'parasitic
again in their progeny — trematoda, consequently the history
of which presents us with no simple alternation of the con-
ditions of life, but with an alternate sequence of free and
parasitic generations. And, what is more wonderful, both
these generations are sexually developed ,both are produced from
ova. There, therefore, we have nothing to do with an ordi-
nary alternation of generations such as occurs, for example,
in the Distomese, but with a process hitherto almost unheard
of in the animal kingdom, and which calls for our considera-
tion the more, because we are accustomed to regard the
sexual development of an animal not merely as the sign of
its perfect maturity, but also as the criterion of specific indi-
viduality.”

The view of self-impregnation has been held by some, but
Dr. Cobbold thinks erroneously, for he says — “ Having
found two of the flukes (. Distoma conjunctum, Cobbold)
sexually combined, a fact of great significance in relation to
the probably erroneous notion entertained by some, that the
hermaphrodite flukes are capable of self-impregnation ; ”
still, as this only proves the one form of congress, to my own
mind it does not present any serious difficulty, seeing that
almost every day fresh ideas, through increased knowledge,
are adding to the peculiarities of the “ ways and means ” by
which the deviations from the ordinary paths of develop-
ment are effected, to yet carry forward the one grand end —
the continuation of the species. Indeed, to me it almost
seems less extraordinary that in the hermaphrodite, which is
itself a deviation, we should have the power of direct develop-
ment up to at least a certain form, if not to the full nature
of the highest phase of the creature’s existence ; thus might
it not be that the type for self-impregnation, allowing it to

95 Maddox, on Parasites of the Common Haddock.

exist, rather carries forward the animal under some lower form
of being (according to the admitted view, that the present
form has to pass to a higher stage before reciprocal congrega-
tion), provided it cannot, under its present circumstances,
reach the higher mode of maturity than that it should perish.
Singular, indeed, is the progressive series of stages in the
“ alternation of generations ” or of “ germination,” “ aga-
mogenesis,” when the offspring is to deviate, both by its
appearance and its progeny, from its parents, and at last,
after such transitional forms, arrive at that perfection when
the result of reciprocal sexual impact is the genuine ovum of
the specific type, — or that the young should be like to great-
grandparents at one period, and at other stages have no
relationship by similarity of external figure. Is this singu-
larity not greater than hermaphroditic self-impregnation ?
No one may have outwardly witnessed the act of self-impreg-
nation, but, if the means of passage for the male influence
exist internally, we have no more than an inward self-
impression which exists in a reciprocal external condition in
other creatures, and which can be effectually practised by
artificial methods, as in fish-hatching. The question is, do
we really know the import or exact nature of the organs we
figure as existing in the interior of many small beings ? How
various the terms employed, how questionable if strictly
correct. We have our yelk-forming glands, our testes, our
gemmarium, our ovaries, our oviducts, our excretory, urinary,
or respiratory, or, in fact, any other apparatus that suits our
views ; therefore we may err, however much we may strive in
truth, “ for wisdom will always have a microscope in her
hand ; ” still, when we look “ into the life of things,” we
cannot limit the rules or restrict the powers impressed on
certain animals by the Great Originator, or contrast His
creative powers, however much they offend or oppose our
accommodating hypotheses ; our ignorance is here the boun-
dary, and certainly must not be a substitute for our imaginary
knowledge.

It is doubtful if we are even now able to state correctly all
the generic relations of this genus, of the order Sterelmintha,
family Trematoda, found in the cod, haddock, and whiting.
I at first looked on these ovoid bodies as proceeds of diges-
tion, retained to be expelled eventually, and this through the
alteration produced in their appearance in various media in
which they were examined, the same acting in a similar
manner on the little quantity of granular material found in
the middle pyriform sac of so^e ; but by using saliva I
obtained a better mode of examining these bodies.

Maddox, on Parasites of the Common Haddock. 97

On turning to Dr. Cobbold’s valuable work on Entozoa,
at p. 36 is figured a Distoma, the “ Gasterostoma gracilescens
(Wagener), from the intestines of the angler, Lophius pise a-
torius, magnified 60 diam.,” very like the subject of the
present article, in a more advanced condition. Indeed, I
think, as we shall presently see, it is more than probable
that this is one of the higher phases of Distoma neuronaia
Monroii in its free state of Gasterostoma — Dr. Cobbold
writes, “ In this singular genus the ventral sucker seems
to have taken the position usually assigned to the oval
opening, whilst the latter is placed lower down, towards the
centre of the body. The digestive caeca also disappear,
leaving only a short stomachal cavity, which reminds one of
the same viscus in the imperfectly organised sporocysts or
redke. The yelk-forming glands exhibit conspicuous, round,
secreting cells, the testes also being largely developed. I
have also noticed two other small bodies, one of which
probably represents the ovary or germ stock, whilst the other
may be referred to the receptaculum seminis, or posterior
seminal vesicle of Yon Siebold. This connection between
these several organs is not seen in this specimen, but their
relative position is well shown. When the species first
came under my observation I naturally followed Rudolphi,
wTho described this Trematode as a Distoma (. Distoma graci-
lescens, Eudolphi). I remember seeking most diligently for
the digestive tubes, being greatly puzzled, not merely by
their absence, but also by the character and position of an
organ which we now well know to be the sheath of the intro-
mittent appendage. The uterus also terminates in its imme-
diate vicinity, opening externally by a common outlet. The
anatomy of this genus has been pretty fully illustrated by
Yon Siebold. According to Molin, the excretory, water-
vascular organ (or respiratory apparatus, as he interro-
gatively puts it) consists (in Gasterostoma fimbriatum ) of a
broad central tube, occupying the entire length of the body.
In connection with this tube he did not discern any branches,
but he represents it as a simple sac, opening externally at the
caudal extremity.”

Now, referring to Couch’s excellent work on ‘ Fishes,’
vol. ii, 1863, p. 129, art. “ Lophius piscatorius,” he says,

the angler sometimes seeks its prey at mid-water, — a fisher-
man had hooked a codfish, and while drawing it up he felt
a heavier weight had attached itself to his line ; this proved
to be an angler. How indiscriminately these fishes feed on
each other appears from the fact that, in the stomach of an
angler which measured two feet and a half in length, was

98 Maddox, on Parasites of the Common Haddock.

found a codfish that measured two feet; and in the latter
were the skeletons of two whitings, within which again were
other small fish.” As similar parasites, as previously noticed,
are found in the cod, haddock, and whiting, it is possible
that in the angler the Distoma neuronaia Monroii finds its
perfect habitat, unless again through the angler it still passes
to some larger predatory fish — I hardly think to the seal or
birds. The food of the haddock is chiefly shell-fish. Couch
recommends naturalists to search in them for interesting
species — he having found twelve separate species among a mul-
titude of univalve and bivalve shells. Perhaps here begins the
earliest stage of the parasite, so imperfectly noticed in this
article, but which I hope to have shown presents much
interesting matter for future research.

Note. — From Dr. Sharpey’s letter to Mr. Goodsir, as pub-
lished in the f Anatomical and Pathological Observations
i( When in Berlin some years ago, the late Professor Ru-
dolphi remarked to me in conversation, that he thought it
not unlikely the little bodies discovered by Dr. Monro (second)
on the nerves of the cod, haddock, and other allied fish,
would turn out on examination to be entozoa : and he su£t
gested that I should take an opportunity of inquiring into
the point, on my return to Scotland. Accordingly, in the
autumn of 1836, I examined these bodies in the haddock or
whiting, I really forget which, but I think it was the former,
and found that each of them was a little cyst, containing a
distoma, which could be easily turned out from its enclosure
aliveJ The specimens I examined were from the membranes
of the brain. This observation was made in Edinburgh, and, on
going to London soon after, I mentioned the fact to Mr.
Owen ; and I have been accustomed to take notice of it in
my lectures ever since, suggesting at the same time that it
would be well to search for these or for analogous parasites
in the nerves of other animals, as it was not likely that the
Gadus tribe of fishes should be the only example.” * * * *
“ Rudolphi, as far as I know, never examined the structure
of the spheroidal bodies of Monro ; and the only notice of
them I have met with in his writings (to which he did not
refer me) is in his f Historia Naturalis Entozoorum,5 vol. ii.
Part 2, page 227 , where, under the head of “ Dubious En-
tozoa,5’ he enumerates an object described and figured by
J. Rathke, under the name of “ Hydatula Gadorum,” which
that observer found in the pia mater of the Gadus morrhua
and G. virens, often in great numbers, and wRich appeared
to be a vesicle containing a worm. The nature of the para-

Rymer Jones, on Corethra plumicornis.

99

site was doubtful, but supposed in some degree to resemble
that of a cysticercus, and hence the name applied to it by
Rathke ; but Rudolphi denies that it is a cysticercus, though
he does not know to what genus to refer it, he adds 4 an
Cucullanus.’ (? ) 99

On the Structure and Metamorphosis of the Larva of

Corethra plumtcornis. By Professor T. Rymer
Jones, F.R.S., F.R.M.S., &c.

(Read June 12th, 1867.)

Having towards the close of last summer met with a
pond in my vicinity well stocked with the larvse of the
Corethra plumicormis, objects so tempting to the microsco-
pist, both on account of their marvellous transparency and
the facility with which they may be obtained for observation,
I was induced, preparatory to a more minute investigation
of their structure, to map out, as it were, the grosser features
of their anatomy, and thus obtain a kind of chart, the minor
details of which could be filled up as opportunities presented
themselves, and for this purpose sketched under the camera
the main outlines of their economy. As the season again
approaches when these larvae are procurable, from the study
of which so much information may be reasonably expected
relative to the economy and metamorphoses of the Culicidae.
I have thought that it might possibly facilitate the explora-
tion of other observers in this interesting field of study were
I to place the drawings thus made at the disposal of any
members of the Society who may feel an interest in the
subject.

There are indeed many points of high physiological im-
portance susceptible of solution, by a careful examination of
this insect in its different stages of growth, which in other
species would seem hopelessly beyond research, owing to
their dark hue and the general opacity of their integuments,
whereas the glass larva, as it is not unfrequently called,
seems eminently constructed for the purpose of courting our
observation, insomuch that it might almost be regarded as
purposely intended for inspection ; one of those peep-holes
left by Providence, through which a glimpse may be obtained
of the elaborate machinery of creation.

It would be a waste of time, before an audience, to every
member of which the larva in question is no doubt a familiar

100 Rymer Jones, on Corethra plumicornis.

object, to dwell upon the general form and appearance of this
elegant but ferocious creature, — the symmetry of its shape,
the vivacity of its movements, the fan-shaped plume beneath
its armed tail, which, like a fin, propels it through the water,
its pike-like voracity, or the ruthlessness with which it makes
an onslaught on its prey ; and yet the descriptions of it,
given even by modern entomologists, are lamentably meagre,
and give but a feeble idea either of its carnivorous propensi-
ties or its formidable armature. Its mouth presents a ter-
rible apparatus, composed of numerous pieces, the homologies
of which might furnish interesting subject for discussion. In
their disposition they remind us of the foot-jaws of some of
the Branchiopod Crustaceans (such as Chirocephalus) , and in
like manner are equally instruments of progression, and
weapons for the capture of prey. The anterior pair, articu-
lated to the apex of the snout, are of great strength, and are
moved by powerful muscles, distinctly seen through the
transparent covering of the head. At their extremities they
bear fan-like tufts of stiff setse, that, when expanded, form
powerful oars, the downward strokes of which, when ener-
getically made, have a marked effect in aiding the progress
of the animal through the water. More frequently, how-
ever, their movements are of a gentler character, and only
serve to cause the influx of a constant stream towards the
mouth, the effect of which extends to a considerable distance,
attracting, like a little Maelstrom, the smaller animals that
come within its vortex.

The second pair of these oral appendages presents a very
different structure. They are composed of numerous narrow
laminae, much resembling, in their arrangement, the plates
of whalebone in a whale’s mouth, and indeed they perform
a very similar office. These plates, represented in the draw-
ing (PL IX) in a collapsed condition, can be spread out like
the walls of a tent, so as to enclose as in a net whatever small
animals may be brought within their expanse by the intrant
current above alluded to.

The third pair consists of two elegantly-shaped instruments
wherewith the creature adjusts, as with a pair of hands, the
position of the imprisoned victim, so as to pass it easily along
the fatal road, and hand it to the embrace of

The fourth pair, which in function at least must be com-
pared to palpi. These pieces are of large dimensions, fur-
nished at their extremities with sentient vibrissse, that remind
us of the whiskers of a cat, and with a terminal tuft of greater
strength and thickness, whereby the prey is seized and passed
backward to the gaping jaws.

Rymer Jones, on Corethra plumicornis. 101

These last consist of two pairs of crushers, the maxillae
and the mandibles, both armed with formidable fangs, while,
to complete the deadly apparatus, spikes of different shapes
surround the immediate margin of the mouth.

The internal digestive organs are not less remarkable than
the complicated machinery described above.

The commencement of the alimentary canal presents a
spacious crop, the walls of which are very strong and mus-
cular ; to this succeeds a gizzard, armed internally with
teeth, arranged in densely-crowded phalanx — from this a
tube of remarkable slenderness and of considerable length
leads to the true ventri cuius, the walls of which are glandular
and minutely sacculated. To the pyloric extremity are
attached four (so called) hepatic vessels, while the intestine
is simple and slightly dilated towards its extremity. On
placing one of these larvae between the plates of the com-
pressor, and pressing it moderately, a very curious phenome-
non presents itself. The muscular walls of the crop, thrown
into violent action, tear away the gizzard and its slender
tubular prolongation, and becoming suddenly everted, pro-
trude from the mouth, having, in this condition, very much
the appearance of the unfolded proboscis of an Annelidan ; a
resemblance much enhanced by the denuded teeth of the
gizzard, that protrude from the extremity of the everted
crop, which latter continues for a long while to exhibit peris-
taltic movements ; while the crushed and mangled bodies of
the swallowed monoculi, upon which these larvse principally
subsist, are cast into the surrounding water, and testify to
the efficiency of the curiously-formed apparatus.

In these diaphanous larvae, the action of the heart is very
beautifully exhibited : the contractions of its various cham-
bers succeed each other consecutively, with an apparent
energy of purpose that reminds the observer rather of the
untiring pumping of a steam-engine, than of those rythmical
undulating movements which we should expect to witness in
a viscus having walls so thin and transparent, and at the
same time so isolated. It is therefore by no means surprising
that the dorsal vessel should be provided with a largely-
developed system of ganglionic nervous centres, the existence
and distribution of which are plainly traceable when using
the higher powers of the microscope. These consist of nume-
rous minute corpuscles, closely resembling in their appearance
Paccionean bodies, and are distinctly perceptible in the
vicinity of each compartment of the dorsal vessel, to which
they are connected by slender filaments. These minute
ganglia are usually disposed in groups, varying from three to

102 Rymer Jones, on Corethra plumicorms.

five in number, suspended in the cellulosity surrounding the
heart.

But perhaps the most characteristic feature in the economy
of these larvae is the existence of four remarkable organs,
situated — two of them in the thoracic region and two near
the centre of the posterior half of the body. These strange-
looking masses, conspicuous from their jet-black colour, are
placed in pairs, and uniformly occupy the same situations
corresponding with the centre of gravity, or rather of flotation
of the two halves of the animal to which they respectively
belong. In form they are more or less kidney-shaped/ and
are to all appearance completely isolated and unattached to
the surrounding structures. On crushing these kidney-shaped
bodies beneath the compressorium, they are found to be filled
with air, by the compression or rarefaction of which the
creature is enabled to rise or sink in the surrounding water,
without apparent effort, just as a Gold-fish rises or descends
by means of its swimming- oladder. There is no visible
outlet for the air thus confined in their interior, and the most
rigid scrutiny only shows a few delicate air-vessels of extreme
tenuity, in their immediate vicinity. Each of these air-sacs
consists of several coats ; of these the outermost, when feebly
magnified, seems of a uniform hue of jet-black ; but appears
under higher powers to be made up of numerous distinct
spots of black pigment, separated by considerable interspaces,
so as to give the organ a reticulated appearance ; and it is
only when this black pigment has been removed, together
with a dull opaque membrane, whereon the black patches
rest, that the real air-sac is displayed. When thus denuded,
the true wall of the air-sac appears to be composed of a dense
membrane, possessing great refractive power ; the effect of
which upon transmitted light is extraordinary. When highly
magnified, it is found to be entirely composed of numerous
coils of a delicate fibre, similar to that which maintains the
permeability of the tracheae of ordinary insects, arranged in
several superimposed layers, and having the appearance of
being closed on all sides. It is not until the larva thus con-
stituted has arrived at its full size that the appearances
described become complicated, by intermixture with organs
belonging to the pupa condition of the insect. At this period,
however, the rudiments of future limbs begin to show them-
selves under the form of transparent vesicles, which, as they
enlarge, crowd the thoracic region of the body.

The change from the larva to the pupa condition involves
several remarkable phenomena. The air-sacs, situated both in
the thoracic region and in the hinder portion, burst and un-

Rymer Jones, on Corethra plumicornis.

L03

fold themselves into an elaborate tracheal system ; and a pair
of ear-shaped tubes, of which not the slightest trace could
hitherto be discerned, make their appearance upon the dorsal
aspect of the thorax ; two long tracheae seem to be thus simul-
taneously produced, occupying the two sides of the body and
constituting the main trunks, from which large branches are
given off, to supply in front the head, the eyes, and the
nascent limbs ; while posteriorly they spread in rich profusion
over the now conspicuous ovaries, and terminate by ramifying
largely through the thin lamellae that constitute the caudal
appendages. The very act of this strange metamorphosis I
have not been able to witness under the microscope, owing
to the impossibility of predicating the exact period of its
occurrence — but there is reason to believe that it takes place
suddenly, and occupies but a short time in its completion.
In individuals subjected to microscopic examination within a
very brief period after their assumption of the pupa state, the
places originally filled by the air-sacs of the larva are found
to be occupied by the tattered remnants of their external
coats, clearly indicated by ragged membranes, covered with
patches of black pigment, in the immediate vicinity of which
I have invariably met with numerous air-bubbles, extrava-
sated as it were into the cellular tissue, as though forced out
by some leakage during the violent disruption of the air-sac.

I hope on a future occasion to lay before the Society a
series of drawings, illustrative of the minuter details con-
nected with this interesting process ; and, in case any of our
members should be induced to devote a portion of their time
to an investigation fraught with many difficulties, will at
present merely say a few words which may probably serve to
facilitate their operations, and save them much probation in
the expensive school of experience. In their fresh condition
these larvae are, from their very transparency, almost invi-
sible ; and such is the translucency of their tissues, that these
latter are with great difficulty distinguishable. To remedy
this inconvenience, I have tried the effect of dyeing them
with carmine and magenta, and of preserving them in a
variety of solutions, but with no satisfactory result. So im-
patient are they of endosmotic action, that they will not bear
the slightest increase or diminution in the density of the
surrounding fluid — at the touch of glycerine or syrup (how-
ever much diluted) they shrink up into a shapeless heap, and
by the weakest spirit are converted into masses of distortion.
At last, driven almost to despair by their perversity under
every mode of treatment, I was tempted to enclose them,
while still alive, in cells filled with their native element —

VOL. XV. i

104 Rymer Jones, on Corethra plumicornis.

pure water — and at once seal them up with a margin of gold-
size. In this condition I found that they would live for
several hours, and thus exhibit in perfection the action of
the heart, and the ganglionic bodies appended to its walls.
When this had ceased, I was enabled to study them for days
together, and found, to my great gratification, that they only
improve by keeping. Slowly their muscles assume a slight
. degree of opacity, and shrinking, as by a sort of rigor mortis ,
leave spaces through which the minutest details of their ana-
tomy are distinctly perceptible. The most delicate mem-
branes, by a similar process, are rendered sufficiently opaque
to be plainly visible, and the vesicles of the nascent limbs, in
specimens approaching the .pupa condition, become clear and
distinct. The nervous apparatus, constituting the ventral
series of ganglia, forms a very beautiful object : in specimens
thus preserved — the outer sheath, the structure of the ganglia,
the composition of the internodal cords, together with the
origin and course of the nerves, are all displayed in a most
satisfactory manner, even the cross-markings of the muscular
fibres are recognisable with the utmost distinctness. I have
here one or two specimens of these larvae thus prepared,
au naturel, which, although they have been upwards of a
year in their present condition, will, I doubt not, when
placed beneath the microscope, fully serve to recommend the
process I have adopted. There is one precaution necessary
in making these preparations, which, trivial as it may seem,
will be found of much practical importance. In order to
delineate specimens thus put up, while in the microscope, by
means of the camera lucida, it is essential that the depth of
the cells in which they are placed should be just such as to
press sufficiently upon the enclosed larva to hold it steady
while in a vertical position, otherwise it sinks in the sur-
rounding fluid, and is continually subject to displacement.
The manner in which I have succeeded in overcoming this
difficulty is very simple. The cells that I employ are discs
of thin sheet-lead, cut out with a circular punch, and per-
forated in the centre by another punch of smaller diameter.
These discs, when cemented to a glass slide with gold-size,
are easily rubbed upon a wet hone to the exact thickness
required, and the object so mounted retained in its place by
the pressure of the glass, will be found to be as steady and
manageable as if placed in Canada balsam.

105

07i Nachet’s Stereo-pseudoscopic Binocular Microscope,
and on Nachet’s Stereoscopic Magnifier; with
Remarks on the Angle of Aperture best adapted to
Stereoscopic Vision. By W. B. Carpenter, Esq.,
M.D., F.B.S., &c.

(Read June 12th, 1867.)

Nachet’s Stereo-Pseudoscopio Binocular Microscope. —
An ingenious modification of Mr. Wenham’s arrangement
has been introduced by MM. Nachet, which has the attri-

Fig. L

Arrangement of Prisms in Nachet’s Stereo-pseudoscopic Binocular: —
1, for Stereoscopic ; 2, for Pseudoscopic, effect.

bute, altogether peculiar to itself, of giving to the image
either its true Steoreoscopic projection, or a Pseudoscopic
“ conversion of relief,’’ at the will of the observer. This is ac-
complished by the use of two prisms, one of them (Fig. 1, a)
placed over the cone of rays proceed-
ing upwards from the objective, and
the other (B)at the base of the secondary
or additional body, which is here placed
on the right (Fig. 2). The prism a
has its upper and lower surfaces paral-
lel ; one of its lateral faces inclines at
an angle of 45°, whilst the other is ver-
tical. When this is placed in the
position 1, so that its inclined surface
lies over the left half (/) of the cone ot
rays, these rays, entering the prism per-
pendicularly (or nearly so) to its infe-
rior plane surface, undergo total reflec-
tion at its oblique face, and, being thus
turned into the horizontal direction,
emerge through the vertical surface at

right angles to it. They then enter the Nachet’s Stereo-pseudo-
vertical face of the second prism b ; and scopic Microscope.

106 Dr. Carpenter, on Stereoscopic Binoculars.

after suffering reflexion within it, are transmitted upwards
into the right- hand body, r', passing out of the prism
perpendicularly to the plane of emersion, which has such
an inclination that the right-hand or secondary body
(r, Fig. 2) may diverge from the left or principal body at a
suitable angle. On the other hand, the right half (r) of the
cone of rays passes upwards, without essential interruption,
through the two parallel surfaces of the prism a, into the
left-hand body ( l '), and is thus crossed by the others in the
interior of the prism. But if the prism A be pushed over
towards the right (by pressing the button «, Fig. 2), so as
to leave the left half of the objective uncovered, as
shown in position 2, Fig. 1, that half (/) of the cone of rays
will go on without any interruption into the left- hand body
(/'), whilst the right half (r) will be reflected by the oblique
face of the prism into the horizontal direction, will emerge
at its vertical face, and, being received by the second prism,
B, will be directed by it into the right-hand. body (r'). The
adjustment for the distance between the axes of the eyes is
made by turning the milled-head b (Fig. 2 ), which, by
means of a screw-movement, acts upon a movable chariot
that carries the prism b and the secondary body r, the base
of which is implanted upon it. Now, in the first\ position,
the two halves of the cone of rays being made to cross into
the opposite bodies, true Stereoscopic relief is given to the
image formed by their recombination, just as in the ordinary
arrangement. But when, in the second position, each half
of the cone passes into the body of its own side, so that the
reversal of the images produced by the Microscope itself is no
longer corrected by the crossing of the two pencils separated
by the prism a, a Pseudoscopic effect, or “ conversion of
relief,” is produced, the projections of the surface of the
object being represented as hollows, and its concavities
turned into convexities. The suddenness with which this
conversion is brought about, without any alteration in the
position either of the object or of the observer, is a pheno-
menon which no intelligent person can witness without
interest, whilst it has a very special value for those who
study the Physiology and Psychology of Binocular vision*

* The result of the numerous applications which the Author has made
of this instrument to a great variety of Microscopic objects, has led to a
confirmation of the principle of Pseudoscopic vision which he has stated
elsewhere — viz. that the readiness with which the conversion is effected
depends on the readiness of the mind to apprehend the converted form. Where,
as in the case of the saucer-like discs of the Arachnoidiscus , the real and
the converted forms are equally familiar, the “conversion” either of the
convex exterior or of the concave interior into the semblance of the other

Dr. Carpenter, on Stereoscopic Binoculars .

107

As an ordinary working instrument, however, this improved
Nachet Binocular can scarcely be said to possess any point
of superiority to the Wenham; whilst it must be regarded
as inferior in the following particulars : — First, that as the
uninterrupted half of the cone of rays (when the interposed
prism is adjusted for Stereoscopic vision) has to pass through
the two plane surfaces of the prism, a certain loss of light
and deterioration of the picture are necessarily involved ;
whilst, as the interrupted half of the cone of rays has to pass
through four surfaces, the picture formed by it is yet more
unfavorably affected; and second, that as power of motion must
be given to both prisms — to a, for the reversal of the images,
and to B for the adjustment of the distance between the two
bodies — a greater liability to derangement results than in
the simpler construction of Mr. Wenham.*

Nachet’s Binocular Magnifier. — Though the Author can
testify to the fidelity of the effect of relief obtainable by

Nachet’ s Binocular Magnifier, adapted to Beck’s Dissecting
Microscope.

the Binocular arrangement adapted by Mr. B. Beck

is made both suddenly and completely. In more complex and less familiar
forms, on the other hand, the conversion frequently requires time ; being
often partial in the first instance, and only gradually becoming complete.
And there are some objects which resist conversion altogether, the -only
effect being a confusion of the two images.

* This arrangement, like Mr. Wenham’s, can be adapted to any existing
Microscope ; and it seems peculiarly suitable to those ot French or German
construction, in which the body is much shorter than in the ordinary English
models. For in the application of the Wenham arrangement to a short
Microscope, the requisite distance between the eye-glasses of its two bodies

108 Du. Carpenter, on Stereoscopic Binoculars.

to his Dissecting Microscope,* he has found its utility to
be practically limited by the narrowness of its field of
view, by its deficiency of light and of magnifying power,
and by the inconvenience of the manner in which the eyes
have to be applied to it. An arrangement greatly superior
in all these particulars having been recently worked out by
MM. Nachet, the Author has combined the Optical part of
their Dissecting Microscope with Mr. R. Beck’s Stand, and
finds every reason to be satisfied with the result ; the solidity
of the Stand giving great firmness, whilst the size of the stage-
plate affords ample room for the hands to rest upon it. The
Objective in Nachet’s arrangement is an Achromatic combi-
nation of three pairs, having a clear aperture of nearly 3-4ths
of an inch, and a power about equal to that of a single lens
of one-inch focus ; and immediately over this is a pair of
prisms, each resembling a, Fig. 12, having their inclined
surfaces opposed to each other, so as to divide the pencil of
rays passing upwards from the Objective into two halves.
These are reflected horizontally, the one to the right and the
other to the left ; each to be received by a lateral prism cor-
responding to b, and to be reflected upwards to its own Eye,
at such a slight divergence from the perpendiculars as to give
a natural convergence to the axes when the eyes are applied
to the Eye-tubes, superposed on the lateral prisms — the dis-
tance between these and the central prisms being made
capable of variation, as in the Compound Binocular of the
same makers. The magnifying power of this instrument may
be augmented to 35 or 40 diameters, by inserting a concave
lens into each Eye-piece, which converts the combination into
the likeness (as originally suggested by Professor Briicke, of
Vienna) of a Galilean Telescope (or Opera-glass) ; and this ar-
rangement has the additional advantage of increasing the dis-
tance between the object and the object-glass, so as to give
more room for the use of dissecting instruments.

To all who are engaged in investigations requiring very
minute and delicate Dissection, the author can most strongly
recommend MM. Nachet’s instrument. No one who has not
had experience of it can estimate the immense advantage
given by the Stereoscopic view, not merely in appreciating
the solid form of the object under dissection, but also in
precisely estimating the relation of the instrument to it in

can only be obtained by making those bodies diverge at an angle so wide as
to produce great discomfort in the use of the instrument, from the neces-
sity of maintaining an unusual degree of convergence between the axes o.
the eyes.

* ‘ Transactions of the Microscopical Society,’ N. S., vol. xii, p. 3.

Dr. Carpenter, on Stereoscopic Binoculars. 109

the vertical direction. This is especially important when
horizontal sections are being made with tine scissors ; since
the course of the section can thus be so regulated to pass
through the plane desired, with an exactness totally un-
attainable by the use of any Monocular Magnifier.

On the Angle of Aperture best suited for Stereoscopic Vision.
— The Stereoscopic Binocular is put to its most advantageous
use when applied either to opaque objects of whose solid
forms we are desirous of gaining an exact appreciation, or to
transparent objects which have such a thickness as to make
the accurate distinction between their nearer and their more
remote planes a matter of importance. That its best and
truest effects can only be attained by Objectives not exceeding
40° of angular aperture, may be shown both theoretically and
practically. Taking the average distance between the pupils
of the two Eyes as the base of a triangle, and any point of
an Object placed at the ordinary reading-distance as its apex,
the vertical angle enclosed between its two sides will be from
12° to 15° ; which, in other words, is the angle of divergence
between the rays proceeding from any point of an Object at
the ordinary reading-distance to the two Eyes respectively.
This angle, therefore, represents that at which the two pic-
tures of an object should be taken in the Photographic
Camera, in order to produce the effect of ordinary Binocular
vision without exaggeration ; and it is the one which is
adopted by Portrait-photographers, who have found by expe-
rience that a smaller angle makes the image formed by the
combination of the pictures appear too flat , whilst a larger
angle exaggerates its projection. Now, in applying this
principle to the Microscope, we have to treat the two lateral
halves (l, r, fig. 4) of the Objective as the two separate
lenses of a double Portrait Camera, and to consider at what
angle each half should be entered by
the rays passing through it to form
its picture. To any one acquainted
wuth the principles of Optics, it must
be obvious that the picture formed
by each half of the Objective must
be (so to speak) an average or gene-
ral resultant of the dissimilar pic-
tures formed by its different parts.

Thus, if we could divide the lateral
halves or Semi-lenses l, r, of the
Objective by vertical lines into the
three bands a b c and a b' c ', and could stop off the two
corresponding bands on either side, so as only to allow

Pig. 4.

110 Dr. Carpenter, on Stereoscopic Binoculars.

the light to pass through the remaining pair, we should find
that the two pictures we should receive of the object would
vary sensibly, according as they are formed by the bands
a a' , b b' , or c c'. For, supposing the pictures taken through
the bands b b ' to be sufficiently dissimilar in their perspective
projections to give, when combined in the Microscope, a
sufficient but unexaggerated Stereoscopic relief, those taken
through the bands a a' on either side of the centre would be
no more dissimilar than two portraits taken at a very small
angle between the Cameras, and their combination would
very inadequately bring out the effect of relief ; whilst, on
the other hand, the two pictures taken through the extreme
lateral slips c c' would differ as widely as portraits taken at
too great an angle of divergence between the Cameras, and
their combination would exaggerate the actual relief of the
object. Now, in each of the bands b b' , a spot v v' may be
found by mathematical computation, which may be desig-
nated the visual centre of the whole Semi-lens ; that is, the
spot which, if all the rest of the Semi-lens were stopped off,
would form a picture most nearly corresponding to that given
by the whole of it. This having been determined, it is easy
to ascertain what should be the angle of aperture ( op q ,
fig. 5) of the entire Lens, in order that the angles v p v'
between the “ visual centres ” of its two halves should be 15°.
The investigation of this question having been kindly under-
taken for the Author by his friend Prof. Hirst, the conclu-
sion at which he has arrived is, that the angle of aperture of

the entire Lens should be about
36*6°. This, which he gives as
an approximate result only (the
requisite data for a complete Ma-
thematical solution of the ques-
tion not having yet been ob-
tained), harmonises most remark-
ably with the result of experi-
mental observations made upon
objects of known shape, with
Objectives of different angular
apertures.

When spherical objects, such
as the globular forms of Polycys-
tina or the pollen-grains of the
Malvaceae, are placed under a
Stereoscopic Binocular, provided
with an Objective of one half or four-tenths of an inch focus,
having an angular aperture of 80° or 90°, the effect of
projection is so greatly exaggerated, that the side next

Dr. Carpenter, on Stereoscopic Binoculars. Ill

the eye, instead of resembling a hemisphere, looks like
the small end of an egg. If, then, the aperture of such
an Objective be reduced to 60° by a diaphragm placed
behind its back lens, the exaggeration is diminished,
though not removed ; the hemispherical surface now
looking like the large end of an egg. But if the aper-
ture be further reduced to 40° by the same means, it is at
once seen that the hemispheres turned towards the eye are
truly represented ; the effect of projection being quite ade-
quate, without being in the least exaggerated. — Hence it may
be confidently affirmed — alike on theoretical and on practical
grounds — that when an Objective of wider angle than 40° is
used with the Stereoscopic Binocular, the object viewed by
it is represented in exaggerated relief, so that its apparent
form must be more or less distorted.

There are other substantial reasons, moreover, why Objec-
tives of limited angle of aperture should be preferred (save in
particular cases) for use with the Stereoscopic Binocular. As
the special value of this instrument is to convey to the mind a
notion of the solid forms of objects, and of the relations of their
parts to each other, not merely on the same but on different
planes, it is obvious that those Objectives are most suitable to
produce this effect, which possess the greatest amount of pene-
tration or focal depth ; that is, which show most distinctly,
not merely what is precisely in the focal plane, but what lies
nearer to or more remote from the Objective. Now, as
increase of the angle of aperture is necessarily attended with
diminution of penetrating power, an Objective of 60° or 80°
of aperture, though exhibiting minute surface-details which
an Objective of 40° cannot show, is much inferior in suit-
ability .to convey a true conception of the general form of
any object, the parts of which project considerably above the
focal plane or recede below it.*

The Author would further draw attention to two important
advantages he has found the Stereoscopic Binocular to
possess, his own experience on these points being fully

* In accordance with these principles, the Author has caused Messrs.
Powell and Lealand to construct for him an Objective of half-inch focus
with an angular aperture of 40°; and he has found it to answer most
admirably for the purpose for which it was intended — the examination of
Opaque objects with the Stereoscopic Binocular. For not only are these
represented in their true forms, but the relations of their different parts
are seen with a completeness not otherwise attainable. And an Objective
so constructed has this great advantage over one whose originally larger
aperture has been reduced by a diaphragm — that the distance between its
front lens and the object is so much greater, as to admit far more con-
venifntLy of side illumination.

112 Dr. Carpenter, on Stereoscopic Binoculars.

confirmed by that of others. In the first place, the pene-
trating power or focal depth of the Binocular is greatly
superior to that of the Monocular Microscope ; so that an
object whose surface presents considerable inequalities, is
very much more distinctly seen with the former than writh
the latter. The difference may in part be attributed to the
practical reduction in the Angle of aperture of the Objective,
which is produced by the division of the cone of rays trans-
mitted through it into two halves ; so that the picture received
through each half of an Objective of 60° is formed by rays
diverging at an angle of only 30°. But that this Optical
explanation does not go far to account for the fact, is easily
proved by the simple experiment of looking at the object in
the first instance through each eye separately (the prism
being in place), and then with both eyes together ; the dis-
tinctness of the parts which lie above and beneath the focal
plane being found to be much greater when the two pictures
are combined, than it is in either of them separately.

In the absence of any Optical explanation of the greater
range of focal depth thus showed to be possessed by the
Stereoscopic Binocular, the Author is inclined to attribute it
to an allowance for the relative distances of the parts which
seems to be unconsciously made by the Mind of the observer,
when the solid image is shaped out in it by the combination
of the two pictures. This seems the more likely from the
second fact to be now mentioned, namely, that when the Bino-
cular is employed upon objects suited to its powers, the pro-
longed use of it is attended with very much less fatigue than is
that of the Monocular Microscope. This, again, may be
in some degree attributed to the division of the work
between the two eyes ; but the Author is satisfied that unless
there is a feeling of discomfort in the eye itself, the sense of
fatigue is rather mental than visual, and that it proceeds from
the constructive effort which the Observer has to make, wTho
aims at realising the solid form of the object he is examining,
by an interpretation based on the flat picture of it presented
by his vision, aided only by the use of the Focal Adjustment,
which enables him to determine what are its near and what
its remote parts, and to form an estimate of their difference
of distance. Now, a great part of this constructive effort is
saved by the use of the Binocular, which at once brings before
the Mind’s eye the solid image of the object, and thus gives
to the Observer a conception of its form usually more com-
plete and accurate than he could derive from any amount of
study of a Monocular picture.*

* It has happened to the Author to be frequently called on to explain

113

Dr. Carpenter, on Stereoscopic Binoculars .

the advantages of the Binocular to the Continental (especially German)
savans who -have not made themselves acquainted with the instrument.
And he has been struck with finding that when he exhibited to them objects
with which they had previously become familiar by careful study, and of
whose solid forms they had already attained an accurate conception, they
perceived no advantage in the Stereoscopic combination ; seeing such objects
with it (visually) just as they had been previously accustomed to see them
(mentally) without it. But when he has exhibited to them suitable objects
with which they had not been previously familiarised, and has caused them
to look at these in the first instance monocularlyy and then stereoscopically ,
he has never failed to satisfy them of the value of the latter method, except
when some visual imperfection has prevented them from properly appre-
ciating it. He may mention that he has found the wing of a small Butterfly,
having an undulating surface, on which the scales are set at various angles
instead of having the usual imbricated arrangement, a peculiarly appropriate
object for this demonstration ; the general inequality of its surface, and the
individual obliquities of its scales, being at once shown by the Binocular,
with a force and completeness which could not be obtained by the most
prolonged and careful Monocular study.

INDEX TO TRANSACTIONS.

VOLUME XV.

A.

.Ecistes, on two new species of the
genus, by Henry Davis, E.R.M.S., 13.

Address of the President for 1866—
67, by James Glaisher, 25.

Anniversary Meeting of Royal Micro-
scopical Society, 22.

Auditors’ report, 2-1.

B.

Beale, Lionel S., on nutrition from
a microscopical point of view, 75.

„ „ on the germinal

matter of the ovarian ova of the
stickleback, 85.

Binocular microscopes, by W. B. Car-
penter, M.D., 105.

Brown, J. H., on an iris diaphragm,
74.

Browning, John, notes on the spectra
of a dichroic fluid, 71.

Bye-Laws and Charter of the Royal
Microscopical Society, 7.

C.

Carpenter on binocular microscopes,
105.

Cetacean teeth, on some fossil, by E.
Ray Lankester, P.R.M.S., 55.

Charter and Bye-Laws of the Royal
Microscopical Society, 7.

Colour in organised substances, by
J. B. Sheppard, M.R.C.S.E., 64.

Condenser, double hemispherical, for
the microscope, by the Rev. J. B.
Reade, P.R.S., 2.

Corethra plumicornis, on the metamor-
phosis of the larva of, by Prof.
Rymer Jones, 99.

VOL. XV.

Crystallisation of the sulphates of
iron, cobalt, and nickel, by Robert
Thomas, 19.

D.

Davis, Henry, on two new species of
the genus J3cistes, 13.

Diaphragm eye-piece for the micro-
scope, by Henry J. Slack, 1.

Dichroic fluid, notes on the spectra of
a, by John Browning, E.R.A.S., 71.

G.

Germinal matter of the ovarian ova of
the Stickleback, by L. S. Beale,
M.B., P.R.S., 75.

Glaisher, James, President’s address,
25.

Gregariniform parasite of Borlasia, by
W. C. McIntosh, M.D., E.L.S., 38.

H.

Haddock, remarks on the parasites in
the nerves of the common, by R.
L. Maddox, 87-

I.

Iris diaphragm proving the circular
form whether expanding or con-
tracting, by J. II. Brown, Esq., 74.

J.

Jones, Rymer, on the metamorphosis
of the larva of Corethra plumicornis,
99.

L.

Lamps for the microscope, on two
new, by Ellis G. Lobb, P.R.M.S.,
72.

k

116

INDEX TO TRANSACTIONS.

Lankester, E. Hay, on some fossil
cetacean teeth, 55.

Lobb, Ellis G., on two new lamps for
the microscope, 72.

M.

Maddox, R. L., on the parasites in
nerves of the common haddock, 87.

McIntosh, W. C., on the gregarini-
form parasite of Borlasia, 38.

N.

Nutrition, on, from a microscopical
point of view, by S. Beale, M.B.,
&c., 75.

O.

Opaque illumination, on a form of
slide for, by Samuel Piper, 18.

P.

Parasites, on, found in the nerves of
the common haddock, by B. L.
Maddox, M.D., 87.

Piper, Samuel, on a portable slide
cabinet and form of slide for opaque
illumination, 16.

Portable slide cabinet, on a, by Samuel
Piper, 16.

R.

Reade, J. B., on a double hemispheri-
cal condenser for the microscope,
2.

S.

Sheppard, J. B., on colour in organ-
ised substances, 64.

Slack, H. J., on diaphragm eye-piece
for the microscope, 1.

Slide, on form of, for opaque illumi-
nation, by Samuel Piper, 18.

Sulphates of iron, cobalt, and nickel,
on the crystallisation of, by Robert
Thomas, 19.

T.

Tadpole, on the changes which accom-
pany the metamorphosis of the, by
W. U. Whitney, Esq., M.R.C.S.,
&c. &c., 43.

Thomas, Robert, on the crystallisation
of the sulphates of iron, cobalt, and
nickel, 19.

Tomkins, J. Newton, on a travelling
microscope, 20.

Travelling microscope, on a, by J.
Newton Tomkins, P.R.C.S., F.S.S.,
E.R.M.S., 20.

Z.

Ziphius Sowerbiensis, on the structure
of the tooth of, by E. Ray Laukes-
ter, E.R.M.S., 55.

PRINTED BY J. E. ADLARD, BARTHOLOMEW CLOSE.

Iuffen~West3c.

TCT/est irao

TRANSACTIONS OF THE ROYAL MICROSCOPICAL
SOCIETY OF LONDON.

DESCRIPTION OF PLATE I,

Illustrating Mr. Davis’s paper on Two New Species of the
Genus (Ecistes , Class Rotifer a.

Fig.

1. — (Ecistes intermedins, lateral aspect, x 130.

2. — „ „ young specimen, with disc retracted.

3. — „ „ ventral aspect.

4. — „ „ dorsal aspect.

5. — „ longicornis , ventral aspect, x 210.

6. — „ „ dorsal aspect.

7 & 8. — „ „ extremities of antennae, showing setae attached

to the pistons. More highly magnified.

9. — Sheath of (E. intermedins , the upper part constructed with carmine.
10. — „ (E. longicornis, „ „

TRANSACTIONS OF THE ROYAL MICROSCOPICAL
SOCIETY OF LONDON.

DESCRIPTION OF PLATE II,

Illustrating Dr. McIntosh’s paper on the Gregariniform
Parasite of Borlasia.

Fig.

1. — The gregariniform parasite from Borlasia odoculata. X 200 diam.

2. — Do. do. from one of the long examples from Devon, x 350 diam.

3. — Outline of one of the parasites after prolonged immersion in water.

4. — Curious structures extruded with the parasites under pressure from

B. odoculata. x 350 diam.

5. — Parasitic ovum, x 350 diam.

6. — Gelatinous cord, with ova in situ . X 180 diam.

vm.

- • ' r. t - '

o’ > V .

w

4

tj ' i'-' 1

■

•TX

'd#''

■'V : V

Siltf

• ; ’

■

w

- ,U> , ■

— \

W.C.M. iel. Tnf£en"West

W.'West imp

tissm s

WU Whitney del |T."West sc.

Yr West imp.

'W.TJ.Whitn.ey del. T.'West sc.

"VfWest chnnp.

SffatfJ.JIxo'Joc. %t.XV.N5 M/}

TRAN SAC TIONS OF THE ROYAL MICRO-
SCOPICAL SOCIETY.

DESCRIPTION OF PLATES III & IV,

Illustrating Mr. Whitney’s paper on the Metamorphosis
of the Tadpole.

PLATE III.

Fig.

1. — The young tadpole (enlarged view) within the capsule of the egg.

2. — The tadpole (enlarged view) twenty-four hours after birth, exhibiting

nostrils, mouth, suckers, and external gills.

3. — The tadpole, life size, as seen by the naked eye, on the fourth or fifth

day after birth, with the outer gills in full development.

4. — The young tadpole (enlarged view), exhibiting the outer gills, with the

digital-like tufts of the incipient inner gills, and the pair of minute
tubes below the heart, which are the incipient lungs of the future
frog.

5. — The tadpole, life size, as seen by the naked eye, when the outer gills

are disappearing.

6. — The tadpole (enlarged view) with the outer gills nearly removed ; the

operculum closed on the right side, but permanently open on the left ;
the digital tufts enlarging.

7. — Exhibits the crests of the inner gills in the more advanced stage, and

the progressive development of the lungs at the same period.

8. — Simple loop of blood-vessel as seen in the second stage of the inner

gill (fig. 12), and the tortuous shapes afterwards seen in the crests
of the third stage.

9. — Enlargement of the vessel connecting the afferent and efferent trunks

of the inner gill.

10 — “The waning tadpole and incipient frog.”

11. — View of the lungs as seen on one occasion through the back of a tad-
pole.

PLATE IV.

12. — Internal gill of the tadpole, in its second stage.

13. — Internal gill, fully developed, exhibiting the crests and vascular system.

14. — The vascular connection of the external with the incipient internal

gills.

15. — Exhibits the lungs of the young frog, with the right lung in a state of

vascular injection.

16. — The heart, systemic arteries, pulmonary arteries and veins, and lungs

in the full-grown frog. In the right hand figure the heart is turned
up to show the junction of the pulmonary veins, and their point of
entrance into the left auricle.

TRANSACTIONS OF THE ROYAL MICRO-
SCOPICAL SOCIETY.

DESCRIPTION OF PLATES V & VI,

Illustrating E. Ray Lankester’s paper on tlie Structure of
the Tooth in Ziphius Sowerbiensis ( Micropteron Sower -
biensis, Eschricht), and on some Fossil Cetacean Teeth.

PLATE VJ
Fig.

1. — Part of a transverse section of the upper part of the tooth of Microp-

teron Sowerbiensis , in the University Museum, Oxford, c, Cement ;
g, globular matter, with interglobular spaces ; d , dentine ; o-d , osteo-
dentine.

2. — Portion of another section, a little nearer the base ; letters as before.

3. — Cement of the same tooth ; natural size of lacunae, 3£gth — T3Mth of

an inch, a, Small longitudinal lacunae.

4. - — "Dentinal tubules emerging from the opaque globular mass, with its

interglobular spaces or dentinal cells.

PLATE VI.

1. — Tooth of Micropteron Sowerbiensis , natural size, a b, Line of the

alveolus.

2. — Longitudinal section of the same, a, Line of microscopic sections ;

d , dentine; o-d, osteo-dentiue ; g, globular matter; c, cement,

3. — Half of a transverse section ; letters as before.

4. — Osteo-dentine of a fossil tooth.

5. 6. — Osteo-dentinal cavities of fig. 4 in section ; natural size, Ath— ^5th

inch.

^.JLcMMWJSm

EB. .Lank-ester del. TuffeifWestsc.

"WLVest imp.

ERi.tmad. iWestso.

WTWest rmp

TRANS. MIC. SOC. VOL. XV. N. S. PL. VII.

OVARIAN OVA. — STICKLEBACK.

SHOWING GERMINAL MATTER COLOURED WITH CARMINE.

Fig. 1.

Free germinal vesicle, its
spots unchanged. After
Dr. Ransom.

Pig. 2.

Free germinal vesicle, of which, the wall
is raised at one part, showing the ' colloid
mass.' After Dr. Ransom.

Pig. 3.

Fig. 4.

Ovarian ovum, with large germinal
vesicle. The yolk cracked and form-
ing fissures radiating outwards.

x 100.

Pig. 5.

Germinal spots from a ruptured germinal vesicle.
X 550. The ovum was -fg inch in diameter, and
the germinal vesicle 5^0 ■

Germinal spot3, with new centres (nucleoli)
within them, and more minute germinal spots
in the intervals between them. X 550.

Pig. 7.

Fig. 6.

Germinal vesicle, showing ger-
minal spots all over the surface.

X 215.

Fig. 9.

Most minute ovarian ova under-
going development, in the midst of
a delicate tissue with cells.

X 550.

Fig. 8.

Supposed section of germinal
vesicle, showing germinal
matter throughout.

Fig. 10.

Globules of yolk, with germinal matter
(nuclei). Advanced ovarian ovum
X 215.

Extremely small germinal spots.

X 1700.

1000th inch , , x 215.

„ „ , , x 550.

> > > > i i

x 1700.

L. S. B., April, 1367.]

Jnmi.Jl^tfK.Vd.WEZSL. m.

Maddox ctal.etpkoto. Tu££e&West sc.

W. West, imp.

TRANSACTIONS OF THE ROYAL MICRO-
SCOPICAL SOCIETY.

DESCRIPTION OF PLATE VIII,

Illustrating Mr. Maddox’s paper on a Parasite from Caudal
Nerves of the Haddock.

1. — A portion of nerve with cysts ; the displacement of the nerve-fibres is

well shown.

2. — One of the parasites contracted and partially covered with cyst con-

tents.

3. — Parasite released from a cyst and in a state of progression ; the integu-

ment is seen to be covered with short spines, beautifully arranged.

4. — Parasite, dorsal aspect. po,p o', p o, p o' = vibratile organs, probably

connected with a water-vascular system.

These four figures X 40 diameters.

5. — Portion of caudal nerve packed with cysts, x 25 diameters.

6. — Parasite released from a cyst, x 40 diameters.

Figs. 5, 6, from photographs ; the former obtained in seven seconds by
artificial illumination with magnesium wire, the latter in fifteen minutes by
paraffin lamp-light.

TRANSACTIONS OF THE ROYAL MICROSCO-
PICAL SOCIETY.

DESCRIPTION OF PLATE IX,

Illustrating Professor Rymer Jones’s paper on the Structure
and Metamorphosis of the Larva of Corethra plumicornis.

Fig.

1. — Larva of Corethra plumicornis representing the general arrangement

of the viscera, and the position of the air-vesicles, sketched under the
compressor, and magnified sixty diameters.

2. — Pupa of Corethra plumicornis as seen under the compressor shortly

after its change from the larva condition. The air-vesicles have
disappeared, the anterior pair having been converted into the respi-
ratory tubes — O' O'. The now largely developed tracheal system
seems to be entirely derived from the disruption of the two pairs of
air-vesicles, the lacerated remains of which may be seen scattered
throughout the cavity of the body and adhering in the shape of
small patches of black pigment to the walls of the lateral tracheae.
The ganglionic nervous system of the dorsal vessel is largely developed,
and the masses composing the ventral series of ganglia of great pro-
portionate dimensions. From the opacity of the thoracic region it
was impossible to see whether any changes had occurred in the con-
1 dition of the proventriculus and muscular gizzard.

3. — Represents the head and apparatus of jaws of the larva of Corethra

plumicornis as seen uuder the compressor, magnified about 200
diameters. The proventriculus is inverted and protruded from the
mouth together with the muscular gizzard /, and the narrow tube gt
whereby the latter viscus originally communicated with the ventricular
portion of the alimentary canal; a nervous plexus, and a few gan-
glionic centres are seen in the muscular walls of the proventriculus.
The same letters of reference indicate corresponding parts in all the
three figures.

1. — 1st pair of oral appendages.

2. — 2nd pair of ditto

3 — 3rd pair of ditto

4. — 4th pair of ditto

5. -— 5th pair of ditto

PLATE IX. — continued.

6. — 6th pair of oral appendages.

7. — Auxiliary spikes, situated beneath the mouth.

a. — Encephalic masses of the nervous system.

b. — Conglomeration of eyes.

c. — Ocellus detached from the principal organs of vision.

d. — Ventral chain of nervous ganglia.

e. — Pro vent riculus.
f — Gizzard.

g. — Slender canal leading from the gizzard to

h. — Ventricular portion of alimentary canal.

i. — Pylorus and insertion of

k. — Hepatic csecal tubes.

l. — Small intestine.

m. — Large intestine.

n. — Anal aperture.

o— Air-vesicles, subsequently converted into O' dorsal respiratory tubes,
and

p. — Tracheal system.

q. — Dorsal vessel, to the different compartments of which are appended

r. — Nervous ganglia of the heart.

s. — Rudimentary ovaries.

t. — Nerves and ganglionic masses in the muscular walls of the proventri-

culus.

# «,

Date Due

OCT 16 W