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K4896

NOTICE.

The Council of the Ray Society regret tliat the illuess
of their artist, Mr. Wing, and other circumstances, have prevented
the publication of the last part of Messrs. Alder and Hancock’ s
work on the Nudibranchiate Mollusca, and tlie second volume
of Mr. Darwin’s work on the Cirripedes. These, with the last
volume of the Bibliography, are now in the press, and will
shortly be issued together.

The volume now sent, ‘ Botanical and Piiysiological
Memoirs,’ is part of the issue for 1853.

22, Burlington Street;

April 12//;, 1854.

THE

KAY SOCIETY.

INSTITUTE D MDCCCXL1V.

LONDON.

MDCCCLIII.

BOTANICAL AN!) PHYSIOLOGICAL

MEMOIRS,

CONSISTINQ 03?

I.— THE PIIENOMENÖN OF REJUVENESCENCE IN NATURE,

ESPECIALLY IN

TI1E LIFE AND DEVELOPMENT OF PLANTS.

BY DR. A. BRAUN.

TRANSLATED BY A. HENFREY, F.R.S., ETC.

II.— ON THE ANIMAL NATURE OF THE DI ATOMEN,

WITH AN

ORGANOGRAPIIICAL REVISION OF THE GENERA

ESTABL1SHED BY KUTZINO.

BY PROFESSOR G. MENEGHINI.

TRANSLATED BY CH RI STOP HER JOHNSON, M.R.C.S.E.

III.— AN ABSTRACT OF THE NATURAL HISTORY OF PROTOCOCCUS

PLUVIALIS.

BY DR. FERDINAND COHN.

BY GEORGE BUSK, F.R.S., ETC.

F.DITED BY

ARTHUR HENFREY, F.R.S., F.L.S.

LONDON:

PRINTED FOR TUE RAY SOCIETY.

MDCCCLIII.

WELLCÜ i r INSTITUTE

LIBRARY

Coli.

we'ViQmec

Call

No.

W~, “

J. E. ADLARD, PRINTER, BART H01-0MEW CLOSE.

CONTENTS.

l'AQJi

On the Phenomenon oe Rejuvenescence in Nature . . J

„ Animal Natuke of the Diatomeje . . . 3-13

„ Natuhal Histoky of Protococcus pluvialis . . 515

REFLECTIONS

ON

THE PHENOMENON

REJUVENESCENCE IN NATURE

ESPECI ALLY IN

THE LIFE AND DEVELOPMENT OF PLANTS.
By Dit. ALEXANDER BRAUN,

PROFESSOR OF BOTANY IN THE UNIVERSITY OF BERLIN,

&C. &C.

(Leipsic, 1851.)

TllANSLATED BY

ARTHUR HENFREY, F.R.S., F.L.S., etc.

TO THE READER.

The present Treatise * On the Phenome non of Rejuvenes-
cence in Nature, especially in the Life and Development
of Plants,’ was issued to a small circle in May of last
year, from the High School of Ereiburg, in the Breisgau,
to whicli the Author at that time belonged, and for which
it was especially composed, as a Prorectorate Address ;
its pubhcation to wider circles of the Scientific world
has been delayed by many circumstances, partly connected
with the change of residence of the Author, through his
call to the High School of Giessen ; partly in consequence
of the events which afflicted the country with dissensions,
and obstructed the calm progress of scientific undertak-
ings. Nevertheless, the Author hopes that the substance
of the Essay, which contains an attempt to combine the
special branches of Botanical research more intimately
together and with the entire body of Science, by means
of certain connecting ideas, and to grasp and t.race out
the old questions under a new point of view, has not
meanwhile grovvn out of date, so that he may venture to
comply with friendly requisitions from many quarters, and

X

PREEACE.

deliver over bis little work to more general diffusion.
May the reader receive it kindly, as a little nail in tbe
great structure which Natural Science has to erect, to
wbich eacb labourer seeks to add bis contribution in bis
own way, and to work for which, witb voice and pen,
is tbe endeavour, tbe life, and tbe happiness of tbe
Naturalist

THE ATJTIIOR.

Giessen; Fcbruary, 1851.

Since tbe original of tbis work was published, tbe
Autlior bas been cbosen to succeed the late Professor
Link in tbe University of Berlin ; and now occupies a
Position commensurate witb bis numerous and elaborate
contributions to Science. Modestly as he speaks of tbis
remarkable work, the Translator bas no besitation in
designating it one of the most important of modern con-
tributions to tbe Philosophy of Botany. Without enter-
ing into tbe discussion of tbe curious speculations
indicated in the title, attention is especially to be called to
tbe lucid exposition of the Morphology of Plants, and to
tbe definite establishment and full illustration of the laws
of this brancli of botanical Science ; to tbe section upon
Cell-formation, again, which constitutes a body of fact
and theory of tbe utmost importance to Physiology,
Animal as well as Vegetable, since, bringing together
and completing tbe various recent publications on tbe

PREFACE.

XI

subject of cell -development, it clearly demonstrates the
necessity of reforming the older views of tlie character of
cellular structures, and, in showing the incontestible
evidence now existing as to the essentially primary nature
of the cell-contents or protoplas mic structures, at once
levels the new field of investigation in Plants, and affords
a basis for the Clearing up of the analogies existing
between the Animal and Vegetable tissues.

The Translator has confined himself to a careful
rendering of the text and a slight amplification of the refer-
ences, especially in cases where English translations exist
of the works quoted. To have revised, in aecordance
with the present condition of knowledge, certain of the
speculations which are now a little out of date, would
have been interfering too far with the Author ; but the
sources are indicated whence the more recent facts may
be obtained.

London ; September, ]853.

A. H.

SUMMARY OF THE CONTENTS.

PAGE

Pheface : Origin and object of the Treatise, with addenda to certain

special parts . . . . . ix

Introduction : Reflections on the appearance and the essential Nature
of Itejuvenescence in general; passingto the Phenomena of Reju-
venescence in Plants, more particularly, divided into three sections 1

i. Formation of Sprouts as the means of Rejuvenescenee of the

Vegetable stock . . . . .21

1. Individual nature of the Sprouts . . .23

2. Formation of sprouts as subordinate reproduction, and alter-

nation of generations of the plant caused thereby . 24

a. Origin of sprouts . . . .25

b. Deficiencies of them . . . .28

c. Complementary conditions . . .32

d. Distinction of essential and inessential sprouts . 36

e. Importance of the latter in reference to

a Character . . . .38

ß Economy of Vegetable life . . . 41

f. Transitional cases . . . .43

ii. Leaf-formation, giving rise to the subdivisions of the Rejuvenes-

cence in the single sprout . . . .51

1. Phenomena of Rejuvenescenee in the sprout through retro-

gressive and vibratory course of the Metamorphosis . 52

2. The ascending Metamorphosis considered in its risings and

sinkings . . . . .60

a. Summary of the Leaf-formations . . 62

b. Change of proportionate breadth of the base of the

leaf in the different leaf-formations . . 67

c. The samein the longitudinal development of the leaf . 70

d. Disappearance of leaf-formation in particular regions . 83

3. The individual leaves as links of Rejuvenescenee in the course

of Metamorphosis .... 101

XIV

CONTENTS.

PAGE

a. Criticism of Schultz’s doctrine of the Anaphyta of

the plant . 2Q2

b. Criticism of E. Meyer’ s and otlier vicws of the building

up of the plant out of leaves ; and also of Steenstrup’s
view of the Alternation of Generations in the plant 106

c. Relation of the stem to leaf-formations . .108

Explained by the examination of the fundamental

organs of the plant . . , p()9

d. Course of formation of the leaf . . . ]]2

e. Obscrvations on Phyllotaxy . . .116

m. Cell-formation, constituting the innnediate focus of the pheno-
mena of Rejuvcncscence .

1. Formation of the Cell, generally

a. Departurc of the plant and of the Vegetablc kingdomfrom

the simple cell ....

a. Uuiccllular plants in the different senses of the
term ....

ß. Graduated succession of Multi-cellular plants .

b. The single cell, examined by itself .

a. The various mcanings of the word Cell
ß. Membrane and contents of the Cell
y. Cells without membrane
5. Coat of the contents (primordial utricle) .

«. Eurther subdivision of the contents
i. Nucleus .....

2. Destruclion of the Cell, a preparatory condition to its llcju-

venescence .....

a. The Ccll-membrane ....

a. Dissolution of this

а. Through tearing

ß. Through complcte pceling (Skinniug of the cell)
y. Escape of the Rejuvcnescent cell from the
old coat (demonstrated more particularly in
the active gonidia of the Algen )

б. Examples of imperfect liberation of gonidia

b. Softening and Solution of the Cell-membrane

b. Processes of Destruction in the contents of the cell 195

a. Solution of Starch . . . .196

b. Disappearance of Fat . . . . 202

Caused by previous desiccation . . 205

(Illustrated by the history of Chlamidococcus and

Chlamidomonas) .... 205

121

123

124

124

130

155

155

155

156
156
169
174

176
176

177
177
ISO

182

187

189

CONTENTS.

XV

PAGE

c. Relation of these phenomena to the interchange of

substances in animals . . .217

d. The nocturnal respiration of plants . . 219

e. The pkenomenon of Rejuvenescence of the Cell in

its relation to the periods of the day . . 221

3. Reconstruction ofthe Cell, considered as a process of Rejuve-

nescence ..... 226
Kind and degree of Reconstruction :

a. Reconstruction without division of the cell . . 229

b. With division into two Daughter-cells . . 232 '

(Different descriptions of this byMohl, Unger, and Nägeli) 233

a. Division by gradual constriction (confirmed in Spi-

rogyra) ..... 237

b. Division with simultaneous (?) limitation over the

whole plane of division . . . 247

b*. Reconstruction with division into two cells, one remaining
as an unchanged Mother-cell, the other cut off as a
Daughter-cell (cell-formation by constriction). . 250

c. Reconstruction with division into four Daughter-cells . 254

Connection of this with halving . . .256

d. Reconstruction with division into an indefinite number of

Daughter-cells .... 259

1. Ry division of contents filling the whole cavity of the

cell . . . . .259

2. By division of alayer of contents investing the wall of
the Mother-cell (explained specially in Hydrodictyon ) 261
Connecting case .... 271

e. Partial Reconstruction through formation of Daughter-cells

inthe contents of theindependentlysurvivingMother-cell 272

1. The Daughter-cells produced close upon the cell- wall 272

2. The Daughter-cells formed free in the contents . 274

a. Formation of a free Daughter-cell around the pri-

mary nucleus of the Mother-cell . . 275

b. Formation of free Daughter-cells around secondary

nuclei .... 276

a. Formation of the germinal vesicles of the Pha-
ncrogamia . . . .276

ß. Of the transitory cells in the embryo-sac . 278

y. Of the endosperm cells . .278

S. Cascs of abnormal cell-formation . . 281

4. Appendix, on the union of previously separate Cells (Con-

jugation) ...... 281

XVI

CONTENTS.

PAGE

Attempt to classify tlie nunierous kinds of Conjugation :

a. Conjugation of Sirailar cclls, with tlie subordinate modifi-
cations ..... 284
n. Conjugation of Dissimilar cells . . . 296

Excluded cascs ..... 298

Concluding Reflections ..... 305
Connection of tlie Rejuvenescencc of tlie Individual with tliat of
thc Species ..... 306

a. Examination of thc rcproduction of tlie Mosses and Eerns

in reference to this .... 308

b. The formation of Yarieties, in its rclation to tlie history of

tlie Individuals and of the Species . . . 311

c. Examination of Ilybrids (with a particular description of

thc bchaviour of Ci/tisus Adarni ) . . . 316

2. Analogous ascent in thc higher systematic divisions, from

the species to the genus, family, order, dass, &c. . . 322

3. llcjuvcncscence as universal Phenomenon of the courscof De-

velopment. of Nature, in detail and as a whole, as tlie expres-
sion ofa constantlyre-awakencd recollection of thc inherent
Vital Purpose ..... 324

Explanation of tue Plates .... 327

Index ....... 337

ADDENDUM. At page 9, line 5, insert after

“ Rheum with C, outer, sliorter, and 3 inner, longer;” “in Polygonnm
with !i, outer, shorter, and 3 inner, longer.”

P RE FA CE.

The idea Garried out in the following treatise, namely,
of grouping together the phenomena of the graduated
Organisation of plants, and those of their reproduction,
linder a common point of view, as processes of Rejuvenes-
cence, and of subjecting them to a minute examination
under this point of view, was awakened in my mind several
years ago, through an investigation of Hydrodidyon, and
aroused anew at the end of that autilran of 1848 through
the discovery of the mode of reproduction of Pedicistrum,
a genus of most elegant little Algse, wliich are still
included by many authors in the Animal Kingdom. At
the Annual meeting of our local Association for the ad-
vancement of theNatural Sciences, on the 4th of December
of the same year, I endeavoured, in a public lecture,
apropos to the description of the course of formation and
reproduction of the genus of Algse just named, to develope
this idea, and to show that it is the power of Rejuvenes-
cence which principally distinguishes organic from inor-
ganic existence, since it is to this that we must ascribe,
both the graduated progression of the development of the
individual organism, and the repetition of individuals
by reproduction. When in the spring of last year, the
confidence of my colleagues, and the grace of liis Royal

b

XV111

PREFACE.

Highness tbe Grand-Duke, the most serene Rector of
our Iiigb School, conferred the Prorectorate npon me, I
determined to make this subject, whicli appeared botli
capable of a profound treatment and of general interest,
the basis of the Introductory Programme whicli, in
accordance with the good old custom, the Prorector
delivers in honour of the birthday of the exalted Patron
and Rector of the High School, our beloved native
Prince. The main thoughts were soon arranged, and
the outlines traced ; the illustrative examples added to
the text were to be worked out durin g the printing of
the essay, and the natural history of some of the genera
of Algoc more particularly remarkable in reference to the
subject, ( Pcdiastrum , Characium , Hydrodictyon , As-
cidium, Sciadium , Palmoglcea, &c.) was to begiven in an
appendix. But the storm of the reyolution, whicli broke
out in May, and sliook our blessed fatherland to the
very foundations of its existence, soon interrupted the
incipient labours ; for our High School ivas threatened
by the tempestuous waves, and it was at the cost of care
and severe effort alone, that the threadsof scientific activity
were protected from total disruption in the midst of
the session. But, in the ever-memorable days of July,
when the fermenting elements of social dissolution, whicli
we at length saw gathered within our walls, had vanished
before the helpful Brother-hand, strong in the spirit of
Order, like the shades of night before the sun’s light ;
when in the following month our beloved ruler was
enabled to return to his blinded people, who, ungrateful
for his beneficence, had risen in Opposition to him ; the
season was too far advanced, for the projected discourse
to be properly carried out in time, on the basis whicli

PREEACE.

XIX

had been previously laid down. Consequently, to avoid
offering anything hasty and unworthy of the High School,
and yet to avoid withdrawing this essay from the des-
tination to which it had been as a labour of love devoted,
there remained nothing eise, but to make it follow the
invitation to the celebration of the Royal birthday, as a
subsequent secondary tribute. The reasons why it has
been delayed until now, lie partly in the manifold re-
tardations through current official duties, and partly in the
nature of the subject itself, which claimed more time
and space in the elaboration of the details, than could be
guessed in the original project. For, in the publica-
tion of phenomena as yet little known, the examples
cited could not well be mentioned without an exact
account of personal observations, which rendered neces-
sary repeated diffusive episodes, in which both the vo-
taries of the Morphology and Anatomy of Plauts, and
Physiologists in particular, will find many novelties.
Where I have dependecl on the observations of others,
the sources are conscientiously mentioned ; I connected
wit.h this point also the design, to point out to the young
who are just entering the realms of Science, who, more-
over, were especially kept in view throughout the whole
exposition of the cliosen subject, the authors who cleserve
confidence, and from whose writings may be cliscerned,
not only the present state of Scientific Botany, but the
Problems growing out of this, which will next require
to be solved. I had greatly clesired to be able to add
numerous illustrative plates to this treatise, but I have
omitted doing so, in order to avoid further delaying its
publication. For the same reason I am obliged to give
up, for the present, the appendix which formed part of

XX

PREFACE.

the original plan, and which is referred to more than
once in the text ; a separate treatment of this will the
sooner enable me to publish, with a certain degree of
completeness, my observations on the natural history
of various fresh-water Algse, in particular on many genera
belonging to the debateable region between the Veget-
able and Animal Kingdoms, as well as those that
produce active gonidia.

After tliese remarks, which may explain the delay in
the appearance of these pages, I feel compelled to add
a word of justification in reference to the direction of the
researches which form the basis of the following obser-
vations, and which will doubtless be regarded in many
quarters as antiquated, and leading away from the strict
scientific path. A vivid conception of Nature, such as
is here attempted, which tries to find in natural objects,
the expression of living action, and not merely the eflects
of dead forces, does not lead, as some think, to baseless
air-castles, for it does not set itself to study the life of
nature, in any other way than in its revelation through
phenomena; and just as little does it exclude rigid in-
vestigation of the laws, governing all natural phenomena ;
for it is exactly by the investigation of the laws within
which, and the forces through which life acts, that it
hopes to arrive at a perception of what is given to life,
according to the difference of its stages. The justification

of the effort to comprehend all the phenomena of nature,
not only in their external reactions, but also in their
inner connection, as the data for an universal history of
living nature, lies in the very nature of the human soul,
in its connection, not merely external but inward and
essential, with living nature. As the study of nature

PREFACE.

XXI

originally arose from the feeling of the intiraate relation-
ship between externa! nature and human nature, it is
also its aim to grasp and bring to perception, the fur-
thest depths of this connection.

Partly during the printing of these pages, partly after
its conclusion, I met with various literary novelties, of
which I could have wished to have availed myself in
passages on which they bore, in particular, Mettenius’s
‘ Beiträge zur Botanik’ (Heidelberg, 1850), in which
occurs an exact description of the discovery of spermato-
zoids in Isoetes, mentioned cursorily at page 144 from
information derived from a letter from the author.*
Gaertner’s important work, on the Production of hybricls in
the Yegetable Kingdom, ( Die Bastardzeugung im Pflan-
zenreich, Stuttgart, 1849), first reached me after my ob-
servations on Cytisus Adami, p. 316, were printed. There
is no absolute decision there even, whether this remarkable
intermediate species is a hybrid, procluced by fertilisation
from Cyt. Laburnwn, and C. purpur eus, or not; on the
other hand various notices on the same subject had been
published, which I had overlooked, especially the informa-
tion of Schnittspahn’s paper, in the thirdYear’s publication
of the Horticultural Society of the Grand-duchy of Hesse,
{Mitth. des Gartenvereins im Grossherz. Hess., Darmstadt,
1842, p. 38,) that Adam obtained his plant, by budding
C. purpur eus upon C. alpinus. \ During the first year
the grafted buds remained undeveloped, but many ine-
qualities of the surface displayed themselves around

* These points are further referred to in editorial notes. — A. H.

t This probably means C. alpinus, Lamk., the same as C. Laburnum , L.,
and not C. alpinus, Mill., for the C. Adami of gardens returas on all hands
into C. Laburnum, L., and not into C. alpinus, Mill.

XXII

PREEACE.

them, which were gradually clevelopcd into buds, and these
were developed in the second year into shoots, all bnt
one of which, were C. purpureus. This one shoot had
grown much thicker, and exliibited a form intermediate
between C. alpinus and C. purpureus ; this shoot was the
parent of the C. Adami of gardens. Unfortunately, this
report does not state from wliat sonrce H. Schnittspahn
himself derived his knowledge of these circumstances at-
tending the origin of C. Adami. Since C. Adami possesses
undoubtedly the nature of a hybrid, if Sclmittspahn’s
information be correct, this plant will furnish the ex-
traordinary case of a hybridation in a vegetative way,
(conceivable as occurring throngh a fertilising action of
the cells of the graft upon the primitive cell of an adven-
titions bud,) and its return into the two parent species,
within the vegetative rcgion, wonld then correspond to
the vegetative origin. That hybridation is not in any
way unusual in the genus Cgtisus, is proved by a mag-
nificent hybrid, between C. purpureus and C. elongatus,
which is now, wliile I write these lines, in most beautiful
blossom in the Botanical garden of our Iiigh School.
It was obtained from thebrotliers Banmann of Bollwiller,
in whose catalogue for 1847, it is given as “ C. purpureo-
elongatus (nobis), une nouvelle hybride superbe.” In
form and hairiness of the leaves it resembles C. elongatus ;
in the form of the calyx, more C. purpureus. The colour
of the flowers is a mixture of light-yellow and pale rose-
red, the Standard being of the latter colour, the wings
and keel of the former ; when withered or dry, the red
colour becomes stronger and almost like that of Cytisus
Adami. The blossoms keep fresh a long time, but set no
fruit. Messrs. Baumann were kind enougli to furnish

PliEFACK.

XX111

me, by letter, with the following particulars concerning
the origin of this fine hybrid. “Our C. purpureo-elowgatus
was produced from our own sowing, but not by means
of artificial fertilisation ; the mother of this plant is C.
elongatus, from wliich we gathered the seeds ; but near
this stood a C. purpur eus, and probably the hybrid was
produced by insects conveying the pollen from the latter
plant to the former. We have never observed in this
plant such a change of form as occurs in C. Adami
After all this, we look with so much the greater impa-
tience for positive elucidation, basecl on repeated experi-
ments, of the mode of origin of C. Adami , and in this
for the establishment of several most important physiolo-
gical facts. In regard to the return of Cgtisus Laburnum
quer cif olius, into the common Laburnum with entire
leaflets, mentioned at p. 315, I shall only mention here,
in addition, that I have observed the sarne phenomenon
lately in the Botanic garden of this town, and here the
transition to the parent species took place by a marked
Separation from the variety and not through graduated
intermediate stages.

Since this Preface is at the same time a PostScript, and
as regards the first part of the Treatise a tolerably late one,
it affords an opportunity of adding a few more comple-
mentary observations on the subjects touched upon in
the text. In the first place, in regard to the mode of growtli
of the Yine, described at p. 46, I must report that the
examination of fresh seedlings obtained last autumn,after
that passage had been printed, did not confirm the con-
jecture expressed in the note, that the seedlings would
behave like root-suckers ; for they were totally devoid of
tendrils at the summit, and displayed in the axils of the

XXIV

PREFACE.

ordinary leaves, resting buds, which had two bud-scales,
and therefore resembled,in tbis respect, not the “Geitzen,"
but tbe “ Lotten The derivation of the “ Lotten ’ from
the “ Geitzen ” in the way described, does not occur
until the later degrees of ramification.

To the examples mentioned in the note, p. 114 of Fern
leaves, with the apex of the leaf constantly undeveloped, or
onlyunrolled after long interspaces and in steps, belongs
also the genus Neurolepis, the larger species of which, re-
lated to N. exaltata , develope their slender pinn ate leaves,
which often attain a length of 4 or 5 feet, in several
annual stages or lengths, which are marked in the deve-
loped leaf as contracted places, furnished with shorter
pinnae. In N. neglecta , Künze., the commonest species
of our gardens, I found four such sections, of which,
however, two often appear to be developed in one year.
With tliis mode of development is connected the fact
that the leaves of the species of Neurolepis ordinarilyexhibit
a little rolled-up knob at the end, and only rarely their
proper leaf-point, running out into a terminal pinna.

I have to give a short postscript to the natural history
of the Chlamidomonada, relating to the “resting stage” of
Chlamidomonas tingens (p. 215). The said species
appeared in great abundance tliis spring in little rain
pools, close to the town, colouring the water briglit green.
When the “ rest” commenced, the cells collected together
in pulverulent, partly floating masses, exhibited a
globular form, a diameter of from to ^ of a millim.,
granular-punctate, green contents, and one larger vesicle.
When the pools dried up in the month of May, crust-
like, pale brick-red coats were found on the ground, the
cells, formerly green, having assumed a pale reddish

PREFACE.

XXV

colour, thc vesicle at the sarae time becoming indistinct,
while the remainder of the contents became coarsely
granulated, (through the formation of oil?). The plants
have remained in this state ever since, not altering even
when the pools were refilled by rain. The resting, but
still green condition, seemed to me to correspond to
Protococcus Felisii , Kütz., that which had turned red
through desiccation, to Pr. Orsinii, Kütz., at least, ac-
cording to the specimens sent to me by De Brebisson
as a small variety of that species.

Herewith, I deliver these pages to the Fathers of our
High School, my honoured colleagues, with the petition
for a friendly reception, as a memorial of the efforts and
expansions in Science and in Life, we have shared in an
eventful year ; I deliver it to the Academic Youth, in
the hope that they may find therein the threads which
connect the separate fragments of knowledge into a
whole, and that the perception of this connection may
encourage them to follow, with double zeal, undistracted,
through good and evil times, the study of the material
so abundant in all branches of Science, and thus to enter
more and more into the sacred workshops, in which are
hewn the stones for building the great Dome of human
knowledge. To the wider scientific public, lastly, I
delivei these pages, with the consciousness of having
therein published many results of conscientious research
which will find their place in the building of Science,
even if the connection in which I have liere souglit to
place them, should shape itself very differently in a
future, higher stage of development of Natural History

Dr. A. Braun.

Freibürg, Briesgaü; May, 1850.

X.

CONSIDERATIONS

ON THE

PHENOMENON

OF

REJUVENESCENCE IN NATURE,

ESPECIALLY IN

THE LIEE AND DEVELOPMENT OE PLANTS.

Scientific investigation of thelaws of Organic Nature
advances, in our times, in two distinct directions, one of
which may be called the physiological, the otlier the
morpliological. Each, followed in a one-sided manner,
lias led to multiplied contradiction in theory, which
can only be solved by a more profound biological method
of contemplation. Both directions hasten towards a pro-
founder coraprehension of this kind ; the former in a
negative manner, since, considering vital phenomena only
in their external physical conditions, it is led, at the
conclusion of every investigation, to a ground of the
phenomenon inexplicable on this side ; the latter in the
positive way, since, regarding the forms, in connexion
with the history of development, as becoming, changing
and passing away, it must recognise a specific and indi-
vidual vital unity, running through all the changes of
form, unless the temporary products of development are
to dissolve away into inessential appearance, and to lose
all internal connexion. The investigation of development,
in the smallest, as in the largest circle, is, therefore, the

1

2

THE PHENOMENON OE

most profitable and raost promising field of action in
natural history ; and the remarks otfered liere belong
to tliis field, for they discuss a general question which
is not foreign to any special history of development.

Among the most essential and general characters of
every course of development of a natural object, are com-
mencement and term, and, connected with these, youth and
age. Youth and Age, although fallin g within the sphere
of ordinary human direct experience of life, do not appear
to me, in reality, so easily or simply comprehensible in
their true meaning and their contrasted relations, as
might seem from a mere abstract consideration. Answers
to the questions, so readily presenting themselves — How
are youth and age distinguished ? Wlien does youth
ceasc, and age begin ? How do they pass into one
another? Which is the more perfect condition of life?
— would pcnetrate deeply into the interconnection existing
among the totality of cosmical ideas. The purpose of the
present Essay only extends to a few reflections, based on
experience, on the changing relation of youth and age in
the course of the life-time of the individual.

Youth and age are not mere periods of time, into
which life may be divided so as to allow us to say, — Youth,
ceases liere and Age begins ; and one does not pass
gradually and continuously into the otlier, so that youth
decreases in the same ratio as age increases ; a glance
into life rathcr demonstrates to us that thephenomena of
youth go through life side by side with those of age, in
the most varied conditions of exchange, not merely pre-
senting themselves sinmltaneously in various departments
of life, but crowding into the same region, and contending
there. Even the child has old teeth, destined to early
destruction (the milk-teeth), and young teeth (wisdom
teeth) appear even at a late age. Many organs have
already become old and lost their vitality before birth,
such as the gills of the Mammalia, the teeth of the
whale* &c. ; lizards and snakes form a young skin

* See Stannius, ‘Lebrb. der Vergleich. Anatomie,’ p. 411, on tbe teetb

REJUVENESCENCE IN NATURE.

3

annually, tbrowing off the old one ; the crab changes even
bis old stomach for a young one, every year. The
cotyledons, and even tbe radical leaves, as tbey are termed,
bave already yielded to age in tbe (Enothera , tbe rape,
and many otber plants, at a time when tbe flowers still
remain in a young condition of buds, and, on the other
band, tbe floral envelopes bave perisbed when tbe fruit
is onlv in the commencement of its process of rnatura-
tion. In tbe pupa of tbe grasshopper, all tbe external
organs are fully developed, at a time when the wings are
just beginning to be formed. So may Man be a mere
cbild in mental development, when already old in bodily
respects. We see youth and age, therefore, presenting
tbemselves alternately in one and tbe same course of
development ; we see youth break forth in age, and enter
into tbe midst of tbe process, for tbe purpose of com-
pleting or metamorpbosing tbe structures. This is the
pbenomenon of Rejuvenescence (Verjüngung), which is
repeated in infinitely varied ways in all domains of life,
but nowhere asserted more distinctly and more accessibly
to investigation, than in the Vegetable kingdom. With-
out Rejuvenescence tbere can be no progressive develop-
ment ; only the lifeless creation, or ratber, that dying in
tbe moment of production, the mineral, is devoicl of the
power of Rejuvenescence ; whence it is also deprived of
development and propagation.

Rejuvenescence appears, in tbe first place, as a return
to an earlier condition of life, whereby is obtained a point
of departure for renewed progress ; or, in tbe extreme
case, as a retrogression to tbe commencement of tbe
entire course of development, to attain tbe aim in a repe-
tition of the development. The former we see in tbe
Rejuvenescences of tbe individual within tbe course of its
individual development, tbe latter in tbe Rejuvenescence
of tbe species througb tbe succession of individuals. Tbe
retrogression just mentioned, introducing tbe Rejuve-

in the foetus of the whale. According to Eschericht the fcctus of Baleenop-
lera lonrjirnana has 102 teeth in the upper, and 81 in the lower jaw.

4

THE PHENOMENON OF

nescence, is either morphological, the structure returning
actually from a higher stage into a lower formation ; as
we see, for example, in annual Rejuvenescence of many
herbaceons perennials {plant re redivivat), as also in most
woody plants, in the buds, whicli commence the rejuve-
nised course of life witli leaves of the lowest stage of
formation, the bud-scales belonging to the “catapliyllary”
{nieder -blatl) formation ;* or the retrogression is merely
physiological, a Chemical decomposition and dissolution
in the structure already existent, whereby this becomes
capable of a Rejuvenescence of its form, combined with a
more or less distinct metamorphosis. Such it is in the
interchange of materials in animals, with whicli are con-
nected their more gradual and imperceptible, as well as
the more sudden and surprising transformations. That
the like is not wanting in plants, will be demonstrated
in the succeeding examination of the phenomena of
Rejuvenescence in Cell-life.

We have consequently to distinguish a descending and
an ascending direction in the Rejuvenescence, one retro-
gressive, the other advancing with new impetus, one
undoing the old and existent, the other shaping out the
new. Both directions are necessarily related to that
renewal of the vital movement to whicli we have applied
the term “ Rejuvenescence,” and it is their alternation
whicli maintains life in Vibration and guards it against
untimely rest. The smaller the vibrations in whicli it
occurs, the more constant will the formative process
appear to be, as for example in the processes completing
the structure of a cell not destined to division ; but even

* There arises great difficulty in rendering these terms applied to tlie
different Orders of leaves, since we have none corresponding to them in
Englisli. They are so frequently used, not only in a substantive but au
adjective way, both in this treatise and in other recent German works, and
have such a definite meaning, that we venture to invent new words and to
use them in this translation. The word “ nieder-blatt,” (lower leaf), signifying
cotyledons, the bud-scales at the base of branches, or the scales ol rhizomes,
is rendered by cataphyll; “ laub-blatt,” (leafy-leaf), stem leaves generally, by
euphyll; “ hoch-blattp (high leaf), leaves belonging to the inflorescence, by
hysophyü. — A. TI.

REJUVENESCENCE IN NATURE.

5

liere the lamellar deposition of the coat of the cell betrays
the internal Vibration of the formative activity. On the
other hand, the phenomena of Rejuvenescence appear so
much the more striking and surprising, the deeper the
depression of life preceding the new upraising ; and the
more distinct, consequently, the Separation of the new
lease of life from the old, the more perfect the con-
sumption and breaking through of the old structure by
the new. The metamorphoses of insects furnish raost
beautiful examples.

Inquiring into the causes of the phenomena of
Rejuvenescence, we recognise that external Nature, amid
which special life displays itself, acts in calling and awaken-
ing through the influences which the seasons of the
year, nay even the hours of the day, bring forth; but the
proper internal cause can only be founcl in the tendency
towards completion, which is present in every existence
according to its kind, and drives it to subordinate to itself
ever more completely the foreign and external world, to
shape itself within it, as independently as the specific
Nature allows. At the same time, however, a term
is set to the task, beyond which the phenomena of Re-
juvenescence do not proceed. As in mental life there is
a time of maturity, when youtli and age are as it were
intermingled, when the restless strife of acquisition and
destruction ceases, when motion is paired with rest, so
also in the physical and corporeal there is an analogous
condition of maturity and relative rest, when the alterna-
tion of destruction and reformation is only carried on
in the small vibrations of the interchange of material,
maintaining vital motion and guarding against its being
benumbed. In animals we see this condition com-
mence when the organism has attained completion, is
<cgrown-up” as it is called, when nothing more new is
formed, but the actually existent enters upon its predes-
tined function, into its Service in the more elevated side of
animal life. In Vegetable life we see the correspondin g
phenomenon in the fruit, which Aristotle alreadyregarded as

6

THE PHENOMENON OF

the aim of the formative activity of the Plant. With it is
closed the series of structures, in the graduated production
of which the plant runs througli its metamorphoses ; in it
vegetable life comes to a peaceful conclusion, yet without
the internal vital movement stopping at the same time with
the cessation of external growth, for it is not so inde-
pendent and permanent in any other part of the plant as
in the ripening fruit. At this stage of development,
therefore, in comparison with the preceding process, rest
comes at the end, but at the same time, according to the
relation to a higher sphere of life, the activity lying in
the destination of the final form.

If we compare the structures of the earlier stagcs of life
with the condition of the final forms, we see that in tliem
also exists a ])ause, an effort at conclusion, which, however,
has to be renounced before the development can advance
towards its tcrm. In Opposition to such fixation at
subordinate stages, which would become arrests of
development, comes the active power of Rejuvenescence,
spinning onward the threads of development with new
lengths. Thus it is in every single creature which has a
development at all, that is in every living thing. But
we may give this rcflection a wider expansion.

The term reached by the mdividual, is not the last term
of development for the greater complex of the wliole, nay
the individual itself indicates this totality in its depen-
dance. The individual existences of Nature are links
in the development of that Kingdom of Nature to which
thcy belong, and in the widest sense, links in the develop-
ment of the totality of natural life. Hcnce the phenomena
of Rejuvenescence present tliemselves not only in the
individual existence, but connect tliemselves again on all
hands with the term of the individual existence, going
beyond this, constantly renewing living Nature in her
individual members, and thus bearing up and carrying
her onwards to her final purpose. To the fruit adjoins
itself the seed as the commencement of a new individual
course of development, just as the production of future

REJUVENESCENCE IN NATURE.

7

generations is connected with the maturation of the
animal organism.

Against tliis general relation, howcver, of the phe-
nomena of Rejuvenescence to progressive development,
may be raised the objection that the cases of Rejuvenes-
cence last mentioned, on which depend propagation of
natural bodies, are, in point of fact, very different in this
respect from those first spoken of, those occurring within
the cycle of the individual development ; in the one case
the aim of the Rejuvenescence would be a progress in the
development, while in the other it would be a mere repe-
tition of the like, as is distinctly demonstrated by the invari-
ability of species in the Animal and Yegetable kingdoms.
Yet this distinction vanishes when we test the gradations
of the cases, on both sides, and particularly if we rise above
the narrow field of vision of the present, in our examina-
tion of reproduction. The appearance of like alone being
repeated in nature, is removed in looking back from our
present stationary time into former epochs of the world.
There we find really the first beginnings of the species,
the genera, nay even of the Orders and classes of the Vege-
table and Animal kingdoms ; we see at a glance how more
or less profound transformations were connected with the
appearance of the higher stages of the Organic Kingdoms,
so that genera and species of the ancient world disappeared
again, while new ones took their places. But through all
this change are expressed not mere accidental revolutions
of the earth, on the one hand of destroying, on the other
laying the basis of new soil for the flourishing progress
of organic life, — but far rather definite laws, penetrating
into the very details of the development of organic life.
Thus, for example, among the Vertebrate series the Fislies
appear first, tlien the Amphibia, and, subsequent to both,
Birds and Mammalia. The Fishes of the first periods, as
fish the lowest of their dass,* resemble in many respects
the Amphibia, more indeed than the fish subsequently
appearing, of higher Orders, from the very circumstance

* Agassiz. Pomons fossiles, Introduotion, xxx.

8

THE PHENOMENON OE

that the types of the individual classes were less distinct
in the first representatives ; the special character of the
dass, which is ever more d istinctly impressed in the suc-
ceeding series of Fishes, not yet being fully developed.
Equally remarkable is the relation of the first Mammals
of the earth, the celebrated Marsupialia of Stonesfield,*
to the dass Mammalia generally. The Marsupialia (in-
cluding the Monotremata) stand, as is well known, below
all Mammalia, nearest to the oviparous animals of the pre-
ceding classes, the Birds and Fishes, and not merely in
regard to the strncture of the Organs of generation. but
also in that of the brain ; while, on the other hand, they
adjoin in tlieir external form, in the structure of the
extremities and the teeth, the higher Orders either of the
Herbivorous or the Carnivorous series, the Rodentia and
the Ferse. We thus see again here the character of the
dass imperfectly represented in the beginning, and the
subsequently diverging series of the dass United even
to indistinctness. In the geological occurrence of the
separate sections of tlie Invertebrate animals, also, we
find the developmental connexion many times confirmed,
m that a determinate fundamental type appcars first in a
few simple forms, then in the course of epochs the
n umber and multiformity of the representatives increase
more and more, tili finally, when the series of forms is
developed to its extreme term, it often suddenly vanishes
again from nature, or lcaves but a few representatives
beliind. One of the most remarkable examples of this
kind is presented by the family of the Ammonites.f

* Phascolotherium BucJclandi, and Thylacotheritm Prewstü, Owen. Yide
Buckland, ‘Mineralogy andGeology,’ i, 72.

f The transition period possesses the single genus of the family of
Ammonites, the Goniatites, the trias period the genus Ceratites, the Jurassic
age 11 sections of the genus Ammonites , the clialk period 11 sections of the
same genus, 10 of which are peculiar, and besides these the genera Crioceras,
Ancyloceras, Scaphites, Hamites , Ptychoceras , Baculites, Turrilites, and
Helicoceras, all of which occur exclusively in tlie chalk formation, with the
exception of Ancyloceras, of which genus the Jura formation already possessed
species. Then the family of the Ammonites vanishes totally. See Leopold
von Buch on Ammonites , and D'Qrbigny, ‘ Paläontologie Frainjaise,5 i, 433.

REJUVENESCENCE IN NATURE.

9

The Vegetable kingdora of tlie ancient world likewise
exhibits a periodical progress corresponding to a gradation
of structure still existing, since tlie oldest periods have
exhibited scarcely anything but Flo werless plants (Crypto-
gamia), which are soon followed by the Gymnosperras
(Cycadaceae and Coniferae), and in sorae degree by still
doubtful Monocotyledons, while the Dicotyledonous plants
appear distinctly latest. The results of geological re-
search appear to confirin, more and more, that all this
progress of organic nature, frorn the first onset to our
own time, has an essential connexion, and, although dis-
turbed in many ways by the catastrophes which the
earth has suffered, has never been altogether interrupted ;
in a word, that it represents a single history of develop-
ment, and not a series of separate and independent
creations.

The ancient changes in the living garment of the earth,
appear then as Rejuvenescences of organic nature in mass,
and the individual genera and species of the organic
kingdoms as subordinate links in its great chain of
development. The fact that nature halted at determinate
points, in the calm intervals, and during the epochs pro-
duced, essentially at least, only the like, does not remove
the relation to the totality of the development. This is
the same phenomenon, on a grand scale, as when we see
the plant repeat itself in the same form, often hundreds
of times, at particular stages of its growth, before the
metamorphosis advances to a new stage, as for example,
often hundreds, or even thousands, of the ordinary
(euphyllary) leaves [Erica, Cattuna, Tamarix Abies), bracts
(hypsophyllary leaves) ( Bipsacus , Cnicus, Celosia), petals
(NymjjJuBa, Mesembryanthemum, Illicium ), stamens (Pa-
paver, Dittenia, Uelleborus), or carpels (Myosurus,
Anemone, Anona ), are formed in unbroken succession on
one and the same axis. But even in these times of
halting, by no means the absolutely like is formed. No
leaf, even when belonging to the same formation, exactly
resembles another ; and with every successive leaf, if the

10

THE PHENOMENON OE

development advances as far as the terminal blossom, the
plant approaches one step nearer the fonnation of the
flower. Neither are the individuals of the same species
exactly alike ; and the capability of developing certain
sets of varieties testifies the developmental power of the
species, even within the restriction to the specific type.

We cannot, therefore, ignore a certain relation to the
development of the great whole, even in those phenomena
of Rejuvenescence which continue the series of individuals
in what seems a liiere repetition of the like. Tliis rela-
tion speaks most meaningly in the highest region of the
whole graduated series of Nature, whcre the development
passes over from the physical into the spiritual. Who
would deny the relation of the production of new genera-
tions to progressive development, in the field wliere it
lies nearest to us, namely, in the Human Race? The
condition of humanity in tliis respect falls within the
spliere of our contemplation, for the aim to which the
infinite Rejuvenescences throughout all Nature strive,
through the attainment of which our period of creation
is distinguished from all the ancient epochs, is the very
existence of Man, towards whom Nature points, from step
to step, ever more distinctly throughout her entire series ;
and Man again cannot bc considered without t.liat which
itself constitutes his humanity, the development of Mind.
The development of Mind cannot be separated from its
substratum Nature, since although Mind itself is destined
to rise victorious over all the obstructions of physical life,
it must also penetrate backwards through all the stages
of that life, and give them a spiritual signification.
Only by starting from tliis standing point, fixing the
aim of the entire development in Nature, can we find the
true internal connection of all the gradations of natural
life, and by the very conjunction with the course of
development of Man, Natural Iiistory acquires its highest
import. As Nature without Man presents externally
only the image of labyrinth without a clue, scientific
examination which denies the internal spiritual founda-

REJUVENESCENCE IN NATURE.

11

tion of Nature, and its essential connection with
Mind, leads only to a chaos of unknown matters and
forces,* that is of matters and forces wkick are sealed
books to the mind, or more properly of unknown causes
wkich co-operate in a manner to us inexplicable. From
this dark chaos no bright path leads up to the mind ;
nay, it is inconsequent to regard the mind from this
point of view as anything but an inessential result of the
co-operation of unknown causes. The study of develop-
ment is pre-eminently calculated to defend us from such
a miserable spoliation of Science, for the connection of
the perceived phenomena of Being must necessarily lead
us to the recognition of the Becoming , as an internal
essence (specifically) the same through all changes.

The comprehension of the individual phenomenon as a
member of a series of essential correlative representations,
requires not merely the carrying back of the research to
the earliest rudiment, from which alone the succeeding
transformations can obtain their correct Interpretation,
but also a continuation of the observation up to the term
of the development, whereby is first perceived, on the
other hand, the true destination of the efforts in the
formative processes. This is equally true of individual
organs, whose physiological destination is first distinctly
realised when the formation is complete, and of the indi-
vidual whole, whose specific and generic charaeter is
chiefly expressed in the last stage of the metamorphosis,
— for example, in the flower and fruit of the Plant. This
is true, moreover, of the more comprehensive develop-
mental series in Nature. The charaeter of every genus,
family, dass, &c., should grasp its type, as it were its
ideal object, for which purpose the lower members of the

* The sadness of such an essence-less view of nature, which of course raust
strive to eradicate from the ideas and language of soicnce, all which from its
own standiug point appears anthropomorphic, does not strike us in its
fulness, simply from the fact that the desired cradication cannot be so readily
carried out, on account of the intimate and immemorial biending of the
more profound ideas with human language. Sec Schleiden, ‘ Die Pflauze
und ihr Leben,’ 15. ‘The Plant,’ translated by A. Hcnfrey.

12

THE PHENOMENON OF

series are always less fit than the higher, in which it is
stamped more plainly and corapletely. Thus in the
Ornithorynchus the type of the Mammal is so iraperfectly
and aberrantly represented, that doubt could long exist
whether it belonged to the series of the Mammalia at all,
and the flowers of the Cycadese are so little like a flower,
that it was only after much comparative study that the
conviction was arrived at, that these plants actually belong
to the commencement of the series of Flowering plants
(Phanerogamia). If we apply this mode of examination
to Nature as a whole, as the developmental series in-
volving all the subordinate series, if we here also seek the
solution of the problem, at the term of the development,
we are most distinctly directed to the completion of the
development ofMind as the destination of the whole pro-
cess, bccoming visible at the highcst stage of natural life.
The mind which becomes developed in Man, is not fitted
together, with the physical organism, from without, for we
bchold its evolution indicated in the lower stages of
natural life, especially in the Animal kingdom ; the
spiritual life is rather the purest and most refined repre-
sentative of the fundamental life, which we meet as
natural life in the preceding stages. We may say of
Mind , that it is the youngest, and yet the oldest , existence
in nature, destined to attain in its last age, its eternal
youth, the freedom fitted to its essential nature. Rising
from the groundwork of Nature bearing and supporting
them, the spiritual Rejuvenescences in thehistory ofMan
strive towards this aim of internal vital emancipation,
driving the mind out of every senility, every fetter of
time, to soar upward in a new flight of life.

Thus is our own history connected with the history
of Nature. The thought of Rejuvenescence in Science,
Church and State, now again moves nations, and
meets us in the most varied efforts, in ways Crossing one
another in manifold directions. As yet, alas, we have
become acquainted almost solely with the negative side
of these efforts, the Destructive ; but in the eyes of the

RUJUVENESCENCE IN NATURE.

13

naturalist this dissolution woulcl tend merely to indicate
the proximity of the transitiou to a new, upgrowing time
which will seize the Positive, in all fields, more pro-
foundly, and give it a more perfect shape. Will this
hope be fulfilled? Has not Old Europe rather arrived
at a hoary age, and an approacli to its dissolution?
The ans wer to this must be written first of all in our
own hearts; but if you would seek it externally, look
with the eye of the naturalist into the hidden worksliops
of the future, and you will find an infinite abundance of
germs and buds, which bear the promise of a rieh future
within thern ; you will above all find them in the domain
of Science, as the highest region of mental development,
from which alone the latest reformations of life can and
ought to issue. But these are digressions leading us too
wiclely from the purpose of the foregoing considerations.
If however it be true that all the domains of life are parts
of a great total development ; if it be true that every de-
partment of Science leads in its more profound establish-
ment to the same eternal idea, which is the foundation of
all reality and all truth, — each department must be
mirrored in the others, and thus the naturalist may be
permitted to contemplate each movement of the human
life which surrouncls him, in the mirror of Nature; to
find in whose lawfully connected government, the key to
calm judgment, is often his gain and payment.

In the preceding observations we have sought to regard
the phenomenon of Rejuvenescence in its general, exter-
nal mode of appearance, and to mark out the wide fielet
in which it is repeatecl in such a multifold and yet es-
sentially always the same way. A profound investigation
into the nature of Rejuvenescence would pre-require
somewhat minute research into the essence of age and
youth. A few more remarks upon youth may be per-
mitted here. According as we regard life as a mere
result of external causes, or cliscover its basis in one
original internal endowment, will youth appear to us, in
the one case as poverty, want, and crudity, in the other

14

THE PHENOMENON OF

as the yet undivided fulness and strength of the unde-
veloped existence, as superabundant wealth of energy,
striving to unfold itself. These two modes of considering
the question occur, for example, in application to the
earliest, youthful stages of the Human Race ; thus we find
on the one side the doctrine of the origin ally animal con-
dition of Man, according to which Man, scarcely distin-
guishable from apes, probably of black colour, perhaps
even sought after bis nourishment on all fours or climbing,
devoid of art, language and thought ; then gradually dis-
covered speecli through imitation of natural sounds, and
as it were accidcntally; and was only led through external
necessity, not through internal impetus, through the com-
bat witli external nature which his extraordinary defence-
lessness and helplessness brought upon him, to each
flight upward of life in art and civilization, upbuilding
all progress from without, not unfold ing from w ithin.
In Opposition to this representation Stands the doctrine
of the paradisaical condition of the first Man, who at his
first appearance stood face to face witli obedient Nature,
as Lord, as completeMan and likeness of God, urged by
the fulness within to give outward sliape in word and
work to his inborn divine ideas. Wlien we acknowledge
both the internal and external, in their co-operation in
life, we shall casily be able to unite these two views, that
is if we disregard the exaggerations on the one side, and on
the other the mythical imagery (which represents the inner
potentiality as the external actuality.) The insufficiency
of the first view, which logically carried out entirely dis-
owns anything internal and essential in natural phe-
nomena, may be shown us, if, as was referred to above,
we do not find it in our own life, or are disinclined to
draw conclusions from that as to life outside us, by the
instinct of animals, in which is revealed so great an
abundance of gifts, not given from without, but un-
doubtedly inborn, as the gift of song, the impulses to art,
or to migration, &c. The phenomena of mental life in
animals, which we ascribe to Instinct, have been correctly

REJUVENESCENCE IN NATURE.

15

compared with wliat has been called, in the material
sphere, tlie specific formative impulse, or typical force.
Instinct is the continuation of the formative impulse in
a higher sphere, as is particularly clearly manifest in the
phenomena of the constructive impulse, in the formation of
envelopes and clothing ( Serpula , Phyyanea, Psyche ), nests
and dwellings, as a kind of ulterior and more external
material Organisation. The specific formative impulse,
however, is not an outwardly derived direction of the
activity, but one inwardly contained, acting, from internal
causes, as inner determination and force. This is shown
by the fact, that under like external conditions of exist-
ence, the organism shapes itself in a peculiar, specific,
nay even individual way, in each creature, whence the
multiformity of the picture which every mingled wood,
every meadow, every field, displays to us. Hence in the
grove we see the woodruff and the herb Paris, later in the
summer the willow-herb and the fox-glove, on the rock
the oak-fern, the dragon’s-mouth, and the stone-crop,
side by side ; they take up the same nourishment, and
form their structures out of the same elements. What
maintains them in the distinctness ? It is the same force
that enables different animals to elaborate the same food
for such constantly varying bodily development, and, on
the other hand, prevents a considerable change of food
from effacing the specific type. This intern ally given
force of life is pre-eminently expressed in youth, while in
later age the formative forces are more and morefettered
to the products of their own activity, and work only in
a narrower circle, tili at length their activity, every -
where more hampered in its own products, becomes
extinguished.

For the definition of Rejuvenescence , we draw from
the foregoing considerations, the conclusion, that the
renouncement of forms already attained, and the retro-
gression to new rudiments, with which Rejuvenescence
begins, only mark the external side of the process, while
its inner and essential side is rather an inward yatheriny-

16

THE PHENOMENON OF

up, as it were a new draught from tlie proper source of
hfe, a renewed recollection of the specific purpose, or a
renovation of the conception of the typical ideal, which is
to be represented in the outward organism. This gives
to Rejuvenescence its definite relation to development,
which can only bring into gradually perfected repre-
sentation, that which lies in the essence of the creature,
that which is inwardly its own.

This inner part of the process of Rejuvenescence may
be rendered more clearly comprehensible by sleep, for
this also is a phenomenon of periodical Rejuvenescence,
the Rejuvenescence of the consciousness. In sleep the
mind is relaxed from the tension in which it is held
towards the outward world while awake. All images
and shapes of thinking life vanish, or appear only as
reflected pictures in drearns; the mind sinks back into a
condition comparable to that in which it was before it
first awoke to consciousness, therefore, externally regarded,
to a lower condition of development, for sleep is older
than waking in the history of development of human life.
But the mind does not lose itself in sleep, it rather
gathcrs itself up into new force, new comprehension of
its purpose, and much that crossed the waking thoughts,
scattered and entangled, becomes sifted and arranged
through this recollection.

Sleep, a necessary recreation for the mind, is equally
required by all the powers of the body immediately
serving the mind. The inner formative processes, on the
contrary, through which the body itself is preserved, do
not rest during this time of retreat, they rather act the
more undisturbedly and concentratedly. Hence the
rejuvenising power of sleep also for the body, which
appears so wonderful to us in many cases, as when sleep
occurs at the crisis in severe diseases. But the most
remarkable instance of the connexion of sleep with bodily
Rejuvenescence, is seen in the pupa-sleep of insects. Here,
where occur the most important metamorphoses we know
in the Animal kingdom, that of the sluggish Caterpillar

REJUVENESCENCE IN NATURE.

17

into the light-winged butterfly, the footless or headless
maggot into the deeply-segmented fly ; — here, also,
occurs the greatest retreat and gathering in of life, a
deeper sleep of weeks, months, or even years’ duration,
which may be compared with the embryonal sleep in the
earliest. period of formation of the organism, the sleep in
the egg. Without nourishment and without locomotion,
as it were shrouded in its pupa- coats, the insect prepares
the rejuvenised body for its future resurrection into a
freer, more mobile existence.

The awakening of the butterfly from the pupa-sleep,
recalls to us the awakening of Nature from its winter sleep
in Spring ; and this leads us to the proper subject of the
present considerations, — the Rejuvenescence in Vegetable
life. The Vegetable Kingdom is, indeed, the principal
workshop of Spring : “ the wonderful workshop where
myriads of vegetable atoms, in brief space, spin the
threads to clothe the trees and weave the verdant carpet
of the earth. With all its sunshine over land and sea,
with all its swelling streams and brooks, Spring would be
barren and empty without leaves and flowers, as a sky
without stars. Leaf and blossom alone give life and fresh-
ness to the active scene.” *

First of all, liowever, we must here dispel the illusion
that all the splendour of the new-born vegetable world,
which appears so magically in spring, is merely the work
of the few days in which it comes so suddenly into view.
No, the labour of Rejuvenescence begins earlier in thework-
shops of vegetable life, and Spring merely brings the last
steps before our eyes. The breath of Spring only urges
to its unfolding that which was preparecl long before in
silence, that which was reserving and strengthening itself
during the evil season of winter. For in the sarne pro-
portion as the vegetable world advanccs in summer and
autumn, — in shoot, leaf and flower, in wood and fruit, in
obedicnce to the impulse to outward representation, to

* Elias Fries, “ der Frühling” (Spring).
PP- 182, 214.

‘Archiv Scandinav. Beitrag,5 i,

2

18

THE PIIENOMENON OE

expansion ancl firmer establishment, does it retreat siniul-
taneously into itself in the formation of buds and seed, to
prepare the germs of new life. Thus the greater part of
that whicli unfolds itself in Spring, after winter has passed
over it, was already formed in the preceding summer and
autumn. Even now in August we find in the terminal
and lateral buds of the ocd within numerous, five-ranked
bud-scales, the rudiments of the leaves destined for
next year; nay, in the mostly paired terminal buds of
the lilac {Sy rin ga), we find not only these, but the rieh
thyrse of blossom for the future year, witli hundreds of
closely crowded flowers, wliich at this timeindeed appear
only as inconspicuous green nodules, scarcely the twelfth
part of a line in diameter. In the heart of the tulip
bulb, shielded by three- to four-fold succulent leaf-scales
(cataphyllous coats, Nieder blatt-hülle), exists, in autumn,
a little grecnish-yellow bud ; this is the tulip stem for the
next year, witli all the parts wliich it elevates from the
eartli nine montlis later, naraely, two or three leaves,
between whicli lies liidden the blossom, scarcely a third
of a line high, the petals and stamens appearing as ex-
tremely small, uniform papillse, scarcely distinguishable,
and not yet closed in as in later sliape of the llower-bud,
while the pistil is visible in the middle as a little, three-
lobcd papilla. The spike of the liyacynth is somewliat
more advanced, at the same period, in the interior of the
many-scalcd bulb, for the three outer petals of eacli flower
already begin to close up. In Ophioylossum, a stränge
little plant of the alliance of the Eerns, whicli unfolds
annually only one leaf and one spike, we find in May, in the
bud still liidden under ground, enclosed in a cellular cover-
ing, (not formed of cataphyllary leaves or bud-scales, but
thallus-like,) not only the leaf and spike for the next
year, but also the rudiment of the leaf for the year after that.

A further penetration into liidden workshops of Reju-
venescence in plants, requires, first of all, a more minute
investigation of the bud. The plant is bud, so long as
its existing rudiments are kept, in relation to completion,

REJUVENESCENCE IN NATURE.

19

in a stage of close connection of the organs. Those things
which are subsequently removed and unfolded, are here
still closely approximated, and, as it were, fitted one
within another. The bud is, therefore, properly regarded
as an entire young plant, and each new bud on an old
stem as a new plant, as an individual : “Gemma totidem
herba ” was an axiom laid down even by Linnseus, and
since bis day bas oftentiines been repeated.* Neverthe-
less, tbis conception of tbe bud bas remained itself to a
certain extent in tbe condition of a bud, since the sur-
prising abundance of conclusions clerivable from it, bave
never been properly developed up to tbe present time.
In tbe first place, however, tbe iclea of tbe bud as indi-
vidual still requires an essential Clearing up. Since tbe
word bud merely expresses a certain stage of existence of
the tbing in question, we mustbere ratber call this sprout
(Spross), in tbe definite sense tbat we bere understand
by sprout all belonging to one axis of tbe plant, tbat we
therefore regard as belonging to a sprout all which is
produced directly from one centre of Vegetation ( punctum
vegetationis ), and belongs essentially to one line of deve-
lopment. Eye and bud are only the commencement and
young condition of tbe sprout ; and that which we call
bud frequently comprehends only one part, and not the
whole of the sprout, as when tbe lower portion of a sprout
is already unfolded and the upper part of it alone remains
in the condition of a bud. Thus every ricbly clotbed,
but gradually progressing and gradually unfolding leaf-
bearing axis, as, for example, tbe sucker of tbe willow,
the rosette of tbe lettuce before its flower-stalk has arisen,
the crown of the palm or of tbe agave, has a bud (a
“heart”) hidden among the uppermost leaves, which
bud, however, passes by almost iraperceptible gradations
into the unfolded part of the crown, rosette, or slioot.
ln otber cases there is a sharper division between the
earlier unfolded parts and those remaining long in the

* For instance, by Röper, (‘Linusen,’ 1826, p. 434,) and quife reeentlv by
J. N. Carus, (‘Zur näheren Kenntnis s des Generationswechsels ,’ 30.)

20

THE PHENOMENON OE

bud state, in reference to tke period of unfolding and tlie
stage of formation ; thus, for instance, in the oak, the beech,
and other trees, where the leafy shoot terminates in a bud,
the shoot does indeed begin again with cataphyllary leaves
(bud-scales), and unfolds itself a year later than the pre-
ceding portion of the branch, bnt is, nevertheless, the
direct continuation of the axis, and therefore belono-s to
the same sprout. So also when a flovver-bud forms the
termination of a sprout, on which the preceding forma-
tions were unfolded earlicr than the terminal flower, as in
the tulip, the ranunculus and the pseony. Iience it is not
the separated bud which we must regard as an individual,
but the entire shoot, which in these cases includes several
superimposed buddings. A Rejuvenescence in the
course of formation of the plant, is indeed expressed in
each production of a bud ; but we must not, therefore,
attribute anequal individual importancc to each, for some
buddings belong to the individual completion of the par-
ticular branch (all terminal buds), wliile others form the
commencement of the new individual line of development
of a new sprout, as is the case in all lateral buds. If
individual value be attributed to the terminal buds also,
it will follow, in reference to the cases where the terminal
bud unfolds gradually, and is renewed in like progression
in the centre, that we must accord the rank of an indi-
vidual at last to every single leaf with its supporting
internode, since each is a specially rejuvenised link of the
progressive development. And if we attribute an equal
importance in this respect to each step of Rejuvenescence,
we cannot stop liere, for then every organ of the plant,
as internode and leaf, is itself again formed by a series of
Rejuvenescences, as we see in the cell-formation of the
organs; and the single cell itself finally has its own
periods of Rejuvenescence. Consequently, if we wisli to
review the various gradations of the phenomena of Reju-
venescence in vegetable life, we must consider separately :
— 1, the Formation of Sprouts ; 2, the Formation of
Leaves ; and, 3, the Formation of Cells.

REJUVENESCENCE IN NATURE.

2]

L— THE FORMATION OE SPROUTS.

There cannot be any cloubt that tlie formation of
sprouts belongs to the dass of tbe phenomena of Reju-
venescence, for with every sprout commences a new
train of development, the relation of which to the entire
developmental chain of the specific vegetable life, we have
here especially to investigate. The principal spront of
the plant takes its origin from the seed, and is indeed
merely the direct development of the seedling (embryo),
thus grown np from the first point of Vegetation of the
plant, which, traced backwards, leads to the primary
germinal vesicle. The lateral sprouts (branches), al-
though their origin is unconnected with the co-operation
of the sexes, agree with the main sprout in that they
also are developed from special centres of formation,
distinct, after their first origin, from the principal sprout.
We sliall return in the sequel to the origin of the principal
sprout, with which every new vegetable “stock”* arises,
when examining propagation from the point of view of
cell-formation ; here we must occupy ourselves with the
lateral sprouts, which belong to the sphere of com-
pletion ( Ausbildung ) of the vegetable “ stock” itself.

Unfortunately we are deficient in thoroughly worked-
out researches on the origin of the lateral sprouts or
branches ; but so much is known, that the origin of the
sprouts is subsequent to that of the leaves, that they
derive their origin from the already more developed
tissues of the stem, while the first rudiment of the leaf
coincides with the earliest stage of formation of tissue
underneath the point of Vegetation. f While the leaf,

* The word “ stock” is used here and elsewherc in the sense of what inay
be called a phytidom (like a polypidom), indicating the total organically
connected structnre composed of a nuinber of partially independent links
or inembers. — Trans.

t Vide Nägeli, ‘Zeitschrift für Wissenschaftl. Botanik,’ Heft iii, iv,
PP- 153, 177.

22

THE PHENOMENON OE

as essential part of the sprout, has its liistory of develop-
ment intimately connected vvitb that of the stem ;* on
the other liand the formation of the sprout does not
seem to have any essential connection with the com-
pletion of the stem from which it proceeds. This is
further confirmed by the circumstance that the sprouts
are not always distributed, like the leaves, in definitely
regulated Order on the stem, but in many cases may
arise without Order at any points of herbaceous stems,f
or of the older lignified trunk, nay even from the rootj
and the leaf, as the so-called adventitious buds.

It is a remarkable indication for the essential dis-
tinction in the origin of the leaf and sprout, that no
adventitious leaves occur. The character of the new
formation is expressed most distinctly in the formation of
adventitious buds making its appearance in detached
fragmen ts ofroots of woody plants, as has been described
by Trecul in Ailantlius , Pcndownia , Tecoma , and Maclura.
Here, in a decp-seated layer of the cellular bark, a new
locus of development is formed through a local thicken-
ing of the cellular tissue, and on this point again origi-
nates a mucli more delicate mass of cellular tissue, a new
sphcre of formation, which soon grows externally, al-
though still enclosed in the tissue of the bark, into a
leaf-producing point of Vegetation, and on the inside
strikes, stem-likc, into the formative zone (the cam-
bium -layer) of the root, there, by the formation of a
proper System of vessels, which takes its origin on the
limit between the stem of the adventitious bud and the
wood-cylinder of the root, acquiring a firm connection

* The essential interconnection of the leaf and stem is expressed in the
completed structure also, in the lact that there is no sharply defined limit
between the leaf and the portion of stem bearing it. Remark, for instance,
the pulvini graduallv lost in the stem of Larix, Picea, Cactem, Cacalia
articulata, &c., and stems winged by the decurrence of the borders of leaves.

f In Euphorbia, Linaria, and Änagallis, from the internode below the
cotyledons.

| Frequently in woody, rarely in herbaceous plants, e. rj. Euporbia Cypar-
isaias, Linaria , Rumex acetosella , Ajuya genevetisis, Nasturtium pyrenaicum,
Jurinea Pollichii, and Ilelichrysum arenarium.

REJUVENESCENCE IN NATURE.

23

with the latter.* The bucl breaks out subsequently
through the bark in which it was previously concealed.
In tliis instance there can be no doubt that the sprout is
really a new, and in tliis case even an accidental product,
a new commencement of life, which creates its own
sphere of formation, its own point of Vegetation, and
through the development of tliis, its own axis, around
which it arranges its Organs. Hereby we are warranted
in regarding the sprout as an individual , for, if we may
ascribe individuality to the plant generally, in which we
are certainly justified by the repetition of its mode of
appearance in determinate cycles of development, we
raust, consequently, conceive the individual as a clevelop-
raental series of unit power, and set up as its criterion
the unity of the point of Vegetation from which the series
proceeds, or, in the developed condition, the unity of the
axis. According to tliis, only the simple sprout can be
regarded as a vegetable individual, and that tliis, far
as the vegetable individual Stands behind the animal
individual in inner unity, is actually the analogue of the
animal individual, is proved beyond all doubt by com-
parison with tliose animals in which “ family Stocks” are
produced by the formation of sprouts.

The formation of the compound vegetable “Stocks”
(trunks or common stems) is thus a phenomenon of pro-
pagation, if we use this expression according to the
meaning of the word and the custom of language, in
general application to the production of new individuals
for the increase and maintenance of the species of plant.
Propagation by the formation of sprouts, 011 which not
only depends the formation of compound Stocks, but in
which is also given the possibility of the formation of
separate Stocks, has indeed been distinguished as liiere
multiplication from the proper (sexual) propagation, or

* Trecul ‘ Recherches sur l’Origine des Bourgeons Adventifs.’ ‘ Ann.
des Sc. Nat.,’ 3 s6r. viii, 268, 1847. The cases there described as two
different modes of origin, and represented in Plate vii, fig. 6 under b and //,
may probably be only stages of onc and the same process.

24

THE PHENOMENON OF

callcd propagation of the individual, in contradistinctioii
to the propagation of the species effected by the forma-
tion of seeds.* But, disregarding the contradictions
which here exist even in the expression, these definitions
by no means reach the true essence of the modes of
propagation occurring in the formation of sprouts, for it
is incorrect that the formation of the sprout is mere'ly for
the object of multiplication, as I sliall endeavonr to show
in the seqnel ; in like manner it does not always apply,
that the new Stocks formed by Separation of sprouts
(cuttings, laycrs, &c.) constantly retain nnaltered the indi-
vidual (rnore accurately the varietys) character of the
parent stock, for even without Separation from the stock,
particular shoots “ sport,” as it is callcd, out of the species.
The well-known exaniple of the occurrence of isolated blue
bunches of grapes on Stocks of white varieties, isolated
bunches of red currants mingled with the white ones of
tlie same stock, isolated pure sulphnr-yellow roses among
variegated flowers of the red and yellow Austrian briar-
rose ( Rosa cglanteria, var. licolor ) afford proofs of this.
The remarkable phcnomena relating to this point in the
hybrid Cytisus Adami, which displays in particular
sprouts the characters sometimes of one, sometimes of
the other parent species, will have more particular atten-
tion paid to them in another place.

The true import of the formation of sprouts upon the
vegetable stock is that of a subordinate propagation.
The cycle of development given by the sexual propaga-
tion (formation of seed) divides again, in the majority of
plants, in the most varied manner, into subordinate
series of development, which proceed out of one another
by the formation of sprouts, so that what in more highly
individualised beings is completed in the simple indi-
vidual, is distributed in the plant, through the inter-

* Link, ‘Element. Philos. Bot.,’ p. 208. “Gcmmse Individuum con-
tinuant, cum semina speciem propagent.” We have already shown above
that the lateral sprout, morphologically considered, is no continuation, but a
new beginning.

RKJUVENESCENCE IN NATURE.

25

position of a subordinate process of propagation, among
a society of individuals, a developraental series, and a
family circle formed thereby. The subordinate nature
of tliis mode of propagation represented by the formation
of sprouts is expressed — 1. In the connection of the
formation of sprouts witli the lower stages of develop-
ment of the plant. 2. In the imperfection of the
“ sprout individual” in reference to the series of stages
of development which specifically belong to the plant.
3. In the complementary relations in which the various
sprouts of the same plant stand towards each other.

In the first respect, all sprouts agree, witli the ex-
ception of the seed-sprouts (commonly called ovules),
which as standing in the closest relation to sexual propa-
gation, may be here left out of consideration. All other
sprouts spring from theso-called vegetative region, while
inside the flower, omitting monstrous occurrences in
antholyses, no more formation of sprouts takes place.
The catapliyllary ( Nieder-blatt ) region, the euphyllary
( Laub ) region, and the hypsophyllary (. Hoch-Matt ) region,
have more abundant ormore sparing formation of sprouts
according to the peculiarity of the species of plant ; nay
the production of sprouts is not unknown, as already
mentioned, in the descencling portion of the plant, the
root. How characteristic the formation of sprouts is of
the vegetable “stock” is sliown by the circumstance that
tliere exists perhaps not one single plant wholly without
the formation of sprouts.* If this assertion look at first
stränge, considering the number of plants which are
diagnosed witli “ caule simplici” and “ simplicissimo,”
more accurate examination of such plants as appear
to want the formation of sprouts, will readily confirm it.
A few instances may serve to bear this out. Cicendia
filrformis is certainly one of the simplest plants in this
respect. A delicate threadlike stem bears a few pairs
of small euphyllary leaves and ends in a terminal blossom.

* The leafless plants of the lowest ranks of the vegetable kingdom are
temporarily passed over in this assertion.

26

THE PHENOMENON OE

But the rudiments of the formation of sprouts exist in
the axils of the lower leaves of this series, and quite as
many speciraens may be fonnd with one or two branches,
as perfectly simple. In a similar way, in many other
plants which usually possess abundant ramification, we
find specimens which, under the influence of unfavorable
conditions, do not complete the branches which really
exist in rudiment, and therefore appear quite simple.
Such simple “ arrests” ( Kümmerlinge ) occur, for example,
in Erythrcea pulchella , Gentiana utriculosa, Saxifraga
tridactglites, Silene conica , Ggpsophila muralis , Papaver
Rfucas, Myosurus minimus , &c. In all these cases, there-
fore, the want of branches depends solely upon an acci-
dental obstruction. Otlier plants appear simple because
the formation of sprouts is hidden beneath, or is close
down upon the earth, as in the tulip, which forms sprouts
in the cataphyllary leaf region (bulbels), also Trollius
curopeeus, Papaver nudicaule, Gentiana verna , which
form sprouts in the axils of the ground leaves (“ radical”
leaves), whereby the originally simple “ stock ” passes
into a caespitose complexity, and acquires what is called a
“ radix multiceps.” Paris is deceptive in another way,
tlie simple and one-fiowered erect. stem being itself a
lateral sprout from a subterranean cataphyllary-leavcd
stem (rhizome). Among the simplest plants altogether
devoid of sprouts, apparently presenting solely a flower
without a stem, is the celebrated Baßesia and the para-
sites nearly allied to it. ; but it is most probable that the
flowers of these plants arise as sprouts out of a thallus-
like basis, creeping along under the bark of the nursing
plant.* The Melocactece form an exception in the family
to which they belong, ungrateful to the admirers of that
family, in sending out no sprouts from their green,
globular “ Stocks but here also the rudiments of the
formation of sprouts are indicated, by headed-down
“ Stocks,” sometimes sending out sprouts from the lower

* Scc R. Brown ‘ On 11 ic Fcmalc Flower and Fruit of Raßesia Arnoldi &c.
‘Trans. Linn. Soc.,’ xix, 3, p. 232 (nofe).

REJUVENESCENCE IN NATURE.

27

portion ; moreover, Melocactus normally exhibits formation
of sprouts in the terminal tuft of flovvers, in which (as in all
Cacteae) the flovvers stand laterally. The palms are also
mentioned as plants which usually form no sprouts ; but
leaving out Cucifera thebaica, which acquires a multiple
crown by the formation of leafy branches, the inflorescences
originating in the axils of the leaves are lateral sprouts.
Coryplia umbraculifera, with terminal inflorescence, has,
in the inflorescence itself, i. e. in the hypsophyllary leaf re-
gion, an extremely rieh ramification, carried out to many
degrees, and in addition to this, sends out sprouts from the
root, at the time of the maturation of the fruit.* Cyccis
would have better right than the palms to be regarded as
a plant devoid of sprouts, at all events if the cone-
or Ananas-like male blossom is terminal, as Richard
expressly States. But Rumph says of Cyccis circinalis,
that the stem at first grows very slowly, but afterwards
more rapidly, particularly when it has borne the “ananas.”
Such a continuation of the growth of the stem can, how-
ever, only be conceived through the formation of a lateral
sprout, if the male blossom is actually terminal, or, if a
direct Prolongation of the stem occurs, the male blossom
must loe a lateral sprout. The female tree of Cycas
circinalis is stated by Rheede f to divide frequently into
four or five tops when old, which again can only take
place by the formation of sprouts. Lastly, in Cycas
revoluta, formation of sprouts from the lower part of
oldish stems. mostly close down to the grouncl, is quite a
common phenomenon, and may be seen in every old
trunk in our gardens ; recurring moreover in the fossil
stems of Cycadem.j Many Ferns, especially most tree-
ferns, would appear as sproutless plants, in the strictest
sense of the word, were not the entire Fern stem itself a

* Vide Mohl, in Martius’s ‘ History of the Palms.’ The palms are also
very subject to subterraneous branehing, and lateral sprouts sometimes break
out from old leaf-axils on full-grown trunks. — A. H.
t Hist. Malabar., iii, t. 20, (lg. 3.

X See platcs in Buckland’s ‘ Geology and Mincralogv,’ t. 58, 60, 6],

28

THE PHENOMENON OF

second generation, i.e. a sprout produced from the
thallus-like pro-embryo Q vrothattium). The circumstances
are similar in Isoetes. Tims, even after very extensive
investigation, there probably does not remain to us one
single plant which, through the whole course of its deve-
lopment, from the germinal vesicle to the fruit, is bat a
single, simple individual, uncomplicated by subordinate
propagation.*

The subordinate condition of the propagation pre-
senting itself underthe form of the production of sprouts
is expressed, secondly, in the fact that the particular
sprouts, and indeed the main sprout as well as the lateral
sprouts, do not, in the majority of cases, bring into exist-
ence all the stages of vegetable metamorphosis which
belong to the <( stock ” as a whole. Consequently there
exist, in reference to the share in the graduated structure
of the entire plant, sprouts of different ldnds, and the
individual sprout on that account mostly represents only
morc or less imperfcctly the history of life of the plant.

The deficicncy of the sprout may relate either to its
eommencement or its conclusion. The formation with
which a sprout commences mostly Stands in relation to
the region of the parent-shoot from which it takes origin.
ri’hus we frequently sce a series of sprouts, accurately
graduated in this respect, arise from successive regions of
the (absolute or relative) main-sprouts, e.g. sprouts
beginning with cataphyllary structures from the cataphyl-
lary region, with eupliyllary leaves from the euphyllary
region, with hypsophyllary structures from the hypsophyl-
lary region. Hypericum perforatiim and Mentha aquatica
are well-known examples exhibiting this phenomenon.
Hut a retrogression of the sprout to a lower formation, as
well as an advance to a higher, is possible. The former

* See ou this subject, Hofmeister, ‘ Erucht-bilding, &c. der höher. Krypto-
gamen,” Leipsic, 1851. He however regards the ironds o! ferns as brauches,
a view which does uot appear admissible. The first product from the pro-
thallum is the primary axis of a new individual, continued hy a terminal
growtli, but forking of the rhizomc may occur, and this must depeud on the
formation of secondary sprouts. In Tsoelos the stem appears simple. — A. H.

REJUVENESCENCE IN NATURE.

29

occurs especially when the sprout is destined to be sub-
sequently developed into the central slioot. Tlius many
lilies exhibit in the axils of the euphyllary leaves cata-
phyllary bnds, which finally fall off as bulbels, and con-
tinue their development in the following year ; so also
we see the bnds formed in the axils of the euphyllary
leaves of most. trees, intended to overlast the winter and
unfold in the next year, conunence witli cataphyllary
structures. In many instances the plant first reaclies the
lowest stage of its metamorphoses by such a retrogression,
the lateral sprout going down to a lower rudiment than
the main or original sprout brought forth by the seed.
This is a process through which the plant enters more
closely into connexion with the earth in the second
generation than in the first, and becomes more firmly
established in it, preparing a more fixed, enduring and
sheltered existence, to the vegetable life, thougli its cata-
phyllary formation and the adventitious roots mostly fol-
lowing this. The following remarks may serve to illus-
trate this case, which is especially important in reference
to the biology of perennial herbaceous plants. It is self-
evident that the cotyledons of Dicotyledonous plants,
although mostly strikingly different * in shape from all
the following leaves, do not belong to the lowest leaf-
formation, but rather bear, essentially, the characters of
the second leaf-formation, that of the euphyllary leaves ;
while, on the other hand, the sheath-like cotyledon of the
Monocotyledons is mostly decidedly like a cataphyllary
leaf. Now Dicotyledons continue the euphyllary forma-
tion directly from the cotyledons, without ever producing
cataphyllary leaves either on the main or the lateral
sprouts ; perennial Dicotyledons, on the other hand,
mostly descend from the original leafiness to cataphyllary
formation, and this either on the main sprout itself, as in
Adoxa, Ilelleborm niger, Hejjatica , and Anemone nemo-

* The first leaves of the sprouts have been compared with the cotyledons
of the main sprout, a ground for which is indeed to be found in their position,
but only rarefy in their forms.

30

THE PHENOMENON OE

rosa ; or on the lateral sprouts arising from the axils of
the cotyledons and the euphyllary leaves next succeeding
these on the main sprout, in which case the main sprout
dies down either entirely, or at least in the upper part,
and this indeed mostly without having carried its develop-
ment up to blossoming; while the lateral sprouts last
throughthe winter in the formof basilar buds or runners
penetrating into the soil, and in the second year bring
forth a more vigorous generation, mostly advancing to
the terminal point, blossom and fruit. This is the condi-
tion, for instance, of most of the perennial species of Aster,
Solidago , Achillea, Tanacetum , Mentha, Lysimachia, Hy-
pericum, Epilobium, Lythrum, &c. ; Oxalis stricia and
Solanum tuberosum also belong here, in which the parent
stem dies entirely away, and onlythe ends of the runners live
over the winter as the foundations of a new, more vigor-
ous generation. It is well known that the potato raised
from seed does not usually flower, or only exceptionally.
Perhaps, however, Physalis Alkekengi affords one of the
best examples of this ldnd. Between the stalked, broadly
lanceolate cotyledons of this plant, spreading out above
ground, rises in germination a stein about a span high,
witli twelve or thirteen (euphyllary) leaves, increasing in
size upwards, and whcn winter approaches this stem dies
down without having flowered. ln the axils of the
cotyledons and the succeeding leaves standing close
down to the earth, in the course of the summer, while
the sterile main sprout is being developed further up-
wards, arise buds, which, scarcely a line long, turn their
points at once oblicpiely downwards, and subsequently,
becoming more and more elongated, penetrate almost
perpendicularly into the earth. They are clothed witli
distant, clasping, apiculated, cataphyllary leaves, bent
inwards like a cap at the tips, and these are reddish
above ground, whitish beneath. The uppermost of these
sprouts penetrating into the earth and laying the founda-
tion of the more vigorous and fertile generation ol the
second year, begin again witli small, dwarfed, euphyllary

KEJUVENESCENCE IN NATURE.

31

leaflets, and descend gradually on the tips penetrating
into the earth to cataphyllary leaf-formation.

The anticipatory condition of the sprout is no less
frequent than the retrogressive. It occurs, for example,
where we see flowers arise without bracts ( Vorblätter ), or
with such leaves as belong to the hypsophyllary leaf-
formation, from the axils of euphyllary leaves, as in
Linaria cymbalaria , Lysimachia Nuvnmularia , Tropao-
lum, &c.

More important for our purpose is the consideration of
the deficiencies of the sprouts in the upper part , i. e. in
reference to the formation with which they close. Not
every sprout carries the developmental series, whether it
take it up lower down or higher up, to its termination in
the formation of flower and fruit ; but certain determinate
sprouts remain fixed at determinate subordinate stages,
beyond which they liave no power, or only in extraordinary
cases, to advance ; nay, there are even cases where instead
of an advance to the final term in the building onwards
of the sprout, a retrogression of the metamorpliosis takes
place, which is frequently followed by a periodical Vibra-
tion up and down of the formations, connected with the
changes of the seasons. So, for instance, in the oak, the
beech, and the chesnut, the sprouts of which produce
cataphyllary and euphyllary leaves in regulär alternation
from year to year.*

These limitations downwards and upwarcls, which de-
termine the history of the individual sprout, in contra-
distinction to the history of the life of the entire plant,
form the most essential causes of the infinite multiplicity
we rneet with in the formation of sprouts in vegetables.
Tar removed, therefore, from merely subserving to an
asexual increase and a multiplication of identities, the
plant rather developes its great multiplicity in tliis very
formation of sprouts, and thereby becomes a “ veyetcible”

* The same is the case with Adoxa, which creeps aloug the ground and
rises and dcscends in undulations with the alternation of euphyllary and
cataphyllary formations.

32

THE PHENOMENON OF

{Gewächs), i. e. a whole composed of subordinate indi-
viduals.

Lastly, the subordinate import of tlie sprout is ex-
pressed, thirdly, most distinctly in tlieir reciprocal com-
pensations. For how were it otherwise possible in the
frequently so one-sided endowment of the sprout, limited
to a few, nay often to a single formation ? A mere cata-
phyllary sprout necessarily requires tlie appearance of
euphyllary formation in another series of sprouts, and
when tliese again do not procecd as far as the formation
of hypsophyllary leaves and flowers, further ranks of
sprouts must be introduced. Tlius in the pine we find on
the main-shoot and the branches resembling it (in the
earliest youth of the germinating seedling excepted), only
scale-like cataphyllary leaves ; tlie euphyllary formation
so requisite to the tree is committed to a second order of
sprouts, to the little branchlets which bear the two, three*
or five-fold bunches of aciculate euphyllary leaves. These,
however, produce neither flower nor fruit ; it is a new
rank of sprouts which produces the staminal leaves
(stamens), and again, another which forms the foundation
of the cone, on which, as the last formation of sprouts
appear the fruit-scales, in the axils of the bracteal scales
(hypsophyllary leaves) of the cone. Thus the pine has
five qualitatively different Orders of sprouts, or, if we
count as a separate rank the main-sprout or trunk, dif-
fering in its earlier behaviour from the branches which
form the crown of the tree, even six.

The most important and interesting point revealed by
tliese investigations, is the definite order of generation in
which the different ranks of sprouts proceed one out of
another. Only a small proportion, namely, of (Phanero-
gamic) plants, reach the goal of the metainorphosis,
blossom and fruit, in the first generation ; the majority
attain this term only in the second, tliird, fourth, or some-
times not until the fifth generation of sprouts* Every

* If we include the seed-bud (ovule) as the last generation of sprouts, we
liave, for all plants which do not possess a “ terminal” or “ central” ovule, a

RKJ UVENESOENCE IN NATURE.

33

vegetable species lias its specific law in this, and soine-
tinies even nearly related species are distinguished by
tlieir character in this respect;* raore frequently, how-
ever, the species of a genus, nay even the genera of a
family, follow essentially the same order in the production
of sprouts. Thus, for instance, the Grasses, Cyperaceae,
Orchideae, Labiatae, Scrophnlarineae, Primulaceae, Cruci-
ferae, Onagreae, Malvaceae, Dipsaceae, and Compositae,
never attain the flower in the first, mostly in the second,
but sometimes not until the third generation ; the Plan-
tagineae, as well as the majority of the Scitamineae,
Amentaeeae, and Legnrainosae, mostly in the third ; a
few of the last, as Phaseolus , Apios, Hedysarum coronci-
rium , and Trifolium montanum in the fourth. But this
enumeration of the essential generations of sprouts, or,
as they may be called, the System of axes of the plant,
merely marks the most general outlines of conditions
which include an infinite multiplicity of subordinate cases.
The number of the axes being equal, they divide, in the
first place, according to the distribution of the formations
on the axes in question. Especially important in this respect
is the behaviour of the last axis, which bears the flower.
Whether the last axis sets the flower immediately, f or
after the preceding formation of a definite number of
leaves,! or, finally, an indefinite number of leaves precede
the flower, § are distinctions of importance even as
characters of families. But also witli like distribution of
the formations, further distinctions occur in reference to
the region from which the next System of the axes arises ;
as also, lastly, less essential ones, of great importance
however in regard to the habit of the plant, in respect to

still further term in the series of generations, and the really uniaxial plants
are then rcduced almost to none,

* Note the genera Echium, Arabis, Sagina, Silene , Potentilla , Viola,
Lynmachiu , Veronica, &c. See the Eatisbon ‘Flora,’ 1842, 692.

t Cyperacere, Orchidea;, Crucifcrm, Balsamincae, Primulaceae.

+ Gramme® and Indem liavc one bract ( Vorblatt ) ; Labiat®, Scrophu-
lariue®, Lythrarie®, and Legumiuos®, liavc two ; Gesneriacece liave three.

§ Polemoniace®, Liguslrinece.

3

34

TUE PHENOMENON OF

the number of the co- Ordinate sprouts of each rank, the
region and the abundance in which the said fonnations
occnr on the varions axes, the relative diniensions of
these axes, &c. A few examples placed side bv side for
the sake of comparison, may render these further dis-
tinctions more clear.

Paris quadrifolia and Lysimachia Nummularia , both
liave a two-rnembered cliain of sprouts ; but the endow-
ment of the two axes is quite different. In Paris, i is a
cataphyllary sprout creeping Underground ; ii, brings forth
successivcly a basilar cataphyllary formation, the euphyl-
lary formation, and the flower. In Lysimachia Nummu-
laria, i is a creeping cnphyllary sprout; ii, imrnediately
produces the flower.

Convallaria majalis and Convallaria multijlora liave
both three-membered series of sprouts, both also liave the
sanie distribution of the fonnations, namely, on axis i,
the cataphyllary and euphyllary formation ; on ii, the
hypsophyllary formation ; wliilc iii concludes with the
flower. But tliey are distinguished in the relations of the
emergence of the shoots ; in Convallaria majalis, ii, arises
from the cataphyllary region of i ; in Convallaria multi-
jlora from the euphyllary region. Tliey difler, morcover, in
reference to the number of the co-ordinate sprouts, since
Convallaria majalis possesses only a single sprout of the
second generation, tlius only one inflorescence; Convallaria
multijlora numerous inflorescences, but less numerous
sprouts of the third generation, i. e. only a few flowers in
each inflorescence. Cyclamen and Centunculus both have
two-membered series of sprouts, both the same distribution
of the fonnations and the same regions of origin of the
sprouts : i, being a euphyllary sprout ; ii, blossoms from
the axils of the euphyllary leaves. Here the relative
dimensions are the principal causes of the very different
habit. In Cyclamen, i is a tuberous stock; ii, the
blossom, on the other liand, has an elongated stalk ; in
Centunculus , on the contrary, i is a delicate little sprout,
Avhile the flower is almost sessile.

REJUVENESCENCE IN NATURE.

35

Plantago major and Impaliens Balsamina owe their
very different habit, in like manner, principally to the
different relative dimensions. In both, i is a euphyllary
spront ; in both the ii, hypsophyllary leaf bearin g sprouts
(the axes of the inflorescences), arise from the axils of
the euphyllary leaves ; from the axils of the hypsophyllary
leaves (bracts), finally, iii, the flowers ; but i is a short
stock in Plantago, forming a rosette upon the ground.
In Impatiens it is a very much elongated sprout ; ii, on
the contrary, is a sprout in Plantago , especially elongated
in the lowest part, and thereby forming the shaft, or
rachis, as it is called. In Impatiens , on the contrary, it
is an extremely short stalk, thus hidden in the axil of
the leaf ; iii, the flower, is sessile in Plantago, and fur-
nished with a long stalk in Impatiens. In ii is to be
added the distinction in reference to the abunclance in
wliich the formation occurs, for in Plantago a great
number of hypsophyllary leaves exist, laying the founda-
tion of a rieh spike ; while in Impatiens there are but few
hypsophyllary leaves, which is the cause of the poverty of
blossom in the small axillary cyine.

The complementary relations of the sprouts become
still more manifold through the superacldition of a clivision
of a generation, to the consecutive series of generations,
which can start from any generation contained in the
vegetable “ stock,5’ but in many cases appears even in
the first generation, produced by sexual propagation, and
then gives rise to the existence of two different comple-
mentary “ Stocks.55 The latter is the case in all dicecious
plants, the former in the monoecious, unless the case
occurs of the terminal stmetures distributed to the two
kinds of flowers being attained by a simple series of
generations. Cases of moncecia through division of genß-
rat.ion, so that one part of the sprouts belonging to the
same generation terminates (immediately, or even in the
second or third line) with male flowers, another portion
with female flowers, occur in P aclgsandra, Anim , Sil-
plnum , Calendula, and Eriocaulon, in which the flowers

36

THE PH EN OMEN ON OE

belonging to the same spike or the same capitule, i. e.
arising from the same parent axis and tlius forming only
one generation, are partly male (the lower or outer) and
partly female. The Hornbeam ( Carpinus) may furnish
an example of a more complicated case. Male and female
catkins arise as co-ordinate sprouts from the same parent
axis, but the male flowers form thesecond generation on the
male catkins, the female blossoms the third generation on
the female inflorescences. The division of the generations
occurs therefore here in the last generation but one for
the males, in the last but two for the females ; the two
kinds of catkin are, to a certain extent, themselves agaiu
“stocks” upon the “stock,” the male “stock” (catkin)
with two-membered, the female with three-membered
serics of generations.* Examples of monoecioiis condition
through mcre succession of generations are furnished by
many Euphorbiacese, for instance, Euphorbia and Euxus,
where the male lilossoms are produced as lateral sprouts
from the sprouts terminating with female flowers. f
Besides the sprouts wliich present themselves as essen-
tial members of succession of generations and of division
of generations, and consequently are necessary to the full
carrying out of the series of formations up to blossom
and fruit, most plants possess other sprouts, wliich are
not necessarily connected licre, and therefore maybe dis-
tinguished from tliose hitherto examined, under thenaine
of inessential sprouts. In plants wliich possess terminal
flowers, i. e. in wliich the main-sprout terminates in a
fiower, all the lateral sprouts, however numerous and
regulär they may be, are to be regarded as inessential.
The inessential sprouts enrich the “ stock ” within the
annual period of Vegetation, if they succeed the main
sprout quickly in tlieir- development, as is the case, for
example, among annual plants (summer plants) with
all the sprouts; in herbaceous perennials with the

* Jt is similar in Qußi'cus, only lierc botli tlic female and the male flowers
form the second generation within tlieir inflorescences.

f Sarcocucca exhibits the reverse.

RE J U V EN ESCEN C K IN NATURE.

37

upper sprouts. If tlie sprouts remain undeveloped, as
buds, until tlie commencement of a new period of Vege-
tation, tliey maintain and renew tlie plant, while the old
“stock,” in so far as it bears such buds capable of
development, does not die away, as is seen in perennial
lierbs, half-shmbs, and true woody plants, in whicli less
or greater, merely Underground or also an above-ground
portion of the “stock” is preserved. This gives the pos-
sibility for the plant to rise up in new generations from
the same stock, year after year, and thus repeatedly to
produce flower and fruit. Finally, if such inessential
sprouts become detached, whether by dying away of the
old “stock,” as in the monk’s-hood {Aconitum Napelius) ,
the potato, and many bulbous plants ; or, the old “ stock”
persisting, by a natural solution of the connection with
it, as in the young plants springing from the runners of
the strawberry, — the sprout becomes anew “stock,” and
appears as a multiplying sprout , as a natural Iciyer. All
these modifications mayoccur in one and the same plant.
Thus the common spurge {Euphorbia Cypcirissias ), ex-
hibits two kinds of enrichment-sprouts above ground,
namely, in the euphyllary leaf region, the densely-leaved
spreading, mostly barren euphyllary sprouts, wliich give
the characteristic fulness to the euphyllary region of this
plant ; in the hysophyllary region, further, the branches
of the umbels arising from the circle of hypsophyllary
leaves beneath the small terminal capitules, with further
bifurcated and scorpioid ramifications of their branches,
forming the rieh and finely compound infloresence of this
plant. Below the ground, in the cataphyllary region,
occur in summer nurnerous small, reddish-white, little
buds ; these are the sustaininy and renovating sprouts of
the plant, arising with a cataphyllary forraation, advancecl
somewhat in development, and destined to shoot up in
the next year and renew the “stock.” Other little
sprouts, finally, not unlikc these, are inet with here and
there on the branches of the root approachingthe surface
of the earth, where however tliey assume an independent

38

THE PHENOMENON OP

character, through forming roots of their own, and sooner
or later become detaclied from tlie parent “ stock/’ tlius
presenting themselves as increase-sprouts or layers.

All these modifications in whicli the inessential
sprouts occur, agree in the circnmstance that they re-
present, in greater or less extension, only repetitions of
that whicli the plant possesses in its essential sprouts.
They lie outside the straight line towards the flower and
fruit, being interposed laterally, at various heights, as ines-
sential lines of repetition. ln many cases the presence
or absence of such repetition-sprouts, appears, usually,
as souiething accidental and indifferent to the plant, as
for instance, when the tulip stem acquires a branch with
a lateral flower. In general, however, these repetition-
sprouts are ofraore importance, and are inore necessary to
the plant than miglit appear, so that they must be regarded
as in certain respects essential, tlius, namely, in reference
to the characterisation and also to the economy of plants.

That the repetition-sprouts are characteristic, is ex-
pressed generally by their influence on the “ liabit” of
plants, on the architectural design of the “ stock,” whether
as a wliole, or in its separate parts, as in the inflorescence
cspecially. Entering more into particulars we find
characteristic features in the arrangement and direction
of the branches, in the frcquently peculiar arrangements
of theleavesand rudimen tary traces ofsucli arrangements
on the branches, in the laws of curvature of the lines of ar-
rangement of the leaveson rudimentary branches, especially
in the laws of antidromy occurring on the branches placed
symmetrically opposite to eacli other, in the relations of the
subtending leaves to the branches, particularly the con-
ditions of fusion of the two, &c. A multiplicity of good
and important characters would be altogether lost if the
inessential branches were removed ; nay even the mere
presence or absence of certain modifications of them, as
of subterranean or above-ground bulbeis,* stolons,t

* Tlius in the gcnus Saxifraga ; in S. granulata, and S. bnlbifera.

f See the genera Car ex, Epilobium, Hieracium, Valeriana, Viola.

REJUVENESCENCE IN NATURE.

39

above or belovv the cartli, witli or without tuberous struc-
tures, spine- branches,* &c., are characteristic of particular
species of plants. Thus, in spite of the distinction betvveen
essential ancl inessential sprouts, we must acknowledge,
that from a higher point of view all sprouts appear es-
sential. As it is not merely in the last stages of the
metamorphoses that the life reveals its peculiarities,
since every one of the lower stages also turns outwards
a special side of the living esseuce, not only are those
sprouts wliich bear relation to the attainnient of the goal
of the metamorphosis to be called essential, but also,
everything eise in the collective circle of those structures
wliich are destined to represent the plant on all sides, and
cannotbe removed from that circle without essential interfe-
rence witli the characterisation of the plant. A fewexamples
may render more clear the importance of the inessential
or repetition-sprouts in the characterisation of the plant.

The peculiar forms of the crowns of trees, for instance
of the pyramidal poplar, of the cypress, depend upon the
proportion of the vigour and abundance of the repetition-
sprouts to the main sprout or trunk of the tree. The
relation of arrangement shows itself more distinctly in
many Conifers, wliere the repetition-sprouts over-leap
certain tracts wliich remain without branches, and form
tolerably regulär whorls. In Pinus the tracts between
the larger, whorled branches are occupied by the small
(essential) leafy branchlets. Essential and inessential
sprouts occur in extrem ely regulär alternation in Tro-
pcBolum minus, when every tliird flower-sprout is followed
by a euphyllary leaf sprout. When there is f- arrange-
ment of the leaves on the main-shoot, the euphyllary leaf
sprouts derive from this an arrangement according to
f- in the reverse direction. Here also may be mentioned
the peculiar cases wliere the leaves having a many-ranked
direction, the branches are nevertheless in distichous
arrangement, on account of only part of the leaves pro-

* See Prunus, Pyrits, Cratcrgus, Rhamnus.

40

THE PHENOMENON OP

ducing branclies in their axils, as in the Arbor Vitae
{Thuja), and several of the branched Mosses, for instance,
Hypnum abietinum , delicatulum, tamariscinum, &c. Hence
arise pinnate forms of ramification, which frequently stop
at a determinate degree of pinnation ; as in the three
species of TTypnum just named, the first is simply, the
second doubly, the third triply, pinnate. In the Ilorse-
tails we see a determinate degree of ramification kept to,
even in a verticillate arrangement of the branches.* If
we take the characteristic branches away from such a
plant, it would lose its peculiar “ habit.” Imagine, for
instance, a Tamarisk ( Tamarix) robbed of its numerous
ininutely-leaved cuphyllary leaf twigs, and the fine bushy,
thousand-leaved, pyramidal slirub becomes a simple,
meagcr, naked rod, on which the distant, minute leaves
are scarcely visible. Even characters applicable to generic
distinction rnay vanish through removal of inessential
branches. All the lateral spikelets of Lolium and Triticum
are inessential, insomuch that a terminal spikelet exists ;
bat vvitli their removal is wholly lost the distinction be-
tween the tvvo genera, founded on the different commence-
ment of the branches of tliese lateral spikelets. Thus also
would one of the most important distinctions between the
genera Festuca and Bromus become imperceptiblc through
the disappearance of the panicle-branches, namely, the
one-sided direction of the first secondary brauch, which
principally distinguishes Festuca from Bromus. But
inflorcscences above all show most distinctly what im-
portant and weighty characters of plants are expressed
by mere repetition-shoots. All inflorescences having a
terminal flower, evidently consist, with the exception of the
main axis of the inflorescence terminating in that flower,
of repetition-sprouts ; and yet what distinction, what mul-
tiformity of structure, exists in these inflorescences ! What
a distinction, for instance, between the simple raceme of
Menyanthes and Berberis, the umbel of the coriander,

* Equisetum arvense and E. si/loalicum.

REJUVENESCENCE IN NATURE.

41

the pyramidal panicle of tlie lilac ( Syringd ) or the phlox,
and, finally, the antlielce of Luzula and Ulmaria , rendered
so remarkable by the strong development of the lower
tiower branches. But the essential lateral parts of the
spiked or racemose inflorescence may be developed to
most characteristic forms of the inflorescence, by inessen-
tial sprout-formation from the bracts ( Vorblätter ), e.g. to
the forked form , by the eqnilibrium of a homodromons
and antidromous sprout, to the screwed form by the pre-
dominance of the homodromous, to the scorpioid form by
the prevalence of the antidromous sprout. All these
characteristic forms are produced by mere succession of
inessential generations, wliich proceed one out of the other
according to determinate laws, and are frequently inti-
mately chained together into apparently continuous axes
( sympodia ) .

Another side, on which the sprouts which have been
termed inessential in the foregoing, appear in a deep and
essential connection with the course of existence of the
plant, is tlieir relation to the economy of vegetable life.
Formation of sprouts, generally, especially however the
formation of inessential sprouts retrograding to the lowest
stages of the metamorphosis, gives the plant the rneans of
attaching itself to the most varied conditions, of persisting
through periods of continued cold and heat, damp or
drought, according as the climate may produce, and
guarding against death in all cases of frustrated seed-for-
mation. Under the varied circumstances which may frus-
trate the fertilisation, under the readily possible prevention
of the formation of seed after fertilisation has taken place,
it is of importance, since the proper individual of the
plant (the simple sprout) can only once tiower and ripen
seed, that the “stock” should have the capacity, by
another kind of propagation, namely, the formation of
sprouts, of repeating the blossoming and ripening, either
in the same period of Vegetation, — whereby, for example,
in every many-flowercd inflorescence, any temporary dis-
turbance loses its effect upon the whole through succes-

42

THE P11EN0MEN0N OE

sive opening of the flowers, which is especially important
in the case of annuals, — or in a succeeding period of
Vegetation. The latter condition is particularly important
for such plants, as, in consequence of the contrivance of
the organs of fertilisation, rarely bear fertile seed, as is
the case witli most of the Orchideue, — as also for such as
through their Situation are often prevented from flowering
for a long time, as is the case witli many water-plants,
vvhen the level of water remains long very high. Tims
Littorella lacustris, which never flowers under water,
maintains and increases itself by lateral runners, year
after year, at the bottom of the lakes of the Black Forest,
and only comes into flower when the water retreats, in
the driest years, which scarcely recur oftener than once
in teil. Similar conditions are exhibited by many nemoral
]>lants, as for instance, the woodrutf; when the shade of
the wood is too dense, or even when too free an opening
of the wood interferes with its flourishing above-ground, it
maintains itself many years without flowering by subter-
ranean runners, waiting from generation to generation
the return of a season favorable to its success. The well-
known phenomenon that annual plants ahnost entirely
disappear in the extreme north and in the Alps, likewise
deserves to be mentioned here, since it shows how, in
proportion as the ripening of seed is endangered by cold,
a formation of sprouts adapted to the persistence through
the cold season takes place. Lastly, the formation of
sprouts is of especial importance for hybrid plants, which
as a rille can only bc maintained and increased by
naturally or artificially detached sprouts. The frequent
experience that hybrids of annual orbiennial plants, e.g.
the hybrids of the genus Verbascum ,* acquire a duration of
many years through continued formation of sprouts from
the old “ stock,” is a speaking testimony of the inter-
position of sprout-fonnation in cases where propagation
by seed is difficult or impossible, since in tliis instance

* j Jiave observed t-1 1 is phcnonicnon ;ilso in tlio bybnd between (Euothcru
biennis and muricalct , not unfrcrpicnt in tlic distvict of Ereiburg.

REJUVENESCENCE IN NATURE.

43

the longer maintenance of the hybrid form is effected by
a sprout-formation, not merely inessential in the sense
above denoted, but also quite extraordinary, and alto-
gether absent in the parents of the hybrid.

To these indications respecting the connection of the
inessential sprouts with the economy of vegetable life, we
have to add also the consideration of certain cases, which
completely remove the sharpness of theformer distinction,
since, as cases of transition, they may be taken in two ways.
In contrast to the essential sprouts, which, as determinate
series of subordinate generations in which the metamor-
phosis of the plant is carried to its term, represent,
according to number, a firmly fixed System of axes, each
successive one bringing something new — we have called
the inessential sprouts, lying outside the series and inde-
finite in number, repetition-generations. But cases occur
of real repetition-generations, which do not lie outside
the line, but belong to the series of transition generations
necessary to the attainment of the goal. Here refer the
strengthening generations — already noticed above* — of
many perennial plants, which in the first year are still too
weakly to form flowers and fruit. The fortification to
the point of fruitfulness may occur either in the next
succeeding generation, otherwise essentially like the first,
or deviating only in a retrogression to cataphyllary leaf-
formation, and thus in the second year, if every gene-
ration is destined to a year’s duration, — or, more or less
numerous, and then mostly numerically in determinate,
in all essentials completely similar generations, may suc-
ceed one another, tili at length that age of the “ stock”
is attained in which it advances to the formation of
blossom. The latter condition occurs especially frequently
in trees, and indeed most distinctly in those which have
no terminal buds, and consequently, in the strictest sense,
unfold each new year a generation composed of un-
doubtedly new individuals (evident lateral buds). Tlirec

* See pp. 29, 130.

44

THE PHENOMENON OF

examples, very unlike, but agreeing in the conditions
liere referred to, the asparagus, the lime, and the vine,
may be examined a little more minutely, to illustrate
this point.

The common asparagus [Asp. oßcinalis) differs from
otlier perennial herbs formerly mcntioned which arrive at
blossom only through strengthening generations, in the
circumstance that it produces several strengthening
generations in one and the same year, three or four in
fact cven in the first year, while in the succeeding years
the number of generations sprouting out of one another,
in one sunnner, amounts to eight or ten. The single
shoots of asparagus are namely, really so many successive
generations, and not as it might appear co-ordinate mem-
bers of one and the same generation, since the horizontal
root-stock is not a continuous axis, but a sympodium
formed by the chaining together of the basilar portions
of the individual shoots. Each succeeding shoot arising
from the axil of the second, sub-basilar. cataphyllary lcaf
of the forcgoing, hidden in the ground, is related anti-
dromously to the foregoing, like the successive flowers
of ascorpioid inflorescence. From the first shoot, arising
from the seed, which is the weakest of all, and sends
out the second, already somevvhat stronger, from the
axil of the first leaf after the cotyledon, the shoots
produced in scorpioid succession out of each otlier, in the
above-described way, increase in strength tili about the
fourth or fifth year, wlicn the asparagus has attained its
perfect vigour, which remains pretty equal for about
fifteen years, and then again gradually decrease with age.
A subordinate reaction occurs during this, the last slioots
of each year decreasing somewhat in strength. The
shoots of the first, and often even of the second year, are in-
fertile, for the asparagus does not usually flower until the
third year. Since three or four shoots are produced in
the first year, and five or six in the second, the asparagus
requires a series of eight to ten generations to strengthen
it up to the point of bearing. All generations, both

KEJ U VEN ESCENCE IN NATURE.

45

the earlier infertile and the later fertile ones, are essentially
alike in all other respects. The tirst slioot bears, after
the cotyledon, a basilar, subterranean, amplexical sheath-
ing leaf, then in the upraised stem distant smaller and
narrower scale-like leaves, which might be taken for
hypsophyllary leaves if they were not preferably to be re-
garded as cataphyllary formations, since it is their axils
that the aciculate, leafless branchlets, arise, which here,
as in Ruscus , take the place of the euphyllary leaves. The
slioot thus exhibits two essential axes, the main axis witli
two gradations of the cataphyllary formation, and the
leafless lateral branchlets, which represent the euphyllary
formation, and are mostly enriched by others similar
(inessential), whence arises the tufted arrangement of
these last branchlets. These two essential axes are re-
peated in all the succeeding slioots, only progressively
more vigorously and richly through the increased number
of leaves on the main axis, and through the occurrence of
inessential lateral branches, which repeat the upper part
of the main axis, and, finally in the most vigorous shoots
produce again lateral twigs of the second, third, or even
of the fourth degree, whence arises the stately panicled
growth of the asparagus. The essential axes are not mul-
tiplied by this enriclnnent until the flower, which arises
on each side from the basis of the branches, appears as
the third essential sprout-formation of the asparagus.
The bearing shoot of the asparagus has thus three different
and essential Systems of axes or generations of sprouts,
but appears, itself, as a whole, only after a series of gene-
rations resembling itself, but barren, which are indeed
repetitions of the like, but nevertheless essential prepa-
ratory or transition links.

Like the root-stock of the asparagus, the stem of the
lirae is also a sympodium ; for the lime, from the first
annual shoot of the germinating tree onwards, never pro-
duces terminal buds, the stem being dcveloped forth from
year to yearfrom the uppermost lateral shoot. The lime,
when raised from secd, grows very slowly, and does not

46

THE PHENOMENON OE

flower until it has attained an age of full thirty years ; so
that the number of necessary strengthening generations
is considerable here. Wlien the bearing age is attained,
the flower appears in the blossoming generation as the
third axial System, since it arises out of the axil of the
winglike first leaf of the lateral buds.

The relations of the strengthening generations are
much more complicated in the vine. The genninating
vine produces first two small leaf-like cotyledons, and
tlien a weak, upright shoot, scarcely a span high, witli seven
to ten, seldom more, euphyllary leaves, which are arranged
spirally according to the f or -f order. It is pro-
bable that a weak tendril-formation occurs at the summits
of vigorous scedlings, and beyond tliis an apparently di-
rect continuation from the uppermost euphyllary leaf, as
we are cnabled to make out more clearly on the shoots of
the succceding year ; but the whole of tliis uppermost por-
tion acquires, in any case, but a very sliglit development,
and dies at the top as the winter comes on.* Tliis first
main-sprout of the seedling forms the basis of the so-called
head ( ceps , in French), from which arise the climbing
shoots ( Ueb-sc/tosse ), following in the second year; but
these are produced through a peculiar agency. In the
axils of the euphyllary leaves, namely, (nay even of the
cotyledons,) buds are formed, on which we find, first a
cataphyllary leaf, then a euphyllary leaf, and the trace of
a tendril, which latter Organs, as well as those following
further on, are mostly very stunted in their development,
or even wither up before fully unfolded, while a new bud
is formed in the axil of the cataphyllary leaf, which be-
comes more s wollen than the chief bud, and is protectcd
by its own two cataphyllary leaves (bud-scales). In tliis

* Unfortunately I have no seedlings of the vine at disposal at present.
On those formerly observed I noticcd no formation of tendrils, but have seen
tliis in the radical sprouts (suckers), which bchave just like the seedlings in
the arr angement ofthe leaves and otherrespects. The statements as to the
conditions of the lateral axes of the first and second year are also derived
from the latter. (The supposition mentioned above was not confirmed by
later observation. See author’s prefacc, Trans.)

REJUVENESCENCE IN NATURE.

47

way, if the cliief bud is not unfolded, tbere arises the
appearance of two buds placed side by side, one drying
up and the other fresh. The stuntedly developed chief-
buds are no other than the first “Geitzen of the vine,
which are repeated in a more distinct manner in the fol-
lowing years ; frora the lateral buds, on the contrary, are
developed in the next years the first “ Lotten ’ of the vine,
which at once grow out more vigorously and more slender
than the head-shoot of the seedling, and, as the preceding
statements indicate, arise from the base of the stunted
“ Geitzen,” and not directly from the middle-shoot, tlms
representing properly a secundane , a ramification of the
second degree. The “ Lotten ” differs from the head-
shoot in many respects; they have never spiral, but
always distichous arrangement of the euphyllary leaves ;
they bear numerous tendrils, or “ forks,” as they are
called ; and, what is most important here, a minute ex-
amination shows that they are never simple, but linked
sprouts, forming a sympodium. It is well-known that
the tendrils of the vine stand opposite to the euphyllary
leaves ; this is explained by the fact that the tendril, as
the temporary apex of a sprout, becomes turned towards
the side by the succeecling sprout, arising from the axil
of the uppermost euphyllary leaf, while the new sprout is
attached upon the euphyllary region, as an apparently
direct Prolongation. Another point especially worthy of
remark in this is, the regulär alternation in the character
of the sprouts linked together to form a “Lotte” occurring
after the first member of this series of sprouts. The first
sprout with which the “Lotte” commences is different
from all the succeeding, since it commences with a cata-
phyllary formation (with the two basilar bud-scales,
visible even in the first year), and after this produces
mostly more than two (3 — 5) euphyllary leaves, before
it terminates with the formation of the tendril. The
tendril, like all the succeeding tendrils, bears a hypso-
phyllary leaflct, from the axil of which arises a brauch,
which gives the tendril the well-known forked form. All

48

TH 15 PHENOMENON OF

the succeeding sprouts (members of the series of genera-
tions of the “ Lotte”) are added upon the foregoing with-
out repetition of the cataphyllary formation, and possess
alternately one and two enphyllary leaves before the transi-
tion to the formation of the tendrils. From this arises quite
a peculiar arran gement of the tendrils, which are arranged
distichously, but in sucli a manner that two snccessive
tendrils always fall on the saine side, since every third
leaf of the “ Lotte' ” is without an opposite tendril.* It
is further to be remarked, that the imposition of the dis-
tichous arrangement of the leaves occurs with prosenthesis
on the first or basal sprout of the “Lotte” while all the
following commence without prosenthesis ; hence arises
the nnintcrrupted continuation of the distichous arrange-
ment of the euphyllary leaves, throngh the whole ehain of
sprouts of the “Lotte” while at the origin of the “Lotte”
occurs a Crossing of the ranks with the subtending leaf
(the basilar cataphyllary leaf of the “ Geitz .” In the

axils of the euphyllary leaves of the “Lotte” new buds
are formed, unfolded more or less perfectly during the
coursc of the summer, and representing the branches of
the “Lotte,” which liave a Connection similar to the
“Ljotte” itself, i. e. are in like manner chains of sprouts.
They are weaker than the “ Ljotte” from which they
arise; very often only very poorly developed, especially
on the lower parts of the “Lotten.” These are the true
“Geitzen” of the vine, which we inet with in a yet almost
irrecognisable condition of development on the principal
shoot. They form the second annual series of generations,
and are distinguished from the “Lotten” by their basal
sprouts possessing constantly only one cataphyllary leaf
and two euphyllary leaves. Although all “Geitzen” are
of similar nature, they originate in two ways, part,
namely, are primary axillary sprouts (those from the axil
of the lower euphyllary leaf of the two-leaved joints of
the “Lotte”) ; part secondary (accessory) axillary sprouts

* I liave found this constant, not only in Vitis vinifera but also in several
American vines.

REJUVENESCENCE IN NATURE.

49

(thöse frora the axil of the upper leaf of the two-leaved
and of the single leaf of the one-leaved joints of the
“Lotte”). Therefore, on the two-leaved joints of the
“Lotte” the secondary sprout from the upper leaf-axil
behaves like the primary sprout from the lower, while it
is essentially different from the primary sprout of the
upper, since the primary sprout (which carries on the
Lotte”) is added on without a cataphyllary leaf and without
prosent/iesis, and the secondary sprout (which forms the
“ Geitz ”) begins with a cataphyllary leaf and witli
prosent/iesis. The “Lotten” grow all through the Sum-
mer, and often on until late in autumn, forming a chain,
endless in its nature, which is only forcibly broken off by
the commencement of winter. I have counted as many
as twenty-six constituent joints (tlius twenty-six tendrils
and about forty leaves) in strong “ Lotten The
“Geitzen” also die away at the point in winter; the
weak and late developed often even down to the base, so
that only the cataphyllary leaf with its axillary bud
remains. This lowest part of the “Geitz” is of especial
importance. In the axil of the basilar cataphyllary leaf
of the basal-sprout of the “Geitz” is found a bud (as
stated above, in describing the condition in the first
year) ; this bud begins with two firmly-connected cata-
phyllary leaves, and endures through the winter in the
closed condition. It is this resting-bud from which the
series of generations of the “Lotte” and indirectly the
formation of “Geitzen” is repeated in the next year.
It is, therefore, first of alla “Lotte” bud, and, if the vine
has attained the proper age, which is usually in the fiftli
or sixth year, at the same time a bearing bud, since the
inflorescence appears at the lower parts of the “Lotte”
in place of the previous tendril-formation. In this casc
numerous hypsophyllary leaves occur in place of the
single hypsophyllary leaf of the tendril, and the axis ends
in a terminal flower ; by graduated ramification from the
axils of the hypsophyllary leaves arises, thcn, the richly
panicled blossom of the grape, which, in Opposition to

4

50

THE THENOMENON OE

ordinary botanical language, is commonly called a
“ troube ” (raceme).

When we seek to separate tlie essential and inessential
sprouts, in this complicated biography of the vine, which
could only be given in very rough outline kere, we might
be inclined to see in the rcpeated succession, not of mere
simple generations, but even of whole chains of genera-
tions, as occurring in the “ Geitzen ’ and “Lotten,”
clearly essential arrangements of sprouts, because the
same are necessary transitional links to the attainment of
flower and fruit ; but if avc take the essential succession
of sprouts, in the sense explained in the preceding pages,
as a scries of partially endowed, reciprocally complemen-
tary sprouts, we must rather acknowleclge that the vine
is essentially only uniaxicil, since it produces all the
essential stages of metamorphosis on one axis, as we see
them represented in the basilar sprout of the fertile
“Lotte” which includes cataphyllary, euphyllary, hypso-
phyllary, and flower formations. All the rest of the
members of the succession of sprouts are either prepara-
tory representatives of the same series of formations not
fully attaining the goal, or imperfect repetitions of these.
But how charactcristic is this varied rise and repetition,
this linking into a complicated succession of sprouts, in
the developmental history of the vine, and how essentially
it lays down the conditions under which this plant can
live and grow ! It is true that if we compare the ordi-
nary methods of cultivation, adapting the vine to our
conditions by systematic crippling, we might wonder at
the abundance of superfluity which the vine annually
produces. The “Geitzen” are carefully broken off, and
the long luxuriant “Lotten” cut back to a few joints !
In the south, on the other hand, when the vine appears
as a widow, when not supported by the lofty elm, we see
how this superfluity essentially belongs to the economy of
the vine; when left to its freedom, it twines itself over
the highest trees.

Thus, then, we see that mucli as the law of superfluity

REJUVENESCENCE IN NATURE.

51

prevails in the formation of sprouts in plants, as it cloes
everywliere in nature, yet all formation of sprouts, the
inessential no less than the essential, possesses a deter-
minate relation to the maintenance and progressive de-
velopment of the plant. From the consideration of the
sprouts as individuals, the vegetable “ stock” must appear
to us as the living trunk of a family, rejuvenised and in-
creased according to determinate laws of propagation,
the differently gifted members of which family we have
endeavoured in the foregoing, though only in mere
indications, to represent, as arranged according to descent
and collateral relation, in their either closer (direct) or
looser (indirect) relation to the destination of the whole.*
And thus may the import of sprout-formation become
clear, as a subordinate propagation, subserving the indi-
vidual destination in its wider sense. The undeniable
interweaving of propagation and development within this
circle, may at the same time form an acceptable guide to
the destination of the individual in the larger circle of the
species, as well as that of this again in the totality of the
series of organic creation, f which has already been re-
ferred to in the Introduction.

II. — LEAF-FORMATION.

From the Rejuvenescences which the plant experiences
through formation of sprouts, by which the subject (or
theme) of the plant is many times repeated and variously
distributed on the “stock,” in subordinate individual

* The study of sprouts is the broadest and fairest field in Morphology, but
as yet, unfortunately, the least cultivatcd. What. C. Schimper long since
accomplished in this department, but has not yet published, I lmve already
mentioncd in a public lecture on “ the Yegetable Individual,” which I shafi.
print after this discourse. The phenomenon of the essential and necessary
succcssion of sprouts long known in the vegetable kingdom, agrccs com-
pletely with that occurring in the animal kingdom, the so-called alternation
of gcnerations, brought into its true position chiclly by Sars and Steenstrup.
I have shown this by a dctailed comparison in the above-mentioncd lecture.

t Victor Carus has given important liiuts upon the analogy of the alter-
nation of gcnerations with the succcssion in the series of organic beings,
in his before-mentioned Essay ‘Zur Näheren Kenntniss des Generations
Wechsels,’ p. 54.

52

THE PHENOMENON OE

structüres, we pass to the examination of the phenomena
of Rejuvenescence in the individual sprouts themselves.
The single links of Rejuvenescence which we raeet
here, are the leaves built up successively one above
another, separated and at the same time held together
by stem-formation, forming, as it were, the persistent
waves of the vegetable life, flowing towards its goal in
alternating rise and fall, concentration and expansion.
But before considering tliese separate Rejuvenescence-
waves of the sprout, represented in the formation of
leaves, we must examine the greater, upward-striving
periods of the metamorphosis (which contain the smaller
waves within them), as they manifest themselves in the
conditions of the successive leaf-formations.

Previously, however, to tracing the great tide of the
ascending metamorphosis and its subordinate waves, we
will connect this entire section with the preceding, by a
minute examination of certain cascs of descending and
vibrating metamorphosis. It has beeil remarked above,
that not every sprout carries the metamorphosis towards
the goal, that in fact not merely a normal persistence at
particular formations occurs, but in certain sprouts even
a retrogression.* By such a retrogression the sprout
recurs, as it were, to the commencement of its theme,
becoming renovated and rejuvenised in repetition of the
impulse, but giving up as a prcy to age the relinquished
product of the earlier period of growth. In fact Rejuve-
nescence of the sprout itself bears great resemblance to
the Rejuvenescence by the formation of new sprouts ;
indeed, in a physiological point of view, and in reference
to the vital economy of the plant, these two kinds of
Rejuvenescence are of equivalent import. Botli stand
related in the same way to the perioclicity of the seasons,
in both cases is seen the same independence of the
new formation of the foregoing structures. As in the
formation of lateral sprouts, the chief sprout from which

* See page 31.

REJUVENESCENCE IN NATURE.

53

tliey are sent out either dies {Solanum tuberosum, Saxi-
fraga granulata), or becomes a liiere supporting and
subservient scaffold, to a certain extent a soll for the new
generation, so in the Rejuvenescence in the sprout itself,
we again find these two cases, since the fore-running
part of the sprout soinetimes dies away, sometimes be-
coines the support of the rejuvenised continuation. The
first case is seen in all root-stocks dying away at the
posterior end,* * * § as also in bulbsf dying away externally
and becoming rejuvenised in the centre; the latter we
find especially in woody plants which possess terminal
buds. On the other hand, tliere is the essential dis-
tinction, in morphological respects, between the two
cases here compared, that in the one case the renovated
vital movement is undertaken by really new individuals
(lateral sprouts), while in the other cases the same indi-
viduals (the old sprouts), rise up to new vital activity,
which distinction has already been remarked upon above,
in the introductory consideration of the buds.j Moreover
tliose sprouts which are incapable of advancing to the
uppermost stage, do not in all plants possess the power
of Rejuvenescence through retrogression to a lower stage
of formation, i. e. the power of forming terminal buds
destined for the succeeding period of Vegetation ; t.his is
ratlier, indeed, a privilege of but a few perennial herbs
with subterraneous perennial Stocks, and of a portion of
the woody plants. § Among those which possess this
power, again, two cases have to be distinguished : either

* Anemone nemorom , Epimedium alpinum.

t Narcusus, for example. The terrestrial species of Isoiiles , particularly
/. hyttrix and I. Durieei, afford an especially fine instance of tliis kind. See
my description of them in tlie ‘Exploration Scientifique d’Algerie.’

\ Distinction of lateral and terminal buds, pp. 18-20.

§ Formation of terminal bud3 does not occur, for instance, on the middle
leai-bearing chief sprout of Urtica urens and Mercurialis annua ; since these
plants are also devoid of lateral buds, tliey die away altogether aller Ihe
fruit is quite mat.ured. Urtica dioica and Mercuriulis perennis die down
only to the cataphyllary region, from which arise the cataphyllary sprouts
Iasting over the winter. Carpinm, Salix, Ulmus, Morus, Macluru, Tilia,
Diotpyros, and Calycanlhus, are examples of woody planls without terminal
buds.

54

THE PHENOMENON OE

the sprout, after many years’ Vibration, runs througb, as
it were by a fresli impulse, to the goal, and thus con-
cludes its growth, or it sinks back again to infinitv,
after each new flight upward. Both kinds of behaviour
are represented not only among woody plants, but also
among perennial herbs and bulbous plants. In Querem ,
Fagus , Fopulus , Xglosteum, and Caniellia, all the euphyl-
lary sprouts return at the tops to catapliyllary formation,
continuing their growth in the following year from the
terminal bud, witli a new euphyllary shoot. They acquire
by this the power of infinite growth, whicli indeed finally
finds obstacles in old trees, but is made good by taking
off slips and grafts. If we compare with these, Acer,
XEsculus , Juglans, Rhododendron, &c., we find the same
condition during a more or less extensive series of years,
but at last, wlien the growth has elevated the plants
sufficiently above the earth, the shoot is sufficiently in-
vigorated and limited by repeated periodical renovation.
It does not return to the formation of catapliyllary leaves,
but advances to the formation of the inflorescence (with
or without a terminal flower), and then comes to the end
of its growth. In Juglans, only, the female inflorescence
is attained in this manner, while the male catkins appear
as lateral branches. Rhododendron is remarkable, from
the fact that the terminal shoot of the sprout, which
appears (on branches of full-grown “Stocks”) mostly in
the third year, consequently after two intermissions
{Absätze) with catapliyllary and euphyllary formations,
overleaps the euphyllary formation, and passes at once
from the catapliyllary leaves (bud-scales of the last ter-
minal bud) to hypsophyllary formations, the bracts from
the axils of which the flowers arise. Side by side with
the first-named examples (with infinite rising and sinking
Rejuvenescence), we may place Ilepalica, Adoxa, and
Oxalis Acetoselia, from among the perennial herbs. The
Tlepatica every spring produces a bud composed of eight
scale-like cataphyllary leaves, followcd by three euphyllary
leaves ; after this, it recurs to the formation of a similar

REJUVENESCENCE IN NATURE.

55

terminal bud. The flowers arise laterally from tlie axils
of the cataphyllary leaves. The Adoxa , on the contrary,
creeps along under ground with a slender stem, rising
above the surface every spring to bring forth, after an
indefinite number of small, tooth-like, cataphyllary leaves,
one to three (mostly two) long-stalked euphyllary leaves,
from the axils of which arise the flowering stems, with
two smaller, sessile, euphyllary leaves, and the head of
flowers. Between the two long-stalked euphyllary leaves
the stem recommences its growth as a descending runner,
repeating the same process in the follovving spring, and
so on, ad infinitum. Ilelleborus niger, Anemone nemorosa,
Epimedium, Actaa, and Pyrola , may be mentioned as
examples of another kind of growth. I will describe the first
two somewhat minutely, for comparison with Hepatica and
Adoxa ; the short ground-stem or root-stock of the black
hellebore annually produces one single euphyllary leaf,
which is succeeded by a terminal bud of two to four cata-
phyllary leaves. After alternating in this way for four
or five years, the euphyllary formation is skipped over,*
or only imperfectly indicated, and the plant attains the
hypsophyllary and floral formations, and then rises up
above the alternating euphyllary and cataphyllary leaf
regions through the elongation of the flowering stem.
ln iike manner, Anemone nemorosa prolongs its creeping,
subterraneous growth, with alternations of euphyllary and
cataphyllary formations, for several years before it arrives
at flower terminating the slioot. The number of annual
cataphyllary leaves on the horizontal rhizome increases
from year to year, rising gradually to eight, and each of
these preparatory sections terminates with a single long-
stalked euphyllary leaf, tili, finally, the last section, after
producing its proper number of cataphyllary leaves, rises
into an upright shaft, producing the three-leaved wliorl
of euphyllary leaves and the nodding flower. Among

* As in Rhododendron (sce above) and Pyrola.

56

TIIE PHENOMENON OF

bulbous plants, the narcissus and its allies, the snowdrop,
on the one band, the tulip and onion (. Älliuni ) on the
other, may furnish examples. Narcissus poeticus, when
arrived at a flowering age, annually produces a sheath-
like, closed, cataphyllary leaf, and four euphyllary leaves,
the last of which, bearing the flower in its axil, is devoid
of the embracing slieath of the preceding. As long as
no axillary flower is produced, the innermost euphyllary
leaf of the annual cycle possesses a slieath. Leucojum
vernum , similar in other rcspects, has only three euphyl-
lary leaves, the middle one being that which bears the
flower, and is devoid of a slieath ; the third, which has
again a slieath, is thus alrcady on the retreat back to
the cataphyllary formation. In Galantkus ?iivalis the
annual cycle is composed of one cataphyllary leaf and
two euphyllary leaves, the upper of these two being
without the slieath, and witli a flower. While in the
licart of the bulb of this plant one annual cycle succeeds
anotlier in an infinite series, the product of the earlier
years dies away, pari passu, at the periphery of the bulb,
since not only does one slieath after anotlier dry up and
moulder away, but also the base of the axis of the bulb
tlirows off the superannuated part by exfoliation. The
old circles of roots are also tlirown oft“, and replaced by
new. The tulip displays a different character. While
in the narcissus the flower arises as a lateral sprout, in
the tulip the heart of the bulb itself shoots up, after
mostly three tubularly closed cataphyllary leaves, into a
ffower-stem witli euphyllary leaves. But before this
happens, the development alternates for several years
witli cataphyllary and euphyllary formations, annually
sendin g above ground only one euphyllary leaf, and tlien
returning to cataphyllary formation in the centre. Witli
this frequently occurs the remarkable case, that, in buds
not yet arrived at sufficient maturity to produee flowers,
the central bud of the bulb sinks down into a descending
spur, formed out of the inclosing base of one of the

REJUVENESCENOE IN NATURE. 57

preceding leaves, in this way leaving the old bulb and
descending deeper into the bosom of the earth.*

A retrogression from the hypsophyllary formation to
the euphyllary, or even to the cataphyllary formation» is
far more rare than the periodical sinking from euphyllary
to cataphyllary formation. Ananas affords a normal and
universally known example of this case, the summit of
the inflorescence returning to the euphyllary formation,
attaining complete Rejuvenescence in the “crown,” as it
is called, and when this is removed and planted producing
new blossom and fruit in the third year. The same phe-
nomenon is exhibitecl by the New Holland genera of
Myrtacece , Melaleuca, Callistemon , Beaufortia, and Calo-
thamnus, the brush-like spikes of which owe their stränge
“ growing-through,” or innovation, to a similar recur-
rence to the formation of an euphyllary slioot from the
end of the hypsophyllary region. What are called the
viviparous grasses, e. y. Poa bulbosa and P. alpina, which
occur only in this condition in many places, and behave
like Ananas , migkt appear as paradoxes, but here it is
really the hypsophyllary region which is made into an
euphyllary region by a retrogression ; t and the tufts of
euphyllary leaves arising in this way subsequently become
detached, to recommence the ascending development as
independent Stocks. At the same time the behaviour of
these grasses is not that natural to the species, but that
of a monstrosity become a variety. Leafy shoots occur
not unfrequently, as a mere accidental monstrosity, at
the summits of inflorescences: I liave seen them especially
tine in Plantayo lanceolata , where the leafy slioot at the
end of the spike became developed into a new perfect
stock. Even in flowers, retrogression of this kind occurs
as a malformation ; well-known garden examples are

* This is not the place for a rninute description ot'this stränge phenome-
non. The description of it given by Henry, ‘Nov. Act. Cur./ vol. xxi, p. ] ,
leaves some questions still open, which I shall take upatanotheropportunify.

t The lowest glumes of the spikelets are mostly unaltered here, many of
them eveu having flowers in their nxils. Vide Mold, ‘ Bot. Zeit./ 1845
p. 33, t. i, fig. 2.

58

THE PHENOMENON OE

furnished by the roses, where the stem grows onward
through the middle of the flower, and the Digitalis
purpurea monstrosa* in which the terminal flower is
grown through in the same way. The female liead or
cone of Cycas may be regarded as a flower normally
grown through, with a retrogression from the (certainly
very imperfect) carpel-formation to the cataphyllary and
euphyllary formations. In Cycas , before the age of
blossoming, girdles of scale-like cataphyllary leaves alter-
nate in regulär Order with girdles of pinnate euphyllary
leaves, which latter at all times form the crown of the
tree. This alternation has, in our botanical gardens at
least, a biennial period, so that the crown of euphyllary
leaves undergoes Rejuvenescence every two years. When
the fruit-bearing age arrives, this alternation becomes
more complicated, the Order being as follows: 1, a zone
of cataphyllary leaves (forming before the unfolding of
the succeeding parts a large, shortly conical, terminal
bud) ; 2, a zone of euphyllary leaves ; 3, another zone of
cataphyllary leaves ; 4, a zone of spathulate seed-bearing
leaves (carpels), originally packed together in a conical
form, afterwards spread out. ln the centre of this head
or cone, representing the female blossom, is formed a new
cataphyllary bud, with which begins anew the whole
cycle of Rejuvenescence, and this is repeated as long as
the tree exists.f

I will not close the examination of these points with-
out remarking, that such periodical Rejuvenescence con-
nected with the alternation of the seasons, is not always
combined with so decided a retrogression of the meta-
morphosis as in the above-mentioned examples. The
retrogression to cataphyllary formation, in particular, is
very frequently absent (but not universally) in the trees
of more Southern regions, in which the place of transition
from one yearling shoot to another is merely marked by

* Yide the ‘Flora/ 1844, No. 1, t. i. _ ..

t Vide llheede, ‘ Hort. Malabar/ in, t. xiu, xx, especially t. xvn, where
this growing-through ol the lemalc blossom is represented.

REJUVENESCENCE IN NATURE.

59

sraaller euphyllary leaves, as for example in numerous
New Holland Myrtacece, as also in the South European
myrtle. While our firs and pines annually retrograde
to cataphyllary budding, wefind the limits of the yearling
shoots of the more Southern Conifers of the genera Arau-
caria and Cunninghamia , marked merely by smaller
euphyllary leaves. Many evergreen plants, however, of
our own climate, exhibit an exactly similar behaviour, as
for instance, Juniperis communis and Ly copodium anno-
tinum , in which the y early lengths are only to be deteeted
by contracted places on the closely-leaved shoots. Among
herbaceous plants, Lysimachia Nummularia * and Isnardia
palustris belong here, tliese proionging their creeping
stem by a considerable piece every new year, while the
lengths of the previous years die away. Veronica Cha-
mcedrys has the peculiarity herewith, that the euphyllary
shoot, from which the inflorescences go out laterally as
second axial Systems, is erect until the time of flowering,
and only bends down its elon gatin g end to the earth
after the plant has flowered, striking root then to ascend
again in the following year and bear flowering branches.f
In Gleckoma liederacea, also, the shoots which are erect
until the time of flowering, turn back, at least in part,
towards the ground, not however to ascend again in the
next spring, but to send only branches upward.|

The simplest mode in which the periodical Rejuve-
nescence presents itself to us, is that in which the same
sprout annually produces only one new leaf. Thus in
the brake fern ( Pteris aquilina), which annually sends
forth from its subterraneous creeping rhizome only one
of its distichously-arranged leaves, not unfolded until the
third year, an euphyllary leaf, often of enormous size,
and pinnatifid in beautiful gradation up to the fourth
degree. So again in the Ophioylossum, already men-
tioned { above, and at all events in our greenhouses the

* Vide A. de St. Hilaire, ‘Lepous de Botanique,’ p. 103.

t Ibid., p. 105.

% lbid., p. 105. § See ante, p. 18.

60

TI1E PIIENOMENON OF

large-leaved Coccoloba pubeseens. These cases lead to
the individual leaf, as a link of Rejuvenescence, the in-
vestigation of which, however, must be preccded bv the
consideration of one point more.

The rejuvenising force and activity of vegetable life
does not display itself merely in the particular cases of
periodical, retrogressive, or alternately advancing and
receding metamorphoses, such as we have just examined ;
it shows itself also in the ascending metamorphosis, in the
advancing series of formations, such as occur as the
universal types in the higher divisions of the vegetable
kingdom. Here occurs, in the closest connection with
the progress from stage to stage, an alternation of
vigorous advancc and checking retraction, an increase, a
decrease, and a renewed rise of the energyofthe outward
reprcsentation, a Rejuvenescence in the truest sense of
the word, since liere with every new onward flight of the
old being, the plant appears not in mere repetition of the
old form, but by deeply grounded renovation, in a more
perfect and more expressive shape. This it is which,
since Goethe’s time,* has been called the metamorphosis
of plants, a term borrowed from the transformation of
insects, which has however given rise to mistaken views, f
but is capable of being made the basis of a more pro-
found conception of the phenomenon. Goethe himself,
although his theory of metamorphosis is mixed up with
various obscure elements, pointed out many features of
the more profound side of the question. He speaks of
the metamorphosis of plants not merely as of a series of
outward phenomena of transitions between the different
structures, but as of an inward principle of the formative
process advancing from one modification of form to
another. Inliiseyes the metamorphosis was a force which
might be observed ever acting with a graduated power

* ‘Versuch die Metamorphose der Pflanze zu erklären,’ Gotha; 17‘JO.

t That Goethe was not even free from tlic erroneous notion tliat one organ
of a plant might he actuallv transformed into another, c. g. stamens into
petals, or ova'ries into leaves',' is evident from the very tirst paragraph of his
J ntroducfcion.

RE.TUVEN ESCENCE IN NATURE.

61

from the first seed-leaves to the final maturation of the
fruit, and, by the conversion of one form into another,
leading np to the highest point of vegetable life, as it
were, by an ideal flight of steps.* This ideal flight of
steps which Goethe perceived in the metamorphosis of
piants, is a speaking testiinony of the profound con-
ception of it entertained by him ; for that which leads
the formative process of the plant from one stage to
another, which connects the steps of the series, which
causes each succeeding step, although separated from the
preceding, to appear as a stage of conversion of the
latter, can in reality be only an inner and ideal bond.
Only the inner identity of the natnre of the plant,
through all the change of ontward manifestations, can
justify us in regarding the gradually advancing Rejuve-
nescences as really a metamorphosis, that is, a series of
transformations of an essentially identical element. In
this sense Goethe spealcs, too, of the mysterious affinity
of the different external organs of piants, pointing out
that the real identity of the organs corresponding to each
other at the different stages can indeed only be deduced
from that inward connection of the steps of the meta-
morphosis, and not from mere outward resemblance.

Goethe already directed attention to the great vibra-
tions of the metamorphosis which we here first examine,
since he speaks of an alternation of expansion and con-
traction in the successive leaf-formations.f This is one
of the most important factors in his attempt to explain
the metamorphosis of piants ; for a minute discussion of
which, however, it is necessary that we should cast a
hasty glance over the series of the leaf-formations them-

* Viele Goethe, 1. c. § 6.

t Goethe, 1. c. “ From the seed up to the highest development of the
stem-leaf, we observed ürst an expansion, after which we saw the calyx arisc
from a contraction, the pctals from au expansion, the reproductive organs by
another contraction, and shall now soon make out the greatest expansion in
the fruit and the greatest contraction in the seed. ln tliese six steps
Nature eompletes, without pausing, the eternal work of the propagation of
vegetables.”

62

THE PHENOMENON OE

selves. The metamorphosis of plants exhibits three
principal divisions : 1, the “ stock, ” or as it is termed in
plants not forming wood, the herb {herauf) ; 2, the flower;
3, the fruit. The first two divisions are again divisible
each into three stages, wliile the third principal division
does not admit of further analysis. Thus we obtain
from 3 + 3 + 1 the number 7 for the stages of form in
plants. The character of these seven sections or regions
is chiefly expressed in the graduated change of shape of
the leaf, while the stem takes a less striking, though still
considerable share in the transformation from step to
step. We shall therefore consider the steps of the
metamorphosis more particularly in regard to the
behaviour of the leaf, as it presents itself at the different
heights upon the plant, applying to the more essential
gradations which are distinguishable the denominations
of so many leaf-formations. As a general rule, as already
stated, there are seven of these, which, however, do not
exhibit perfect representatives in every plant, for their
number may be lessened either by imperfect differentia-
tion, or by falling short of or overleaping forms.

1. The cataphyllary formation {Nieder-blatter), to
which bclong the scales and sheathing leaves of subterra-
ncous or aerial buds, bulbs, runners, and tuberous rhi-
zomes. They are remarkable from their broad basis,
small height, and most simple shape and nervation;* they
have no laminae, no stalks, no subdivision, f consequently
never have stipules, and are constantly entire. Their
consistence is often fleshy, cartilaginous or leathery, in

* In dicotyledonous plants even these are mostly parallel-nerved, and the
parallel-nervcd appearance of the cupliyllary leaves of the monocotylcdons is
out a sign that the euphyllary leaf-formation is less characteristically deve-
loped in them, and hence is more like the cataphyllary formation than is the
case in the dicotyledons.

f There are exceptions to this in the cataphyllary-leaves separating into
two distinct scales, in the buds of certain trees, e.g., Betula, Carpims, Corylus,
Fagus, and Quercus. This structurc may be regarded as a transition towards
the euphyllary-leaf formation, the leaf being here divided into two stipules
and an abortive central leaf. In Quercus the first bud-scales are still
undivided. These conditions are described by Doll,— e Zur Erklärung der
Laubknospen der Amentacen,’ 1848.

REJUVENESCENCE IN NATURE.

63

rare instances they are delicately membranous, in which
cases the axis which bears them is mostly fleshy j their
colour is nevera decided green, generally whitish, passing
iuto yellow, flesh-colour, brownish, or even black. Their
development goes on very slowly; they are tolerably en-
during, and the cliief part of their existence is passed in
the winter season.

2. Euphyllary formation ( laub-blatter ). — These are
the Organs, especially and ordinarily simplycalled “leaves,”
which give most character to the vegetative structure or
stock. They are readily distinguished from the leaves of
the preceding formation by the greater longitudinal
development with a narrower base, in general more con-
siderable dimensions, and the green colour, never absent
although in many cases concealed. Their especial mark
is the blade-structure, with which is ordinarily combined
its contrary, the stalk or petiole structure. Through
multifold alternations of the conditions of expansion and
contraction arises the so frequent production of divided
and compound euphyllaiy-leaves, to which also belongs,
as a special case, the division into main- leaf and accessory
leaves (stipules). The multiplicity of conditions of ner-
vation within the body of the blade, corresponds to the
multiformity in the outline of the leaf. The consistence
is mostly stoutly membranous, frequently leathery, more
rarely fleshy. The principal part of the life is passed in
the summer ; the duration is considerable, especially in
those of fleshy or leathery consistence.

3. llypsopJiyllary formation ( [Ioch-blätter ), to which
belong the involucral leaves and common calyces ofinflo-
rescences, bracts and bracteoles, glumes and paleas, which
accompany the flower. These again approach in charac-
ter the cataphyllary leaves, as the stalk and blade-struc-
tures, as well as the green colour, vanish more or less or
even quite completely.* They are distinguished from

* Stalked hyp3ophyllary-leaves arc a rarity, e. ff., in Podolepis; the
formation of a stalk occurs more frequently above the sheath-like part of the
leaf, as for instanee, in the formation of awns on the glumes of the grasses.

64

THE PHENOMENON OF

the cataphyllary-leaves cliiefly by the narrowness of tlie
base, more delicate structure, and raore rapid formation
and decay.

4. Formation of the calicine-leaves (sepals) . These
form the first proper envelope of the flower, and are
again thicker, tougher, and greener than the npper-leaves,
mostly have a broader base, little or no laminar expansion,
no stalk-fonnation, and are either simple or but slightly
divided.* They are mostly more enduring than the
succeeding formations of the flower, they often outlive
these, and frequently take part in the formation of tlie
fruit.

5. Formation of the corollinc-leaves (petals), strikingly
characterised by delicacy of texture, beauty and variety
of colour, with the exclusion, however, of green. As a
rule, they are longer than the sepals, but have a
narrower base ; mostly exhibit an extensive laminar por-
tion but no distinct stalk-structure, often radiant or
forked, but very rarely pinnate, division.f Excrescent
growths doubling the limb or laminar structure ( einer -
gcnccs ) sometimes occur upon the surface of the petal,
as in Narcissus, Nerium, Ljchnis, or longitudinal wing-
like edges, as in Saponaria, Ägrostemma, and the Hydro-
phyllacese.

6. Formation of the pollen-leaves (stamens), com-
prising the smallest and thickest leaves of the flower,
characterised by distinct stalk-formation (filament) from
the narrowest base, with a box-like expansion of the
lateral lialves of the little developed blade ( anther ) .
Folding over of the blade ( Ueber spreitung), which occurs
but rarely in the petals, is here almost an universal rule,
whereby the chambers of the anther become doubled on
each side. They are distinguished above all the other
parts of the flower by the most rapid completion of the

* Sepals with pinnse {Rosa), with stipules (Pegamm), or with a ligule-
structure ( Mesem bryant hem u m ) , are rare cxceptions.

-(• Ex. gr. Schizopetal wn. Dnimmondia.

REJUVENESCENCE IN NATURE.

65

structure, and the greatest perishability aftcr tlie opening
of the blossom.

7. Formation of the Fruit-leaves (carpels). These are
again larger, thicker, greener 'than preceding parts,
bnt especially distinguished by the permanent folding
together, passing into confluence. Springing from a
narrow base, the lower part expands like a blade, forming
the cavity of the fruit by closing together its own borders
or coalescing with the neighbouring carpels, while the
upper part is mostly drawn out (stalk-like) into the style.
From the inside of these leaves arise the little seed-sprouts
(ovules), so that they become the cases of the seeds,
running through with these a process of development
(maturation), prolonged far beyond the life-time of the
flower, and often requiring even more than one year for
its completion.*

To those who have studied Comparative Morphology
in an unprejudiced manner, there can be no debate on
the question as to whether all the structures of these
seven formations are really leaves. On this side the theory
of metamorphosis Stands on a firm and unshakeable
foundation.f But the structure which is to be erected
on this foundation, the theory of the formations, giving
the true representation of the vital history of the plant as
it is displayed in the successive transformation of similar
fundamental organs, is as yet unfortunately scarcely dimly
shadowed forth. It is a problem which appears so much
the more difficult the nearer we try to approach to its
solution, for it then is not sufficient to mark the characters

* The ripening of the fruit and seeds occupies two seasons in mauy Conifers
( Juniperm communis, Pinus,) and mauy oaks ( Quercus Cerris, Suber, rubra, &c.)

t Wigand (‘ Kritik und Geschichte der Lehre von der Metamorphose der
Pflanzen,’ 1846, p. 118 ,) very correctly calls “ the great law of the unity of
all axial and of foliai* organs,” the nuclcus of the doctrine of metamorphosis,
remaining behind when we have subtracted the multifold and stränge clotli-
ing with which it is ordinarily cnvelopcd. On the other liaiul, the problem
of giving to the discovercd nuclcus its true natural Investments, docs not
appear to be sufliciently rccognised. Multiplicity will not be wanting in the
true clothing, and we shall certainly liavc to own to strangencss and oddity
in nature.

5

66

THE PHENOMENON OF

of the formations by comparison of externa! forms, which,
trom the multiformity prevailing in tlie vegetablc kingdom,
is an endless task ; for the true characteristic of the forma-
tions must be at the same time an in ward one : it must
comprehend the outward product in its relation to the
inner vital tendencies, entering into conflict with the
externa! worid, — and thereby endeavour to represent to
us the developmental history of vegetable life according
to the inner causes leading through all the external com-
plications. That the above short description of the leaf-
formations cnn raake no claim to such a character as this,
need not be said ; it is merely intended to bring forward
a few pcculiarities calculatcd to makc evident the regulär
alternation of rise and fall in thecourse of metamorphosis,
its succcssive “accessions” or “flights” {Aufschwünge),
which we desire to examine liere as phenomena of Reju-
venescence. The peculiarities which wc liave chiefly to
keep in view liere arc, — the relative size of the leaf in
general ; then, in particular, the breadth of the base in
proportion to the circumference of the stem ; the height
or length of the leaf ; the development in breadth above
the base (the lamination), and its opposite, the contraction
into stalk-formation, on the contrasted proportions of
which chiefly depend the further working out of the
forms of leavcs ; finally, the solidity or delicacy, and the
persistcnce or caducity. Even the most superficial ex-
amination reveals clearly that the path through the
formations from “ stock” to flower, and again from flower
to fruit, does not ascend uniformlv, that it does not
exhibit either an uniform decrease in the perfection of
the organs, or an uniformly increasing refinement of their
structure. The assumption of a single rise and fall in
the perfecting of the leafiformations, the highest point of
which should fall in the middle (the euphyllary formation),
is equally opposed to experience, for even the flower, and
still more the fruit, contradicts this view.* It is, indeed,

* Agardli goes so far on this false hypothesis, as to rcgard the higher

REJUVENESCENCE IN NATURE.

67

unmistakeable tliat the leaf-formations take tliree succes-
sive onward flights {Aufschwünge) in the course of the
metamorpliosis : one in the stock or body of the plant,
one in the flower, and, finally, the last in the fruit. A
close investigation of this phenomenon shows, that there
are also subordinate risings and sinkings even within the
first and second regions of elevation.

If we examine, in the first place, in reference to this
point, the conditions of breadth of the base of the leaf,
vve find on the stock or stein of the plant, from the first
to the last of its leaves, a decrease, sometimes gradual
and sometimes taking place by starts, and this decrease
is indeed so constant, that perhaps every exception might
be traced to the phenomenon of retrogressive metamor-
phosis examined above, although it is not equally obvious
in all.* But with the advent of the flovver a new increase
of the breadth of the base of the leaf frequently occurs,
the sepals exhibiting a broader base than the highest

development of the fruit consequent on fertilisation as a pathological con-
dition, a disease. (!) ‘Essai de reduire la Physiologie vegetale a des
principes fondamentaux,’ 1828, pp. 32, 38.)

* Among these exceptions is the condition of the cotyledons in the
numerous dicotyledonous plants in which the opposite half-embracing
cotyledons or seed-leaves are succeeded by alternate, more extensively em-
bracing euphyllary-leaves, or wholly or almost wholly embracing cataphyllary-
leaves, which latter is the case, for instance, in Asumm. In the mono-
cotyledons, on the contrary, the seed-leaf is always completely amplexicaul.
There appears, moreover, a stränge case in Convallaria majalis, in which a
number of cataphyllary-leaves forming closed sheaths, are followed by one
which is only two thirds embracing, (the same which bears the inflorescence
in its axil), and this is succeeded by two euphyllary-leaves, which are again
completely amplexicaul. Crocus luteus , also, and other species of this genus,
cxhibit a stränge aberrant condition to be mentioned in connection with the
foregoing. A number of completely embracing cataphyllary-leaves, closed
round into tubes, are succeeded by euphyllary-leaves, mostly arranged
according to the % position, the sheath-hke basilar portions of which are
not closed into tubes, but are conüucnt together one with anotlier in the
direction of the longitudinal path of the line of arrangement of the leaves,
(the spiral line cutting through the points of origin of the successivc leaves),
whence arises as it were a single connected spiral sheatli common to all the
euphyllary-leaves. The breadth of the base of a single leaf consequently
amounts hcre to % of the circumfcrence of the stem. These arc followed
by hypsophyllary leaves prcceding the terminal flower, the first closed into
a tube, like the cataphyllary-leaves, the second, on the contrary, open,
and only impcrfcctly embracing the stein.

68

TUE PIIENOMENON OF

hyps°phyllary-leaves. This may be observed especially
in calices with right-handed overlapping re ach in g down
as far as the base. That the breadth of this decreases
again in the rcgion of the petals and stamens, might even
bc deduced from the fact, that scarcely any right-handed
(eutopic) overlapping occur, since the overlappings do
not proceed from the base, but only arise from the over-
lapping of the petals snbsequently expanding above. The
stamens, as a general rule, never overlap, and the great
number of tliem which stand in a circle in many poly-
androus liowers, shows the narrowness of their bases.
The bases of the carpcls are not expanded transversely or
overlapping, it is true, but their smallcr number, in the
majority of cases, as well as their close approximation,
ncverthelcss testifies to the greater thickness of their
bases. The decrcasing breadth of the base in the leaf-
formations of the “ stock” may be made clearer by the
mcntion of a fcw more examples.

Tulipa. — The bulb exhibits 3 — 4, completely embracing,
tubularly closed, cataphyllary leaves, followcd by 3 — 4
euphyllary leaves on the stalk which shoots up, the
lowest of the latter being still amplexicaul and closed
round at the bottom, the succeeding embracing in a
gradually decreasing extent 2 to

Convallaria Polygonatum. — The cataphyllary leaves on
the horizontal rhizome complctely embracing, themargins
even overlapping. The first of the euphyllary leaves
occurring on the stem rising above ground embraces
almost completely, about ^ths ; the second | or §; all the
following 2.

Veratrum (: nigrurn ). — The subterrancous cataphyllary
leaves, which are best seen in autumn on the still unde-
veloped central buds of yotmg “ Stocks,” or in the lateral
buds of older “ Stocks,” are embracing, and form a cone
or cup, closed completely, with the exception of a small,
scarcely perceptible slit at the upper end, this cap being
broken through above in the subsequent unfolding of the
bud. The first six or seven euphyllary leaves have long

RE J U VENESCEN CE IN NATURE.

69

closed skeaths, reaching down to the abbreviated sub-
terraneous portion of the stem ; tliese are followed mostly
by two skeaths, also closed round, but shorter, wkick
arise on the portion of the stem skooting up. The suc-
ceeding euphyllary leaves, further separated from eack
otker, and becoining progressively narrower and shorter,
are no longer embracing, and exhibit a gradual decrease
of the breadth of the base, following sometking like the
ratio |, |, b |, 3, b |, i, and tken remaining more equal,
decreasing to | as a minimum. The leaf embracing i
is the first wkich produces a branch, the lowcst lateral
spike of the large, compoundly spicate inflorescence
arising on its axil. The small hypsophyllary leaves,
from the axils of wkick the individual flowers arise, em-
brace ^ or

Valeriana oßcinalis. — The subterraneous runners ex-
liibit white, one-sidely apiculate, completely embracing,
cataphyllary-leaves, closed into tubes by the biending of
their borders. Of the alternating, two-ranked euphyllary -
leaves succeeding tkem, the lowest have likewise a com-
pletely embracing sheathing base, wkile the last embrace
only about f. The euphyllary-leaves found on the erect
part of the stem are connected in pairs, and embrace i,
or, on the triple whorls sometimes occurring, only ±. The
hypsophyllary leaves have an arrangement similar to that
of the euphyllary leaves, but the two opposite leaves of
eacli pair do not quite reach one another witli their bases ;
they are less than b finally only ± embracing.

Ileracleum. — The lower and middle euphyllary leaves
of the species of this genus have overlapping sheaths,
therefore they reach somewhat more than completely
round the stem ; the upper, already smaller ones, having
a less divided and scarcely stalked lamina, usually approxi-
mated together, and having the umbel-bearing branches
m their axils, exhibit imperfectly embracing sheaths,
rapidly decreasing in breadth, about in the proportion
\ b h b or falling still more quickly. Finally, the small
linear, or almost bristle-like hypsophyllary leaves of the

70

THE PHENOMENON OF

involucre and involucel exhibit scarcely-^ — ~ breadth of
tlie base.

Mahonia Aquifolium. — The cataphyllary leaves (bud-
scales) are about § embracing ; the euphyllary leaves
falling to | or i ; tlie hypsophyllary leaves on the axis of
the panicle \ ; the little bracteoles (vorblätter) occurring
on the stalk of the flower itself, which, however, rarely
come to evident development, are still narrower than the
bracts (deck-blätter) of the infiorescence.

Thus the plant, as a general rule, exhibits the phe-
nomenon of decrease in regard to the breadth of the base
of the leaf, yet with two retrogressions (inconsiderable,
however), naincly, at the commencement of the flower, and
again at the close of series, in the formation of the fruit.
The following remarks will shovv that this decrease in the
breadth of the base of the leaf does not in itself indicate
any decrease in the energy of the leaf-formation, but that,
on the contrary, the expansion of the base Stands in an
antagonistic relation to the development of the middle of
the leaf.

The development of the leaf in length or height , which
is the most influential factor in referencc to the size of
the leaf generally, and the vigour which declares itself in
its formation, exhibits, in the progressive metamorphosis
of the plant, a totally different course from that of the
breadth of the base. Botli in the first and second regions,
on the “ stock” and in the flower, the longitudinal deve-
lopment of the leaf shows, first an increase and then a
decrease; the commencement of the last region, the
fruit, is connected with another increase. Thus after a
double rise and fall the terminal formation is attained in
a tliird ascent. Reviewing first of all the first region,
we find that the first cataphyllary-leaves of a sprout are
always the shortest and smallest; this rule prevails, in
like manner, in the first euphyllary-leaves of plants, or in
individual sprouts of plants where the cataphyllary leaf-
formation is wanting. The cotyledonary commencement
often fonns an exception in this respect, as in reference

KEJUVENESCENCE IN NATURE.

71

to the conditions of breadth, for tbe cotyledons of many
plants are longer and larger than the succeeding leaves
of the principal sprout, as, for example, in Quercus,
Vicia, Casuarina, Opuntia, &c. The increasing length
in the succession of cataphyllary-leaves, rnay be seen in
beautifnl gradation almost everywkere on tbe subter-
raneous buds of perennial berbs, and on tbe buds of
trees ; see, for instance, Pceonia, where tbe 6 — 7 lower
leaves *show graduated increase from 3 lines to 1± inch,*
Malionia Aquifolium , where they increase from 1 to 6
lines, AEsculus, f Rosa, j Rhododendron ,§ &c. Tbe
increasing lengtb and magnitude of stem -leaves in
germinating plants is especially well seen in Acer,
Corylus , Vitis , Phaseolm, &c. The increasing lengtb of
the leaves is mostly continued, more distinctly in tbe
eupkyllary than in tbe cataphyllary fonnation, tili it
reackes its inaximum in a determinate median region,
from wbicb an equally graduated decrease commences,
mostly prolonged even into tbe hypsophyllary region.
It depends on tbe conditions of extension of the stem
whether tbe maximum of the longitudinal development of
the euphyllary leaves lies in the lower abbreviated part
of the stem, so tbat all tbe euphyllary leaves situated on
tbe developed internodes belong to tbe decreasing series ;
or, when no such rosette-like crowding of tbe lower
euphyllary leaves exists, at a determinate height on tbe
shoot itself. | Examples of the first kind are seen in
Niyritella anyustifolia, Chrysanthemum Leucanthemum,

* Decandolle, ‘ Organographie,’ t. xxi, ßgs. 1, 3.

f Ibid., t. 20.

% Malpigbi, ‘Anat. Plant., t. xii, fig. 59.

$ Henry, ‘Knospenbilder,’ Nova. Acta. Nat. Cur., xxii, 1, t. xxii.

|| Both conditions are found combined, consequently a double maximum
in the euphyllary formation, a lower in the abbreviated part oi' the stem (ina
rosette of what are termed radical leaves), and an upper, ou the shoot,
mostly, it is true, distributed through two seasons, in many biennial plants,
e. y., Pedicularis palustris, Anarrhinum bellidifolium, (Eaothera muricuta, as
also in percnnials with biennial sprouts, e.y., Jasione perennis and Pulmonaria
officinulh. This phenomenon, however, does not properly belong liere, but
to the case mentioned above at pagc 59 of retrogressive mctamorpliosis
within the euphyllary formation.

72

THE PIIENOMENON OF

Hieracium vulgatum , Scabiosci Columbaria, Swertia peren-
nis, Aconitum Lycoctonum , &c. ; examples of the second
in Orchis globosa and maculata, Canna , Hieracium
subaudum, Gentiana germanica , Bocconia cordata, Aco-
nitum Napellus, Helleborus fcetidus, and Ruta graveolens.
Under these circumstances, when the number of leaves is
great, the increase and decrease are oftcn very gradual,
as for instance, in most species of Linaria, Linum ,
Phlox , &c. Thus in Bldox pciniculata, where the *sprout
begins with pairs of lialf-embracing subterraneous cata-
phyllary leaves, 1 — 3 lines long, and rounded off at the
top, we sec above ground about thirty pairs of broadly
lanceolate, acuminated euphyllary leaves, which are only
about 2 embracing, and attain their greatest length, of
about 3 inches, somewhere near half-way up the stem,
from which point they decrease, at first almost imper-
ceptibly, more rapidly in the inflorescence, and finally
pass into the hypsophyllary formation. The last finely-
pointed hypsophyllary leaves are only about 3 lines long
and scarcely * embracing. In other cases the leaf-
formation ascends to its maximum by a few large steps,
sinking down again as quickly, as for instance, in Hydro -
phyllum canadcnse. Tliis plant bears upon its Condensed
lower-stem (rhizomc) which creeps on the surface of the
ground, distichously arranged, thick, fleshy, persistent,
cataphyllary scales from \ to \ an inch long ; the last two
scales of the sprout* usually pass at their points into a
petiole- and bladc-formation, and thercfore are already
the first euphyllary leaves, distinguished however from
the following by their persistent fleshy scale-base. These
first two euphyllary leaves are already developed in
autumn before the sprout shoots up ; the first is often
only rudimentary, the second longer and stronger, at-
taining a height of 3 to 6 inches. These are followed

* Timt is t.o say, iu case it has sufficicnt force to blossom. Young plants,
and the weaker lateral shoots ol older oiics, aliernate for several years
betweeu euphyllary and cataphyllary formation, likc the examples xnen-
tioncd at pp. 54-55.

REJUVENESCENCE IN NATURE.

73

mostly by three more euphyllary leaves (unfolded in the next
spring), the first of which is seated either on the creeping
portion of the stem, or raised but a little above the
ground on the lowest part of the erect enphyllary-leaved
stem, and it is by far the largest of all, for it equals or
even exceeds in height the entire shoot, attaining a length
of a foot to a foot and a half. The two following,
sitnated high up on the stem, are, the first 9 to 6 inches,
the second 4 to 3 inches long. The hypsophyllary leaves
succeeding upon the inflorescence are totally suppressed
in tliis plant. The exaltation of the leaf-formation ex-
pressed in the euphyllary formation appears most strikingly
in the cases where this is represented by a single euphyl-
lary leaf, which is then mostly of remarkably large size.
Thus in Epimedium alpinum * where the tolerably numer-
ous subterraneous cataphyllary leaves, from 1 to 5 lines
long, are ordinarily followed by a single twice or thrice
divided euphyllary leaf about a foot long, after which the
metamorphosis springs over suddenly to the small and
numerous hypsophyllary leaves, the length of which
amounts at most to 1 line, and sinks to gd of a line. There
is somewhat of a deviation from the usual position of the
maximum of development in length of the leaves, in the
rare cases where this occurs at the end or the beginning
of the euphyllary formation, instead of in the middle.
We see the first case in Ileliconia cannoidea ,f in which
the decrease of length commences in the hypsophyllary
formation ; the last in Pceonia and Actcea. The bane-berry
( Actaa spicata) presents on the subterraneous stock several
short-sheathed cataphyllary leaves, increasing in length
from 1 to 3 lines ; to these succeed, upon the erect stem,
mostly three euphyllary leaves ; the lowest, largest, very
decoinposed, is about 1 foot long, while the third,

* Other examples of one-leaved euphyllary formation are furnished by
Malaxis monophylla , and very many exotic Orchidacese ; also by many
Aroidem, e.g., Arum echinutum, (Wall. pl. as. rar. t. cxxxvi) ; by Gcsneriaccsc,
as in Platystemma violoides, (Wall. 1. c., t. cli) ; by Sanguinaria ; and lastly
by many CyperaceEc, as for example, Scirpus mucronatus.

t Richard, * Comment. de Musac.,’ t. ix.

74

THE PHENOMENON OF

uppermost and smallest, mostly ouly simply trifid, is
from 1 to 2 inclies long. The hyposophyllary Jeaves,
following the last, and from whose axils arise the flowers
of the terminal spike, are from li to 1 line long.

In conclusion, I will describe the phenomenon of in-
crease and decrease in the length and size of the leaves
upon the “stocks” of plants, in one more example,
where it presents itself in an uncommon grandeur, namely,
in the plantain (Musa).* I have not liad an opportunity
to examine the subterraneous portion of the stem of this
plant, rising upward from a horizontal commencement;
when this cornes above ground, as a young shoot, we at
first see a few cataphyllary leaves, which are probably
preceded by a considerable number Underground. In
M. sapientum they are acuminated, triangulär, Shilling,
dark-brown leaf-sheaths, which manifest the commence-
ment of the euphyllary formation by the commencement
of pctiole- and blade-formation at the summits. Not
only the sheath but also the stalk and lamina now grow
longer, from leaf to leaf, until the well-known splendour
and magnitude of the plantain leaf are attained. The
complete development of the sprout of a plantain re-
quires with us several years, in its tropical home at most
two years ; the outer leaves die away as the inner unfold.
All the leaves of a shoot which has not yet sliot forth
into blossom, arise close to the ground on an abbreviated
stem, and, simply by the rolling of their sheaths round
one another, form a tall pseudo-stem, wlience Richard
called Musa a bulbous plant. Consequcntly the length
of the leaves liere determines the height of the entire

* The following Statements are clerived from two species in the botanic
garden of this town (Freiburg), one large, with overhanging iuflorescence
and numerous flowers in the axils of bracts, which appears to be Musa
sapientum, and a smaller, with erect inflorescence and beautiful rosy bracts
with only three flowers in eacli axil. In our garden this bears the name of
M. rubra. On this especially have I been abie to investigate miuutely the
distribution of the leaves upon the stem in rcfercncc Io height. The
arrangement of the middle-leaves is 7 in both, oi the bracts y. ln the
Statements of the conditions of length of the two species I shall distinguish
them as M. sapientum and M. rubra.

REJUVENESCENCE IN NATURE.

75

plant. Under these circumstances the innermost leaves
are the longest ; in M. mpientum I have found them as
niuch as 25 feet long, of which the sheath made about
13 feet, the petiole 2 feet, and the blade 10 feet. In
M. rubra they are only about 15 feet long, the petiole
being longer in proportion than in M. sapientum. JFrom
the point where the stem shoots up into the slender
flower-shaft, breaking through the stem-like convolution
of sheaths, commences the decrease of length of the
leaves. In M. rubra I found as many as five euphyllary
leaves on the elongated portion of the stem, the upper
tliree of which, especially, exhibited a considerable de-
crease, not merely in the length of the sheath, but also in
that of the blade ; the last of them was only about 4 feet
long, namely, the sheath 1^, the stalk 1, and the blade
1^ feet. The internodes bearing these last five euphyl-
lary leaves measured respectively about 1 1 , 2, 3, 3 feet

in length. Not quite 2 feet distant from the point of
origin of the last euphyllary leaf, followed a transitional
leaf, about 1| feet long, and of broadly-linear, gradually
acuminated form, leading to the hypsophyllary formation;
at no more than 2 inches above this, began the long
succession of approximated, ovate, rosy bracts, the first
of which are about 5 inches long, the following sinking
down gradually to 3 — 2 inches. The lowest six bracts
of the inflorescence of M. rubra which I examined, bore
female flowers in the axils, all the succeeding bore male
flowers.* Musa also exhibits a beautiful graduation of
the breadth of the base of the leaves. All the leaves of
the lower part, up to the flowering-shoot, are completely
embracing. I found, in M. rubra, the uppermost tliree
euphyllary leaves embracing 1?, and £ of the circum-
lerence ; the transitional leaf §, the bracts of the female
flowers i to §, those of the male ±. In the plantain,
therefore, we see the leaf-fonnation ascend by gradual

* According to Rumph, in Musa paradmaca 12 to 20 bracts liave female
flowers, and 12 to 20 oftliem in eacli axil; so that a single inflorescence
bears 100 to 200 fruits.

70

THE PHENOMENON OP

stages,. from a few inclies often to the enormous lcngth
of 25 feet, and sink down again, with more rapid steps,
to about the saine brevity; to whicli it must be added,
tliat on minute examination of the earliest subterraneous
leaves of the sprout, and of the cotyledons of the germi-
nating plant, the point of departure would doubtless be
found smaller, as, on the other hand, we inay conclude,
from the file-like rows in whicli the flowers stand in the
axil of a bract, that the (in proportion to the flower) large
bracts are not the last members of the hypsophyllary
formation, but that undistinguishable hypsophyllary-
leaves (bracteolcs) exist at the base of the individual
flowers, formiug the true termination of the leaf-forma-
tion of the “ stock.”

A similar rise and fall in the lcngth of the leaves is
rcpeated in the region of the flower. The sepals are
sometimes immediately connected with the last hypso-
phyllary-leaves by their length, often by their whole
form, exccpting the usually.greater breadth; tliis is the
case in Helleborus foetidus, lluta graveolens , and Phlox
paniculata, in whicli the sepals agree almost perfectly, in
size and sliape, with the last hypsophyllary-] eaves. But
more frequently the calyx cxhibits a new increase of
length in rclation to the last hypsophyllary-lcaves. To
conflrm tliis I need only refer to the numerous plants
whicli possess bracteolcs ( Vorblätter ) on the peduncles of
lateral flowers, tliese bracteolcs being almost always very
small and slender, and even frequently almost indis-
tinguishably small ; see, for instance, Aconitum , Del-
phinium, Viola, Polygala, Colutea and other Legumi-
nosm, Molucella, Calamintha, Gratiola, Convolvulus, &c.
We can also detect tliis in terminal flowers, e. g. in
Dianthus, wliere the sepals, blended below into a long
tube, are preceded by several pairs of shorter scales ;*

* The two to three pairs of scale-like leaves beneatli the calyx of the
pinlcs increase in length in the ascending Order, and therefore belong pro-
perly to the new advance of the leaf-formation connnencing in the ilower,
forming an cpicalyx, as occurs also in the mallow.

REJUVENESCENCE IN NATURE.

77

also in Hypericum calycinum, in which the sepals of the
solitary terminal flowers are twice or four times as long,
and three to four times as broad as the preceding hyp-
sophyllary-leaves ; finally, most distinctly in Chelidonium
majus, in which the sepals are about three lines long,
while the two to three pairs of preceding hypsophyllary-
leaves, from the axils of which the lateral flowers of the
corymb arise, attain scarcely half a line. In the calyx
itself the metamorphosis usually keeps at the same stage,
so that at least no remarkable diflerence occurs among
the sepals ; yet the cases are not rare in which an evident
gradation occurs withiu the calyx itself, an increase of
length corresponcling to the succession of the sepals ; as,
for instance, in the quinate calyx of Hypericum caly-
cinum, imbricated in the § arrangement, the inner two
sepals of which are almost twice as long as the outer
two, the third being of intermediate length. The con-
ditions are similar in Polyyala, where the innermost two
sepals are not merely many times longer than the outer
three, but already exhibit the petaloid colour, forming
what are called the wings of the fl o wer.'*' In Oxyria
and the female flowers of Urtica we find a four-leaved
calyx, the outer two sepals of which are shorter than the
inner two ; in Rumex a six-leaved, with three outer
shorter, and three inner longer. Berberis has a double
ternate, MaJtonia and Podophyllum a triple ternate, and
Epimedium, a triple binate calyx ; in all these the inner
whorls are formecl of longer sepals than the outer.
Lastly, in the Cacteae, as also in Ca.lycanthus, the gradual
increase of length is exhibited most remarkably with an
acyclic structure of the calyx.

The length of the lcaf within the flower attains its
maximum in the corolla. Itis scarcely necessaryt.o illus-
trate, by examples, the proportionate lengths of the
corolla and calyx ; and the assertion that the petals are
longer than the sepals in the majority of plants possessing

* The same occurs in Dipterocarpns.

78

THE PHENOMENON OE

corollas, will not be contested although we omit to
demonstrate it by a nuraerical comparison, which of
course would have to be based on a determinate and
perfectly known flora. Splendid and conspicuous exain-
ples of it are furnislied by the genera Datura (e. g.
D. arborea ), Convolvulus, Gentiana (e. g. G. acaulis),
Campanula, Cucurbita , Pceonia, Dillenia, Hibiscus , &c.
This relation holds good also in small-flowered plants, as,
for instance, in Vitis, in the Umbelliferse and the Com-
positae. Even in the Monocotyledons, where generally
speaking the abrupt differcntiation of calyx and corolla
does not exist, the inner thrce Segments of the perianth
are frequently distinctly longer that the outer three, as,
for instance, in Lachenalia and Vropetalum , of the Lily
family, in all the Bromeliacese, Commelyneae, Cannacese,
and Alismacese. The rarer occurrence of petals shorter
tlian the calyx, is explained, in many cases, by an intro-
version of onc formation into the other, whereby the
maximum of longitudinal development becomes displaced.
Th us, in many Ranunculacese [e. g. Trollius , Nigella) the
petaloid calyx is succeeded by shorter and more contracted
petals approximating to the stamens. In other families
also occur isolated genera, with a petaloid calyx, the
leaves of which are longer than the true petals ; e. g. in
Fuchsia (calyx mostly bright-red, rarely white, petals
mostly violct), Bibes ( Chrysobotrya ), Commarum , and
Chmonanthus. The last-named genus has about eight
delicate yellow sepals, followed by an equal number of
dark purple-red petals, only half as long. In other cases
the small size of the petals is connected with a tendency,
prevailing in many families, to suppression of the corolla
(. Sibbaldia , Saginm sp., Paronychia, Gnidia, Santalum,
&c.), to which we shall return hereafter.

No farther increase of length takes place within the
corolla itself, at least I am unacquainted with any instances
of it ; on the other hand, the decrease which succeeds to
the maximum of longitudinal development in the second
member of the flower, not unfrequently commcnces even

REJUVENESCENCE IN NATURE.

79

within the formation of the corolla. Thus in rnost cases
of double or multiple corollas we see the inner circles
formed of shorter and smaller petals. In Fumaria the
inner two petals are only inconsiderably, but in Iiype-
coum considerably shorter than the outer two. Jacquinia
and Achrcis exhibit the same thing in pentamerous and
hexamerous circles. Asimina triloba has a trimerous
calyx, the sepals of which are four lines long. This is
followed by three trimerous circles of petals : those of the
first circle are 7 — 8 lines long, those of the second about
5 lines, and those of the third scarcely more than 2
lines long. The stamens are 1 line long ; the three-lobed
fruit (formed of three carpels) attains a length of 4 — 5
inches when ripe ! The decrease of length of the inner
petals is further shown in all flowers with very numerous
petals, whether they stand in a complex cyclic or in an
acyclic arrangement, as, for instance, in lllicium, Nym-
pliffici* and Mesembryanthemum. f Finally, the graduated
decrease in length in successive petals is very beautifully
exhibited by all “ double” flowers, as they are called, and
most distinctly of all, in those where the doubling arises
merely from formation of petals in the place of stamens (and
offen of carpels also), without the superaddition of axil-
lary sprouts. j The best examples of this kind are found
in the Ranunculacese, especially in Ranunculus, Clematis ,

* Nymplueci alba has about twenty-four petals, the inmost and störtest of
which exhibit a gradual transition into the staminal formation.

t Many species have more than one hundred petals.

+ In the majority of double flowers the “ doubling” is complicated by the
formation of sprouts in the axils of the petals. The sprouts thus appearing
are again imperfect flowers, with undeveloped axes, and mostly formed of
few petals and oecasionally several stamens. Hencc arises an apparently
irregulär accumulation of large and small petals, interposed in various direc-
tions, and often intermixed, with isolatea stamens, of which it cannot be
accnrately determined which organs bclong to the parent flower and which
to the progeny. This occurs frequently, for instance, in double May
flowers, Pinks, Crucifersc, Mallows, and lioses. Howcver, doubling some-
times occurs with and without axillary increase in the samc plant. Some-
times the axillary products of double flowers acquire greatcr completeness,
as is shown most beautifully in the casc not unfrequently occurring in
gardens of Althtea rosea, first observed by G. Engelmann. Vide Engelmann,

‘ De Antholysi,’ t. i, fig. 6. °

80

THE PIIENOMENON OF

Hepatica, Cciltha, and Aquilegia. The Camelliece , the
Campanulacese and Narcissece also exhibit tliis kind of
“ doubling,” and the decreasing length of the petals
connected with it.

With the transition from corolla to stamen-formation
commences a new decrease in length. Far the majority
of plants possessing a highly developcd corolla, agree in
having the staraens, notwithstanding their considerable de-
velopment of st.alk, shorter than the petals. Cases of the
opposite kind, in which the stamens exceed the corolla in
length, are rather rare.* Where two or more successive
circles of stamens exist, there ig often a further degradä-
tion in length, the inner stamens being shorter than the
outer. Tliis is the casc in Narcissus, Muscar i, Daphne,
Myricaria , Boronia and other Rutacese, many Mal-'
pighiaceee and Melastomaceae, lytlirum , Crataegus , &c.
An opposite rclation of length in successive circles of
stamens does however occur, to which we sliall return in
tlie subsequent examination of the subordinate rises and
falls of the metamorphosis.

The third and last inerease in length presents itself in
the fruit, often expressed even at the flowering epocli, by
the projection of the points of the carpcls (styles and
stigmas) beyond the stamens, as universally in the
Campanulacese, Compositse, and Cactacese, bat often first
becoming distinct with the ripening of the fruit.f

Thus the leaf-fonnations exhibit altogether three maxima
in refcrence to length and magnitude, the first falling in
the euphyllary formation, the second in the corolla, the
third in the frnctification. These maxima become some-
what displaced if we regard the leaf in reference to its
inner differentiation, to the more or less distinct develop-
ment of the contrast between stalk- and blade-formation,
and the completeness of the working out of form con-

* Eov example : Ribes staniineum , Fuchsia, Gynoglossum stamineum , llijdro-
phyllum magellanicim, Hyssopus,Vaccinmm stamineum , Erica staminea, carneu ,

-)■ Leguminosffi, CrucifcvsC) (especially the Silir/uosai), Gerau iaccsc, 1 alnue,
&c. See also Asimina triloba, above, pagc 79.

REJUVENESCENCE IN NATURE.

81

nected therewith. In the first region, indeed, the
euphyllary formation exhibits the maximum in this
respect also ; in the flower, on the contrary, it is not the
corolline but the staminal formation which represents the
maximum in relation to internal subdivision, since we
detect in the latter the most distinct Separation of
petiolar and laminar formations. Even vaginal and
stipuloid expansions and appendages now and then occur
at the base of the stamens, still further confirming the
analogy vvith the euphyllary formation. The same
position also denotes the physiological importance of
the staminal leaves ; for euphyllary leaves, staminal
leaves, and carpellary leaves, are evidently the three most
essential leaf-formations, to which the most important
physiological functions are distributed, and without which
a perfect and complete plant is inconceivable,* while
there is a possibility of all the rest being omitted. At
the same time I have hitherto searched in vain through
the Yegetable kingdom for a plant devoid of all the
inessential formations at once, possessing, that is, really
only leaf, stamen, and fructification.

The maxima of the leaf-formation are again differently
distributed when we take the consistence and persistence
of the leaves for a Standard. In the first region the
euphyllary leaves claim the highest place in this respect
also, for although succulent and fleshy cataphyllary leaves
are not rare, the majority of them are soon killed by the
growing warmth of spring, while the euphyllary leaves of
very many plants, fieshily succulent as well as leathery,
are of several years’ duration.f In the flower, the
calyx has the greatest durability, thereby showing a
relation on the one hand to the euphyllary formation,

* Only such plants as do not elaborate their own nutriment, parasites on
living plants and parasite-like vcgctablcs which arc nourished like Fungi 011
decaying remains, can dispeuse with the leaf-formation.

t ßx- gr. in the Cycadcse, Coniferse, Palm®, Aloe, and Agaoe, Crassu-
laceae, Aizoidece, Buxus, Ilex, Citrus, Laurus, and the endless host of ever-
greeu trees of the tropical zones. In the silver fir the duration of the
acicular leaves extends to seven or eight years.

6

82

THE PHENOMENON OE

and on the other to tlie fruit, wliicli relationship is also
particularly confirmed by many abnormal phenomena.
In monstrous affections of the flower, namely, the calyx
on the one side passes very readily into a leafy structure,
and, on the other, often acquires a fruit-like develop-
ment, not only normally, but also in abnormal ways,*
wliile in return the fruit may become calicoid, or even
strike into leafy structure in antholytic flowers. In the
point of view just examined, tlierefore, the euphyUary
formation, calyx, and fruit, form the analogous sections
of the three regions.

The preceding indications may suffice to show that
the leaf-formation by no means exhibits merely a simple
decrease or increase, but, in all respects, a swaying up
and down, a series of vibrations, in the last of wliicli
only is the goal actually attained. These vibrations are
not of equal magnitude or equal force in all plants ; on
the contrary, there occurs, without affecting the general
law, a great multiformity in their conditions. Some-
times the wave expressed in the vigour of the leaf-
formation, rises and sinks slowly and gradually, as we
liave seen in the vegetative region of 'Phlox; sometimes
it gathers itself up abruptly and suddenly, as in 'Epimedium
and Mciyanthemum ; sometimes it ascends suddenly and
sinks down more gradually, as in Pceonia ; sometimes it
ascends contrariwise, gradually, and sinks down again
more suddenly, as in Ileliconia. The transition from
one region of ascent to another is marked sometimes by
a slight, sometimes by a strong depression. This differ-
ence is especially manifested in the transition into the
flower, since on the one hand there is not unfrequently a
direct passage from the euphyllary formation into calicine
formation, (almost devoid of any retrogression in the
leaf-formation, and with total omission of the hypso-
phyllary formation especially representing the descending

* I have observed tliis in especial beauty in a malformation of Citrus
medica, where the calyx formed as it were an open citron snrrounding the
inner natural fruit.

RU JUVENESCENCE IN NATURE.

83

side of the first region,) as in Gentiana ;* while, on tlie
other liand, tlie leaf-formation often sinks down before
the transition into flower, to complete disappearance of
the leaf, which as it were emerges anew in the
flower. Within the general lines of rise and fall, even,
occur other subordinate lines of undulation, correspond-
ing to the individual formations, which will be briefly
touched upon hereafter. Every plant has its proper vital
lines for these vibrations of the metamorphosis, the
constractive representation of which lines will make
clearly conceivable, characters which botanists have
hitherto only seized in the most fragmentary manner, or
have feit obscurely as something inclescribable in the habit.

A particularly important phenomenon belonging to
this series is the occurrence, at determinate points of
transition of the metamorphosis, of the above-mentioned
disappearance or non-appearance of leaves which exist in
rudiment, but either clo not come to full development, or
are suppressed in the earliest stagesof formation.f This
dipping down of the leaf-formation, occurring so frequently,
and connected with determinate regions, \ is the best evi-
dence of the undulating course of the metamorphosis, and
the best criterion for the separate sections. Disappearance
of this kind occurs at four different places in the process
of the metamorphosis, namely, first at the two points of
depression, already considerecl above, at the points of
transition of the three cliief regions one into another,
from stock to flower and from flower to fruit ; and at two

* See especially G. campestris , in which the first two sepals are com-
pletely foliaceous,

t Tliis phenomenon belongs to what botanists call abortus, against the
multifold groundless and superficial assumptions of which Schleiden very
justly inveighs repeatedly, (‘ Grundzüge,’ ii, 188.) The correct application
of tlie comparative metliod will guard us from such idle speculation, and
indicatc to us with certainty suppression of leaf-formation, even in cases
where observation of the course of development is perluips never capable
ot atfording a demonstration.

.+ Another series of abortions, here left enlirely out of view, is conuected
with the zygomorphic and antagonistic structure ofwhat are callcd irregulär
nowers.

84

THE PHENOMENON OF

otlier, subordinate points of descent which have still to
be examined more narrowly, at the transition of the
euphyllary formation unto tlie hypsophyllary formation
and of the corolla (or calyx) into tlie staminal. formation.
In order to represent tlie occurrence of regions of vanishing
in tlieir relation to tlie entire graduated series, we will
once more review tlie series, in tlie order of tlie tran-
sition of the metamorpliosis from formation to formation.

Within tlie catapliyllary formation we liave observed
an increase of strength in the leaf-formation, which is
continued without any preparatory decrease into the
euphyllary formation. The leaf-formation runs progres-
sive^ from the catapliyllary formation to the euphyllary
formation citlier without any, or witli imperceptible descent
at the point of transition, consequently no vanishing ever
occurs between these two formations. I sliall not venture
to decide whether tliis transition takes place really without
any descent, or sometimes, perhaps, has connected with
it a slight decrease in the leaf-formation. The latter
hypothesis seems to be bornc out by Adonis vernalis. I
found the 7 or 8 catapliyllary leaves of tliis plant of
gradually increasing lengtli, growing from 1 to 8 lines ; a
transitionary leaf following them, and exhibiting the first
trace of blade-structure at its apex, was somewhat shorter
than the last true catapliyllary leaf, namely, only about 7
lines long.

In the euphyllary formation we see the attainment of
the maximum of vegetative leaf-formation followed by a
decrease, which is frequently continued into the hypso-
phyllary formation without any new accession of strength.
13 ut the case is not always such ; the transition of the
euphyllary formation into the hypsophyllary formation is
often effected through the medium of a strongish retro-
gression, which may go as far as disappearance, whereby
then the hypsophyllary formation is cut off as a distinct
wave, since it then possesses its own special rise and fall.
The hypsophyllary region, cut off in tliis way, thus forms
within the vegetative sphere a prototype ol the flower,

REJUVENESCENCE IN NATURE.

85

which affords a certain justification of the old application
of the name “compound flower,” to the capitule of the
Compositse and the spikelet of the Grasses. If we examine
the order of capitulons-flowered plants (Compositse) in
reference to this point, we find hypsophyllary forma-
tion but seldom exhibiting a mere decreasing condition
of the leaf-formation, for the involucres or “common
calices” are mostly formed of hypsophyllary leaves larger
than those immediately preceding them on the stalk,*
and within the involucre itself there mostly occurs a
further increase of size of the successive involucral-leaves,
as is shown in the so-familiar “ involucra calyculata ”
and “ imbricata.”f This phenomenon is truly splendidly
exhibited in the coloured, radiantly expanded involucres
of Carlina, Xeranthemum, and Helichrysum. In the
last-named genus (e.y. in II. proltferum), we even find
the rare case of hypsophyllary formation far exceeding in
its ascent the size of the euphyllary leaves. After the
maximum is attained the hypsophyllary formation sinks
down again, upon the main axis, to the form of little
paJem or teeth, often passing into a fibrous dissolution,
frequently at last vanishing altogether, ( receptaculum
jpaleaceum, denticulatum, ßbrillosum , nudum .) I will
describe somewhat minutely in this respect Calliopsis
bicolor, an ornamental plant generally difiused in gardens,
as an example. Cataphyllary leaves are absent. We find
the leaf-formation advancing, on the abbreviated base of
the stock, from simple to simply pinnatifid and bipinna-
tifid euphyllary leaves. On the ascending part of the
stem follows a decreasing series of small-lobed bipinna-
tifid, simply pinnatifid, and at last simple euphyllary
leaves, which form the transition to a few very small
linear, brownish-coloured hypsophyllary leaves scattered
on the stalk of the capitule. The 8 outer leaves of the
involucre are already somewhat larger, especially broader,

* See, for instance, Hieracium subaudum and allied spccies, Leontodon
squamosus, Catananche cacruleu.

t Ex. rjr . Chrysanthemum Leucanthamum, Taraxacum, Scorzonera , Cynara.

86

THE PHENOMENON OF

than the preceding scattered hypsophyllary leaves ; the
8 inner involucral leaves, in the axils of which are seated
the 8 florets of the ray, are 5 — 6 times as long and broad
as the outer, lighter colonred, and raore scarious. This
constitutes the maximum of the hypsophyllary formation ;
the succeeding bracts (palese) are shorter, almost filiform,
and transparent, with a thin brown central streak. Another
example, which exhibits not only a sinking and reascent,
but an actual disappearance, at the transition from the
euphyllary to the hypsophyllary formation, is afforded by
Thnilia sagittata ( Cacalia sonchifolia of gardens.) The
large euphyllary leaves embracing the stem with their
arrow- or heart-shaped bases, are followed by a narrovv
linear transitional leaf, from the axil of which arises the
first branch of the corymbose inflorescence. From 2 to 4
leaves are thus wholly suppressed, their existence being
merely detected by the branches of inflorescence being
apparently devoid of subtending leaves. rFhe leaf-
formation rises up again in the involucre of the ter-
minal capitule, composed of 13 equally long, linear
hypsophyllary leaves, and generally vanishes again on
the “ receptaculum nudum .” A similar disappearance
and re-advance of the hypsophyllary formation, only
distributed on distinct axes, is seen in those Umbelliferae
which are devoid of an involucre, but have au involucel,
as for instance in Angelica sglvestris, iSeseli montanum
and Hippom arathrum, and Bupleurum rotundifolium.
The leaves of the involucels are at the same time the
bracts (subtending leaves) of the outermost flowers of the
umbellule, while the subsequent, more internally situated
flowers, arise from the axils of suppressed leaves. Thus,
the Bupleurum mentioned has only five involucellar
leaves, but eight to thirteen flowers in each umbellule,
the central flower not included ; therefore three to eight
flowers must spring from the axils of invisible leaves. A
third large order, in which the hypsophyllary formation
occurs in similar conditions, is that of the Grasses. Here
it is universal for the euphyllary formation to be followed

ltEJ UVENESCENCE IN NATUltE.

87

immediately by a suppression of the leaf-formation, which
persists through the whole main superstructure of the
inflorescence, and only ceases in the spikelets. The leaves
often disappear entirely in this region, or they present
themselves as more or less evident thickenings, some-
times completely embracing the stem as rings,* * * § and then
often curved up and down in wravy lines, sometiraes only
partially embracing, and then mostly with decurrent
borders,f rarely ascending on the axis.J In Elymus
europceus the lowest annular abortive leaf is often elon-
gated into a sliarp tooth ; in Nardus all the subtending
leaves of the spikelets are tooth-like. Only few grasses
exhibit a considerable development of the lower leaves on
the axis of the inflorescence, such as occurs in Sesleria.
In Sesleria ccerulea they present themselves as tubulär,
ochraceously-truncated, or irregularly excised, mem-
branous sheaths.§ A similar development of the first
leaf of the inflorescence occurs not unfrequently as an
accident and exceptionally, in other grasses. I have
observed a stränge form of this phenomenon, and this
frequently, in Glyceria aquatica. The transitional leaf
occurring here, in the axil of which Stands the first so-
called semi-verticil of the panicle, has an undeveloped

* Thus, for iustance, the lowest abortive leaf of Triticum , Secale, Oryza,
&c., wliile the succeeding do not embrace ; in Glyceria fluitans and aquatica
several of the lower abortive leaves are annular.

t Especially fine in Melica altissima and Phalaris arundinacea. Very
beautifully so in the lower abortive leaves of Loliuni, Poa compressa,
Cynosurus, and Dactylis. The obliquely descending borders are even con-
fluent on the lowermost. The overlooking of these abortive leaves led to
the error of regarding the glume of the spikelet of Lolium as its subtending
leaf. This mistake might be pardoned in a superficial exainination, but it is
incomprehensible how any one could see the true condition clearly, and even
draw it, and yet retain the false explanation, as Turpin has done. See his
plate of Lolium pcrenne in the ‘Dict. des Sc. Nat.,’ and the explanation
given of the figurcs.

% Thus, for example, the lowest and not always distinguishable abortive
leaf of Alopccurus ayrestis.

§ These ochraceous leaves are followed by one or the other unilaterally
developed bract; at the base of the uppermost lateral spikelet, on the
cont.rary, they vanish entirely, as in other grasses. In Oreochlna they are
not so strongly developed, and only the lowest are one-sided. See on this
point also Röper, ‘ Zur Flora Meklenburgs,’ ii, 42.

88

TUE PI1EN0MEN0N OE

middle, simply a protuberance, while thc lateral portions
growing together on the side opposite to the middle,
acquire very considerable development. Hence arises an
appearance as though the subtending leaf stood opposite
totliebranch. It often attains a considerable size and a
more or less foliaceous expansion, exhibiting a distinction
into stalk and blade. The sheatli usually reaches alength
of li to 2 inches ; the blade seated npon tliis, about of
equal length, is double, on account of the absence of the
middle, the tvvo halves diverging at an obtuse angle.
Among the grasses in which the disappearance of the
leaves in the inflorescence is most complete, so that even
the lowermost often does not even leave a protuberant
process, arc Catcipodium , many spccies of Eragrostis ,
Eleusine, Digitaria , and Sorghum. In thc spikelets,
finally, the leaf-formation comes to light again, frequently
gradually, as in Orgza * * * § and all other grasses in which
the first glmne is very small ( Vulpici , Airocldoa, Anthox-
anilium ) ; frequently suddenly, as in all grasses with two
large glumes (llolcus, Phalaris ). Most of the many-
Jlowered grasses exhibit, further, a distinct increase and
falling off in the successive hypsophyllary leaves of the
spikelet, sincc the first sterile palese are shorter than the
sueceeding fertile ones, which tliemselves again decrease
in size towards the point of the spikelet.f lt is rarer for
the first palese to be the largest, so that a simply decreasing
condition exists.J The reverse, a merely ascending con-
dition of the palese of the spikelet, is exhibited by many
one-ffowered grasses, in particular the already citecl Rice,
and most of the genera allied to Panicum .§

* In Oryza thc spikelet begins with four sterile palcac, followed by only
one fertile. The first two or three sterile pale® appear only as small teeth.
Teersia is distinguished from Oryza merely through thc still more imperfect
development of the first four palese of the spikelet.

j Thus, for instance, in Bromus, Fcslaca, Boa, Dactylis, Secale, Melica,
Molinia, Phragmiles, Chloris.

1 Thus in Triodia , Agrostis, Calamagrostis.

§ A decrease may takc place in these in an abnormal manner, wlien,
namely, the axis or rachis of the spikelet develops additional paleie (and
flowers in their axils). An intcresting case ol tliis kind occurs almost

REJUVENESCENCE IN NATURE.

89

From the vanishing region at thc entrance of the
hypsophyllary formation, wbere this separates as inde-
pendent, we coine to the consideration of tliat transition
in which the disappearance of the leaf-formation is com-
monest, to the transition from the hypsophyllary formation
to the floioer. Here where the most important revolution
occurs in the metamorphosis, where the leaf-formation is
to return in new arrangement and altered attire, there is
most frequently a preparatory total contraction, so that
the region of transition into the flower must be desig-
nated as the principal break in the metamorphosis. The
disappearance of the leaf-formation occurring here may
extend simply to a last organ, or over the entire hypso-
phyllary formation ; in fact, it may even invade the outer
formations of the flower. Of the first case, in whicli only
a final section of the hypsophyllary formation undergoes
Suppression, we have already seen above a fine example
in the Compositse with naked receptacles succeeding a
fully-developed involucre; and in the Umbelliferse with
umbellules, the outer rays of which arise in the axils of
involucellar leaves, while the inner possess no visible
bracts. Such cases are more uncommon on racemose or
spicate inflorescences with elongated axes, but Castanea
and Acalypha may be mentioned, the spikes of which
have perfectly developed hypsophyllary leaves at the lower
part, bearing the female flowers in their axils, while the
male flowers succeeding upward arise from the axils of
abortive leaves. Here refer also the Aroidese, which
possess a large, often petaloid, coloured hypsophyllary
leaf at the base of the spadix, while no further visibly
developed leaves occur upon the spadix. Suppression of
the last hypsophyllary leaves is more commonly found
when these are situated on a second axial System, than

nomnally in a Panicim cultivated in gardens, which I have named P. ( Echino -
chloa) mirabile. This species, allied to P. stagninum, very frequently presents,
besides the three ordinary glumes and the normal palea ( deck-spelze ) enclos-
mg the flower, a second smaller palea, which, likc the first, conceals a
perfect flower in its axil.

90

THE PHENOMENON OF

when on the same axis. Tims it is a very common
phenomenon for the axis of racemose inflorescences to
have developed hypsophyllary leaves (bracts), while those
on the flower-stalks {vorblätter, bracteoles) are snppressed.
Numerous examples of this are furnished by the Scrophu-
larineae,* * * § Verbenaceae,^ Labiat9e,;|; Leguminosae,§ and
also Fumaria and Corydalis, Iiedera Helix , Mahonia,
Thesium ebracteatum and rostratum. || The other case,
in which the entire hypsophyllary formation is composed
of abortive leaves, is likewise very common, we find it in
almost the whole family of Cruciferse, in Convallaria
multißora , of which, besides, there is a variety with de-
veloped and even foliaceous bracts ; in many Legumin osse,
e. y. Trifolium , in the Umbelliferae without involucre and
involucel, e.y. Anethum and Foeniculum. Great numbers of
examples might be cited of plants with terminal flowers,
where conseqnently the leaf-formation reappears again on
the same axis, in the flower, after the suppression of
several leaves, e.y. Solanum , GUiairicolor, capitata , many

* Ex. ffr. Digitalis, Aniirrhinum, many species of Linaria, Verbascum
Blattaria , while in Verbascum Thapsus , and the allicd species, as also in
Scrophularia , Gratiola , &c., the bracteoles are developed.

,f Verbena , Aloysia, while Vitcx exhibits developed bracteoles.

% Teucrium , Prunella; in many other genera of the family the bracteoles
are visible. Scutellaria exhibits a bcautil'ul transition to the suppression of
the bracteoles, for in many species, for instance S. alpina , they exist only
as scarcely perceptiblc papillm. Salvia presents a series very instructive in
this rcspect. S. patens and dulcis have solitary flowers stauding in the
axils of oracts, without visible bracteoles ; S. coccinea , splendens, and involu-
crata, have thrcc-flowered, S.farinosa ( trichostyla , Bisch off), and confertiflora
many-flowered cymes without visible bracteoles ; S. Horminum three-flowered
cymes with developed bracteoles of the middle flowers, but not of the
lateral flowers ; S. fflutinosa , lastly, has three-flowered cymes with developed
bracteoles of both the middle flowers and the lateral flowers.

§ Pisurn, Galega, Podalyria australis; 'mColutea and Lwpinus the extremely
small bracteoles at the base of the calyx are offen scarcely visible ; in other
genera, P/iaseolus in particular, they are more considerably developed.

|| 1 have purposely cliosen only such examples as at once sliow the exist-
enee of the supposed“ bracteoles, either by the visible presence of these in
other genera of the same family, or even other species of the samegenus,
leaving out ofthe question other grouuds for the assumption. ln the
family of the Bumariacese they are visible in Dielytra; in the Bcrbcridesc in
Berberis itsclf ; in the genus Hedem in H. capitata ; in the genus Thesium in
all the other indigenous species except the two mentioned abovo.

REJUVENESCENCE IN NATURE.

91

Boraginese ( Myosotis , Omphalodes linifolia), most of tlie
Hydrophylleae ( Phacelia , Hydrophyllum canadense ), Cistus
salviatfolius and monspeliensis, Ulmaria palustris, &c.

The suppression of the leaf-formation at the transition
into the flower may affect, as above remarked, not merely
the last section of the leaves preceding the flower, but
even the commencing formations of the flower itself. Thus
we see the calyx, at least its free portion, undevelopecl or
appearing as a crown of hairs in the Compositae, many
Umbelliferse, Rubiaceae, and Valerianese, whilethe corolla
is developed fully in these families. Calyx and corolla
are suppressed together in Fraxinus, while the n early
related genus Ornus exhibits both; the same occurs in
many Amentacese, especially of the group of Betulaceae.*
The perigone of the Monocotyledons is suppressed in
many Aroidese, e.g. in Calla, while it is visible in Pot kos
and Acorusj in the Cyperacese, also, where it frequently
presents itself in the form of bristles, which may be com-
pared to the pappus in the Compositse ;f and, finally, in
the Grasses, in which, however, the inner circle of the
perigone, analogous to the corolla, comes to light, wholly
or partly, in the form of little scales {lodiculce) 4

* In Ainus and Betula the calyx is indistinguishable in the female flower,
but visible in the male ; in Carpinus and Corylus, on the other hand, the male
flower is devoid of a visible calyx while the female possesses one.

f The three scales in the flower of Fuirena do not belong to the perigone,
but correspond, as Nees eorrectly assumes, to the inner circle of stamens.
They stand decidedly inside and not outside the three fully-developed stamens.
See, for other points, the in other respects accurate description ofthe flower
of the Fuirena ?, by Schlechtendal, (‘Bot. Zeit.,’ 1845, p. 849.)

+ The inner perigonial circle is perfect, composed of three little scales, in
Slipa and the Bambusece; in most of the other grasses it is imperfect, the
leaf falling postcriorly being suppressed. Sometimes the abortion extends to
the inner circle of the perigone, as in Crypsis, Alopecurus. As regards the
foundation for the assumption of an outer, constantly abortive perigonial
circle, it can only be observed here that it is derived i’rom the comparative
study of the rudiments of the branches of the monocotyledons and the rulcs
of insertion of lateral flowcrs dependent thereon. Ünder the hypothesis
that it possesses a double perigone, the flower of the Grasses Stands in the
axil of its bract exactly like the bracteolate flower of the Iridcoe. The same
attachment of the flower is probably to be assumed of the Cyperacese also,
only in this family the bracteole (the inner palea) is constantly suppressed,
while in the Grasses it is fully developed, except in a few cases ( Trickodium ,
Alopecurus).

92

THE PHENOMENON OF

We now come to the transitions within the flower
itself. The transition from the calyx to the corolla cor-
responds to that from the cataphyllary to the euphyllary
formation, and takes place like this, without any, or with
an insignificant retrogression of the leaf-formation, on
which account no suppression occurs between these two
formations. We have above seen, in many cases, an
increase of the leaf-formation within the calyx, and re-
cognised in this the expression of the renewed impulse
received in the first half of the flower ; the contrary case,
a decrease of size following the order of succession of the
scpals, expressing an indentation in the line of impulse
ascending to the corolla, is a rare phenomenon, and is
only represented by faint indications. Thus in the
Gentiana, Gerania, Nicotiana, evcn in the Böses and
Bramhles , the inner sepals are somewhat shorter than the
outcr. Of all cases of this kind, the calyx of Acanthus
exhibits the most striking character, which, however,
from the irregularity of the whole flower, cannot be
explained simply in this way. It is composed of four
pieces, an upper, broadest and longest (the second sepal);
a lower, somewhat narrower and shorter, which has two
points (it is formed from the confiuence of the first and
third sepals) ; finally, two lateral, which stand further
invvards, and are much shorter than the upper and lower
pieces.* These little lateral sepals are the fourth and
fifth, consequcntly the last two leaves of the calyx. The
calyx is preceded by two very narrow linear bracteoles,
which are about half as long as the calyx ; a broader and
longer bract, having sharply-toothed borders, bears the
flower in its axil. Here, therefore, we see a desccnt from
the bract to the bracteoles, an ascent from the two
bracteoles to the outer sepals, and another descent from
these to the two inner, and finally, from these to the
corolla a fresh ascent of the leaf-formation.

That which is found only in rare and faint indications

* The two lateral pieces are to 2 liues long, the lower about 15 lines,
the upper 17 lines.

REJUVENESCENCE IN NATURE.

93

in the transition from calyx to corolla, is a very frequent
phenomenon in the transition from the corolla to the
stamen-formation. As the hypsophyllary formation is
not unfrequently cut off from the euphyllary region by
sinking down even to the Suppression of the leaf-forma-
tion, so we see the stamen-formation frequently cut off
similarly by a region of suppression, from the preceding
formation. It is often difficult to decide here whether
the parts subject to abortion, which may occupy one or
more circles, are to be regarded as suppressed inner
petals or suppressed stamens. As imperfectly developed
leaves, they are, looked at by themselves, neither one nor
the other ; but comparative examination shows that the
abortive circles are certainly to be attributed sometimes
to one and sometimes to the other side, and in this sense
are to be regarded sometimes as inner circles of the
corolla, and sometimes as outer circles of stamens. Thus
in the Primulaceae for example, we liave reason to con-
sider the abortive circle as an inner corolline circle, since
the corresponding circle of the flower is developed in
some of the genera of the allied family of the Myrsineae
{e.(/., Jacquinia ), as also in many of the genera of the
likewise related Sapoteae, actually in the form of an
inner corolla, never in the form of a circle of stamens.
The same holds of the Ericaceae, in which I have seen
the abortive circle developed abnormally, in Erica
haccans, as an inner corolla. The same occurs in the
Jasmineae, for some of the species of jasmine exhibit
an inner corolla almost normally. In the Oxalideae and
Geraniaceae we must also assume an abortive inner
corolla, the traces of which exist in the form of glands or
little scales. In abnormal flowers of Pdargonium, I have
often found some of the organs actually developed into
the form of petals. That the abortive circle of the
Geraniaceae is to be regarded as an inner corolla, is still
more distinctly proved by the mode of arrangement of
the parts of the flower in the gcnus Monsonia, belonging
to this order. Monsonia possesses not merely two, but

94

THE PHENOMENON OF

three quinate circles of stamens, wliich tliough t prosen-
thesis are placed in a ternary relation of alternation, while
the abortive circle still belongs to tlie binary condition of
alternation (tliough i prosenthesis). In the Orassulaceae
likewise, the abortive circle may be regarded as an inner
corolla, although the arguments for this ave less direct.
On the contrary, the abortive circle is in some cases
decidedly an outer circle of stamens, for instance, among
the Monocotyledons, in the Burmann iaceae and Ponte-
deracem, among the Dicotyledons, in many Malvaceae
and Tiliaceae, e.g-, Ilelicteres, Hermannia, moreover in
the Ampelideae and Rhamneae. Both united, i. e.,
two abortive circles, a suppressed inner corolla and a
suppressed outer circle of stamens, at the sarne time,
occur in the Crassulaceae wliich have only one circle of
stamens properly dcveloped, as for instance Crassula
and Tillaa ; likewise in Erodium, of the family of the
Geraniaceae, and the allied Linum; in Blaria and
Azaleci , of the heath family.* As we have seen in the
conditions of the transition to the flower, examined above,
that the tvliole of the preceding hypsophyllary formation
frequently vanishes, so this is repeated here. Not
merely particular Segments, but even the entire corolla
may vanish. We have already seen an approximation to
this in the exceptional cases, in wliich the maximum of
the leaf- formation witliin the flower is not attained in
the corolla, but already in the calyx, while the petals
appear small and imperfect.t The apetalous flowers
produced in this way occur in very many families,| and
allow their true nature to be readily decided when we

* In tliis and similar cases no circle seems to be absent, since when two
succeediug circles are suppressed, the alternation of the properly developed
circle is restored.

t See pages 78, 79.

% To prevent misunderstaudings, I must remark that the condition of
abortion is not the explanation of all apetalous flowers. Tkcrc are families
in wliich the metainorphosis actually progresses directly from the calyx-
formation to the stamen-formation, without auy suppressed intermediate
formation corresponding to the corolla ; thus, for instance, in the Polygonese
and Laurinese.

REJUVENESCENCE IN NATURE.

95

accurately make out the conditions of relationship. Tlius,
for example, the genus Glaux agrees so closely with the
type of the very sharply-defined Primulacese, that we
liave 110 hesitation in ascribing the apetalous condition of
this genus to the suppression of two circles of petals.
The Chenopodiaceae, Amarantaceas, and Scleranthese, are
connected so unmistakeably with the petaliferous families
of the Order of the Caryophyllaceae, particularly with the
Alsinece, that we at once regard them as Apetalae pro-
duced by the suppression of the corolla, especially when
we take into consideration how such a suppression occurs
in particular cases among the Silenece and Alsinece , and
may even be demonstrated in one and the same species,
sometimes in all gradations, as for instance, in Stellaria
media, which is found with very different sizes of the
petals down to complete abortion of them (var. apetala).
The conditions are similar in the apetalous state of
Peplis among the Lythrarieae, Isnardict among the
Onagreee, Chrysosplenium among the Saxifrageae, Sterculia
among the Tiliaceae, and Pistacia among the Terebin-
thaceae. In Pliytolacca decandrci, the quinate corolla
vanishes together with a ten-membered outer circle of
stamens, which latter exists perfectly developed in P/i.
icosandra.

I will only add, to these already too widely extended
remarks on the subordinate retrogression of the leaf-
formation which is frequently interposed at the tran-
sition to the stamen-formation, and which causes an
independent Separation and uplifting of this most im-
portant section of the flower, that the ascending condition
in the succession of stamens or of circles of stamens,
mentioned above as an apparent exception,* is explained
by this, corresponding exactly to the rise in the magni-
tude of the hypsophyllary leaves, which we have already
examined.f This phenomcnon is met with, for example,
in Aloe, Anthericum,, Ornithoyalum, in which the three

* See page 80.

f See page 85.

96

THE PHENOMENON OF

inner stamens are longer than the three outer, also in
the Cruciferae, in the well-known tetradynamous con-
dition ; in Asarum, with six outer shorter, and six inner
longer stamens ; in Hheum, with six outer shorter, and
three inner longer ; in Oxalis and Limnanthes, with five
outer shorter, and five inner longer ; in Monsonia , with
ten outer shorter, and five inner longer; lastly, most
beautifully in Hibiscus and other Malvacese, in wliich
numerous quinate circles of stamens are piled up into a
more or less abundantly clothed colurnn. Most of the
Ranunculaceae, in particular Anemone decidedly, exhibit
a gradual increase of lcngth of the stamens, together
with an acyclical, spiral arrangement of them ; and many
of them a decrease again at the close of the formation,
as in Pcconia Montan , the innermost, shortened, and
abortive staminal leaves of wliich, form by their con-
fluence the well-known crimson crown round the germen,
which Dccandolle considcred as one of the principal
Supports of his tlieory of the torus.*

The structure of the Chinese Pcony just noticed, leads
us to the examination of the transition from the stainen-
formation to the fruit, the last chasm which the plant
has to pass over in its path to the goal. In this transition
to the last stage of the metamorphosis, a complcte Sup-
pression of the leaf-formation occurs far more frcquently
than at the transition from the corolla to the stamen-
formation, a circumstance of especial importance for a
correct insight into the structure of most flowers. In the
Monocotyledons only, in which in general the formations
are less sharply separated, a direct transition, uninter-
rupted by Intermediate abortive circles, is the more
frequent condition, while in the Dicotyledons this occurs
as the rule only in few families, particularly such as
exhibit affinity to the Monocotyledons in other respects ;
in many others not at all, or only in isolated genera.
This also furnishes the explanation of the rarity of

* Decandolle, ‘ Organograpkie,’ i, 184.

REJUVKNESCENCE IN NATURE.

97

abnormal transitions between these two formations, a
transformation* of stamens into carpels, or, retrogres-
sivelv, of carpels into stamens, f while the transitions
between calyx and corolla, as well as between petal- and
stamen-formation are comparatively far more frequent.
The abortive circles must here be accounted partly to
one and partly to the other of the formations adjoining,
the altered conditions of arrangement and number so
frequently occurring in the fruit affording a distinct Sup-
port for this in many cases. The abortion of an inner
circle of stamens is exhibited most convincingly by many
species of Junens , which occur sometimes hexandrous and

* I use this term in the sense explained above, pp. 60, 61.

f The occurrence of such transitions is in most cases a certain indication
that no abortive circle exists, but the cases must be closely examined, in
order that a mere multiplication of the Organs of one or other formation,
such as may happen through an alteration of relative position or through
axillary formations, may not be taken for a substitutive aberration of
structure. Consulting the sections on the transformation of pistils into
stamens, (218), and stamens into pistils, (220), in Moquin Tandons
‘Teratologie,’ we lind that after separating the doubtful from the trust-
worthy and accurately lcnown cases, the examples mentioned beloug to
three families of the Monocotyledons, (the Liliaceaj, Colchicacem, and Palmae),
and eight families of Dicotyledons, (the Ranunculacese, Magnoliacem, Papa-
veraceae, Cruciferae, Crassulaceae, Ericacese, and Primulaceae). I havemyself
observed most of these, as well as many other less known cases. To the
latter belong, for instance, the transformation of the carpels into stamens in
Allium Schanoprasum, which seems to occur as commonly in the chives
cultivated in gardens, as the opposite case of the inner stamens t urning into
carpels in the cultivated Sempervivum tectorum. This transformation is
exhibited in the cliive in the most varied degrees ; it is further remarkable
from the fact that the stamens appearing in the place of the three carpels,
have extrorse anthers, while the anthers of the six normal stamens are
introrse, a condition which reminds us of the similar double character of the
anthers in the Laurinese and Polygoneae. Strange too, is the occurrence of
three more shorter stamens, which are confluent with the three replacing the
carpels, and which 1 can only regard as axillary structures like those
occurring in double flowers, (see note, p. 79.) In this case we find inside
the decomposed germen, which lias passed over into a staminal formation, a
new more or less perfectly developed whorl, the organs of which alternate
witli those of the prececling whorl. Another case, apparently also little
known, but equally frequent, occurs in the cultivated horse-radish ( Armoracia
ruslicana). The two carpels are here transformed more or less completely
into stamens, while two other organs, absent in normal flowers, make their
appearancc as carpels. The reverse case, the transformation of all the
stamens into carpels, is showu by Cheiranlhus Cheiri gynantherus , Dec., a
monster which has become a variety in the Paris garden, and for which I
am indebted to M. Gay.

7

98

THE PHENOMENON OF

sometimes triandrous,* also by tlie Irideae, Graminaceae
and Cyperacese,t Alisma and Actinocarpus,% Cerastium
semidecandrum , and tetrandrim , Mcenchia quaternella ,
the tetrandrous species of Sagina, the pentagynous
Campanulaceae, e. g., Camp anul a Medium, \ Drosera, ||
Tamarix*^ Viola, &c. On the otlier hand, an outer
circle of stamens is abortive in Triglochin palusire, while
in Tr. maritimum both circles are fully developed ; in
most of the digynous Solanaceae {i. e., with two carpels),
in like mann er, while in Nicotiana quadrivalvis the fruit
becomes four-chambered, by the development of both
circles; moreover, in most of the Gentianeae and
Apocynem, the Scroplmlarineae and Labiatae, the genera
of Rutaceae with a double circle of stamens, the digynous
and trigynous Alsinece and Sileneee, as well as the penta-
gynous genera Malachium and Agrostemma .**

An inner circle of stamens vanishes, together with an
outer circle of carpels, for instance, in Slettaria media
( pentandra ), in most of the Diosmeae, Cneorum, Celas-
trineae, Ludioigia, and Isnardia, Circcea (?),f f Ilederaceae,
Umbelliferae, &c. It is probable that in the Polygoneae
tliere is a suppression of li to 2 circles of stamens, and
one circle of carpels. In Rosaceae, Pomaceae, Amygda-
lineae, Myrtaceae, and Philadelphus, there is certainly
a suppression of several circles of stamens at the transition
to the fruit ; probably also we ouglit to assume two abor-
tive circles between the stamen-formation and the fruit
in the flowers of the Papilionaceae. A glance back over

* Juncus supitius is ordinarily triandrous, the variety whicli is lield as
J. nigritellus , I)on, is hexandrous.

• • At least in the Cyperinai, the Caricince may be different ; see below.

; : Alisma and Aäinocarpus are rudimentarily enneandrous, like Butomus.

j The suppresscd circle of stamens appcars developed in the double
Campanula Medium of gardens. In this case the first circle of stamens
becomes the inner corolla, the abortive circle the circle of stamens. The
form and arrangement of the carpels remain unchanged.

|[ Both circles are developed in Brosopliyllum.

«[ In Myricaria ( Tamarix germanica, L.) both circles are developed.

** See the ‘Flora,’ 1843, No. XXII, et seq.

ft See the ‘Flora,’ 1835, I, 179.

R E J U YEN ESCEN CE IN NATURE.

90

the examples previously mentioned of the occurrence of
abortive circles at the passage from calyx and corolla to
stamen-formation, taken in compärison with the instances
just brought forward, of abortion of leaf-förmations at
the transition to the fruit, leads to our reraarking that
they are almost throughout derived from different natural
families, which gives rise the observation, that a Suppres-
sion at both the said points of transition at once is among
the less frequent cases. Tlius abortion occurs merely at
the first point in the Primulaeeae, Geraniacese, and
Malvaceae, solely at the second place in the Rutacese,
Onagreae, Solanaceae, &c. Cases whete it is met with
in both regions are furnished by the apetalous Caryo-
phyllaceae, e. g. Stellaria media apetala, Scleranthus ;
also by the apetalous Leguminosae and Rosaceae, but
most convincingly in Limnanthes. This genus exhibits
five sepals, and five perfect petals alternating with thcse ;
next, also alternating, five glandular scales, the traces of
an abortive inner corolla ; these are succeeded by two
pentamerous circles of stamens, the outer of which, lying
opposite the petals, are shorter, the inner, opposite the
sepals, larger ; finally, five carpels, which are opposite
the inner stamens, and therefore lead to the suppositiori
of the abortion of one circle.

In many plants, intermediate structures occur in the
Position of the abortive circles, between flower and fruit,
softening the abruptness of the passage from the acute and
transitory stamen-formation to the calm and enduring
structure of the carpel. In many cases these transitional
structures are but stunted, as, for example, in the circle
of glands which succeeds the three circles of stamens in
the flower of the cinnamon tree ; very often they are more
developed, as in the two circles of lanceolate, sinüäte-
bordered leaflets inside the staminal circles of Jquilegia,
and the above-mentioned structure of Paonia Montan.
It is remarkable that these transitional structures soine-
times assume completely the shape of an inner corolla.
We have already noted above the affinity of the calyx

100

THE PHENOMENON OF

to the fruit ; so , just as in the ascent from calyx- to
stamen-formation, the corolla lies between the two, we
again find the petal formation, as a pengynium , in the
descent from the stamen -formation to the fruit-formation.
In many Limes the similarity between the perigynium
and the eorolla is perfect, while in other species of the
same genus normally developed stamens occupy its place.
The resemblance to petals is less marked in the peri-
gynium of the Byttneriacese and Dombeyacese ; in the
Malvaceae, especially distinctly in Hibiscus, it forms
the inside of the tube, from the outside of which the
circles of stamens pass off at various heights.

Lastly, we have still to consider the cases in which, at
the last stage of transition of the metamorphosis, the
suppression acquires such extent, that the entire stamen-
formation becomes involved, or, on the reverse, this exists,
and the fruit-formation is suppressed. The neccssity
of fliese two formations to propagation, makes it a con-
dition that, in such cases, the plant bears two kinds of
flowers, — staminate (male) and pistillate (female) flowers,
United on the same “ stock,” or distributed on distinct
“ Stocks.” Examples of this kind occur not raerely
scattered singly in the most diverse families, but there
are even entire families in which this condition appears as
the rule. To the former belong dioecious species of the
genera Lychnis, Silene, Rhamnus , Rumex, the genus
Rliodiola of the family of Crassulaceae, the genera Smilax
and Ruscus, of the alliance of Lilieae, and Zea and Coix
among the Grasses ; to the latter belong the Palmae and
Cucurbitaceae. In all these the male and female flowers
have the same type, but differ in the completion, since
the plant is incapable of combining the contrast of stamen-
and fruit-formation within the ideally limited space of one
flower. In the male flower the leaf- formation sinks down
after bringing forth the stamens, without acquiring
power to rise again to fruit-formation ; in the female
flower the latter is attained by an earlier retrogres-
sion of the leaf-formation, suppressing the stamens,

liEJ UVENESCEN CE IN NATURE.

101

whereby space is gained for its new uprising in the fruit-'
formation.*

I;et us now turn from the examination of the undulation
which the metamorphosis of the plant follows in its
greater soarings and subsidings, to the consideration of
the individual steps in which it completes its course, the
single leaves. The leaves present themselves to us as
the single waves in the great stream of vegetable develop-
ment, a stream flowing and ebbing with a periodicity
regulated by law. As we have regarded the sprout as
the first subordinate Rejuvenescence of the plant, as we
have further considered the regions and formations on the
sprout as circles of Rejuvenescence of the metamorphosis,
so have we now to examine the individual leaves (with the
internodes bearing tliem,) as links of Rejuvenescence
within these larger circles. In this sphere, the theory of
Rejuvenescence already presents itself to us in a declared
form and developed into a System in recent scientific
literature,f but truly, in spiteof much thatis to the point

* At the same time, all diclinous flowers do not behave in the same way;
ou the contrary, there exist great and essential differences in the structure
of flowers with separated sexes, which, however, are often diflicult to make
out. While in the cases above considered the unisexual flower presents
itself merely as a one-sided development of an hermaphrodite flower, its
origin depends in other cases, like the sex in animäls, on the different mode
of development of parts, which, according to their position in the flower, are
like, as is the case, for example, in the Willows, in which the same leaves
appear in the male as stamens and in the female as carpels. The observa-
tions which I have made on the so-called hermaphrodite flowers of Care. x, in
particular of Carex stricta, seem to testify the same for this genus. In
Hydrocharis we meet with a case which Stands mid-wav between the two
mentioned modes of origin of unisexual flowers. In this plant the flower is
composed of six altemating trimerous whorls. The first and second (calyx
and corolla) behave alike in the male and female flowers. The third, fourtli,
and fifth, appear as perfectly developed stamens in the male flower, while
the sixth consists of blunt proeesses which sometimes have beeil called stami-
nodia, sometimes abortive pistils. ln the female flower, on the contrary, the
third and fourth whorls appear as blunt proeesses, (staminodia and nectaries
of authors) while the fifth and sixth become fully developed in the form of
carpels.

t C. H. Schultz, ‘Die Lehre von der Anaphytosc oder Verjüngung der
Pflanzen, ein Schüssel zur Erklärung des Wachsens, Blühens und Eruch-
tragens der Pflanzen,’ 1843 ; and ‘ Neues System der Morphologie der
Pflanzen nach den Organischen Bildungsgesetzen,’ 1847.

102

THE PHENOMENON OF

and suggestive, on the whole in a manner of little use,
because deficient in firm morphological foundations.*
Schultz’s theory of Bejuvcnescence makes strikingly
prominent the difference between animal and vegetable
Rejuvenescence : animals repeat, as Schultz expresses it,f
the contrast of living and dying, the unity of which forms
the Rejuvenescence, in all their internal Organs, and tliere
thereby undergo continuous dissolution and reformation,
the etfete parts being at the same time cast off like a
husk. Plants, on the contrary, never rejuvenise an
internal organ once completed, but repeat the contrast of
living and dying only in their outer members, advancing
constantly beyond the completed structures to new pro-
ductions. This peculiarity lies in the nature of vegetable
growth, which goes on solely by repetition of the same
parts, by Anaphytosis . Eor Schultz to combat the theory
of metamorphosis, as he does, by this doctrine of the
anaphytosis of plants, is an inconceivable contradiction,
cutting oft’ all purpose or aim from the doctrine itself.
The doctrine of anaphytosis, which is characterised as the
theory of the constant seif- rejuvenescence of plants
through living repetition of the same parts, aiming at
the object of demonstrating the laws of this repetition
characterising the whole growth of plants, cannot really
stand in contradiction with the theory of metamorphosis of
plants, which, in like manner, leads back to the original
likeness of the vegetable parts or organs repeating thern-
selves in various forms. j Since the links or members of
the Rejuvenescence of the plant (. Anaphyta ) are not
exactly of similar character as they succeed one another.

* This is not the place to carry this out further by demonstration of the
morphological errors in the saicl works ; the botanist accustomed to mor-
pholoo-icaf rescarches finds proof of the above assertion in every paragraph,
e. q ., Tu § 34, where leaves in leaf-axils, and buds in branch-axils of i'orked
stems, are spoken of. See also the critique of Mold, in the ‘ Botanische
Zeitung,’ 1843, p- 667.

•j- Die Lehre von der Anaphytose, 89.

-i- “ The plant represents the most varied shapes by modifications of a
single organ.” Goethe, ‘ Metamorph., § 3.

REJUVENESCENCE IN NATURE. 103

but present themselves in a series of moclifications, the
theory of metamorphosis is necessary to the completion
of the doctrine of anaphytosis , since its object is to
demonstrate the laws ruling over the various modes of
appearance of essentially similar parts, the definite conrse
of transformation of the anapkyta progressing through a
series of stages. As the animal combines a metamor-
phosis with its internal process of Rejuvenescence, so
does the plant also with its extemal , only the metamor-
phosis of the plant, in correspondence with the peculiarity
of its anaphytosis, does not present itself as an internal
recastiug of the organism, as in the animal, but as an
externally projected, many-stepped process of develop-
ment. A doctrine of anaphytosis without recognition of
metamorphosis, robs the plant of its inmost principle of
life, — the principle of development, the graduated reve-
lation of the internal foundation of its existence ; it
denies progress and aim in the processes of vegetable
construction, and is compelled to ascribe the differenceof
the links of the Rejuvenescence to the accident of external
influences, while this is rather the expression of the
gradual triumph of the specific inward essence over
external nature.

If it be true that the plant runs through its metamor-
phoses in a process of Rejuvenescence characterised by a
series of stages and links ; that, to use Schultz’s expres-
sion, it possesses a phytodom, progressing by anaphytoses,
our first object must be to define the links of the Reju-
venescence accurately. But this fundamental condition
of a correct theory of Rejuvenescence, is exactly that in
which Schultz’s exposition is deficicnt. The “anaphyton,”
or simple link of Rejuvenescence, by the continued repe-
tition and manifold combination of which the whole
structure of vegetables is explained, is incleed theoretically
characterised as a totality fitted out with all essential vital
apparatus, and as an independent vegetable individual ;
in what, however, we really discover how the anapkyta
procced one out of the other, and how they combine, is

104

THE PHKNOMENON OE

nowhere clearly sliown ; it is termed a universal morpho-
logical or phytodomic element, the primitive link or
element of all external organs of plants, from the varied
combinations of which are formed the root, stem, and
leaf, which have beeil incorrectly regarded as essentially
different organs of the plant ; — but where the limits of
the single anaphyton are to be found in these structures,
how it is to be recognised in its combinations and
scparated as an independent constituent part, remains, in
most cases, altogether obscure. Much of what Schultz
ascribes to the anaphyton is applicable to the cell ; but
Sclmltz’s anaphyton is not the cell, for Schultz imagines
therein a morphological unity, in which it is essential to
embrace the various principal modifications of the tissue,
as organs of the individual life. Such a morphological
unity, the varied combinations of which would explain
the variety of the external parts of plants, has, in
reality, no existence whatever, as unprejudiced examina-
tion readily sliows. When we trace the anaphyton in
Schultz’s “construction” of vegetable structure, we find the
most diverse things thrown together without the sliglitest
morphological tact..* We meet with the anaphyton at
one time as an internode bounded by nodes, or as an
articulated piece of the petiole of a compound leaf; at
another time, however, as any given piece of an in articu-
lated trunk bearing a bud, or capable of producing one ;
or even as a totally arbitrary piece of a root (as such
without articulations), which is said to be composed of as
inany anaphyta as pieces it can be cut into capable of
producing adventitious buds; further, the anaphyton
appears as a longitudinal strip of a flat leaf ;f lastly,
actually as a circular Rejuvenescence-layer in the inferior

* Schultz’s doctrine is in tliis respcct certainly rnuch more variegated
tlian the “ chaotic hash of the theory of metamorphosis.” ‘ Neues System,’
p. xvii.

t Broad flat leaves are said to originate by lateral ( sympleuric ) fusion
( symphytosis ) of normal stalk-shaped anaphyla. ‘ Neues Syst, der Morph.,
page 2.

REJUVENESCENCE IN NATURE.

105

of the perennial trank.* The parts of the flower again
are regarded partly as simple anaphyta , partly again as
composed of a number of anaphyta. f

When we gather all tliis together, we cannot wonder
that even an admirer of Schultz’s doctrine of the Ana-
phyton says, that it is a Proteus, vvhich we cannot grasp,
and which everywhere slips away from us, yet lies at the
base of all actual shapes.J To those who test the new
System for themselves, in the living plant, it will certainly
be clear from Schultz’s explanation, that this Proteus is
a mere thing of the imagination, existing neither by itself
nor in its combinations, which are forged out of actuali-
ties found in the most diverse sections of the vegetable
organism : sections partly existing as such, partly purely
imaginary. The correct perception that there exist in
the plant multifold phenomena of Rejuvenescence, re-
peated in diverse morphological regions, and subdivisions
( Gliederungen) conditioned thereby, is completely reversed
by Schultz’s System, in that all these perceptible sub-
divisions (not to consider the merely hypothetical) are
regarded as essentially like members of the plant, and

* ‘ Anaphytose,’ § 41.

f The flower is to be couceived only pbysiologically, and not morpholo-
gically (‘ Anaphyt.,’ p. xi), and yet its formation is explained from morpho-
logical elements, i. e. anaphyta (ibid., p. 62). Although composed like
the individual parts of the plant, that is, the parts of the vegetable
“ stock,” of anaphyta , the parts of the flower are said to possess only an
apparent and no real similarity to these, and to be essentially different from
them (p. 67). Since the parts of the flower, as anaphyta, are explained, at
the same time, like the individual parts of the plant, as independent indi-
viduals (p. 92), and since the whole plant is said to repeat itself, with all
its essential functions, in each anaphyton, it is impossible to see, from
Schultz’s doctrine, whence comes the asserted essential difference of the
anaphyta of the same plant. Schultz’s own distinction, namely, the anaphyta
of the vegetable “ stock,” as mere individual (!) (asexual) individuals, and
the anaphyta of the flower {enanaphyta) as sexual individuals, cannot be
regarded as essential, and removing all real similarity, since, on the one
hand, the parts of the flower must still have an individual existence, and, on
the other hand, the anaphyta of the vegetable “stock” must have ascribed
to them, from the production of new anaphyta, not merely individual existence,
but power of propagalion. Hence Schultz’s Opposition to Metamorphosis
appears wholly groundless on this side.

% Vidc ‘Botanische Zeitung,’ 1843, p. 741

106

THE PHENOMENON OF

misused for an atomic theory of anctphyia (< anaphyten -
atomistiJc), which can far less attain to the comprehension
of the living conrse of the sliaping-out of the plant,
developing the parts out of the whole, than even the
atomic theory of cells, since its atom is not a real, like
the cell, but an imaginary nnity.

The repeated attempts to represent the plant as a series
of leaves growing one out of another forwards, and firmly
intergrowing with one another backward, appear to rest
more definitely upon the real and essential subdivisions
of the structure of the plant, and it is no great step from
here to the idea tliat the plant is to be regarded as a
series of generations, the individuals of which are repre-
sented by the leaves, and the metamorphosis of the plant
as an alternation of generations, through which, after
nuraerous preparatory and asexual individuals, the gene-
ration finally arrives in the flower at the fornmtion of the
sexual individuals closing the series.* * * § This attempt to
trace back the whole plant to the leaf-formation, has been
carried out most ingeniously by Ernest Meyer, f and
recently supported through anatomical researches by
Hanstein.J

Here also we refer Gaudichaud’s§ accounts of the
morphological construction of the plant through repetition
and combination of individually independent vegetable
elements ( Phyto. ,) eacli of which is regarded as composed
of three regions; leafabove, internode in the middle, and
root below, — as also the building up of the plant of
stages (or storeys) as explained in the essays of lloch-

* See the explanation, according to tliis theory, by Steenstrup, in. his
‘Alternation of Generations in the Lower Classcs of Animais,5 p. 128.
(Kay Society’s Publications, 1813.)

f E. Meyer ‘Die Metamorphose der Pflanze und ihre Widersacher,5
Linnaea, vi (1S32), p. 401.

+ Hanstein, “ plantarum vascularum folia, caulis, radix utrum organa sint
origine distincla, un ejusdem orgcini diversce tantum partes ? Linnaea,
xxxi (1848), p. 65.

§ Gaudichaud ‘ ltecherches sur l’ürganographie, la Physiologie, et l’Or-
ganogenie des Yegetaux,5 1841.

REJUVENESCENCE IN NATURE.

107

stetter on tke structure of the grass-plant.* All these
attempts to compose the plant of leaves are wrecked upon
the fact of the existence of the stem as an original, inde-
pendent and connected structure, the moreorless distinct
articulation of which certainly depends upon the leaf-
formation, but the first formation of which precedes that
of the leaves. The graduated metamorphosis of the plant
requires the stem as a bridge between the steps ; the
theory of the arrangement of leaves requires it as the basis
upon which the leaves form their regulated ranks ; the
comparative morphology of the lower plants demonstrates
the independence of the stem, since it never shows leaves
without stem, although certainly stem-formation without
leaves ;f finally the history of development brings the
stem before our eyes, in its earliest period of formation,
as the visible foundation, out of which the leaves are
developed.J

* ‘ Jahresliefte des Vereins für Vaterländische Naturkunde in Wurtem-
burg,’ 1847, p. 1 ; and 1848, p. 144. The leaf and the segment of the hakn
beneath it form, according to Hochstetter, a whole, which he calls a stage or
storey C Stockwerk ), and which consists of three parts, the foot (internode of
the halm), the trunk (the leaf-sheath), and the head (the blade of the leaf).
Each new stage is produced from its predecessor by a branch being given
off at the node between the foot and the trunk. ln this way each leaf is
regarded as the terminal Prolongation of the internode of the stem, which
original relation is supposed to be clearly preserved in Juncus, on the round
stalk-like and erect highest leaf (according to Hochstetter, homologous with
the point of the sterile halm), from which we see the inflorescence escape
laterally through a slit. Hansteinalso regards the leaf as terminal, sincche
asserts that each new leaf originates through uplifting of the centre of the
point of Vegetation : “Puncli vegetationis centrum in novum extenditur
folium ,” 1. c., p. 83.

f In the- higher classes of plants even we meet with cases of the develop-
ment of the stem without leaves, as well-knowu in tendrils and thorn-
structures. The sterile halm of the Rushes ( Juncus conglomeratus , &c.)
affords an equally familiär, though less noticed case.

X The recent researches on the commcncement of leaf-formation leave no
doubt on this point. See the works of Schleiden, especially on the origin of
the cotyledons in the embryo and the coats on the nucleus (‘ Wiegmann’ s
Archiv/ 1837, and elsewhere) ; VonMercklin (‘ Zur Entwicklungsgeschichte
der Blatt-gestalten/ 1846 : — on the development of the forms of Leaves,
trans. in ‘ Ann. des Sc. nat., 2d scr. Botanique/ tom. vi, p. 215, 1846) ; Adr.
de Jussieu, on the formation of the embryo of Monocotyledons (‘ Ann. des Sc.
nat/ Juin, 1839); Duchartre, on the organogeny of the parts of the flower
of the Onagracese, Primulacese, Malvacese, Nyctagineae (‘Ann. des Sc. nat./
1842-4-5-8.) Even in the Berns, in which tue leaf-nature of the frond, as

108

THE PHENOMENON OF

A raore detailed examination of the stem from these
four points of view, would lead us too far from onr subject •
but it may be permitted to discuss somewbat more closely
the first point, the import of the stem in reference to
a theory of metamorphosis assuming a vital continuity
and not an atomic composition of the stages. We have
above characterised the leaves as those parts, in the re-
peated formation of which is especially expressed the
Self-rejuvenescence in vegetable life, and through the
successive emergence of which the metamorphosis acqnires
its graduated structure. That tliis gradnated structure
requires a connecting organ, different from the leaves,
and not formed from them, an organ which is not lost
in the individual stages, but rather carries up the process
of development beyond the one-sided development of the
stage, — tliis it is which we would here briefly put forth, so
that we may acquire a basis, out of and upon which the
undulation of the metamorphosis flows. A general
eharacterisation of the fundamental organs, distinguished
by essential differences in the direction of development,
such as the general contemplation of vegetable structure
and vegetable life in its relations to external nature
impresses them upon us, may hencenot be misplaced here
as a preliminary settlemcnt of our position ( Orientirung) .
The difficulty of comprising the phenomena in such a
general view will serve as an excuse for the imperfection
of its execution.

it is called, lias beeil often questioned and disputed, I liave satisfied myself
beyond the possibility of doubt of the excentrical origin of tlic leaves around
a central apex of the stem. Tbc often cll-long creeping subterraneous
stolons of Struthiopteris germanica are clotlied with scale-like cataphyllary
leaves, which on the points of the runners coming up above ground, pass
gradually into the ordinary eupbyllary leaves of the erect stem. Tliey are
arrauged according to the jj type, about an incli distant from each other,
1 incli long, but decurrent for a length of about 2 inclies; tbc unde-
veloped leaves situated on the nascent points are closely crowded. Taking
away all the leaves already more tkan 1 line long, tbere remain still about
8 rudiments, the outermost of which are about g, 3, g of a line high, the rest
searcely measurable. The four innermost appcar as slightly-vaulted pupillae,
gradually diminishiug in size around a central papilla, which is the laigcst,
and therefore cannot possiblv be mistaken lor one ot them.

REJUVENESCENCE IN NATURE.

109

The Vegetable kingdorn, like every kingdom of nature,
eacli of its di vision s, each genus, and each species, has, in
virtue of its peculiar internal essence, its special desti-
nation. With tliis special purpose it enters into the
circle of the multifold life of nature, which meets it partly
as a friend, partly as a foe, partly favouring and bearing
it up towards its object, partly limiting and interrupting
the carrying out of it. Hence, every created thing
which, in realising itself, enters into the totality of natural
life, has to overcome the detracting influence of the lower
kingdoms, above which it has to elevate itself. The
vegetable kingdom is preceded by the kingdom of the
shaped and shapeless elements, the kingdom of inorganic
nature. We behold in this, the kingdom of universal
combination in rest and motion, the kingdom of gravity
and colresion, of universal mechanical antagonism ; in
detail the kingdom of the homogeneous and unchangeable,
in which every change of matter is at the same time a
destruction ; and, where it attains to shape, the kingdom
of fixed and motionless form. Throughout all this
region there is indeed a development of the whole through
detached shaping out of the individual parts, but the
individual parts have no progressive vital development, no
transformation as such, and no Self-rejuvenescence of
being. But above this kingdom of bondage the plant rises
in more emancipated development of life. It acquires shape,
not through a mere act of formation, but through a pro-
cess of development running through different periods,
in which it overcomes more and more inorganic nature
and its bondage, subordinates it as a means, bringing the
peculiar, more highly gifted nature, in it and through it,
to ever freer and more perfect unfolcling. We see the
gradual solution of this problem realised in the metamor-
phoses of the plant. The elevation above the earthly,
merely passively physical, is expressed evenin tlieascending
growth,* which is constantly combined with the progres-

* Sterns growing downwards or creeping liorizontally only occur in the
retrogressive or in persistent low stagcs of metamorpliosis.

110

THE PHENOMENON OF

sive metamorphosis. The single Organs of this gracluatecl
elevation, the links of tlie ascending growth, in which the
internal Impulse towards an increasingly purer and more
victorious representation of its true nature finds its
graduated accomplishment, are the leaves. It is a pe-
culiarity of vegetable life that it fixes itself at each stage,
bringing each to its own permanent and strictly limited
development. ITence each leaf is a thing limited and
unalterably fixed at a determinate stage of the metamor-
phosis.

Since, then, the plant does not exhaust its life in the
single representation, this being rather only a stage beyond
which the metamorphosis advances to new representations,
some organ must exist serving as the means for this
advance, in which the life is not expcnded in the estab-
lishment of the stage, is not terminated in a partial
realisation, but which, retaining its independence, secures
a future development, rises beyond each representation
until the last, as a more active central point, constantly
renewed and sending out new radii, and only loses its
import as an individual centre of formation when the
last and most perfect representation, the aim and con-
cluding structure of the metamorphosis, is attained.
This organ of the plant is the stem or axis. The
stem is not ordinarily continued beyond the last radii,
coinciding with the limited or terminal stage. Its
terminal Prolongation is lost, without any final struc-
ture belonging peculiarly to itself, among the last
leaves of the sprout, whether this concludes with a
flower or not, in the former case, therefore, among
the carpels.* But this must not be supposed to mean

* Among the cxceptional cases in which the stem acquires a development
risiun- beyond the last leaf, or, if it is a lateral sprout, appears in an independent
structure devoid of any leaf-formation, bccoming itself developcd in a radi-
ating manner, are: 1, the free central placenta; 2, emergence into tendril-
fonnation ; 3, emergence iuto thorn-formation ; 4, emeigencc into bristle-
formation ( Seluria , Chenopodium aristatuui) ; 5, the soft needle-like ramifi-
cation of Asparagus; 6, the leaf-like summits of the stems and branches of
Ruscus, Meäeola asparagoides ; and 7, t he above-ment.ioncd sterile halm of

REJUVENESCENCE IN NATURE. 111

that the stem takes no part in the metamorphosis ; for it
is rather in the terminal Prolongation of this, that the
gradual changes of purpose lying at the foundation of
the metamorphoses are prepared, to pass over from it
to the developing radii, so that the stem shows, more or
less strikingly according to the structure of the leaves,
the characters and functions of those leaf-formations of
which it constitutes the support. Thus we see the
lower stem colonrless and devoid of stomates, like the
cataphyllary leaves ; the middle stem green, and furnished
with stomates, like the euphyllary leaves ; that part of the
floral axis which bears the carpels often developed even
into a fruit-structure {Fragarid). Thus stem and leaves
together form one whole, the ascending Vegetation, in
which the metamorphosis is revealed, throwing out its
halting points in the leaves, and advancing, through the
medium of the stem, to further stages.

Opposed to the ascending Vegetation {Pflanzenwuchs),
as a whole, Stands the root , without which the former
would be baseless. In the universal bond of nature all
the higher must rest upon the lower, grow fortli within
and out of this, find its basis and seek the material for
its realisation in the lower realra, and thus as it were,
descend into and absorb the lower, which it is to over-
come. This necessary vital direction, first of all acting
in Opposition to the true purpose, but in the sequel be-
coming again subservient to it, finds its representation
in the root. The root, as a downward growth, is produced
in contrast not merely to the stem, but to the whole
ascending growth of the plant; it originally follows
simply the attraction of gravitation in its growth, pene-
trating perpendicularly downwards, and is diverted into

Juncus, which presents itself alone, in place of the euphyllary formation,
bearing only cataphyllary leaves at its base. The development of these
enormous leafless stem-summits deserves a closer investigation ; so far as I
could trace it, I found nothing which could warrant the idea that these
green halms were leaves, in particular no sheath at their base. The smallest
and youngest that I could dissect out always appeared as elongated conical
points, and no otlier punclum vegetationis could be distinguishea.

112

THE PHENOMENON OF

deviating directions only in its branches. Thus it gives
tlie plant its basis and connection witli the inorganic
soil, and especially supplies that material, by the assimi-
lation and Subordination of which the entire plant
becomes realised. In correspondence with its direction
of growth, it forrns a contrast to the total ascending de-
velopment of the plant ; it therefore has no metamorphosis.
For the same reason it is devoid of leaves, these being
the steps in the course of the metamorphosis.

Thus, then, steni, leaf \ and root present themselves as
essentially different parts of the vegetable organism, as
its fundamental Organs depending on the diffcrence of
the directions of development of vegetable life. The sure
and exact distinction of these forrns the basis of Morplio-
logy. That the study of the lower plants leads us to
structures in vvhicli the different directions of vegetable
life do not appear clearly distinguished, is no reason wlry
we should deny their essential and inconvertable difier-
ence when they present themselves really separated, as is
almost everywhere the case throughout the higher classes
of the Vegetable kingdom.

Leaves and stein form together, as above remarked,
one wholc, opposed to the root ; if we regard the leaves as
rays, the stein forrns the eentre, necessary to the idea of
the rays ; if we regard them as waves, the stem represents
the lcvel on which the undulations origin ate, forming the
troughs between the waves : a mode of viewing the phe-
nomena suggested by the theory of the arrangement of
leaves. Not only in the fully-developed leaf, do we see that
it is not sharply cut off from the stem, but runs gradually
into it, as sliown in the formation of th epulvinus, in decur-
rent margins, &c. : tliis is indicated even in the earliest
appearance of the leaf, primarily a scarcely distinguishable
papilla, extending laterally into a little ridge (running back
as it were into the stem), the papilla sinking down outside
(below) quite gradually into the stem. How the leaf is
really formed, how it takes its first origin in the stem, and
by growth emerges from tliis, is a problem which the

REJUVENESCENCE IN NATURE.

113

research, recently so industriously devoted to the history of
development, has not yet beeil able fully to solve. The idea
of Schleiden, that the leaf is pushed out, as it were, from the
stem, the apex first emerging, and the lower parts being
gradually extricated by development at the base,* is devoid
of exact demonstration, which can only be given by a com-
plete history of the development, accurately illustrating
the succession of the individual cells, of the apex of the
stem, and the rudiments of the leaves arising from it,
which certainly exist before they are elevated as papillae.
The assertion of Schleiden, that the leaf is formed by a
process of cell-formation advancing from the apex to the
base, has beeil contested by Nägeli,f who, resting 011
complete observations 011 the formation of the leaf in the
Florideae, Characese, and Mosses,^ sets up the contrary
doctrine, that the original growth of the leaf advances by
cell-formation at the apex and at the circumference, that
is, from the base upwards and outwards, and that only
the later growth, connected with final completion of the
structure of the leaf by expansion of the cells, begins at
the point and circumference, and progresses towards the
base. TIow far these results, derived principally from
the Cryptogamic plants, are applicable to the leaf-forma-
tion of the Phanerogamia, can scarcely be safely deter-
mined, from the deficiency of researches on the latter.
That supplementciry cell-formation, presenting itself in all
or only isolated parts of the first cellular structure, fol-
lowing the original cell-formation (doubtless progressing
according to accurately defined rules in the higher no
less than the lower plants), that supplernentary develop-
ment which Nägeli calls abnormal or accidental, appears
to be of great importance to the ulterior development of

* Sclileiden, 1 Grundzüge du Wiss. Botanik,’ ii, 113, (2d Ausg.) ‘ Prin-
ciples of Scientific Botany’ (London, 1849), p. 261.

t ‘Ueber das Wachstlium und den Begriff des Blattes,’ Zeitsehr. f. wiss.
Botanik, 1847, 153; ‘ Wachsthums-geschichte der Blätter der Laubmoose,’
Ibid, 1845, p. 175.

+ With regard to the two last-named families, I can fully confirm Nägeli’s
observations through my own.

8

114

THE PHENOMENON OE

the leaf of the Phanerogamia ; but timt Schleiden’s theory
of leaf-formation is only partly warranted, even in tliis
second stage of growth, is shown by Grisebach’s dis-
covery, that several points of Vegetation or foci of develop-
ment frequently present themselves within the leaf, and
an intercalary cell-formation occurs not only at the base,
but at various points.* * * § Even the last stage of growth of
the leaf, depending on the mere expansion of the cells,
does not always, or in all parts of the leaf, progress in
the descending (centripetal) direction, as followed indis-
putably, even before Grisebach’s researches, from the
observations of Steinheil (especially on the leaf of the
Magnolias ) and Munter (on pinnate leavesf), although tlie
difference between the growth by cell-development and
cell-forination was not actually distinguished in them.J
The general and partial graduäl unrolling, advancing
toward the apices, and the final expansion of the Eern-
leaf connected witli tliis, is a well-known phenomenon,
whicli has been incorrectly regarded as an evidcnce
against the foliar nature of tliis organ. §

* Grisobach, 'Beobachtungen über das Waclistlmm der Vegetations
Organe in Bezug auf Systematik.’ (Wcigmann’s Archiv, 1844, 134.)

-j- ‘ Obscrvationes sur la mode d’accroissement des fouillcs.’ (Ann. des Sc.
nat. 1837.)

% ‘ Beitrag zur Lehre vom Wachsthum der Pflanzen,’ Bot. Zeit., 1843,
p. 785.

§ Especially reraarkable, in tliis respcct, are certain Berns, in whicli the
points of the leaves are never totally unrolled, as in the uarrow, simply
pinnate Platyzoma microphyllum , and the Jam.eson.iee resembling tliem in
Iiabit (c. (/■ J. imbricata, Hook, et Grev., t. 178, scalaris, cinnamomea , verti-
calis Kunze, ‘Die Earrnkräuter in Colorirten Abbildungen,’ t. 71 and 82).
Still more rcmarkable are many species of Gleiclienia and Merlensia, in whicli
the development of the leaf is arrested above the first pair of pinnules (and
in multipinnate rudiments often repeated in several degrecs of the ramifi-
cation), so that the point, seeming to form a bud in the bifurcation, eitlier
remains permauently undeveloped, or is only unfolded in the succeeding
season, and tlien again in like manner only imperfectly. Tliis sectional
development of the leaf, in whicli we beliold one of the most remarkable
phenoinena of Rejuvenescence within the leaf itself, appears eapable of
Lasting through many years, on whicli liead it would be very desirable to
obtain more accurate Information from observers in the native countries of
these Berns (see Kaulfuss, ' Das Wesen du Earrnkräuter’), 1827, p. 3G).
That the leaves of these Berns do not possess, however, as might seem, an
unlimited growth, is proved by the leaves of the young Mertenaim witli a

ItE J U VEN ESCEN CE IN NATURE.

115

The tendrils of the Cucurbitacese, certainly belonging
to the leaf-formation, behave, leaving out of view the
suppression of the blade-formation, exactly in like man-
ner, and the pinnate leaves of the Dicotyledons have not
only a centrifugal expansion-growth of the petiolar
apparatus ; but the lateral leaflets unfold distinctly in
ascending order, while at the same time eacli individual
leaflet completes its own growth by a centripetal ex-
pansion.*

In spite of the imperfection of our insight into the
laws regulating the formation of the leaf, we may at
least regard it as certain, that the leaves are developed
forth from an axis formed before them, and that this
axis, whenever leaf-formation occurs, is developed into a
stem after the rudiments of the leaves have come into
existence ; it may be further regarded as certain, that
the formation of the leaves is not simultaneous but suc-
cessive ;f so that between two following leaves there
always exists at the outset, a separating structure, the
axis, permanent as such, whether it may be developed as
an internode or not. If we conceive the leaf in relation

similar apiculated terminal structure, of which Martius (‘ Icones plant,
crypt.,’ t. 60, il) has represented an interesting series, but erroneously
referred to a distinct species (M. pumila). The Uymenophyllum interruptum
figured by Kunze (‘ Anal, pteridograpb., t. 30), likewise deserves mention
here.

* The phenomenon may be seen especially well in the Mahoniee witli
pinnate leaves, the lower pinnules of which are already expanded, green,
and coriaceously hardened, while the upper are still scarcely half as large,
half folded together, reddish, and soft.

(Vide also ‘ Proceedings of the Linnean Society of London,’ May 6th,
1852, in a paper by Dr. Alexander on the leaf of Guarea grandifolia, Dcne.
In this the upper leaflets are developed after the lower have fallen off,
periodical growth at the apex of the petiole going on l'or several years. — A. H.)

t This nolds good even of the leaves of whorls, as transitions and sub-
stitutions of verticillate and spiral arrangements suflicicnUy testify.
Although recent observations on the development of the parts of the
flower describe the circles of papillae, forming the earliest representatives of
the circles of the flower, as Corning to light simultaneously in all the segments,
we must remember that these papillce are by no means the earliest rudi-
ments of the leaf-formation, but that to solve this question by means of the
history of development, it would be necessarv to go back to the origin of
the cells, or groups of teils, which subsequently rise up as papillae.

116

THE PHENOMENON OE

to the axis, as a ray, ov in relation to the spiral series to
which it belongs, as a wave, we recognise in any ease, in
the intim ately connected origin of the stem and leaf, an
alternation of emerging and retiring formation, of rising
and sinkin g, radiation and concentration ; and this it is
which we have characterised above as a course of de-
velopment advancing in repeated acts of llejuvenescence,
as it were in an undulating flow of the metamorphosis.
This would be the place to examine the definite pro-
portions which the leaf-formation adheres to in its spiral
undulation, and the conditions of arrangement of the
leaves arising from tliese ; to trace them from the simple
rudimentary plans ({, h) with which the plant, as a whole,
commences and which arc mostly repeated at the begin-
ning of a new brauch, through all the complications
which come in during the progress of the metamorphoses,
and mostly attain thcir maxinmm in the hypsophyllary
region ;* tlien, further, to sliow how the simpler plans
(a> Ij 3») recur, but in cyclic combination, in the flower,
how here a new series of complications is established in
the harmonious combination of the cycles, and how finally
in the fruit, the arrangement frequently retnrns to the
simplest condition. But to carry this out would dem and
an exposition of the theory of Phyllotaxy, which would
far exceed the limits allowable in the present treatise.

Note. — The more recent researches on the Phyllotaxy
of Plants will be found compared in Schleiden’s ‘ Grund-
züge/ 2te Ausg.ii, p. 1 77 (‘Principles of Botany,’ pp. 263-6),
to which are to be added, a later treatise by the brothers
Bravais (‘Essai sur la disposition generale des feuilles
rectiseriees/ 1840), an essay by the Swede Silverstrahle
(translated in Hornschuch’s ‘Arcliv. scandinavischen
Beiträge/ i, p. 382), agreeing in its conclusions with the
first treatises of the brothers Bravais ; and the works of

* Yide Compositse, Dipsaceaj, Plantaginese, Proteacese, Pipcracesc,
Zingiberaceai, Cyperacese, Aroidese.

REJUVENESOENCE IN NATURE.

117

Naumann, wliich, originally scattered throughf Leonhard
and Bronn’s ‘Jahrbuch der Mineralogie’ (1842), and
Poggendorff’s ‘Annalen’ (1842-43), were subsequently
eollected by the author into an independent treatise
(Ueber den Quincunx als Grundgesetz der Blattstellung,’
1845). Since I have indicated the occurrence of simpler
and more complicated conditions of the arrangement of
leaves, and a determinate cycle in wliich fliese appear in
the plant, I may be permitted to introduce here inci-
dentally an observation on the actual existence of series
of different conditions of arrangement, as asserted in
Scliimper’s, and my own works, but questioned in the
essays of the brothers Bravais. I feel the greater in-
clination thereto from a remark of Schleiden (‘ Grundz.,’
p. 176; ‘ Principles,’ p. 265), who characterises the theory
of the Bravais, who sought to trace back to a single,
irrational angle of divergence, alike for all, the modes of
arrangement regarded by us as different and expressed
by a series of rational divergences, as far preferable,
since it indicates a simplicity of the law, and under like
possibilities that explanation is always to be preferred
which embraces the greatest n umber of cases under one
point of view. But the theory of rational divergences
which first recognised as such the multiformity of the
cases which observation reveals, and then strove to
subordinate them to a general law, should have beeil
upheld on this very ground, in Opposition to a theory
which, in contradiction to itself, first denies the multi-
formity of the cases, to insinuate under them an ab-
stract unity, and subsequently (in the second part)
canuot avoid admitting that the rational and in reality
dissimilar cases do occur in plants. To deny the multi-
formity of nature without sufficient proof is certainly not
the right way to introduce unity of law into phenomena.
The assertion of the Bravais that all supposable arrange-
ments of leaves of the main chain are formed on a plan of
equal irrational divergence, is just as contrary to nature
as a System of erystallography would be that denied the

118

THE PHENOMENON OF

existenee of all the forms of a regulär System bounded by
a definite immber of surfaces, on the ground that they all
belonged to a single series terminating in the sphere, a
surface without any boundaries. I am farfrom inten ding
by this to take away all value from the labours of the
brothers Bravais ; the more complicated modes of ar-
rangement are often so difficult to distinguish that the
doubt as to their existenee, as actually different, is often
readily explicable, but, on the other hand, in the simple
conditions, there cannot be the slightest doubt that they
exist in the greatest mathematical accuracy, which indeed
is admitted by the Bravais themselves. Hence arises
with the Bravais a diversity of explanation of phenomena
which evidently belong to the same series, a circumstance
which by no means harmonises with the formulary praisc
which Schleiden gives to the theory of Bravais. Schleiden
would certainly not have arrived at such a judgment had
the subject of phyllotoxy been more experimentally
familiär to him. At the same time, the question here is
not so much of the preference as regards metliod of a
theoretical exposition, as the establishment of a series of
facts. I eite in support of my own convictions, gained by
ui any years’ study of the modes of arrangement of leaves,
an observer whose trustworthiness is declared by most
important labours in an analogous field. Naumann has
not the least doubt of the actual and distinguishable
occurrence of most complicated conditions of arrangement
(_m} >**,) and refers the incredulous to the investigation

of the Cactacem and Compo^itse, remarking that in the
sun-flovver, a blind person will be able to distinguish the
above-named allied plans of arrangement with the fingers,
although they depend upon immeasurably small differences
in the angle of divergence (Poggend. ‘Anna!.’ 1843, p.

55zj< 55). According to my own and Naumann’s

(. TJeber den Quincunx, pp. 70—71) observations, not only
1 and | occur in the Cactese but also | in a manner
which even Bravais could not help acknowledging as not
merely apparently but actually rectihnear and rational.

REJUVENESCENCE IN NATURE.

119

These niost clear and decisive cases belong chiefly to the
genus Echinocactus, in wkich, in combination with a
most crowded arrangement of the leaves, the pulvini of
the leaves are blended in vertical lines, so that these pre-
sent themselves more clearly than all oblique lines. If,
then, in another genus of the Cactacese (. Mamillaria ), the
usually still more complicated modes of arrangement are
less easily and surely distinguishable, because the leaves
are not so closely crowded and the pulvini are separately
developed, we certainly must not conclude from this that
we have here a different irrational mode of arrangement,
essentially distinct from the rational arrangement of the
Eclänocacti. As regards Naumann’s method, of ex-
amining, measuring, and naming the arrangement of the
leaves from the point of view of the vertical lines, it may
be added that within a certain domain this has the same
practical applicability as the mode of defmition and de-
nomination founded on the fundamental spiral ; but if we
go back to the genetic succession of the leaves, which is
indubitably represented in the fundamental spiral, Nau-
mann’s method appears contrary to nature. While on
the one hand it appears to afford a simpler explanation of
the verticillate arrangement, on the other hand it is inca-
pable of expressing, even in the formula of nomenclature,
the actual and essential connection of the verticillate and
spiral arrangements as the transitions in the plant deinon-
strate them, whence it must appear especially useless in
the department of anthonomy or construction of diagrams
of flowers. Schleiden further makes the objection to the
whole study hitherto of the phenomena of the arrange-
ment of leaves, that it has kept solely to fully-developed
plants, instead of tracing the subject in the liistory of
development, whence all theories are devoid of safe foun-
dation (1. c., p. 175, Transk, p. 264); in this he is partly
right and partly wrong, for everything has its time.
What is requisite in the first place is an actual review of
the conditions of arrangement of leaves occurring in the
vegetable kingdom, the mode of their occurrence, their

120

THE PHENOMENON OF

distribution in plants, their transitions and alternations,
and all this can only be afforded by a more or less per-
fectly-developed condition of the plant. A sufficiently
large number of leaves must have been formed before we
can safely judge of tlieir arrangement, since a measure-
ment of the divergence of the earliest rudiments of the
leaves is as impracticable as every later direct measure-
ment. Hence the investigation of the earliest rudiments
in reference to this point will be of little use until the
condition of arrangement of the full-grown plant is known.
Even those conditions frequently coming with the com-
pletion of the development, disturbing the original
arrangement, as forcxample,the unilateral pushin g together
of the leaves when there is unequal thickening of the
sides of the stem, the moving back of leaves by unequal
adhesion of the base, the apparent change of the arrange-
ment of the leaves from revolution of the stem, &c.,
require no great research into the rudimentary structure
to set them aside. Thus the method of determination
may be perfected, without directly tracing the first origin
of the leaves, to such a degree that the modes of arrange-
ment are almost everywliere to be arrived at, and a com-
parative investigation, carried out properly by means of the
method we possess, is capable of bringing Phyllotaxy to
such results, that it makes each individual case compre-
liensible in orderly Connection with the entire System of
the arrangements of leaves. The true side of Schleiden’s
objection is, that this is not the final result, the final
establishment of Phyllotaxy, since for its completion we
necessarily require the elucidation of the connection ofthe
external arrangement of the leaves with the internal
arrangement of the cells in the apex of the stem, from
which the leaves emerge, and in which, simultaneously
with their origin, is laid the foundation of their
arrangement, — a problem toward the difficult solution of
which, the study of development has not yet made the
slightest step, at least in the realin of the Phanerogamia ;
moreover this also includes the explanation of the organic

REJUVENESCENCE IN NATURE.

121

processes in the cells themselves, through which their
arrangement is determined, as well as the forces with
which the organism works ; in a word it inclndes at its
final point the Physics of Organization, of which botanical
Science has at present scarcely a foreshadowing. There-
fore, everything at its proper time!

III.— CELL-FORMATION.

In proceeding to the subject of Cell-formation, we pass
over a series of phenomena of Rejuvenescence which
should be intercalated between the second and third
sections, namely, the processes of Rejuvenescence which
frequently occur in the development of the leaf itself, and
through which the leaf acquires its subdivision and com-
pound nature, — as well as the Rejuvenescence of growth
also occurring in the ulterior completion of the parts of
the leaf, of which we liave spoken already in examining
the leaf ;* we farther pass over the phenomena of Reju-
venescence in the later completion of the stem, which
occur both in the longitudinal growth and the increase of
thickness, the former especially as intercalary growth of
the internodes,f the lateral as periodically renewed
growth of the cambium zone of the stem, between the
wood-mass and the bark, whereby origin ate the annual
rings in the trunks of the Coniferous and Dicotyledonous
trees. All these, as well as the already examined phe-
nomena of Rejuvenescence, necessarily lead finally to the
consideration of the cell, as the simplest sphere of
formation in the course of the life and growth of the
plant, from which all development starts, which in infi-
nitely varied repetition and modification accompanies the
entire development, and to the independent representa-
tion of which the conclusion of the development once

* See pagc 113.

t Sec Griscbacli, ‘ Ueber das Waclisthum der Yegetationsorgaue,’ Wicg-
mann’s ‘Archiv,’ 1843, i, 207.

122

THE PHENOMENON OF

more returns. The Investigation of each link, of each
organ of the plant, leads back to the simple cell : the
formation of the stem advances by division of a simple
apical cell ;* * * § the formation of the leaf starts from a
single lateral cell in the vicinity of the apex of the stem ;f
every lateral sprout is originally a cell, which, instead of
remaining as a mere part of the tissue of the parent
sprout, becomes the primary cell of a new developmental
series.j To penetrate every where to these first rudiments
of structure, to follow out from them the course of deve-
lopment of the tissues of all parts, and to make out the laws
according to which the cell-formation progresses to pro-
duce the various arrangements on which the structure of
the plant essentially depends, is one of the most difficult,
but, at the same time, most profitable tasks, totlie accom-
plishment of which Nägeli, in particular, has quite recently
opened the patli by accurate and methodical description
of the history of the cell-formation and growth of numerous
plants bclonging to the lower Orders of the Vegetable
kingdorn, from which alone the way can gradually be
levelled up to the higher. §

The investigation of cell-fonnation is no less necessary

* Definitely demonstratcd in the Plündere, e. g., in Polysiphonia and
llcrposiphonia (Nägeli, ‘ Zeitschrift,3 lieft 3 and 4, p. 207, t. 6-8); Delesseria
hypoglossum (idem, lieft 2, p. ] 21, t. i); Laurencia (Nägeli, ‘ l)ie neueren
Algcnsystcmc,’ t. 8, f. 4); Characere, Musci (Nägeli, ‘Zeitschrift,’ lieft 2,
p. 138, t. 4) ; Equisetaccre (idem, lieft 3 and 4, p. 167). If the apical cell
divides vertically into two equivalent cella, consequently into two apical cells,
dicliotomy rcsults (see Pictyola , in Nägeli’s ‘ Algensysteme,’ t. 5, figs. 12-16),
and by rapid repetition a fan-like expansion. Probably the fasciation, as it
is termed, of the Phanerogmia, originates in tiiis way.

f So at least in the Eloridere, Gliaracere, and Mosses. (See Nägeli in the
already mentioned places.)

+ See the formation of branches of Tücliinomitrion furcatum, in Nägeli’s
‘ Zeitschr.,’ heft 2, p. 138, t. ii, ligs. 1-6. Amongthe cases of which we liave
an exact description, is also the origin of the seed-sprout or ovule of Orchis ,
which, according to Hofmeister, (‘Enstehung des Embryo der Phancrogamen,’
1849, p. 1, t. 1) is developed from a single cell of the placenta, which is
first divided into two superposed cells, the upper of which by subsequent
division l'orms the cellular coat, the lower the axial row of cells.

§ See the treatises relating to tiiis in Nägeli’s ‘Zeitschrift für wiss.
Botanik.’ (1845-47), as also his ‘Kritik d. neuer. Algensysteme u. Ycrsuch
eines eigenen Systems d. Algen und Florideen,’ 1847.

REJUVENESCENCE IN NATURE.

123

in physiological than in morphological respects ; for to
the cell is committed all the vital activity of the plant ;
the material and form of the plant are produced in and
through it. In the cell resides the wonderful power of
preparing the organic substances, which no other Chemical
laboratory has the means of forming ; in it the force of
endosmotic absorption and excretion, and that admirable
circulation, not yet physically explained, by which the
contents are, in the most varied manners, either imper-
ceptibly diffused, or driven in active currents ; in it the
force of organic production of form and of growth, and,
finally, the force of transformation and reconstruction, on
which depend the multiplication and propagation of
plants. The cell is, therefore, the immediate focus of
Rejuvenescence, the point from whence come all the
phenomena of Rejuvenescence in the building up of the
articulated (or complex) organism of the plant. Hence,
if we wish to become intimately acquainted witli the
phenomenon of Rejuvenescence, we must search it out in
the cell itself. ln the outset we distinguished two periods
in the process of Rejuvenescence, the period of retro-
gression, of solution and removal of the old, and the
movement of renewed progress, the repeated construction
and reformation ; accordingly, after a preliminary con-
sideration of the formation of the cell in general, we shall
examine the phenomena of Rejuvenescence in the life of
cells in detail, — in the Destruction ( Entbildung ), and
Reconstruction (. Neubildung ) of cells.

I. FORMATION OF THE CELL.

Cell-formation is one of the most essential peculiarities,
one of the most constant characters of the plant. In
cell-formation, especially, the vegetable organism shows
itself to be determined in its formation from within ;
through this the plant cuts off its structure, as a whole,
as in the smallest subordinate sphere of life, from with-

124

THE PHENOMENON OE

out, interposing a boundary structure, the cell-membrane,
as a medium for the intercourse with the external world,
and a protection from direct attack. Although the plant
be developed almost infinitely through the unlimited
nature of the process of sprouting, its life appears in
every cell (with a few exceptions) as in a circumscribed
and in a peculiarly inwardly determined spliere of forma-
tion, so that the cell also is, in a certain sense, an indi-
vidual, and, in fact, has been pre-eminently regarded as
the individual of the plant by many authors.*

As the single plant begins with a simple cell, so does
the Yegetable kingdom. In the lowcst stage of tliis the
plant presents itself as a simple cell, and the first repe-
tition of cell-formation is, at the same time, propagation.
The farther we trace up the stages of the Vegetable
kingdom from tliis point, the greater is the multiplicity
of the division of the originally simple spliere of life into
subordinate spheres, and the more frequently is the cell-
formation repeated : the vegetable organism becomes
multi-cellular. Wliilc the cell eonstitutes actually the
solc individual of the plant in Uni-cellular plants, in
the higher plants it becomes a spliere of formation sub-
ordinate to the more developed individual organism.
With the less perfect Organisation of the plant, as com-
pared with that of the animal, with its peculiar deficiency
in a permanent and thoroughly pcrvading central relation
of the parts, the vegetable cell, as a subordinate part of
the organism, possesses a far greater individual independ-
ence tlian the cell of the animal tissue, manifoldly changed
in its structure, and more insolubly connected to the
whole.

Unicellular plants, in the strictest sense, are repre-
sentcd properly only by tliose in which the whole cycle
of life is completely shut up in one cell, the first recon-
struction or division being at once the commencement of

* Schleiden, ‘Grundriss der Bot.,’ p. 28, and ‘Grundzüge,’ 11, p. 4.
(‘ l’rinciples of Sc. Bolany,’ London, 1849, p. 126.)

RE JU YEN ESC EN CE IN NATURE.

125

a new cycle ; in which, cousequently, the whole vegetative
life is run through in the same cell where the propagation
also finally appears. But in a wider sense, there are
other Unicellular plants, if, namely, we regard those as
one-celled, in which the conclusion and renovation of the
cycle by the formation of a germ does not occur until
after several generations of cells, yet the vegetative life is
passed through, not in a rigidly combined series of cells,
but in separate cells.* * * § These cases are of two kinds.
In cases of one kind the vegetative life is really corapletely
shut up in one cell, but the formation of germ-cells in
this cell is attained, not directly, but through the medi-
ation of one or more transitory generations of cells. f
Such plants are truly Unicellular, as far as regards Vege-
tation,! since the transitory cells neither possess a special
and peculiar vegetative development, nor contribute to
the formation of a uniform vegetative tissue, but appear
only as a rapidly over-passed, transitional stage previous
to the formation of germ-cells, — as germ-cells, as it were,
which divide once or more times before tliey arrive at the
point from whence a new vegetative cycle can begin
again with germin ation. § In the other cases the multipli-

* Unicellular plants occur in the series of F ungi and Algse, which have
very varied correspondence in morphological respects. In regard to the
latter I refer to Nägeli’s most recent work (‘ Gattungen einzelliger Algen/
1849), in which is laid a new and solid foundation for the knowledge of these

Elants, so interesting in this respect, but hitherto (with the exception of the
Jiatomaceae and Desmidiacese), from want of observation on the development,
only most superficially known, and heaped together in the most chaotic
manner in the Systems of Algse.

t Vide Nägeli, ‘Einzelliger Algen/ p. 28.

X In systematic respects, also, the unicellular genera are most closely
connected, since many genera with transitory cell-formation in the passage
to spore-formation exhibit great agreement with those without this (except-
ing in this one character). Thus Cystococcus, Näg. (1. c., p. 84, t. 3, e),
with transitory cell-formation, corresponds with the genus Protococcus (as
limited by Nägeli), with immediate or simultaneous spore-formation; C/mra-
cium , A. Br. (Näg., 1. c., p. 86, t. 3, d), perfectly corresponds to the genus
Ascidium, A. Br. ; Pediastrum, Meyen, in many respects to the genus
Hydrodidyon, Roth.

§ This case is repeated in multicellular Algse, Ulothrix, Ulva, Porphyra ,
(Nag. ‘ Algensyst./ t. 1, f. 61, 62), Eclonarpus , (ibid., t. 2, figs. 3, 4, 5);
similar cases occur even among the Fucoidese, since, according to Dccaisne

126

THE PRENOMENON OF

cation of the cell happens in the vegetative sphere, the
cells increase in n umber by a succession of divisions
before the vegetative cycle closes with fractification ; but
the plant is incapable of keeping intimately connected the
generations of cells thus produced, of building forth the
organism as a whole, in these divisions ; it breaks np
more or less completely into the individual cells, which
thus, although merabers of a definite cycle of Vege-
tation, lead a separate individual life. We see that
which is completed by the higher plants in an orga-
nically connected series of cells, represented liere by
an alternation of generations of unicellular vegetable
individuals.* It is therefore impossible to draw a
strict line between Unicellular and Multicellular plants
in tliis respect, since there exist numerous intennediate
stages leading from the most intimate Union to total
Separation.

The completion of the contrast of growtli and dif-
ferentiation of the organs does not always keep pace with
the siraplicity or complexity of the tissue. Even among
the Unicellular Algm, raost strictly so called, we find the
general Opposition of growth of the plant expressed more
or less distinctly in the unicellular individual ; in fact
we find that the very fundamental organs of the plant,
stem, leaf, and root may be represented with more or
less evident distinetness by parts of one and the same
cell. The graduated succession which we detect, in this
respect, among the Unicellular Algse, is so well adapted
to enlarge the ordinary conception of the cell, that we
cannot omit a brief examination of it liere.

The simplest condition of the unicellular plant would

and Thuret, the originally simple spore of Fucus canaliculatus breaks up
into two, that of F. nodosus into four, of F. serralus and vesiculosus (doubt-
less by repetition of division) into cight spores. (Yide Decaisne and Thuret,
‘ Sur les Antheridies et les Spores de quelques Fucus,' ‘ Ann. des Sc. nat.,’
1845.

* Here refer the Diatomacese, Desmidiacere, and most of the Palmellacem.
For the course of the generations of the first, see Thwaites ‘ Further Observa-
tions on the Diatomacese,’ (‘Ann. and Mag. of Nat. Hist., 1848, sec.
ser. i, 161.)

REJUVENESCENCE IN NATURE.

127

be, when the cell exhibited no other difference of its
sides and parts beyond the contrast of contents and
membrane, therefore was completely uniform over its
whole periphery. According to the description Nägeli
gives of bis family Protococcacese, Protococcus * may be
regarded as the representative of this stage, being a
genus of wliich the individuals are globular cells, pro-
ducing free, likewise globular germ-cells, in their contents,
after their vegetative growth is completed. But it
appears to me doubtful whether, strictly speaking, such a
condition of the cell, completely equal in its relations to
all sides, ever occurs. If Protococcus , as is probable,
possesses moving (swarming) germ-cells, these cells will
doubtless be found to exhibit, in the moving stage, an
elongation, so as to liave a principal axis, and two
different extremities, one of which bears the cilia, while
the coloured contents of the cell are crowded into the
other. In Hydrodictyon, which genus must likewise be
included in the family of Protococcacese, the cells, con-
nected into a net-like colony, have also a distinct longi-
tudinal extension in their ulterior development, without,
liowever, any difference in the two ends, since the
extremities are both joined in a similar manner to the ends
of the adjacent sister-individuals to form the network.
But a distinct contrast between the upper and lower end
of the cell presents itself in the same family, in the genus
Ascidium, the free cells of which attach themselves to
foreign objects by one end (that elongated and bearing
the cilia at the period of swarming), whilst the free
extremity (originally the more obtuse) becomes prolonged
into a short point. In the tubulär cavity of the cell, the
contents form a coating over the inside of the wall, by a
simultaneous division of which, after the vegetative
developmentis completed, numerous germ-cells are formed,
finally swarming out of the expanding mother tube,

* According to Nägeli’s limitation of this cliaotic genus. (Vide Niigcli,
* Die neueren Algensysteme,’ p. 158.)

128

THE PHENOMENON OE

which becomes torn at the side or bottom.* The con-
trast in the development of the upper and lower ends
of the cell presents itself still more strikingly in Botry-
dium. The young plant is a globular cell, which might
be readily mistaken for a Protococcus, but, with further
development, a hyaline Prolongation is produced below,
penetrating into the eartli and branching like a root,
while the upper part of the cell swells up more and more
into a large obovate vesicle. The mucilaginous contents
form a lining to the walls, containing numerous Chloro-
phyll vesicles. After the growth is complete, numerous
germ-cells are formed out of the lining coat of the wall,
and these do not appear to swarm, but are set free by the
membrane of the parent-cell becoming gelatinously
softcned, collapsing, and finally dissolving. In Vaucheria
the lower part of the cell grows out in like manner into
a branched palc-coloured root, and the upper part is
elongated in a still more considerable dcgree into a
stem-like filament, which grows on and on by apical
development until its growth is finally arrested by fruc-
tification. From the ascending filament arisc lateral
prolapsing branches, endowed with special faculty of
apical growth, some of these being large and erect like the
main stem, others small and divergent. A single moving
germ-cell is produced in the point of each erect brancli ;

* Ascidium acuminatum , A. Er., occurs ncar Freiburg, in waterbuts or
troughs, or on stoncs or confervsc in rills flowing from springs. It resembles
in aspect Characium Sieboldii , A. Br., occurring in similar situations, from
which it is easily distinguishcd by the more bulging form of the cell, more
apiculated at the apex, and never containing more than one starch-vesicle.
The swarming germ-cells are j^th — TJsth of a millim. long, longish, and
furnished with two cilia at the narrower end, 1| to 2 times as long as the
germ-cell. After the germ-cell has settled down by the ciliated end, the
plant grows rapidly, is at first slender and attenuated upwards and dowu-
wards; subsequently it becomes bellied out, almost ovate, running out
suddenly into a sliarp point above. The full-grown cell is about „fe millim.
long. While young, the cell *is filled up uniformly with green conteuts,
later they form a rather thick coat ovcr the wall, uneveu on the inner free
surface. When the formation of germ-cells commences the starch-vesicle
disappears, and the coat lining the wall becomes subdividcd into 50 GO
gonidia.

REJUVFNFSCENCK IN NATURE.

129

in the horizontal branchlets are formed, in each case, one
thick-coated, resting spore.* * * § Bryopsis goes still further
than Vaucheria in the development of different parts
from one and the same cell j for in this the cell
produces roots on one side, and, on the other, erect
stems, with apical growth, multiplying themselves by
ramification. On these stems are formed distichous, or
spiral series of shorter branchlets, with limited apical
growth, these clothing the stem like leaves, and finally,
when the canal of communication Avith the stem has
become closed up, falling off like leaves. The numerous
moving germ-cells of Bryopsis f are formed in these
branchlets. The genus Caulerpa% forms the last link in
this series of remarkable shapings of the simple cell.
In this the undivided cell forms in its development a
creeping stem, growing on ad Infinitum at its apex,
from which (besides inessential branches, repeating the
main stem, and, like it, unlimited,) proceed two kinds of
branches with limited growth, different from each other
and from the main stem, narnely, to the under side
divided roots, to the upper leaf-like branches which,
originally cylindrical, expand into laminse in subsequent
growth, and present different forms according to the
species ; in Caulerpa prolifera, for example, lingulate and
obtuse, in C. denticulata § broadly lanceolate, deeply
toothed, and somewhat acute, in C. plumaris pinnatifid
or cut like a comb. Much as these strnctures remind us,
by their form, of the stem-leaves of the higher plants,
they are merely hollow prolongations of the one cell,

* Vaucheria, moreover, passes into a many-celled condition in the pre-
paration for spore-formation, for the points of the branches on which spore-
formation occurs, become shut oif into distinct cclls. Yide Unger, ‘Die
Pflanze in momente der Thierwerdung,’ (1843), and Thuret, ‘ Sur les Organes
locomoteurs des Spores des Algues,’ (‘Ann. des Sc. nat.,’ 1843.)

f Vide the section on Bryopsis, in Nägeli, (‘Algeusysteme,’ p. 171 ;)
‘On the Formation of Spores,’ J. Agardh, (‘Ann. des Sc. nat.,’ 1836.)

+ Vide Niigeli’s important researches in Caulerpa prolifera, (‘Zeitschr.
für Wiss. Bot.’) lieft 1, (1844,) p. 134.

§ Decaisne, ‘Plantes de l’Arabie lieureuse,’ ‘Arcli. du Mus.’ ii, (1839,)
t. vi, B.

9

130

THE PHENOMENON OF

which developes itself into the form of stein, root, and
leaf. The origin of organs of distinct kinds, whicli is
connected in the higher plants witli a very complicated
multiplicity in the cell-formation, appears here to be
attained simply by development of one and the same cell,
separatin g itself into different directions of growth.

The simplest plants witli a many-cellecl cycle of Vegeta-
tion, whether tliis be connected or broken up into con-
stituent members, stand far beliind the plants with a
unicellular cycle last considered, in regard to organic
differentiation. In tliis series again, nature ascends by a
scale of different types, from a minimmn of contrast in
growth, to a progressively more distinct realization of the
various directions of formation. That whicli was attained
in the former cascs through the differentiation of the
individual cell, without isolation of its parts one from
another, is here reaehed in the inost manifold gradations
through the formation of cells differing among themselves,
tliis happening either merely by a difference in the gene-
rations of cells, or by a different character of the cells of
the same generation. The distinctions occurring here
may relate either to the mode of origin of the cells
(combined or free formation), to the generative capability
(permanent cells and mother-cells), or to the mode of final
development (predominant growth in one or other direc-
tion, the different shaping of the contents and of the walls).
Thus arises an infinite variety in the genealogy, arrange-
ment and final development of cells, whicli becomes the
more difficult to trace the higher we ascend in the vege-
table kingdom. I confine myself to a few indications
from the lower groups of the vegetable kingdom, especially
from the Algse, the deep study of which appears the more
important the more fully the Science becomes conscious
of its object — to penetrate into the regulated course of
development of vegetable structures in all their infinite
complications.

The simplest conditions are exhibited by those plants
in which all the generations of cells, except the transition-

REJUVENESCENCE IN NATURE.

131

generation leading from one generation-cycle to another,
are alike. As long as mere vegetative multiplication
lasts, sirailar generations are formed ; with the commence-
raent of fructification is formed a last generation of cells,
different from the preceding, constituting at the sarne
time the first generation of the new cycle, and as such,
although originally different, exhibiting in its final develop-
ment the sarne characters as the sncceeding vegetative
generations. The last generation (that of tfie germ-cells
or spores,) is either imperceptibly or perceptibly different
from the foregoing, wliich circumstance gives room for
a series of subordinate gradations. Among the instances of
the former condition are the Chroococcaceae,* to which are
allied (with more intimate connection of the vegetative
generations of cells) the Oscillariese, and a part of the
Palmellaceae,! to which are related the Hormidia,\ with
Prasiola. In all these the propagative cells agree with
the vegetative in their origin, and are only distinguished
from them by the circumstance of becoming free at last,
while the vegetative cells of all or at least of several
immediately succeeding generations remain combined

* Vide Nägeli, ‘Einzellige Algen,’ p. 44, t. 1. In Synechococcus, Gleeothece
and Anhanothece the cells of all the generations become elongated and
divided in the same direction, and would, if they did not separate from eacli
other, form filaments, like Oscillaria ; in Merismopccdia the generations are
divided alternately in two direclions of a plane, whence flat, single-layered
plates are formed ; in Chroococcus, Glceocapsa, and Aphanoccipsa tlie division
takes place alternately in three directions of space, whence arise globular or
finaJljr shapeless families. Directing our attention to the diiference in the
Position of the axes and the planes of section of the cells, in the last-namcd
eases, we ma,y distinguish in the succession of the otherwise similar genera-
tions, subordinate cycles, in one case with two members, in the others with
three. flliere is also another rcspect in which the succeeding generations
are not always exactly alike, the last generations frequeutly remaining smaller
tlian the earlier, as, for example, is ordinarily tlie case in Glceocapsa, wliere
the size of the cells diminishes with the increasing magnitude of the family-
stock ( phytodom ).

t hx.yr. Slichococcus, (Näg., 1. c., t. iii, g); Uormospora, (Nag., t. iii, n) ;
Pleurococcus , (Näg., t. iv, e) ; Gbeocystis, (Näg., t. iv, r) ; PalmeÜa , (Näg.,
t. iv, d) ; Porphyridium (Näg., t. iv, ii); tlie first two forming rows of cells,
the last four solid groups of cells.

1 In the genuine Hormidia, not living in water, I have found no other
propagation out a breaking up of the filaments into single cells. Hcnce
Hormidium sccms to me most, closely allied to Stichococcus and Uormospora.

132

THE PHENOMENON OE

in families, either loosely (by thin or gelatinous enveloping
membranes), or more firraly (by tougher cell-coats). The
second case, in which the reproductive cells show impor-
tant differences from the vegetative generations, is repre-
sented by a few Palmellacese with swarming transitional
generations, and by the Diatomaceae. In the former the
reproductive cells originate, like their preclecessors, by
division, but they soon assiune a peculiar form and, fur-
nished with cilia, break through the enveloping membrane
of the old family to commence the vegetative cycle anew,
after a short period of motion -* in the latter, the
Diatomaceae, the transitional generation is formed in a
way essentially different from the preceding division -
generations, for two cells become connected by simple
or double conjugation, and, form one or two reproductive
cells by the combination of their contents at the point, of
connection ; these reproductive cells are originally globular
and altogethcr unlike the very peculiarly shaped vegeta-
tive cells of tliis family, but, by an uninterrupted growth,
soon acquire the shape of the parent-cells, from which
the first generation of the new cycle originating in tliis
way is distinguished merely by great er size.f

* Yide the genera Tetraspora , (Nüg., t. ii, c) ; Dictyosphmnum, (Näg.,
t. ii, e) ; Apiocystis, (Näg., t. ii, a) ; the first of which forms a cellular
plate, the second a free solid group of cells, the third a solid group attached
by an atteuuated base like a stalk. Besides the alternation in the direction
oi' the divisions, there occurs in these genera a further sliglit distinction in
the generation of cells, in tliat one or two generations of cells are alternately
transitory, tliat is, they divide anew before they have attained the usual size
of the vegetative cells.

f Vide Tkwaite’s * Observations on the Diatomaceae,1 ‘Ami. and Mag. of
Nat. Hist.,’ vol. xx, (1847,) t. iv ; ( Eunotia turyida), t. xxii ; ( Cocconema
lanceolatum, Gomplionema minutis&imum Himantidium pectinale), series 2,
vol. i, (1848,) t. xi, ( Melosira and Cyclotella .) The Denomination of the
reproduction cells produced through conjugation as sporangia (sporangial
frustules) by Thwaites, depends on a too widely stretched comparison with
those of the Desmidiacese. According to Thwaites’s own description, the
reproductive cells of the Diatomaceae pass directly into vegetative cells,
which is not the case in the Desmidiacese. The stränge phenornenon tliat
the primary generation formed through the conjugation attains about double
the size of the parent cells, is simply explained by a gradual decreaseof size
in the series of vegetative generations formed by division, a phenornenon to
which 1 have already callcd attention above in the case of Glceocapsa.

REJUVENESCENCE IN NATURE.

133

In the cases hitherto examined we could observe, in
the series of successive generations of cells, only one
different from the rest, the transitional generation, whicli
is at once the last of the old and the first of the new
cycle of generations. In the Desmidiaceae, the Zygne-
macem, and in Palmoglcea , the transitional generation
is divided into a double one, since the last generation
does not pass directly into the first, but the first
generation of the succeeding cycle is produced, as a
new structure, in the gerraination ; so that we liave
here to distinguish three kinds of generation of
cells, — the commencing generation, the concluding
generation, and the intermediate vegetative generations.
In the Desmidiaceae, after a long series of vegetative
generations of cells, which sometimes remain connected
in rows (. Desmidium , Didymoprium , Hyalotheca ), some-
times vegetate as completely separate cells (. Micrasterias ,
Euastrum , Closterium, &c.), there occurs a conjugation of
two cells and Union of their contents in the point of
connection, whence is formed one,* or, more rarely (by
double conjugation), twot reproductive cells, wholly
different from the preceding vegetative generations in the
form and aspect of the cells. They are always globular
and thick-coated, sometimes smooth,| sometimes rough,
like the ancient spiked mace-heads, with simple or many-
pointed, forked or hooked spines;§ and they do not
pass, like the swarming-cells of the Palmellacese and
the reproductive cells of the Diatomaceae, directly and by
uninterrupted growth into the primary generation of the
new vegetative series, but persist for a long time in a
condition of rest, during which, excepting as regards

* Viele the illustrations in Ralfs’ excellent Monograph of the British
Desmidiacea:, (London, 1848), for instance, t. iii, (. Didymoprium ) ; t. xvi,
(Comarium) ; t. xxiv, (Tetmemorus) ; t. xxv, ( Penium ); t. xxvi, (Docidium) ;
t. xxvii, xxviii, ( Closterium ); also Nägeli, ‘Einzell. Algen.,’ t. vii, f. 6,
{Comarium rupestre ).

t Ralfs, 1. c., t. xxx, {Closterium lineatum).

% Ralfs, 1. c., t. iv, {Desmidium) ; t. xxv, {Penium) ; t. xxix, {Closternm), &c.

§ Ralfs, 1. c., t. vii, ( Micrasterias ) ; t. xii, {Euastrum) ; t. xvi, {Cosmarium) ;
t. xxii, (Phycas/rum), &c.

134

THE PtlENOMENON OF

imperceptible internal processes, they remain wholly
unchanged.

To distinguish these from the direct germ-cells ( gonidia ),
I sliall call tliem seed-cells (spores).* The development
of tliese spores lias not yet been observed, but it may be
assumed as certain that they do not pass, as such, into
the primary generation, but produce this at the period
of germination by an internal transformation of their
contents, and bring these to light as a new generation,
witli a dehiscence of the old envelope. Certain early
conditions observed in Closterium and Euastrum, namely,
families of unusually small individuals, enclosed in
transparent, colourless vesicles,f render it even probable
that in certain genera of this family, a number of indi-
viduals are produced from one spore, by a formation of
transitory generations occurring already within the spore.
The enclosing vesicle is probably the dissolved and
swollcn-up internal cell-coat of the spore, which holds
the young individuals combined for some time after the
outer coat of the spore has been thrown off. The be-
haviour of the spores of the family of the Zygneinaceae,
which appears to be closely allied to that of the Desmi-
diaceae, confirms the conjecture as to the development of
the spores ofthelatter. The filaments of the Zygnemacese
are coraposed, like tliose of the Desmidiacese with con-
nected cell-gcnerations, merely of one kind of vegetative
cells, which increase by repeated halving.J The last

* Many autkors call tliese cells sporangia; but if we compare tbeir
behaviour with that of the spores of the higher Orders of Cryptogamia, in
which, in like manner, only the internal substance is developed into the
germ-plant, the coat bcing thrown aside, we must regard tliem as true
spores, wliile, on the othcr liand, tliose spores of the Algai passing directly
into germination, to which belong in particular all swarming-spores, differ
importantly from ordinary spores, and would be bettcr termed Gonidia.

•j- Yide Ralfs, 1. c. t. xxvii, and hocke, ‘Physiologische Studien/ (1847,)
t. iii, fig. 27.

% So far as my obseryations extend, the Glauients of the Zygnemacese
appear, like tliose of Desmidüm, to be formed merely by repeated division
into equivalent cells, tlius to possess ncither apical growth nor distinction
into an upper and lower end. I have never found the radieal structure by
which they are often attached otherwisc than lateral. Unfortunately I

RF.JUVENESCENCE IN NATURE.

135

cells originating in tliis way are ordinarily shorter tlmn
tliose of the earlier generations, and enter into conju-
gation* in the well-known way, subject to many
raodifications. Throngh the union of the contents of the
two conjngated cells, is formed, either in one of the two
cells, or in the link connecting them, a globular or longish
smooth spore, clothed with a multiple coat, from which
the young plant is developed after a long stage of rest.
In Spirogyra the coats of the seed-cell (spore) are thus
torn, — first the outer, thinner, water-clear coat, next the
inner, thicker, yellowish spore-coat is stripped ofi‘, and
the contents, transformed into the germ-cell and clothed
with a new coat, emerge in the form of a spindle-shaped
body, having both ends of like character,f which bears
great resemblance to the solitarily living cells of the
Desmidiaceous genus Spirotcenia. J But the observations
of Thwaites, who saw the contents of the ripe spore
separate into four portions in certain Zygnemacese, par-
ticularly Mesocarpus and Staurocarpus ,§ testify that a
formation of several germ- cells or young plants in one
spore may occur in tliis family.

Essentially different from the conditions of the
Desmidiacese and Zygnemaceae is the propagation of
Palmoglcea , a genus which has liitherto been reckoned
among the Palmellaceae, to which, although the occur-
rence of a conjugation ofthe cells mightincline one to the
opposite view, it is certainly more intimately related

liave not been able to follow the Observation of the germinating plant as far
as^ the commencement of root-formation. (See Pringsheim, on Spirogyra,
‘ Flora,’ 1852 ; Transl. in ‘Anrials of Nat. Hist.,’ 2d ser., vol. xi, 210. — A. H.)

* Vide Hassall, ‘ British Fresh-watcr Algse,’ (1845) t. xviii — xlix.

t The germination of the Spirogyra was observed by Yaucher (‘ Hist,
des Conlerves d’eau douce,’ 1803). I have seen it take place in the above-
described way in July of the present year, in Spirogyra retiformis , which had
been collected with ripe spores eleven inonths previously. I shall mention
hereafter some of the remarkable changes in the contents of the spores
occurring as preparatory to germination. (See Pringsheim, 1. c. — A. H.)

X Vide Ralfs, 1. e., t.xxxiv, f. 1,2.

§ 1 am only acqnainted with tliese observations from the report in the
‘ Botanische Zeitung,’ 1846, p. 498. (‘ Ann. Nat. Hist.,’ xvii, 262. See on
tliis subject also Pringsheim on Spirogyra, 1. c., p. 296. — A. H.)

136

THE PliENOMENON OF

than to the Desmidiaceae. While, in the Desmidiaceae
and Zygnemaceae, the last generation of vegetative cells
produces the seed-cells (spores) as a new generation,
since the latter shape themselves out free in the interior
of the conjugated parent-cells, through the loosenin g of
the contents of the latter from the walls, — in Palmpglcea
the last vegetative generation passes directly into the
formation of seed-cells (spores), since the cells cornbining
in pairs by conjugation, enter into perfect union, i. e.,
not merely mix tlieir contents in a new structure, but
merge or flow one into another entirely (coat and con-
tents) like two drops of water. The large seed-cells
(spores) originatmg in tliis way gradually acquire a thick
coat and oily contents, passing into a summer-sleep,
overl astin g the hot and dry season, tili, with the recur-
rence of the cold damp season, the contents become
inetamorphosed and divided, while the coat of the seed-
cell swells up and dissolves into jelly. Tlius the primary
vegetative generation is prodnced as a new generation
out of the seed-cell, the contents first formed by biending,
dividing again, and becoming freed from the coat of the
mother-cell.*

So far as wc lmve hitherto examined the differentiation
connected with the succession of generations of the cells,
we lmve found solely like cells within eacli generation ;
we lmve seen, morcover, all the terminal links of the
multiplied series attain the conclusion of the cycle (as
fructification-cells) in the same way, accidental exceptions
being of course excluded. The further complications
arise not only from a greater difterence presenting itself
in the successive generations, but from the cells of the
same generation also exhibiting different characters.
The latter, again, nmy happen in two ways : either two
daughter-cells originating in one and the same mother-
cell (therefore two sister-cells) are unlike eacli other,
or the daughter-cells of distinct mother-cells belonging to

* Yide the ügures in PI. 1, and the more minutc description of Palmogleea
in the Appendix.

11EJUVENESCENCE IN NATURE.

137

the same generation (tliat is the first-cousin-cells) differ
from eacli otlier. The first condition is of especial im-
portance in regard to the development of the organic
differences in vegetative structure, since on it depends
the apical growth and the rainification of many-celled
plants ; on the latter depends, among other things, a
duplicity of fructification, occurring even in the lowest
groups of the Yegetable kingdom, and which we shall
here, in the first place, briefly examine. Numerous
Algae produce two (or sometimes even three) kinds of
reproductive cells, either two kinds of moving or motion-
less gonidia, or gonidia and spores, or, lastly, two kinds
of spores, which last can also occur in the higher groups
of the Cryptogamia. Probably this phenomenon is more
generally diffused among the Algae than can be accurately
demonstrated at present ; therefore when I mention many
doubtful cases here, it is witli the express purpose of
directing attention to an object deserving of further
investigation.

Among the examples of plants with two kinds of moving
germ-cells, large ( macrocjonidia ) and small ( microgonidia )
the Water-net ( Hydrodidyon ) already mentioned above,
is especially worthy of mention. The unicellular indi-
viduals of this Alga, hitherto incorrectly arranged with
the Zygnemacese,* are United in their earliest stages into a
colony, forming a bag-shaped net. All the cells of such a
net are sister-cells, for they all originate in one and the
same mother-cell, but they clo not all behave alike when
fructification commences. In certain cells are formed
somewhat larger and less numerous gonidia (according to
the size of the mother-cell, 7000 to 20,000), in other cells
of the same net somewhat smaller and more numerous
gonidia (30,000 to 100,000). Only the former (the
macrogonidia) forma new net, which they doafter a short
trernulous movement (lasting about half an hour), without
leaving the mother-cell, by uniting together into a
daughter-net, which is gradually setfree by the solution of

* Kützing, ‘ Species Algarum’ (18d'9), p. 448.

138

THE PHIiNOMENON OE

the coat of the motlier-cell. The microgonidia, on the
other hand, distinguished not only by their smaller size
but by a longer shape, a small parietal red vesicle and
four long cilia (which appear to be very short in the net
forming macrogonidia), swarm out from the bursting
mother-cells, uiove about very actively, often for the
space of three hours, and after coming to rest, become
green Protococcus- like globules, which vegetate for some
time and at length die away without any further pro-
pagation. Tlius we see here formed in previously
indistinguishable sister-cells of the same net, brood-cells
of two kinds, which are both direct germ-cells or gonidia,
but are dcveloped one into a fertile generation, the other
into a sterile generation fated to destruction ; both active,
but in different degrees, one, moving for a short time,
forming a net, the others, “ swarmers,” never reunited
into acolony.* Two kinds of active germ-cells, (nmero-
gonidia and microgonidia, occur also in Cklamidococcus
pluvialis ( Ilamalococcus pluvialis, Flotowf ) a plant allied
to Chlamidomonas and the Volvocineae, into the cornpli-
cated history of which, however, 1 cannot enter further
here, lest 1 should be led away too far into the dcbateable
ground between the Animal and Vegetable kingdoms.
Another example, belonging to the group of the filiform
and branched fresh-water Algse, is furnished by Drapar-
neddia, from which Stigeoclonium is scarcely generically
distinct. Draparnaldia mutabilis, the numerous species
of Stigeoclonium, as well as the very nearly related
Chatophorce, are among those plants in which the for-
mation and birth of active germ-cells may -be most
easily observed, and indeed lmve very frequently been

* 1 must reserve tlie history of tliis rcinarkable plant, to which I sliall
return several times, for another opportunity. My own observations were
chiefly made in the summer of 1846, and the rcsults made known at the
meeting of the Swiss “ Naturforschcnde Gesellschaft,” at Schaffliausen, m

AlfU( Nova1 Act. Nat. Cur.,’ vol. xx, ii, 1844. (Also Colin, ‘ Nova Acta,’
xxii, p. 397, an abstract of which paper is xncluded m this volume. Also
Schacht, ‘ Die Pflanzenzelle,’ Berlin, 1852, p. 124. A. 11.)

REJUVENESCENCE IN NATURE.

139

examined.* In the three genera naraed tkere is formed,
in each cell of the branches, after their last vegetative
division, an active germ-cell, which, furnished with four
cilia and a parietal red vesicle, breaks through the side
of the cell-wall in swarming out. In Stigeoclonium
jorotensum, K. (?), however, I have found, towards the
end of the period in which this plant appears, a modifi-
cation of the mode of formation of the active gonidia,
in which each cell gave birth not to one, but (by per-
pendicular division of the contents) two to four smaller,
rnore roundish swarmers ; as to the germinative powers
of which, however, I have no experience. In Draparnaldia
mutabilis , also, I observed an analogous formation of
microgonidia, not produced by perpendicular, but by
further continued horizontal division of the cells.
Nägelif mentions an observation on Melosira varians,
according to which the parietal colour-vesicles of this
Diatomacean sometimes become detached, and move in
the manner of swarm-cells, which might indicate an
occurrence of active microgonidia, together with the above-
described formation of larger, motionless germ-cells.
Many examples may be cited of the conjoined occmTence
of gonidia and true spores; many of these, however,
still require more accurate investigation. In the family
just named, the Diatomacese, certain genera seem to
exhibit, as a second mode of reproduction, a formation of
seed-cells with numerous young individuals, such as we
have assumed above of Closterium ; so also Schizonema and
Micromega.X I*1 the Desmidiacese, on the contrary, a

* yide Treviranus, ‘Verm. Schriften/ ii, 1, p. 73 (1817— Draparnaldia) ;
Kützing ‘über die Verwandlung der Infusorien in niedere Algen-formen’
(1844 — Stigeoclonium stellare)-, Fresenius, ‘ Zur Controverse über die Ver-
wandlung von Infusorien in Algen’ (1847 — Choetophora). I have myself
observed the active germ-cells of Draparnaldia mutabilis, Sligeoclonium
thermale (June 1847), subspinosum (May 1847), protensum ? (May 1848),
(July 1849), Chcetophora tuberculata (Aug. 1847), and clegans (Sept.

t Vide Nägeli, ‘Gatt, einzelliger Algen/ p. 10.

I Vide Kützing, ‘die Kieselschaligen Bacillarien oder Diatomaceen’
(1844), t. xxv, f. 8 ; t. xxvii, f. 11 ; t. xxviii, f. 1.

140

THE PHENOMENON OF

formation of gonidia seems to occur sometimes together
with the spore-formation, and this in a double way. The
formation of numerous small swarmers in unconjugated
cells is mentioned by Ralfs as a not uncommon phe-
nomenon, butin so indistinct a way, that we cannot form
a satisfactory idea of it.* * * §

The active corpuscles found by Ehrenberg in a
Closterium, which he described as monad-like Infusorial
animalcules, under the narae of Bodo viridis, f might be
referred here.

According to Morren,:}: there is a totally different
proccss in Closterium Lumda, where, through conjugation
of two individuals, a single large active germ-cell is
formed, which coinmences a revolving movement in the
connccting canal of the parent-cell, already inside the
coats, then leaves the torn coats, and, after swarming
from teil to twenty minutes, sinks down and immediately
germinates, i. e., becomes elongated and returns to the
form of the old Closterium.

If these Statements of Morren are correct, there occnrs
in the Closteria a double character of the reproductive cells
formed through conjugation, these sometimes appearing
as direct genn-cells (gonidia), and sometimes as trueseed-
cells, it being uncertain whether the two cases occur in
one and the same species, or separately in different
species. § The two-fold fructification of Vauchcria has
been spoken of already above (p. 128); it follows also,
from the observations of J. Agardh,|| that large spores
are formed in addition to the small gonidia in Bryopsis.
Moreover, the simultaneous occurrence of gonidia and
spores is beyond doubt, in the large genus (Edoyonium

* Ralfs, ‘the British Desmidiem, p. 9.

+ Ehrenberg, ‘ Infusionsthiercheu,’ t. ii, f. 15.

1 Morren, ‘Memoire sur les Closteries.’ (‘Ann. des Sc. nat.,’ v, 1836.)
(See also Smith, ‘Ann. Nat. Hist.,’ 2d ser., vol. v, 1.— A. H.)

§ It is remarkable that Rall's, who has seen the formation of spores in so
many Desmidiacem, says nothing about it in reference to this very Closterium
Lunula, and the allied species CI. Mrenbergii and moniliferum .

|| J. Agardh, ‘Algic maris mediterrane? (1842), p. 4.

REJUVENESCENCE IN NATURE.

141

and the allied genus Bulboclicete , in which particular
cells, in (Edogonium those of the unbranched filament, in
BulbocJuete those of the branches, swell up and produce
within a motionless seed-cell, acquiring a special raem-
brane, often quite removed from the merabrane of the
mother-cell, and destined to a long stage of sleep, while
the contents of the rest of the cells, when otherwise
snfficiently abundant in quantity, become converted into
an active gerrn-cell, bearing a crown of. numerous cilia.
In (Edogonium the birth of the swarming-cell takes place
through a transverse dehiscence of the parent-cell at the
anterior end • in Bulbocluste by disarticulation of the
small cell bearing the bristle, and rupture of the wall
separatin g it from that of the large cell.* Certain species
of (Edogonium {(E. echinospermum and apophgsatum ) are
especially remarkable, since they produce, in addition,
two kinds of swarming cells, macrogoniclia and microgo-
nidia, the latter of which originate in special, very short
cells, arranged mostly in groups between the larger
cells. The macrogonidia germinate as soon as they come
to rest, and grow up into normal filaments ; but the
microgonidia, although they germinate, produce only
two-celled dwarfs, which die away without developing any
further. The genus Coleochcete f affords another example
of the united occurrence of gonidia and spores. Indi-
vidual terminal cells of this genus are developed into

* In (Edogoniicm fonticola A. Br. (‘Kg. Sp. Alg.,’ p. 368), a species wliicli
occurs almost everywhere in the pools formed by running springs, the forma-
tion of the “ swarmers” may be observed throughout the whole year, while
the formation of the restiug spores occurs but rarely. In OS. capillare,
the commonest species of the genus, I have hitherto met with “ swarmers”
alone. I have observed both kinds of fructification iu OS. Landsboroughii
(Hass.), vesicutum (Yauch ,),f((scialum (Hass.), Braunii, Kg., echinospermum,
A. Br. (Kg. 1. c. 366), apophgsatum, A. Br. (ibid.), BulbocJuete seligem, Ag.,
and minor, A. Br. (Kg. 1. c. 422). Ogmatonema confervaceum, Kg. (Sp. Alg.
375), behaves exactly like QSdogonium in the burstingof the cells, but I have
not yet succeeded in observing the swarming out. (See also Thuret,
‘ Zoospores des Algues,’ Anu. des Sc. nat., 3d ser., xiv, p. 17, pl. 19. — A.H.)

f Vide Nägeli, ‘ Algensysteme, ’ p. 166, v, f. 22 — 31. I have observed
the formation of spores, as well as of gonidia, in both species of this genus
C. scutala, Brib., and pulvinata, A. Br. (Kg. * Sp. Alg.,’ 424).

142

THE PHENOMENON OF

sporangia, in which several resting spores are formed by
division of the coat lining tbe wall, while tlie contents of
the rest of the cells are frequently converted into a
gonidium , which in C. scutata breaks througli the upper
wall of the cell, and in C. pulvinata emerges laterally, to
swarm. The gonidia of this genus appear to possess
only two cilia. In the marine Algae of the genera
Mesoglcea* * * § and Myrionema , a double, in Ectocarpus\
a triple, fructification has been observed ; but it is very
doubtful whether large resting spores occur in these
genera, besides active gonidia, since Nägeli has pointed
out that in Ectocarpus the contents divide into numerous
small germ-cells, not only in the roundish apical cells of
the branches, but in the longish, many-celled points of
the branches, and in the cxpanding articulation cells of
the stcm. On the other lmnd, in the Fucoideae, (in the
strictest sense,) the occurrence of large resting-cells,
together witli very small swarming-cells, regarded by
Decaisne and ThuretJ as spermatozoids, is beyond doubt.
Both kinds of fructification are formed, in the Fucoideae,
in the terminal cells of the jointed filaments which clothe
the interior of the fructification cavities. The extremcly
small gonidia are of pale colour, and have a parietal red
point. According to the authors cited, they exhibit two
extremely delicate filaments, one in front vibratile, the
other, behind, said to be passively swayed about. \ The

* Kiitzing, ‘ Phyc. generalis/ t. xxvii, 1.

f Vidc Crouan (‘ Ann. des Sc. nat./ 1839, p. 218, t. v); and Nägeli,
‘ Algeusysteme/ p. 145, t. ii, f. 1 — 6. (Also Tliuret, ‘Ann. des Sc. nat.,’
3 ser., xiv, p. 25, pl. 24. — A. II.)

X Decaisne ct Thuret, ‘ Reckerchcs sur les Antlieridies et spores des
Fucus/ (‘Ann. des Sc. nat. i, iii, 1845,) t. i— ii.

§ The position of the cilia is thus importantly different from that usual in
the active gonidia of the fresh-water Algse ; on the other hand, the swarming-
cells of the Fucoidem do not agree at all in form witli the spermatozoids
such as we are acquainted with in the Characeoe, Mosses, and Ferns.
Whether, like the spermatozoids, they are formed in special, minute cellules,
or originate by simple division of the contents of the large parent cells, is
unfortunately unknown. The character of the contents ot the “ swarmers”
of the Fucoidese renders it unlikely that they possess the power of germi-
nating, but it cannotbe deduced from this that they havea l'ertilising action.

REJÜVENESCENCE IN NATURE.

143

larger spores, on the contrary, exhibit a strong mem-
brane and dark olive-brown contents. After they are
sown the membrane swells up, and the contents become
divided, at least in some genera of the Fucoidese, into
two, four, or eight parts, which pass at oncc into germi-
nation, a process which reminds us of the above-described
behaviour of the spores of the Closteria and certain
Zygnemacese. As a last example of the occurrence of
double fructification in the group of Algse, I mention
Chantransia. The ordinary, long-known fructification of
this genus consists of globular, very thin coated germ-
cells, having a central rose-coloured vesicle in the light
verdigris green contents, which germ-cells are formed
separately in the terminal cells of the tufted lateral
branchlets, and are set free by the rupture of the parent-
cells. They have no independent motion, but probably
germinate directly after they are discharged ; on this
point, however, we have no certain observations. In
the same plant, and indeed on the same “Stocks” and
branches, there occurs more rarely a second kind of
fructification,* in which the cells forming the links of
the branches swell strongly at the side, and form a large
thick-coated spore in the protruberance, which becomes
shut off as a distinct cell.

Chantransia therefore exhibits two kinds of motionless
reproductive cells, the smaller of which are probably
immediately-germinating gonidia, the larger resting

The decision of their true import therefore requires, on the one hand, fur-
ther observations completing the history of their formation and life; and, on
the other, the discussion of the question, whether the formation of active,
and, as we have seen, in many cases sterile gonidia, is not to be regarded
as a precursor of the formation of spermatozoids, just as in a higher group,
the formation of two kinds of spores, the former of which are likewise, in
many cases, sterile, must bc regarded as an anticipation of the contrast of pollen
and embryo-sac. (See Thuret, ‘ Comptcs Rendus,’ April 25, 1853 ; Transl.
in ‘Annals of Nat. History,’ 2d ser., vol. xii, p. 64, who shows tliat the
antherozoids do fecundate the spores of Fucoidese. — A. H.)
i * I observed this in Oetober of last year in a form of Chantransia clialybea,
l’rics, very frequent at Freiburg, which Kützing (‘ Sp. Alg.,’ 430) mentions
as Ch. clialybea , var. radians.

144

THE PHENOMENON OE

spores. Two kinds of thick-coated and resting spores,
macrospores and microspores, which are bot.h fotind in
the same way, in fours in mother-cells, occnr, lastly, in
many Lycopodiaceae,* in the allied genus Isoetes, f and in
the genera of the Rhizocarpese, Marsilia, Pilularia, and
Scilvinia. In the exaraples last named we have advanced
very far beyond the original simplicity of the vegetable
structure which we had before ns in the first examples ;
they only admit of citation here, in so far that they like-
wise exhibit essentially similar generative series of mother-
cells, and finally go out into distinction of fructification
cells.J

In the higher groups of the Vegetable kingdom, the
difference of the fructification-cells is preceded by a still
more important difference of the vegetative generations of
cells. The distinctly qualitatively differenced reproductive
cells(fertilizing-cellsand germ-cells) form the conclusionnot
of similar, but ofunlike series of generations of cells, and,
moreover, not of all, but only of certain series of generations,
while a still greater number of series attain their purpose
and destination within the vegetative organism, without
arriving at fructification in the last generation. While
in the lowest plants, all vegetative cells, as mere repe-
titions of the same thing, belong to one rank, in the
higher the cells divide, in the course of the generations,
into different ranks, by which the organism is completed
on a different side, and through which is caused a more
necessary coherence and more intimate combination than

* Göppert concludes tliat both the small and large spores are capable of
gennination, from observation of two different forms of the young plants in
Selaginella denticulatu. (‘Ucbersicht der Arbeiten der Schles. Ges. für
Yaterl. Cultur.,’ 1845, p. 129.) (Proved incorrect. — A. H.)

f According to a recent note in a letter from Dr. Mettenius (Nov. 1844),
spermatozoids are dcveloped in the small spores during the gennination of
the large spores, which confirms the analogous observation of Nägeli on
Pilularia. Zeitschr.,’ 1846, 188.)

x (On tliis subject, much developed since the above was wntten, consult
the Report on the Higher Cryptogamia, by A. Henfrey, in the ‘Aunals of
Nat. History,’ 2d ser., ix, 441, which also gives most of the new literature
of this subject. — A. H.)

REJUVENESCENOE IN NATURE.

145

we have seen in the lower stages, where each cell strives
to vegetate for itself alone. The development of different
ranks of cells, with wliich is connected the realisation ot
the organic differences in the vegetative sphere, in the
higher plants, is chiefly attained by the above-mentioned
production of daughter-cells of different kinds in one and
the same mother-cell, therefore by differing sister-cells.
We will examine this condition in a few examples of the
simplest kind, so as to indicate the patli by which natnre
advances in the production of the multiplicity of cell-
formation of one and the same plant.

We meet with the first Separation of vegetative per-
manent cells from series of generations terminating in
reproductive cells, in the Nostoc-like Algae. The
necklace-like filaments of Nostoc, composed of a row
of cells, exhibit at one or both ends, as also here and
there in the course of the filament, particular cells
distinguished from the rest by size, regulär rounding,
thick membrane, and pale, homogeneous contents ;
while the remaining, smaller, thin-coated cells, filled with
darker and offen granulär contents, continue to multiply
in rapid succession by division, until they finally, in the
last generation, fall apart as germ-cells, exhibiting no
perceptible difference from the preceding generations.
The large terminal and interstitial cells just named
remaiu almost unchanged, neither undergoing further
vegetative division, nor taking part in the propagation.*

The origin of these peculiar boundary-cells can only
take place by certain of the cells dividing into two unlike
daughter-cells, one of which becomes a vegetative per-
manent cell, the other a mother-cell of a series of uniform
generations of cells, terminating in fructification. It is
probable that the very first cell (the germ-cell) divides in
this way into two unlike cells, f andthen, when a filament

* These cells liave been hitherto incorrectly regarded as seed-cells,
( spermalia , Kg.).

t Very young plants of Nostoc (or Eormosiphon ?), exhibited a short fila-
ment enclosed by a gelatinous vcsicle, having a boundary-cell only on one
side, and this lying outside the gelatinous vcsicle.

10

146

THE PHENÖMENON OF

lms beeil formed, this must be repeated, but in the
reverse direction, by the cell at the opposite end, as well
as by certain otliers lying in the midst of the filament.
This first division into two unlike cells may be regarded
as the rudimen t of an apical growtli, which, however, is
arrested at the first stqp, since, after the production of a
single cell of the second Order, the further division of the
cell of the first order of the second degree (the apical
cell), produces merely cells of the first order. Anabaina
(to which may be addcd SpJuerozyya and iSpermosira *)
and Cylin drosperm um are distinguished from Nostoc by
the occurrencc not merely of two, but of three modifi-
cations of cells, since the cells multiplying by continued
division (the cells of the first order) do not all behavc
alike in the last generation, but partlyexpand intolarger,
thick-coated seed-cells, doubtless destined to a long
period of rest, and partly remain small and thin-coated,
and then perhaps perform the function of a second kind
of reproductive cells, corresponding to the more gonidium-
like gcrm-cells of Nostoc , but, perhaps, at least in many
cases, die away as sterile cells, when the filament breaks
up. In Anabaina several of the intermediate cells of
each section are developed into the larger seed-cells ;
in Cylindrospcrmum the lateral cells immediately bound-
ing the terminal or interstitial cells.

The filaments of the Nostochinese exhibit, otherwise, no
perceptible contrast at the two extremities, and their in-
tertwined and irregulär position admits of no distinetion
into an upper and lower end.f In the group of the
Scytonemese and llivulariete (excluding the Masticho-
trichese) a contrast of this kind is distinctly present, but
still without any root-like formation of the lower end,

* These three genera are so loosely defined by Kützing, that \ve cannot
form any clear idea of bis distinctions, Anabaina seems to me to be only
sterile Splicrozyga, and Spermosiru to difl'er merely by sborter and more dis-
coid cells, and Nodularia may be a sterile condition of the last form.

f 1 found indications of such a contrast in Cylindrospermum liumicola, Kg.,
and other species, in which one end decidedly comes to its full development
later than the other.

REJUVENESCENCE IN NATURE.

147

which is formed by a vegetative permanent-cell, like the
boundary cell of Nostoc. In Tolpothrix and Schizosiphon
several such vegetative permanent-cells frequently occur
at the base of the filament, and in tliese very genera, as in
Scytonema and TJuactis, the formation of theni is repeated
at intervals in the coiirse of the filament, where they
appear as interstitial cells, which by subsequent parting
of the filament, and the lower part overgrowing the
upper, become basilar-cells of seerning branches. In the
Scytonemeae, the filaments are of pretty uniform structure
throughout the whole length, but in the Rivularieae they
run ont above into a more slender capillary point or
flagellum. It is not yet made out whether the distinction
of the upper and lower end of the filament of the Algse
of this group is caused by an apical growth continued on
beyond the formation of the first basilar cells, but this
much is certain, that the cells of the filaments multiply,
in their further growth, as in the Nostochineae, by repeated
halving, which, however, does not terminate simultane-
ously in all parts of the filament, but continues longer in
some parts than in others. In the Scytonemeae it is
carried on farther in the points (not merely of the entire
filaments, but also in the individual sections).* In the
Rivulariaceous genera Masticlioth rix, Mastichonema, Rivii-
laria, &c., in the lower ; in Euactis, in the intermediate
parts. With this is associated a distinction of the cells
belonging to the different parts of the filament, becoming
continually more evident with the progress of the division,
and especially marked in the last generation. In the
Scytonemeae the cells pass into genn-cells, in the last
generation, mostly only at the upper part of the filament;
in Euadis only in the intermediate ; in Mastichothrix and
Mastichonema only in the lower, and thicker, not in the
upper capillary portions ; in Rivularia, lastly, the cells of
the lower thicker part exhibit another difference, for the

* Tn many species of Scytonema and Tolpethrix the lower end of the
scctions may grow out in this way into new points.

148

THE FHENOMENON OF

lowermost (adjoining the basilar permanent-cell) becomes
a large cylindrical, tliick-coated seed-cell, as in Cylindro-
spermum , wliile tlie following sh orter cells, richer in con-
tents, are perhaps to be regarded as a second kind of
germ-cell.*

From tliese examples of less decided and often still un-
settled contrast of growth in the rows of cells chained
together into filaments, let us direct our attention to cer-
tain others, in which the contrast of ascending and
descending growth becomes more evident, on the one side
by distinct root-formation, on the othcr by undoubted
terminal development of the row of cells (cell-forming
apical growth). Tliis condition is exhibited in the sim-
plest way, namely, by a filament-stem always single, in
Ulothrios and (Edogonium, two genera, otherwise very
different, which recent Algology has extracted from the
earlier chaos of Con ferne. TJlothrix zonata f has active
germ-cells, of which 8 — 10, or in weaker parts of the
filamcnt sometimes only four are formed in one rnother-
cell. These are of longish-ovate form, having four very
fine cilia at the anterior pale extremity, and a red vesicle
elongated in the trän sverse direction in the inferior, lying
at the side, about the middle. After swarming for at
most two hours, tliese germ-cells come to rest, and
immediately germinate. The cell t.hen becomes elongated
in two opposite directions, growing out in one, into a
slender, hyaline, simple (or bifurcated at the point) fixing-
root ; at the othcr, extending cylindrically, and forming
the commencement of a green filament-stem. Usually on
the second day the first cell divides into two, about in
the middle of the upper green end, and thus are produced
a lower root-bearing end, dividing no farther, and an
upper end which, after growing to not quite twice its

* It sometimes appeared to me as though the seed-cell, or the so-callcd
manubrium of Rivularia originated by re-fusion of several previously separate
cells, analogous to what occurs in Pulmoglcea; but I could not attain a com-
plete conviction of the truth ot this.

f Yide Kützing, ' Phyc. generalis’ (1843), t. lxxx. (Also Schacht, die
Pflanzenzelle,’ 1 842, p. 1 20. — A. II.)

REJUVENESCENCE IN NATURE.

149

original length, separates again into a posterior longer,
and an anterior shorter, cell ; which latter repeats the
same process, and so on. Thus, by a continually repeated
division of the apical cell into two unlike cells, is forraed
a series of cells of a second order, the link-cells of the
filament, the first of which is at the same time the root-
cell. The filaments of Ulothrix zonata , onceformed, grow
no more in thickness, but gradually increase in diameter,
from the base to the summit, in such a manner that the
anterior parts offen appear thrice or four times the diameter
of the posterior, lying nearer the root.* The root-cell,
as well as those next succeeding it, remain unaltered and
are infertile ; the following link-cells, on the contrary,
after they have attained a length about twice their
diameter, divide into two equivalent cells, consequently
into cells of the second generation of the second order,
whereby, since no further elongation takes place, cells are
produced of about equal length and breadth. Still farther
forward, therefore in the thicker part of the filament,
tliis division is repeated once or twice more, so as to give
rise to cells of the third or fourth generation of the second
order, the length of which is only \ or \ their diameter.
Finally, in the cells of the last generation of the second
order, the germ-cells are produced by division of the
contents alternately in the three directions of space.f
The filaments of (Edogonium , in their earlier development,
follow the same course as those of Ulothrix zonata , but
differ in the subsequent subordinate division of the
original link-cells, since these do not divide into equiva-
lent cells, but into unlike cells, forming series of link-cells
of the second degree, which is moreover accompanied by
a longitudinal extension of the subordinate link-cells.
The lowest link-cell, which expands at the base into a
discoid, often elongately lobed root-foot, and is always of

* Hence the great variability in tlie diameter of the filament, which
varies from to iä0> or sometimcs Tfoi millim.

f \ ide Nägeli, ‘Algcnsystcmc,’ p. ]37, t. i, f. 53, 54.

J 50

THE PHENOMENON OF

greater diameter, and more bellied out than the suc-
ceeding, is the only one which divides no more, and
constantly remains sterile. The resting spores of this
genus are formed in the swollen end-cells of the subor-
dinate rows of links.*

The Ramification , like the apical growth, of the many-
celled Algge, depends upon a division of the cell into two
unlike parts, one of vvhicli retains the character of the
mother-cell, and the other deviates ; while, however, in
apical growth the diffcring cell belongs to a higher Order
of cells, in ramification the differing cell returns, on the
contrary, to a lower order, since it becomes a cell of the
first degree of the first order, that is, the primary cell of
a new serics of generations.

Ramification is cxhibited in its simplcst form in Siro-
siphon ( Ilassallia ) and Ilaplosiphon. f Rarticular cells of
the rows which form the filament-stem of these Algae,
divide in the perpendicular direction into two unlike
cells, one of which, mostly larger, remains as a link-cell
of the principal filament, while the other, elongating in
the horizontal direction, emerges from the stem as a new
axis, and tlien divides again, at right angles to the new
axes, into two unlike cells, — a new apical cell, and a first
link-cell of the brauch. The further development of the
branch takes place, as in the principal axis, by repeatecl
division of the apical cell, which is followed subsequently
by a division of the link-cells. The ramification proceeds
in a different way in the Cladophorcc (the brancked Con-
fcrvac of the older authors), in which the branches, solitary,
or sometimes opposecl in pairs, sprout forth from the
upper margin of the link-cell, where a bagging out, as it
were a new laterally projecting apex of the cell, is first
formed, which, by division of the thns enlarged cell into
the old and new parts, becomes the first cell of the brauch.

* I am not acquainted witli any genus of Alga with simple fllaments
formed solely by cell-forming apical growth without subordinate division of
the link-cells. Arnong the ramified Algffi, Batrachospermum forms its stem
in this way.

{ Kützing, ‘ Spec. Alg.,’ p. 894.

REJUVENESCENCE IN NATURE.

151

The ramification in Chantransia, Bulbocluste, Chatophora,
and Coleocheete pulvinata, exhibits siinilar characters. In
the last two exaraples there occurs, in addition, a descend-
ing ramification from the lower margin of the link-cells ;
so tliat, in many cases, an ascending brauch springs
from the upper border, and a descending branch from
the lower border of the same cell. With the exception
of the reverse direction, the mode of origin of these
descending root-, or rather stolon-like branches, is the
same as that of the ascending.

A further series of very varied organic differences next
arises in the relations of the cell-formation of the branches
to the cell-formation of the stem. If the cell-formation
in the branches is limited, and the branches fall short
considerably in size of the stem, they admit of comparison
with leaves. Tims, for example, in Draparnaldia , in
which the branches mostly arising in pairs from one cell of
the stem, as well as the branchlets of the second Order
springing from these, are formed of mnch smaller cells
than the stem, the upper, larger, forming the hyaline
capillary points of the branches, while the lower and
shorter, abundantly furnished with green contents, pro-
duce within them the germ-cells. The large cells of the
stem of Draparnaldia are sterile vegetative-cells ; only
the apex of the long stem behaves in the same way as
the branches, and is, like them, fertile, and terminated by
a capillary point. In Batrachospermum, on the contrary,
the stem is unlimited in its growth, formed of a series of
link-cells, which originate through the repeated division
of a dome-shaped apical cell, and undergo no further
transverse division. From the upper border of the
young, still very short link-cells arise 5 — 6 radiately-
arranged projections, which are very early cut off, in the
shape of special cells, from the central cavity, which
remains as a link-cell, and these new cells then grow out,
by limited link-formation, into the small, again much
ramified branches, forming the peculiar globular whorls

154

THE PHENOMENON OF

stein, starting from uniform* or dissimilarf division in
the link-cells ; how, moreover, the vessels are formed in
the parenchyma of the stem in the vascular plants, i. <?.,
how their origin is connected witli the generative suc-
cession of the rest of the cells. J It must likewise be
demonstrated how the cell-formation in ’ the leaf, pro-
gressing according to fixed laws, produces the simple
cellular plate, such as is exhibited by most Mosses, and
the many-layered plate, with varied arrangement and
direction of the cells in the different layers, of the higher
plants ; how herc again the formation of the vascular
bundles enters iuto the tissue in the most diverse dis-
tribution, and how these vascular bundles are connected
in their origin with those of the stem. Finally, it must
be demonstrated how, beyond all the generations of
cells arriving at vegetative permanence and at their final
term in the graduated construction of the organism and
the contrast of its organs, certain series of generations,
withdrawing themselves from the vegetative termination,
finally attain their destination prepared, protected, and
supported by all the otlier series, in the formation of
reproductive cells.

We have here stated a problem, the solution of wliieli

* Vide Sti/ptocaulon, in ICiitzing’s ‘Phycol. generalis,’ t. xviii; in Lemunia
also, the formation of the compound tissne starfs from a simple row of link-
cells originating by horizontal division of an apical cell, which link-cells
divide first by a cross-wisc pcrpendicnlar Segmentation into four, tlien by
recurring horizontal division inr.o eiglit equal cells. In vvhat way the
Separation in the peripherical and central cells next takes place, and how the
division proceeds in the interior, it is not easy to determine; but the result
shows that the division occurring in the interior is far outstripped by that
in the peripherical cells, sincc a rind is formed outside composed of two
layers of very small cells, while the interior is occupied by many-times larger
cells, separating from one another in the centre, and forming a medullary
cavity.

f Yide Plilola (Kütz. ‘ Pliyc. general.,’ t. 46, vi) ; Naccaria (ibid., t. 44,
iv) ; Älsidiim HMminthochorton (ibid., t. 45, xi) ; Laurencia (Niigeli,
‘ Algensyst.,’ t. 8).

+ Unger’s treatise on the ‘Genesis of Spiral Vessels’ (Linnaea, 1841,
385, t. 5) shows that the so-called vessels of plants are only rows of cells of
peculiar kind. (Transl. in ‘ Ann. des Sc. nat.,’ 2d scr., t. xvii, p. 226. See
also Mohl, ‘Vorm. Schriften,’ 281 ; Schacht, ‘ Pflanzenzelle,’ 185.— A. II.)

REJUVENESCENCE IN NATURE.

155

still lies far away from us ; yet these observations may
serve to raake clear the importance of the cell as the
organ of the graduated self-determination and isolation of
life in all its formative movements, as the constantly
renewed point of Separation in growth advancing by suc-
cessive links, and to indicate how the subordinate sphere
of life of the cell is the more intimately interwoven in
the total ity of the organism, the more the specific vital
purpose separates into its factors.

Examining the individual cell more closely, we must,
in the first place, observe that the term cell does not
correspond exactly to that to which we especially apply
it, for we understand as cells not merely the membranous
vesicles or utricles which form the tissue, but also their
contents ; we apply the name cell not alone to the little
chamber formed by the completely closed-in wall, within
which the vegetable life conceals itself, but also to its
living inhabitant, the more or less fluid and inwardly
mobile body, which is bounded, within the chamber, by
its own more delicate coat (the primordial utricle). The
cell is thus a little organism, which forms its covering
outside, as the muscle, the snail, or the crab does its
shell. The contents enclosed by these envelopes form
the essential and original part of cell, in fact must be
regarded as a cell, before the covering is acquired. Erom
the contents issues all the physiological activity of the
cell, while the membrane is a product depositecl outside,
a secreted structure, which only passively shares the life,
forming the medium of intercourse between the interior
and the external world, at once separating and combining
the neighbouring cells, affording protection and solidity
to the individual cell in connection with the entire tissue.
Hence the development of the cell-coat, as a product of
cellular activity, always Stands in inverse proportion to
the physiological activity of the cell. In youth, thin,
soft, and extensible, the cell-coat allows abundant
nutrition and advancing growth ; subsequently thickened
and therewith hardencd by the dcposit of lamellee, it

156

THE PHENOMENON OF

compresses the contents within continually narrower
boundaries, more and more excludes intercourse with the
external worid, and puts a term to growth. Thus the
life of the plant builds its torab in the very cell — dies
away at last in its own work.

That the origin of the cell precedes its enclosure by
a cell-membrane, is shown most distinctly in those cases
in whicli the cell originates free, that is, vvithout contact
with the mother-cell, or where it becomes free by being
cxpelled iminediately after its production. The last
condition occurs in the swarm-cells, or active gonidia of
the Algae, which so long as the raotion lasts, possess no
cell-membrane separable from the contents, and must
bc regarded as bounded merely by the primordial utricle,
which is intimately connected with the contents. It is
well known that by the action of dilute acids or spirits of
wine, the contents of the cell are contracted and wholly
or partially removed from the cell-membrane, which thus
appears as a structure clearly separated from the contents.
The active gonidia of (Edogonium, Bulbochcete , Ulothrix,
Draparnaldia, Siigeoclonium , Chcetophora, Hydrodictyon ,
and other genera which 1 liave repeatedly examined in
reference to this point, contract, when so treated, entirely ,
without leaving a colourless mernbrane at the boundary
of the original dimensions, which does always occur after
germination has commenced. Thus the gonidia of
Ulothrix and Hydrodictyon exhibited a hyaline vesicle,
the contents of which were contracted on the application
of tincture of iodine, a few hours after they had come
to rest, on the same day that they were born. That
these gonidia possess another mernbrane, intimately con-
nected with the contents (the primordial utricle), is
testified by their smooth and exact outline, and further
by the phenomena which present themselves in the
solution frequently taking place soon after birth in weak
gonidia. In such cases the cell is seen to acquire a.
globular form and swellup; through absorption of water,
large hyaline cavities originate, displacing the contents,

REJUVENESCENCE IN NATURE.

157

except at a fevv points. The soon succeeding collapse
and dissolution of tlie cell is distinctly opposed for some
time by a membranous bounding-structure. In very large
gonidia, especially those of Vaucheria clavata, this mem-
brane exhibits considerable thickness, so as to be clearly
distinguishable as such, but in this very case it shows that
it possesses totally different properties frorn those of tlie
cell-membrane subsequently enveloping it : while the
cell-membrane, be it ever so delicate, appears tough
and extensible, the primordial utricle is found soft and
brittle, so that the slightest injury destroys its continuity,
which, however, takes place so as to seern rather a
Separation or flowing apart of the substance than a
tearing through.* It is this primordial utricle which
bears the numerous vibratile cilia clothing the whole
surface of the cell in Vaucheria , these appearing to be
formed out of the substance of the coat itself and mere
processes of it. lodine causes these cilia to contract to
a certain extent, and acquire a brownish-yellow colour,
which colour presents itself the more distinctly, the more
abundantly and closely the cilia are collected together,
as, after Vaucheria , is the case especially in OEdogonium
and Bulbochcete, where they form a dense crown of
cilia. The body of the germ-cell acquires a deep brown
colour with tincture of iodine ; the hyaline apex mostly
existing in the stage of motion, as well as the primordial
utricle, indistinguishable from the contents in small
swarming-cells, liave this colour, sometimes appearing a
little lighter. This colouring agrees with the well-known
behaviour of the primordial utricle of the cells of the
Phanerogamia.t The cilia disappear with the com-
menceinent of the rest, and before the formation of the
proper cell-membrane, not only in Vaucheria, but in all
Algse where the germ-cells have a ciliary motion of short

* So says Unger, ‘die Pflanze im Momente der Thierwerdung,5 1845,
p. 36.

+ Vide H. von Mohl, ‘ Botanische Zeitung,’ 1844, p. 276. (Transl. in
‘ Scientific Mcmoirs,’ vol. iv, p. 93. — A. H.)

156

THE PHENOMENON OF

compresses the contents within continually narrower
boundaries, more and more excludes intercourse with tlie
external world, and puts a term to growth. Thus the
life of the plant builds its tomb in the very cell — dies
away at last in its own work.

That the origin of the cell precedes its enclosure by
a cell-membrane, is shown most distinctly in those cases
in which the cell originates free, that is, without contact
with the mother-cell, or where it becomes free bv being
cxpelled innnediately after its production. The last
condition occurs in the swarm-cells, or active gonidia of
the Algm, which so long as the motion lasts, possess no
cell-membrane separable from the contents, and must
bc regarded as bounded merely by the primordial utricle,
which is intimately connected with the contents. 1t is
well known that by the action of dilute acids or spirits of
wine, the contents of the cell are contracted and wholly
or partially removed from the cell-membrane, which thus
appears as a structure clearly separated from the contents.
The active gonidia of ( Edogonium , Bulbochrcte, Ulothrix ,
Drajoarnaldia, Stiyeoclonium , Chcetophora, Hydrodictyon ,
and otlier genera which J liave repeatedly examined in
reference to this point, contract, when so treated, eniirely,
without leaving a colourless membrane at the boundary
of the original dimensions, which does always occur after
germination has commenced. Thus the gonidia of
Ulothrix and Hydrodictyon exhibited a hyaline vesicle,
the contents of which were contracted on the application
of tincture of iodine, a few liours after they had couie
to rest, on the saine day that they were born. That
these gonidia possess another membrane, intimately con-
nected with the contents (the primordial utricle), is
testified by their smootli and exact outline, and further
by the phenomena which present themselves in the
solution frequently taking place soon after birth in weak
gonidia. In such cases the cell is seen to acquire a
globular form and swellup; through absorption of water,
large hyaline cavities originate, displacing the contents,

REJUVENESCENCE IN NATURE.

157

except at a fevv points. The soon succeeding collapse
and dissolution of the cell is distinctly opposed for some
time by a membranous bonnding -structure. In very large
gonidia, especially those of Vaucheria clavata, this mem-
brane exhibits considerable thickness, so as to be clearly
distinguishable as such, but in this very case it shows that
it possesses totally different properties from those of the
cell-membrane subsequently enveloping it : while the
cell-membrane, be it ever so delicate, appears tough
and extensible, the primordial utricle is found soft and
brittle, so that the slightest injury destroys its continuity,
which, however, takes place so as to seern rather a
Separation or flowing apart of the substance than a
tearing through.* It is this primordial utricle which
bears the numerous vibratile cilia clothing the whole
surface of the cell in Vaucheria , these appearing to be
formed out of the substance of the coat itself and mere
processes of it. lodine causes these cilia to contract to
a certain extent, and acquire a brownish-yellow colour,
which colour presents itself the more distinctly, the more
abundantly and closely the cilia are collected together,
as, after Vaucheria , is the case especially in (Edogonium
and Bulbochate, where they form a dense crown of
cilia. The body of the germ-cell acquires a deep brown
colour with tincture of iodine ; the hyaline apex mostly
existing in the stage of motion, as well as the primordial
utricle, indistinguishable from the contents in small
swarming-cells, have this colour, sometimes appearing a
little lighter. This colouring agrees with the well-known
behaviour of the primordial utricle of the cells of the
Phanerogamia.t The cilia disappear with the com-
rnenceinent of the rest, and before the formation of the
proper cell-membrane, not only in Vaucheria , but in all
Algrn where the germ -cells have a ciliary motion of short

* So says Unger, ‘die Pflanze im Momente der Tliicrwerdung,’ 1845,
p. 36.

f Viele H. von Mohl, ‘Botanische Zeitung,’ 1844, p. 276. (Transl. in
‘ Scientific Mcmoirs,’ vol. iv, p. 93. — A. II.)

158

THE PHENOMENON OE

duration. The primordial utricle seems to retract its
processes into itself, before it secretes tlie celliüose upon
its surface. Different, and especially instructive in
reference to the relation of the cilia to the internal body
of the cell, is the behaviour in a series of Algoid plants,
in which the ciliary motion is of lengthened duration,
and which on this account liave been hitherto included
among the Infusorial animalcules, namely, the Chlami-
domonada and the Volvocinem.* In Chlamidococcus
pluvialis, already mentioned above (p. 138), the active
cells, bearing cilia at the acute extremity, are bom naked,
like the swarming cells of other Algse ; but within a few
hours the periphery of the body exhibits a clelicate,
hyaline coat, which, by subsequent fluid secretion during
the about three-days-long duration of life and growth of
these “swarmers,” becomes removed farther and farther
froni the body of the cell, forming a separate membrane, as
it were, a loose coat around it. The ciliary motion persists
throughout this formation, only it gradually becomes
weaker and less active, since the cell-membrane becoming
gradually puslied up furthcr from the base of the two
long cilia, more and more hampers tlieir vibratile motion.
We liave here, therefore, indubitable evidence that the
cilia bclong to the proper body of the cell and the
primordial utricle bounding it, and not to the surrounding
cell-membrane. f Another Alga belonging to the same

group, which I liave called Glceococcus , produces, instead
of the more solid cell-membrane, a semifluid gelatinous
envelope, around its green body, which bears two very
long cilia at its acute extremity, and these become en-

* Yon Siebold (‘de finibus inter regnum animale et vegetabile,’ 1844',
p 12) was the first wbo distinctly claimed tbe Volvocinese for the vegetablc
kingdom. (See Williamson, ‘ Proc. Manchester Phil. Soc.,’ vol. ix ; ‘ Trans.
Mie. Soc. of London,’ 1853 ; also Busk, ‘Microscop, Trans.,’ 1853, p. 31.

fy Uj

f VideYon Plotow, ‘Act. Acad. Nat.Cur.,’ xx, p. 2, 1844, t. 25, f. 58—70 ;
in reference to which figures, however, I must observe, that I liave never
found the cilia retracted completely within the membrane. (Compare Cohn,

< Nova. Act.,’ xxii, and Abstract in this vol. ; also Schacht, ‘ Die Pflanzenzelle,’
p. 124.— A. H.)

REJUVENESCENCE IN NATURE.

159

tirely absorbed into the gelatinous envelope.* In Gonium,
Volvox, Pandorina , and a plant similarly formed ol eiglit
closely connected cells, which perhaps is Kützing’s
Botryocystis Morum , each cell likewise possesses two
cilia, which, issning froin the internal body of the cell,
project through the gelatinous envelope, and set the
whole fainily in motion by their vibrations.

The absence of a proper cell-membrane in the new-
born gonidia of the Algse is placed still further beyond
doubt. when their origin and birth is closely observed.
We will examine both somewhat more closely in JJlothrix
and (Edogonium. In JJlothrix, as above inentioned
(p. 149), the cells of the filament undergo raany divisions,
but always in the same direction, at right angles to the
longitudinal axis of the filament (horizontal division).
As soon as the division is completed, the contents may
be separated from the newly-formed wall by acids or
tincture of iodine, which proves tliat such a Separation is

* The genas Glceococcus exhibits the following characters : ovate, green
cells, with a colourless point, from which a reversed funnel-shaped, lighter
space extends inwards, together with a lavgish vesicle at the posterior
extremity. Multiplication by simple or double, in the last case decussating
halving, after which the cells remain loosely connected together by secretion
of soft gelatinous confluent coats, forming globular, and, finally, amorphous
families. The cells of all the generations succeeding each otlier during the
formation of these families (excepting- the transitory cells in the case of
double halving), are provided with two very long persistent cilia, which only
disappear when division commences. The cells exhibit a feeble motion inside
the enveloping and connecting jelly, the anterior end jerking in and out, or
suddenlv retracting a litlle. The last generation of the family leave the
gelatinous mass and swarm out, t,o settle down quickly in some otlier place.
It is probable tliat the formation of a new family is preceded by a longish
stage of rest, — perhaps there are several resting generations, — but we liave
no observation on this point. In Gl. mucosus the full -grown cells are Bidh 1°
j'Bth of a millimeter long, the “ phytodoms,” or family Stocks forming at the
bottom of liltle ponds, attain the size of an applc, and are of comprcsscd
globular, often lobed shape, tili tbey at length break up, and coine to the
surface of the water in irregulär fragments. The gelatinous mass has a
peculiar greenish spotted aspect, which depends upon subordinate groups of
generations being more closely packed together. Another form, perhaps
specifically distinct {Gl. mivor), appears in the springs at Freiburg, in the
spring, in the form of light yellowish-grcen, often pear-shaped “stocks,” at
most as large as a hazel-nut, attached to the sides of the gutters of the
springs, fmally becoming detached, swimming, and sliapcless. The cells are
somewhat smaller, ihoth to -läth of a millim. long.

160

TIIE PHENOMENON OF

possible, when a cell-membrane is very young and delicate.
With the commencement of fructification a new law of
division displays itself, namely,- a successive division of
the contents in the three directions of space, beginning
with two perpendicular divisions Crossing at right angles,
which are followed by the horizontal division, and sorae-
tiraesby another perpendicular division. These divisions
succeed one another so rapidly, that it is seldora possible
to see the first divisions without the last. Even this
circumstance renders it improbable that a formation of
cell-membrane takes place at once after every division,
enclosing the Segments ; and the phenomena occurring at
the birth of the germ-cells, which I shall sabsequciitly
describe, show completely the inadmissibility of such a
supposition. By progressive division, first two, then fonr,
then eight, and finally sixteen cells originate, in the way
described, in the individual link-cell. If each division
were immediately followed by a secretion of cell-mem-
brane, the originally simple chamber of the mother-cell
must become divided, successively, into two, four, eight,
and sixteen chambers, the soft plates of cell-membrane of
the newly-formed walls, since they would immediately
touch, must grow together, and the last parts (the germ-
cells) produced by the process of division would thus be
placed in a framework formed of a four-fold enclosure,
and solidified by the cohcsion of the vesicles packed one
inside another. Not the slightest trace of such an
apparatus of chambers can be seen at the birth of the
germ-cells. If, then, the separate divisions of the contents
are, nevertheless, followed by formation of cell-membrane,
the entire series of special parent-cells must, in the few
hours in which division and birth takes place, not only
be formed, but also immediately re-absorbed, an assump-
tion which here, as in other cases of transitory cell-
formation,* would appear altogether arbitrary, and

* The abscnce of formation of cell-membrane from many generations of
cells may be asccrtained with especial clearness in many 1 almellaccse, in
which, instead of a tliin, firm, cell-membrane, a thick, soft, gclatinous

RE.TUVENESCENCE IN NATURE.

lßl

unsupported by any observations. The birth of tlie
germ-cells of Ulothrix zonatci takes place in the following
way: — The mother-cell opens laterally by the tearing of
the cell-membrane ; the innerraost delicate layer of the
membrane of the mother-cell does not share in this reut,
but, swelling and expanding by absorbing water, and
loosened by this expansion from the outer membranes of
the mother-cell, it protrudes in the form of a sac. Only
rarely does this sac tear during its protrusion, and let ont
the germ-cells singly : in most cases it by degrees
emerges entire, and, as a globular vesicle. still holds
the germ-cells, already actively moving, imprisoned for
some time in its interior. Finally the sac bursts, and
the germ-cells separate rapidly in all directions. Even
after the emptying it may be still detected as a delicate
water-clear vesicle, without the slightest trace of
secondary mother-cell membranes in the interior. Soine-
times miscarriages occur, demonstrating the absence of
the latter still more absolutely. It happens, namely,
sometimes, that the germ-cells do not become detached
from the mother-cell vesicle, but remain coherent with it.
Such vesicles are born like the others; the included germ-
cells become separated from one another by the expansion
of the vesicle, without being able to leave its walls. In
these cases, again, no trace of interposed membranes can
be seen. I have observed a very similar process, without,
however, a tearing of the vesicle, in which indeed the
active germ-cells combine into a regularly-arranged
colony, in Pediastrum *

ln GEdoganium-\ only a single genn-cell is formed in

envelope is formed, offen alternating with more delicate membranous
lamellm, in which, therefore, the omission of the formation of these envelopes
is very striking. See, as an example, the ligure of Glccoci/.ilis vesiculosa in
Nägeli’s ‘ Einzelliger Algen,’ t. iv, f. The multiplication takes place tlirougli
simple or double halving, i. e. vegetative development and formation coni-
menees sometimes directly after the first division into two, sometimes after
the second ; the two transitory cells first formed producing no membrane.
The first case is represented in fig. n, the last in figs. o and f of the plate
cited.

* Vide plates iii and iv, and the detailed descriptiou in the Appendix.

f (See Thuret, ‘ Aun. des Sc. nat.,’ 3 scr., xiv, 17, pl. xix. — A. II.)

11

162

THE PHENOMENON OF

each cell of the filament. The birtli of these is effected
by an extremely regulär bursting of the parent-cell in the
direction of a transverse annular fohl, occurring near the
anterior end of the cell, so that the cell opens as it were
by a lid, the detached upper portion often remaining
fixed at one side, and openingonly laterally, the result of
which is of conrse a knee-like bending, when the opening
cell lies in the middle of the filament. The cell-contents
previously lying closely applied upon the cell-wall, and
merely betraying the impending birtli by their darker
colour, are then very gradually extruded through the
opening of the box-like cell, exhibiting, even duririg
the movement, at the posterior end lifted up from the
bottom of the cell, a brighter spot, which after the birtli
becomcs more distinctly developed as the nipple-shaped,
hyaline apex, bearing the wreatli of cilia. Düring the
birtli the germ-cell is here also preceded by an extremely
delicate vesicle, which gradually expands into a large sac,
the posterior end of which, however, never leaves the
mother-cell. This sac is often not torn through for
several minutes, but then it sets free the swarm-cell,
already revolving while inside, which darts away from it
like an arrow. The vesicle is here neither more nor less
tlian the innermost layer of the mother-cell, still soft,
taking no share in the dehiscence of the mother-cell, and
expanding by the absorption of water. It is coloured
distinctly blue by the application of tincture of iodine,
even without previous treatment with sulphuric acid.
That the germ-cell set free from its prison in the
manner described, does not yet possess a cell-membrane,
but represents merely the mass of contents of the mother-
cell, is testified, as in Vaucheria, byits want of cohesion.
I once saw, in (Edoyonium apophysatum a small torn-off
piece of the cell-contents left behind and assume the
skape of a separate globule, which did not arrive at
birtli and movement, but remamed in the cell. Probably
the original cause of the tearing in this case was a slight
adhesion of the cell-contents to the cell-walls, at a small

REJUYENESCENCE IN NATURE.

163

point in the hinder part of tbe cell. In Vaucheria clavata
I have often seen a Separation of the germ-cell into two
about equal portions, through a constriction* occurring
during the birth between the anterior, already born, and
the posterior portion still jammed in the elastically con-
tracting mother-cell (the club). I observed a similar case
in Stigeoclonium subspinosum. A germ-cell half born,
i. e., protruded through the lateral opening of the mother-
cell, became constricted by the contraction of the small
orifice of the elastic mother-cell, in such a way that the
posterior portion could no longer penetrate. The part
which had emerged, bearing the cilia, acquired a
tremulous motion, which became the stronger the more
the constriction cut it off from the posterior imprisoned
portion, tili at length it hung only by a fine thread.
Finally, the born portion broke loose and hurried away,
while the unborn piece remained behind in the mother-
cell. The entire process lasted some minutes.f

That the formation of the cell-membrane cloes not take
place until after the cell is separately constituted, is fur-
ther shown by all those cases in which the formation of
new cells takes place freely and without contact with the
membrane of the mother-cell. In the formation of the
restin g seed-cells of CEdogonium we see the thickish cell-
contents, composed of greenish coloured mucilage, mixed

* See the vivid description which Unger gives of this process (1. c.,
pp. 23-27). But where the author of this interesting treatise asserts that
the escape of the germ-cell of Vaucheria is passive, and not a rcally inde-
pendent act, I cannot agree with him. The swelling up of the club before
it tears, together with the hemispherical vaulting of the lower cross-wall
pressed downward in the filament, show clearly that the contents of the
club undergoing conversion into the germ-cell, acquire a development which
the firm membrane of the parent-cell cannot follow, so that this is brought
into a condition of violent Stretching, which results at length in a rupture,
and, in consequence of the contraction of the walls, the gradual squeezing
out of the germ-cell.

f (I have observed in a species of Chlamidomonas, while l'our active
gonidia were being set free by the solution of the cellular membrane con-
necting them as produced from a resting vegetative cell, one of tliem dividcd
into two, so that five were produced. 1 saw the entire process, which
occupied about an hour. — A. H.)

1G4

THE PHENOMENON OF

with Chlorophyll and starch vesicles, which, in the
earlier vegetative period of the cell, form a lining of
the wall, retreat from this membrane, and present
themselves as a new, everywhere free cell destined for
reproduction. The cell-body thus detached from the
walls, appearing in a new form, with a new vital direc-
tion, presents itself with regulär form and boundaries,
before a trace of the cell-membrane subsequently clothing
it is visible. It mostly assumes a perfectly globular
form, even when the mother-cell is longish ■* in this first
period of formation its surface appears somewhat uneven
from the projection of chlorophyll-vesicles ; the whole
internal cavity is filled up, and of deep green colour.
Very slowly and gradually tliere appears, first a simple,
afterward a double, and sometimes even a triple-layered
membrane upon the surface, while the Chlorophyll and
starch formations in the contents progressively vanish, and
give place to reddish oil-drops, wliich at length occupy
nearly the whole cavity, and give the seed-cell a brownish-
red, sometimes even a red-lead coloured appearance. The
seed-cells of the Zggnemacecß originale in the same way
as those of (Eclogonium , with the single distinction that
in the former the contents of two chambers become united
to form one seed-cell. f The formation of the cell-mem-

brane, succeeding the shaping out and limitation of the
cell, as a secondary phenomenon, may be well observed
also in Sjj/ueroplea.\ The links of this Conferva are of
unusual length, 10 — 20 times as long as broad. The
distribution of the contents is extremely elegant, and
allows, in some measure, of a comparison with that in
Spiroggra, with this diflerenee, however, that the Chloro-
phyll forms, not spiral, but annular bands, 20 or 30

* Tlius especially in (Edogonium Landsboroughii, Hassall.

f Viele INägeli, ‘Ueber freie Zcll-bildung.’ ‘Zeitschrift,’ 1847, p. 27.
(Transl. in Kay Society’s publicatious, 1849, p. 98.)

.f My observations ou this remarkable genus of Algse were raade in the
autumn of 1847, on Sphccroplea Braunix , Kz., (‘ Sp. Alg.,’ 462.) (Vide also
Fresenius, ‘ Sphcer. annulinu ,’ * Kot. Zeitung., 1851, vol.j ix, 241.
-A. H.)

REJUVENESCENCE IN NATURE.

165

of which girdle the internal cavity as green zones, in each
cell. In the median line of these zones are fonnd, as in
the spiral bands of Spirogyra , starch-vesicles, from five
to seven in each ring ; the surface of the rings, moreover,
appears spotted with very fine grannles, and the margins
irregnlarly denticnlated. The outer surface of the zones
lies flat upon the cell-wall, the inner surface projects with
a strong “ keel” into the cavity. The whole series of
zones are connected together by a delicate, colourless,
mucilaginous layer or primordial membrane, which lines
the whole of the internal surface of the cell-membrane,
and which is traversed by extremely delicate lines and
branched and anastomosing green longitudinal streaks
issuing from the teeth of the zones. But the strängest
peculiarity of the conformation of the cell -contents of
Sp/ueroplea lies in the chambering which occurs in them.
Each zone supports a delicate, colourless diaphragm,
arising from the annular keel or ridge, and stretchecl
across the cavity of the cell. These septa, which convert
the cavity of the cell into a many-chambered tube, have
no association at all with the external cell-membrane,
they are merely connected with the mucilaginous layer,
and forraed of the same substance as this. I have had
no opportunity of tracing the origin of these chambers,
as I have never been able to find Spharoplea in a suffi-
ciently young state ; but it can scarcely be doubted that
their presence and arrangement is to be explained by the
production of a row of water-bubbles in the originally
homogeneous contents (protoplasm) of the cell, which
idea is borne out by the not un frequent occurrence of
larger and smaller intermediate vesicles lying in the zones
themselves. The whole of this artfully arranged struc-
ture of cell-contents collapses as soon as the fructification
commences. First the zones become somewhat detached
from the cell-membrane, so that the internal tube appears
constricted by bands and articulated ; thcn the primordial
utricle, with the septa, vanishes altogether, the green zones

166

THE PHENOMENON OE

become broken up irregularly; we see them fall in, tear
up, and separate into little amorphous inasses. From this
solution the contents soon gatlierup into anew structure;
the irregulär green pieces become roundecl, and take the
shape of regulär, accurately defined globules, of which
two or tliree times as many are produced in each parent-
cell, as there were previously Chlorophyll zones present in
it. In the first period after their origin, these balls,
developing into seed-cells, exhibit a weak vibratory or
revolving motion, but tliey soon come to rest, and become
enclosed in a smooth, colourless cell-membrane, which,
however, is shortly afterwards peeled off again, and
replaced by a second, rougli and papillose cell- membrane
of considerable thickness.* The originally green colour
of the contents is gradually changed into a brownish,
brownish-violet or, in otlier species, bright red-lead colour.

Nägeli liasobserved in Bryopsis Balbisiana and otlier
Algae,f an abnormal formation of free cells out of the
broken-up cell-contents of old cells, notunlike the normal
formation of the seed-cells of Sphccroplea ; these observa-
tions also confinn the secondary formation of the cell-
membrane on the surface of portions of contents already
individualised, i. e. shapcd out into cells. With the Uist-
named phenomena may be associated the processes of
reorganisation, also observed by Nägeli, in injured and
partially decaying cells, | which show tliat the surface of
contents retracted from the cell-membrane by partial
disturbance, clothes itself anew with membrane by con-
tinuous secretion of cellulose, and indeed that the healthy
portion of the cell-contents has the power of cutting itself

* Kützing ascribes to the spores of a Splueroplea, an outer coat formcd
of a filiform structure wound spirally round the inner membrane, which
doubtless depends ou a misconception.

f Yide Nägeli, £ Ucber freie Zellbildung,’ 1. c., 24-26, t. iii, f. 1-3. (Transl.
in Ray Society’s publications, 1849, pp. 96-98, t. ii, f. 1-3.)

X Yide Nägeli, ‘ Wandständ. Zellbildung,’ &c. £ Zeitschr.,’ 1844,

p. 91-95, t. i, fig. 8, 11, 12. (Transl. in Ray Society’s publications, 1845,
pp. 26S-71, pl.'vii, figs. 8, 11, 12.)

REJUVENESCENCE IN NATURE.

1G7

off frotn the decay commencing in another part, by a
sharp line of demarcation, and of coating this boundary
with cell-membrane.

The Constitution and defined material isolation of the
cell before the formation of the cell-membrane, has been
observed in the free formation of the germ-cells of the
Phanerogamia, as well as in the germ- and seed-cells of
many Algae. According to Wilhelm Hofmeister’s re-
searches on the Origin of the embryo of Phanerogamia,*
researches widely extended and carried out with admirable
acuteness, — after the formation of a few nuclei the proto-
plasm accumulated in the end of the mother-cell of the
germ-cells (the embryo-sac) next the micropyle, divides
into two or three longish, rounded balls, each of which
encloses one of the nuclei. These balls display no trace
of a cell-membrane in their earliest condition, and when
they lie long in water, fall away into an amorphous semi-
fluid mass ; but they very soon become coated with a
cellular membrane, and then are no longer liable to
destruction, even from a long-continued action of water.
These cells formed free in the contents of the embryo-sac,
are the first rudimen ts of new plants, the germinal
vesicles, as they are termed, only one of which is usually
developed, through fertilisation taking place subsequently
to their formation.

That which does not admit of doubt, in the cases just
considered, where it is possible to observe the pro-
cesses on the free surface of newly formed cells, namely,
the secondary production of the cell-membrane around
the already existing and defined body of contents of the
cell, must certainly hold good also of those cases where
the division of a mother-cell into two daughter-cells is
apparently eftected through the formation of a mem-
branous septum. If it be once certain that the cell-
membrane is formed by secretion on the surface of the

* Vide Hofmeister, ‘Der Ensteliung des Embryos der Phauerogamen,’
(1849), p. 4 et seq.

1C8

THE PHENOMENON OE

cell, in tbis case also the forinatiou of the separating
membrane must be secondary, that is to say, the division
and opposite limitation of the contents of the two new
cells must take place before the septum can be forrned
between them by a secretion derived froin the two sides
and uniting at the surface of contact. Whether in this
kind of cell-formation, which is most simply distinguished
by the term cell-formation by clivision* the Separation of
the two cells takes place simultaneously over the whole
surface of contact, as Nägeli seeks to demonstrate, or
advances gradually, as it were by an annular constriction,
from the periphery to the centre, as Mohl represents in
some examples, and Unger assumes as the universal law
of vegetative cell-formation, is one of the most difficult
Problems in the study of cells. In a subsequent passage
1 shall endeavour to establish the existence of both con-
ditions. 1 f, in the latter case, namely the division of
the contents by a gradually advancing incision and
shutting off, the secretion of cellulose kept pace witli the
division, it would naturally result that the division would
seem to be effected by an annular process of the cell-
membrane growing in ward from the wall.

If we have recognised that the secondary formation of
the cell- membrane is the general rule, there can only
exist one more difference of opinion, namely, as to when
the secretion of the cellulose or allied substance on the
surface of the contained mass commences. ln mostcases
the commencement of this secretion would certainly coin-
cide witli the conclusion of the external limitation of the
cell-mass, as the moment in which the creation of the
cell, as an individualised sphere of formation, appears
completed, and the outward development of the cell
begins ; and the very young cell may therefore frequently
possess a delicate cell-membrane in such cases, where it

* Unger, ‘Ueb. raerismatisclie Zellbildung bei der Entwicklung des
Pollens/0 denominates tliis process merimatic cell-formation; (Nägeli,
« Zeitscbr.,’ 1844, p. 73,) calls it parietal cell-formation around Ihe whole
contents. (Ray Society Trans., 1845, p. 252.)

I

REJUVENESCENCE IN NATURE. 169

appears to be still devoicl of a coat. Only transitory cell-
formations, as I have endeavoured to show in certain
examples above, remain without a coat of cell-membrane,
and in the active gonidia of the Algee (with the exception
of the permanently moving cells of the Volvocinese), the
commencement of the formation of the cell-membrane, in
all probability, does not comnience until after the stage
of ciliary motion, the endurance of which is, however,
mostly very short, never extending beyond a few hours.

We have already ascribed, in the foregoing, the
accurate limitation of the cells not yet clothed with a
cell-membrane, to a coat belonging to the very bocly of
the cell, not to be confounded with the cellulose envelopes;
and we have sought especially to characterise as an
example of this, the ciliated coat of the gonidium of
Vaucheria, which may fully claim the title proposed by
Mohl — “ primordial utricle .” Whether, however, the

occurrence of such a coat, distinguishable from the
remaining mucilaginous contents or protoplasm of the
cell, as we see it in Vaucheria, is an universal pheno-
menon, or whether the primordial utricle described by
Mohl* is not rather a mere coat of protoplasm, a layer of
mucilage lining the inside of the cell-wall,f produced
through the protoplasm, originally wholly filling the cell,
becoming excavated by a cavity filled with watery fluid,
is a question which requires for its settlement more exact
and extensive researches than we at present possess.
isolated, easily observed cases do indeed indicate that
the mucilaginous layer of full-grown cells is not a simple
protoplasmic investment, but is composed of two or three
differently organised layers, the outermost of which, re-
presenting the proper coat of the cell-contents, is very
probably formed in the earliest period, as the original

* Vide H. von Mohl, ‘ Bemerk üb. den Bau des veg. Zelle.,’ Bot. Zeit.,
1844, p. 275. (‘Trans. Taylor’s Scient. Memoirs,’ vol. iv, pp. 91-92) ; and
‘ Ueb. die Saftbew im Innern der Zellen,’ ‘Bot. Zeit.,’ 1846, p. 74. (‘Transl.
Annals of Nat. Hist.,’ vol. xviii, p. ], 1845.)

t This is Nägeli’s view, (‘ Zeitsehr.,’ 1844, p. 91, — 1847, p. 38).
Transl. in Ilay Soeiety’s publieatious, 1845, p. 268, — 1849, p. HO.

170

THE PHENOMENON OE

boundary structure of the cell-mass (the portion of Con-
tents becoming individualised into a cell), and in this
case, just like the coat of the gonidium of Vaucheria,
claim may be made to the title of 'primordial utricle.
Thus, in the Characeae we find a mncilaginous layer,
thicker or thinner in proportion to the age of the cell, in
circulating motion ; but outside the circulating mucilage
exists a motionless soft coat, to which are attached the
regularly arranged Chlorophyll vesicles. In the earliest
stage of formation of the cell, before the commencement
of the circulating motion, the mucilaginous contents,
surrounding a nucleus, fill up the whole cavity of the
cell. The flowing movement, vvliich carries along with it
the nucleus still visible for some time, first commences
after a hollow space filled with water has beeil formed in
the cell ; but the separate formation of the primordial
membrane taking 110 share in this motion, must liave
beeil coinpleted before the commencement of the circu-
lation. In (Edogonium , in the contraction of the contents
connected with the deatli of the cell, we frequently see
the mucilaginous layer divide into a double utricle, an
outer, lighter coloured, and an inner, darker coloured,
and never contractcd. The compound nature of the
mucilaginous layer of (Edogonium may be detected even
in the living cell, by the different arrangement of the
Chlorophyll in the two layers. In the outer layer the
Chlorophyll forms delicate longitudinal streaks, anasto-
mosing liere and there, and thus forming a network with
narrow meslies ; the Chlorophyll vesicles, which are ulti-
mately arranged in rows, are formed in these originally
amorphous streaks. Inside this light-green, long-streaked
net, we see, especially clearly in (E. fonticola and CE.
capillare, a coarser, darker green net, forming a few
irregulär meslies, extending more in a cross direction, in
which net are imbedded large starcli vesicles (in the
former species one or two, in the latter a greater number).
In this inner layer is found also the parietal nucleus,
remaining visible for a very long time. Finally, in

REJUVENESCENCE IN NATURE.

171

Jlydrodictyon, I have most clearly observed a coniposition
of the mucilaginous layer of three distinct laniellae. When
the cells of the full-grown Water-net are treated with
dilute hydrochloric acid, the entire conterits are ordinarily
contracted from the cell-membrane as a closed utricle or
tube, smooth on the surface, and no laminar Separation
can be detected in it. Sometimes, however, and as it
appeared to me, in diseased cells, previously near their
dissolution, there occurred, as in (Edoyonium , a Separation
into an outer paler, and an inner, clark-green utricle, the
former exhibiting a smooth, the latter a rough surface,
and remaining connected here and there with the outer
utricle by thick mucilaginous threads or trabeculce , which
originated through the inner, inore strongly contracting
utricle, drawing out the mucilaginous substance of the
outer in the form of filaments, at the.se points, where it
does not become completely detached from it. This
plienomenon would not speak in favour of a membranous
structure and consistence of the outer utricle ; but further
investigation shows that this outer utricle is not simple,
but formed of two distinctly different layers, an extremely
delicate pellicle, accurately defined inside and out, and a
less sharply defined, somewhat thicker layer of mucilage,
— which two layers separate from one another at various
places, so that they may be very clearly distinguished.
The entire contents of the cell of Hydrodictyon exlnbit,
proceeding from without inwards, the following sections:
1. The primordial membrane. It is of scarcely mea-
surable thickness, colourless, opakish, and very finely
and uniformly punctated, which depends on its being
composed of closely conjoined, extremely minute globules,
which, according to my estimate, can be at most between
To7x.fl1 and — th of a rnillim. in diameter. This extremely
delicate structure has a totally different character from
the inmost layers of the cell-membrane, for it is dimin-
ished in diameter, and retracted from the cell-membrane
by the action of acids, while the inmost layers of the
ccllulosc rernain connected with entire cell-membrane,

172

TUE PHENOMENON OE

and indeed swell up more strongly than the outer layers,
thus often falling into wave-like folds. The layers of the
cell-raembrane do not exhibit the slightest trace of punc-
tation, or of a composition from globules ; they are
always horaogeneons and hyaline.

2. The outer mucilaginous layer. This is thicker than
the primordial membrane, but far thinner than the inner
mucilaginous layer. When separated from the primordial
membrane, its outer surface appears rough and wavy, as
also its inner surface, which is connected here and there
with the inner mucilaginous layer by stretched mucila-
ginous threads, and hence often appears torn on the
inside. It is also opakish, of a yellowish colour, and
exhibits largish, irregulär, and indistinctly defined tnuci-
lage-granules.

3. The inner mucilaginous layer. This is the thickest
of the thrce layers, rough on the outside, wavy, and
exhibiting large, strong projections on the inside, dc-
pending on the starch-vesicles occurring in it. Only this
layer is green, and, indeed, in vigorous and healthy cclls,
of a continuous green colour, strewn over besides with
innumerable, mostly rather largish, dark-green granules,
about f^gth of a millimet. long, which sometimes form
interrupted, curved, and much intertwined rows, but more
frequently appear uniformly scattered. These granules
are not yet distinguishable in young cells. This layer
also contains the starch vesicles, which appear as bright
globules, of at most Tföth of a millim. thickness. Their
number increases with the age of the cell; while the
young cell, in the first day of the formation of the net,
possesses only a single starch vesicle, on the second at
most 2, on the tliird 3 — b, on the fourth 5 — 10, vesicles,
the full-grown cell, about three weeks old, displays
several thousands of them, which give the Water-net a
beautifully punctated appearance,* and were wrongly

* Vaucher, ‘Histoire des Conferves d’Eau douce,’ 1803, described the
starch vesicles as yrains bnlluns, and considered them the male Organs of
Hydrodidyon.

REJUVENESCENCK IN NATURE.

173

imagined by Aresclioug* to be the rudiments of the active
gerai-cells. When the cells are less perfectly developed,
the internal mncilaginous layer exhibits a reticulated ap-
pearance, formin g very irregulär green meshes on a yellow
ground. Whether, in this case, these are real reticu-
lated perforations, or the Chlorophyll merely is contracted
within a continuous mucilaginous layer, I shall leave
undecided. I mention this reticulated structure in Order
to observe, that although it vanishes subsequently on the
more vigorous development of the cells, it is a normal
occurrence in the young cells, and commences even on
the first day of existence, by the green contents, originally
uniformly filling up the cell, contracting into a broad green
zone, which divides more and more in the succeeding
days, and so gradually passes into the formation of a
many-meshed net, a phenomenon which at the same time
indicates that the Separation of the contents into the
various layers occurs in the very earliest youth of the cell .

4. The fluid, which fills up the interior of the three-
fold sac. It is of watery consistence, and no further
organic parts can be distinguished in it.

Thus, then, it is shown that the cell-contents form a
far more perfectly organised body than is ordinarily
imagined ; that they exhibit a multiplicity of differences
of Organisation, which are no less important than the
differences of the cell-membrane, to which vegetable
anatomists have hitherto almost exclusively paid attention,
and which after all may themselves be merely results of
special peculiarities of the contents. As the modifications
of the structure of tha cell-wall have been used, not only
lor the distinction of the different kinds of tissue, but
even lor the characterisation of the great divisions of the
Vegetable kingdom, so must the differences of the Organi-
sation of the cell-contents, which have hitherto found

* Areschoug, ‘De llydrodictyo Utriculato,’ ‘Dissert. Bot.,’ Limdae,
1839, Linnsca, 1842, and JEassall’s ‘ Frcsh-watcr Algoe,’ 225.

174

THE PHENOMENON OF

sorae application only in systematic Algology, as generic
characters,* be taken more and more into account.

Among the essential parts of the Organisation of the
cell, is also the cell-nucleus or cytoblast, as it were a cell in
the cell, mostly containing in its interior again a nucleolus
(nuclear corpuscle, kernkörper chen). Nägeli’s extensive
researchesf lmve demonstrated its occnrrence in all
divisions of the Vegetable kingdom ; only in particular
families of the Algae, as, for example, in the Palmellacese, :{:
Chroococcaceae, Oscillatorineae, and Nostochineas, as also
in the large-celled Cladophorce , and the mricellular
Algae, with unlimited grovvth of the cell ( Vciucheria ,
Codium , Caulerpa ), no trace of a nucleus has yet been
discovered. Schleiden § was the first to direct attention
to the importance of the nucleus and its relation to the
original formation of the cell. It undoubtedly originates
before the cell is outwardly defined ; it is thus, in the
truest sense, a central organ, around vvhich the vital
circle of the new cell is drawn.|| Originally it is always
situated more or less in the centre of the protoplasm
by the subsequcnt development of a cavity in the in-
terior of the cell, it mostly becomes parietal, i. e.,
imbedded in the layer of mucilage fonning the internal

* See cspecially the family of the Zygnemaceaj, as also the Desmidiacese,
in whieli latter Niigcli has founded the more accurate diagnosis of the
genera in part upon the condition of Organisation of the cell-contents,
(‘Einzell. Algen.,’ p. 100, t. vi-viii).

f ‘Zeitschrift, für Wiss. Botanik,’ 184:4, pp. 34-G8. Transl. in Ray
Society’s publications, 1845, pp. 215-24G.

+ In the genus Chlamidococcus, at least allied to the Palmellacesc, (see
above, pp. 138 and 158), I liave found in the cfcntrc of the cell a vesicle Glied
with fluid, doubtless corresponding to the nucleus, surrounded and con-
sequently liidden by the oily (?) red colouring matter of tliis plant. In
most of the true Palmellacero there is a chlorophyll-vesicle in the centre of

the cell.

§ ‘Beiträge zur Phytogenesis,’ ‘Muller’s Archiv,’ 1838. Transl. in
Scieutiflc Memoirs, vol. i, p. 281. _ , . , , ,

II Yide, in reference to tliis especially, Nageli, ‘Ueber Entwicklung des
Pollens,’ (1842), and Hofmeister, ‘Enstehung des Embryo der Phanero-

gamen,’ (1849). „ . TT. , , ...

H von Mold, ‘Bot. Zeit.,’ 1846, p. 76. (‘ Ann. Nat. Hist., xvm, 3.

— A H.)

RE JUVEN ESCEN C E IN NATURE.

175

investment of the cell; tlms in the filaments of the
genera (Edogonium and TJlothrix. It then often appears
surrounded by radiating streaks of mucilage, e. g., in
the embryo-sacof the Phanerogamia,* * * § frequently becomes
the starting point and centre of the circulation occurring
in such threads of mucilage, as is seen most beantifully
in the hairs of the stamens of Tradescantia ; f or, finally,
it is itself carried along by the current, as is the case in
the Characeae (where, however, it soon vanishes) and
Vallisneria.% More rarely the nucleus retains its central
position in the hollow cell also, when it appears as if
suspended in the centre of the cell by an apparatus of
radiating mucilaginous threads, as may be seen most
beautifully in Spiroggra .§ In Zygnema it is held in the
centre of the cell by a strip of mucilage, which connects
two large starch-vesicles, these being again connected
with the wall of the cell by radiating mucilaginous
filaments, rieh in Chlorophyll. The Fucoicleae|| also
exhibit a central nucleus, occupying the middle of a
delicate circulation-network. In Closteriuru% the nucleus,
with its colourless mucilaginous envelope, is maintained
in the centre of the spindle-shaped cell by the green
lamellae of contents, arranged radiantly around the long
axis of cell, which lamellae are interruptecl by it in the
middle of the cell. In many cases it seemed to me to be
surrounded, as by a band, by a cavity containing water.
In the cells of the delicate links of the antheridium of
the Characeae, lastly, the nuclei are so large that they
occupy the greater part of the cell, sometimes occupying
the centre, sometimes «pushed a little to one side.

* Viele Hofmeister, 1. c., t. ii, f. 18-26.

t Mcyen, ‘ Pflanzen Physiologie,’ ii, t. viii, f. 6-10.

% Ibid., f. 2, and Schleiden, ‘Grundzüge,’ p. 293, f. 91, ‘Principles of
Sc. Botany,’ p. 93, f. 95.

§ Schleiden, 4 Grundz.,’ ii, t. i, f. 7 ; ‘ Principles,’ t. i, f. 7.

|| Nägeli, ‘Zeitschrift,,’ 1844, p. 43, t. ii, f. 1-3. (ßphacelaria scoparia
and Zonaria Pavonia.) Transl. in Ray Soc. public., 1845, p. 222, pl. vii,
fig. 1-3.

H Vide Pocke, ‘ Phys. Studien.,’ t. iii, f. 11 and 26; Nägeli, ‘Einz.
Algen.,’ t. vi, c, d, e.

176

THE PHENOMENON OF

I have prefaced witli tliese few indications of tlie
strncture of the cell, in order to give a preliminary
characterisation of the essential parts, the behaviour of
which will be of importance to us in the phenomena of
Rejuvenescence of the cell.

II. DESTRUCTION ( Enthüllung ) OF THE CELL.

“The question of the raultiplication of cells includes,”
says Schleiden,* “ the origin and the life of the entire
plant.” With better right may we say tliat the exaraina-
tion of the Rejuvenescence of the cell includes tliat of the
whole life of the plant ; for there are plants which run
through their entire vegetative vital development in one
single cell, consequently without multiplication, but not
without partial Rejuvenescence of the cell. The multi-
plication of cells itself is nothing elsc than a phenomenon
of Rejuvenescence of the cell. All Rejuvenescences in
cell- life, however, are connected with a more or less
deeply invading destruction of the already Consolidated
parts of the cell standing in Opposition to a progressive
development. These phenomena of undoing and Stripping
off the proper earlier structures of the cell, are what
we have liere to examine first of all, and this, first
in reference to the coats, then in reference to the con-
tents of the cell.

The cell-membrane, by its hardening and lamellar thick-
ening, sooner or later becomes an obstacle to the growth
and the vital development of the cell or its successors,
the daughter-cells forming within the mother-cell mem-
brane. Numerous cells attain the aim of their life with
the complete formation of the cell-wall, as, for example,
all über- and wood -cells, the spiral vessels, &c. In other
cells, on the contrary, we see the living process overcome
the straitening case, sometimes through mechanical

* ‘ Gruudziigc,’ i, 304 (2te Aufg.) ‘ Priuciples/ j>. 102.

RUJUVENESCENCE IN NATURE.

177

bursting, and soraetimes through cliemical softening and
solution. The cases of forcible tearing of the cell-mem-
brane are themselves of varied kinds ; we distinguish: — 1 ,
tearing of the cell-membrane, without its being wholly
peeled off; 2, complete peeling of the cell-membrane,
skinning of the cell ; and, 3, slipping-oul of the rejuvenised
cell-structure from the old inembrane.

1. One of the most beautiful examples of the tearing
of an outer cell-membrane, from its not keeping pace
witli the growtli of the inner cell, has been described
by Schimper* in the paraphyses of Diphyscium foliosum.
These paraphyses are composed of a simple row of cells,
which become very considerably elongated during the
completion of tlieir development. As soon as they have
attained about half their length, the outer cell-membrane
splits annularly in the middle of the cell, like a circum-
scissile capsule ; the two halves separate and remain
attached upon the links as bell-shaped or bowl-shaped
collars, while the cells continue their longitudinal growtli,
sometimes opening and retracting their walls in the same
inanner a second time. I have observed in certain
Confervae, especially Utothrix Braunii,\ and Zygogonium,
ericetorum, conditions comparable with the process in
Diphyscium. The delicate filament of the first-named
plant is composed of a row of cells, which divide by
double horizontal division, each into four cells. The
membrane of the mother-cell of tliis group of four cells
tears crossways, during tliis process of division, into two
equal halves, which remain as short, abrupt sheaths on
the upper and lower ends of each four-celled group.
Zygogonium ericetorum exhibits the same phenomenon in
manifold repetitions, and even in cells which have ceased
to divide, and are only undergoing elongation ; but the

* W. P. Schimper, ‘ Recherches sur les Mousses,’ (1848,) p. 52, pl. vi,
f. 42-46.

f Kützing, ‘ Spec. Alg.,’ p. 346. The above-mentioned species can
scarcely be included in the same genus with Ulothrix zonata, since it fonns
only two germ-cells in a mother-cell, which, moreover, possess not four, but
only two cilia, as in the aqual ic Hormidia.

12

178

THE PHENOMENON OF

persistent, double or triple, firmly connected sheatlis
are not so clearly distinguishable as in ülothrix Braunii.
The escape from the mother envelope is exhibited in a
different way in the Scytonemese (especially ftnely in
Arthrosiphon) and Rivulariese (especially in Schizosiphon
and Euactis ). Here it is not the individual cell, but a
whole series of cells, wliich breaks through the enveloping
membrane. In these genera a connnon coat of either
leathery or gelatinous consistence is formed around the
whole row of cells, through the cells separating only
by their side-walls (not at the joints of the link-cells.)
With the progress of longitudinal growth, this produc-
tion is rcpeatcd, so tliat numerous layers are formed, the
outer of which, however, are successively brokcn through
at the upper end, remaining as open funnel-shaped
sheatlis, one fitted inside another, no longer shutting np
the upper end of the filament. In Arthrosiphon these
funnels are short, pale-coloured, and transparent, whence
this elegant genus is especially fitted to exhibit the true
structure of the compound sheatlis in the said group of
Algac. In 8 cytonema the sheathing funnels are longer,
thinner, and very firmly connected, so that the entire
sheath assumes merely the appearance of one many-
layered sheath, clearly streaked with oblique lines,
however, in the longitudinal section. In Euactis, lastly,
the delicate and soft funnels separate into loose lamellse,
whence the lateral view which is obtained by the
mieroscope exhibits the appearance of a fibrous breaking-
up of the outer surface of the sheath. The phenomenon
of unilateral rupture of the coats is exhibited again in
another way by the remarkable genus Urococcus * of the
family of the Palmellacea3.

The large, globular, brownish-red or blood-red cells of
this genus, throw off colourless layers of cell-membrane,

* Yide Hassall, ‘British Fresh-water Algae,’ (1845,) t. lxxx, especially
figs. 4 and 6. A form belonging to this genus, apparently standiug between
U. Hookerianus and U. insignis , occurs on the elevated moors of the Black
Forest.

REJUVENESCENCE IN NATURE.

179

which, as in Glceoccipsa, appear to be separated by inter-
mediate layers of softer jelly, whence arises a distinctly
concentric structure of the envelope. But the enveloping
layers of Urococcus do not retain tlieir original form and
integrity ; not increasing themselves in size, thejr are
pnshed off on the upper side by constantly succeeding
inner coats, being at first merely attenuated at one side,
but subsequently, as it seemed to me, actually broken
through. Since this emergence from the old coats is
always repeated on the same side, a membranous-gela-
tinous pednncle is produced, formed of cups fitted one into
another, so as to give an annularly streaked, apparently
shortly artioulated aspect. The red cell, which occupies
the summit of this peduncle, sometimes divides, and
this of course produces a subsequent dichotomy of the
peduncle. If the periods of the formation of the separate
enveloping layers were known, the age of the little plant,
wliose history is preserved in the gelatinous peduncle,
might be determined by the n umber of rings. As a last
example to be included here, I may mention the forma-
tion of the so-called veil of Zonaria Pavonia * The fan-
shaped thallus of this Alga possesses two unlike surfaces,
one of which, the outer or back surface, in reference to
the early unrolling of the thallus, is clothed with a layer
of smallish cortical-cells, these becoming coated with a
thickish membranous layer, comparable to the cuticle of
higher plants, by more active development of membrane
on the side next the surface. From these cortical-cells are
developed the fructification-cells and paraphyses, in
alternating zone-like collections (sori). The former
originate from a division of the cortical-cells, parallel to
the surface of the thallus, into two unlike daughter-cells,
the lower of which retains the character of a cortical-cell,
while the upper emerging from the surface of the thallus,
becomes the mother-cell of the spore ;f the latter (the

* Vide Kützing, ‘Phyc. GeD.,’ t. xxii, 1, and Niigeli, ‘ Algcnsyst.,’ p. 180
t. v, f. 2, 3, 7. r

t Kiitzing and Nägeli regard this as the secd-cell itself, (“ Sperntalium,”

180

THE PHENOMENON OE

paraphyses) originale by similar elevation and division of
the cortical cells, which, however, is repeated several
times. The cuticle, at the sarae time, is incapable of
sharing in this development of the cortical cells ; it is
separated from the sorus as a connected pellicle, pushed
upward, torn up at one side and tlirown over, so that it
looks not unlike the indusium of.an Asplenium.

2. The complete skinning of the cell, the real peelin g
off of an outer cell-membrane, wliile the inner follows
the new development of the contents, is displayed in the
germination of the Mosses* and Ferns ;f it doubtless
occurs also in the germination of all the thick-coated
spores of Algae, when they awaken from the stage of rest.
It was secn by Vaucher in the Zygnemaceae,t and
according to my own researches (already mentioned
above, p. 135) it is double in Spirogyra for two mem-
branes arc stripped off in succession. The stränge
skinning of the newly-formed spores of Splueroplea has
also been mentioned (p. 166). And the peculiar manner
in which the spore of Equisetum frees itself from its
mother-cell membrane, Splitting into two right-wound
spiral bands,|| may be callecl a skinning. Bnt we find
skinning of the cells connected not unfrequently with the
vegetative development and multiplication of the cells by
division, among the Unicellular Algte. The Stripping off of
the mother-cell membrane connected with the multiplying
division of many Desmidiacese, was described and figured
by Fockc^l in Closterium Trcibecula. The cell-membrane

Kz., u germ-cell,” (/ceim-zelle,) Näg.); but Decaisne, (‘ Classif. des Algues,’
p. 26,) States distinctly timt the spores escape from it by rupture, wliile it
remains beliiud upon the thallus as an cmpty perispore.

* W. P. Schimper, ‘ Recherches sur les Mousses,’ t. i.

f Leszczyc-Suminski, ‘ Zur Entwicklungsges. der Earrenkräuter,’ (1848,)
t. i.

t Vaucher, ‘ Hist, des Conferves d’Eau douce,’ t. iv, f. 5 ; t. vi, f. 4.

§ (See Pringsheim, Transl. from the ‘ Flora,’ in ‘ Annals of Nat. Hist.,’
2d ser., vol. xi, p. 210. — A. H.)

|| Mohl, (‘ Flora,’ 1833, p. 45, and ‘ Verm. Schrift.,’ p. 72, t. ii, figs. 6, 7),
represents these bands as left-wound, an error which probably arose from
neglecting the use of the mirror in the first lithographing.

^[Focke, ‘Phys. Studien.,’ p. 75, t. iii, f. xvii. According to Ralfs,

REJUVEN ESC ENGE IN NATURE.

181

tears at both ends, and the two stick-shaped young ones
strip it oft', slipping out from the two opposite sides ot
the old coat, like a finger from a glove. I have observed
a similar skinning in Euastrum ( Cosmarium ) margariti-
ferum.* In Closterium ( Penium ) curtum, f on the other
hand, I saw the mother-cell membrane tear cross ways, in
the middle, during the division, so that its two halves
separated and were stripped off by the two new indi-
viduals on opposite sides. I have observed a very pecu-
liar mode of the phenomenon of skinning in a new genus
of Palmell aceae, which I have called Schizochlamys.\ The
globular cells of this little Alga produce a hyaline cell-
membrane, which becomes removed to some distance
from the green body of the cell by subsequent secretion
of fluidish jelly ; soon, however, (probably from endosmose,)
becoming unable to withstand the expansion of the jelly,
it splits in the direction of an equatorial circle, by a clean
line, into two similar halves, or, if the dehiscence takes
place by two circular lines cutting at right angles, into
four similar pieces. This Splitting and peeling of the
membrane, either coincides with a division of the internal
cell-mass, or it occurs without any such division. By
frequent repetition of this process the cell gradually
becomes surrounded by an accumulation of old fragments
of the membranous sliell, which are held together by the
extremely transparent jelly set free. The division of the
cell may be either a simple halving, in which case each
part is immediately clothed again with a hyaline cell-
membrane, or double, through the cells produced by the
first division separating immediately into two cells, without
previously acquiring a coat of cell-membrane, and therefore

Closterium. Trabecula belongs to the genus Docidiim; according to Nägcli,
to the genus P leurotainium. Pocke, moreover, eonfounds at least two
distmct spccies of this genus under liis Closterium Trabecula.

I' ocke, 1. c., t. ii, Hg 17, represented in division, but without notice of
the skinning.

t Ralfs, ‘ Brit. Desmidiese,’ t. xxxii, f. 9.

+ Kiitzing, ‘Sp. Alg.,’ p. 891. Pefkaps Hassall’s Sorospora virescens ,
(llass., t. lxxviii, f. 8, «,) may belong to my Scliizochlamys cjelutinosa.

182 THE PHENOMENON OE

without skinning.* I kave also seen a skinning of tlie
cell by irregulär tearing and exfoliation of the outer
lamellse of very much laminated cell-membranes, ex-
hibited very beautifully in Chroococcus decorticans ,f a
species very closely allied to Clt. rufescens (Näg. ‘Einz.
Alg.,’ t. i, a) and Ch. turgidus (Kütz. ‘ tab. pliyc./ 6).
I have also met with irregulär burstin g and peeling off
of the outer coats of multicellular families, or sometimes
also of isolated cells surrounded by manifold coats, in a
Glceocapsa , with dark purplish-brown coats, standing
near to Gl. Magma (Kütz. ‘tab. pliyc./ 22); also in
Glceocystis vesiculosa, Näg., and Gl. ampla ( Glceocapsa ,
Kz.). Nägeli also figures a skinning in Pleurococcus
miniatus (1. c., t. iv, e. ö).

3. The slipping-out, or better, the expulsion from their
old membranes of rejuvenised cells, intimately trans-
formed, and passing into a renovated development, is dis-
tinguished from the skinning of the cells just examined,
in that the cell-membrane is not stripped off the resting
body of the cell, but, vice versa , the coat, remaining in
its jdace, drives out the contents separatin g from it, after
the latter have burst.the envelope. This occurs parti-
cularly in the cases wliere the cell discharging its con-
tents is fixed, either by an independent attaclunent, or
belonging to tissue, by connection with its fellows. In
free cells no accurate limit can be drawn between
skinnning and slipping-out of the contents. Slipping-out
is the ordinary process by which the reproductive cells
of many Algae, Lichens, and Fungi, emerge from their
mother-cell chambers; if they are active, it is at the same

* Vide plate ii, and the cxplauation. •

f The cells of this new species are smaller than in its two allies, from TJB
to gj, millim. in diamctcr, and verdigris green ; the colourless membranous
layers tougher, more clearly distinguishable. When the divisions of the
cell succeed rapidly, the thin coat exhibits but four layers; when the
division is intermitted, numerous (8—10) layers of membrane are found,
offen appearing thickened on one sidc, and finally exfoliating irregularly.
Tincture of iodine colours the contents reddish or yellowish-brown, the
coats golden yellow. It occurs on the walls of the tufa cavcs near St. Aubiu
on the Neunburger Sca.

REJ UVENESCENCE IN NATURE.

183

time a “ swarming-out,” in which the peculiar motion
begins sometimes durin g the birth, or even before the
birth, inside the parent envelope. The onnce m the
mother-cell membrane, as in “ skinning,” may be either
an irregulär rupture or a regulär dehiscence. The con-
tents left in the old coat are either undivided, entering
upon their altered destination as a whole, or divided,
i. e. separating into several cells in the transition to a new
course of life; the cells eoming to light are sometimes naked
gonidia, sometimes spores already clothed with a new
cell-membrane. We have already had cause to examine,
in detail, many of the examples to be cited here, so that
it suffices merely to recall thein to recollection. A single
active germ-cell frees itself from its chamber by dehis-
cence of the latter at the apex in Vaucheria {viele supra,
p. 163); in Gongrosira Sclerococcus* by tearing at the
apex or the side, according as the mother-cell is an
apical-cell or a link-cell ; by bursting of the back-wall of
the cells of the circular thallus adherent by its lower
surface, in Coleocluete scutata {vide supra , p. 141) ; by a
lateral Splitting of the cells of a shrubbily-branched thallus
in Coleochcete pulvinata (p. 142), Chcetophora, Stigeoclo-
nium, and Draparnaldia (p. 138) ; by annular dehiscence
at the upper end of the cells in (Edogonium (pp. 141 and
162) ; by disarticulation of the laterally attached bristle-
cells and breaking-open of the septa separating them from
the link-cell of the ftlament in Bulbochceie (p. 141). A
single resting cell is set free from its coat (the perispore),
and this by dehiscence at the apex, in Chantransia
(p. 143), Chroolepus (?), and the Fucoideee in theextended
sense. f Two active germ -cells slip out from a mother-
cell, breaking through it laterally, in Ulothrix Braunii

* Obäerved in July, 1847. The almost globular gonidia posscss four
cilia, like the allied genera Chcetophora, Sligeoclonium , &c.

t Alga pyenospermem et anaiospermea, Kiitzing. In regard to the exist-
euce ol a perispore, vide the observations on Zonaria, p. 179. Decaisne and
Tlmret also figure perispores visible even aller the slipping out of the spores
in Fucm nodonus and serralus, (‘Ann. des Sc. nat.,’ 1845, t. i, c, f. 21, and
t. ii, f. 32).

184

TIIE PHENOMENON OF

(see p. 177); by breakin g through the back-wall of the
cell of a creeping filaraent in Aphanocluete repens.* I
have observed fonr active germ-cells expelled through a
breaking across of the mother-cell exactly in the middle
in Conferva bombycina ;f J, Agardh likewise saw four
active gonidia emerge from the cells of JEnteromorpha
clathraia 4, 8, or 16 break out laterally, in the way
described above (pp. 148, 161), from the parent-cell of
TJlothrix zonata. Chlamidococcus pluviaiis (pp. 138,
1 58) may be mentioned again here. Four (rarely two or
eight) active cells emerge from the thick-coated, resting
(seed-) cells by irregulär dehiscence of the cell-membrane,
during which Operation the innermost extremely delicate
layer of the mother-cell membrane becomes detached,
partially emerging as a vesicle, and tearing subsequently
to the outer tliick cell-membrane. The gonidium-like
cells gradually produce an extremely delicate membrane
over thcmsclves in the way above described, inside which
tliey finally divide again into 4 (rarely 2 or 8) parts,
or, when the formation of microgonidia takes place, into
32 parts, which begin to move about inside the roomy
coat even before tliey swarm out. In Pediastrum (p. 161)
4, 8, 16, 32, or 64 active gonidia, enclosed by the
vesicular inner layer of the mother-cell, break out by a
tear in the old cell. A larger number of active gonidia,

* Aphanocheele is a new genus of Algse, which perhaps will have to be
united with Herposteiron, (Kz., ‘ Sp. Alg.,’ p. 424,) from which it differs
through the absence of the vertieal torulose branches. The bristles, which
frequently spring from the back of the cells, are not sheathed, as in
Coleocliate, yet articulated in the upper part, but at the same time so
delicate that the upper portion is difficult to make out. The formation of
the pairs of germ-cells takes place by division parallel to the septa. The
germ-cells are nearly globular, possessing two cilia. A. repens occurs not
uufrequcntly near Tr ei bürg, particularly on i Edogonia , Vaucheriee , Mongeotia,
Sirogonium, Conferva, &c. I observed the swarming of the germ-cells in
August, 1847.

f Observed in October, 1847- It is remarkable that the formation of the
germ cells of this very common Conferva has been but seldom observed.

X ‘Ann. des Sc. nat.,’ 1846, p. 199, t. xii, f. 6. According to Thuret,
(« Arm des Sc. nat.,’ 1845, p. 274), the gonidia of JJlva and Entcromorpha
possess four cilia.

REJUVENESCENCE IN NATURE.

185

forined in like manner by repeated division of the cell -
contents, break through the mother-cell ot Cystococcus *
C/iaracium,i and Ectocarpus.% Very numerous swann-
ing-cells, not formed by successive division of the green
contents, but by simultaneous division of the mucila-
genons layer alone, issue through irregulär lateral
burstin g of the parent tube in Ascidium (p. 128), Hy-
drodictyon ,§ Ghatomorpha cerea, || Bryopsis ;^[ through
tearing open of the apex of the tube in the genus
Derbesia ,** separated by Solier froni Bryopsis, as also in
Sctproleynia ferax, K. ( Achlya prolifera,\\ Nees.) ; by a
hole formed regularly at the upper margin of the cell in
Cladopliora by a most elegant, lid-like dehiscence in
certain species of the genus Chytridium §§ parasitical on

* Niigeli, ‘ Einzell. Algen,’ p. 84, t. iii, e.

f Ibid., p. 86, t. iii, d.

X Crouan, (‘Ann. des Sc. nat.,’ 1839, p. 248, t. v). According to
Thuret, (‘Aun. des Sc. nat.,’ 1845, p. 274), the gonidia of ihis genus have
two cilia.

§ In partieular from these cells in which no new net is formed, (see
above, page 137.

|| According to J. Agardli. (‘Ann. des Sc. nat.,’ 1836, p. 194, t. xii,
f. 1.)

Ibid., 1. c., p. 200, t. xii, f. 9.

** ‘Ann. des Sc. nat.,’ 1847, t. vii. The genas Derbesia includes Bryopsis
tenuissima and Lamourouxii of autliors, the fertile branchlets are shorter and
more inflated than in Bryopsis, they let the mass of the germ-cells escape at
once by bursting at the apex, while in Bryopsis, according to Agardh, the
germ-cells escape singly by a small, lateral, j)ipple-like and outwardly pro-
jecting orifice. The germ-ccll of Derbesia possesses a wreatli of cilia, like
thoseof (Edoqonium.

ft Vide Unger, ‘Einiges zur Lebensgeschichte der Achyla prolifera,’
(‘ Linnsea,’ 1843, p. 129, t. iv.) I have repeatedly observed the mode of
origin of the gonidia from the mucilaginous layer of the fructifying end-
celf; I could only detect a single, short cilium, while Thuret describes two.

++ According to observations on Cladopliora glomerata, (June 1847), and
fracta , (August 1847). Meyen observed the birth of the active spores in the
former species, (‘Nov. Acta.,’ t. xiv, ii, p. 445, t. xxvii, f. 5, 6.) In rcgard
to the number of cilia my observations agree with Thuret’ s ; I found two in
C. glovierata.

§ § The Chytridia form a new genus of unicellular, parasitical Alg£e, or, if it
be preferred, of aquatic Fungi, related to Saprolegnia abont as much as
Ascidium is to Bryopsis. The cntire plant is composed of a siugle, balloon-
shaped cell, which penetrates into the Algai upon which it grows bv a more
or less dcveloped root-like base. The mflatcd portion of the cell is Glied
with colourless mueilagc, from which are formed, not through successive

186

THE PHENOMENON OE

otlier Algse. In several of the last-named genera, an
active whirling motion of the gonidia occurs, even inside
the mother-cell, as especially in Ascidium, Hydrodictyon ,
Chmtomorpha cßrea, Bryopsis , and Cladophora ; in Der-
be&ia, Saproleynia, and Chytridium, on the contrary, the
motion does not become evident until after the birth of
the previonsly crowded germ-cells. In Phormidium,
Lynybya , Scytonema , Tolpothrix, Calotlirix, Masticho?iema
(see p. 147), and otlier allied genera, longer or shorter
filiform pieccs of connected, motionless gonidia are seen
to emcrge gradually from the sheaths common to the
whole rows of cells, and open above, breaking-up into
the separate joints after they are set free. Here, as in
all the preceding cases, it is donbtless the elasticity of the
walls vvliich effects the expulsion of the germ-cells ; the
bursting of the mother-cell coats is caused either by the
turgidity of the germ-cells, or if these do not wholly fill
the cavity (as in Ascidium , Hydrodictyon, and Cladophora),
by increased absorption of water after previons softening
of the cell-membrane. We see the effect of elasticity
most clearly in the well-known smoke- or cloud-like
explosion of the spores in certain families of Fungi, espe-
cially in Helvella* and Peziza, f in which the rows of
eiglit spores are cast out with great force from the
clavate or fusiform parent-tubes, forming the thecal
membrane ( Hymenium ) of these Fungi.

division but by a simultancous process, very uumerous small globular germ-
cells, •which exhibit a sharply-defincd darker uucleus in the interior, and
possess a single very long cilium. From their want of colour, and the
activity of their motion, these gonidia resemble the most minute monads.
Their extrusion occurs either through the Casting off of a lid, or through
mere tearing of a nipple-shaped point. Of fifteen different specics which I
have obscrved in the vicinity of Freiburg, Ch. olla is the largest, and at the
same time exhibits the lid-lfkc dehisccnce most beautifully; it grows on the
anterior wrinkled end oftlie bulging parent-cells of the spores of (Edogonium
Landsboroughii, the root peuctrating into the f'olds and attacliing itself to the
spore. The free inflated portion of the cell is ovate, with the lid somewhat
thrown up at the edges and apiculated like a short nipple in the middle.
The germ-cells are about 353 millim. in diameter. ^

* Yide Bulliard, ‘ Champignons de la France, 11, t. 242.
f Ibid., t. 154, and Corda, ‘ Icones Fungorum,’ 111, t. vi, 95. (Also
Tulasne, "Ann. des Sc. nat.,’ 3e sdr., xvii, 72.)

REJUVENESCENCE IN NATURE. 187

I will add to these examples of the aetting-free of the
cells destined for the Rejuvenescence from tlieir “ super-
annuated” envelopes, a few very stränge examples of
normally imperfect release of the germ-cells. I have
applied the name Sciadiim* to a minute Unicellular
Alga, which displays an originally obovate tube, gradually
becoming elongated into a cylindrical form, obtuse above,
and prolonged into a slender attaclied pedicle below.
The contents consist of uniformly green mucilage, in
which a small vesicle may sometimes be distinguished,
but only in the earliest stage of growth. The pedicle is
transparent and colourless, and secretes at its base an
originally yellowish-brown, afterwards dark-brown mass,
which gradually expands into a disk-shaped foot. When
the growth is completed, the green contents become
divided into several masses, developing into a series of
b- — 8 germ-cells; the cell-membrane dehisces, throwing
off its summit as a finger-stall shaped cover, but the
germ-cells instead of leaving the opened tube, all collect
at the point of exit with their inferior, narrower, and
somewhat pedicellately elongated ends sticking in the
tube. Thus is produced a capitule, and by the advancing
growth of the young family, an umbel formed of indi-
viduals exactly resembling the parent individual from
which they originated. The emptied mother-cell tube
remains as the stem and support of the umbellate family,
and gradually becomes filled from above downwards with
the same yellow and reddish-brown secreted substance,
which it exhibits at its own base. The imperfect birth
of the germ-cells just described, is repeated at the transi-
tion to the third, and mostly even to the fourth gene-
ration, so that little arborescent groups are produced,

* Vidc Kiitzing, ‘Sp. Alg.,’ p. 490, who places t.his little plant in the
neighbourhood of Bryopsis. To me, Ophiocytiim , Niig., (‘ Einz. Alg.,’
t. iv, a), seem the nearest allied genus ; young specimens completely
resemble Characium and Ascidium. The onlv species, Sc. Arbuscula , occurs
near Freiburg on various filiform Algte, especially on (Edogonium Lands-
boroughii aml Vaucheria racemosa, in the water rcservoirs of the Botanic
garden.

188

TUE PHENOMENON OE

with twice or thrice repeated umbellate ramification, tili
at length the cells which form the outermost umbellules,
scatter out their germ-cells, which, after a short swanning,*
fix themselves again to be developed into ramified Stocks
of new families. Nägeli has described another case of
ramificatiou through imperfect birth of germ-cells, in the
genus Vcdonia. f I have observed a still more wonderful
mode of imperfect birth in Saprolec/nia capitulifero. j
The formation of the fruit-clubs and germ-cells takes
place as in S.feracc , only the formation of the fruit-clubs
is never repeated by the elevation of the bottom and
growing-through of the fmit-club, but by the formation
of opposite, divergent lateral branches, close beneath it.
The fruit-club, as it is called, i. e. the cell cut oft“ from
the remainder of the stem, from the contents of which
the germ-cells are produced, finally opens at the apex,
and the germ-cells (40 or 50 in number) move actively
towards the mouth, in front of which they make a halt,
and, crowding up closely together, form a globular capi-
tulum. I could not clearly make out what really kept
tliem back here. But the duration of this capitule is
very short, for within only a few hours the germ-cells
leave this, their first Station, slipping out of a mem-
branous coat, probably formed during their period of rest,
and swanning again for a short time after this skinning.
All that remains of the capitules is a collection of empty
vesicles, unless a few germ-cells accidentally remain
sticking in tliem, wlien thesc immediately begin to
germinate, sendin g out an acute tubulär process.

It scarcely requires to be mentioned, that the phe-
nomena of mechanical release from “ superannuated”

* Tlie swarming germ-cells of the last generation appear to possess two

' + Nägeli. ‘ Algensyst.,’ p. 156, t. ii, f 12-14.

Kützing, ‘ Spec. Alg.,’ p. 160. The observations were made in August
and September, 1847, 011 specimens from the lili Sea in the Black l'orest;
which vegetated luxuriantly 011 decaying pieces of Nuphar pumilum ( Spenneri -
anuni), but which also rapi'dly attachcd themselves upon flies fallmg into the
water.

RKJUVENESCENCE TN NATURE.

189

envelopes obstructing the further development or reju-
venised formative action, such as we have here examined
in the life of the cell, ave repeated in the compound
organism of the plant. Thus we see that the first leaves
and roots of Marsilia and Pilularia break through the
tissue of the proembryo, the first roots of most of the
Monocotyledons, as well as all the subsequently appearing
adventitious roots, through thecortical tissue of thestem.
The leaves of Ophioglossum break through the cellular
cover under wdiicli they are formed ; the young sporange
of the Hepaticse breaks through its outer coat above,
leaving it behind as a sheath at the base ; the sporange of
the Mosses tears it in two at the base, and lifts it up as
the calyptra. In like manner many Agarics tear open the
veil which encloses them in their young stage. The bark
of many trees exhibits a process of peeling off. We
find a periodical exfoliation of the periderm in Bubus
odoratus, Spiro: a opulifolia, and particularly distinct in
the Birch and the Strawberry-tree ( Arbutus Andrachne)-,
a peeling of the outer liber-layers in the Vine and
Clematis ; a scaling-off of the bark in the Plane, the
Apple, the Fir, &c. The tuberous stem of Isoetes
scales off at its circumference. Finally, the emergence
of the embryo from the seed-coats in the germination of
Flowering plants, presents itself as a complete “ slipping
out.”

We now pass to another mode, in which cell-
structure advancing to a rejuvenised vital activity frees
itself from the envelopes previously formed by itself,
namely, to the phenomena of Chemical softening and
solution of the cell-membrane, which take place soine-
times as a swelling-up, terminating in dissolution, and
sometimes as an imperceptible resorption. The change
of the cell-membrane into a more or less fluid jelly
which is at length wholly dissipated, at the advent of the
series of generations, is a very frequent phenomenon
among the lowest groups of the Algrn, as, for instance, in

190

THE PHENOMENON OE

the families of the Palmellaceae,* Chroococcacese,f Nos-
tochinese, &c., only unfortunätely we are very deficient in
satisfactory investigations into tliese gelatinous struc-
tures, both in morphological and Chemical respects. While
they were formerly mostly regarded as excretions through
the cell-walls (extra-cellular substance), Nägeli, j if I do
not misunderstand the passage, explains them as outer
layers of the ccll-wall itself, under the name of enveloping-
membrane (Hüll-membran) .

In Glaocapsa, Gleeocystis, and the other examples
mentioned above, this explanation seems to me undoubt-
edly correct, while in other cases the gelatinous mass
appears to be a real secretion on the surface of the cell-
membrane ; as, for instance, in the gelatinous envelope,
which, according to Thwaites, surrounds the conjugated
individuals of the Diatomaceae, or the amorphous, very
fluid jelly in which many of the Desmidiacese live, as, for
instance, Penium curtum, the individuals of which undergo
the “ skinning” above described, in their division,^ inside
this jelly. In many cases thcse gelatinous envelopes
appcar not so much like altered and swollen layers of
cell-membrane, as coats originally secreted in a fluid-
gelatinous form. At the saine time undoubted cases
sliow that a gelatinous softening, swelling-up, and final
solution of cell-membrane, formed of cellulose of normal
character, does really occur. My observation s on the
frequently mentioned Water-net ( Plydrodictyon ), afford
an opportunity for a minute description of such a process.
The cells of this plant exhibit, in their full-grown condition,
a tough and firm cell-membrane, about ^th millim. in
thickness. By close examination, we may distinguish
tliree layers in this, the outermost of which is the thin-

* Vide, for instauce, Palmelia, (Nägeli, ‘ Binz. Algen./ t. iv, n.)
f Ex. gr., Glceocapsa, (ibid., t. i, r,) Äphanocapsa, (t. 1, B,) Glmthece,
(t. i, g), Aphanothece, (t,. i, n.)

X ‘Einzell. Alg./ p. 13.

| Yide supra, p. 181.

REJUVENESCENCE IN NATURE. 191

liest, the middle the thickest ; both the inner layers are
colourless, the outermost is of a pale yellow tint. When
treated witli dilute sulphuric and tincture of iodine, tliey
exhibit different behaviour. The extern al layer, which
I shall call the cuticle, neither swells np evidently, nor
becomes coloured; the inner two, on the contrary, acqnire
a violet colour, more or less intense according to the
circumstances, and swell up, so that the membrane as a
whole appears twice or thrice as thick as at first, The
innermost layer here becomes. thicker than the middle
one, which was previously the thickest, at the same time
becoming folded in waves on its snrface, and allowing us
to make out clearly a composition out of two suborclinate
layers. If strong sulphuric acid is applied, the circum-
ference of the entire cell is perceptibly contracted ; the
cuticle, however, does not share in this diminution of
size, but gradually separates, forming numerous wavy or
vesicular elevations, from the inner layers of the cell-
membrane, under which circumstances it can be readily
ascertained that it extends over the surfaces of articulation
of the cells, and therefore completely encloses the indi-
vidual cells, like the inner layers. A long-continued
action of strong sulphuric acid dissolves the cell-wall, the
cuticle however appearing to withstand this longer. A
swelling-up of the cell-membrane, exactly similar to that
produced artificially by acids, takes place in the natural
course of life of the Water-net, at the periocl of
propagation. As soon as the germ-cells are formed in
the interior, the cell-membrane appears thickened, and
its internal surface somewhat wavy. While the spores
are commencing their originally very slight movements,
the cuticle tears. From this time those cells in which
large gonidia, destined to form new nets, have been
produced, are distinguished from those which contain
small gonidia destined to swarm out.* In the former,
namely, the entire cell-membrane expands very perceptibly
and uniformly in the course of a few minutes, the cuticle,

* Yidc supra, p. 137.

192

THE PHENOMENON OF

now too small, being peeled off in little strips By this
expansion tlie cell -mein brane is removed to a little dis-
tance from the layer of macrogonidia previously lying close
upon it, and these, now gaining space, commence a more
active tremulous motion, soon uniting together into a
new net inside the mother-cell membrane, and in this
combination settling to rest. The young net enclosed
by the membrane of the mother-cell now grows rapidly,
the mother-cell membrane continues to expand for a
short time longer, becoming at the same time continnally
less distinct, and by the second day it has entirely
vanished. In those cells, on the other hand, containing
microgonidia, the cell-membrane does not expand nni-
formly, but forms a bulging enlargcment, at one or other
part where the cuticle is torn, which bnrsts and lets out
the microgonidia in a dense swarm, moving most actively.
Emptied by the swarming out, it remains unchanged,
and" is for a long time distinguishable as an empty coat,
a proof that the more rapid solution of the net-forming
mother-cell is produced by internal causes. Other cells
which do not arrive at fructification, never exhibit the
process of softening. While, under favorable circum-
stances, the entire process of Vegetation of the Ilydro-
dictyon net is completed in 3 — 4 weeks, in which
time the individual cell is enlarged (longitudinally) more
than a hundred-fold (sometimes even 4 — 5 hundred-
folcl)-, — other nets, in unfavorable conditions, exhibit
a slower development, vegetating for four or five inonths
without attaining the normal dimensions. ln the cells
of such retarded nets, never attaining to fructification,
we observe a proportionately thicker and very firm cell-
membrane, which exhibits in the sectional view a delicate
transverse striation (pore canals ?) which I never could
detect in normally developed cells.*

* (This striation seems analogous to that sometiroos occuning in lihci -
cells of certain Phanerogamia, as first describcd by Schacht. See a notice
ou this noint (by the present translator) in the ‘ Journ. of Microsc. Science,
vol. i, p. 233, (1853.) — A. H.)

REJUVENESCENCE IN NATURE.

193

The contents of these cells raostly exhibit an abundant
formation of oil, of which scarcely any perceptible trace
otherwise occurs, and tbey decay finally witli various
phenomena of dissolution ; but the cell-membrane is still
firm and uninjured after the death of the contents. All
this proves beyond doubt the relation of the softening and
solution of the membrane to the processes of Rejuve-
nescence in the contents of the cell. A similar softening
and solution of the cell-membrane occurs in Botrydium *
at the period of formation of the germ-cells. The vesicle,
of a leek-green colour at the time of the vegetative com-
pletion, assumes a sea-green colour at the period of
ripening, which results from the thickening and clouding
of the cell-membrane which occurs at this time ; the
previously indistinguishable laminated structure of the
membrane becomes clearly visible about this time, and
the cell-membrane, become limp by softening, collapses,
finally melting away, and leaving the germ-cells behind
upon the ground. The solution and resorption of the
parent-cell membranes, so frequently occurring in the
tissues of plants, which have been most accurately observed
in the formation of the spores of the Ferns and Mosses,f
as also in the formation of the pollen of the Phanerogamia,
undoubtedly depend upon similar processes. The gela-
tinous thickening of the membrane of the mother-cell
mentioned both by Nägeli]: and Unger,§ is probably
intimately connected with the quickly succeedina; re-
sorption.

We may also again call attention here to analogous
occurrences in the compound structure of the plant. As
the old envelope of the individual cell becomes softened
and dissolved, and vanishes imperceptibly, in the trans-

* A^® suPrai P- 128. My observations were made on the smaller
species ol this genus, B. Wallrotliii , Kütz.

f t or the latest reseaches on this head, see Hofmeister, 4 Fruchtbildung,
&c., der hoher. Kryptogamen,’ 1850.

+ ‘ Zur Fntwicklungs-gcschichtc des Pollens der Phanerogamen,’ 1842.

\ a ^e®er Merismatische Zellbildung bei der Entwicklung des Pollens,’
1 844.

13

194

THE P1IEN0MEN0N OF

formation advancing to a new individualisation, so are
the compound masses of cellular tissue, which do not
themselves become rejuvenised, but enclose parts in
process of Rejuvenescence, clissolved and destroyed.
Thus, in the development of the seed of the Phanero-
gamia, the envcloping tissue of the nucleus (the axis of
the ovule or seed-bud) is first resorbed in mass, as the
embryo-sac increases in size ; soon afterwards», the tissue
formed in the embryo-sac, the albumen or endosperm
surrounding the embryo, is again eit hör wholly or
partially consumed, while the embryo enclosed by it,
advances in its development inside the seed. A similar
process takes place again in germination, for in albumi-
nous seeds a softening and solution of the albumen takes
place at this pcriod. We find examples of a gelatinous
swelling up of very thick-coated albumen-cells, at the
period of germination, especially in many Palms ( Phoenix ,
Manicaria , P hytelephas ), and many Leguminosse ( Cercis ,
Caihartocarpus, Ceratonici, Gleditschia, Tamarindus,
Bauhinia, Parlänsonia , Dialium, Mimosa, &c.) A similar
gelatinous unfolding of the cells occurs also in the internal
layer of cells of the testa (the epithelium of the seed), as,
for instance, in the quince and many Cruciferae. The
rcmarkahle expansion of certain layers of cells of the spore-
fruit of Marsilia , producing at the dehiscence of the fruit
the gelatinous mass issuing in the form of a long worin, oh
which are attached the likewise gelatinous indusia en-
closing the individual sori, also deserves mention here.*
While the phenomena of putting oft' the old clothing
of the cells, examined up to this point, have displayed to
us only the external side of the process of Rejuvenescence,
the consideration of the phenomena of solution, through
which the newly-shaped products are prepared in the
contents of the cells, must necessarily carry us deeper into
the essence of Rejuvenescence. The process of solution and
transformation in the contents of the cell , invades more or

* ‘ Explor. Scientifique d’Algerie,’ Bot., t. xxxviii, f. 24-26 ; Schnizlein,
1 Iconographia.’ Marsilcacefe, f.

REJUVENESCENCE IN NATURE.

195

less all parts of these ; we see it most clearly in the
behaviour of starch or of amylon , of the fixed oils, as also
of the nucleus. There are certain products of cell-life
which furnish a measure of the age of the cell. While
the formation of Chlorophyll is especially proper to the
more vigorous youth of the cell, we see in the formation
of starch and oil, in the interior of the cell, just as in the
formation of cellulose-layers upon its surface, the com-
mencement of a limitation and quieting of the vital
activity, which marks the more advanced age, with the
distinctiou, however, that the preponderating formation
of cell-membrane (the process of lignification) usually
results in the permanent deatk of the cell, while the
filling of the cell with starch or oil brings with it a
condition of sleep, from which it may awake, under
certain circumstances, even after thousands of years, as is
proved by the well-known experiments on the germination
of grains of wheat from the tombs of the Egyptian
kings. This is more particularly true of the condition of
rest produced by formation of starch, while the formation
of oil, although frequently, is not always accompanied by
a condition of the cell in which it is capable of Rejuve-
nescence.

The formation of Chlorophyll Stands in inverse pro-
portion to that of starch and the fixed oils, in the cells ;
while starch and oil appear in greatest abundance in the
old age of the cell, and are again either wholly or partially
destroyed in its Rejuvenescence, the green colouring
matter, on the direct reverse, vanishes in the old age of
the cells, reappearing in their Rejuvenescence. Thus the
leaves of the ivy are coloured more or less with brownish
red in winter, and grow green again in spring. The
embryos of many sceds are green in the earliest period of
formation, but as the seed ripens, passing into the stage
of sleep, they become white, from the Chlorophyll dis-
appearing and the cell becoming filled with starch or oil,
tili finally, in germination, awakening to new life, they
again acquire a green colour. The contcnts of the spores

196

THE PHENOMENON OF

of many Cryptogamia also include Chlorophyll before
they are mature, but lose the Chlorophyll, and become
yellow, brown or red,* * * § through formation of oil, or
white, f through formation of starch, in ripcning ; tili at
length the Chlorophyll reappears in the germination.
Chlorophyll, however, this green colouring matter of
plants, so characteristic of the Vegetable kingdom in its
total manifestation, so intimately connected with the
independent^ vegetative process, is one of the vegetable
substances which has hitherto been least subjected to
accurate investigation, in reference to its Chemical con-
ditions, its gcnetic connection with other substances of
the cell-contents, and its transformations ; nay even in
reference to the shapes in which it occurs, either alone or
combined with other substances, in the cell, — so that
wc are compclled to rest satisficd with tliese brief
indications.§

Wc will trace more in detail the play of formation,
solution, and reformation in the contents of the cell, in
the phenomena exhibited by starch. Schleiden calls
starch the most widely diffused substance in the Vegetable
kingdom, saying that he is not acquainted with a single
plant which does not contain more or less starch at some
season or other, at all events at the period of the rest of
vegetation.|| This particular occurrence of starch at the
period of resling Vegetation, in the organs in which the
plant preserves its life for a future season of Vegetation,

* Yide the spores of Vauclieria, Spirogyru, (Edogotiium, Bulbocliccte , &c.
According to Mold, the spores of Jungermannia contain Chlorophyll in
youtli (correct, A. H.). In Chlamidococcus pluvialis, the green colour
vanishes entirely in the resting generation (the seed-cells, spores) which
become reddish-brown or bright red ; the activc generations ( gonidia ), on the
contrary, gradually become green again ; (see farther on.)

+ Thus in the spores of Characeaj.

| It is absent, as is well known, from most parasitieal plants, Crypto-
gamia as weil as Phanerogamia.

§ (On the i

des Sc. nat.,’ - - , . . _ . . , , , „ . _ , . . ,

|| ‘ Grundzüge,’ 2te Aufg. 1, p. 180, (‘ Principles, p. 18.) Schleiden here
forgets to mention the Fungi , in which, as in the fungoid Phanerogamic
parasites, starch-formation a'ppears to be absent. In the Phycochromiferous

Anu.

REJUVENESCENCE IN NATURE.

] 97

during tlie period of rest (the winter or summer sleep),
points to the destinatiou of starch in the economy of
vegetable life. Tlius we find starch deposited in especial
abundance in tuberously thickened roots (<?. g., Curcuma
leucorhizä), in the subterraneous stolons forining propa-
gation-tubers (potato), in perennial rhizomes {Iris, Arum,
Isoctes*), in subterranean buds and bulbs (Liliacese), in
the seeds of the Phanerogamia, either in the albumen
(Graminacese, Polygoneae, Chenopodiaceae), or the em-
bryo (Leguminosae, Castanea, JEsculus ), and also in the
spores of many Cryptogamia (<?. g., Characeae and
Rhizocarpeae). We find some starch deposited even in
the bark and alburnun of trees in the winter. At the
re-awakening of Vegetation a new formative activity
sometimes presents itself in these same organs and the
sarae cells, as in the embryo and spores awakening from
the seed-sleep ; sometimes the tissue filled with starch is
merely subservient, preparing nourishment for other
organs in course of development, by the process of
solution taking place in it, dying away itself after ful-
filling this destination, as is the case in the albumen of
seeds, the tubers of the potato, the thick cotyledon of the
chesnut. 13ut the occurrence of solution of starch is
not confined merely to such Rejuvenescence connected with
the changes of the seasons : I have observed it oftentimes
in the Algse in the midst of summer, and without a
preceding period of rest, in progress of transition to
propagation, in particular in the preparatory stages of
the formation of gonidia. Hydrodictyon exhibits the fol-
lowing phenomena in this respect. The grains of starcht
form in g gradually in the course of the period of growth
of the net, make their first appearance as minute globules
(or vesicles?) from ^th to ~th of a millim. diameter, of

Algic, (Chroococcaceaj, Oscillatorinece, Nostochineae, &c.), both starch aiid
Chlorophyll are deficient. (Nägeli, ‘Einz. Alg.,’ p. 5.)

* In the cake-sliaped rhizome of Isoiiles lacustris there is an abundant
quantity of starch, but ouly slight traccs of oil, whilc in the rhizomes of the
terrestrial species there exists a preponderance of fixed oil ; (see p. 200.)

t Sec above, pp. 172, 192.

198

THE PHENOMENON OF

higher colour than the snrrounding green mass, which
exhibits the deepest colour immediately around them. I
could not observe how these first globules, or vesicles,
originated in the green mass ; the first of them displayed
itself immediately after the gonidia uniting to form a net
liad passed into a condition of rest, before the cavity of
the cell had become excavated, and witli each succeecling
day appeared new ones, which did not seem to liave been
formed by division of the first, but to liave an inde-
pendent origin. Even by the second day these vesicles
were found surrounded by a more or less evident border,
originally green, and witli a somewhat sinuous or denti-
culatcd outline, but soon assuming the shape of an
accurately defined, exactly circular envelope. The larger
globulc originating in tliis way was from r^tli to ^th
millim. in diameter, and did not subsequently increase in
size ; it exhibited a yellowish or light yellowish-green
colour, the nucleus (the globule first formed) always ap-
pearing somewhat lighter than the envelope. On applying
tincture of iodine, these globules assumcd a violet colour,
the nucleus seeming to me lighter, more of a wine-red ;
after a previous bleaching, by keeping a longish time in
alcohol, the envelope was colourcd darker, the nucleus
paler blue-gray ; by a stronger action of iodine, so dark
tliat the colour was no longer distinguishable. On the
application of solution of caustic potash, the envelopes
swelled up to about three or four times the diameter,
and finally vanished entirely, whilethe nucleus remained
unaltered.* No lamination could be seen in the swelling
coats. Thus it cannot be doubted that the envelope,
originally infiltrated with Chlorophyll, was composed, in
its fully-developed condition, of starch, while the starchy-
nature of the nucleus remains very doubtful. The
described mode of formation of the starch-granules of
Ilydrodidyon appears to tally better with the theory of
Eritsche and Schleiden, that the concentrically striped

* Whether or not the nucleus would dissolve by longer action of potash
requires a repetition of the invcstigation.

REJ UVENESCENCE IN NATURE.

199

starch-granules originate by external formation of layers
around a nucleus, than with that set up by Munter and
Nägeli, of an inner (centripetal) formation of layers.*
Examining the behaviour of these starch-grains at the
commencement of propagation, we find them disappear
in the inverse order of the origin of their parts, the
envelope first dissolving, the nucleus remaining distin-
guishable for some time, tili at length this likewise
vanishes without leaving a trace. This entire process of
solution is ordinarily completed in one night ; the forma-
tion of the gonidia and the above-described softening of
the cell-membrane follows at its heels. I have observed
an exactly similar disappearance of the starch-granules
shortly before the commencement of the formation of the
gonidia in Cladophora glomerata , the cells of which, as
in Hydrodictyon , contain a great abundance of starch-

* Schleiden (‘ Grundzüge,’ 3te Auft., p. 187, Transl., pp. 11, 507) ; Miiuter
(‘ Uber das Amylum der Gloriosa superba,’ &c. ; ‘ Bot. Zeit.,’ 1815, p. 198) ;
Kägeli (‘ Zeitschrift,’ 1817, p. 117). In spite of the many researches upou
starch we possess, the origin and development of the starch grain requires
a new and carefül investigation, since none of the views hitherto put forth
are sufEcientlv supported by direct observations. The tlieory of centripetal
lamination is apparently borne out by the greater softness of the inner
layers, but I would suggest that the cavity of the concentric starch grains
is always so small that, taking into account the enormous eniargement which
the starch grain undergoes during the formation of the layers, an expansion
of the outer layers after their formation must be assumed, such as is
scarcely conceivable. The small starch-granules which so frequently occur
among the layers, seem to possess no cavity at all; in the sometimes single,
sometimes associated starch granules found so frequently in the interior of
Chlorophyll vesicles, (I found 10 — 12 of them in one chlorophyll-vesicle of
the uppermost foliar joints of Cliara hispida ), no trace of a cavity can be
distinguished. Hence the conjecture may be admissible that the cavity in
the larger granules is not an original but a secondary phenomenon, resulting
from the disappearance of the nucleus. If the starch grains are not cells
themselyes, but bodics secreted by the cell-contents, like the cell-membrane,
with which they are so closely allied chemically, thin concentricul formations
from the Outside is by far the more probable. I would compare their origin
with that of pearls in the oyster shell, disregarding of course the accidental
character of the latter. As many pearls, wlicn in contact with their shell,
bccome covered up by the later lamellse of the shell, structures resembliug
starch grains occur in Hydrodictyon , as abnormal formations, encloscd
between the lamella; of the cell-membrane. I shall describe these more
minutely at another opportunity, together with other stränge structures
occurring in the cell-membrane of Hydrodictyon.

200

THE PHENOMENON OF

granules ; also in Ulothrix , where the cells contain about
six, and in Ascidium and Pediastrum, where the cells have
only a single starch-grain. In Chlcimidococcus the starch -
grains vanish at the commencement of the division of the
active cells (to be described hereafter).

The formation of fixed oil is intimately connected with
that of starch in the economy of cell-life ; its appearance,
in like manner, announces the repose of age in cell-life,
its disappearance the beginning of Rejuvenescence. We
meet with fixed oil in the cells, either mixed with starch, .
substituted for it, or gradually displacing it ; its occur-
rence is perhaps still more general than that of starch,
since it cxists even in the Fungi and Phycochromiferous
Algae. Like starch, it is met with in greatest abundance
in tliose parts in whicli Vegetation is destined to rcst, and
to await. a futurc re-awakening, for instance, in tuberous
stolons ( Cyperus esculentus) and rliizomes ( Isoetes ,* * * § Axpi-
dium Filix man.) ; in the seeds of the Phanerogamia,
either in the albumen ( Euphorbia , Umbclliferuc, Vitis),
or in the embryo (Crucifcrae, Compositae, Cucurbitaceae,
Amygdaleae, Juglandeae) ; in the resting spores of Ferns,
Lycopodiaceae, Mosses,t Hepaticae,! Lichens, § and many

* Especially in the terrestrial species : I. liystrix , Durieu ; and I. duricei,
Bory, (‘Explor. Scient. d’Algeric,’ Bot., t. xxxvi), as also those which
grow on spots only overflowed in winter, as I. setacea, Bose., I. adspersa ,
A. Braun, I. velata, A. Br., (ibid., t. xxxvii). All tliese contain only a little
starch but a great abundance of fixed oil, in the short tuberous stem, wliilc
our always aejuatic I. lacustris exhibits but little oil with abundance of
starch. The oleaginous Isoetes all have the power of surviving a long time
in a perfectly dry condition. I. liystrix and Duricei grow upou the dryest
hills of Algcria, in loose sand, close to the surface of the ground, where tliey
are exposed during eight or uine months to the greatest drought and the
most burning licat of the sun. According to the cxperience of Durieu, the
tubers of fliese species still remain alive, alter liaving been kept dried for
five or six years ; I mvself have seen a specimen of Isoetes setacea revive and
vegetate alter it had lain almost two years in an herbarium.

f According to W. Schimper, (‘Recherch. sur les Mousses,’ p. 77), the
contents of the spores of Mosses are oily, without a trace of starch.

X According to Mohl, (‘Yerm. Schrift.,’ pp. 87, 90), the developing spores
or Antlioceros contain starch-grains, while the ripe spores contain only a
mucilaginous fluid in which oil-drops are intermixed.

§ The spores of (he Lichens (Mohl, ‘Yerm. Schrift,’ p. 75) offen contain
an oil-drop.

REJUVENESCENCE IN NATURE.

201

Algae (e. g. Vaucheria , Spiroggra, Sph&roplea, CEdogo-
nium, BulbocluEte , Cylin drosp ermum, Rivularia, Palmo-
glcea). In the spores of Characese we find a small
quantity of an offen dark-yellow oil among the numerous
starch-grains ; the large spores of Marsilea also contain
a dirty -yellow fixed oil, besides starch. That the collec-
tions of fixed oil, so frequent in tubers and seeds, are at
least partially used up as nutriment, i. e. become trans-
formed in such a manner that they may subserve the
vegetative processes oyer again, is a fact not admitting of
doubt, although not yet sufficientlyexplained in its Chemical
relations. Certain experiences of the Algse referring here,
not only confirm this transformation of the fixed oil, but
also indicate that the necessity of a condition of rest for
most seeds, as well as for most tuberous and bulbous
plants, is connected, at least in part, with this trans-
formation of the fixed oils.*

In Spiroggra the green spiral bands undergo a remark-
able change in those cells destined for conjugation ; their
regulär course becomes interrupted by curvatures of
different kinds ; the beautifully toothed margins vanish ;
among and beside the simple or compound starch-grains
previously present, lying in the median line of the
bands, numerous oil-drops are found, at first very
small, but some becoming as large as the starch-grains,
which are distinguished from the latter even by their
brilliancy, but still more certainly on the application of
iodine. Through the Union of the contents of the con-

* Schleiden (‘ Grundz.,’ 2te Auft. ii, p. 432 ; ‘ Principles,’ p. 462, in the
chapter on Germination) proposes the question, “ Whence does it arise that
the conditions which can ancf must introduce a determinate process into the
embryo, are capable of remaining a long period without action P” and he
connects with this the conjecture that the cause of this phenomenon may
denend upon unknown slow Chemical processes. The observations which
follow indicate that onc of these processes must be sought for in the
gradual transformation of the fixed on 1,hrougli contact with atmospheric air,
whicli contact is brought about or eise increased by drying. The well-
known phenomenon that mauy oily seeds, for instance those of the Cucur-
bitaceae, germinate more certainly and readily aftcr liaving beeil kept dried
for a number of years, than in the first year, is certainly cxplained by this.

202

THE PHENOMENON OF

jugated cells, the continuity of tlie spiral bands is finally
wholly loosened, the originally green contents of the
spores become sometimes lighter, sometimes darker
brown, and appear densely filled with oil-drops of dif-
ferent sizes. I have neglected to examine whether or
not the few starch-grains present at the formation of
the spore are still retained when it is ripe ; at all events,
the drops of oil form the most important part of the con-
tents. The contents of the spore appear totally changed
when it is about to germinate ; the multitude of large
and small oil-drops has vanished, and the opake mucilage,
now become green, again exhibits, but indistinctly, a few
small drops or vesicles. Newly-formcd spiral bands be-
comc visible, as dark,very closely approximated, frequently
soinewhat üexuous, oblique streaks, even before the
germinating internal cell has broken through its double
envelope.* (See pp. 135 and ISO.)

The stränge formation of the spore in P almoglcea, by
eomplete Union of two vegetative cells into one single
seed-cell, has been already examined (p. 136). Düring
the gradual growing togcther and fusion of the two com-
bining cells, we may trace the formation of fixed oil step
by step. Before the beginning of the combination, the
cells are filled with finely granulär green contents, in
whicli wc see arise, during the progress of the union,
shining drops, at first very small and distant, gradually
growing larger, coining in contact and coalescing, so that
the intermediate contents almost entirely disappear, and
the eomplete spore appears filled merely with a mixture
of oil-drops of the most varied size. During this process
the colour of the cells changes from green to a light
yellowish-brown. Vegetative cells, with homogeneous
green contents, originate subsequently through trans-
formation and division of the contents of these oleaginous
seed-cells. The process of the new-formation whicli I

*

Viele Pringslieim,

Irans! ated

from tlie ‘Flora,’ 1852, in

Ami. ofNal.

REJUVENESCENCE IN NATURE.

203

liave 110t succeeded in seeing in its stage of transition,
must doubtless depend upon a complete internal disso-
lution of tlie contents of tlie seed-cell by transformation
of the fixed oil, preceding the division and external
assumption of new shape. Since Palmoglcea does not
grow in water, but on damp rocks and moss, and in its
formation of seed coincides with the commencement of
the wann and dry season of the year, it is probable that
the gradual transformation of the oil begins even in the
period of dryness, even requires the drying up as a con-
dition of this process. That which I can only express as
a conjecture in regard to Palmoglcea, is a certainty in the
following examples. Penium cur tum* is a small Desmi-
diaceous plant allied to Closterium, growing in rain pools,
which are alternately quickly filled and dried up in the
changes of weather. In late autumn and in spring many
pools in the neighbourhood of Freiburg appear filled
with bright green clouds, which are formed by the social
growth, and the very fluid, widely extended gelatinous in-
vestment of the cells. The gradual ascent of these delicate
green clouds from the muddy bottom, when the little
basins of water fill again after a dry period, presents a

* See above, p. 181. Ralfs (‘British Desmid.,’ p. 109) included tliis
little plant, discovered by Brebisson, first placed under Closterium and then
separated from it in the genus Penium, among tlie Puastra , and in the
genus Cosmarium, a mistake from which a more thorough regard to the
arrangcment of the cell-contents would liave saved him. According to
Nägeli, Penium curtum should be referred to the genus Dysphinctium, sub-
genus Actinotcenium ; it is very like the D. Reyelianum figured by him,
(‘Einz. Alg.,’ 109, t. vi, e), but differs in Ihe more numcrous green longi-
tudinal bands. The plant liere named is also remarkable for exhibiting tlie
peculiar movement of the Desmidiace® more regularly and more actively
than the other members of the family, a motion very different from that of
the Diatomace®. It is. a remarkable siglit to behold all the individuals in a
dish of water in a short time turn their long axes toward the light, and
thus arrange themselves in beautiful streaks in the gelatinous mass.
Observation with the microscope shows that it is the younger half of the
cell, distinguishable as such for a long time after division, which liere
turns toward the light. Eor tliose who believe in the animal nature of the
Desmidiace®, I will add, that the ccll-membrane of Penium is totally
destroyed by a red lieat, so lliat it is not a siliceous lorica ; on the other
hand, it remains uninjurcd wlieu boilcd in solution of potasli.

204

THE PHENOMENON OF

beautiful and peculiar aspect. The formation and sub-
sequent solution of the oil, as I have observed it in these
little plants, is not connected, as in the preceding exam-
ples, with formation of spores, but occurs in the vegetative
cells ; the formation of seed, in Penium curtum, doubtless
taking place through conjugation, has not yet been
observed. In fresh vegetating individuals the contents
of the longest cell, somevvhat constricted in the middle,
cxhibit the following character : in the middle of the cell
exists a rarely clearly distinguishable nucleus; in the
middle of each half a large globe, which Nägeli calls a
chlorophyll-vesicle, but which I found completely filled
with starcli, at least certainly in older cells. The rest of
the light-green general mass of the contents is traversed
in each half by teil to twelve darker green, somewhat granu-
lated longitudinal bands, which, seen from the apex of the
cell, appear like thickish plates, arranged radiantly around
the long axis, and United in the middle. If Penium
curtum is cultivated for a length of time in a dish of
water, all the individuals undergo a peculiar alteration,
some sooner, some later. The dark-green longitudinal
strcaks become indistinct and irregulär, tili at length
they disappear, while a quantity of lighter and more
brilliant globules appear, which, increasing in size, wholly
displace the green contents of the cell, so that the pre-
viously bright green cell at last assumes a pale, dirty
yellow aspect. Accurate examination shows that the
brilliant globules now filling the cells are not the spores,
as might perhaps be conjectured, nor starch-grains,*
but really drops of oil. Tincture of iodine scarcely per-
ceptibly alters their colour, while the two large globules
of starcli still existing in the two halves of the cell acquire
a dark violet tint. If oil of turpentine is applied to a
specimen not quite dried up, the globules of oil coalesce
into larger irregulär drops ; when more completely dried

* Meyen observed the cell of Closterinm Lumda densely filled with starcli
grains, (‘ Pflanzenph.,5 iii, 437.)

REJUVENESCENCE IN NATURE.

205

up they all clearly run together, and fill the cell in an
uniform mass, by which the two starch-grains previously
hidden araong the crowd of oil-drops, become very dis-
tinctly evident. With this condition of formation of oil
commences a stage of rest in the life of this little
organism ; the cells no longer increase by division ; the
Stimulus of light no longer produces any movement ; the
gelatinous envelope vanishes without any new formation
of jelly. Unless peculiar circumstances arise, the indi-
viduals gradually die away, entirely losin g their colour.
But if the water is allowed to dry up (as happens from
time to time in the natural habitations of this plant), and
the dried remains are again immersed in water, after a
shorter or longer period,* new gelatinous clouds rise up
afresh on the following day, in which are found a multi-
tude of new, again freshly vegetating individuals, con-
taining, instead of the former oil vesicles, homogeneous
green contents, in which the green longitudinal bands
are again soon to be distinguished. The multiplication
by division also soon commences again. That these
rejuvenised, revived individuals are not a brood originating
from spores, is shown by their size, which agrees with
that of the dried-up individuals. f

I have observed still more completely the Rejuvenes-
cence, caused through drying up, in the probably oleiferous
cells of the Chlamidococcus phwialis, already many times
referred to.J

* I haye not yet made out liow long the life can be retained in the dried
condition, in Penium cur tum.

. t. I have not unfrequently seen a filling of the old cells with drops of oil,
similar to that in Peniurn cur tum, in other Desmidiacese, in Diatomacesc,
Pcdiustrum , Conferva bombycina , and exceptionally, a3 above mentioned, in
Ilydrodictyon. In most cases this formation may end witli the dcath of the
cell ; this is tolerably certain in Pediastnm particularly,

t See above, pp. 138, 158, 184, 200. I can only indicatc here the mo3t
essential elements of the stränge history of this creature, embracing a
complicatcd alternation of generations; to trace it completely through
all its normal and abnormal complications, would rcquire a separate essay
and numerous pictorial illustrations. As the obscrvation of the many
mteresting phenomena alfordcd by this plant is by no means dilEcult,
and as it is aesirable that these observations sliould be repcated by many

206

THE PHENOMENON OF

Normal fully-developed cells of tliis multiform creature,
sometimes like a plant, sometimes like an animal, present
the appearance of globules, from ^th to ^tli millim. in
diameter, with a thick tough cell-membrane, and
granular-punctate, opaque contents, sometimes of brown,
sometimes (at other periods or in other localities) bright
red colour. In the mass of the dark contents lie hidden
several other structures, which at tliis period are com-
pletely concealed, namely 4 — 6 starch-globules, of ^th,
or at rnost ^th millim. in diameter, in which, as in those
of Ilydrodictyon, a nucleus and an envelope may be
distinguished, acquiring a dirty violet colour with iodine,
the nucleus becoming rather redder. Sulphuric acid
causes a considerable swclling up of the coat. There
also appears to exist in the centre of the cell a large,
very delicate nuclear vesicle, which, however, is so
covered up by the rest of the cell-contents, that it can
only be very indistinctly perceived, and cannot even be
clearly displayed when the contents are squeezed out.
Whcn these resting globular cells are placed in water,
they give birth, in the way already described (p. 184),
to four gonidium-like swarming cells. Even before the

persons, I venture to (lraw attention to the very widc diffusion of tliis
specics. Von Flotow, the discovcrcr of Chlamidococcus pluvialis, found
it, in the ycar 1841, in a shallow hollow in a granite slab forming tlie
foot-bridgc across the Frosch-graben, ncar Hirscliberg; subsequently (1846)
also in excavations in the granite roeks of Opitzberg, near Hirschberg,
where the rain-water collected. Dr. Mettenius found it recently, also, in
cavites of granite roeks, at Harlass, near Heidelberg. I found it for the
first time in shallow hollows of horizontal sandstone slabs, on the walls
of several bridges near Freiburg, in February, 1848, accompanied evcry-
where by a beautiful llotifcr ( Philodina rosea), and in one shady spot
associated with Maslichonema pluviale. The pastor Brunner found it last
winter iu the district of Donaueschingen, in several churchyards, in the
basins cut to hold holy water of the (saudstone) gravestones, and also in
the iron vessels fixed on the tombs for the same purpose. I found it at
Ncuenberg, in Switzerland, in the years 1844 and 1848, in the hollows
formed by ancient denudations of the calcareous roeks bordering the lakc,
and in this place of especially bright red colour. Kiitzing iudicates it also
from Bohemia (according to Corda), France (Brebisson), and Scotland
(Greville), as he regards Ecemaiococc,us Corda , Meneghini , and Protococcus
nivalis, Grev., (Scott, ‘ Crypt. Flora,5 t. 231,) as the same plant as Ecemato-
coccus pluvialis, Y. Flotow, on which point 1 do not yet venture an opinion.

REJUVENESCENCE IN NATURE.

207

commenceraent of the division of the contents by which
the latter are formed, a change begins in the colonr of
the parent-cell, the red colour retreating to some extent
from the periphery, and a yellow (soraetimes rather
greenish) border forming round the deep red inner mass.
The young swarmers also, for a short time after tliey
issue out, have only a narrow yellow rim round a dark
red middle. Düring the two to three days’ period of
movement and growth of these swarming cells, — in which
they grow to about four times the original size, changing
their obtusely ovate form, at the same time, to a re-
versed pear-shaped, apiculated shape, and forming a
delicate enclosing membrane (p. 158), — important new
changes take place in the contents of the cells. The red
colour becomes more and more concentrated into the
middle of the cell, so that a sharply defined bright red
nucleus is formed, in the inferior of which a lighter space
is often clearly perceptible, corresponding to the nuclear
vesicle above mentioned, around which the red colouring
matter forms a covering, mostlv complete, but sometimes
imperfect and interrupted. The rest of the cell-contents
have become a brilliant green, and in them may be
clearly distinguished the above-mentioned starch-globules,
as well as many more smaller green granules. The
ciliated point of the cell, often drawn out like a beak, is
colourless. This first moving generation is succeeded by
a not yet accurately determined number of similar active
generation s, populating the water for some weeks, and
often giving it a bright green colour, tili at length
universal rest recoinmences, and the cells sink to the
bottom or attach themselves to the sides. The transition
from one active generation to anotlier takes place through
a transitory resting generation of extremely short duration.
The full-grown swarming-cells finally come to rest within
their wide shirt-like envelope, and almost simultaneously
divide into two cells, which, without becoming active,
divide again into two cells. Tlius, within the mother-
envelope are produced four daughter-cells (more properly

208

THE PHENOMENON OF

grandchildren), which begin to move soon after they are
completely formed, and, tearing open the delicate en-
veloping vesicle, part Company. The whole of this
process of development is gone through very rapidly,
being completed in one night and the succeeding
morning. The second active generation, thus formed,
resembles the first, with the single distinction that the
active cells are green from the first, and have a smaller
red nucleus in the interior. The subsequent active
generations bear a general resemblance to the preceding,
but many modifications present themselves. Thus, for
example, we not unfrequently see the full-grown swarm-
cells assume stränge two-lobed, or even four-lobed, shapes,
beginning to divide before they come to rest ■, or some-
times a transverse construction and bisection of the cell
takes place, caused by a partial protrusion of it. from the
loose shirt, &c. The formation of cavities (Yacuoles) is a
pretty constant phenomenon in the later active gene-
rations, and there may bc several of them eccentrically
placed, with the red nucleus rctaining its central position,
or a single central vacnole, causing a lateral displacement
of the red nucleus. If water-cavities of this kind displace
the green mucilaginous layer entirely, in places, so that
they come in contact with the primordial utricle, the
form is produced which Von Flotow called Ilcemalococcus
jjluvialis lacunosus, and has represented in pl. 25, figs.
09 and 70, loc. cit. The red nucleus offen becomes very
small in the last generations, so that it very much
resembles, especially when rendered parietal by the
formation of a central vacuole, the red corpuscle occurring
in the gonidia of many genera of Algae, belonging to
very diverse families, and which was called the “ eye”, in
the Volvocinese, by Ehrenberg.*

* I have observed an “ eye” of this kind in the swarming gonidia of
Ilydrodictyon , U lothrix zonutci , ( vide Kütz., ‘ Phyc. gen., t. lxxx,) Uloth.
Braunii, K., Hormidium variabile, K., Braparvaldia, Stigeoclonium , (in
several spccies,) Chcetophora , (likewise many,) Colcoclucte pulv'wata, Clado-
phora glomcrata ; therefore in genera belonging to live different families, not

REJUVENESCENCE IN NATURE.

209

A total disappearance of the red colour not unfrequently
occurs. In the later stages of the cycle of generations
arrives, finally, the formation of microgonidia, already
mentioned (p. 138); many individuals, instead of pro-
ducing four daughter-cells, undergoing further division,
so as to give birth toa brood of sixteen or thirty-two minute
cells, which, before they separate, form a mulberry-like
body, but, separating at length, commence a very active
swarming inside the parent envelope, terminating in the
rupture of this coat, and the rapid dispersion of the
little “swarmers.” These are of longer shape than the
large “swarmers,” only about — th, rarely ^th millim.long,
of yellowish or dirty yellowish-green colour, with reddisli
ciliated points.* They do not exhibit increase of size,
like the large “ swarmers,” never become coated with a
perceptible and loose membrane, and have no further
power of propagation. Most of them die after they have
settled to rest, dissolving away; others turn into little
red globules, and it is doubtful whether they can grow up
to the normal size. If we now further examine liow the
cycle of active generations is closed and carried over to
the resting Vegetation, we find that the large “ swarmers”
of the last active generation, when their growtli is
completed and they have attained the stage of rest,
instead of dividing again, remain undivided, assume a
perfectly globular form, and in the course of a few days
become clothed by a thick, closely applied cell-membrane,
while the earlier, loose, distant membrane gradually
disappears. The contents, which at the commencement

counting the Volvocinese (V olvox, Pandorina, Botryocyslis Morum ?.) tu
the genus Chlarnidomonas there are species with and others without the red
point. The red point seems to be absent in VaucheriaT (Edogonium, Bul-
bochcete, Conferva bombycina, Aphanochtete , Gongrosira , Ascidium, Characium,
Sciadium , Pediastrum, Apiocystis, Dictyosphcerium, Teiraspora, Protococcus
viridis, Glccococcus. The minute size and light colour may have caused it to
have been overlooked in many cases.

* Il&matococcus pluvialis porphyrocepalus, Von Flotow, 1. c., p. 469,
t. xxv, f. 74. I must observe, however, that I have never observed the
hammering movement of the slcnder red anterior end, there described ; the
motion was effected, as in the large swarmers, by two cilia, which became
visible by the applieation of tincture of iodine.

14

210

THE PHENOMENON OF

of the rest were all green, except the little red nucleus,
or even often entirely green, now gradually become red
again, passing from green through many tints of brown,
or of brilliant golden green and golden brown, into red.
These globular, thick-coated cells (the same as those with
which we began) behave like seed-cells or spores, passing
into a state of perfect rest. They do not exhibit any
growth, and after the membrane has attained its proper
thickness, and the contents their red colour, no further
visible altera tion takes place, so long as they are kept in
water. I have preserved them for several months in
water, without any new development taking place ; on
the contrary, they at lcngtli began to be bleached and to
die away, if they were not devoured by the rapidly
multiplying Rotifer ( Philodinci roseola). A desiccation
must take place before a new cycle of generations can
begin. This is the peculiarity to which I especially
wishcd to draw attention here. Even a short stage of
dryness renews the llejuvenising power of the resting
cells, and this is retained for a great length of time in
the dried condition, as might be deduced from the mode
of occurrence of the plant, and may also be easily proved
by artificial experiments. Perfectly dry specimens placed
again in water ordinarily producc active gonidia the next
morning. I have made the most remarkable experiments
on this point, on specimens which Herr von Elotow was
kind enough to send me. Specimens gathered at Hirsch-
berg, in Silesia, in March, 1848, placed in water at
Ereiburg in April of the same year, exhibited new-born
active young within 22 hours; specimens dried in 1846,
in about 32 hours ; finally, original specimens obtained
from the stone slab over the Eroschgrabe in 1841, after
about three days’ soaking. These last had therefore
retained their vital force durin g a preservation of seven
years in an herbarium.* In order to complete the main
features of the picture of the alternating generations of
this multiform creature, I must notice that, in addition
* See Yon Flotow, in regard to this, 1. c., p. 500.

REJUVENESCENCE IN NATURE. 211

to the described active generations (raacrogonidia and
microgonidia) and the concluding generation passing into
the spore-like condition of rest, there are other gene-
rations which, as compared with the gonidium-like and
spore-like conditions, must be regarded as the proper
representatives of the vegetative development. These
are generations endovved with quiet and slow vegetative
growth, which multiply by pure vegetative division,
unaccompanied by any swarming movement. It depends
solely upon external conditions whether the resting-cells
which 1 have characterised as seed-cells (spores), at once
give rise to the new active generations, or to a series of
quietly vegetating generations of cells. The former is the
case when the seed-cells are totally immersed in water ;
the latter when they occur on a spot which is at once
damp and exposed to the air,* as is the case in the
native condition, especially in the milder intervals of
winter and in the damp season of approaching spring,
but temporarily also, at all other seasons, on the margins
of the little basins inhabited by Chlamidococcus as often
as they are filled by showers of rain. In cultivating it
in the house, I have but rarely observed these vegetative
generations, while in the native stations they certainly
occupy the most important place in the alternations of
the various conditions of life, as may be conclucled from
the thickness of the crusts and membranes formed
by such vegetative multiplication.f The formation and
multiplication of these vegetative generations also take
place by the division of the cell-contents, either by simple
division, the first generation being transitory, or by
double halving (apparently quartering). But the newly
formed cells do not slip out, like the young “ swarmers/’
from the mother envelope ; they remain in the same place
and position. The membrane of the mother-cell appears
to become softened, expands, and becomes gradually

* Probably in sucli cases no perfect dessication takes place,
t II cematococcus pluoialis, var. leprosus, Von Flotow, 1. c.'

212

THE PHENOMENON OF

drawn out to nothing, rather than regularly hurst open ;
it at length vanishes in some indistinguishable way, the
daughter-cells meanwhile acquiring a tolerably thick,
closely applied cell-membrane of tlieir own. The di vision
is repeated many times in tliis way, and as the cells all
remain in intimate contact, first small families, but by
degrees large conglomerates of cells, are produced. The
size of the single cells in these groups varies from ^th to
^tli millim. ; tlieir shape is not truly globular, but partly
bounded by flat surfaces, as results from the alternating
divisions according to the three directions of space. In
tliis neighbourhood I have ordinarily found the colour
light brown. If ignorant of the rest of its history,
one would be led, by the form and mode of division of the
cells, to regard thesecrusts asbelongingto a Pleurococcus*
In the same crusts occur isolated large cells, loosened
from tlieir connection witli the otliers, perfectly globular
in form, and appearing to divide no more, but to have
past again into the condition of resting spore-cells. They
are distinguished from the rest by tlieir darker contents

* In tliis condition Chlamidococcus pluvialis exhibits such a decided
vegctable character tliat the advocates of the widest extension of the
animal kingdom, if ignorant of its active condition, could hardly conjecturc
it to bc an animal being. But cven the active state of Chlamidococcus
cannot be regardedas possessed of animal life, if the swarmiug of thegonidia
of the Algai resulting from ciliary motion — which occurs from the Palmel-
laceue upwards to the Fucoidese, and also lias its analogue in the higher
Cryptogamia, (Characeaj, Mosses, Berns, and Rhizocarpese) in the move-
ment of the spermatozoids, likewise produced by delicate cilia, — is to be
regarded as a phenomenon of vegctable life, which, in spite of our ignorance
of the cause and modus operandi of tliis motion, does not seem to admit of
doubt, from the way in which it presents itself as a normal condition connected
witli the vegetative life. Although the phenomena of motion are of longer
duration in Chlamidococcus than is usual elsewhere in the swarming gonidia
of Algae, the kiud of movement is esscutialiy the same, namely, an uninter-
rupted revolution round the long axis, combined witli an advance towards
the side ofthe ciliated point. In Chlamidococcus the direction is con-
stantly to the left, as in the gonidia of l Edogonium , while the gonidia of
Vaucheria, as also the oval family-stocks of Pandorina, revolve constantly to
the right. Witli regard to the duration of the movement, Protococcus
viridis, the active gonidia of which continue tlieir swarming even in the
night, forms an intermediate link between the ordinary behaviour and tliat
of Chamidococcus and the Volvocineai.

REJ UVENESOENCE IN NATURE.

213

and thicker cell-membrane. Probably the return of these
to renewed resting Vegetation takes place by a passage
througli the series of active generations. Every shower
of rain will wash away these loose ripe cells of the crusts
of Chlamidococcus ; carried into collections of rain-water
they will soon produce the active brood, which, returning
to rest after a few active generations, settles on the raargins
of the little puddles, and then recnrs to the resting mode of
vegetative multiplication. At least this seems to me the
normal cycle of the life of these little amphibious and am-
phibolic Algse. VYhat we intended especially to examine in
these, is the appearance and disappearance of a probably
oily red colouring matter in connection with the conditions
of old age and Rejuvenescence of the cells. We found this
most abundantly developed in the resting seed-cells, ar-
rived at the entire pause of the Vegetation, we saw it
vanish almost entirely in the active generations suc-
ceeding one another in rapid Rejuvenescence, and en-
dowed with power of very rapid growth. The red
colouring matter seems to play the same part here as we
have ascribed to the formation of oil in the instances
previously examined. Since the capability of preserving
the life in the dried condition, and the necessity of the
desiccation as a preparative for future Rejuvenescence,
may be supposed to have a similar cause in Chlamidococcus
and in other minute Algse, it is not improbable that the
red colouring matter is, in this case, either itself of oily
nature, or occurs in combination with a fixed oil.* The
mode of appearance of this in the cells testifies in favour of
this assumption to some extent, to some extent, however,

* Nägeli (‘ Einzell. Algen.,’ p. 9), likewise ascribes the red colour occur-
ring in many Palmellacea;, partlv as anormal (Pleurococcus miniatus, Palmelia
mmata) partly as au abnormal phenomenon ( Tachygonium , Chlor ococcusy
Endococcui) to the formation of an orange-coloured oil in the place of the
Chlorophyll. Probably all these have the power of rctaining their life a long
time in the dried condition, in Pleurococcus miniatus, at least, I am quite
certain of it. In the crusts of Protococcus viridis , growing on walls, also,
the cells of the uppermost layers, most liable, become dried up, oftenacquire
a brovvnish-red colour, the origin of which is probably to be cxplaincd in the
same way.

214

THE PHENOMENON OF

against it, since tlie red colour does not always present
the drop-form peculiar to oil. In completely red resting-
cells the entii*e contents (with the exception of the starch-
vesicle) appear saturated with the red colour, no separate
red drops being distinguishable ; but I sometimes found
in the dishes of water in which I cultivated the Chlami-
dococcus , resting-cells (diseased ?) in which the brownish-
green contents were somewhat retracted from the tough
cell-membrane, and between the membrane and contents
long flattened drops of decidedly oily aspect and dark
yellowish-red colour had been formed. The connected
red nucleus, such as occurs especially in the active cells,
readily breaks up into many oil-like drops, as, for
instance, when diseased cells decay in water, as also
whcn they die from being dried up;* when the cell is
crushed ; as also, lastly, when sulphuric acid is applied,
which moreover gradually gives the red drops a dirty violet
colour. Oil of turpcntine, on the contrary, in recently
dried-up cells, spreads the red colour uniformly through
the whole contents, or in a greater abundance at the
circumference of the cell.

The formation of oil presen ts itself with greater clear-
ness in the slecping state of Chlamidomonas. Several
species of this genus, hithcrto included in the Animal
kingdom, but nearly allied to Glceococcus and Chlamido-
coccus, present themselves in the beginning of spring, in
such abundance tliat they produce a striking green
coloration of the water ; a few weeks later they vanish,
leaving no trace, and are not noticed again throughout
the whole year. I liave observed the circumstances
attending this disappearance in a species which I call
Chlamidomonas ohtusa. f I brought this home in the

* According to tny observatious, all active forms die when dried up. I
cannot confirm the existence of a Hcematococcus pluvialis atomarius, such as
Von Flotow thinks we may believe in. The preservation of Chamidococcus,
both in the dry and frozen state, certainly occurs only through the resting,
thick-walled form.

f Chlamidomonas (a name certainly sounding strangely in tho vegetable
kingdom) is distinguished from the genus Chlamidococcus by the closely

REJUVENESCENCE IN NATURE. ,

215

swarraing condition in April of last year. The large,
dark green swarmers, differing from other similar green
swarming cells by the remarkable truncation of both
ends, multiplied for some time longer, and here and there
produced very minute, paler and more brownish-yellow
microgonidia ; in the course of a few weeks no more
active cells could be found in the water, the full-grown
swarmers having all gradually come to rest and stink to
the bottom. The originally longish shape of the cells
had changed into a perfect sphere with the transition to
rest ; the colour of these restin g-cells, originally still green,
now gradually passed into a light yellowish-brown, at

applied membrane (not standing away from tbe contents) of tlie old swarming
cells ; also by tbe absence of tbe little starcli-vesicles in the inferior, while,
however, as is usual in most of the Palmellacese, a single large “ Chlorophyll
utricle” (starch-utricle ?) exists in the inferior. There is no central red
nuclens, as in the gonidia of Chlamidococcus, but some species have a parietal
red spot (an “eye”). The motion is effected by two cilia, as in Chlamido-
coccus. As in that genus, there is a growth of the gonidia during “ swarm-
ing,” which lasts over the day and night. There is also a formation of
microgonidia. The species of this genus are doubtless very numerous, but
the distinction of them among themselves, as well as from the swarming-
cells of many other Algae, is very dißicult without a complete acquaintance
with the history of their lives. The new species mentioned, Chi. obtusa,
occurs in the Rinne valley, near Freiburg, in sand-pits, which are occasion-
ally almost completely dried up in summer. The macrogonidia grow during
their period of swarming, from s'a to almost 3'n millim. long; they are
longish, of equal diameter on both sides, and very obtuse, almost truncated,
having a colourless place at the ciliated extremity, presenting the form of a
notch. In regard to other points, the contents are dark green, linely
granulär, with a large vesicle at the posterior extremity, a roundisk lighter
space in front of this, and no red point. They multiply by simple or double
halviug in several successive generations. Sometimes a furtker continuatiou
of the division of the full-growu macrogonidia occurs, forming sixteen or
thirty-two macrogonidia from to TJÖ millim. long, of ovate shape, and lighter
colour, tending towards brownish-yellow. The resting (seed-) cells are
globular, about millim. in diameter, at first green, subsequently light
yellowish-brown, finally flcsh-red ; they have a tough, colourless, and trans-
parent membrane. Another species, Chi. tingens, occurs in enormous
quantity in the puddles of the saudstone quarries at Lorettoberg, near
Freiburg, in the month of March, in mild seasons sometimes evcn in
«Tanuary and February. The swarming cells are smaller tlian in the prc-
ceding, T^0 to Jg millim. long, ovate, lighter green, likcwise destitute of a
red spot, and the membrane is more distinct in the old age. Increase by
double, rarely by simple halving, in the former case with dccussating
sections. I have seen the formation of microgonidia in this species also, but
not minutely observed the resting stage. (See preface.)

216

THE PHENOMENON OE

the same time a number of small, sharply defined,
brilliant globules were formed in the interior, having
quite the appearance of drops of oil. In this altered
condition the Chlamidomonada remained, exhibiting
neither growth nor increase. At the end of the month
of May, in the hope of causing a renewed development,
I allowed the dish to dry up, but it was in vain ; even
when I poured water on tliem again about a month
after, no perceptible alteration oecurred. I let the mass
dry up again, and added water again in the middle of
December following ; towards the end of December, and
in the course of January, active Clilamidomonada actually
reappeared. All the resting globules had meantime
changed colour to some extent, appearing light reddish ;
the lirst “swarmers,” also, formed by the halving or
quartering of the contents of the resting globules, and
brought to light by a rupture of the tough coat, at first
exhibited a reddish or greenish-red colour, whicli only
passed gradually into pure green, the drops of oil
vanishing at the same time. Only a small proportion of
the resting-cells came to such development in cultivation
in the liouse ; others divided, without loss of the red-
dish colour, into quietly vegetating cells connected in
groups, in a manner similar to that I have described in
Chlamidococcus ; others remained unchanged until spring,
at which time, however, 1 did not pursue the investigation
any further. Tliere is no doubt that future investigation
will detect in the Yolvocineas resting stages for the
winter sleep, similar to those here exarnined in Chlami-
dococcus and Chlamidornonas.

Collecting together the phenomena of dissolution we
have beeil exatnining, connected with the Rejuvenescences
in Cell-life, we find that it results from them, that the
development and propagation of the Vegetable organism
does not consist of a bare series of formative processes,
but that processes of de-formation or “undoing” enter as
necessary links into the course. The plant, however,
differs essentially from the animal in this respect ; while

REJUVENESCENCE IN NATURE.

217

in the intcrchanges of material of the animal organism,
formation and deformation intermix in simultaneous
occurrence, dissolving and newly shaping in the same
epoch, the two processes are more separated in the plant,
running iuto one another in periodical alternations. In
the Vegetable kingdom, as in the Animal, the nitrogenous
substances (proteine and the substances allied to it) form
the especial substratum and active medium of the vital
activity,* while the unazotised substances, rieh in carbon,
play a more passive part in the organism, on the one
hand protecting, on the other limiting, narrowing, stnpe-
fying, and even extinguishing the vital force. The
animal organism frees itself from the superabundanee of
carbonaceous substances, which it receives for the most
part already formed in its food, tlirough the uninterrupted
process of respiration, in which the carbon is destroyed
(burnt) by the aid of the oxygen derived from the atmo-
sphere, and excreted in the form of gas. It is different
with the plant; it does excrete the substances rieh in
carbon formed in the internal organism of the cell, out
of the cell-sap, not, however, destroying them, but depo-
siting them either as organic structures on the confmes of
the cell-organism (formation of membrane from cellulose,
and the allied substances, gelin, amyloid, Lichen-starch,
&c.), or it secretes them in the interior of the cell itself
as globular, frequently laminated masses (starch or
inuline), or in the form of drops (fixed oils). The forma-
tion of the cellulose membranef is especially characteristic,
in this respect, of the plant, securing to the cell-formation
of the plant, in all cases, its peciüiar separateness and
independence, however varied the mode of ultimate

* According to Payen, all young organs of plants, in tlieir earliest stages
ol development, contain a.predominance of nitrogenous substances.

f Ccll-membranes formed of cellulose liave hitherto been found in
the animal kingdom only in tlic sac-shaped cnvelopcs of the Ascidia. Sec
Schmidt, " Zur Vergleichenden Physiologie der wirbellose Thier,” (1845)
Transl. in “Taylor’s Scientific Mcmoirs Löwig and Köllikcr, “I)c la
Composition et de la Structure des Enveloppes des Tunicicrs,” (‘Ann.
des Sc. Nat.,’ 1846, p. 193.)

218

THE PHENOMENON OE

development may be. It is to this carbonaceous appa-
ratus of the cell tliat the entire structure of the plant
owes its external and internal combination and solidity ;
but it is at tlie same time the cause of the gradual
fixation of the product, the relative absence of motion,
which distinguishes the vegetable structure, in contrast
to the internally and externally more mobile animal
organism. It is remarkable that the most striking of all
the phenomena of motion of plants, the swarming move-
ment of the gonidia and spermatozoidia, occur in such
cells as are either yet without their cellulose coating, or
which never acquire one. Thus, consequently, the life of
the plant becomes fettered by the vegetative process itself ;
the continuous secretion of cellulose, and the thickening
of the cell-wall caused thereby, obstruct more and more
the intercourse with the outside, as in likc manner the
accumulation of highly carbonized deposits in the interior
of the cclhcontents obstructs the internal movement.
Thus all vital activity must at last come to a pause,
unless this entombing and suffocating process of formation
becomes opposed by a dissolving and emancipating pro-
cess. It is just this which we liave sought to examine
in the foregoing pages ; we have seen it make its appear-
ance at a definite period in tliose parts which aredestined
to carry on or repeat the development, dcstroying pre-
ceding constructions, and making space for new forma-
tions, more or less interrupting the old course of com-
pletion, and often causing the life to turn off in new
directions. We liave seen that the solid cell-membrane
becomes soft again, bursts, or dissolves away ; we have
seen the starch dissolved, the fixed oils vanish. But the
most important occurrence in this process of destruction
is not merely a solution of that which had become solid,
not merely a process of transformation of the substances
secreted in the formative process, into new material for
structure (<?. y. starch into dextrine and sugar), but, at
all events in part, an actual destruction (combustion)
of the highly carbonized substances present in excess,

REJUVENESCENCE IN NATURE.

219

similar to that which occurs in animal respiration. It
is well-knovvn that in the germin ation of mealy seeds, as
also in the sprouting of mealy tubers, an abundant ex-
cretion of carbonic acid is associated with the conversion
of the starch into sugar, and that tliis, connected with
perceptible evolution of heat, is caused by a decomposition
of sugar; it is well-known that beets and carrots lose
the sugar they contain, at the period of the unfoldmg of
the flower, which is accompanied with abundant excre-
tion of carbonic acid; it is further known, through
Saussure’s experiments, that the internal parts of the
flower, in the delicate tissue of which the formative
process deposits the smallest quantity of highly carbonised
substances, take up oxygen from the atmosphere and
excrete carbonic acid more abundantly than any other
parts of the plant ; again that the anthers are especially
distinguished among these, in which organs important
processes of solution of the tissue are connected with the
ulterior development of the pollen. In the nectaries
undecomposed sugar is excreted. There is no doubt but
all processes of solution and transformation in plants are
accompanied by excretion of carbonic acid. Observations
of the lower plants promises much more profit in this
respect. In Hydrodictyon I have seen cells in the stage
preparatory to the formation of gonidia (in which the
starch globules had already vanished), secrete gas bubbles
in unusual quantity ; I neglected to examine these
chemically, but they doubtless consisted of carbonic acid,
since they were visible very early in the morning and
later in the day when the sky was overcast, and since
other nets, in a vegetating stage, exhibited at the same
moments no such evolution of gas.

Ine examination of the processes of solution and des-
struction, which we see introduce the new structure at
deterrninate turning-points of vegetable life, and which
are all characterised by absorption of oxygen and ex-
cretion of carbonic acid, leads us to the comparison of
the nocturnal respiration of plants, in which, according

220

THE PHENOMENON OF

to the facts known about it, we can in like manner
perceive nothing eise tlian a periodical interruption of
the diurnal process of formation, by a process of deforma-
tion and de-carbonisation, although this does not so
profoundly affect the plant. It is true we cannot observe
in it any perceptible solution of cell-membrane, starch
granules, and the like, but there is no doubt of the
occurrence of an interruption in the deposition of these
structures, probably through the interposition of a process
of combustion of the raaterials out of which they
originate, while still dissolved in the cell-sap. It is
indeed not very adventurous to refer the lamellar depo-
sition of the cell-membrane, and the concentrically
laminated structure of the starch-grain, to this daily
periodicity of the cell-life. The great number of layers
wliich may be distinguished by suitable treatment in the
cell-membrane even of plants of short life ( Hydrodictyon ,
Cladophorci, Botrydium ), is not opposed to the assumption
that they are diurnal layers , and it is imaginable, under
this hypothesis, that bright and dull days, as well as the
age of the cell and other circumstances, may effect im-
portant modifications in reference to the formation of
distingnishable layers. Annual rings, or better, annual
layers, may doubtless be demonstrated in cells of perennial
dnration. T'he lamination described by Mohl,* in the
walls of liber-cells, for instance of Cocos and Calamus ,
which exhibit the peculiar phenomenon, that the thick
and not very numerous layers, which are separated from
eacli other by dilute sulphuric acid, are composed of an
outer, broadcr, and softer, and an inner, thinner and
firmer layer, may perhaps becompared witli the condition
of the annual rings of the wood of Dicotyledons, in
which, in correspondence with the reverse order of
formation, each yearly ring exhibits an inner, broader,
and looser, and an outer, narrower, and denser half. I

* ‘ Botanische Zeitung,’ 1844, p. 309, ^ (,tra|ls-

• Scientific Memoirs,’ vol. iv, p. 103, pl. i, ii, figs. 8, 25, 20.)

RKJUVENESCENCE IN NATUIIE.

OA [

found in the lowest internodes of the stein of the
perennial Chara ceratophylla , formed in the year pre-
vious to that in which it was examined, that the cell-
membrane, about Tg millim. in total diameter, was
composed of two very distinct portions of about equal
thickness ; while the thinner cell-membrane of the young
internodes of the stem exhibited no such sub-division.
In each of the two portions I could make out about 10
subordinate layers, which, however, were themselves of
compound nature. The agreement of the nocturnal pro-
cess of respiration of plants with the phenomena of
dissolution, through which we have seen the transition
to distinctly new formations prepared, is confirmed by
the epoch in which the latter usually make their appear-
ance. Observation of the Algse has furnished us with
most interesting facts in reference to this. Trentepohl* * * §
already observed that the expansion of the summits (the
preparation for the formation of the germ-cell) in Vaucheria
clavata took place especially in the night, and the exit
of the active germ-cell on the succeeding morning.
Ungerf confirmed this, for he characterises it as a re-
markable phenomenon that the unloosin g of the gonidia
of Vaucheria mostly occurs between eight and nine o’clock
in the morning. According to the Statements of ThuretJ
and Fresenius, § the same phenomenon is repeated in
other Algse. I have satisfied myself in all the green
Algse with active gonidia which I have had an oppor-
tunity of observing, that the preparation for the formation
of gonidia, and particularly the disappearance of the
starch-grains mostly connected with this, begins in the
night, and in general advances so far in one night, that
the formation of the gonidia can be completed and their
birth take place on the following morning. I will first

* According to Meyen, ‘ Pflanzenphys.,’ iii, p. 430.

f ‘ Die Pflanze im Momente der Tlnerwerdung/ p. 27.

% “ C’est surtout le matin qu’on trouve le plus grand nombre de spores
des Confcrves en mouvement,” Thuret, ‘ Sur les Organes Locomotcurs des
Spores des Algues,’ (‘ Ann. des Sc. nat.,’ 1843, p. 268.)

§ ‘ Zur Controverse über die Verwandlung der Infusorien in Algen,’ p. iv.

222

THE PHENOMENON OP

of all refer again to Ilydrodictyon as an example. The
reason why the mode of formation of the new nets in the
cells of the old one has hitherto been so rarely and so
inaccurately observed,* doubtless arises from the time at
which this process commences. If a single fully-developed
net of this plant, or even mere fragments of nets, are
placed in a shallow saucer of water, we may almost cer-
tainly reckon npon finding fully-formed young nets in some
of the old cells on the next, or at all events on the second
morning, and these in cells which exhibited no alteration
whatever.f If we wish to see the origin of these young
nets, we must not lose the earliest hours of the morning,
for the tremulous movement commencing after the forma-
tion is complete, and the final Union of the gonidia into
a net (see p. 137) takes place shortly after sun-rise, in
the middle of summer between four and live in the
morning, at the end of summer between six and eight
o’clock, and only in dull days of autumn, in which,
however, the formation of new nets rarely occurs, some-
times as late as ten o’clock in the morning. The
swarming out of the microgonidia of Ilydrodictyon
always takes place rather later in the day than the
formation of the nets, in summer usually between seven
and nine, in autumn between ten and two o’clock. As
the swarming lasts several hours, the active condition may
often be observed late in the afternoon (sometimes at five
o’clock in the evening)4

* The most recent treatise on this subject, by Morren (‘Mem. de l’Acad.
Roy. de Bruxelles,’) xiv, (1841,) is an almost incomprchensiblc tissue of errors.

f In deeper vessels of water the propagation does not commence so soon,
which is certainly explained by the diininished contaet with the atmosphere,
especially with the oxygen required for the process of solution.

+ In retard to the relation of the occurrence of the swarming-out
microgonidTa to the net-forming macrogonidia, I may add that it appears to
depend, in part, upon external circumstances. Many days I saw only net-
formation, in others both net-formation and swarming, on others, again, espe-
cially on dull and rough days, formation of swarmers in unusual quantity
unaccompanied by any net-formation. It is stränge that the formation of
swarmers, on the whole raore frequent than the formation of new nets, has
not been more frequently observed by earlier investigators. Treviranus saw
them but. did not observe their origin. (‘Beiträge zur Physiol.,’ p. 81.)

REJUVENESCENCE IN NATURE.

223

The gradual changes which take place in the water-
nets preparing for fructification, converting the contents
of the vegetative cell into thousands of gonidia, must be
observed by night; but it sometimes happens that, the
particular cells do not advance far enough in the dis-
solving preparation, in the course of the night, to enable
the influence of the morning’s light to complete the
formation. Such cells exhibit the earlier preparatory
stages, otherwise rapidly passed through in the course of
the night, with especial distinctness. Some thus remain
all day without any perceptible alteration, completing the
preparatory stages in the second night, and maturing the
gonidia on the second rnorning.

As a second instance, I will bring forward Ulothricc
zonata, a Conferva frequent in the mountain brooks of
the Schwarzwald, descending also into the plains in the
Dreisam. The mode of growth and the formation of
gonidia have already been examined (pp. 148, 159). If a
little tuft of this Alga is placed under the microscope in
the rnorning, filaments of two characters are seen ; some
(still vegetating) with parietal contents of the clearest,
brightest green, leaving the ends of the cells almost free,
in which green contents exist scarcely perceptible point-
like granules, a few small starch-globules, and a large
likewise parietal nucleus, which it is not easy to see ; the
others (in the condition of fructification) of somewhat
torulose aspect, and with more concentrated, darker
contents, divided into 4, 8, or 16 masses (gonidia). We
rarely find transitions from one structure to the other, —
namely filaments with darker and more opake green
contents not yet divided, in which the fine granules are
more strongly developed, but the starch-granules either
lost, or only their little nuclei visible, — because the
transitional stages are usually passed through in the
night, and the formation of gonidia completed early in
the rnorning. Birth and swarming of the gonidia, which
latter mostly lasts more than an hour, may be observed
all the rnorning. All the mature cells are usually emptied

224

THE THENOMENON OE

by the afternoon ; tliose not emptied by tliat time develope
no further. Once, however, I saw birtli of gonidia occur
between six and seven o’clock in the evening ; it was on
a very dull and rainy day in July, on wliich the weather
suddenly cleared up between five and six o’clock. I
have made similar experiments on many other fresh-
water Algae ; e.g., on Draparnaldio mutcibilis, in whichl
observed the birtli of the active gonidia in March from
eight in the morning, in May from six, and the svvarming
until eleven, a.m., at most. In Stigeodonium protensum (?)
the birtli and movement of the gonidia took place in May
between six and ten, a.m ; in Chcctophora tuberculata, in
August, between eight and two, a.m. ; in Ascidium acumi-
natum, in July, from six, a.m. to three, p.m., and even
still later, but none so late as dusk. The GEdogonia
also ordinarily cinit their large gonidia in the morning;
in summer and in bright weather earlier, in winter* and
in dull weather later. Since the swarming of the gonidia
lasts several hours, in tliis genus, it may be often observed
in the afternoon. In Chlamidococcus pluvialis, both the
birth of the first generation of gonidia, and the production
of the succeeding generations by division of the earlier,
occurs in the morning, after nocturnal preparation, and
the same is the case in the formation of new families in
the Volvocineac, for instance in Pandorina elegans. What
we have here seen in regard to the time of formation of
the gonidia of the Algaj, is true also of the vegetative
multiplication of their cells. Thus Fockef 1ms observed
tliat the division of the Euastra commences early in the
morning, and has advanced so far by evening, that the
complementary halves acquire their complete form and
full size before night. I have made the same observation
in regard to the first commencement of the division of
the cells in Spirogyra. For a long time I could not

* (Edogonium fonticola , wliich vegetates all through the winter in the
holes in running brooks, and developes the longest filaments at that season,
exhibits formation of gonidia even in winter when brouglit into the liouse.

t * Physiol. Studien.,’ (1847,) p. 47, t. ii, figs. 1,4, 5.

REJUVENESCENCE IN NATURE.

225

succeed in finding it, although I frequently met witli
cells recently divided. Not until I selected the earliest
hours of morning for the observation, and at last took
the precaution of placing specimens in spirit before sun-
rise, so as to be able to examine them at leisure later,
was I able to make out completely the process of division
of the cells in this genus. I shall describe it in the
next section of this treatise.

All these observations furnish the one common result,
that the processes of solution and deformation, the more
important as well as the slighter, occur at night, linder
the infiuence of determinate degrees of temperature,*
while, on the other hand, they confirm the experience
that the infiuence of light awakens the plastic processes,
formation of substances as well as production of form, in
the plant.f A number of well-known phenomena in
the great processes of Rejuvenescence of the Vegetable
kingdom have an intimate connection with these facts. It
is well known that vegetable life awakening from the
winter sleep requires, above all things, warm, dull, and
damp days, especially the warm showers of spring, to
enable it to dissolve the winter provision of nutriment,
on which the infiuence of light of the increasing days
may exercise its newly-shaping force; equally well-known
are the effects of the northern summer, which brings
many plants into flower and fruit more rapidly than our
temperate climate. It is the infiuence of light, increased
by the long days, which causes a more rapid development
of all products of form, an abbreviated course of the
metamorphosis, just as we see the plants on high moun-
tains also advance with more rapid steps to flower and
fruit, through less luxuriant development of the vegetative

* More exact observations are yet to be made on this point in the Algaj.
The rapid commencement of the formation of gonidia in Algae brought into
tlie bouse, doubtless depends on the slighter degrec of cooling occurring
during the night indoors.

t See the observations on Emstrum mentioned in the preceding page.
I shall describe more minutely, in the Appendix, the important changes of
form which the new-born cells of Pediastrum undergo in the coursc of t he
first day, and after a nocturnal rcst, agaiu on the second day.

15

226

THE PHENOMENON OE

preparatory steps, wlience we find many come into flower
sooner on the mountains than in the valleys or plains, as
is the case with the heather ( Ccdluna vulgaris), and
Parnassia palustris* In the eqnatorial regions, on the
contrary, where the seasons run into one another, forming
as it were an uninterrupted spring, where, day and night
being of the same length, the most intense action of
light (through the altitude of the sun and the trans-
parency of the atmosphere) is combined with the greatest
heat and moisture, where consequently the conditions for
both factors of the process of Rejuvenescence in Vege-
tation, dissolution and reconstruction, are united in high
and cqnal degree throughout the whole ycar, — there we
bchold the most luxuriant development of the Yegetable
kingdom in “ stock,” flower, and fruit, whose cpochs of
vcrdure, blossom, and ripcness, rnore separated in other
zones, are there most intimately interwoven.

III. — RECONSTRUCTION OF THE CELL.

The process of solution and destruction in the cells,
which wehave just examined, prepares fora renewed pro-
cess of construction ; the slighter and less perceptible the
process of solution, the more will the reconstruction appear
like amere continuating formation ; the more forcibly and
profoundly it takes place, the more distinctly will the
reconstruction appear as such, as is most of all the case
in the formation of cells of propagation. All formation
of new cells, therefore, is strictly a process of Reju-
venescence of the cell ; sometimes total, when the entire
contents are metamorphosed ; sometimes partial, when
only a portion of the contents pass over into new cell-
formation. If the transformation of the entire cell-con-

* Parnassia palustris flowers ou the higher mountain tracts of the Black
Forest, for instance on the Schauinsland and Feldberg, in spots more than
3000 fcet high, by the middle of June, while in the lowlands its floweriug
does not commcnce until the middle or end of July.

REJUVENESCENCE IN NATURE.

227

tents is combined with a division of thera, a raultipli-
cation of the celltakes place, constituting the basis of the
formation of tissues in plants where the cells remain
connected together, multiplication of the individual
where they separate. The various modes of origin of new
cells, which appeared so different and irreconcileable at
first sight, now all come together finally as cases merely
differing in degree of an essentially identical process, the
re-shaping of the cell-contents. The idea of origin of cells
outside, between or on the surface of existing cells,
formerly advocated by Mirbel, has proved untenable ;
neither the vegetative development nor the propagation
of plants exhibit anything but production of new cells
by transformation of pre-existing ones.* This has been
called propagation of cells, but it must be observed here,
that in the majority of cases the entire contents, i. e. the
whole active living organism of the cell, passes directly
into the new structure, so that nothing remains behind,
unchanged, of the old cell (the mother-cell), except the
passive membranous wall. The daughter-cells are there-
fore not to be considered as young produced by the
mother-cell, existing contemporaneously with it, nourished
by and gradually developed in it, but as the rejuvenised
and metamorphosed mother-cell itself.f This is most
strikingly evident in those cases where the entire and
undivided cell-contents become loosened from the mem-
brane of the mother-cell, and, shaping themselves in a
different way, become a new cell : as is the case, for
example, in the formation of gonidia and spores in
( Edogonmm , Bulbocluste, &c., and in the formation of the

* Furtlier rcsearches are required to decidc the relation of the in niany
respects enigmatical formation of the yeast-cells, (the first cells of the
fcrmentation fungus,) and other analogous cases of what is termed gencratio
sponlanea , to cell-formation in the normal course of development, and pro-
pagation of plants. (See Sclileiden, ‘ Grundz.,’ 2d Aull. 1, p. 203, ‘ Principlcs,’
pp. 36, 569, t. i, fig. 9, and Karsten, ‘ Urzengung, Botanische Zeitung,’
1848, p. 457.)

t I f cannot enter at length into the opposite vicw of Karsten, (‘De Cella
V itali,’ 1844,) but I may remark that so far as rclatcs to cell-formation it
totally contradicts my experience.

228

TUE PHENOMENON OE

pollen-cells in tlieir special mother-cells.* The whole
conception of the formation of new cells (daughter-cells)
in old ones (mother-cells), as it has grown up since first
brought forward by Schleiden, f now requires a further
elucidation, since it has been extended from the so-called
free cell -formation, to which alone it is perfectly applicable,
to the far more common cell-formation by division, whence
has arisen a nomenclature, to the equivocal character of
which I must liere direct attention. It is a raistake to apply
the word cell sometimes to the cell with a membrane, some-
times to the cell without a membrane, and sometimes to
tlic membrane without the cell. Since the contents of
the cell constitute the essential part of it (see p. 155),
since it forms, bcfore the secretion of the (cellulose-)
membrane (pp. 156 — 167), a separate entity, possessing
its own, essentially proper, membranous boundary (the
primordial utricle, pp. 169 — 173), we must call this
internal body the cell proper, unless we restrict the term
cell to the enclosing wall or chamber, and give the
internal body another name. If the name is restricted
to the internal body, we cannot, in the great majority of
cases, say tliat new cells are formed in the old, but
merely tliat tliey are formed out of the old, for even the
primordial utricle sliares in the division, in the propa-
gation of cells by division. Therefore when daughter-
cells are said to be formed in the mother-cells, or to slip
out from the mother-cells, or mother-cells are said to be
dissolved and absorbed, these phrases must be admitted
only as conveniently abbreviated expressions, “ mother-
cett” being liere used instead of maternal cell-membrane.
Finally, there are cases in which the expression, tliat
daughter-cells are formed in mother-cells, cannot be ap-
plied, even in this abusive sense ; these are the cases
above mentioned (p. 159) of division of cells which pos-

* According to Hofmeister (‘lieber die Entwicklung des Pollens,’ Bot.
Zeit., 1848, p. 431), the uucleus even survives this transition.

f “ The process of propagation of cells by the production of new cells in
tlieir interior, is the general law in the vegetable kingdom.” (Schleiden,

‘ Grundz.,’ 2 Aull, i, p. 305, ‘ Principles,’ p. 103.)

REJUVENESCENCE IN NATURE.

229

sess no cellulose layers at all, such as we have uudoubtedly
observed in the transitory generations of cells, through
which is effected the formation of the gonidia of many
Algae, ( Ulothrix , Chciracium, Pediastrum , Cystococcus,
Chlamidococcus, &c.)

Having made these preliminary observatious, I shall
endeavour to bring together, in a connected summary,
the various kinds of reconstruction of the cell, beginning
with the cases of entire metamorp'hosis of the contents.

a. Reconstruction without Division oe the cell.
— Here the character of the rejuvenised cell either remains
essentially the same, i. e., the repeated reconstruction ap-
pears merely as a development of the cell advancing by
periodical Rejuvenescence, as is the case more or less
evidently in the completing development of all vegetative
cells ; or the character of the rejuvenised cell becomes
different, the previously vegetative cell acquiring a
reproductive destination, at the same time being freed,
in its renewed structure, from the envelope previously
formed. In the latter case the rejuvenised cell will be
regarded as a new one, notwithstanding that, if we leave
out the inessential membrane which it throws off, it is
still the old, in reference to its essential part, the internal
body, as nmch as it is in the former case, only its shape
being changed. The intermediate stages to be enumerated
will show that these two cases are not so different as they
seem at first sight. We accordingly distinguish —

1. Reconstruction without division in vegetative cells,
prepared by the periodical nocturnal respiration ; ex-
pressed in the lamellar deposition of the cell-membrane

(p. 220).

a. The layers of cell-membrane are intimately adherent
together, and form a firmly-united, compound cell-
membrane, the layers of which are sometimes clearly
evident, but often only to be made out by artificial
loosening by rneans of Chemical reagents, e. g. Hydro-
dictyon, Cladopkora*

* Sec H. v. Mühl, ‘ Vermischte Schriften,’ t. xiii, f. 13, 14.

230

THE PHENOMENON OE

b. The outer layers of the cell-membrane become,
sooner or later, cracked and peeled off, which takes place
either by rapid growth of the cell, not inclusively of the
outer membrane, as in the paraphyses of Biphyscium
(p. 177), or through more or less abundant secretions of
jelly alternating with the lamellse of the cell-membrane,
as already mentioned in the description of the phenomena
of “ skinning” in Glceocapsci , Glceocystis , Pleurococcus
miniatus, Chroococcus decorticans (p. 182), Urococcus
(p. 178), and Schizochlamys (p. 181). The last-named
example,each new membrane being thrown off by a regulär
dehisccnce before the new one is formed, connects this
group of cases very clearly with the succeeding series.
The cell, as it were, new-born after every “ new skinning,”
is not regarded each time as a new cell, simply because
its character does not suffer any perceptible change. .

2. Reconstruction with out division in the transiiion
to fructification , or retroyressively from this to yermi-
nation. — In both cases the vital process of the cell
acquires with the reconstruction a new direction of the
physiological activity, an altered destination ; in the
former case, a transition from the vegetative growth to
the swarming condition of the gonidium, or the sleeping
condition of the spore ; in the latter, on the contrary,
from the sleeping condition to the vegetative develop-
ment. If in such a transition no throwing off of a
membrane formed in an earlier condition takes place, as
is usual in the passage of swarming gonidia into germi-
nation,* and occasionally happens in the transition of

* What becomes of tbe very rapidly vanishing cilia in this transition I
liave not been able to make out with certainty. Accordin" to Unger, they
are not thrown off in Vaucheria, but drawn in and smootnened down. In
AphanocJuste repens I once saw, on a gonidium passing into the state of rest,
in place of the large cilia, two extremely short processes, which exhibited a
jerking movement, (alternateiv stretclnng forward and retracting,) for a
short time longer. The gonidia of Characium Sieboldii exhibit, after they
liave already attached themselves by tlieir ciliated extremities, a tremulous
motion lasting for almost a quarter of an hour, and evidently commencing
in the delicate stalk. These phenomena certainly speak rather for a retrac-
tion tlian for a casting off of the cilia.

REJUVENESCENCE IN NATURE.

231

cells formed by vegetative growth into spore-sleep (see
Chlamidomonas, p. 215), the cell is regarded as one and
tlie same before and after tliis transition, in spite of the
difference of the condition ; but if the earlier envelope is
broken open or cast off in the transition to the new state,
the cell in its altered condition is regarded as a new one.
The loosening of the new cell frora the old cell-raembrane
takes place either by a contraction of the whole internal
body (including the primordial utricle), as, for instance,
in the formation of spores of most of the (Edogonia; or
it seems, vice versa, to be a swelling up of the contained
mass by occurrence of a secretion of cellnlose, which
separates the primordial utricle from the cell-membrane,
as in the gonidia of C Edogonium , Drapamaldia , &c. The
reason of the loosening of the contents of the special
mother-cell sliaping themselves into a pollen-cell, from the
wall of the former, is explained by Hofmeister* by the
specific nature of the substance secreted all over the
outer surface of the primordial utricle, which substance,
not adhering to the thickening layers of the walls of the
special mother-cells, forms the primary (subsequently the
inner) membrane of the pollen-cell. The following cases
may be cited, differing in the behaviour of the new cell
to the membranes of the mother-cell :

a. The new cell slips out of the membrane of the
parent-cell : as in the. active gonidium of Vaucheria,
(Edogonium, Bulbochate , Drapamaldia , Stigeoclonium,
Cluetophora, Coleocluste (see p. 183) ; the motionless
gonidium of Chantransia (p. 183) ; the spore of the
Fucoidese (p. 183).

b. The membrane of the parent-cell peels off the new
cell : as in germinating cell developing from the spore
of Mosses and Ferns, which tlirows off a mere incrusting
membrane; andof the Zygnemacese, which breaks through
a multiple spore-coat (p. 180).

* Hofmeister, ‘ Ucber die Entwicklung des Pollens,’ (‘ Bot. Zeitung,’
1848, p. 431.)

232

THE PHENOMENON OF

c. The new cell throvvs off the membrane of the
mother-cell by Splitting of the latter into uncoiling spiral
filaments : as in the spore of Equisetum (p. 180).

d. The new cell becomes free by the gradual solution
and resorption of the membrane of the mother-cell : as in
the pollen-cell of the Phanerogamia, the tetraspores of
the Floridese, and the spores, produced in fours, of the
Mosses, Liverworts, and Ferns, so far as they really
originate in special mother-cells. In thegerms Archidium ,
which produces the largest but fewest spores of any of
the Mosses, it appears from Schimper’s description that
the spores are forraed singly in the primary mother-cells,
and become free through resorption of the latter.*

b. Reconstruction with Division of tiie cell into
two daughter-cells. — Here we find repeated exactly the
same variations as we have seen in the reconstruction witli-
out division ; on the one side, retention of the previous
charactcr (at least in essentials), and ordinarily combined
therewith intimate connection of the newly-formed cells
with the remains of the mother-cell ; on the other side,
decided alteration of cliaracter, mostly connected with
emancipation from the membranes of the mother-cell.
The first case is again characteristic of the divisions con-
nected with the development of the vegetative tissues,
tlic latter of the transition to the formation of reproduc-
tive cells. Leaving out of view the division which occurs,
the analogy with the phenomena of reconstruction of the
cell without division is perfect. Tlius, for example, the
membranes of the daughter-cells originating by division, if
tliese retain the cliaracter of the mother-cells, bear exactly
the same relation to the membrane of the mother-cell, to
which they immediately adhere in their origin, as the
thickening layers of the mother-cell where no division
occurs, so that if it be correct in the one case to speak

* ‘ Recherches sur les Mousses,’ p. 77, t. 7, figs. 1—6. According to
Schimper, the capsule of Ärclddivm contains 18—20 spores Jth millim. in
diameter.

REJUVENESCENCE IN NATURE.

233

of the formation of two cells inside each mother-cell, it
will be equally correct in the other to call it a forma-
tion of one cell inside each raother-cell. In many cases,
indeed, it is altogether indifferent as regards the develop-
ment of the plant, whether such division takes place or
not. Compare, for example, H. von Mohl’s description
of some of the epidermal cells of Viscum cilbutn * which
is equally fitted to illustrate the inessentiality of individual
cell-divisions, and the agreement of the behaviour of the
membranous layers of new cells produced by division,
with that of simultaneous thickening layers of undivided
cells. In like manner it is often indifferent in the forma-
tion of reproductive cells, whether the contents of the
mother-cell are transformed into a spore or gonidium
undivided, or divided into two cells. Thus in Coleochcete
scutata, two gonidia are sometimes formed in one parent-
cell (by division of the contents) instead of one ; in
Aphanochcete repens (p. 184), on the contrary, it often
appeared to me that only one gonidium existed instead
of two (through omission of the dividing process) ; in
Stigeoclonium there occurs, in addition to the ordinary
formation of gonidia, a formation of microgonidia, in
which several gonidia are produced, instead of one , in a
mother-cell (see p. 139).

As to the great, even universal extent of the occur-
rence of division, and, in fact, halving of the cells, in the
development of the tissues of the vegetable organism, all
the most trustworthy of modern phytotomists, particu-
larly. Mohl, Nägeli, Unger, and Hofmeister, are agreed,
although they differ, in some respects, in their ways of
conceiving the dividing process ;f even Schleiden, who,

* ‘ Ueber die Cuticula von Viscum album ,’ (ßot. Zeit., 1849, p. 593,
t. ix, p. 59.)

f Note the following passages : “ These researches have led me to the
conclusion, that all vegetative cell-formation is a parietal cell-formation ”
(= eell-division). (Nägeli, ‘Zeitschrift,’ 1847, p. 49, Transl. in Ray
Society ’s publications, 1849, p. 121.) — “As regards, in the first place,
vegetative cell-formation, I believc i am justified by comprchensive researches
in the Algse, Fungi, Floridem, Mosscs and Chane, in the Vascular Crypto-

234

THE PHENOMENON OF

starting from the observation of cell-formation in the
embryo-sac of the Phanerogamia (the formation of endo-
sperm cells), formerly regarded free cell-formation as the
general law, (‘ Grundzüge,’ Ist ed., p. 195,) subsequently,
resting upon Nägeli’s researches, allowed cell-formation
by division a determinate although far too limited a
place, (f Grundzüge, 2d ed., p. 201 ; ‘ Principles,’ pp. 34,
568.) In the vegetative development of the Algae I
liave met with no other mode of cell-formation, so that I
must agree perfectly with Klitzing, when he says, “ the
origin of the tissue of Algae by division is universal.”
(c Phyc. Gen./ p. 60.) But more tlian this, the propa-
gative cells of very many Algae are formed by division,
of which I sliall hereafter mention examples. In the
Characeac, the development of which I have been working
out for several years, all the cells, not only of the vege-
tative tissue, but those of which the antheridium and the
jointed filaments contained in it are composed, and even
the spore, arc formed by cell-division.

The mode in which the process of division of cells
takes place has been represented in different ways. While
Unger* explains the division of the cell-contents by the
origin of a dissepiment (a partition), Nägeli,f eompre-
hending more correctly the relations of dependence
between the formation of membrane and the contents,
states, vice versa, that the formation of the septum
proceeds from the contents, previously divided into two

Samia, and in the Phanerogamia, in declaring it a general law, that here two
aughter-cells originate in a parent-cell, or in other words, that one cell
divides into two.” (Ibid., p. 66, Trans., p. 137.)—“ By formation of septa,
(cell-division,) therefore, the body of the plant grows; by formation of
septa the mass of the organic elements, the cells, &c., increases. Since
every plant is produced out of a simple cell, its growtli only division and
partial Separation (individualization) of the original one, it is not to bc
wondered at that, notwithstanding the multiplication of the One cell, a
Connection of its parts, intensive as well as extensive, contiuues to exist.”
(Unger, ‘Ueber Merismatische Zellbildung,’ 1814..) See also Hofmeister,
‘Die Enstehung des Embryo der Phanerog.,’ p. 1, (note,) and p. 61.

* ‘ Ueber Merismatische Zellbildung,’ 1844.

f ‘Zeitschrift,’ 1844, p. 73 et seq. (Itay Translation, 1845, p. 252);
1847, p. 51 et seq. (ibid., 1849, p. 123.)

REJUVENESCENCE IN NATURE.

235

halves; and Hofmeister,* in addition, directs attention
here more particularly to the primordial utricle, bounding
and cutting off the two parts from each other, even
before the origin of the celliilose dissepiment.

According to this representation, the septum is formed
by the two individualised portions of contents into which
the mother-cell divides, and which secrete cellulose lipon
their whole surface after they become separately consti-
tuted, touching by their flat adjacent surfaces; whence of
course the cellulose layers formed on the surfaces of
contact become united, and thus form what appears a
simple septum, which, however, from the nature of its
origin, is composed of two plates, standing in unbroken
Connection with the other parts of the new cellulose lining
which coats the sides of the cell turned towards the wall
of the mother-cell. Referring to the ab origine existing
contact of the daughter-cells with the whole internal
surface of the wall of the mother-cell, in formation of
cells by division of the whole contents, Nägeli calls the
formation of cells by division “Parietal cell- formation.”
Under the hypothesis tliat the contents become com-
pletely divided before the formation of the septum, he
regards the latter as simultaneous through its whole
extent. In contradiction to this last assertion, Mohlf
describes in Confervae, particularly in Conferva ( Clado -
phora) glomerata, a cell-formation taking place, by graclual
constriction of the cell-contents, in which the formation of
the new layers of cell-membrane begins, before the com-
pletion of the division, over the whole surface of the
primordial utricle, and, since it penetrates the fohl which
the primordial utricle forms at the place of constriction,
causes the formation of a septum penetrating gradually
from the circumference to the centre. In another place, |

* ‘ Die Entstehung des Embryo der Phanerogamen,’ p. 1 ; 1 Ucber der
Entwicklung des Pollens,’ (Bot. Zeit., 1848, p. G55.)

t ‘ Ueber die Vermehrung der Pflanzen-zellen durch Theilung,’ (Ver-
mischte Schriften, 1845, p. I3G2.)

+ ‘Einige Bemerkungen über der Bau der Vegetabilischen Zelle,’ (Bot.

236

THE PHENOMENON OE

where Molil describes the formation of the cells in young
points of stems and roots, and in the cambium layer of
Dicotyledons, he expresses a conjecture that the division
of the cells he observed in the Confervas is a totally
different process from the multiplication of cells in the
higher plants, since in cells dividing in this way no
nucleus can be found, while in the cell-formation of the
Phanerogamia these play an essential part. In the
multiplication of the cells of the Phanerogamia, moreover,
he never could observe a gradual constriction of the pri-
mordial utricle. In seeking to advance this difficult
point nearer to its solution, I remark, first of all, that
the essential part of the problem is not so rnuch the
question whether the cellulose septum is formed in
gradual progression towards the centre, or simultan eously
ovcr its entire surface, but the question, whether the cell-
contents are divided by gradual annular constriction
(with in-folding of the primordial utricle), or through
simultaneous Separation in the place of the entire sectional
plane, and the formation of two new coherent primordial
utricles. The succecding formation of the septum might
be simultaneous in its entire extent, even in the first
case, if, namely, the formation of membrane on the vvhole
surface of the primordial utricle, did not take place until
the division was coinplete; and, on the contrary, the
formation of the septum might advance in annular incre-
ments, in the second case, if the secretion of membrane
on the newly-fonned plate of the primordial utricle, did
not take place over the whole surface simultaneously, but
at the periphery earlier than in the centre. In the first
place, it is certain, notwithstanding Nägeli’s objections,
that the description given by Molil of the cell-division
taking place in Cladophora, by gradual constriction of
the contents, corresponds to the truth. I have seen this
process so completely and clearly in the large species of

Zeit., 1S44, pp. 289, 291,) (Trans!, in ‘Taylor’s Scientific Monoirs,’ vol. iv,

REJÜVENESCENCE IN NATURE. 237

Spirogyra , tliat not the smallest doubt could remain of
the actual existence of tlie division corapleted by gradual
advance frora the periphery to the centre.* The Obser-
vation in Spirogyra is the more important, since a nucleus
exists in this genas, wliich assumes an equally important
part in the division to that it bears in the division of the
young cells of the Phanerogamia. Conseqnently this
takes away the principal reason brought forward by
Mohl in favour of the total difference of these two modes
of cell-formation, so that one might seek to explain the
distinction of the ordinary process of cell-formation,
characterised by the previous formation of new nuclei
and the sudden appearance of a line of fissure between
them, from the division by gradual constriction, by the
greater or less rapidity of an essentially identical process,
and to regard the first even as a gradually completed
division, only running through its course so rapidly that
the transitional stages are concealed from observation.
On the other side, it is true, an objection to such an
assumption may be found in the analogy of the process
of cell-division , such as occurs in young tissues, with free
cell-formation. In both the new cell-formation is intro-
duced in the same way by the formation of the nucleus,
and if, in free cell-formation, a mass of contents situated
around the shortly previously formed nucleus, becomes
bounded and cut off simultan eously over the whole peri-
phery (so far at least as observation reaches), analogy
would lead us to suppose that in cell-formation where
the entire contents of the cell part into two masses,
surrounding the newly-formed nuclei, each of these
masses of contents will bring as mach of its periphery
as is not otherwise previously determined, — therefore its
surface of contact with its fellow, — simultaneously to
definition and completion in its whole extent. The
sharpness of the distinction in the idea of ordinary cell-
division, according as we try to bring it into agreement

* See the subsequent description.

238

THE PHENOMENON OF

with the constrictive division of tlie Conferva-cells, or with
free cell-formation, becomes softened to some extent, if
we reflect that the process wliich we have termed con-
striction is by no means a mere mechanical process of
folding-in, but rather a process of definition advancing in
the form of an annularly penetrating incision, thatinthis
case also the external division is preceded by the internal,
first expressed in the formation of two new nuclei, as
may be demonstrated at least in Spirogyra. Conseqnently
the question is, essential ly, in which cases does the
cell-formation complete the development of the bonn da-
ries on all sides and in all parts simultaneously, and in
which does it advance gradually and according to definite
laws. On this point, I am convinced, natnre will be
found to exhibit a far greater multiformity than has
hitherto been snspected. As the cell in its subsequent
development displays sometimes an all-sided growth,
sometimes a one-sided, sometimes a two-sided, or a
growth regularly distributed in varying intensity in a
still more complicated way, there certainly exists a variety
of cases of regulated progress in the very first develop-
ment of the boundaries of the cell. Thus, in the lower
plants, there undoubtedly exists a division advancing
from one end of the cell to the other. In Chlamidococcus
pluvialis, in which the division of the cell in the later
active gencrations often begins even before the cessation
of the movement (see p. 208), I have very frequently
seen the division advance very gradually from the pos-
terior to the anterior, still ciliated extremity. A one-
sided advance of the division from the upper end of the
cell to the lower (which corresponds to the ciliated ex-
tremity of swarming gonidia) may be conjectured of
the Diatomaceae with fan-shapcd cells and dichotomous
peduncles ( Gomphonema ), as also of the Palmellaceae
with delicate peduncles issuing from the internal cell-mass.
(Dictyospharium, Näg.) As regards the ordinary cell-
division, apparently taking place simultaneously over the
whole surface, it is a question whether or not the pri-

RF.JUVENESCENCE IN NATURE.

239

mordial utricle of the mother-cell (analogous to the
micleus of it) is here totally dissolved and reconstructed.
Tor the former view, for a total solution and reformation
of the primordial utricle, it seems to me that no sufficient
reasons can be found, at all events in ordinary vegetative
cell-formation ; but if a total solution of the primordial
utricle does not take place, but merely an interruption of
its continuity in the periphery of the place of di vision,
the hypothesis of a completion of the primordial utricle
for each of the daughter-cells, through a formative move-
ment issuing and advancing from the parts already
formed, which is demonstrated by observation in Clado-
pliora and Spirogyra , appears to me not improbable, even
for the seeming simultaneous division. The principal
distinction between these two cases depends evidently on
the age of the cell at which the division takes place.
There are cells which never become old, but in their
earliest age, by dividing, give up their existence again, or
rather continue it in a new generation, tili age is finally
attained in a last generation, which never undergoes
division. This is the condition in the cells of the young
tissues of the higher plants, which often divide again
when scarcely formed, still small, and thin-walled, with
comparatively large nuclei, and abundant viscid Con-
tents. To such cells, which have not yet lost the
character of youth, belongs the apparently simultaneous
cell-di vision. Hofmeister* expressly remarks that this
kind of cell-formation takes place everywhere that the
volume of the mother-cell does not very considerably
exceed (at least about sixteen times) the circumference of
the nuclei of the new daughter-cells to be formed. On
the other side, there are cells (probably only in the lowest
stages of the Yegetable kingdom) which may be said
never to be young, since they display from their earliest
origin the characters of old cells ; for instance, a nucleus
(perhaps sometimes altogether deficient) very small in

* ‘Die Entstehung des Embr. der Phanerog.,’ p. I.

240

THE PHENOMENON OE

Proportion to their frequently very considerable size,
a large internal cavity filled witli watery fluid, parietal
distribution of tbe consistent portion of the contents,
fully-developed starcb-grains, &c. To such old-born cells
belongs the gradually advancing nmltiplying division, as
has been described by Mohl.

1. Reconstruction witli division into tivo daugliter-
cells, in the dornain of vegetative cell-formation.

a. Ilalving through evidently gradual constriction ;
Old-cell-division. — The primordial ntricles of the daughter-
cells are cut off by a process of formation advancing
gradually from the periphery to the centre ; the formation
of the cell-membrane commences before the conclusion of
this cutting off, the septum is consequently formed in the
shape of an annular ridge (or propcrly a double-plate)
gradually increasing in breadth, finally closing -in in the
centre.

a. Without ci nucleus? Here rcfers the cell-division
of Cladophorce, in which at least no nucleus has yet been
found. It has been described in detail by IT. von Mold,*
in Cladophora gl om er ata, as above mentioned.

ß. With a nucleus. — My observations on this point,
to be brought forward here, vvere made on Spirogyra
nitida and jugalis , which are probably botli forms of one
and the same species, the former ^ the latter about
^ millim. in diameter. The position and character of
the nucleus of Spirogyra are well known ; it appears
particularly sharply and distinctly when spirit is applied,
which however generally disturbs its originally central

* ‘Vermischte Schriften,’ p. 362, t. xiii. With regard to the many-
layered membrane marked b in fig. 5, and c in fig. 14, I venture to remark
tliat the same is wrongly described at page 365, as a connected tubulär
envelope of all the cells, as it were a colossal branched cell. Only the
gelatinous, slimy investment marked a, (fig. 5,1 and d, (fig. 14,) forms such
an universal envelope; the many-layered membrane, on the contrary, forms
a very complicated System of encasement, since its innermost layer encloses
only two cells, its inmost one but three cells, aud so on outward a pro-
gressively larger number of cells. In the further description, indeed,
especially at pp. 368-69, the assertion made at first is partially corrected
by Mohl himseif.

REJUVENESCENCE IN NATURE.

241

Position, and draws it to the side, througli the contraction
and partial tearing up of the radiating mucilaginous
threads fixing it in tbe cavityof the cell. Before the applica-
tion of iodine it has a homogeneous aspect, and the line
of demarcation between its body and the surrounding
mucilaginous envelope running out into radiating fila-
ments, is difficult to see ; on the application of spirit the
outline becomes clear, and the inferior acquires a granular-
punctate aspect; the large nucleolus always existing also
appears punctated in the inferior. The nucleus is some-
what lenticularly compressed in relation to the longi-
tudinal axis of the cell, its larger diameter amounting, in
Spirogyra nitida , on an average, to about ^d, that of the
nucleolus -^tli millira. The size of both increases some-
what during the ulterior development, and most con-
siderably just before the commencement of the division
of the cell, at which time its lenticularly-abbreviated
shape is also somewhat elongated. I have not been ablc
to make out clearly whether there is a division of the
nucleus liere, or a solution of it followed by the formation
of two new nuclei, or how the nucleoli behave in this
doubling. When the cell is near to division, two new
nuclei present themselves in place of the original, con-
siderably smaller than it, and with proportionate nucleoli.
The two new nuclei touch at first, but I never saw thein
lying flat upon one another, as if produced by division ;
they always had rounded surfaces. The circumstance that
the two new nuclei are surrounded by a common, abundant
mucilaginous envelope, not existing previously, seems to
me to speak rather for a solution of the original nucleus,
than for a division of it. Simultaneously with the appear-
ance of the two new nuclei, we discover an extremely
delicate line upon the surface of the cell-contents, indi-
cating the division now beginning also at the periphery ;
this line is, however, so delicate at first, that when we
have the margin of the cell in focus, no trace whatever
of a grooving or constriction of the primordial utricle can
be detected, and the spiral Chlorophyll bands, threc of

16

242

THE PHENOMENON OF

which ordinarily exist in Sp. nitida , at this periocl retain
their course wholly uninterrupted. The two nuclei now
gradually separate from one another, the mass of mucilage
still enveloping and connecting them becoming at the
satne time drawn out lengthways, and finally lost in
longitudinal mucilaginous cords running between them ;
an accumulation of granulär mucilage often remains mid-
way between the two. Contemporaneously with the
Separation of the new nuclei progresses the division com-
mencing at the periphery, and by no means as a coarse
constriction or folding, but in the form of an extremely
delicate incision, continually advancing deeper into the
cavity of the cell, with the sharp edges of the surfaces of
section reaching close up to the membrane of the mother-
cell, without being rounded off or separatcd by an
annular intercellular passage. In cases where the dis-
tance of the two nuclei equalled once or twice their
shorter diameter, the Separation penetrating from the
periphery extended scarcely to a sixth part of the diameter
of the cell ; where the nuclei were removed to a distance
of about four tiines their diameter, I found the division
advanced to §ths, so that the part still open of the Con-
nection between the two daughter-cells, was limited to
±th the original diameter. The process of this gradually
incising partition of the daughter-cells can hardly be
otherwise explained, than through a gradually progress-
ing formation of two plates of the primordial utricle,
gradually shutting off the daughter-cells, these plates
starting from the line of limitation which has made its
appearance in the primordial utricle of the mother-cell,
and advancing towards the centre of the faces of contact
of the two daughter-cells. If we cause contraction of the
primordial utricle, and loosen it from the cell-membrane,
by the application of acids, in these cells also, which are
not yet completed, the walls of the incision retreat from
eacli other, to that the mass of contents encloscd by the
primordial utricle in such cells, appears constricted in
the middle by a widcly opened groove, morc or less deep

REJUVENESCENCE IN NATURE.

243

according to the degree of division. By tliis means also
we may satisfy ourselves that the secretion of cellulose
in the notch of the primordial utricle begins before the
termination of division, consequently that the septum is
originally an annular ridge, not reaching to the middle.
I could already distinguish its rudiment in cases in which
the notch occupied about £th of the diameter. Extremely
thin and delicate as the septum is in its earliest rudi-
ments, it separates completely from the walls of the
retreating notch of the primordial utricle, and appears
as a ridge attached at right angles on the cell-wall,
without an intercellular passage, diminishing to inappre-
ciable thickness at the bottom of the notch. That the
contents of the two daughter-cells are not merely appa-
rently (by adherence of the two portions to a septum
thinner in the middle), but really directly connected, in
these stages of transition, follows, not only from the
already described connection of the two nuclei by the
mucilaginous mass drawn out into a filament, but also
from the behaviour of the spiral Chlorophyll bands. As
soon as the peripherical groove has attained a distinguish-
able depth, an interruption of the regulär course of these
bands takes place ; they become pushed forcibly into the
interior of the cell at the point of transition, becoming, at
the same time, loosened from the primordial utricle for
some distance from the notch. The more they are bent
into the centre of the cell, the more they are attenuated
at the point of transition, tili at length the connection is
dissolved. I could trace their uninterrupted course from one
cell to the other clistinctly, even in cases where the diameter
of the isthmus did not amount to more than |th of the
diameter of the cell. After the division is completed,
the position of the nucleus remains excentrical for some
time longer, nearest to the newly formed wall ; but it
soon retreats to the middle of the cell, the mucilaginous
filaments radiating from it, which were at first directed
in greatest number and thickness to the newly formed
septum, finally ran principally to the lateral walls of the

244

THE PHENOMENON OP

cell. The iraperceptible increase of lengtli during the
rapid course of this process, is a proof that the alteration
of position of the nucleus is a real change of place, and
not effected by a one-sided complementary growth of the
cell (like that in the Desmidiaceae). Hence we ordinarily
find the nucleus again in its characteristic central position,
as in the older, larger cells, even in newly-formed cells
scarcely more than half the lengtli of the mother-cells.
When the cells have attaincd the normal dimensions, by
doubling tlieir lengtli, the process of division is repeated,
tili at lengtli fructification commences. Excepting the
processes relating to the nucleus, no perceptible pheno-
niena of solution occur as preparatory to the division of
the cells ; in particular, no change is detected in the
green bands or the starch-grains existing in them. I
have a little more to add in regard to the cell-membrane,
especially the relation of its different layers to the series of
generations of cells. In the larger Spirogyrce a double
membrane may be clearly detected : an outer, which
cnvelopcs all the cells of the filament in common, which
I will call thecuticle ( Ueberhaut , cuticula ) ; and an inner,
the true cell-membrane, which, when superficially ex-
amined, seems to bclong to the individual cells, but, in
reality, reprcsents a very complicated System of encase-
ments. Between the outer and inner coat, we may
sometimes distinguish by its darker colour a membranous
layer, which however is neither a simple nor a special
membrane, but belongs to the System of layers of the
internal membrane. The cuticle is very thin in 8p. nitida
and jugalis, at most ^ millim. thick, more transparent
than the proper cell-coat, from which it is distinguished
also by its behaviour witli acids and solution of potash,
as it does not swell up. On the surface it exhibits very
numerous, irregularly scattered, sharply circumscribed,
circular bright points, scarcely ^th millim. in diameter,
which in the sectional view of the cuticle appear as
streaks running crossways through it. These streaks
are still more distinctly seen in 8p. lubrica, in which the

ItEJUVENESCENCE IN NATURE.

245

cuticle (i^j) is far thicker than the cell-membrane. When
tincture of iodine is applied, the said streaks acquire a
brown colour, wkile the mass of the cuticle remains
uncoloured, which, as well as the general aspect, makes
tlieni look like little canals perforating perpendicularly
through the cuticle. We have no observations on the
mode of origin of this cuticle, but I should rather incline
to regard it as an incrustation- membrane, than as the
primary cell-membrane of the first cell of the filament.
The more complicated structure of the proper cell-mem-
brane only becomes evident after long action of solution
of potass, when the membrane, about —th millim. thick,
swells up to almost three times the thickness, and dis-
plays clearly at least the principal constituents of which
it is composed. It consists, as examined from within
outward, of a series of layers, the inmost of which clothes
one cell only, the second two, the third four, the fourth
eight cells, &c. The first and second layers, from within,
are most clearly distinguishable, and one or other of them
is the thickest of all, according to the age of the cells ;
the further outwards, the thinner and less distinguish-
able become the lamellae, so that usually only four of
these can be distinguished, the outermost of which, how-
ever, (of course only in old filaments composed of
numerous cells,) we must regard as composed of several.
These various layers are the membranes of so many
different cells encased one within another. The inmost
layer alone constitutes the special cell-membrane of the
individual actually vegetating-cell ; at the time of the
full development of the cell, it is thickest of all. The
second layer is the membrane of the immediately pre-
ceding mother-cell, it therefore encloses two cells, and
becomes attenuated by the extension which it must
necessarily undergo during the period of growtli of the
daughter-cells, so that it is only about half as thick as
the lully-developed membrane of the daughter-cell. The
third layer is the cell-membrane of the penultimate
mother-cell (the grandniothcr-cell) ; it encloses four cells,

246

THE PHENOMENON OF

ancl is about half as tliick as tlie second, &c. By tkc
increased expansion and corresponding attenuation, which
the cell-membranes of the mother-cells lying further back
in the series of generations undergo, it is conceivable
that they must become constantly less clearly distinguish-
able as separate layers, and finally vanish entirely. Each
such layer, or rather special cell-membrane, is itself again
composed of numerous extremely delicate lamellar, formed
successively during the life-time of the individual cell,
which, however, can only be detected in the inner thicker
layers, and there very indistinctly. The character of the
septa is inost intimately connected witli this System of
encasing of the cell-membranes. Between two sister-cells
the septum is composed of the mere continuation of the
innermost cell-membrane (that belonging to the individual
cell), clearly passing over into this, and increasing in
tkickness in ecpial proportion during the growtli of the
cell. The structure, as composed of two lamellse, may
be detected even in the very thin septa of young sister-
cells, in the swollen-up condition. No intercellular
passage exists at first in the periphery of the septum, but
it is gradually formed during the increase of thickness of
the septum, and is situated between the membrane of the
mothcr-ccll and the two daughter-cell membranes forming
the septum. The septum between two pairs ofdaughter-
cclls (between the first-cousin-cclls), is formed of the
membranes of tlie daughter-cells and tliose of the mother-
cells, thus of four laminse ; the intercellular passage
existing at its periphery is situated between membrane
oftkegrandmother-celland membrane of the two adjacent
mother-cells. The septum between two double pairs of
of first- cousin-cells (between second-cousin-cells), is
formed of the membranes of the daughter-cells, mother-
cells, and grandmother-cells, thus of six layers; the
intercellular passage lies between the adjacent grand-
mother-cell membranes and the membrane of the great-
grandmother-cells, which, however, (together with all the
membranes lying outside it,) is so thin, that it appears as

REJUVENESCENCE IN NATURE.

247

if in contact with the cuticle. All this may be very
exactly traced out in the larger species of Spirogyra ; and
I add, in conclusion, tliat all the subdivisions of the cell-
membrane (exclusive of the cuticle) svvell up rnost
strongly in the vicinity of the intercellular passages.

A similar gradual progression of the cell-clivision will
doubtless be found in other Confervse not yet accurately
examined in this respect. Observation of the process of
division in (Edogonium and TJlothrix, which genera have
a lateral nuoleus, would be very interesting. The rela-
tionship which exists between the Desmicliaceae and the
Zygnemaceso, as also the occurrence of a central nucleus
observed in many of the genera of that family, leads to
the conjecture that their division corresponds to the pro-
cess in Spirogyra. In the Diatomacese the presence of a
nucleus is still doubtful ; the age at which the division
takes place, however, leads us to expect a gradual pro-
gress of the division. Most genera of the two families
last named, present us, at the same time, with examples
of complete Separation of the two cells formecl by division,
the membrane of the parent-cell either gradually vanishing
or being peeled off. (See pp. 180, 181.)

b. Iialving with ( apparently ?) simultaneous definition
of the entire surface of division. Young-cell- division. —

This is the ordinary mode of formation of the cells in
young developing Organs of the Phanerogamia,* * * § Yascu-
lar Cryptogamia, Mosses,f Characese, Ploridese,^ and
Pucoideae.^ The formation of the special mother-cells of
the pollen of the Phanerogamia, || and of the spores of
the Cryptogamia, when this takes place through repeated
halving, also belongs here ; in like manner the formation

* Scc, for instance, the course of development of the ovule of Orchis, in
Hofmeister, ‘Hie Enstchung des Embryo der Phanerogamia/ pp. 1 — 3, t. i.

f Näjjeli, ‘ Zeitschrift/ 1845, p. 138, t. ii, iii.

% Ibid., 1845, p. 119, t. i, (‘ Growth. of Uelcsscria Jlj/pof/lossum’) and 1847,
p. 207, t. vi, vii ( Polysiphonia .)

§ Ibid., 1844, p. 73 et seq.

|| Nägeli, ‘Entwicklungsgeschichte des Pollens/ 1842; Hofmeister, ‘Uebcr
die Entwicklung des Pollens/ (‘ Eot. Zeitung/ 1848, pp. 425, 649.)

248

THE PHENOMENON OF

of the cells of the embryo of the Phanerogamia, and in
many cases even tlie formation of the endosperm-cells.* * * §
Numerous researches on this kind of cell-formation agree
essentially in the following points : the nucleus of the
mother-cell is more or less completely dissolved ; in its
place are prodnced two new nuclei, either near together,
or at a distance. Between these snddenly appears a line
of division (really a plane of division) which indicates a
parting of the cell-contents into two portions, each of
which encloses one of the nuclei. The two portions of
contents are originally bounded only by their primordial
utricles, which immediately secrete a new cell-membrane
ovcr the whole of their surface, and thus form a septum
between them at the surface of contact. Many observa-
tions testify that the two daughter-cells are completely
scparated, by the shutting off of their primordial utricles,
before the origin of the septum. Thus Moldf frequently
observed two primordial utricles in one cell, in cambium,
as well as in the tips of stems and young leaves of various
plants ; Hofmeister J represents such a case in the embryo
of Leucojum cestivum, and also, in the description of the
formation of the special mother-cells of the pollcn of
Passiflora, and Pinus,^ endeavours to show the formation
of the septum to be subsequent to the division of the pri-
mordial utricle. With regard to the behaviour of the nucleus,
it must be remarked, that according to the observations of
Mold and Nägeli, the formation of the two new nuclei takes
place in many cases through division of the nucleus of
the mother-cell || (without solution of this). It seems to

* Hofmeister, ‘Die Enstehung des Embryo der Phancrogamcn,’ 1849,
e. ff., p. 35, t. xii. {Monotropa) ; p. 40, t. iii. (Bartonia.)

’f ‘Bot. Zeitung.,’ 1844, p. 290, (Trans, in ‘Sc. Mcmoirs,’ vol. iv,
p. 96. — A. H.)

1 ‘ Die Enstehung des Embryo,’ t. vi, f. 20.

§ ‘ Ueber Pollen,’ ‘ Bot. Zeitung.,’ 1848, pp. 654, 671.

|| Yide Nägeli, ‘Zeitschrift,’ 1844, p. 75. (Trans, in Ray Sociely’s
publications, 1845, p. 254,) wbcre is described, of Sp/iacelaria, a division of
the central nucleus of the mother-cell prcceding t he division of the cell,
while in Zouaria Pavonia , and Cystoseira, the parent nucleus is said to

REJUVENESCENCE IN NATUllE.

249

me very doubtful whether tvvo different conditions of tliis
case really occur, since a rapid reconstruction of the
nuclei of the daugbter-cells out of the still accumulated
mass of the nucleus of the mother-cell, in a state of
solution at its periphery, may readily be looked upon as
a division of the latter.

How far either the partition of the primordial utricle,
or the formation of the dissepiment between them, is
really, or only apparently, simultaneous over the whole
face, can scarcely be decided in the present stage of
observation. Very few observations speak in favour of
the latter assumption. In one case, certainly referring
liere, namely, to the “ young-cell- division,” in the forma-
tion of the stomate-cells (see the preceding note), Mohl
asserts that he observed the formation of a septimi
beginning with the produetion of an annular ridge. I
should consider as an indication that the division of the
primordial utricle also begins at the periphery, the
formation of the at first simple zone of granules, subse-
quently doubled by a clear line of division, at the equator
of mother-cells of the pollen of Pinus * preparing for
division, and already provided with two nuclei, — a phe-
nomenon which seems to indicate a conflict of the two
newly-formed centres, expressing itself first of all at the
periphery of the plane of division, when they are defining
their boundaries. I shall hereafter mention a structure

vanish, and be replaced by two new ones. Nägeli furtber describes the
division of tbe nucleus in the cells of the hairs of tue stamens of Tradescantia
(1. c., p. 67 ; Ibid., 1847, p. 102 — Translation in Ray, vols., 1845, p. 246,
1849, p. 168,) wbile according to Hofmeister, (‘Enst. des Embryo/ p. 8,
t. xiv, figs. 20, 28) tbe membrane of tbe parent nucleus is absorbed, so that
only the mucilaginous and no longer sharply defiued body of its contents, is
divided into two globular balls, which become tbe new nuclei. According
to Mobl, (‘Vermischte Schriften/ p. 252,) tbe nucleus of tbe mother-cell
becomes divided, in tbe formation of stomates, to form the nuclei for tbe
two boundary cells of the stomatal opcning. According to Nägeli, (‘Linna;a,
1842, p. 287,) on tbe other band, the formation of tbe two new nuclei is
preceded by a disappearance of the nucleus of tbe mother-cclJ.

* Hofmeister, ‘13ot. Zeit./ 1848, p. 671, t. vi, f. 22, 24. In Passiflora,
on the contrary, tbe zone of granulös is replaced by a granulär plate occupy-
ing tbe whole surface of division. See t. vi, f. 8, 9.

250

THE PIIENOMENON OF

analogous to this zone of granules in the description of
the formation of the gonidia of Hydrodictyon.

2. Reconstruction , with division into two dauyliter-
cells, in the domain of fructißcation.

a. The newly-formed cells are neither connected
together, nor with the membrane of the mother-cell.
The cells produced by division either divide anew (as
a transitory generation), without having acquired a
cell-membrane, or, if no fresh division occurs, they
are set free, naked and furnished with cilia, by tear-
ing of the mother-cell. Iiere belong the gonidia of
many Algse, of which mention has been already fre-
quently made. Either two gonidia are formed in one
mother-cell (by simple division of the contents), as in
Ulothrix Braunii (see pp. 177, 183), Aphanochcete
repens (p. 184); or four, cight, sixtecn, or thirty-two
gonidia, according as the division is repeated once or
more timcs, as in Ulva, Enteromorpha , Ulothrix zonata
(p. 184), Characium (p. 185), Chlamidococcus (pp. 184,
20G, &c.), &c.

h. The newly-formed cells, free (active) at their birth,
become united into a regularly arranged colony after
birth. This occurs in Pediastrum (p. 184).

c. The newly-formed cells become combined into
families before birth, either united by formation of firm
membranes, as in Scenedesmus (Nägeli, ‘Einz. Algen/
t. v. a), or held together by a development of gelatinous
matter, as is the case in the Volvocineas.

b*. Reconstruction, witii division, into two cells,

ONE OF WHICH REMAINS AS THE MOTHER-CELL, THE OTHER
BE1NG SI1UT OFF (ABGEGLIEDERT) AS A DAUGIITER-CELL.

In the cases comprehended under b, the two cells formed
by the division of the mother-cell are either alike in every
particular, or, if they differ, take an equal share in
the process of Rejuvenescence through which they are
formed, appear both equally active agents in the re-
construction, and therefore are regarded as equal
daughter-cells of one mother-cell (destroycd by the

IlEJÜVENESCENCE IN NATURE.

251

division). But tliere are other cases in which the- re-
juvenising activity appears solely, or at least principally,
in a definite part of the mother-cell, which becomes
finally cut off, as a newly-formed daughter-cell, by
division of the contents and formation of membrane,
from the other relatively inactive portion, retaining un-
changed the properties of the mother-cell.

The distinction of a shutting off of this kind from
ordinary division, is especially evident whenever the
behaviour of the nucleus can be observed, as is the case
in certain examples described by Hofmeister, which I
shall mention hereafter. In such cases, namely, instead
of the formation of two new nuclei, a single new nucleus
presents itself in some portion of the mother-cell (offen a
Prolongation or bag-like protrusion), upon which the
part of the mother-cell containing the nucleus separates
as a distinct cell. The original nucleus remains durin g
this process in unaltered existence, or, if it has vanished
before the formation of the daughter-cell, no new nucleus
is formed in the part remaining as mother-cell during
the cutting-off of the new cell. Nägeli* and Hofmeisterf
have applied to this modification of cell- division the term
“tying-off” (Abschnürung), a name, however, only
properly applicable to those cases where the daughter-cell
becomes externally detached from the mother-cell. Mul-
tiplication of cells by the formation of shut-off brauch
sprouts likewise belongs here.

1. The shutting -off (. Abgliederung ) of a daughter-cell ,
in the domain of vegetative cell-formation.

a. The apex of tlie cell is shut-off as separate cell .

a. W ithout nucleus? Here refers the formation of
the mother-cell of the active gonidium, as also of the
motionless spore of Vaucheria, under the hypothcsis,
tliat in both these cells a proper membrane is formed
(sharing the formation of the septum), before their

* ‘ Zeitschrift, ’ 1847, p. GO, (Ray Traust, 1849, p. 131,) ‘ Einzell. Algcu,5

p. 18.

f ‘Eiist. des Embryo der Phaucrog.,’ p. 61.

252

TIIE PHENOMENON OF

contents are metamorpliosed into a fructification-cell ;
therefore that they have a vegetative existence, short
thougli it be, previously to the fructification. In the later
behaviour, the difference presents itself, that the gonidium
leaves its mother-cell by slipping out, while the spore
appears to tear away the membrane of the mother-cell
with it. The formation of the fruit-club of Saprolegnia
also belongs here. The process of shutting off the apex
may be repeated many times, in a retrogressive Order,
in the same cell, as occurs not unfrequently in Saprolegnia ,
where a second, and often a third piece of the cell is
dcvcloped, imderneath the first fruit-club, into a gonidium-
case or spore-case (both are met with). Or the shut-
ting off is repeated in an apex reproduced by a growing
through of the empticd fruit-sac, as likewise occurs in
Saprolegnia (particularly S. fcrax, S. prolifera ) and in
Vaucheria clavala*

ß. With a nucleus. A remarkable example of this
* is furnished by the origin of the sacculate appendage of
the enibryo-sac of Bartonia , described by Hofmeister. f

The upper end of the embryo-sac (the mother-cell of
the germinal vesicles and cndosperm-cclls), after three
free germinal vesicles have been formed in it, produces a
Prolongation pcnetrating into the canal of the micropyle,
wliich, after tlie previous formation of a nucleus, becomes
shut off from the embryo-sac as a separate cell. In general
the primary nucleus of the embryo-sac is not dissolved
during this process. The first division of the germ-cell (the
germinal vesicle) of the same plant J affords another
example. The originally roundish, nucleated germinal
vesicle becomes elongated in the form of a tubulär cell,
the nucleus at the same time vanishing. In the front
part of the cell, turned away from the micropyle, a some-
what flattened nucleus is now formed, and in consequence
of this a Separation of this anterior extremity as a dis-

* Yide TJnger, 1. c., flg- 13.

f ‘ Enstehung des Embr. der Phanerog.,’ p. 39, t. ii, f. 31—10.
| Hofmeister, 1. c., p. 10, t. iii, f- 1 H*

REJUVENESCENCE IN NATURE.

253

tinct cell, while no new nucleus is formecl in tlie longer,
posterior part of tlie cell. According to Hofmeister,*
the second cell of the proembryo (the cellular filament
first developed from tlie germinal vesicle, the suspensor)
is formed in a manner essentially the same, in Monotropa, t
Gagea,\ Fritillaria , Martynia , and Linum.

b. A lateral growtk from the cell (a cell-branch )
becomes shut-off as a separate cell. This process also
may be repeated in the same mother-cell when several
branches arise from it one after another, as occurs in
Cladophora glomerata. The branches arise sometimes
from the upper margin, sometimes from the lower, and
sometimes from the middle of the cell ; sometimes from
the upper and lower border at the same time, as men-
tioned already of Chcetophora and Coleochcete pulvinata
(p. 150). According as the ramification commences in
the earliest youth of the cell, or at a later epoch, in
somewliat advanced development of the cells, the shutting-
off of the branch may exhibit distinctions of mode and •
kind, analogous to those we have characterised as young
cell-division and old cell-division.

a. Without a nucleus? Ramification of Cladophora ,
Chantransia, Chroolepus, Draparnaldia, Chcetophora , &c.
In many of these genera the nuclei have certainly been
merely overlooked.

ß. TFith a nucleus. ITere belong the Fucoidese and
Florideae, in the ramification of which, according to
Nägeli’s conjecture,§ the original nucleus remains in the
cavity of the mother-cell, while a new nucleus is formed
in the protrusion becoming the branch-cell.

With these “ baggings-out” of the cells, giving origin
to the branches of the lower plants, may be compared,
to a certain extent, the thglls, those remarkable cell-like
structures which fill up the wide vessels of wood in old

* Hofmeister, 1. c., p. 6.
t lbid., p. 36, t. xii, f. 9 — 14.

% lbid., p 22, t. ix, f. 9—14.

§ ‘Zeitschr.,’ 1847, pp. 71, 72, (Modes of Cell-formation, 8 a and b.)
(Ray Transl., 1849, pp. 141, 142.)

254

THE PHENOMENON OP

age, and, according to the researches of an anonymous*
author, sprout forth as little utricular protrusions from
tlie cells of the surrounding tissue, and penetrate through
the thin-walled canals of the dots into the vessels. In
these thylls, whieli appear quite as true, partial, and local
Rejuvenescences of tlie cells, nuclei are formed at a time
when tliose of the inother-cell have long since vanished,
never becoming renovated.

2. Shutting-off of a daugliter-cell in tlie domain of
frucüfication. The shut-off and detached daughter-cell
becomes a spore, wliile the mother-cell remains vegetative.
This case doubtless occurs in the spore-formation of many
Fungi, particularly the true Hymenomycetes,f many
Gasteromycetes4 and most Hyphomycetes.§

Tlie multiplication of the cells in the Algal genug
Exococcus (Nägcli, ‘Algcnsyst/ 169) and the fermentation
Fungi, || also takes place by the shutting off, and fre-
quently complete tying-off (Abschnürung) of either
’ terminal or laterally budding daughter-cells. But as all
the cells are of likc character here, these cases would be
morc propcrly referred to the domain of vegetative cell-
formation.

c. Reconstruction, with Division into four
daugiiter-cells. — From the pregnant discoveries of Ad.
Brongniart^f and H. v. Mohl,** on the formation of the

* ‘Untersuch, üb. die Zclleuartig. Ausfüllung, der Gebisse,’ (‘ Bot. Zeit.,’
1845, pp. 225, 241, t. ü.)

+ See Phocbus, ‘Ub. der Keimkornerapparat, der Agaricen,’ &c., ‘Nov.
Act. Nat. Cur.,’ xix, 11, (1842,) p. 171, t. 5G, 57. Corda, ‘Ic. Fung.,’ iii,
t. 7—9 ; iv, t. 10, figs. 134—139; v, 1. 10.

+ See Tulasne, ‘ De la Fructification des Scleroderma comparec ä celle des
Lycoperdon et JJovista,’ ‘Ann. des Sc. nat.,’ 17, (1842,) p. 5, t. 1, 2, ‘Sur
les Genres Polysaccum et Geäster ,’ ibid. 18, (1842,) p. 129, t. 6.

S See Schleiden, ‘ Grundz.,’ ii, pp. 38, 39, figs. 106, 107, (‘ Principlcs,’
pp. 153, 154, figs. 122, 123; Corda, ‘Ic. Bung.,’ ii. t. 10, fig. 68, ( Verti -
cillium; ) iii, t. 1, fig. 23, ( Botrytis ) ; iv, 1. 10, fig. 132 (Isarici).

II See Saccharomyces Cerevisice , in Meyen, ‘Pflanzen-physiol.,’ iii, p. 455,

t. x f 22.

‘ Sur la Generation et le Developpement de l’Embryon,’ ‘ Ann. des Sc.
nat. ’ 1827.

** ' Ueb. der Bau und die Form der Pollenkörner,’ (1834); ‘Ub. die
Entwicklung und den Bau der Sporen der Kryptogamische Gewächse,’
(‘Flora,’ 1833,) ‘Vermischte Schriften,’ p. 67.

REJUVENESCENCE IN NATURE.

255

pollen-grains of the Phanerogamia and the spores of the
Cryptogamia, the formation of four daughter-cells in each
mother-cell appeared to be a case of very frequent occur-
rence, widely diffused in the condition of transition to
fructification. From more recent researches, however, on
the processes which precede the formation of both the
pollen-grains and the groups of four spores,* in the mother-
cell, the nature of the formation is not so simple as it at
first appeared. The pollen-grains and spores are not
formed immediately in fours in the mother-cell, but singly
in special mother-cells, so that the origin of the number
four is to be examined in the latter. According to
Nägeli’s researches, this takes place in two ways.f The
mother-cell either divides at first into two daughter-cells
(primaryspecial mother-cells), which then each divide again
into two (secondary special mother-cells) ; or the mother-
cell divides immediately into four daughter-cells, in which
case, consequently, only one generation of special mother-
cells (merely primary) is formed. Only the second case
belongs to the present section of our subject. From
researches hitherto made, it seems to follow that in the
first mode of origin the group of four (secondary) special
mother-cells are usually placed in one plane ; in the latter
the four (primary) special mother-cells in two planes,
or in the order of the angles of a tetrahedron. If this
relation of the arrangement to the mode of origin were
constant, it would be an easy means of ascertaining the
direct or indirect formation of the group of four special
mother-cells, at a later epoch, from the arrangement, nay
even in many cases from the form (in a great measure
dependant on the original position) of the spores or
pollen-grains.]: But this relation is not constant. Ac-

* Here belong the formation of the species of the Ferns, Mosses, and
Hepaticae ; both kinds of spore-formation in the Lycopodiacea;, Isoetaceae,
and Ithizocarpcae ; and one kind of spore-formation in the Florideae.

‘Zur Entwick. des Pollens der Phanerog.,’ 1842.

: : Quadratic (situated in one plane) position and elongated form of the
pollen-grains occurs priucipally in the Monocotyledous ; tetrahedral position
am roundish form almost universally in the Dicotyledons, (Molil, 1. c., p. 34.)
Both cases are likewise repeated in the spores of Ferns, the former (longish

256

THE PHENOMENON OF

cording to Nägeli’s* observations (on the forraation of
the pollen of Lilium), tlie tetrahedral arrangement of the
four special mother-cells occurs also when they are
formed in the second generation, when the two primary
special mother-cells first, prodnced are divided, not in the
sarne, but in a different direction, producing a decussating
arrangement of the two pairs.t On the other liand, it
follows from Hofmeister’s description of the formation of
the pollen in Firnis, \ tliat four special mother-cells lying
in one plane maybe produced by simultaneous formation.
But what seems to us of still more importance liere, is
the observation, tliat not merely the various modes of
arrangement, but even the cases, which we should suppose
very essentially different in their mode of formation, of
primary and secondary, direct and in direct formation of
special mother-cells, are not exclusive of eacli other in
their natural occurrence, since they sometimes occur in
substitutive alternation in one and the same plant.
Niigcli has named Althcea rosea as a plant in which the
special mother-cells are formed in one generation (four
at a time), and also sometimes in two successive gene-

shape, willi a longitudinal keel,) c. g., in Poly podium vulgare, Ceterach
officinarum , Asplenium lluta muraria , Aspidium Füix femina, &c. ; the latter
(producing the form of a triangulär pyramid rouudcd at the base,) in Pteris
longifolia , serrulata, Allosorus crispus , Noloclilcena marantce , Osmunda regalis,
& c. (H. von Mohl,’ ‘ Yerm. Schrift./ G9, 70.) In the Mosses and Hcpaticai
the tetrabedral arrangement seems to be predominant, likewise in the Lyco-
podiaceie and lthizocarpem, in the latter of which tliis is indicated by three
short lines united in the form of a tripod, botli on the small aud imperfectly
developed large spores, (Mettenius, ‘Beiträge zur Kenntniss der llliizo-
carpeen/ t. i, of Salvinia.) In the Floridese there occurs a third mode of
arrangement, in addition to the quadratic aud tetrabedral, namely, the linear,
(Kütz., ‘Phyc. gen./ p. 100,) “spermatidia quadrijuga.” See, forinstance,
t. 60, iv, Hypnophycus musciformis, and t. 62, iii, Calliblepharis ciliata.

* Nägel i, ‘Entwick. des Pollens/ p. 18, t. ii, f. 19, 20, 21.

f The shape of the four secondary special mother-cells, (and consequently
of the pollen-grains or spores,) is in tliis case, however, different from that
in the tetrabedral arrangement through direct formation ; in the former case
the four portions, (as in the quadratic arrangement,) have the form of quarters
of a spherc, in the latter the form of a three-sided pyramid with a rounded
base. If the two modes of arrangement require to be distinguished, the
former may be called the decussate, the latter the pyramidal or tetrabedral
in a restricted sense. (See also Nägeli, ‘Neueren Algensystcme/ p. 190.)

J ‘Bot. Zeitung./ 1848, 671.

REJUVENESCENCE IN NATURE. 237

rations (two and two). Hofmeister mentions the opposite
case as occurring in Tradescantia, in which the special
parent-cells are usually formed two and two (in one plane
or decussating), sometimes, however, all four simul-
taneonsly (in tetrahedral position).* This remarkable
eircumstance indicates an intimate connection of the two
cases, to which we are still more definitely attracted by
certain observations on the behaviour of the nucleus
before the direct quartering. In the first place, we must
here recall the remarkable course of development of the
spores of Anthoceros, described by H. von Mohl,f and
also by Nägeli.j; At the sides of the central nucleus of
the mother-cell, here, as an exc.eption, not vanishing, two
new nuclei are formed (called by Mohl, from their
granulär contents, “ granule-cells”), which after some
time divide, thus producing four nuclei, which, gradually
retreating from each other, assume a tetrahedral arrange-
ment. Around these four nuclei the special mother-cells
are simultaneously formed, by division of the entire
contents of the general mother-cell. Still more expressive
are the observations made by Hofmeister on the forrna-
tion of the pollen of Pinus .§ The large nucleus becomes
dissolved ; two secondary nuclei are formed ; between
these two the granulös of the cell-sap accumulate as an
annular zone at the equator of the cell ; the zone of
granules soon splits into two parallel zones, indicating
the Separation of the primordial utricle into two halves.
Up to this point all the mother-cells behave alike, but
the subsequent development takes place in two different
ways. Either the indicated division into two primary
special mother-cells is carried out, and two secondary
special mother-cells are formed again in each of them ; or
the commencing halving of the primordial utricle is inter-

* ‘Bot. Zeit.,’ 1848, p. 430, t. iv, f. 22—25.

t ‘ Ueber dieEntwick. der Sporen von Anthoceros tcevis,’ (Linnsea, 1839 ;)
‘Yerm. Schrift./ p. 84, t. iv.

\ ‘ Zeitschrift,’ 1844, pp'. 49—54, t. i, f. 31—40. (Ra.y Transl., 1845,
pp. 229 — 233, t. vi, fig. 31—40.)

258

THE PHENOMENON OF

rupted, the two secondary nuclei vanish, and in place of
each one of them appear two tertiary, making four nuclei
in a cell, which either lie in one plane, or are arranged
like the angles of a tetraliedron, and the formation of the
four special mother-cells now takes place directly around
these. Supported by these observations, we might cer-
tainly conjecture, that all those processes of cell-formation
which, according to the externa! clefinition of the cells,
appear as direct quarterin gs, are essentially the same as
the double halving, only distinguished from the latter by
skipping over one stcp of the course of the formative
process, advancing, namely, from the first halving,
already indicated by the formation of two secondary
nuclei in the interior of the cell, without completing tliis,
to the succeeding halving.

ln the multiplication of the Unicellular Algac, especially
in the family of the Palmellacepe and those nearest allied
to them, we meet witli undoubted cases of true quartering
(in the sense just explained), together with apparent
quartering. The latter results from the first halving,
which produces merely a transitory generation of cells,
being followed immediately by a second.* Here also
the arrangement of the cells in one plane not unfrequently
alternates with the decussate, as I have observed, for
example, in Clilamidococcus pluvialis. Nägeli gives
genuine (and tetrahedral) quartering as the character of the
genus Tetrcichococcus , the independence of which he, how-
ever, doubts himself, placing it as a sub-genus under
Pleurocococcus, and leaving it undecided whether the form
of Alga thus characterised does not belong to Pl. vulgaris. f
I have observed intermingled, in Protococcus viridis , mere
halving, apparent (decussating) and true (tetrahedral)
quartering ; the latter two distinguishable by the form of
the cells, from which alone I could draw inferences as to
the mode of formation in this case.

* I have already directed attention to the circumstance, above,(p.l60, note.)

f Nägeli, 1 Zeitschrift,’ 1847, p. 70, (Kay Traust, 1849, p. 140,) ‘Neuer.
.Algcnsyst.,’ p. 127.

REJUVENESCENCE IN NATURE.

259

d. Reconstruction with Division of the contents

OF THE MOTHER-CELL INTO AN INDEFINITE NUMBER OF

daughter-cells. — The cases to be mentioned here all
belong to the fructification of the Algae, Lichens, and
Fungi; they have hitherto been included, especially by
Nageli, not under cases of cell-formation by division,
but of free cell-formation, from which, however, they are
essentially distiuct. While, in free cell-formation, the
mother-cell, notwithstanding the formation of daughter-
cells takiug place in it, preserves its own vitality, that is,
continues to exist as a living cell, consequently possesses,
in addition to the daughter-cells, vitally active contents
bounded by the persistent primordial utricle, and often
still furnished with a well-preserved nucleus ; — in the
cases to be examined here, as in all formation of daughter-
cells by division, the mother-cell dies at the very first
formation of daughter-cells : which is especially indicated
by the constant dissolution of the primordial utricle of
the mother-cell. The entire contents of the mother-cell,
at most with the exception of a watery fluid containing
but few organic constituents, become applied to the
formation of the daughter-cells, and not by actually
existing daughter-cells gradually consuming it, but in
such a way that the whole contents (so far as available
for reconstruction) are divided among the daughter-cells
at the earliest definition of the boundaries of the latter.
Hence the cells do not originate with free bounding
surfaces, but in original contact both with each other
and with the wall of the mother-cell; but they may
separate subsequently, or, if the watery contents of the
mother-cell are excluded from the new structure, even at
the first completion of their formation.

1. The daughter-cells are formed by the division of
contents filling the entire cavity of the mother-cell. —
This case presupposes that the whole contents are
mucilaginous, and capable of sharing in the process of
reconstruction.

a. The daughter-cells lie in one roio in the mother -

260

THE PHENOMENON OF

cell. — The cylindrical cell of Sciadium (see p. 187) pos-
sesses miiformly distributed green contents, which are
interrupted in perfectly developed cells by light cross
streaks, and are divided into a row of 5 — 8 about equal
ruasses, which become gonidia. I could not detect
nuclei in the individual segments of the contents passing
into the formation of gonidia. Probably the conditions
are similar in Ophiocytium (Näg. ‘Einz. Alg. iv, a). It
seems to nie probable tliat the formation of spores in the
cylindrical or fusiform mother-cells (asci) of the Lichens,
Pyrenomycetes, and Liscomycetes, belongsto this kind of
cell-formation. The greater concentration of the con-
tents which accompanies the formation of resting spores,
canses the exclusion of the watery portion of the contents
of the mother-cell, and hence a detaclied position of the
spores presenting itself in the earliest period of their
isolation. The development of the spores of Peziza
Acetcihdum , as described by Corda,* leaves scarcely a
doubt in this respcct. In the ecpiably difliised, opake,
and granulär fluid contents of the mother-tube is formed
a row of globular structures, Standing at regulär dis-
tances, called by Corda drops of oil, which, from their
relation to the subsequent formation of the spores, appear
to be nuclei. Around these nuclei a lighter atmosphere
is formed, the darker granulär mass accumulating in the
form of zones between them : which reminds us of the
analogous plienomena in Hydrodictyon , and in the forma-
tion of the pollen of Pinus and Passiflora. Soon after
this, the individual globular nuclei appear surrounded by
masses of contents and membranes, consequently as the
central structures of so many longish spores, which are
separated by a light, watery fluid, containing but very
few granules.

b. The dauyhter -cells fdl vp the mother-cell irregu-
larly. — I think we may reckon here the formation of the
gonidia of Chlorococcus (according to Nägeli),f also of

* ‘ Icones Fungorum/ iii, p. 38, t. vi, figs. 95, 96.

f ‘Zeitschrift/ 1847, p. 23, (Ray Transl., 1849, p. 96,) ‘Einz. Alg./
p. 17.

REJUVENESCENCE IN NATURE.

261

Chytridium (p. 185), in which genus the nuclei scattered
tlirough the whole contents of the mother-cell, are clearly
distinguishable before the formation of the boundaries of
the gonidia. Perhaps the formation of the spores of
many Pungi, in particular the genns Erysiphe* belongs
here.

2. The daughter-cells are formed hy the division of a
mucilaginous layer coating the inside of the wall of the
mother-cell. — Since this by no means very rare mode of
cell-formation — to which the term “ parietal cell-forma-
tion wonld seem apt, were it not already used in another
sense — has never yet been acurately described, I shall
give a somewhat detailed account of it, as I observed
step by step in the formation of the gonidia of Hydro-
dictyon. I have already spoken of the stränge mode of
reproduction of the Water-net (pp. 137, 222); and
the cliaracters of the cell-contents (pp. 171, 197) and
the cell-membrane (p. 190), before the commencement
of reproduction, have also been explained ; so that,
taking up the subject at that point, I may commence
immediately with the description of the phenomena
tlirough which the beginning of the formation of gonidia
is announced. The first stage, introducing the formation
of the gonidia, comprises the period of solution and dis-
appearance of the starch-grains. The mucilaginous layer
{i. e. the more consistent, formative contents resting
against the cell-membrane, the subordinate divisions of
which have been described above, and which retain their
parietal position up to the completion of the formation of
the gonidia) changesits aspectin a remarkable manner at
this period. The fresh transparent green becomes more
opake, and the entire mucilaginous layer acquires, even
before the solution of the starch-granules is completed, a
peculiar, regulär appearance, closely beset with lighter
spots, which appearance, however, is only distinctly per-
ceptible when the focus is adjusted to the bottom of the

* See Corda, ‘Icon. Fung.,’ ii, t. xiii, f. 100.

2C2

THE PHENOMENON OF

mucilaginous layer. These spots are not the starch-grains
undergoing solution, as might be conjectured, for their
number is much larger than that of the latter, the not
quite lost nuclei of which may still be remarked here
and there, and not in, but between the spots. The little
green granules of the contents, which, for the sake of
brevity, I shall call chl orophy 11-gran ules, * do not disap-
pear with the starch-grains, but separate from each other
at the period of the formation of the spots, and becorae
accumulated as darker boundary lines between the
brighter spots. By adjusting the focus up and down we
may ascertain that scattered chlorophyll-granules occur
also above and beneath the light spots, while the spots
themselves are roundisli spaces, free from granules,
existing in the thickness of the mucilaginous layer.
Simultaneously with thcse processes the green colour of
the mucilaginous layer passes more into a brownish,
a cliange of colour which sliows itself still more clearly
in the next stage, especially in those cells in which
microgonidia (swarmers) are to be formed. Still more
striking alterations present themselves in the seconcl stage
of the formation of gonidia, in which the mucilaginous
layer exhibits a picture diametrically opposed to that just
dcscribed. The granules retreating towards the bright
spaces, the earlier dark net-work of the granules is
replaced by a net-work of lighter boundary lines ; the
former bright spots, on the contrary, become darker areolae
through the collection of granules into groups. When the
new distribution of the contents is complete, the light inter-
mediate streaks appear as everywhere pretty equally broad,
light-yellowish (not green) lines, sharply defined upon the
dark field ; the latter displays little polygonal (mostly hex-
agonal, rarely pentagona! or heptagonal) green plates, with

* These granules are not chloropbyll-vesicles, as in Faucheria, Cliara, &c.,
they have more the aspect of dense, mostly longish granules, without any
enveloping membrane. When the Chlorophyll is extractcd by spirits of
wine, these, like the remainder of the contents, become bleached, but remain
distinguishable ; the shape, however, becomes irregulär through the action of
the spirit.

REJUVENESCENCE IN NATURE.

263

a more or less brownish tinge, sometimes appearing wbolly
filled witli granules, sometimes displaying a lighter space,
free from granules, in their centres. In correspondence
witli the shape and the (in the same mother-cell) tolerably
equal size of the plates, tliey are so arranged that mostly
six are grouped round a central one. The size of the
plates varies according as tliey are to form macrogonidia
(net-formers) or microgonidia (swarmers) ; in the former
case the diameter amounts to about ^th millim., in the
latter to ^th or -jigth ; the latter, moreover, exhibit a less
regulär, more oblique shape, and less numerous (only
4 — 10) Chlorophyll granules. The membrane of the
parent-cell begins to thicken by swelling-up in this stage.
In the third stage , finally, is effected the complete
Separation of the little plates, and the formation of the
gonidia. The plates, already previously clearly defined
against the light intermediate streaks, begin to round off
at the corners, and to become convex at the surface,
previously lying flat against the cell-membrane, so that
the tabular form passes, not at once into a globular, but
into a lenticular form, wliich compression may still be
observed in a slight degree subsequently, in the stage of
motion. Düring this rounding, the lighter intermediate
streaks vanish, the gonidia come into direct contact,
triangulär intercellular spaces only appearing at each
point wliere three meet. This stage is ordinarily of very
short duration, passing at once into the fourth, that of
the movement of the gonidia, which differs in degree and
duration, according to the kind and destination of these.
Although the phenomena of the motion of the gonidia of
Uydrodictyon have been spoken of already, we cannot
pass them over entirely here, since certain points come
under consideration in it, which have an influence on our
judgment respecting the mode of cell-formation which we
are now engaged witli. Both in the macrogonidia and
microgonidia the movement at first presents a mutual,
originally scarcely perceptible crowding and pushing,
which, when in full course, is comparable witli the move-

264

TUE P 1-1 EN OM EN ON OE

ment of a clense crowd of people in which no one can
leave liis place. The signal for freer and more active
motion is given by the processes taking place about this
time in the membrane of the mother-cell. The cell-
membrane has begnn to thicken even in the second stage
of the formation of the gonidia, and the swelling-up
made still further progress in the third, but the resist-
ance of the cuticle hinders the extension of the circum-
ference of the cell-membrane. This obstacle is now
removed by the cuticle Cracking, first in one, and soon in
several places, which gives the cell-membrane, now
becoming soft and limp through the swelling-up, room to
expand. This is the epocli in which the movement of
the gonidia changes, eitlier siraultaneously throughout
the cell, or more frequently gradually spreading from the
spot where the first dehiscence of the cuticle occurred,
into a lively trembling and jerking, which Treviranus not
inaptly compares with the ebullition of boiling water.
But even in this very rapid motion the actual locomotion
of the gonidia is extremely slight, so that, for example,
free spaces, such as occur in cells where vacuities existed
in the mucilaginous layer, are not filled up by gonidia.
In the macrogonidia, destined to form nets, the motion
stops liere; in the microgonidia, on the contrary, a
whirling is added to the trembling motion. . While,
namely, up to this time, the whole mass of microgonidia
had retained tlicir peripherical position, representing as a
whole the form of a sac, corresponding to the form of the
mucilaginous layer, even in their movement, this stränge
bond is now dissolved, the gonidia leave the periphery,
and whirl about in varied intermixture through the
whole cavity of the cell, tili at length, through the
bursting of one or more bulging protrusions of the cell-
membrane, they leave the cell in a dense swarm, and
continue the swarming motion for a long timein freedom.
Both the macrogonidia and microgonidia exhibit various
peculiarities, during the period of motion, which were
not perceptible before its comraencement. The macro-

REJUY KNESCENCE IN NATURE.

265

gonidia retain their roundish or rounded polygonal form,
but exhibit at one side a hyaline margin, whicli occupies
about a third part, or even half of the circumference ;
the microgonidia, on the otlier liand, become distinctly
longish, the more acuminated end, at the same time,
appearing transparent. The green grannles enclosed in
the interior are still distinguishable in both, but less
sharply, since they begin to blend together ; the colour
is again bright green, in the net-formers darker, in the
swarmers more of a yellowish-green. The jifth stage,
that of rest, is connected in the macrogonidia witli their
union into a young net, which union begins even in the
last period of the movement, so that gonidia, already
united in groups, are seen still jerking and pulling back-
wards and forwards. When they have come to complete
rest, and united perfectly into a new net, the elongation
of the previously roundish gonidia begins ; the green
granules in their interior become completely blended into
a homogeneous mass; the rudiment of the first starch-
grain makes its appearance ; the newly formed cell-mem-
brane becomes distinguishable. The microgonidia, also,
which swarmed-out, and which never unite into nets, but
merely become irregularly heaped together, exhibit, after
they have come to rest, this transition of the granulär
contents into a homogeneous green mass, as well as the
formation of a small starch-grain and the production of a
distinct cell-membrane, by means of which they often
become coherent together in groups ; on the other liand
they show no trace of elongation, and in general do not
increase in size,* while in the young nets the increase of

* I cannot let this opportunity pass without mentioning one observation,
which perhaps somewhat modifies what has been said above. In the vessels
of water in which I cultivated Jlydrodictyon I frequently found isolated
Ilydrodictyon- cells, in groups of l'our united irregularly together, which
became developed, but under these circumstances assumea irregulär, bulging,
nodulated, or even branched forms. Whcther these hermits arose rrom
individual microgonidia, which, as an exception, had arrived at a develop-
ment, or from macrogonidia scattered through accidental rupture of the
mother-cells in the stage of motion, I could not decide by direct observation.

266

THE PHENOMENON OF

sizö advances with astonishing rapidity, tlie cells of the
net, under favorable circumstances, increase to 600 times
tlie length, and 240,000 times tlie volume in tlie course
of a few weeks.*

After tliis description of tlie pröcesses taking place in
tlie course of tlie formation of tlie gonidia of tlie Water-
net, it is not difficult to perceive its similarity to otlier
niodifications of cell-formation by division. Seeking, in
the first place, tlie import of tlie light spots wliicli
characterise tlie first stage of tlie new cell-foi’ination of
tlie Water-net, it is beyond donbt tliat tliey represent the
centres of so many new cells, conseqnently are either
actual nnclei, or, since we cannot detect any defined
outlincs, accumulations of albiiminons snbstance analo-
gous to nnclei. The net-work of grannles between the
light spots, occnpying the bonndary-lines of the future
gonidia, rcminds us of tlie formerly mentioned prodnction
of a zone or plate of grannles, appearing in the division
of the mother-cells of pollen, as also of the zones of
grannles in the mother-cells ( asci ) of the spores of
Pcziza, and shows tliat the regions becoming parted off to
form new cells are in contact at first. The light streaks
which are displayed in tlie second stage, between the
concentrating and isolating tabular portions of the Con-
tents, appear to be formed by a secreted matter, which is
immediately re-dissolved and destroyed, but which effccts
the solntion of continnity between tlie individual gonidia,
and between them and the membrane of tlie parent-cell.

but tlie latter scems to me more probable. I bave also observed similar
liermits iu Pediastrum.

* The entire development of tbe Water-net to the period of repetition of
the formation of gonidia, is completed in about 3 — 4 weeks in cnltivatcd
s]ieciineiis; in the wild state, with more vigorous Vegetation, a longer time
may perhaps be necessary. The size of the cells at the period of the pro-
duction of the net, at which time their shape is elinost globular, amouuts to
T£0 millira.; the fully developed cells frequeutly exliibit, iu the wild state, a
length of 5 — 6 millimetres, a thickuess of £ — l mill. ; wlien cultivated in-
doors, on the contrary, they attaiu ouly 1— H mill., in subsequent geuera-
tions even only \ \ mill. in length, but the propagation, ncvertheless,
happens at the proper time.

REJUVENESCENCE IN NATURE. 267

Perhaps it is the same substance in a state of solution,
but still viscous, which retainsthe active gonidiafor sorae
time at the periphery of the cavity of the mother-cell, so
that the macrogonidia, in which the stage of rest and
mutual attachment begins pretty soon, cannot unite
otherwise than in the tubulär form given by their mode
of origin, into a net-like colony. We sometimes perceive
in the interior of newly-formed nets, still enclosed in the
membrane of the parent-cell, colourless balls of muci-
laginous consistence, without distinct outlines, which are
coloured yellow by iodine. In the swarm-like escape of
the microgonidia, through the burst dehiscence-sacs of
the mother-cell, likewise, we sometimes see the swarm
interrupted by a mass of mucilage mixed up with and
clogging them. Whether these masses of mucilage are
the still undestroyed remains of the above-mentioned
secreted conuecting substance of the gonidia, I do not
venture to decide. Ordinarily, after the complete for-
mation of the gonidia, the contents of the mother-cell
exhibit, besides the gonidia, nothing but water-clear
fluid.

As a proof that the gonidia of the Water-net do not
originate free in the contents of the mucilaginous layer,
but separate from one another by mutual demarcation of
boundaries, out of an originally continuous mass, I may
mention the not unfrequent occurrence of twin-gonidia
(even of triple groups) in which, on swarmers, two (or
three) ciliated points may be distinguished, which are
sometimes side by side, sometimes placed at right angles
to each other, or are even on directly opposite sides. It
is easy to make certain that such forms are not produced
by biending of previously separate gonidia, but that the
light line of division, as formed in the second stage, is
omitted between the two plates or groups of contents ;
that, consequently, the mutual external definition be-
tween two (or three) inwardly separated cells, has not, or
only imperfectly, been cffected.

The formation of the gonidia of Ascidium (p. 128),

268

THE PIIENOMKNON OF

Cladophora, and probably also of Chatomorpha (p. 185),
agrees essentially with the mode of cell -form ation here de-
scribed ; raoreover, judging from the Statements of anthors,
those of Endococcus (Nägeli, ‘Einz. Algen./ p. 17) and
Bryopsis, in wliich genus the accurate tracing of the pro-
cess, especially in reference to the behaviour of the Chloro-
phyll vesicles,would be especiallyimportant. The formation
of the gonidia, as well as the spores, of Saprolegnia,
likewise referring here, deserve a more minute exami-
nation, on acconnt of their somewhat aberrant character.
The apices of the filaments, swelling up into longish clubs
or cylinders, and becoming shut off as separate cells, in
wliich the gonidia of Sciproleynia are form cd,* are filled
at their formation with a granulär mucilage. Subsequently
several cavities present thcmselves in the inferior of the
mucilaginous mass, along the axis of the club, wliich
cavities, gradually increasing in size, become blended
into a single cavity traversing the entire tube, not, how-
ever, of very large size. The contents tlius converted
into a t h ick parietal mucilaginous laycr, soon acquire an
undulated surface, forming little rounded eminences,
wliich project more and more, while the intermediate
furrows continually cut in decper until tliey at length
reacli the cell-wall. In tliis manner the mucilaginous
layer becomes divided into numerous hemispheres, at-
tached by their flat sides upon the cell-wall ; these,
however, immediately become rounded into globules,
separating simultaneously from the cell-wall. Tliis com-
pletes the formation of the gonidia, wliich immediately
commence their movement, cont.inuing it for some time
after tliey liave been expelled from the mother-tube.

* The formation of free sporangia in the inferior of the swollen points of
the filaments, described and figured by Nägeli, (* Zeitschr.,’ 1847, p. 28,
t. iv, figs. 1— ö,) is totally different l'rom tliis. I liave likewise seen it, so
rarely, however, tliat I could not trace the wliole course. It seemed to me
not to bclong to the spliere of the normal phenomena of development of
Saprolegnia , and is just as enigmatical as the occurrence of scssile globular
excrescences with rotating and subsequently rcpeatcdly dividing contents,
observcd in the same plant.

REJUVENESCENCE IN NATURE.

269

Düring the time tliey are in motion, the gonidia exliibit
a longisli sliape, in the transition to rest tliey re-acquire
the original globular form. The rest is followed im-
mediately by germination. All these processes, from the
formation of the clubs to the swarming out of the gonidia,
are the work of a fevv liours.* The occurrence of large
resting spores, vvhieh has escaped most observers,f is a
normal phenomenon in the later period of the existence
of Saprolegnia, occurring sometimes simultan eously with
the formation of the gonidia, usually, however, after that
is terminated. The spores are formed in globular or
pear-shaped, expanded cases, at the tips of slender
divaricated lateral branclies ; the tips of the erect shoots
more rarely swell up into such bulging spore-cases. In
exceptional cases spores are formed also in cylindrical
terminal tubes, agreeing in form with the gonidium-
cases. The mode of formation of the spores agrees in
all essentials with that of the gonidia. The granulär
mucilaginous contents of the future spore-cases become
darker and more opake than those of the gonidium-clubs,
but, as in them, become applied upon the wall of the cell.
In this stage several large vesicles, arranged at regulär
distances, make their appearance in the dark mass of the
mucilaginous layer.

When we compare the number and distance of these
vesicles with those of the future spores, it scarcely admits
of doubt that tliey are nuclei, from which proceeds the
formation of the spores, especially since we may often
distinguish a similar lighter vesicle in the developed
spores. The formation of nuclei is followed by the
production of elevations on the internal surface of the

* The statement of Meyen, (‘ Pflanzen-physiologie,’ iii, p. 457, 1. 10, f. 19,)
that the active gonidia are formed in separate mother-ceüs inside the club, is
incoinpatible with my observations. Perhaps tlie key to this difficulty lies
in the above-roentioned observation that the gonidia of Saprolegnia capituli-
fera acquire a niembrane shortly after birtk, (see p. 188.) It is conceiv-
ablc that Meyen’s observation was made on another peculiar species in
which the gonidia acquire a niembrane even before birth.
f I find it mentioned only by Schleiden, (‘Grundz.,’ lte Aull., ii, p. 36.)

270

THE PHENOMENON OE

mucilaginous layer. The somewhat distant elevations
becorne more and more rounded, and the mucilaginous
layer, drawing itself apart between them, becomes finally
wholly contracted iuto them. The hemisplieres thus
formed are therefore uot closely crowded, as in the
formation of the gonidia, but separated by largish inter-
spaces. The next process is the rounding and detachment
from the cell- wall, in consequence of wliich the spores lie
free and loose in the interior of the spore-case, and are
not scattered until this decays. The form of the spores is
alvvays globular ; the size varies in Saprolegnia prolifera
from so to jö uiilhm., while the gonidia in the stage of
motion are only milim. long ; the colour is brown ; the
contents are at first fincly granulär, subsequently inter-
mingled with drops of oil ; the membrane is at first
imperceptible, when fully developed thick and evidently
double. In the cylindrical spore-cases, the hemispherical
elevations are formed in pretty regulär alternate order ou
the two opposite sides of the cell-wall, so that they are
interposed like the teetli of two wheels or racks • but
the detachcd spores fall into a single linear row. In the
expanded cases the arrangemcnt of the spores does not
exlhbit any definite order. The uumber varies very
mueh according to the size of the cases. I liave seen as
many as twenty spores in one case, while in many other
instances there were only four, three, two, and not very
unfrequently there was only one.

The formation of the spores of Leptomitus lacteus
resembles that occurring as an exception in the cylindri-
cal cases of Saprolegnia; the spores detached from the
wall of the mother-tube are arranged in a single row.*
The formation of the spores in the sporangia of Coleo-
clicete takes place in a manner similar to that in the

* Leptomitus lacteus is in every respect allied to Saprolegnia. The diclio-
tomous filaments are not articulated any more tlian those of Saprolegnia,
but only divided into sections by regulär strictures ; thesc sections liave
been taken for closed cells. It is only in the fructification that isolated,
mostly terminal sections are actually shut off, swell up to some extent, and
become spore-cases. No active gonidia seem to occur.

REJUVENESCENCE IN NATURE.

271

globular cases of Saprolegnia. The spores are flat-
compressed, however, before their Separation, longish
afterwards ; their colour is green at first, subsequently
brown. The number of spores in C. pulvinata amounts
to 5 — 8.

Finally, I mention here the formation of spores in
Spfusroplea, already described (see p. 164),* as a case
which connects the two sections d. 1. and d. 2., the
formation of an indefinite abundance of new cells through
transformation of contents filling up the entire cavity of
the cell, on the one hand, and of contents excavated into
a parietal investment, on the other. Before the com-
mencement of fructification, the cell-contents oiSpluzroplea
represent a parietal investment, which, however, does not
maintain itself as such in the preparatory stage of forma-
tion of the reproductive cells, as in the foregoing examples,
but collapses entirely, whence the spores produced by its
transformation are not seated upon the cell -wall even in
their earliest state, but lie free in the cavity of the cell,
arranged, according to the proportion of their size to the
diameter of the long tubulär mother-cell, either in one
row, as in Sph. Leibleinii, K., or in two or more, as in
Sph. Trevirani, K.f and Braunii, K. From the position
of the spores, it would be more correct to apply the term
free cell-formation to this, than to the preceding cases ;
but even here it is the entire contents, with the mere
exclusion of a watery fluid, which break up into a num-
ber of newly individualised masses. That these masses
separate at their first production, only loosely fill the
mother-cell, and are little oy not at all in contact, arises
from the condensation of the contents connected with the
formation of resting spores, and the abundant quantity of
watery fluid which is tlius excluded. All the more con-
sistent portions of the contents, the viscid mucilage, the
previously annularly arranged Chlorophyll, with the

* (See also Presenius, on Spharoplca annulina, ‘Bot. Zeitung./ 1851,
vol. ix, p. 241. — A. Li.)

f Meyen, ‘ Pflanzen-phys.,’ iii, t. 10, f. 17.

272

TIIE PHENOMENON OE

extremely minute green granules in it, as well as the
starcli-grains* (not vanishing in the process of solution),
are taken up at the very first origin of the spores. They
are not gradually consmned, but enclosed in the first
structure, which also explains the phenomenon that the
spores do not comraence with minute rudiments, and
gradually increase in size in the mother-cell, but, on the
contrary, are larger in the first epoch of their formation
tlmn they are subsequently, when their mass has become
more Condensed. Thus this case appears as a reformation
of the whole cell-contents combined with di vision,
peculiarly modified by the condensation of the newly-
formed cells, and the retraction from the wall of the
mother-cell connected with this, a retraction such
as we have also seen in reconstruction without division
in the Spore of (Edogonium, or as we are acquainted with
in the family of the Zygnemaceae (in the intermixture of
the contents of two cells to form one spore).

e. Partial reconstruction througii Formation of

DAUGHTER-CELLS IN THE CONTENTS OF SURVIVING MOTHER-

cells. — Thiskind of cell-formation is distinguished from
all the preceding bythe circumstance that the mother-cell is
not lost in the reconstruction, but survives the formation of
the daughtcr-cells, the contents of the mother-cell being
only partially, not cntirely, applied to the formation of new
cells. While in all the foregoing cases the newly-formed
cells appear as more or less considerable transformations
of the mother-cell, we behold here a re-production or
new-formation in the most complefce sense, since the old
cell persists as such, in spite of the reproductions taking
place in it. In all the foregoing cases, nothing remains
of the mother-cell after the formation of the daughter-cells
but the inessential meinbrane ; here, on the contrary, we
see the daughter-cells enclosed in the living, undividedly
persistent contents of the mother-cell.

1. The daughter-cells originate {without a nucleus ?)

* Each single spore encloses several of the existing starcli-grains in its
structure.

REJUVENESCENCE IN NATURE.

273

dose to the cell-ioall, against which theg are firmly applied
during their completion. — This is the character of the
formation of the germ-cells of Valonia described by
Nägeli. In the long tubes, when full-grown measuring
| to U inch in length, of this unicellular marine Alga,
the organic contents form a thin investment to the wall,
while the large cavity is filled with salt water.* The
mucilaginous layer is beset with reticularly arranged
or scattered cldorophyll-vesieles. At particular spots,
especially at the bottom, more rarely in the apex of the
cell, are formed the germ-cells, sometimes singly, some-
times connected in groups. According to Nägeli, they
originate as minute colourless globules, wliich acquire as
they grow an evident membrane and green granulär
contents, chlorophyll-vesicles being formed in their in-
terior. The fully-developed germ-cells adhere as flattened
disks to the wall of the cell. Those which occur at the
upper end of the mother-cell usually germinate in the
still surviving mother-cell, breaking through its mem-
brane, probably locally soften ed, stopping up the orifices
agäin with their bases. The peculiar ramification of
Valonia arises from this growth of the young individuals
out of the old one. The germ-cells at the lower part of
the tube, remaining undeveloped, probably only becorne
free through the decay of the parent individual, to be-
come developed as separate individuals forming new
family-stocks. The case here mentioned is distinguished
from the mode of cell-formation minutely described in
Hydrodidyon , under d. 2, by the circumstance that only
particular points, and not the whole of the parietal
mucilaginous layer, passes into new cell-formation ; more-
over that the new cells exhibit a gradual increase in size
in the surviving mother-cell, while in Hydrodidyon they
attain at their first production the full size which they
are destined to acquire inside the mother-cell. Nägel i’s
description affords rio Information as to the behaviour of

* ‘Neueren Algcnsyst.,’ pp. 155 — 157, t. ii, f. 7 — 24.

18

274

THE PHENOMENON OF

the Chlorophyll- vesicles on those parts of the wall of the
mother-cell where the formation of the germ-cells occurs.

Botrydium doubtless belongs to the same family as
Valonia. My observations on the formation of the germ-
cells of this gen us, already mentioned (pp. 128, 193), are
not sufficiently complete to decide whether it can be
properly cited as an example here. In Botrydium the
germ-cells are sessile all over the inside of the wall of the
vesicular epigseous portion of the cell, placed pretty close
together, yet not in contact. They exhibit a rather con-
sidcrable difference of size in the same individual, which
seems to indicate a growth inside the mother-cell. Simul-
tancously witli their completion the mother-cell swells up,
softens, and collapses. According to Kiitzing,* however,
the spores often gcrminate before the collapse of the
mother-cell, breaking forth on its surface as a granulär
coating.

2. The daughter-cclls (mostly several, rarely only one)
are formed ( around nuclei ) free in ihe contents of the
mother cell. — The term “ free cell- formation,” which
certainly mects most of the modifications to be examined
here, has hitherto beeil applied to many other kinds of
cell-formation already treated above. Looking at the
mere words, we may use this cxpression in two very
different significations, according as we intend to call the
cell-formation free in its result or in its origin. In the
first sense we speak of free cell-formation in contrast to
the formation of connected tissue, under which circum-
stances the daughter-cells may stand originally in most
intimate contact with the mother-cell and with each other,
but not be grown together, or not so finnly that they
cannot finally become free by the rupture or resorption of
the mother-cell. We have seen such formation of free
cells under a. 2 (formation of the gonidia of (Edoyonium,
of the pollen-grains, &c.), b. 2 (formation of the gonidia
of Ulothrix , Ciaracium, &c.), d. 1 {ßciadium, Chytridium),

* On a new Botrydium, in ‘Nov. Acta.,’ xix, ii, 3S8, t. G9, 4.

llEJUVENESCENCE IN NATURE.

275

d. 2 ( Ascidium , Cladophora) . Free cell-formation in the
second sense, in which it was used for instance by
Nägeli,* likewise comprehends two very different series
of cases, viz., either the origin is only so far free, that the
daughter-cells formed through the transformation of the
whole contents of the mother-cell (with or without division
of them), separate at the very raoment of their Consti-
tution, frorn the membrane of the raother-cell, by con-
traction of their mass, and separate from each other in
the same manner, as we have already examined under
a. 2 (formation of spores of CEdogonium) , d. 2 {Spkrero-
pleo ) ; or the origin is free even in relation to the
defmition of the boundaries of the original mass of con-
tents from which the new cell is formed, the daughter-
cells being formed, not out of the whole contents of the
mother-cell, but out of the separate, unconnected portions
of them. It is this last series of cases that especially
merits the name of free cell-formation, if this term is to
be retained; and then the circumstanceswhether the newly-
formed cells are applied upon the mother-cell (e. 1), or
not, — and, in like manner, whether they subsequently
become connected together into a continuous tissue (as
we shall see in the endosperm-cells), or not, — are to be
regarded as less essential.

a. A free daughter-cell is formed around the primary
nucleus of the mother-cell. — The case here mentioned
differs from those examined under a. 2, e.g. the formation
of the pollen-grain in its special mother-cell, in the cir-
cumstance that the daughter-cell does not take in the
whole of the contents of the mother-cell, but lies free in
the contents of the latter, so that other daughter-cells
may subsequently originate in the contents of the same
mother-cell. This stränge and most rare case was

* ‘ Zeitschrift,’ 1846, p. 51, (Ray Translation, 1849, p. 123.) “In free
cell-formation a greater or smaller portion of the contents becomes isolaled , or
even the whole contents oftlie cell. On the surface of this is formed a complete
membrane, altogether free at its outer surface, (in contact neitlier witli the
wall of the mother-cell nor those of its sister-cells.)”

276

THE PHENOMENON OF

observed by Hofmeister in the embryo-sac of Funlcia
carulea * and described in the following manner. About
the time of the opening of the flower, before fertilisation,
but after the germinal vesicles have been formed, a new cell
is formed around the still existing primary nucleus of the
embryo-sac, which cell only occupies a small portion of the
internal cavity of the embryo-sac, in its lower third. After
the formation of this cell the original nucleus becomes dis-
solved, and two or more nucleus-like structures appear
in its place in the daughter-cell, but no furtker cells seem
to be formed around tliem. The formation of this central
daughter-cell belongs to the many structures occurring
in the embryo-sac which vanish again very quickly. The
same obscrver describes a similar process in the endo-
sperm-cells of Ornithogalum sulphuremn,\ in which, after
tliey have become parenchymatously connected, a new
daughter-cell not filling np the mother-cell is likewise
formed around the still present primary nucleus, which cell
sometimes becomes doubled by division, and around which
still other free cells appear subsequently to be formed.

b. Severalfree daug hier -cells are formed around newlg-
formed nuclei.\ — The nucleus of the mother-cell fre-
quently survives during the formation of free daughter-
cells of this kind, indicating persistent vitality in the
contents of the mother-cell by the mucilaginous radii
procceding from it. The number of daughter-cells
appears never to be accurately defined. All the cases
referable here occur in the embryo-sac of the Phanero-
gamia, in fact, it is doubtful whethcr anything similar
occurs anywhere eise in the development of plants. We
have to examine :

a. The formation of germinal vesicles — The embryo-
sac, or germ-sac, as it is terined, is the last cell of the

* Hofmeister, ‘ Die Enstehung des Embr. der Phanerog.,’ p. 13, t. viii,
f g 9 io. A similar phenomenon is described in Asphodelus luteus, p. 10.
t L. c., p. 14, t. xiv, f. 17 — 19.

x Hofmeister, 1. c., p. 11, is especially to bc consulted regarding the
origin of the nuclei themselves.

ItE J UV KNESCEN CE IN NATURE.

277

mother-plant, the uppermost in the axial row of cells of
the ovule, destined to become the focus of the reproduc-
tion, the mother-cell of new individuals ; the germinal
vesicles forming in it are the real rudiments of the new
individuals, the unicellular germs of new plants. They
are formed already before the period of the Scattering of
the pollen, free nuclei originating in the upper part of the
embryo-sac (the end turned to the apex of the nucleus
and the micropyle), in which the protoplasm is principally
accuinulated, around which nuclei soon appear sharply
defined masses of contents, which are, as it were, “ cut
out” of the general mass of contents of the embryo-sac.
The number of germinal vesicles is mostly three,* * * § rarely
more,f sometimes only two,{ and very rarely only one
exists, in which case, however, the larger number is indi-
cated at the earliest period of formation by their nuclei,
two of which disappear again without cells having been
formed around them.§ The newly-formed germinal
vesicles are roundish at first, but soon extend longitudi-
nally ; at first they are only slightly in contact, but as
they increase in size become crowded together more closely
in the upper end of the embryo-sac. Ordinarily only one
of them becomes developed into an embryo, this out-
stripping the others in growth even before fertilisation, ||
or the latter even die away and dissolve about that
epoch.^f At the period of fertilisation the germinal
vesicle destined to development presses its end lying next
the micropyle firmly against the inside of the wall of the
embryo-sac, against the outside of which the pollen-tube
is applied, which double connection may go as far as
actual growing together. In other respects the germinal

* Hofmeister, 1. c., Sorghum, t. xi, f. 22, 23 ; Canna, t. iv, f. 3, 5 ;
Godetia, t. v, f. 5.

f L. c., Funkia caerulea, p. 16.

+ H. c., P olyyonum orientale, t. xii, f. 18 — 20.

§ L. c., Agrostemma Githago, t. ii, f. 20 — 22.

|| L. c., Zea Mag s, t. xi, f. 4 ; Godetia, t. v, f. 5, 6, and ‘ Botanische
Zeitung,’ 1847, t. viii, f. 10, (Godetia.)

H H. c., Canna, t. iv, fig. G.

'278

THE PHENOMENON OE

vesicle remains wholly free during its development into
suspensor (vorkeim) and embryo, becoming developed
without any connection with the other phenomena of
cell-formation in the embryo-sac, even interfering with
and displacing and destroying thera, so that it affords ns,
not merely in its first formation, bnt also in its further
behaviour, the examplc of the freest and most inde-
pendent cell-formation whicli the plant exhibits.

ß. Formation of transitory cells in the embryo-sac. —
ln addition to the germinal vesicles not arriving at
development, already mentioned, other cells are met with
in the embryo-sac which only show themselves for a
short time; free cells, which are dissolved again and
vanisli without leaving a trace wlien scarcely formed, or
even before completion, as mere nuclei. Among tliese
are especially the cells presenting themselves at the lower
(chalazal) portion of the embryo-sac, agreeing more or
less in number and form with the germinal vesicles, but
never developing into cmbryos, and which are dcscribed
in Hofmeister’ s often-cited essay in the majority of the
plants investigatcd by him.* These stränge antipodes
of the germinal vesicle originate cither simultaneously
with the latter, or somewhat later, f and, in exceptional
cases, even carlier they mostly disappear again before
fertilization,§ often even as mere nuclei; in rarer cases
they persist for somc time after the fertilization, and
vanish during the formation of the endosperm-cells. ||
y. Formation of the endosperm throuyli free cell-
formation in the embryo-sac. — The vitality of the embryo-
sac is retained uninjured as a whole, in spite of the

* They appear to be absent from Polygonum orientale, (t. xii, f. 18, 19),
Agrostemma Gilliago (t. ii, f. 18—22) Godetia, (t. v, f. 4, 5); tbcy are
especially numerous in Sicyos (t. xiii, f. 3 — 5) ; often only a single one, but
of unusual size, presents itself in Hyacinthus orientalis (t. vi, f. 3).
f L. c., Orchis, t. ii, f. 2, 3, 4.
t L. c., Crocus, t. iv, f. 14.

^ L. c., JEcbalium, t. xiii, f. 6 — 9.

|| L. c., Hyacinthus orientalis, t. vi, f. 4, b ; Helianthus annuus, l. xiii,
f. 18—20.

UKJU VENESCENCE IN NATURE.

279

formation of germmal vesicles and transitory cells taking
place in both its ends ; its primary nucleus ordinarily
survives,* or even increases considerably in size after
the forraation of the germinal vesicles. f The nucleus of
the embryo-sac is only dissolved during or shortly before
the period of fertilisation, and then a profound recon-
struction commences in the interior of the embryo-sac,
expressed in the production of daughter-cells, likewise
free,| but so numerous that they soon exhaust the inde-
pendent life of the former, and the entire cavity becomes
filled up bythe cohering newly-formed cells. The tissue
produced in this way is the endosperm, or, as it is called,
the albumen of the seed, in whicli the developing embryo
of the new plant then becomes imbedded. The en-
dosperm-cells, like the germinal vesicles, originate as free
nuclei in the fluid of the embryo-sac, § which subsequently
become surrounded by masses of contents and clotbed
with membranes. The cells thus formed very soon com-
bine into a continuous parenchyma, in which there is no
longcr evidence of the origin from free cells. || The
cellular filling-up of the embryo-sac with endosperm-cells
is not however completed at once, but proceeds gradually
from the periphery to the centre, the successively formed
endosperm-cells applying themselves in layers upon the
inside of the wall of the embryo-sac. U The formation of

* L. c,., Sorghum, t. xi, f. 22; Hyacintlius, t. xiv, fig. 2; Erodium, t. iii,
f. 17 ; Helianthus, t. xiii, f. 17. More rarely the nucleus of the embryo-sac
vauishes before the formation of the germinal vesicles, e. g., in Orchis, t. i,

t L. c., Agrostemmu, t. ii, f. 18—22 ; Bartonia, t. ii, f. 31—10 ; Fritillaria
imperiulis, t. viii, f. 6 — 9.

+ The rarer case of formation of endosperm by cell-division has been men-
tioned previously, (p. 248.)

§ See Hofmeister’ s figures of Godetia, (‘Bot. Zeitung.,’ 1847, t. viii,
f. 25, a ;) Fritillaria imperiulis, (‘ Enstehung des Embryo,’ t. viii, f. 11 ;)
Fcbalium, (1. c., t. xiii, f. 11 ;) Helianthus, (t. xiii, f. 20 ;) Linum, (t. xiv,
f. 4, 8.)

|| See Schleiden, ‘Beiträge zur Botanik,’ t. vi, f. 69, 76, 77. (Erom the
albumen of Chanuedorea Sehiedeana .) (See trausl. in Taylor’s ‘Sc. Mem.,’
vol. ii, p. 281, t. xv, f. 1— 10.— A. H.)

See Schleiden and Vogel, ‘Heber das Albumen,’ ‘Act. Nat. cur.,’ xix,
u, t. 42, f. 42, 43 ( Tctragonolobus purpurcus,) and f. 49, 50 ( Baptisia

280

THE PHENOMENON OF

these layers appears to take place witli especial regularity
in the Gramin acese. According to Hofmeister’ s ob-
servations,* the nuclei imbedded in the mucilaginous
layer which lines the embryo-sac arrange themselves with
a certain regularity, becoming distributed at equal dis-
tances on the inside of the wall of the embryo-sac. As
a cell is fonned around eacli of these nuclei, and on all
simultaneously, the embryo-sac becomes lined with a
layer of cells, the first of the endosperm. On the inside
of this a second layer of cells is soon deposited in a similar
manner ; tliis is followed by a third, and so on. Leaving
out of view the lamellar rcpctition, this process of cell-
formation clothing the wall reminds us very much of that
examined under n. 2 ; the cxlmustion of the contents of
the embryo-sac (i. e. the mothcr-ccll) occurring with the
formation of the last, innermost endosperm-cells, is related
to d. 1.

When we consider the wliole of the phenomena of
cell-formation in the embryo-sac connectedly, we behold
the case, unique in its kind, of a mother-cell in which
different kinds of daughter-cells are produced at different
periods. None of these daughtcr-cells belong any more
to the tissues of the mother-plant ; all, as cells originating
free, are in a certain sense reproductive cells, new indi-
viduals; but of the manysisters, only one, the first-born,
is ordinarily destined to become perfectly developed,
while the majority of the otliers are compelled, in their
earliest childhood, to perform nursing-service to the
cliosen one. The difference of the cells fonned in the
embryo-sac may indecd bc compared with the occurrence
of bimorphous, partly fertile, partly sterile gonidia in
the Algai; the parenchymatous conjunction of the ori-
ginally free endospenn-cells reminds us of the regulär
combination of the previously free gonidia of Hydro •
dictyon and Pediastrum ,

exaltata ;) also Hofmeister, 1. c., t. xii, f. 25 {Pohjgonum orientale;') ancl
t. xiii, f. 21, (. Helianthus annuus.)

* L. c., p. 30, t. xi, f. 25, 26, 29, {Sorghum bicolor.)

REJUVENESCENCE IN NATURE.

281

Nägeli* treats, in the section on free cellformation, the
phenomena of abnormal cell-formation, which are observed
in decaying contents of old cells. The mode of formation
of fliese abnormal cells certainly agrees most of all with
the cases last discussed, but has the pecnliarity that the
new structures escaping the solution and decay of the
rest of the cell-contents are incapable of development, or
only of abnormal development, descending into diseased
structures or pseudo-organisms. The character of these
abnormal cells is most varied and changeable ; especially
remarkable is the occurrence of globular, resting, spore-
like cells ( e . g. in old Closteria), f as also the appearance
of active, Infusorioid structures, which occur not unfre-
quently in the interior of decaying cells of green fresh-
water Algte (<?. g. CEdogonium, Spirogyra),\ and are dis-
tinguished from normal swarming-cells by their irregulär
form, varying size, slower motion, and mostly brownish-
yellow contents, succeeded by hyaline, finely granulär
mucilage. In Spluerojjlea I liave often seen such pseudo-
gonidia formed in the same cells with normal spores.
Abnormal structures of this kind have doubtless often
been confounded with the normal reproductive cells of
the Algse. The future will certainly unfold many in-
teresting phenomena in this hitherto little-worked Held.

In the preceding summary of the modifications in
which the process of Rejuvenescence of cells advances to
new constructions, we have seen division of the cells
occur as a very ordinary accompaniment of the recon-
struction, and this in manifold ways. With these pro-

* ‘ Zeitschrift,’ 1847, p. 24, t. iii, f. 1 — 3 ( Bryopsis Balbisianum.) (Ray
Society’s traust, 1849, p. 98, t. ii, f. 1— 3.— A. H.)

t Meyen, * Pflanzen-phys.,’ iii, t. 10, f. 24, (also figured by Rocke,
‘ Physiol. Studien,’ pl. iii, f. 12. — A. Ii.)

+ (See Pringshelm, on Spirogyra, Tränst in 1 Annals of Nat. Hist.,’ 2d
series, vol. xi, p. 210. Also consult on this point Itzigsohn, ‘ Bot. Zeit.,’
1853.— A. H.)

282

THE PHENOMENON OF

cesses of division are connected, in tke first place, tlie
development of the tissue with its varieties, even the
development of the contrasts of the external organs (in
the higher plants), and, lastly, the multiplication of the
individuals, both through vegetative increase, and through
true reproduction. The formation of free reproductive
cells, may also be termed division, in so far tliat their origin
depends upon a parting of the contents of the mother-
cell. In Opposition to this effort towards division and
Separation, towards the development of multiplicity, both
from the repetition of the like and theshaping out of the
various vital tendencies in structures of many kinds — the
plant manifests, on the other hand, in certain periods of
conclusion and transition, an effort toward reunion of the
divided, either by gathering np and combining the
homogeneous, or bringing together opposites. In the
higher divisions of the vegetable kingdom we meet with
this phenomenon in many forms. The intimate com-
bination of the organs at the higher steps of the meta-
morphosis, the fusion of parts in the individual whorls of
the fiower, adherence even of entire whorls to each other,*
but in particular the biending of the carpels into closed
germens, exhibit the effort at reunion of the separated in
the inorphological field, as the phenomena of fecundation
do in the physiological. But even in the lowest plants,
which do not possess the variety of organs and the con-
trast of sexes, whose whole cycle of vegetative life is
limited to the development of a single cell, or a series of
similar cells, we find acts of this uniting and collecting
vital tendency. Among the principal of these is the
phenomenon occurring in the Algse and Fungi, to which
the name of conjugation of the cells has been applied ; a
phenomenon which always occurs at the close of the vegeta-
tive development, ordinarily at the termination of a series
of unicellular generations produced by dividing-increase,
and is for the purpose of forming, directly or indirectly,

* Wkence arise the perigynous aud epigyuous insertions.

REJUVKNESCENCE IN NATURE.

283

reproductive cells, the transition-cells to a new vegetative
cycle.* * * § In the preceding summary of the conditions of
cell-formation, I have purposely avoided mixing up those
cansed by conjugation ; as the opposite of all kinds of
cell-formation combined with division, they deserve a
separate examination, through which, from the insuffi-
ciency of most of the descriptions of the cases belonging
here, I purpose, at the same time, an attempt at placing
the subject in its proper light (Orientirungs-versuch), to
guide in future investigations. In the following collo-
cation we restrict the idea of conjugation to those cases
in which: 1, two previously really separate cells unite;f
2, the combination takes place by actual anastomosis, not
by mere application together of tbe cell-walls ; | 3, an
immediatd'intermixture of formative cell-contents occurs.§
Thus, in true conjugation, two previously separate cells are
united in such a manner that in the combined state they
can only be regarded as one cell, the two halves of which
sometimes remain distinguisliable, connected by a narrow
isthmus or by a canal (trabecula), but sometimes coalesce
so completely that the earlier boundaries entirely disap-
pear. In such Union, either all parts of the combining
cells (membrane and contents) enter into conjugation, or
the cell-membrane, and then either the whole or only the
outer, remains out of the combination, bursting so as to
let the inner membrane or merely the contents (with the
primordial utricle) conjugate. In this case it may happen
that the contents divide within the cell-membrane shortly
before the conjugation, so that two cells are fonned

* See above, p. 132. (Diatomaccfc) ; pp. 133 — 135, (Desmidiacese,
Zygnemacero.)

f This excludes the phenomena in the formation of the spores of Mclosira,
(Eclor/onium, and Bulbocheete, subseijuently to be examined more closely, which
liave been mixed up with conjugation.

\ This excludes the mere application of other cells upon the mother-cell
of the spores, such as occurs in Coleochcete and Saprolegnia, as also the
union of the pollen-tube with the embryo-sac.

§ This excludes the anastomosis of the colourless cells of the leaves of
Sphagnum, Dicranum r/laucum, and Cfcrtain other white-leavcd Mosscs, as
also the union oflong tubulär spiral-fibre-cells to form vessels.

284

TUE PPIEN0MEN0N OF

through double conjugation of the contents of two
dehiscing mother-cells, which extrude tlieir contents.
The conjugation-cell fonned in either of these ways, is
either itself a reproductive-cell, or the latter is formed by’
a further metamorphosis of the combined contents within
the conjugation-cell, and this mostly takes place either in
one of the halves of this, or in the connecting piece
between the halves ; it is mostly a resting spore, more
rarely an active gonidium, rarest of all the combined
contents divide into a number of cells in tlieir transforma-
tion for the purpose of fructification. These, and other
less essential differences, produce the multiformity of
cases in which the phenomenon of conjugation presents
itself, especially in certain families of the Algae, while as
yet it has only bccn observed in one genus of the Fungi,
licre, however, in a modification deviating from all the
rest. In the following summary I shall endeavour,
as far as possible, to place all the known examples.

a. Conjugation of similar, cells. — The uniting cells
may be either free and isolated, as in most Diatomacese
and Desmidiaceae, or they may be links of a many-celled
filament, as in the Zygnemacese. In isolated cells the
Union mostly takes place by the sides of the cells, either
by parallel or by crossed approximation {copulatio
lateralis par allela, s. decussata ) ; very rarely by the apices
of the cells ( copulatio apicalis). In the jointed (many-
celled) filaments the union takes place either by each two
successive cells of the same filament anastomosing with
tlieir adjacent ends by lateral processes, which we will call
chain-union {copulatio catenativa) ; or by the links of two
different filaments (or, as may equally happen, different
parts of the same filament overlying through bending),
uniting by tlieir sides : yoke-union {copulatio conjuyativa ),
in which case the cells may be either bent like a knee in
Order to reach each other {conjuyatio genuflexa), or be
united without bending, by processes growing out to
meet each other and coalescing into a transverse canal :
laddev-likc union {copulatio scalaris). lhese distinctions,

REJUVENESCENCE IN NATURE. 285

however, are less essential than those on which the fol-
lowing subdivisions are founded :

1. Tlie conjugating cells unite entirely ( with membrane
and contents ), and, completely coalescing without tlirowing
off a membrane, form a seed-cell [spore) . — The spore
originates here as the direct result of conjugation, not
subsequently through a further transformation of the
contents after the conjugation ; the conjugation-cell is
itself the seed-cell, and does not produce the latter as a
new cell within itself. Here refers Pcilmoglcea , the
remarkable, of its kind unique,* * * § conjugation of which
was only represented in its coinmencement by Kützing,f
described in its further course by Thwaites, but, since he
assumed an absorption of the cell-membrane of the com-
bining cells, mistaken by liim exactly in its inost essential
peculiarity, f I have mentioned my own observations on
the conjugation of Palmoglcea above ; § the minute
description of the process, with remarks on the species in
which the observations were made, will follow in the
description of the plates.

2. The conjugating cells, leaving behänd the outer
membrane, unite directly to form a reproductive cell. —
The occurrence of this case is not improbable, but has
not yet been made out with certainty.

3. The conjugating -cells combine merely their contents
[founded by the primordial utricles), to form tlie repro-
ductive cell ; the dehiscent cell-membrane is deserted. —
The conjugation of many Diatomacese || very probably
belongs here. The mode in which, according to the

* Similar cases occur in tlie animal kingdom, in the Infusoria. See
Kolliker on Actinophrys Sol, in Siebold and Kölliker’s ‘Zeitschrift,’ 1849,
b. i, p. 207, (Transl. in ‘Quarterly Journal of Microscopic Science,’ vol. i,
p. 98, et seq.) The forms figured as Actinophrys difformis, by Ehrenberg,
(‘ Infusionsthierchen,’ t. xxxi, f. 8,) doubtless represent conjugating states
of Actinophrys Sol.

t Assuming tliat bis Palmoglcea Meneghinii, (‘ Tab. Pliycol.,’ 24, iii,)
actually belongs to this genus, and not to Cylindrocystis.

% ‘Ännals of Nat. Ilistory,’ 1849, 2d series, vol. iii, p. 243, t. yiii, f. c ,
(as Coccochloris Prebissonii.)

§ See pp. 135, 202, and pl. i, figs. 1 — 28, pl. ii, figs. 1 — 14. || Sec p. 132.

286

THE PHENOMENON OF

descriptions of Thwaites,* * * § the cell-contents emerge from
the Splitting siliceous cell-coats, and, speedily uniting
between the emptied sliells of the mother-cells, acquire
the globular form, renders the assumption tolerably safe,
that the masses of contents unite here. Nomembranous
canal formed by an internal cell-membrane, inside which
the masses of contents unite, seems to exist here. Since
the conjugating individuals are always held together by
an abundant gelatinous secretion appearing at this time,
it is not difficult to conceive the persistence of the pair
of cells in their approximated position, even without the
formation of membranous tubes of conjunction. The
reproductive cells of the Diatomaceae formed through
conjugation have no seed-sleep, but, although not active,
pass directly, in the manner of gonidia, into vegetative
development.

a. The contents of the tim cells unite without previous
division ; — in this way one gonidium is formed by two
mother-individuals. Thus in Himantidium . f

h. The contents divide in hoth cells hefore the union
into two masses ; — in this casetwo gonidia are formed by
two mother-cells through double conjugation. According
to Tlnvaites’s representation, the division of the contents
preceding conjugation is transverse in Eunotia, Crossing
the direetion of division in vegetative increase.

a. The new individuals developed from the two
gonidia, soon surpassing the mother-cells in size, cross
the shells of the mother-cells. Thus in Eunotia tur-
gida.% • '*

ß. They take a position parallel to the shells of the
mother-cells. Thus in Cocconema ,§ Gomphonema, || and
Schizonema.

4. The conjugating -cells unite with participation of

* ‘ Annals of Nat. History,’ 1847, vol. xx, pp. 9, 343; 1848, ser. 2,

vol. i, p. 161. _ _ „

f Tmvaites, 1. c., 1847, vol. xx, p. 22, f. a, 1 7.

% IbicL, t. iv.

§ IbicL, t, xxii, f. c, 1 — 3.

|| Ibid., t. xxii, f. B, 1 — 5.

RF.JUVENESCENCE IN NATURE.

287

the eocternal membrane ; the reproductive-cell is formed
throuyh contraction of the contents clothed by the internal
cell-membrane. — The formation of the reproductive-cell
(in the cases to be mentioned, of a spore) is consequently
here not a direct result of the conjugation, but it is
formed subsequently in the interior of the conjugation-
cell, in the strongly expanded isthmus of this. The deli-
cate internal membrane, with the contents enclosed by it,
drawing itself out of the (on account of the thickness of
the outer membrane, rigid) extremities of the double-
cell, forms a seed-cell, at first cruciate-four-lobed, then
bluntly quadrangular, and finally globular, clothed by
a many-layered thickened membrane, within the persistent
four-liorned conjugation -cell. From Ralfs’s representation
this is most probably the way in which the process is to
be understood in Cylindrocystis JBrebissonii, Menegh.
(ex. p.)* The participation of the outer membrane in
the conjugation is beyond doubt ; this is the principal
character distinguishing the genus Cylindrocystis from
Peniunt. The resemblance of the quadrangular internal
cell to that of Tetmemorus, in which this is undoubtedly
formed of a delicate cell-membrane, testifies in favour of
the existence of the latter in this case also. From the
cruciate or quadrangular shape of the spore, it may be
conjectured that the conjugation of genus Stauroceras, f
likewise belonging to the group of Closterina, as also
that of the Zygnemaceous genus Staurocarpus,\ Flassall
C Staurospermum , Kg.), belong here.

5. The conjuyatiny cells unite with participation of the
outer membrane ; the reproductive-cell is formed out of
the mere contents , as a new cell , inside the mother-cell.
—This case (occurring in the majority of the Zygne-
macese) differs from the preceding by the non-participation

* Penium ( OylincLrocydu ) Brebissonii, Ralfs, ‘British Desmidiea:,’ p. 153,
t. xxv, f. 6.

f Ehrenberg, * Infusionsth.,’ tab. vi, f. 94. Ralfs, 1. c., t. xxx, f. 4,
Stauroceras subulata, K. ;) ibid., f. 3, (St. Acm, Iv. ;) f. 5, (St. acutum , Breb.)

+ Hassall, ‘British Freshwater Algcc/ t. 4 *7 — 49.

288

THE PHENOMENON OF

of the inmost lamella of tlie cell-membrane in the formä-
tion of the reproductive cell.

a. With ladder-like (scalariform) yoke-conjuga tion .

a. The spore in the connecting canal or middle piece
of the double cell. In Zygogonium. * * * §

ß. The spore in one half of the double cell (in the
cavity of one of the two conjugating raother-cells).
Ordinarily the case in Spirogyraf and Zygnema.%

y. A spore in each half. This case occurs only as
abnormal in Spirogyra, and appears to depend upon an
incomplete carrying through of the conjugation, the
union-processes Corning into contact., but not anas-
tomosing.§

b. With knee-sliaped ( geniculate ) yoke-conjugation.

a. The spore in the uniting canal or middle piece. In
Mesocarpus. ||

ß. The spore (or the gonidium) in one of the halves of
the double-ccll. Here belong Sirogonium ,^[ with a spore
fornied exactly as in Spirogyra, and the genus Mougeoiia **
still enigmatical in its mode of reproduction, probably
possessing an active gonidium, leaving the mother-cell
directly after its formation.

c. Chainlike ( catenate ) union of the cells of the scime
ßlament.

a. The spore in the lateral connecting-canal of the
conjugated-cells. This case is not yet known, but it is

* Vauchcr, ‘Histoire des Confcrves,’ t. vii, f. 3 — 4; Hassall, 1. c.,
t 39.

f Yauclier, 1. c., t. iv and v; Hassall, 1. c., t. 18, 25, and 27—32.

+ Yaucher, 1. c., t. vi, f. 4 ; t. viii, f. 1, 2 ; Hassall, 1. c., t. 38.

§ Yide Kützing, ‘Pliyc. General,’ t. 15, f. 1, 3, 4, 6 (of Spirogyra
quinina.

I Hassall, 1. c., t. 42 — 45.

Hassall, 1. c., t. 26.

** Hassall, (1. c., p. 172,) indeed, asserts tliat Mougeotia is propagated by
zoospores, but gives no further information regarding tjieir formation.
Yaucher (1. c., p. 79, t. viii) formed out of Mougeotia the section “ conjugees a
tubes intörieurs,” and describes the emergence of already elongateci many-
celled young filaments from the old cells, a plienomenon wliich may be
explained as accidental development of gonidia remaining in the mother-
cell.

REJUVENESCENCE IN NATURE.

289

conceivable that Hassall’ s stränge Mesocar pus notabilis* * * §
belongs here ; tliis would require the assumption, that
the uniting canal, becoming iilled with the contents of
the two conjugated-cells, pushed aside completely the
septum between them.

ß. The spore in one half of the double-cell (in the
cavity of one of the mother-cells). This is the case in
Hassall’s second division of the Spirogyra ,f which
Kützing has distingnished as a peculiar genus, under
the name of lihynchonema. j

d. Lateral, parallel Union of isolated cells. — Here
belongs theconjugation of Closterium Lunula (see p. 140),
in which, according to Morren’s express Statement, §
three different membranes take part in the formation of
the canal of union, an inner and an outer cell-membrane,
and a membrane (the primordial utricle) immediately
enclosing the green mass. The globular reproductive-
cell formed in the connecting canal, is an active gonidium,
which begins to revolve even while within the canal, and
soon breaks through the gelatinously swollen membrane
of the latter. Very often two approximated individuals
divide again and conjugate before they have become
completely separated : whence result conjugated double-
pairs. || According to Ralfs’ description of the conju-
gation of Penium Jenneri, it resembles that of CI. Lumda,
a large globular spore being formed in the interior of a
connecting canal, narrow at the points of issue, like
that of Mesocarpus .^[

* Hassall, 1. c., t. 46.

t Hassall, 1. c., p. 152, t. 33 and 34; Nägeli, ‘Algensysteme,’ p. 151,
t. iii, f. 22 — 25.

+ ‘ Spec. Alg.,’ n. 443. The genus Rhynchonema, although based on a
very remarkable cnaracter, is scarcely natural, since botli kinds of conjuga-
tion sometimes occur in one and the same species. I have observed this
especially in Spirogyru Weben, in which, however, the chain-union is more
common than the yoke-union.

§ ‘ M6m. sur les Closteries,’ ‘ Ann. des Sc. nat.,’ 2 ser., v, 325, t. 9
(1836.) (See also Smith, on Closterium, ‘ Annals of Nat. History,’ sec. ser.
vol. v, p. 8, t. i. — A. H.)

|| Morren, 1. c., t. 9, f. 22, 23, (Smith, 1. c.)

1 Ralfs, 1. c., p. 153, t. 33, f. 2.

19

290

THE PI1EN0MEN0N OF

c. Conjugation of branched filiform cells by club-shapcd
branches , whicli unite at their points. — The only known
example is the remarkable genus of Mildevv Fungi
Syzygites, discovered and figured witli a master’ s hand
by Ehrenberg.* Erect, dichotomously branched, inar-
ticulate flocci, therefore unicellular filamentous little
plants, grow side by side in dense tufts. The uppermost
branches of the forks curve, like a pair of tongs, towards
each other, and send out (usually on the inner side of the
arms) clavate or pear-shaped branchlets. These fruit-
clubs, sometimes the opposite ones of the same fork,
sometimes tliosc of different forks intermingled through
the social growth, unite by their apices. Ehrenberg
could not detect an actual anastomosis with certainty,
but it most probablv does occur. In the middle of the
spindle-shaped conjugation -body thus produced, the
granulär oontents of the filaments ascend in a current
from both sides, and collect into a globular mass, whicli
becomes intimately combined with the membrane of the
middle-piece of the spindle, and shut off from the lateral
pieces by septa, and final ly becomes free between the
two lateral portions, without these being torn. The
globular body becomes brown, and at length black,
during its development, and is a thick-walled cell, in
whicli, if we may put faith in Corda’s figure, free
spores are formed, imbedded in a soft amorphous
mass.f

6. The conjugaling cells, after dehiscence of the outer
membrane, unite through the inner ; the reproductive cell
is formed out of the mere contents, as a neio cell inside
the conjugation- cell. — This is undoubtedly the condition
in the majority of Desmidiacem. The union almost
always takes place between isolated cells in this family ;
even in the genera with the cells connected into filaments

P

* ‘ Verliandl. der Gesellsch. näturförsch. Ereunde zu Berlin,’ .1 baud.,
t Porcia,11'1 EraoEtflora Europäischer Schimmelbildungeu,’ (1839,) p. 49,

t. 23.

11EJUVENESCENCE IN NATURE.

291

or ribands {Hyalotkecci, Didymoprium, Isthmosira ), the
conjugation does not commence until the filaments have
broken up into their individual links. In Bambusina
alone, according to Ralfs, occurs the case of isolated cells
conjugating with others still constituting links of con-
tinuous filaments, and thus becoming attached, like
parasites, upon the filaments. The dehiscence of the
external cell-membrane is especially evident in Tetme-
morus and most Closteria ; it always takes place in a
transverse direction, in the middle between two halves.
While the dehiscing outer membrane opens more or less
widely on one side (like the dehiscing cells of Qddogonium),
the delicate internal membrane protrudes as a tubulär
procesSjto unite with the corresponding process of the other
cell. If, at the saine time, the internal cell-membrane
remains connected with the outer cell-wall, the halves of
the dehiscent cell-membrane mostly remain approximated
together and connected with the uniting canal and the
spore, which usually fills this up (e. g. in Clostenum
acerosum , lineatum , &c.) ; but if the loosened internal
cell-membrane gradually extricates itself from the outer,
the halves of the latter become separated and are readily
thrown off {e. g. in Tetmemorus).

a. Conjugation in a parallel position. — This is peculiar
to the group of Closterina. In the species with curved
cells the union takes place (with rare exceptions) by the
convex side, so that the conjugated specimens have their
points diverging.

a. The halves of the dehiscent cells separate from each
other all round, the internal cell-membrane entering into
conjugation gradually emerging wliolly or almost entirely.
The spore formed from the contents lies loose in the
delicate conjugation -cell. This is the case most evidently
in Tetmemorus ;* according to Ralfs figures, Docidium, f
and a section of the Closteria having longitudinally

292

THE PHENOMENON OF

striate and truncated ends,* * * § seem to exhibit a similar
behaviour.

ß. The halves of the dehiscent cell only separate a
little on the side turned towards the other individual, at
which the internal membrane emerges, while they remain
connected on the outer side ; the internal membrane
remains as an internal Investment in the outer; the
spore mostly fills the uniting canal so completely, and is
in such close contact with its vvalls, that the latter is
scarcely distinguishable. This is the condition in jPeniumf
(with the exception of the species mentioned previously),
and the unstriped Closteria\ (with the exception of- the
above-mentioned CI. Lunula).

Closterium lineatum\ also belongs here, but with the
peculiarity, known only in it, that two spores are formed
between two individuals. As I have had an opportunity
of observing tlie process of conjugation minutely in this
very species, || I am able to explain the mode of origin of
the really double spore (not two-lobed, as Ralfs terms it).
The very much clongated, only slightly curved specimens
of dost. lineatum, lie close together in pairs before
conjugation, sometimes with both the convex sides in con-
tact, sometimes with the convex side of one touching the
concave side of the other. The cell-membrane dehisces
transversely, either siinultancously in both, or in one
earlier than the other, in the middle of the cell, previously
marked outside by an annular line, and inside by an
interruption of the grecn contents, but this takes place
in such a manner that the two halves only separate a
little on the side turned towards the other individual,
remaining connected on the opposite side, so that the

* Ralfs, 1. c., t. 29, f. 2, (Closterium striolatum) ; fig. G, 7, (Closterium
juncidum.)

f Ibid., t. 25, f. 1 and 5, Penium margaritaccum and truncatum .)

+ Ibid., t. 27, f. 2, (Clost. acerosum;) t. 28, f. 4, (Closl. Leibleinii.)

§ Ehrenberg, ‘ Infnsionstb.,’ t. G, f. viii, 4.) Ralfs, 1. c., p. 174, t. 30, f. 1.

|| ln the middle of May, 1848, in specimens from the peat-holes of the
Mooswald, near Freiburg, especially rieh in Ecsmidiaceae.

The two pieces are mostly of unequal length.

REJUVENESCENCE IN NATURE.

293

cell becomes broken geniculately, tbough only at a very
obtuse angle. The opening produced by the slight
dehiscence of the outer cell-membrane, forming a cross-
slit in one side, is immediately occupied by two thickened
projections of an internal cell-membrane issuing out.
These two thickened processes are the ends of two deli-
cate-walled daughter-cells, meeting in the centre of the
m other- cell, and which are probably formed by division
of the contents of the mother-cell very shortly before the
beginning of the conjugation. Since only these internal
cells enter into the conjugation, we have here, not, as
appears at first, a simple conjugation of two cells, but,
strictly speaking, a conjugation of two pairs of cells ;
since, moreover, the two issuing processes, which unite
with the two coming to meet them from the other side,
are the ends of the two internal cells, Closterium lineatum
affords the rare example of a cojoulatio apicalis. The
individuals destined to conjugation lying near together,
the thickened projections do not grow out into long
processes, but apply themselves, in the form of everted
lips, directly upon the corresponding parts of the other
individual, or, if this has not yet pushed out its thickened
processes, upon its closed external cell-wall. This pro-
cess of the commencement of conjugation cannot be
described better than 'by comparing it to the contact of
four thickened firmly appressed lips in a kiss mouth to
mouth. The thickened projections are originally trans-
parent and ahnost colourless, since only a few green
granules can be observed in them, often in distinctly circu-
lating motion, entering at the back and retiring from the
front into the interior of the cell; the green contents
soon follow, however, in abundant quantity. The four
protuberances next become so densely filled with green
matter and pressed so closely together, that the coupling
growth and anastomosis taking place during this crowding
up cannot readily be traced, but it is clearly sliown by
the result. Sornetimes the delicate membrane of the
protuberance bursts under the pressure of the contents.

294

THE PHENOMENON OF

so that the latter become diffused, or form an irregulär
accumulation between the two mother-individuals, which
of course frustrates the formation of the spores. In
normal development the whole mass of green contents
enters in a short time into the two connecting canals,
which swell up from the middle, where they are in con-
tact, out, in opposite directions, into obovate or almost
globular sacs, which wedge themselves in closely between
the four legs or horns of the conjugated individuals. In
each of these sacs the contents become balled into a
globe, which becomes clothed with a cell-iueinbrane, at
first delicate and smooth, afterwards thick and granulated.
In tliis way, therefore, two spores are formed, completely
separate in their origin, which so closely fill up the deli-
cate sac-like canals of Union in which they are formed,
that as they lie between the mother-individuals, they
appear like free globales, but are persistcntly connected
with the mother-cells by the empty and colourless lateral
parts of the two closely approximated uniting-canals,
which extend into the valve-like openings of two empty
shells. These connecting pieces, formed from the inner
membrane, are readily distinguislied, by their want of
colour, from the outer membrane or shell, which appears
straw-coloured after the contents are emptied out. A
not unfrecpient abnormity affords a further proof of the
origin of the two spores through conjugation of opposite,
completely distinct pairs of cells ; tliis is the occurrence
of only one spore between two mother-individuals. In
this case only two corresponding halves (or horns) of the
mother-individuals become emptied, while the two others
remain densely filled with green contents, which, in spite
of the dehiscence of the outer cell-membrane, cannot flow
out.

b, Conjugation in crossed ( decussate ) position. — This
occurs in the entire group of forms allied to JEuaslrum ,
and also in many genera formerly United with Des-

midium.

a. The halves of the dehiscent cells separate by an

RE J U VEN ESCEN CE IN NATURE.

295

annular slit, the protruded internal membrane entering
into the conjugation becomes very strongly developed.
The spores become free by the disappearance of the
enlarged saccate conjugation-cell ; this also sets the
halves of the old cell-membrane free, from which the
internal membrane does not seem to be drawn out as in
Tetmemorus. This case occurs in Euastrum* * * § and the
genera intimately allied to, and difficultly separable from
it, Micrasterias,\ Cosmarium,\ Xanihidium, § Staurastrum
(. Phycastruvi , K.)|| The complete Separation of the
halves of the motlier-cell membrane does not, however,
seem to be constant, for Ralfs gives ftgures of the same
genera, and even of the same species, as those above
cited, which exhibit halves connected together at one
side.^[

ß. The halves of the dehiscent cells separate only at
one side, in Order to emit the connecting canal formed
out of the internal membrane, not expanded into a.sac;
thev do not become detached. The spores are formed
either in the middle of the connecting canal (as in Hya-
lotheca** Bambusina,\\ and Isthnosira ( Sp/usrozosma ,
Ralfs), || or in one of the halves, in a manner similar to
that we have seen in Zyynema and most of the Spirogyrcc ,
a case which is only known with certainty in Bidymo-
jprium §§ among the Desmidiaceae, but perhaps occurs also
in the genus Desmidium. || |

* Ralfs, 1. c., t. 12, ( Euastr . oblongum ;) t. 14, f. 5, {JE. pectinatum,) &c.

f ibid., t. 6, f. 1, (Micrasterias denliculata, with the mace-like spores
beset with forked spines ; the conjugation itself is not represented.)

X Ibid., t. 16, i. i, ( Cosmur . Botrytis-) f. 2. (C. margaritiferum) &c.;
Nägeli has also described the conjugation in a species of this genus, his
C. rupestre, (1. c., p. 118, t. vii, f. 6.)

§ Ibid., t. 18, ( Xanth . urmatum.)

|| Ibid., t. 20, f. 5, (St. dejectum ;) t. 21, f. 5, (St. orbiculare ;) t. 22, f. 3,
(St. hirsutum ;) f. 9, (St. polymorphum ;) t. 23, f. 9, (St. brachiatum,) &c.

E. g., of Cosmarium margaritiferum , t. 33, f. 6 ; Cosm. Broomei, t. 33,
f. 7 ; Arthrodesmus Incus, t. 20, f. 4.

** Ilalfs, 1. c., p. 53, t. 1.

|t Ibid., p. 59, t. 3, (as Didymoprium Borreri.)

XX Ibid., p. 67, t. 6, f. 2 (I. excavata;) t. 32, f. 2, (I. vertebrata.)

H Ibid., p. 55, t. 2, (Didym. Grevillii.)

II II Ibid., t. 4, where Ralfs represents spore-like globules in the interior

2 90

THE PIIENOMENON OF

7. The conjugation taJces place witli participation of
the entire membrane ; inside the double-cell thereby formed
the internal membrane contracts into narrower limits,
aioay from the toall of the expanded isthmus, forming a
cruciform or quadrangular internal cell ; inside tlie latter
the contents contract again to form finally a globular
spore — This case is required by the preceding as con-
clusion of the series. If we liave placed Staurocarpus
properly under 4, and if it be correct that, as Ralfs*
remarks, in passing, in the description of the conjugation
of Tetmemorus, there exists a species of Staurocarpus in
which a globular spore is formed inside the quadrangular
cell by further contraction of the contents, this case does
really occur.

b. Conjugation of dissimilar cells. — I know of
no othcr eases to place in this entire second section, but
the conjugation of Vaucheria asserted by Nägeli,f which
case, liowever, although I cannot but confirm Nägeli’s
observations, is not yet placed bcyond doubt in my
mind. A certain reciprocal action of the slender liook-
shapcd sterile branchlets or horns as they are called
(the anthers of Yaucher), and the tliick inflated lateral
branchlets which produce the spore in the extremity,
cannot well be denied. Even Yaucher j described the
application of the former upon the latter, and figured it.
in Vaucheria sessilis ; Hassall § observed that in those
species in which the spore-forming branchlets emerge in
considerable n umbers from the base of a simple horn, as
in Vaucheria geminata, the spore-forming branchlets,
vice versa , apply themselves upon the horn, and subse-
quently remove again and curve backwards. According
to Niigeli’s and my own observations on Vaucheria

of the cells of au imconjugated piece of Desmidium Swartzii. Miglit anotlier
filameut have been connected witli this, and again detachcd after being
emptied ?

* L. c., p. 146.

f See ‘ Algcnsyst.,’ p. 175, t. iv., f. 21, 22.

X ‘Hist, des Conferves d’Eau Donce,’ (1803,) p. 17, t. ii, f. 7.

§ Hassall, 1. c., p. 49, t. 3, f. 1.

REJUVENESCENCE IN NATURE.

297

sessilis, after the Separation of the horn from the spore,
the former appears open at the point, and a considerable
space, doubtless shut off as a separate end-cell before the
Separation, empty ; the spore is at this time likewise
surmounted by a more or less distinct tube, empty and
open at the summit, which undoubtedly is the open end
of the mother-cell of the spore. The open end of the
emptied end-cell of the horn on one side, the open end
of the mother-cell of the spore on the other, together
with the fact that the two were previously connected,
certainly render it very probable that this connection is
a real conjugation, that, therefore, the contents of the end-
cell of the horn are united with those of the mother-cell of
the spore to form the spore itself. The application of the
horn upon the spore-bearing branch ought then to take
place before the formation of the spore, on which point
my observations are deficient, but which is in agreement
with Nägeli, figure 21.'* However, on the one liand, the
circumstance is puzzling that many species seem to pos-
sess no trace of the said open tube surmounting the
spore, f while other species exhibit open tubes in the
spore-branchlets with no horns corresponding to them,
as, for instance, V. poZysperma, Hassall, :j: with very
numerous, linearly arranged spores, but only very few

* See, on this point, Karsten on ‘ Conferva fontinalis, L.,’ in the
1 Botanische Zeitung,’ 1852, p. 89, et seq., pl. 1, wherein he describes the
conjugation in all its stages. — A. H.

f Thus, for example, in Vaucheria terrestris and hamata, in which, at the
same time, in spite of the stränge position of the spore on the back of the
horn, an union of the inrolled point of the horn with the spore does occur,
as is represented very beautifullv, and even with emptying of the end-
cell of tue horn, by Thuret, (‘Sur les ürg. Locomot. des Spores des
Algues,’ ‘ Ann. des Sc. nat.,’ 2d ser., vol. xix, t. 15, f. 49, (1843,) in a form
doubtless belonging to V. hamata. In V. geminata the little tube above the
spore is likewise wanting, but Nägeli has seen a scar on the summit of the
spore, which indicates the previous union with the horn, and indeed, accord-
iug to Hassall’s observations, not with the point but with the side of the
horn. The form of the horn in V. cruciata , (Vauch., 1. c., t. ii, f. 6,) nearly
allied to V . geminata, is interesting, since two little side horns issue from
the principal horn, from tlieir position cvidently destincd to union with the
two spores.

1 L. c., t. 4, f. ß. I have observed this species also uear Trciburg.

298

TUE PHENOMENON OF

liorns, which, moreover, as in Vauch. sessiZis, exhibit an
empty open end-cell at the period of maturation of the
spores. The genus Vaucheria, vvhich has already so muck
occupied naturalists, still requires, therefore, further and
more minute investigations in reference to the formation
of its reproductive Organs. In conclusion, I will mention
certain other cases which bear some resemblance to the
phenomena of conjugation, and have beeil, in fact, really
regarded as such. In Saprolegnia, which exhibits so
much likeness to Vaucheria in morphological respects,
we find a structure similar to the liorns of Vaucheria.
At the period of the formation of the resting-spores,
between the lateral branches swelling up into pear-shaped
spore-cases, appear frequently, but not constantly, slender
vermiform branchlets, which, wlien they reach the spore-
cases, apply themselves firmly upon these, and indeed
sometimes twine round them in irregulär coils ; no actual
anastomosis takes place however. Coleoclucte pulvinata
(see page 1 Gl) exhibits a phenomenon which may be
compared with tliis. The sporangium of this species
originates by the expansion of the last or last but one
cell of a filament, and is, in itself, a simple cell, which,
however, acquires a most complete cellular envelope
through the close application upon it of cellular branch-
lets, partly arising from the cell immediately preceding it,
partly reach over like bridges from branches situated lower
down or neighbouring filaments. The direction, differing
from the ordinary erect growth, in which the branches
combining with the sporangium come in from all sides,
sometimes horizontally, and sometimes even descending,
shows, altliough there may not be so intimate a Connec-
tion and so direct a co-operation for the formation of the
spore as in conjugation, that there is, nevcrtheless, here,
a similar reciprocity of attraction and seeking-out of the
parts, as well as a material assistance in the spore-
formation, through the connection of the mother-cell of the
spore with the numerous smaller cells forming the enve-
lope, doubtless effected through the process of endosmose.

REJUVENESCENCE IN NATURE.

299

Distant as the physiological importance of these pheno-
mena öf application just described Stands, from the appli-
cation of the pollen-tube on the embryo-sac, and through
the medium of this, on the germinal vesicle, connected
with the fertihsation of the Phanerogamia, the resem-
blance between the processes of the two phenomena is
unmistakeable.

Some of the Diatomaceae afford another case, to be
placed here as it were in an appendix, which perhaps
might be regarded as an instance of arrested conjugation.
While I have seen in many genera of this family an
actual conjugation of completely separate cells (p. 286),
in the group of the Melosirece the large reproductive-cell
which commences the new series of generations (the
sporangium,* as it is termed), is formed out of the Con-
tents of a single grown-out cell, the shell or membrane of
which, dividing in the middle, separates to allow space
for the expansion of the newly-formed, more vigorous
primary-cell. Thwaites,f who describes this process in
several species, thinks that it may be brought into
agreement with the conjugation occurring in other
groups of the same family, by assuming the division of
the contents of the mother-cell into two portions pre-
viously to the formation of the new cell, these portions,
instead of developing into separate cells, as in the vege-
tative increase by division, combining together again im-
mediately in Order to produce the reproductive-cell.
Although this hypothesis is not yet substantiated by
direct observation, it deserves attention, since it opens
a common point of view for the phenomena of reproduc-

* See ]). 141, note.

t See Thwaitcs, ‘ Further Obs. on Diatomacem,’ ‘Annals of Nat. Ilist.,*
sec. ser., vol. i, p. 161, t. xi, xii, (1848.) The reproductivc cell is formed either
between the halves of an isolated cell, separating from theni in the sub-
sequent development, ( Gyclotella , t. xi, f. d,) or between the halves of a cell
which is a link of a filament, sometimes parallel and bccoining developed in
Connection with the old filament, ( Melosira , t. xi, f. a, c, and Orthrosira,
t. xii, f. e,) sometimes pushing aside the halves of the mother-cell by
secretion of gelatinous matter, and developing at right angles to the old
filament, (Aulocosiru, t. xi, f. b.) •

300

THE PHENüMENON OF

tion of the Diatomaceae, and in itself presents nothing
impossible. The transition from a still incomplete
division to conjugation, is quite as conceivable as the
advance from a first incomplete division to a second,
such as we have become acquainted with in the quar-
tering of cells (p. 254). I will mention one more case
here, which can scarcely be explained otherwise than as a
rcunion of two cells which have begun to divide, namely,
the not very rare abnormal occurrence of division of
individuals into three parts by two constrictions, in
j Euastrum and allied Desmidiaceae. Nägeli has figured
such a specimen of Euastrum ( Cosmarium) Meneghinii,
Breb.* * * § The formation of the spores of Spirogyra
mirabilis f might be caused by a process similar to tliat
in Melosira, if that species really, as Hassall states, forms
spores in all the cells of filaments which do not enter
into conjugation with others ; this would be the more
conceivable in Spirogyra, since the external division of the
cells is preceded in this genus by the division of a
nucleus, and since the division is gradual.

Lastly, the supposed conjugation of the contents of
two adjacent cells in the formation of the spores of
(Edogonium, and of Bulbochcete, with which it has a very
peculiar relationship, deserves an explanation. Decaisne|
and Hassall § have noticed the stränge circumstance,
that in the said two genera, the cell which immediately
precedes the swollen mother-cell of the spore, has little
or no green contents. Hassall thinks we may deduce
from this a passage of the contents of the lower cell into
the upper, and hence compares the process of spore-
formation of (Edogonium with that of the Spirogyra of
the section Bhynchonema , with the distinction, however,

* Nägeli, * Einz. Algen.,’ t. vii, f. 7, b, (as K crenulatum, Elirenb. ?)

t Zygnema mirabile, Hassall, 1. c., p. 156, t. 35.

I ‘Essai sur une Classification des Algues,’ (1842,) p. 39. The figure
given at t. 14, f. 5, belongs to Bulbochcete spheerocarpa , A. Br., ( setigera ,
Auct., ex. p.)

§ L. c., pp. 180—194, t. 50—53, [ßdogonium; t. 54, ( Bulbochcete .)

REJUVENESCENCE IN NATURE. 301

that tlie contents of the one cell do not make their way
into the next cell by a lateral connecting canal, as in the
said Spirogyra , but probably through an opening in the
partition separatin g the two cells. Leon le Giere* has
already correctly objected to the idea of such a conjuga-
tion of the contents of the two adjacent cells, in the
C Edogonia , that we not unfrequently find the lower as
well as the upper neighbour-cell of the sporiferous cell
filled with unattenuated green contents, and that some-
times two, and even three and four cells containing
spores follow in immediate succession. These Statements
are perfectly accurate, and Hassairs endeavours, partly to
set them aside, partly to turn them so that they shall not
oppose liis theory, are unsuccessful. In the first place,
as regards the occurrence of several sporiferous cells in
succession, it must be remarked that two adjacent spore-
cells are met with more or less frequently in all species,
and I have often observed three to four in succession in
(Edogonium apophysatum and Landsbor oughii. + If there
were only two, it might still be asserted that one had
attracted the contents of the cell next below it, the other
the contents of the cell next above it, in order to form
the spore out of coupled contents; but when three or
four sporiferous cells follow in succession, such a coupling
is no longer conceivable. In reference to the contents of
that cell which precedes a single, or several successive
spore mother-cells, it must be noticed of (Edogonium ,
that these are certainly ordinarily, but not unvariably,
poorer in solid constituents, particularly in Chlorophyll,
than those of other sterile cells, but at the same time are
never wholly devoid of colour or of granules, as, on the
contrary, is generally the case in Bulbochcele. A similar,

* ' ®ur !* Fructification du Genre Prolifera de Vaucher,’ ‘Mem. du
Museum,’ iii, (1817,) p. 462. The old name of Prolifera was l’ounded on an
error, and was therefore changed to (Edogonium by Link.

t (Edogonium Landsboroughii, (Hassall,) is the species described and
figured, (t. 23, f. 1,) by Le Clerc, as Prolifera rivularis, Le Clerc repre-
sents four adjacent sporiferous cells in (Ed. Rothii also, 1. c., f. 8.

302

THE PHENOMENON OF

only less striking altern ation, of more richly filled and
poorer, darker and lighter cells, occurs also in tlie sterile
or mferely gonidium-bearing filaments of most of the
(Edogonia ; in tliose species, moreover, whicli have tlie for-
mation of microgonidia mentioned above,* the longer cell
whicli precedes every group of the short cells in which
the small swarmers are formed, is found poor in contents,
like the ante-cell of the mother-cell of the spore. None
of tliese phenomena can be explained by a subsequent
wandering of the cell-contents, produced by Union of
previously separate cells, but are all caused by the distri-
bution of the contents in the very formation of the cells.
For in (Edogonium occur secondary processes of cell-
formation in the filaments, possessing the peculiarity
that the individual cells of the filament divide, not into
like, but more or less strikingly unlike cells, and in such
a way that the upper of the two cells produced by divi-
sion is the shorter and richer in contents, the lower the
longer and poorer in contents. The difference of the
two sistcr-cells is slighter in filaments or fragments of
filaments remaining sterile, as also in those in which
merely macrogonidia are to be formed, and it is mostly
very striking, on the other liand, where the iormation of
spores (or microgonidia) is to take place. The anterior
shorter cell, filled witli more concentrated contents,
becomes, in this case, the mother-cell of the spore. This
process of cell-fonnation, division into unlike halves, is
frequently repeated in the lower cell, this again dividing
into a shorter, fuller, upper, and a longer, lower cell, &c.
Tlius, in sporiferous filaments, a second, third, and fourtli
spore mother-cell may be added successively to the first.
The same is exhibited in the formation of microgonidia,
wherein I have seen the number of short mother-cells of

* (Edogonium echinospermum and apophysatum. See p. 141. The nu-
merous, closely superstratified little cells, which Le Clerc, 1. c., f. 9, figures
between the largcr cells, in a filament supposed to belong to Prolifera
rivularis, ( (Edogon . Landsbor oug hü,) and in the explanation of the plate
takes i'or spiral-tilaments, are doubtless emptied mother-cells of microgonidia.
(SeeThuret.)

REJUVENESCENCE IN NATURE.

303

microgonidia, added on to one another in this way,
amount to six or seven, which indicates a five- to six-fold
repetition of the division in the descending order. The
formation of the globular or ellipsoidal expanding mother-
cell of the spore of Bulbochate is peculiar, and deviates
somewhat from the similar process in (Edogonium . The
spore-bearing cell (the sporangium) usually presents itself
in this genus as a branch at the upper margin of a stem-
cell, and mostly as the first (more rarely the second) cell
of the branch, surmounted by a small bristle-bearing cell,
or even by two cells, one narrowly tubulär, and filled
sparingly with green contents, on which the second,
hyaline and bristle-bearing, is seated like a little lid. The
origin of the branch becoming developed into a sporan-
gium, takes place, as in Cladophora, tlirough formation
of a bagging out process atthe upper margin of the stem-
cell. Into this protruded sac the densely-fluid, green con-
tents of the stem-cell (containing starch-granules) gradu-
ally travel, and this in two portions. In the first place
merely the lower half of the stem-cell loses its coloured
contents, and then it is shut off from the upper, still
green half, by a delicate horizontal partition ; soon, how-
ever, since the protruded sac, not yet shut off from the
stem-cell, continues to grow and to expand toward a
globular form, the green contents travel out of the upper
half of the stem-cell, into the sac-like branch, after which
the partition is formed between this and the stem-cell.
The stem-cell bearing the sporangium offen appears per-
fectly hyaline after this process, and always divided in
the middle by a horizontal septum, a division which
never occurs in the other stem-cells. Only as an excep-
tion have I seen stem-cells more or less densely filled
with green contents, notwithstanding that they bore a
sporangium at the upper margin ; the division of the
cell did not exist in this case. The formation of the one
to two little cells beside the bristle, at the tip of the
sporangium, does not take place until after the protruded
sac is shut off from the stem-cell. From this sketch of

304

REJUVENESCENCE IN NATURE.

the process it will be clear, that in Bulkoclicete , as in
(Edor/onium, a concentration of the formative contents, at
the cost of the sterile sister-cell, is connected with the
procluction of the cell destined to form a spore, but that
there is not any Union of the contents of two previously
separate cells. These cases, therefore, are allied, not so
much to the phenomena of conjugation, as to the pheno-
mena of division into cells of unequal power and of
different destination, mentioned under b* (p. 250).

305

CONCLUDING REFLECTIONS.

Thus have we completed our design of subjecting to
minute inspection, in the example of the development of
the Vegetable Organism, the phenomenon of Rejuve-
nescence, a phenomenon profoundly connected with the
essence of natural life, and lying at the base- of all
progressive movement of life and development, with its
multifariously complicated ascending and descending
vibrations, in the largest as in the smallest circle of
Nature, since this movement is sustained in every
case only by renovation. We have examined it in the
Formation of Sprouts, by which the individual vegetable
stock is expanded into the trank of a family, which, in
essential or inessential combination, distributes the
individual functions amongst its members ; we have
traced it in the sprout itself, in the formation of its
graduated and articulated interlinked structure, in the
great tide of the graduated metamorphosis, as in the
individual waves of this, the Leaves ; finally, we have
recognized again in the smallest sphere of formation, in
which the vegetable strives to establish its every where
only imperfectly attained individuality, in Cell-formation,
with which every cycle of development commcnces, and
by the divided or undivided, homogeneous or hetero-
geneous, combincd or free renovation of which, the
plant carries to fulfilment the multiplicity of structure of
all its organs, and indeed lays the foundation for the
vital continuation of the species beyond the limit of the

20

306

THE PHENOMENON OE

old structure, in renewed construction of the organism.
The examination of Cell-formation leads back, therefore,
in all the wider circles of Rejuvenescence, into the plastic
life of the plant, nay, it leads us even beyond the circle of
the individual development and the related close family
Union in the sprouting vegetable stock, to the true
reproduction of plants, which presents itself, in Con-
nection with the less perfect renovations of Cell-formation
in the preceding circles of development, as the most
decided and freest reconstruction of the cell, and at the
same time as the recommencement dating itself furthest
back, the most complcte Rejuvenescence. As in the
formation of the individual, each new stage arises with
a new section of Cell-formation, so also does the transi-
tion of one individual developmental process to another;
and thereby the intercalation of the individual life in the
compound life of the species, in every case, takes place
through a new impulse in the cell-formation. C011-
sequently Cell-formation is not merely the commencement
of, and the means to, the production of subordinate
tissues ; it is, at the same time, through the law of alter-
nation of gcnerations, Subordination and serial arrange-
ment, prevailing in its progressive renovation, the com-
mencement of every comprehensive complication in the
organism of the plant, of the single organ as of the
special stage in the series of organs, of the single lines of
development or the subordinate axes of the vegetable
stock, as of the individuals becoming developed into
separate Stocks. Thus the consideration of the Cell-
formation in the Rejuvenescence of the Individual is most
intimately connected with that of the Rejuvenescence of the
Species ; indeed so intimately that the boundary between
the two is often difficult to draw, as we have seen in the
foregoing pages, at the lowest stage of the Vegetable
Kingdom, in a portion of wliat are termed Unicellular
plants, plants with generations of vegetative cells separ-
ating from each other (p. 125, &c.) And, just as we see
here, at the lowest stage, the cell-division (p. 233) eise-

REJUVENESCENCE IN NATURE.

307

where belonging to the development of the combined
organism, appearing as a mode of reproduction, so also
in the higher groups of the Yegetable Kingdom, we see
Sprout-formation extricated in most varied ways from the
subordinate relation to the “ whole” of the vegetable
stock, and serving for the formation of independent indi-
viduals.*

The interweaving of the reproduction and the indi-
vidual development is exhibited in a very stränge manner
in that division of the Vegetable Kingdom in which a
decided contrast of sexes first appears,f namely, plants of
the Moss and Fern kind, in which the fertilization, —
which we have been used, from its mode of occurrence in
the whole realm of the Phanerogamia, as well as in the
Animal Kingdom, to imagine connected with the origin of
new individuals, — does not coincide with the commence-
ment of the individual cycle of development, but on the
contrary falls in the middle of this, becoming the means
of transition from a lower to a higher stage of the meta-
morphosis. In both cases it is a single cell in which the
subsequent development is called forth through the in Au-
en ce of the male sex, but in one case it is the primary
cell of the entire generative cycle, i. e. of all the cells
which, by their connected succession, represent the indi-
vidual ; in the other case it is a cell occurring within the
cycle itself, and merely formin g the beginnin g of a new
segment of it. In the Phanerogamia it is the germ-cell, j
formed, after the entire accomplishment of the meta-
morphosis, in the uppermost central cell of the seed-
sprout, (the embryo-sac of the ovule,) which receives the
impregnation by means of the advance of the pollen-
tube up to the embryo-sac ; with it the entire individual

* Reproduction by propagula, (in the Mosses and Liverworts,) by
bulbels, runners, tubors, &c., see p. 40.

f (This expression, as well as various other references of the same nature,
must be checked by comparison with subsequent researches. Tkuret,
Nägeli, Itzigsohn, Tulasne, Berkeley, and Broome, have pointcd out con-
ditions indicating that sexuality is universal. — A. II.)

\ See p. 27G. J

308

TUE PHENOMENON OF

development recommences. In tlie Mosses and Perus it
is the central cell ofthe archegonium,* (a sproutlet which
may be compared with the nncleus of the ovule,) which
is impregnated, in a mariner not yet accurately known,
through the spermatozoids formed in the antheridia;'
the development of this, however, is not a recom-
mencement of the entire cycle, but only an advancc to ä
new and higher stage of the metamorphosis, which,
nnfolding in Connection with the pre-existing preparatory
structure, carries over the individual life only after more
or less complex intermediate stages of formation, to the
production of the true reproduetive cells (spores), with
which, and without further impregnation, the new cycle
of development commences. The point of transition
marked by the occurrence of impregnation, is, again,
different in the Perus and Mosses. In the Mosses, the
transition from the Algoid prothallium to the leaf-forming
stem takes place before the impregnation, which causes
only the development of the spore-forming capsule ; in
the Perus, on the contrary, the preparatory structure
does not go beyond the leafless prothallium, and the
advancc to the leaf-forming stem dcpends upon the im-
pregnation. This mode of viewing the case, very stränge
as the introduction of the impregnation into the midst of
the cycle of the individual development may be, appearS
to me more in accordance with nature, to interrupt less
the natural connection and to correspond betterwith the
graduated course of the metamorphosis, than that given
by the discoverer of the archegonia of the Perns,f
accordingto which the thalloid product of germination of
the spore of the Perns is compared, as the bearer of the
impregnation organs, to the flower of the Phanerogamia,
while the spore from which it is developed is termed a

* See Gottsche, on tlic c Fructification of the J ungermannia3 geocalycesc,’
‘Nov. Act.,’ xxi, ii, 445, t. 30, f. 8. The bicellular condition of the endo-
gonium of Galypogeia Trkhomanes there represented is certainly preceded by
a unicellular stage.

•[• Leszczyc-Suminski, ‘ Zur Eutwickl. der Farrnkräuter,’ Berlin, 1848.

REJUVENESCENCE IN NATURE.

309

flower-bud detached from the raother-plant. Oü such a
tlieory, the new individual cycle of development would
not begin with the spore, but with the central cell at the
base of the archegonium.* Applying tliis view to the
Moss, the first (lovvest) stage in the cycle of its indi-
vidual life would be the formation of the sporangium,
the second stage that of the cönfervoid prothallium, the
third that of the leafy stem, which would finally bear, as
the term of the development, the impregnation-organs,
antheridia and archegonia. The more miaute investi-
gation of the still imperfectly ascertained processes of
impregnation in the Rhizocarpese and Lycopodiaceae, as
also those of the Gymnosperms, (Cycadem and Coniferae,)
aberrant among the Phanerogamia, and perhaps liaving
an affinity to the higher Cryptogamia, will certainly
enable us to place the stränge conditions in the repro-
duction of the Mosses and Perns in clearer connection
with the reproduction of the Phanerogamia, while the
investigation of the Characeae and Plorideae promises a
new point of attachment for the lower department of the
Cryptogamia. t

That an actual impregnation does occur in the Mosses
and Perus is indicated not merely by the well-known
experience of bryologists on the dependence of the fructi-
fication of dioecious Mosses on the social growtli of the
two sexes,J but also the occurrence of hybrids, which
were known in the Perns even before the discovery of the

* According to Suminski’s here certainly incorrect representation, the
cmbryo of the new individual is formed in the central cell of the archegonium,
through the penetration of the tail of a spermatozoid iuto it.

f (The above was printed in 1850 ; the speculation tlien put forth has beeil
realized to an extent scarcely to have beeil cxpected so soon ; the researches
of Mettenius, Nägeli, and above all Hofmeister, have carricd on tliis subject
almost to completion in its main featurcs in the higher Cryptogamia; the
lower Cryptogamia, (Thallophytes,) still require extensive investigation. Eor
the lacts, as also the literature, see the ‘Report 011 the lteproduction of the
Higher Cryptogamia,’ by the present trauslator, iu the ‘Annals of Nat.
Hist., 2 ser., vol. ix, p. 441. — A. H.)

X See Schimpcr, ‘llecherch. sur les Mousses,’ p. 55.

810

THE PHENOMENON OF

impregnation Organs, * and have lately been observed in
the Mosses.t I mention tliis occurrence of hybrids
among the Ferns and Mosses, in order to adjoin some
remarks leading us back to our subject. If hybrids are
formed in Mosses and Ferns, this takes place in a pre-
paratory structure which belongs to the mother-plant ;
the individual entering into the state of hybridation,
(according to the ordinary acceptation of the term,)
becomes composed, consequently, of one part which is
mother-plant, and one part which is hybrid. The hybrid
must develope, as it were, grafted on the mother-plant.
Not until the second generation, that developed from the
spores of the hybrid, can the preparatory structure
assume the hybrid nature, and this, according to the
analogy of most Phanerogamous hybrids, might be sterile
by itself, and only in case of impregnation from one or
other parent species, develope to an ulterior structure
recurring more or less to this. The prothallia of the

* The discovery of the antheridia of the Ferns was made by Nägeli in the
ycar 1842, and published in 1844, (‘ Zcitschr. für Wiss. Bot.,’ lieft 1,
p. 168 ;) the above-mentioncd treatise of Suminski, in which the arehcgonia
were first dcscribcd, dates from 1848 ; the first observation of a hybrid fern
was published by Martens, in ‘Bulletin de l’Acad. lloy.’ de Bruxelles, 1837.
The hybrid there mentioned of Gymnogramma ( Ccropteris ) chrysophylla and
calomelana , subsequcntly named G . Martensii, was soon followed by a second
between G. chrysophylla, and dis/ans, (G. Massoni, Auct.,) described by
Bernhardi in Otto and Dietrich’s ‘ Gartcnzcitung,’ 1840, p. 249 ; Regel bas
enumeratcd several more hybrids from the same gcnus in the 32d No. of the
‘Botanische Zeitung,’ for 1843. I myself found, in the year 1834, in a
mountain valley near Baden, among Aspidium Filix mas, and A. spinulosum ,
(the normal form together witli the variety dilatata ,) several rhizomes, all
within a small space, of a fern which stood about mid-way between the
two species named, and probably was to be regardcd as a hybrid nroduct of
them. I called it Aspidium remotum, and formerly regarded it, aoubtfully,
as a variety of A. rigidum, which it resembled, not only in liabit, but in
degree of formation and mode of decrease of the pinnac. I have never
since been able to find it again, either in the original Station or anywhere
eise in the Black Forest, but it bas maintained its existence in the Botauic
Garden of Carlsruhe, whence it has passed into the gardens of Freiburg and
Leipsic. See Döll, * Rhein. Flora,’ p. 16.

f See Bavrhoffer, ‘Uebersicht der Moose, Lebermoose und Flechten des
Taunus,’ (‘Jahrbuch, des Vereins f. Naturkunde im Herzogth. Nassau,’
5 lieft, 1849,) where two supposed hybrids are mentioned, namely, 1, of
Physcomitrium fasciculare, and 2, of Physcomitrium pyriforme, with Funaria
hygrometrica.

REJUVENESOENCE IN NATURE.

311

Ferns are so alike, and at tlie sarae time so transient, tliat
it would scarcely be possible to institute profitable obser-
vations ; so milch the more is investigation of the hybrids
of tlie Mosses, which, when once attention is directed to
them, will certainly be found in greater numbers, to be
recommended to bryologists. The two hybrid Mosses
observed by Bayrhoffer, seem, from his account, aotually
to have possessed the characters of the mother-plants,

( Physcomitrium fasciculare and yoyriforme,) in respect to
the vegetative organs, while the fruit is stated to have
exhibited, especially in the structure of the peristome, a
distinct approximation to the character of the supposed
father, Funaria liygrometrica. From the occurrence of
nuinerous archegonia upon one and the same moss-plant,
we might expect even to find, when the hybrid impreg-
nation only affected particular of them while others
were fertilized by the proper species, two kinds of fruit
perfected on the same “stock,” normal and hybrid fruits.

Supposing these vievvs to be actually true of the
hybrids of the Mosses and Ferns, it might afford us a
further confirmation of the hypothesis, tliat the indi-
vidual cycle of development of these plants does not begin
with the spore, but with the central cell of the arche-
gonium, which is called into life by impregnation. If,
on the other hand, we keep to the old conception of the
commencement of the individual with the spore, these
stränge processes will appear merely as a further proof
of the intimate connection and interlacement of the indi-
vidual development and reproduction,in which respect they
are of especial interest liere, particularly when we place
them in relation with the cases alreacly mentioned,* which
indicate the possibility of the occurrence of aberrations
ordinarily connected with the reproduction, in the midst
ol the individual development, (in the wider or narrower
sense !) in the higher divisions of the Vegetable Kingdom.

It is well-known tliat those very varieties of plants
which are most important and interesting, those in which

* See page 21.

312

TH E Pll KN OMEN ON OE

the raost considerable deviations from the normal character
of species occur, are not produced on the individual stock,
to whatever influences of nature and art this may be
exposed, but are connected with the reproduction in their
origin, since they grow up, as it were accidentally, from
seeds. Among these are many varieties very striking in
reference to the degree of division of the leaves, e.y.
simple-leaved forms of plants which, in the parent-form,
have ternate or pinnate leaves {Fragaria vesca mono-
phylla * Fraxinus excelsior simplicifolia ) , f and vice versa,
divided-leaved modifications of plants, with normally un*
divided leaves or leaflets ( Ainus glutinös a laciniosa, Betula
alba laciniaia v. dalecarlica) Corylns Avellana laciniata,
Cytisus Laburnum quer cif olius, Vitts vinifera laciniosa
also unarmed varieties of normally spinous plants ( Robinia
Fseudoacctcia inermis) ; || varieties in reference to the colour
of the leaves (Fayus xylvatica sanyuinea ,^[ Corylus tubulosa

* Hiiiscd by Duchesne, in the ycar 3761, from sccds of the common
Fruyaria vesca , and usually returning, wlicn the seeds are sown, to the
parent-form with ternate leaves. Duchesne, ‘Hist, des Eraisicrs,’ p. 124 ;
Godron, ‘De l’Espöce et des Races,’ p. 3G.

f Fr. simplicifolia , W., (/iclerophylla, Vahl.) In De Candolle’s ‘ Pro-
dromus,’ (viii, p. 276,) it is mentioned as a peculiar species, occurring in
England and Ireland, while Sprengel, (‘ Syst. Veget.,’ i, 97,) places its
nativity in North America! De Caudollc, to cstablish the specific distinc-
tion, gives, in addition to the form of the leaf, certain characters derived
from tue size and form of the fruit, which, however, I am compelled to regard
as an unimportant individuality of De Candolle’s specimens, since the trees
of the simple-leaved ash, cultivatcd in the Botanic Garden of Carlsruhc,
agree exactly with the common ash, (F. excelsior,) in their fruit. Persoon,
in reference to the origin of this variety, says expressly, (£Syn.,’ii, 604,)
“ e seminibus Eraxini elatioris vulgaris ortam vidi.” Spenner found, on the
Schienberg, near Ereiburg, a completely aualogous vai'iety of Uu/jus Idceus,
with leaves resembling those of 11. arcticus.

J Both occur, probably only isolated, in Sweden and Lapland. In
gardens they are increased by cut.tings, and wlien sown probably recur to the
cntire-leaved parent forms. The other examples named are known only as
garden-plants.

§ The parsley-vine, as it is called. See Babo and Metzgei-, ‘Weinn.
Tafeltrauben,’ p. 33, h. ii, 10.

|| A single specimen of this was obtained by Descemet from a sowing in
1803, and itis now generally diffused. Its seeds furnish the spiny parent-
form again. (See Clievreul, ‘ Consideratious gen. sur les Yariations,’ &c.
‘Auu. des Sc. nat.,’ 3me ser., vi, 157, 1846; Trans, in ‘Journ. Hort.
Society,’ vol. vi, p. 61, 1S5 1.)

The copper-beech uuiversally dill'used in gardeus is derived from a

REJÜVENESCENCE- IN NATURE.

313

atropurpurea ), colour and doubling of the flower ( Tulipa,
Dicinthus , Primula, Dahlia , &c.) ; as also, finally, the
numerous varieties, chiefly marked by the condition of
the fruit, which we have among our cultivated orchard
and other fruits. The origin of the varieties mentioned
here does not depend so much upon an alteration
gradually insinuating itself into the external conditions
of existence, as upon a development, under favorable
conditions, of the multiformity possible within the limits
of a certain type, which is implied especially in the fact
that very different varieties may arise from one and the
same sowing, even from the seeds of one and the same
fruit, and tliis without influence of impregnation from a
foreign source, and under equal external circumstances.*
The development of tliis multiplicity takes place ordinarily,
as stated, by means of reproduction, and it may clisap-
pear in the same process ; the new varieties grow up from
seed, and may in like manner return to the parent-form
by sowing. ßut sometimes a similar production and a
similar retrogression of the variety takes place by means

forest near Sondersliausen, in Thuringia ; it is propagated by cuttings,
since when sowu it mostly retums to the common green beech. See
Bechstein, ‘ Forstbot.,’ f. 1, p. 229. Ibid., (267,) mention is made of a
copper oak, (Quercus pedunculata sanguinea,') of which a single tree is said
to exist in the Lauchner Forest, near Gotha.

* According to Yan Mons, this sometimes goes so far that a peculiar
variety springs from each single seed, e. g., from the ten seeds of a pear,
were aeveloped an equal number of new sorts of pear. Cultivation of course
has an influence upon the production of new varieties, yet not on the indi-
yiduais directly exposed to its effects, but on their progeny. In most cascs it
is impossible to demonstrate a definite relation of the influence of cultivation
upon the qualities of the varieties tlience arising; it appears rather, on the
wliole, as if the unusual conditions, favorable to a luxunant state of develop-
ment, afl'orded by cultivation, awakened in the plant the inward impulse to
the display of all those variations possible within the more or less narrowly
circumscribed limits of the species. According to the experience of gar-
deners, in particular of the celebrated Belgiau orchard-fruit grower, Van
Mons, tliis impulse is only gradually awakened in the wild plant subjected
to cultivation, often requinng several gcnerations, until it has attained its
maximum and is finally extinguishcd in the formation of constant varieties.
At, the same time, the fact of experience is remarkable, that improved
varieties propagated by cuttings acquire so much the more incliiiation to
return to the parent. form the longer they are propagated in this way. (See'
Godron, ‘ De l’Esnocc ct des Races,’ p. 83, wherc also are euumejated the
treatises of Vau Mons not within my reacli here.)

314

THE PHENOMENON OE

of mere vegetative development, so tliat even the indi-
vidual vegetative “stock” may comprehend several
varieties within its limits at successive points in time, or
at collateral points of space. Here refer many well-
known facts, as, for example, tliat the wild Hepatica
(H. nobilis) witli its lovely blue six-leaved flowers, if
transplanted from the sliady mountain-groves into a
garden, usually produces, even in the next year, double
and in addition mostly red flowers ; in like mariner that
the Periwinkle {Vinco, minor ) often acquires white or
brownish-violet flowers in place of its blue ones, in
gardens. If we sum up mentally the successive annual
products, such Stocks striking into variety appear com-
posed of two modifications of the species ; the Hepatica,
for instance, the annual Rejuvenescence of whicli is
effected by direct continuation of the main axis,* * * § looked
at in tliis way, represents a stem bearing simple blue
flowers at its lower parts, and double red ones above.
But that which we only see lrere by the mental combina-
tion of what is separate in time, meets us in actually
united in other cases, in which the formation or retro-
gression of the variety only occurs on particular sprouts
of a branchcd stock, or in which several of the modifica-
tions in which the species may appear, present themselves
so distributed on different parts of one and the same
stock, that it is impossible to determine to which modifi-
cation the stock origin ally belonged. Cases of botli
kinds are known in Vines and Currants, which bear two
kinds of bunches of fruit, f of Melons witli two kinds of
fruit, | of Rose “Stocks” which bcar two kinds of
flower,§ &c. I have observed cases of the first kind in

* See p. 54.

f See Metzger, ‘Landw. Pflanzcnk.,’ ii, 913 and 917, where it is stated
of the red Traminer tliat it often brings forth white bunches when old, and
of Klavner, (Burgundy,) that it not unfrequently bears blue and red bunches
on the same “ stock I have often seen isolated red-berried bunches on
“ Stocks” of Ribes rubrum with white berries.

j See Sageret, ‘ Ann. des Sc. nat.,’ t. viii, 309, (1826.)

§ On the variety of Rosa Eglanteria, with üame-red flowers, (R. bicolor,

REJUVENESCENCE IN NATURE.

315

tlie Laburnum with incised leaflets ( Cytisus Laburnum
quer cif olius), as also in tlie more or less incised variety of
the Beech ( Vagus sylvatica asplenifolia) in tlie Carlsruhe
Botanic Garden, the ordinary parent-form reappearing
with the perfectly rnarked variety, on isolated sprouts of
these plants. The same phenomenon has also been
observed in the Parsley Vine.* The strängest cases
belonging here are not those in which the modifications
are combined with the sprouts, as subordinate individuals
of the “ stock,” but those where the process of Separation
of the varieties extends only to some limited part of the
organs, or even to single groups of cells, and perliaps
even to the individual cell, as exliibited by the pheno-
menon so frequently occurring among cultivated plants,
of plants with variegated leaves ( e . g. in Cabbages,f)
divided irregularly into several colours, striped or dap-
pled flowers (in Tulips, Pinks, Roses) j and fruits (in
Gourds, Apples, Grapes, &c.)§ One of the most beau-
tiful examples of this kind is offered by Mirabilis
Jalappa . The three varieties, with deep-red, nankin-
yellow, and white flowers, are not unfrequently found
two or even all three united on the same “ individual,”
in such a manner that there are Stocks with the
flowers striped with: 1. red and yellow, 2. red and
white, 3. yellow and white, and 4. red, yellow, and
white ; and not unfrequently, also, isolated single-coloured
flowers present themselves on the same stock, these being

Jacq.,) I have often seen isolated shoots bearing pure sulpliur-yellow
flowers, (. R . lutea, Mill.,) sometimes even flowers divided into the two
colours.

* See Babo and Metzger, 1. c., p. 35, where the authors state that tliey
have detected, on vigorous Stocks of this variety, isolated branches with
leaves which were merely five-parted and undistinguishable from the leaves
of the white Guledel.

f Here belongs what is called the federkohl, a variegated winter cabbage
{Brassica olcracea acephala ,) which represents a mixture of the green and red
cabbajp, (Metzger, ‘ Kohlarten, ’ 20.)

% The striped rose, frequent in gardens, is a Rosa gallica, with white, red-
striped flowers, on which sometimes occur half or even entirely red flowers.

§ l’hus in the two-coloured Morillon, ( Morillon panache.) See Babo and
Metzger, ‘Wein, and Tafeltraubeu,’ 169, heft. ix, t. 4.

316

TIIE PHENOMENON OP

of three kinds, red, yellow, and white, in the föurtlt
case.

Analogous cases of heterogeneous composition of the
vegetable stock occur in Ziybrids of Phanerogamous plants,
through return to the parent form on the hybrid stock
itself, whereby it may happen that two specifically dif-
ferent species may present themselves uriited, together
with the hybrid, upon the same stock. This, however,
is a far rarer phenomenon than the occurrence of several
varieties on the stock, for hybrids, as the celebrated
experitnents of Kölreuter* showed, ordinarily return by
way of reproduction, to one or otlier parent species, after
liaviug beeil impregnated by this for several generations.
The only certainly known instance of the recurrence of a
hybrid plant to the parent species on the stock itself, has
beeil found recently in the generally diffused garden
intermediate species, between Cytisus Laburnum and
C. pnrpureus (6'. Lab urno -purpur eus, Walpers,f C. Adami,
Poiretj, | tlie hybrid nature of wliicli, in spite of the con-
trary assertions of Loudon§ and Reissek, || cannot well be

* See bis preliminary reports (‘Vorläufige Nachrichten) of experiraeuts
relating to the scxcs of plants, particularly the third series, (17G6,) p. 51,
where is dcscribcd the “■complctc conversion of one natural species of plant
into another,” namely Nicoliana rustica into N. paniculata. The first
impregnation of N. rustied with N. paniculata produced a hybrid, which
assumed completely the' character of the parent plant in the “ fourth
asccnding step,” i. e., after three transitional generations produced by
repeated impreguation with N. paniculata.

Nicotiana kustica $ >

f ‘ Repertorium,’ i, 634, (1842,) where two figures of it are cited. (The
‘Botanist,’ i, t. 7. ‘Bot. Register,’ t. 1965.)

J The authorship of the name C. Adami is thus stated everywhere;
where Poiret has given a notice or description of Adaui’s new plant, I do not
know.

§ According to Loudon, (as appears from a note in the ‘ Bot. Zeitung,’
1843, p. 133,) Adam obtained bis new Cytisus by grafting a bud of C.
pnrpureus on C. alpinus (?). 1 cannot consult the source of the statement

hcre eited, (‘Gard. Mag.,’ xii, 225, and xv, 122.)

|| According to Reissek, (Haidinger, ‘Berichte über die Mittbeil, von

paniculata $ S
paniculata

paniculata

paniculata

paniculata

$ ] N. paniculata.

REJUVENESCENCE IN NATURE.

317

doubted, since the French authors* unanimously assert
it, and this assertion finds strong support in the sterility
of C. Adami, observed by Henon and Seringe, and con-
firmed by the behaviour of the specimens in the Carlsruhe
and Freiburg Gardens. C. Adami bears its narae after
the nurseryman Adam, of Vitry, near Paris, who raised
it in the year 1826. The mother-plant is said to be
C. Laburnum, the father C. purpureus .f In its arbo-
rescent growth and raany-flovvered racemes it far more
resembles the common Laburnum, than the low shrubby
C. purpureus with its two-flowered inflorescences hidden
between the leaves ; but the racemes are shorter and not
so full of flowers. The dirty red colour of the blossom,
the smoothness of the leaves, calyx, and germens, which
are villous in C. Laburnum , remind us more again of
C. purpureus. Düring the last ten or twelve years it
has been observed in most diverse places (thus in Lyons,

Freunden der Natur in Wien,’ i, p. 12, extracted in the ‘Flora,’ 1846,
p. 623, and 1848, p. 26, in Hornschuch’s essay on the ‘sporting’ of plants,
with which extract alone I am acquainted,) a shrub of Gytisus Laburnum, in
the Vienna Botanic Garden, which had previously always borne only the
yellow blossom proper to this species, suddenly produced, in the spring of
1846, on some of its branches, the red flowers of C. Adami, and liere and
there red and yellow flowers mingled in the same racemes ; nay, a twig per-
fectly representing C. purpureus is said to have sprung from a yellow-flowering
branchof this shrub. Hornschuch found, iu the occurrence thus narrated by
Heissek, an analogue of the many othcr remarkable stories of transformation
which he reported from old and recent sourees, (for example, the growth of
a Lolium branch from a wheat stock, the occurrence of isolated oat spikelets
on wheat spikes, the transformation of oats into rye by a particular mode of
treatment, &c.,) and a striking proof of tlie possibility of conversion of one
species of plant into another. Without entering gcnerallv into the con-
tcsted question, the present case admits of a simple, and I tliink not very
hazardous explanation, in the assumption that an unknown hand had
engrafted scions of C. Adami in the said shrub of C. Laburnum, that at the
time of the observation there exislcd recurrences of the C. Adami to
C. T Minimum, and that the shoot of C. purpureus mentioned grew out of
such a £gaft, (certainly not out of a Laburnum branch.)

* Henon (and Seringe,) ‘Ann. des Sc. phys. et. nat. de la Soc. d’Agricult.
de Lyon,’ ii, 375, (1839.)— Buchinger, ‘ Flora,’ 1842, i, 37S.-Kirschlegcr,
‘ Institut.,’ 1843, p. 372, and ‘ Essai deTeratol. Veg.,’ 71, (1845.)— Ohe vreul,
‘Ann. des Sc. nat.,’ 2 ser., vi, 186, (1846.)

f Kirschleger, 1. c.

318

THE PHENOMENON OF

Strasburg, Schiltigheim, Munich, Vienna, Carlsruhe,
Freiburg (and England), that single shoots present them-
selves upon the Stocks of C. Adami , which (witliout any
mediating transidons)* represent quite purely the yellow-
flowered and villous C. Laburnum , or, what is much more
striking from the great difference of the habit, branches
perfectly characterised as C. purpur eus. Ordinarily only

one or other of the two parent species appear in t.his
way,f but sometimes both on the sarae stock.j: The

formation of sprouts, and indeed the formation of twig-
buds, is consequently the turning point here, witli which
the recurrence of the hybrid into the parent-species
occurs; the recurring buds develope into stronger or
weaker twigs, which in all parts belong entirely to one
or other parent-species (stem-, leaf-, flower-, and fruit-
formation). Sometimes, however, the case occurs of the
recurrence to the parent-species first in the small twigs
of the inflorescence, i. e. in the transition to the single
lateral buds of the raceme, whereby the flowers belonging
to the parent-species originate in the inflorescence of the
hybrids and mixed racemes are formed. Three kinds of
these are possible, namely : 1, C. Adami mixed with

* Kirchleger says, indeed, — “ J’ai pu meme, en 1814*, observer toutes les
transitions de ces trois sortes de branches (avec leurs inflorescences et leurs
fleurs) les unes aux autres,” but this assertion is certainly incorrect.
Kirscldeger was certainly deceived by tbe mixed inflorescences and flowers,
which I shall describc more minutely.

j- I bave observed tliis in Carlsruhe and Freibur" wliere I never saw
both parent species produced out of the same stock. Buchinger found the
same. I mention tliis circumstance expressly in order to remark tliat the
explanation given by Chevreul, (1. c.) by which the recurrence of C. Adami
to its parent species as a decomposition of the hybrid into its two portions
(somewhat as in a Chemical decomposition) is inapt.

+ This is expressly asserted of the tree occurrin" in the garden of Prof.
Schweighäuser, at Schiltigheim, which was deseribed by Kirschleger. (This
oeeurred also in the specimen in the garden of L.W. Dillwvn, Esq., of Swan-
sea, wliere the shoots bearing the blossoms of the parent species were fertile,
ripening seed, while the hybrid blossoms were sterile as usual. — A. H.)
Siuce it is probable that all the specimens of C. Adami diffused in gardens
are cuttings of a single motker-stock, the distinction, whether only one or
both parent-species present themselves, becomes of less importancc.

REJUVENESCENCE IN NATURE.

319

flowers of C. Laburnum ; 2, C. Adami mixed with flowers
of C. purpureus ; 3, C. Adami mixed with flowers of both
parent-species. Hitherto I have only observed the first
of these three cases, to which also belong the mixed
racemes described at Henon, the isolated yellow flowers
(belongmgtoC,.Z«fomrczm)beingdisplayed among the ordi-
nary rose-red flowers of C. Adami.* * * § These mixed racemes,
at the same time, exhibit the peculiarity that the yellow
flowers set fruit, while the rose-red fall off immediately
after the flowering, so that in the recurrence of C. Adami
to one or other parent-species, the fertility lost in the-
hybrid reappears. But the strängest thing that happens
in the recurrence of C. Adami to C. Laburnum, is the
phenomenon of mixed flowers, which belong, both in the
calyx and the corolla, partly to C. Adami, partly to
C. Laburnum , in which even single segments of the calyx
and single petals are halved, the former appearing
half reddish-brown and smooth ( C . Adami), half grey-
green and villous, the latter half red (C. Adami) and
half yellow (C. Laburnum ). A raceme in which this
occurredf exhibited, carefully counted up, among the
32 flowers it bore, 21 unaltered flowers of C. Adami,
3 pure flowers of C. Laburnum, and 8 mixed flowers, the
7 of which, compared in the subjoined fable,}: exhibited
the following conditions of intermixture in calyx and
corolla. §

* In reference to the hybrid nature of C. Adami it is not unimportant to
remark that the reverse phenomenon, namely, racemes of C. Laburnum
intermixed with single flowers of C. Adami, has not been observed citlier by
others or by myself. If these mixed racemes depend on a partial recurrence
of the hybrid to the parent-species, this casc cannot occur at all.

t In the Carlsruhe Botanic Garden, May 1843.

X Compare here the outlines in plate Y and the accompanying explana-
tions. ihe eiglith mixed flower was not in perfect preservatiou.

§ I neglected to examine accurately the condition of the stamens and
ovaries of these flowers.

320

THE PHENOMENON OF

No. of the Flower.

Sepal.

Fetal.

Adami

H

Laburnum

i

l|

“• i

Adami

4

4

Laburnum .....

1

1

' Adami

2^

Laburnum . . . . . .

H

H

‘ Adami

Laburnum . . . . . .

2a

2^

3

2

Adami

2^

2

Laburnum ......

2^

3

r Adami

2|

1

[ Laburnum . . . . . .

2i

4

VII. -

Adami

1

0

Laburnum

4

5

Togetlier.

jio

>

Ü}10

5i

10

511
HI
fiio

3} 10

io

o1}

It need scarcely bc remarked, that thcse mixed flowers
appearing on Cytisus Adami , are fullv analogous to the
previously examined examples of mixed flowers (and
fruits) ; the only distinction is that there it was partial
sporting of one variety into the other, here a similar
reversion of the hybrid form into the mother-species.

We have devoted our attention to tliis entire series of
stränge cases, in whicli the ordinary law of the invaria-
bility of the specific and individual character within the
vegetable stock appears to be suspended, because they
serve us as a proof of the intimate connection of the
course of development of the individual with the history
of the species. As the aberrations in the course of the
individual metamorphosis are especially fittcd to afford us
an insight into its law, — since they reveal the internal
connection and the essential similarity of its foundation,
through unusual transitions, through anticipatory* * or
retrogressivet interweaving, or flnally by complete return

* Compare the frequent cases of a petaloid uppermost cuphyllary leavcs
in Tulips, Callha, Trollius , the petaloid calyx of the double Primroses, of
Rubus coesius witli petaloid inner sepals, (Act. Nat. Cur./ xv, i, t. 31, f. 2,)
of Sempervivum iectorum with stamens of the inner circle passmg into

Ca+) Rosa, Ranunculus, Adonis, with the outermost, sepal passing into euphyl-
lary formation ; similarly Rosa and Linum with scpaloid first petal ; the half
double flowers with partial conversion of the stamens into petals, &c.'

REJUVENESCENCE IN NATURE.

321

of the formations to the starting point,* — so must the
last-examined deviations from the usual mode of transition
to new organic destinations, belonging ordinarily to the
cycle of development of the species, not of the individual,
point to the common characters, which connect the tran-
sition from individual to individual, with the transition
from one structure to another within the individual
organism of the plant.

In the Introduction we endeavoured to seize the points
common to these two domains, as the process of Bejuvenes-
cence , and the minute investigation of the phenomena of
Rejuvenescence in the course of life of plants, carried out
in the three main sections of our reflections, enable us now
the more readily to examine from the same point of view
the Rejuvenescences of the species through reproduction.
The transition to the new individual finds its analogue
within the species, in Cell-formation, as the freest modi-
fication of it, as we liave seen especially in the formation
of the germ-cells (germinal vesicles) of the Phanerogamia ;
it finds its analogue, further, in Sprout-formation, here
again representing the most independent modification of
it ; for while the sprouts belonging to the cycle of deve-
lopment of the “ stock” are unfolded, either in permanent
combination with the mother-stock, or if they separate
from it, are connected with it in the earliest period of
development, yet the embryo, as primary sprout of a new
vegetable “stock,” is always free from its earliest forma-
tion. As in the various gradations of the interlinking
( Gliederung ), which the vegetable stock acquires through
its Rejuvenescences in Cell-formation, Leaf-formation, and
Sprout-formation, we could not avoid recognising sub-
ordinate kinds of reproduction, since we could not deny
even to the cell, but especially to the sprout, a certain
individual import ; — so, on the other hand, the series of
individuals produced by true reproduction appears as an

* As in the cases of flowers appearing grecn, ( anthochloroses ,) in which
all parts of tlie flower often return more or less periectly into the euphyllary
formation.

21

322

THE PHENOMENON OE

interlinking (Gliederung), only in a free condition, and the
species as a whole, developing itself in tliis formation of
links, as it were a vegetable “ stock” of a liigher kind.

That we might go still further in tliis direction, in the
attempt to seize the conception of the natural continuity
of the essence, we have already indicated in the Intro-
duction. For as the individual appears as a link of the
species, so does the species as a link of the genus, the
genus as a link of the family, of the order, the dass,
of the kingdom ; the kingdoms of Nature even as the
great principal links of the organism of Nature; a view
with which, indeed, we givc to the Natural System its true
and objective import, which is entirely lost in the mere
subjective abstract conception of the natural clivisions.*

* The truc rccoguition of the organism of Nature and its composition of
mcmbcrs or links, as objective facts, expressed by Nature itself, is essen-
tially neccssary to the higher shapiug of Natural History as a unity. The
tenucncy existing in the contrary direction, disregarding onc-sided pliilo-
sopliic hypothescs, is causcd among botanists chicny by the previously pre-
vailing cultivation of the Artificial System, and the difiiculty of the cou-
struction of the truly Natural. Linmeus himsclf, morcover, the fouuder of
the most important Artificial system in botany, regardcd species and genera,
emphatieally, as objective works of Nature, (‘Phil. Bot.,5 § 1G2,) and
cxplaincd tiic classes and Orders of the Artificial System as a makeshift, until
the Natural were dctected, (§ 101.) It is remarkable to find even such
authors as arc inclined to an objective view of the conceptions of the
genus and species, making the assertion that merely the individual really
exists, (thus e. g. in Spring, ‘Ucbcr die Naturhist. Begriffe von Gattung,
Art und Abart, 1838, p. 22, 23.) To acknowledge the individual as really
existing, and deny the natural actuality of the morc comprehensive com-
plexcs of the organism of nature, is au inconscqucncc, depending on the
deception by which the individual sccms to be immediately given in the
phenomenon, whüe it is easy to see that the individual, as such, i. e., as a
single being, can only be conceived mediately, in the recognition of the inner
unity which runs through the series of phenomena, in which it displays
itself. Child, youth, and man, Caterpillar, chrysalis, and bulterfly, are not
to be conceived from externa! appcarance, but only in consequence of tlieir
im material esscnce, as one and the same single being. The external con-
tinuity of the successive series of appearances of the individual, affords no
grouud for regarding it essentially di Heren tly from the comprehensive sys-
tematic complexes, for the same reeurs even in the successive appearances of
the species, where successive links (the individuals) stand in direct Con-
nection in’ the reproduction. That the individual has no right to be
considered as real in other senses than the species, genus, &c., is indicated
especially in the alternation of generations, as it is called, which exhibits the
remarkable case of the individual, in the higher sense, (the biological
individual,) breaking up into a limited or unlimited series of subordinate

REJUVENESCENCE IN NATURE.

323

Ifc is true tliat tlie common origin and the liistorical Con-
nection among the links of the more comprehensive
divisions of the Vegetable Kingdom, cannot be so readily
demonstrated as is the case with the history of the
individual in Cell-, Leaf-, and Sprout-formation, and the
history of the Species, the formation of the Individuals

(morpliological) individuals, wliich sometimes are developed in permanent
Connection, as compound family-stocks, as in tlie “ stock” formation of the
zoopkytes and plants, caused by sprout-formation, sometimes separate com-
pletely, as in the Entozoa, Aphides, Medusas, and in the case not unfrequent
in the Yegetable Kingdom, of natural Separation of the buds. Indeed
Nature goes still further in plants, for it gives to the smallest circles of
formation subordinate to the morphological individual, usually called the
cells, such au independence of the vital functions, that these may be
regarded in a certaiu sense as individuals, which, in the higher plants, lead
a Gfe interwoven in the totality of the organism, but in the lower, separating,
often acquire an isolated individual existence, (pp. 124, 125, et seq.,) in
both cases representing an alternation of generations of subordinate kind in
their succession and multiplication, effected by a process analogous to repro-
duction. According to the axiom that merely the individual really exists,
those who reeognise the individual of the plant in the cell, must interpret
the cells ofthe plants as alone real beings, and the stock, the sprout, the leaf,
&c., as inessentiai aggregates. But where remains the individuality of the
cell, as extemal appearance, when we see that even this has its transforma-
tion, its successive renovation, so that, externally regarded, it does not
remain the same, but constantly becomes another, so loug as the vitality
endures in it, (pp. 176 et seq., 226 et seq.) ? The reality, therefore, can-
not be immediately conceived, not even the smallest circle, in the detaehed
phenomenon, but in every case only mediately in the recognition of essence
ou which the continuity of the phenomenon depends. Now just as the
individual is realised through a chronological succession of formatious and
material division into subordinate links, this is likewise realised in a
complex of a higher Order, representcd by the individuals, by means of which,
iust as in the individual, it runs through its circle of forms in chrono-
logical succession and material extension ; in like manner the genus, as a
more highly generalised whole, is realised through the circle of the species,
the family through the genera, &c. ; so finally Nature, as a whole, is realized
through the process of development, which brings into existence all the
links of its organism, succcssively and contemporaueously, and the totality
of each System of links in all fliese circles certainly cannot be called less
real, in its representation through the links, than the parts which, without
the whole, would not exist. For the assertion that merely the individual is
real to have any meaning, the species, genera, familics, classes and kiugdoms,
must be regarded as individuals of a higher Order : a view which may be
considercd well founded, in so far as all these complexcs dopend upon
special practical destinations of natural life, just as Nature, as a whole, as
shaped out upon our planet, is to be regarded as an individual, which,
although created according to the same eternal primary type, certainly
possesses its own mode and way, different from the Nature of the other
celestial spheres.

324

THE PHENOMENON OE

effected by reproduction, and the circle of Varieties which
come into existence in the course of reproduction ; but
the flora of the ancient worid,* and the geographical
distribution of the plants of the present epoch,f afford us
important indices at least, pointin g to the connection in
time and space of the history of development of the
Vegetable Kingdom as a whole and in its parts.

We have examined Rejuvenescence in general and
more particularly in the processes of Vegetable life, and
rising from the narrower circle of the development of the
single being, we have sought for it again in the wider
circles of theOrganism of Nature, and in this way arrived
at the conviction, that it lies at the foundation of all sub-
division in life, all graduated development; that it is
this, throngh which not only the single being progresses
from one formation to another, but the whole chain of
being is carricd onward from generation to generation ;
throngh which the smallest step of the organic structure
is introduced, the greatest transitions of Nature carried
into cffect, and the metamorphosis in the individual, likc
the transformation of Nature as a whole from agc to age,
brought about. At the conelusion, tlien, of our reflec-
tions, the question will not appear premature, if we ask,
What property of life it really is which declares itself in
the Phenomenon of Rejuvencscence? In the first place, a
general acknowledgment must be made that the orderly
succession of phenomena of Rejuvenescence, which pre-
sents itself to us in every natural development, cannotbe
explained through the effort of external natural forces,
but points to an internal cause. Every train of develop-
ment exliibits in its course an adherence to plan which

* See pp. 7 — 9. The law of development becomes more and more
evident in the newcr worlcs on the character of the vegetable kingdom in
ancient epochs. See, in refercnce to this, the latest comparative view by
Ad. Bronguiart, in bis ‘ Tableau des genres de Veget. Fossiles,5 p. 93, (1849.)

t Note, for example, the native country of the family of Cacteue, the
cactus-like Euphorbise, the Epacridece, the group of the Heliophilcse in the
family of the Crucifei se, the rieh genera Stapelia , Pelargonium, Aloe, Agave,
&c.

RKJ UVENESCENCE IN NATURE.

325

can only liave its ground in an internal vital destination ;
it exhibits, at tlie same time, an independence of all
external influences which testifies to the internally given
force of vitality. The manner and way in which the
internal immaterial nature of life manifests itself more
particularly in the Phenomenon of Rejuvenescence, we may
call, in the true sense of the word, a reminding ( Erin-
nerung), being the exertion of a power which, in Opposi-
tion to the outward revelation and superannuation of life
in appearance, grasps anew the ideal ( innere ) destination
and turns it outward with new force, in order to carry it
over every onesidedness or imperfection in the external
representation, to repeated (and in proportion to the pro-
gress of the development) more and more refinecl com-
plication of the original vital purpose. The recollection
(or reminding) of the inherent clesign of life presents
itself to us within the determinate stage of development
in the repeated representation of the same vital form ; it
presents itself to us, retrogressively, in the reproduction
of long overpassed, or, in advancing development, in the
production of new vital forms, which are, in both cases,
however, involved in the original destination. Must we
not call it a reminding (or recollection) when, in the
course of generation, the old specific nature returns to
life with each new individual? It is not still more
strikingly a reminding when, in the course of the Reju-
venescences, a long-relinquished parent-form suddenly
returns to existence ? as we have seen in the striking
back of varieties and the recurrence of hybrids into the
mother-species, with so remarkable an instance of which
we have become acquaintecl in Cgtisus Adami ? The
advance to new shapes, proportionecl to the course of
development, brought about through the Rejuvenescence,
has been minutely examined in the metamorphoses of the
individual being, where it is most accessible to our limited
observation; does not this revealmost distinctly the inter-
nal preservation and making good of the original vital des-
tination, through all intermediate destinations which are

326

11E J U VENESCEN CE IN NATURE.

required for its entrance iuto combination with the lower
steps of natu re, from which the development starts ? As
in the Individual, then, so ceftainly in all Nature, with
which the individual is combined through the common
destination lying at the very foundation of all life. This
connection is testified to us by the unity of the final term,
in which we see the structure of entire Nature receive its
key-stone. Is it not hcre again the recollection of the
original destination of crcated life, which carries up step
by step the development of Nature, from the first stirrings
of life, through infinitely numerous links of Reju-
vencscence, to the appearance of Man ? Finally, is it
not this which impels even Humanity to Rejuvenise itself
from race to race in ever rnore deeply searching recollection
of its high purpose, comprehending that of all Nature,
and connecting it with the Etcrnal Source whence all
internal Law and Force of Life derive their origin ?

*

PI I.

PALMOGLCEA MACROCOCCA. Kalz?

Tu££e*i West, Oircano Liüi .

tnrcL SfWesC Clrnrno Tinp

EXPLANATION OE THE PLATES.

PLATE I.

Palmoglma macrococca, Kützing ?*

( Coccochloris Brebissonii, Thwaites).

All the figures are from specimens frora the Höllenthal,
near Freiburg. The figures 21 — 28 and 1 — 13 of
PI. II represent the conjugation of the cells, and the
consequent formation of the spores, as described at
pp. 135, 202, and 285 of the text. Magnified 350 diam.

Fig. 1. Acell with a distinguishable gelatinous envelope.

Fig. 2. A cell which has attained the maximum of
longitudinal growth.

Fig. 3. A cell beginning to divide.

Fig. 4. A pair of cells produced by division, the two
portions still in contact.

Figs. 5 and 6. The same, but the two daughter-cells,
still enclosed by the common enveloping membrane of
the mother-cell, have already separated, without however
exhibiting distinguishable special envelopes.

Fig. 7. Two cells, considerably elongated and possessing
special coats, enclosed by the common mother-envelope.

Fig. 8. A cell of moderate length with two vesicles in

* The species of the genus Palmogleea, established by Kützing, caimot be
certainly determined eitlier by the cliaracters given in the ‘ Spec. AJgarum,’
or by tue figures given in the * Tabula; Phycologicm.’ In the species
represcntcd in our plate, the jelly-like cell-envelopes are sometimcs dis-
tinguishable singly, sometimes not, which renders doubtful even the section
in which we are to seek the species. The gcrm-cclls vary in length from
aSj to ,5 millim., average, therefore, -|J3 to ^ of a line, so that the distinctions
lounded on size, given by Kützing, likewise fnrnish no safe criterion.
From the variability of the characters, it is not impjrobablc that inany of the
species brought forward by Kützing, in particular P. riepestris, macrococca,
vesiculosa, lucida, rufcscens, and crassa, will have to be combined as forms of
one and the same species.

328

EXPLANATION OP THE PLATES.

the interior, the nature of wliicli is doubtful ; betvveen
the two, and more to the side, exists a ligliter space
(frequently observable).

Fig. 9. A similar cell, in wliicli the dark-green portion
of the contents forms a pretty sharply circumscribed
mass witli a constriction in the middle.

Fig. 10. The same cell turned one quarter round, the
green mass appearing narrower and with a bright spot
beside it. ✓

Fig. 11. Another cell in the same position, with a still
more compressed green body in the interior, reminding
us of the genus Mesotamium, Näg. (cEinz. Algen.,’
t. iv, B.)

Fig. 12. The same cell seen from above.

Fig. 13. A similar cell, in wliicli the plate-like green
mass is interrupted in the middle.

Fig. 14. Two very short cells, shortly after their pro-
duction by division, with plate-like compressed green
masses placcd obliquely in the interior.

Figs. 15 — 16. Rows of cells in contact, without dis-
tinguishablc cnveloping membranes, such as are some-
times produced by rapidly succeeding divisions in very
active Vegetation. The arrangement of the cells in this
case shows that the division constantly occurs only in
one direction.

Figs. 17 — 20. Cells treated with tincture of iodine,
whereby the green masses in the interior are coloured
brownish, and a dark brown nucleus becomes visible,
wliicli, however, does not appear sharply defined, and
certainly contains no starcli.

Fig. 21. A cell preparing for conjugation, furnished
with a lateral wart-shaped projection.

Fig. 22. Two similar cells in contact by their wart-
shaped projections.

Figs. 23 — 27. Cells conjugated by Union and anas-
tomosis of the lateral processes, with the connecting
piece of variable length.

Fig. 28. The same, but one cell Crossing the other.

PI. II.

Taffem West CWamo Litk

tJ&nry {U)t/iny rzfesdfil

114 p ALMOGL CE A MACROCOCCA. 15-22 SCHIZOCHLAMYS GELAT1NOSA

EXPLANATION OE THE PLATES.

329

PLATE II.

Figs. 1 — 14. Palmoglceci macrococca.

( Continued from Pl. I.)

Fig. 1. Two cells, laterally connected, pushed aside
in opposite directioris.

Figs. 2 — 4. Conjugated cells, in which the end of one
is attached to the side of the other.

Eig. 5. Conjugation carried further, by the widening
of the connecting piece. (The cells from fig. 21, pl. 1, to
this figure, already exhibit evident drops of oil in the
inferior.)

Eigs. 6 — 9. Transitional forms produced by still fur-
ther advanced conjugation, but still two-lobed ; they
often persist in this form.

Figs. 10 — 12. Seed-cells formed by complete union
of two conjugated cells. These, as also those represented
in 6 — 9, are almost filled with large drops of oil, and
have a thicker coat than before the conjugation.

Fig. 13. Seems to be an union of three cells, which I
only met with once.

Fig. 14. A group of four cells, enclosed by a tough
coat, probably produced by the division of the contents
of a seed-cell.

Figs. 15 — 22. ScJnzochlaniys gelatinosa , A. Br.

This forms a gelatinous coating over water-plants, as
also swimming masses, on the peat-moors of the Black
Forest. (See pp. 181, 230, in the text.) Magnified 600
diameters.

Figs. 15 — 16. Two cells which tlirow off their cell-
membrane by regulär Splitting into two halves, without
themselves dividing.

Fig. 17. A cell which, after throwing off its earlier

330

EXPLANATION OF THE PLATES.

cell-membrane, has formed a new one, somewhat removed
from the green internal cell at one side.

Fig. 18. The cell-membrane thrown off by Splitting
into four pieces, with simultaneous division of the cell
into two daughter-cells.

Fig. 19. As in fig. 18 ; but the two new cells have
already become coated with cell-membrane.

Fig. 20. The same; but the detaclied cell-membrane
split only into two parts.

Fig. 21. The detached cell-membrane has brolcen up
into four portions, the internal cell has become trans-
formed by double halving into a group of four decus-
sating cells.

Fig. 22. The same; but the cells have already
scparated and become coated with new cell-membrane.

PEDIASTRUM GRAbTULATUM.

Tuffen West CtromoLifk

Toni & West Chramn hnp

EXPLANATION OF THE PLATES.

331

PLATE III.

Pediastrum granulatum , Kütz.*

Numerous modifications, all derivecl from one and the
same little pool of water, near Freiburg. Figs. 1 — 9
represent the reproduction. (See pp. 161, 184, 200,
250.) Magnified 400 diameters.

Fig. 1 . An old disk, in great part emptied by birth of
gonidia. The emptying of the cells of this specimen,
the first in wliich I observed the reproduction, took place
before my eyes in the order of the letters a to e ; this was
on a day in autumn, (Nov. 24, 1 848,) in the afternoon ;
the empty cells not marked hacl lost their contents before
the commencement of the observation, probably in the
morning of the same day. Several of the empty cells,
(for instance, a, b, c, e ,) distinctly exliibit a cross slit,
through which the contents have been discliarged ; in the
rest the emptying has taken place on the opposite side,
so that the slit is in visible in this position of the disk. One
cell is in the act of discharging the gonidia, these having
in part entered into the projecting portion of the hernia-
like vesicle formed by the swollen innermost lamella of
the mother-cell membrane, in part still remaining in the
internal cell-cavity. Three other cells still possess their
perfect contents, but in different conditions. Two of
them are filled by sixteen extremely closely crowded
gonidia, only half of which are visible, as they form a

* In giving a name to this species I select that determination which
sccrocd least doubtful ; I must observe, howcver, that several of the species
distinguishcd by Kützing probably belong to the same species, so particularly
P. Boryanum, K. ; subulatum , cruciatum , K. ; and also in part P. Selenaa ,
Auct., namely, with the exclusion of P. Selencca, Ralfs., ( lunare and elegans ,
Hass.); and P. Selenaja, Niig. ; (pertvsum, K.) The leugth of the horns,
as also their clavate rounding off, is variable ; punctatea condition of the
ccll-wall, on the contrary, I found constant ; but lt is only distinguishable in
full-grown and empty specimens.

332

EXPLANATION OF TIIE PLATES.

double layer. The third, not yet emptied cell, is in the
actual transition to the formation of gonidia ; it exhibits
the first divison of the contents into two halves, one of
whicli already appears halved again. — The arrangement
of the sixteen cells of the entire disk is an unusual one,
1 + 6+9, the outer circle in t.his case being incomplete,
and a cell of the inner circle, opposite the break in the
outer circle, possesses one horn.

Fig. 2. The new-born family, immediately after the
birth, seen from the corncr. It is derived from the cell
a of the disk represented by figure 1. The innermost
lamella of the mother-cell has wholly emerged from the
old cell as an extrem ely tliin vesicle enclosing the
gonidia ; the gonidia in the interior of the mother-vesicle
moving actively.

Fig. 3. The same family, in the same stage, seen on
the surface.

Fig. 4. The same, in a later stage, namely, a fall
quarter of an hour after birth, in the same position as
fig. 2. The gonidia, now at rest, have arranged them-
selves in a plane in the plane of section of the equator of
the mother-vesicle.

Fig. 5. The same, in the same stage, showing the
surface. The sixteen gonidia, united into a colony, form
a circular sixtecn-cellcd disk, in the arrangement l-j-5
-{-10 ; but they do not adhere firmly togetlier. A sliglit
emargination is already visible on the outside border of
the cells.

Fig. 0. Another young family in the same stage as
fig. 5, about half an hour after birth. The arrangement
5 + 11.

Fig. 7. Another of the same age, exhibiting the
arrangement 6+10.

Fig. 8. The families represented in figs. 2, 3, 4, 5,
one hour after birth. The emargination of the cells has
aclvanced further.

Fig. 9. The same again, but four hours after the
gonidia ceased to move, (four hours and a half after

EXPLANATION OF THE PLATES.

333

birtli.) The emargination of the border-cells has passed
into the formation of horns. The cells are not even yet
closely connected together, but exhibit spaces between
them, so that in this stage the disk exhibits a resem-
blance to that of Pediastrum pertusum, (Näg., £ Einz.
Alg.,’ v. 2, as P. Selenaa,) which species, however, does
not lose the oritices in the full-grown condition. Not
until the second day, after an interruption during the
night, of the rapid changes of form of the cells, do the
cells become closely applied together ; the horns acquire
their proper shape and length at the same time.

Eig. 10. A half-grown disk of four cells, two of which
meet in the middle. A starch-grain is visible in eacli
cell, as is usual in the middle age. The mother-vesicle
is still visible here, wliile in ordinary cases it disappears
altogether by the second day.

Eig. 11. An older four-celled disk, the four cells
meeting in the middle. The families formed of four
cells are extremely rare in this species.

Fig. 12. Disk ofeight cells, in the arrangement 2-{— 6,
which is more frequent in this species than the arrange-
ment 1+7. The inner two cells are notched on the
outer border, which is connected with the position of the
two outer cells opposite to them.

Fig. 13. A similar disk, but with the inner two cells
not notched, but interposing an obtuse-angled Prolonga-
tion into the commissure of the outer cells altern ating
with them.

334

EXPLAN AT TON OE THE PLATES.

PLATE IV.

Pediastrum granulatuni, Kg.

( Continued from Pl. III.)

Eig. 1. Disk of eight cells, placed 1 + 7, clerived from
the same mothcr-disk as the four-celled disk represented
in fig. 11, of Pl. 3.

Eig. 2. Eull-grown eight-ccllcd disk, 1 + 7. The Con-
tents of the cells dark green, and granulär ; -the starcli-
grains no longcr visible. The cell-walls in the mterior
of the disk are tingcd slightly crimson, which colour,
however, only occurs sometimes in full-grown specimens.

Eig. 3. Eight-celled disk arranged 1 + 6+1, a very
rare exceptional case.

Eig. 4. Disk in 1 + 5+10, which is the most frequent
case with sixteen cells, (see fig. 5, Pl. III.)

Eig. 5. Disk of sixteen cells, 6 + 10, the inner six
differently arranged from those of fig. 7, Pl. III.

Eig. 6. A similar one, but the outer circle so closely
adjoined to the inner that the arrangement appears
spiral.

Eig. 7. Abnormal disk of fifteen cells, in which, how-
ever, one in the outer circle is larger tlian the rest, and
doubtless Stands in the place of two, from omission of the
last division in the formation of gonidia. The likewise
irregulär arrangement may, therefore, be regarded as
5+10+1.

Eig. 8. Elliptical disk of sixteen cells, 5 + 10.

Eig. 9. A similar disk, but the five inner cells in a
different position.

Eig. 10. Elliptical disk of thirty-two cells, 7 + 11 + 14.
The colonies of thirty-two cells aje rarer in this species

2.

H.rz

Aes: ..ui;

Jcrd i.'Vfist lTnrnmo Ittt»

PEDIASTRUM GRANULATUM

EXPLANATION OF TUE PLATES.

335

than the sixteen-celled ; I liave observed in these, besides
that figured, the following kinds of arrangement :

1 + 5 + 10 + 16
1 + 6 + 10 + 15
1 + 5 + 11 + 15
1 + 6 + 11 + 14 (spiral.)

5 + 11 + 16

6 + 10 + 16 (sub-spiral.)

7 + 10 + 15 (elliptical.)

I liave never met with specimens with sixty-fonr cells
in this species, but Nägeli, (1. c., t. v, b, 1, g,) figures a
sixty-foiu’-celled specimen, arranged 2-j-7 + 12-f-19-)-24}
in the scarcely specifically distinct P. Boryanum.

336

EXPLANATION OF THE PLATES.

PLATE V.

Cytisus Adami.

Diagrams of mixed flowers, partly striking back to
Cytisus Laburnum, on which see p. 319 in tlie text. The
outer circle represents tlie calyx, the brown parts of it
belong to C. Adami, the green to C. Laburnum. In the
inner circle (corolla) the red colour signifies C. Adami ,
the yellow C. Laburnum.

A

raffen Yfcs». Cbromo r.rtJx.

HYBRID FLOWERS FROM CYTISUS

A'.'Wosl Gkroino Imp

AD AMI & C LABÜRNUM

INDEX.

Acalypka, 89.

Acantlius, 92.

Ackillea, 30.

Acklya v. Saprolegnia.

Aconitum Napellus, 37.

Actea, 55, 73.

Adonis vernalis, 84.

Adoxa, 29, 31, 55.

Adventitious buds, 22.

Ai uga, genevensis, 22.

Alisma, 98.

Allium Schcenoprasum, 97.

Ainus glutinosa laciniata, 332.
Alternatious of generations, 51, 52,
106, 126, 322.

Althsea rosea(Pollen-formation), 256.
Ampelideae, 94.

Amylum v. Starch.

Anabaina, 146.

Anagallis, 22.

Ananas, 57.

Anapbytosis, 102.

Anarrliinum bellidifolium, 71.
Anemone nemorosa, 29, 55.

Angelica sylvestris, 86.

Antkoceros, 257.

Apetalous flowers, 94. [250.

Apkanocksete, 184, 209, 230, 233,
Apiocystis, 132, 209.

Apios, 33.

Aquilegia, 99.

Araucaria, 59.

Archidium, 232.

Armoracia rusticana, 97.

Aroideee, 89, 91.

Arthrosiphon, 178.

Ascidium, 125, 127, 185, 186, 200,
Asimina, 79. [209, 267, 286.

Asparagus, 44.

Aspidium remotum, 310.

Aster, 30.

Balsaminese, 33.

Bambusina, 291, 295.

Bartonia, 248, 252.
Batrachospermum, 150, 151.

Beeck v. i'agus.

Berberis, 77, 90.

Betula alba laciniata, 312.

Bet.ulacese, 91.

Botrydium, 128, 193, 220, 274.
Botryocystis, 159, 209.

Breadtk of tke base of leaves, 67.
Bromus, 40.

Bryopsis, 129, 140, 166, 268.

Buds, 18.

descent of, 56, 57.
Bulbocksete, 141, 151, 156, 157, 183,
201,209. [303.

pretended conjugation of,
Bupleurum rotundifolium, 86.
Buxus, 36.

Calliopsis bicolor, 85.

Calluna vulgaris, 226.

Calycantkus, 77.

Campanula medium, 98.

Carex, 101.

Carpels, 65.

Carpiiius, 36, 53, 62.

Castanea, 89.

Catapkyllary leaves, 62, 84.
Caulerpa, 129, 174.

Cell-contents, 155, 171.

Solutions in tkis, 194.
Cell-formation, 121, 123.

abnormal, 266, 281.
free, 164, 167, 238,
259, 272, 275.
by constriction, 254.
by division, 168, 232,
240, 250.
period of, 224.
Cell-membrane, 156, 176.

lamiuation, 220, 229.
solution of, 189.
strijjping of, 18, 230.
tearing up of, 177.
skinning of, 180, 188.
Centunculus, 34.

Ckaetomorpha, 185, 186, 268.
Chajtopkora, 139,151, 156, 183, 208,
224, 231, 253.

Ckantransia, 143, 151, 183, 231.

Ohcirci

Ckaraceaj, 152, 175, 234, 247. [250.
Ckaracium, 125, 185, 209, 229, 230,
Cheirantkus Clieiri gynautkerus, 97.
Ckelidouium magus, 77.
Ckimonantkus, 78.

Cklamidococcus, 138, 158, 174, 184,
196, 205, 211, 216, 224, 229, 238,
250, 258.

Chlamidomonas, 214, 216.

22

338

INDEX.

Chlamidomonas, obtusa, 215.

tingens, 215.
Chlorococcum, 213, 260.
Chroococcaceae, 131, 174, 190, 197.
Cliroococcus, 131.

decorticans, 182, 230.
Ckytridium, 185, 261.

Cicendia filiformis, 25.

Cilia of thc Algse, 157, 158.

disappearance of, 230.

Citrus Medica, 82.

Cladophora, 150, 174, 185, 199, 220,
235, 236, 239, 240, 253, 268.
Closterium, 133, 175, 281, 291.
accrosum, 291.
curtum v. Penium.
juncidum, 292.

Leibleinii, 292.
lineatum, 291, 292.
Lunula, 140, 204, 289.
striolatum, 292.
Trabccula v. Docidium.
Coccoloba, 60.

Cocconcma, 286.

Colcocbmtc, 141, 270. [253, 298.

pulvinata, 151, 1 83, 208,
scutata, 142, 183.
Commarum, 78.

Compositae, 85, 89.

Conferva bombycina, 184, 205, 209.
Conjugation, 282, 283.

of similar cclls, 284.
of dissimilar cells, 296.
Convallaria, 34, 68, 90.

Corypha umbraculii'cra, 27.
Cosmarium v. Euastrum.
Crassulacem, 94.

Crocus, 67.

Cruciferse, 33, 90, 96, 97.

Cuticle, 191, 244.

Cycas, 12, 27, 58.

Cyclamen, 34.

Cylindrocystis, 287.
Cylindrospermum, 146.
Cymatonema, 141.

Cyperacea;, 33, 91, 98.

Cystococcus, 125, 185.

Cystoseira, 248.

Cytisus Adami, 24, 31. [315.

Laburnum quercifolius, 312,
Derbesia, 185, 186.

Desmidiacese, 133, 139, 174, 247,
283, 290.

conjugation of, 290.
movement of, 203.

Desmidium, 294.

Destruction of thc Cell, 176.
Diantbus, 76.

Diatomaceaj, 132, 139, 190, 247.

conjugation of, 285.
Diclinous flowers, 100.
Dictyospbaerium, 132, 209, 238.
Didymoprium, 291, 295.

Digitalis purpurca monstrosa, 58.
Diphyscium foliosum, 177, 230.
Division of Generations, 86.
Docidium, 291.

Trabccula, 180.

Doubling of Flowers, 79.
Draparnaldia,,- 139, 151, 156, 183,
Drosera, 98. [208, 224, 231.

Dysphinctium, 203.

Ectocarpus, 125, 142, 185.

Elymus Europreus, 87.

Emilia sagittata, 86.

Endococcus, 213, 268.
Endospcrm-cells, 248, 278.
Enricbment-sprouts, 37.
Entcromorpha, 184, 250.

Epilobium, 30.

Epimedium, 55, 73, 77.

Equisetum, 180.

Ericaccse, 94, 97.

Eriocaulon, 35.

Erysiphe, 261.

Erytlirrea pulcbella, 26.

Euactis, 147, 178.

Euastrum, 133, 224, 295.

margaritiferum, 181, 294.
Menegbinii, 300.

Eunotia, 286.

Eupborbia, 22, 36, 37.

Eupbyllary leaves, 63, 84.
Exococcus, 254.

Fagus, 20, 31, 62.

sylvatica sanguinca, 312.

asplcnifolia, 315.

Fasciation, 122.

Fermentation Fungi, 254.

Fems, 27, 307, 309.

bybrid, 309.

Festuca, 40.

Fir v. Pinus.

Floridem, 253, 255.

Fragaria vesca monopbylla, 312.
Fraxinus excelsior simplicifolia, 312.
Fucbsia, 78.

Fucoidese, 142, 183, 253.

Fucus, 126, 142, 183.

Fuirena, 91,

INDEX.

339

Fumaria, 79, 90.

Fundamental Organs of the plants,
108, 112.

Funkia caerulea, 276.

Galanthus nivalis, 56.

Generations, successions of, 32.
di vision of, 35.
alternations of, 51, 52,
106, 126, 344.
Gentiana, 83, 92.

Geraniaceae, 93.

Germ-cells, 134.

Germinal vesicles, 167, 276.
Gesneriaceae, 33.

Glaux, 95.

Glechoma hederacea, 59.

Gleichenia, 114.

Gloeocapsa, 131, 132, 182, 190.
Gloeococcus, 159, 209.

Glceocystis, 131, 161, 182, 190.
Glyceria aquatica, 87.

Gompkonema, 238, 286.

Gongrosira Sclerococcus, 183, 209.
Gonidia, 134, 137, 140.

active 137, 141, 148, 157,
158, 162, 169, 183, 261.
duration of motion of, 212.
period of motion of, 221.
Gonium, 159.

Gramineae, 33, 86, 91, 98, 100.
Haematococcus pluvialis v. Cklarny-
domonas.

Haiving of cells, 233.

Haplosiphon, 150.

Hassallia, 150.

Hedysarum coronarium, 33.
Heliconia cannoidea, 73.

Helickrysum arenarium, 22.
Helleboms fcetidus, 72, 76.

niger, 29, 55.

Hepatica, 29, 54, 314.

Hcracleum, 69.

Himantidium, 286.

Hormidium, 131.

variabile, 208.
Hyacintkus, 18.

Hyalotkeca, 291, 295.

Hybrids, formation of, 42, 310, 310.
Hydrocharis, 101.

Hydrodictyon, 125, 127, 137, 156,
171, 185, 186, 190, 197, 199,
208,219,220,261.

Hydrophyllum canadense, 72.
Hymenopkyllum intcrruptum, 115.
Hypecoum, 79.

Hypericum, 28, 30.

calycinum, 77.

Hypnum abietinum, &c., 40.
Hypsopkyllary leaves, 63, 84.
Impatiens Balsamina, 35.
Increase-sprouts, 38. [124.

Individual, tke vegetable, 19, 23,
Isoetes, 28, 53, 144, 189, 197, 200.
Isoetaeese, 255.

Istkmosira, 291, 295.

Jacquinia, 79, 93.

Jamesonia, 114.

Jasione perennis, 71.

Jasminese, 93.

Juncus, 97, 107, 111.

Juniperus, 59, 65.

Jurinea Pollichii, 22.

Labiatse, 33, 90, 98.

Leaf-formations, 51, 101.

of tke Algffi, 152.
disappearanceof,83.

Leafy-skoots, 57.

Leaves, formation of 62, 84.
Leguminosse, 33, 90, 99, 194.
Lemania, 154.

Lengtk of leaves, 70.

Leptomitus lacteus, 270.

Ligustrinse, 33.

Lime v. Tilia.

Limnantkes, 96, 99.

Linaria, 22, 31.

Litorella lacustris, 42.

Lolium, 40, 87.

Lycopodiacese, 144, 255.
Lycopodium annotinum, 59.
Lysimackia Nummularia, 31, 34, 59.
Lytkrum, 30, 80.

Makonia, 70, 71, 77, 90, 96, 115.
Malvacese, 94, 96, 99.

Marsilia, 194,

Mastickonema, 147, 187.
Mastickotkrix, 147-
Melaleuca, 57.

Melocactus, 27.

Melosira, 139, 299.

Mentka, 28, 30.

Mertensia, 114.

Mesocarpus, 135, 288.

notabilis, 289.
Metamorphosis, 60, 320.

ascending, 60.
descending, 52.
vibrating, 52.
Mirabilis Jalappa, 315.

Mousonia, 93, 96.

INDEX.

340

Mosses, hybrid, 310.

Mougeotia, 288.

Musa, 74.

Myrtaceae, 98.

Nardus, 87.

Narcissus, 53, 56, 80.

Naslurtium pyrenaicum, 22.
Nicotiana, 92, 98.

Nostoc, 145, 155.

Nucleus, 174.

division of, 241, 24S.
solution of, 195, 241, 248.
Nymphsea, 79.

Oak v. Quercus.

CEdogonium, 141, 148, 150, 156,
157, 161, 163, 170,
175, 183, 196, 201,
209, 212, 224, 227,
231, 247, 281.

apophysatum, 141, 162, 301.
capillarc, 170.
cchinospermum, 141, 302.
fonticola, 141, 170, 224.
Landsboroughii, 164, 301 .
supposcd conjugationof, 300.
(Enothcra bicnnis-muricata, 42.
muricata, 71.

Oil (fixcd), 193, 195, 200.

disappearance of, 204, 205.
Ophiocytium, 260.

Ophioglossum, 18, 59, 189.
OrchidcEC, 33.

Ornithogalum sulplmreum, 276.
Oryza, 88.

Oscillaria, 131, 197.

Oxalidese, 93.

Oxalis Acetosella, 54.

stricta, 30.

Oxyria, 77.

Pachy sandra, 35.

Paeonia, 71, 73.

Moutan, 96, 99.

Palmellaceaj, 131, 174, 190, 213.
Palmogloea, 133, 135, 202, 285.
Pandorina, 159, 209, 212, 224.
Panicum mirabile, 88.

Papilionacese, 98.

Paris quadrifolia, 26, 34.

Parnassia palustris, 226. [249.

Passiflora (Pollen-formation of), 248,
Pediastrum, 125, 161, 184, 200, 209,
Pedicularis palustris, 71. [250, 266.
Penium, 292.

curtum, 181, 190, 203.
Jenneri, 289.

Perigynium, 100.

Petals, 64, 93.

Peziza, 186, 260.

Phaseolus, 33.

Phlox paniculata, 72, 76.

Phyllotaxy, 116.

Physalis Alkekengi, 30.

Phytolacca, 95.

Pinus, 32, 39.

(Pollen-formation of), 248,
249, 256, 257.

Plantago ianceolata, 57.

major, 35.

Platyzoma, 1 14.

Plcurococcus, 131, 258.

miniatus, 182, 213, 230.
Poa alpina, 57.

bulbosa, 57.

Podophyllum; 77.

Polemoniacea;, 33.

Pollen-grain, 228, 254.

Polygala, 77.

Polygone«;, 94, 97, 98.

Polygon u m , 9 6 (vide addend. et corrirj. )
Prasiola, 131.

Primordial utricle, 156, 169, 170.
Primulacese, 33, 95, 97, 99.
Propagation of cells, 227.
Protococcus, 125, 127. [258.

viridis, 209, 212, 213,
Pteris aquilina, 59.

Pulmonaria oflicinalis, 71.

Pyrola, 55.

Quartering of cells, 254. [71.

Qucrcus, 18, 20, 31, 36, 54, 62, 65,
pedunculata sanguinea, 313.
Rafllesia, 26.

Reconstruction of thc Cell, 226.

partial, 272.
with halving, 232.
with quartering, 254.
with division into
many portions, 259.
Resorption of cells, 193.

Respiration of plants, 217.
lthamneffi, 94.

Rheum, 96.

Rhizocarpeae, 144, 255, 256.
Rhododendron, 54.

Rhynchonema, 289.

Ribes, 78, 314.

Rivularia, 147, 148.

Rivularica:, 146, 178.

Robinia Pseud-acacia inermis, 312.
Root, 111.

IN DZX.

341

Root-sprouts, 22.

Rosa Eglanteria, 314.

gallica, 315.

Rosacese, 98, 99.

Rubus Idseus iutegrifolius, 312.
Rurnex, 77, 100.

Rumex Acetosella, 22.

Rutacese, 80, 99.

Salvia, 90.

Salix, 53, 101.

Saprolegnia, 252, 268, 298.

capitulifera, 188, 269.
ferax, 185.

Sarcococca, 36.

Scenedesmus, 250.

Schizocklamys, 181, 230.

Sckizonema, 139, 286.

Sckizosiplion, 147, 178.

Sciadium, 187, 209, 260.
Scropkularinese, 33, 90, 98.
Scutellaria, 90.

Scytonema, 147, 178, 186.
Scytonema;, 146, 178.

Seed-cells v. Spores.

Sepals, 64, 92.

Series of generations, 32.

Sesleria, 87.

Sirogonium, 288.

Skinning of eells, 180, 188.

Slipping out of cells, 182, 231.

imperfect, 187.
Solanacere, 98.

Solanum tuberosum, 30, 37, 53.
Solidago, 30.

Spermosira, 146.

Sphseroplea, 164, 271, 281.
Spliserozyga, 146.

Spirogyra, 135, 175, 180, 196, 201,
224, 239, 241, 281, 289.
lubrica, 244.
mirabilis, 300.

Spores, 134, 164.

Sprout-formation, 21.

relative to character, 38.

to economy, 38, 41.

Stamens, 64.

Starch-grains, 198, 206.

solution of, 195, 197.
Staurocarpus, 134, 281, 296.
Stauroceras, 287.

Staurospermum v. Staurocarpus.
Stellaria media, 95, 98, 99.
Stem-formation, 108, 110.
Stigeoclonium, 139, 156, 163, 183,
208, 224.

Strengtheuing generations, 29, 43.
Strutkiopteris, 108.

Sustaining sprout, 37.

Swarm-cells v. gonidia.

Swarmiug out of cells, 183.
Syzygites, 290.

Tamarix, 40, 98.

Tanacetum, 30.

Terminal bud, 53.

Tetmemorus, 291.

Tetracbococcus, 258.

Tetraspora, 132, 209.

Tetraspores, 255.

Thesium, 90.

Thuja, 40.

Tkyils, 253.

Tilia, 45, 53, 100.

Tiliacem, 94.

Tolpothrix, 147, 186. [257.

Tradescantia (Pollen-formation of),
Transformation of pistils into sta-
mens, 97. [278.

Transitory Cell, in tbe embryo-sac,
Trifolium montanum, 33.

Triticum, 40.

Tropseolum, 31, 39.

Tubp, 18, 26, 56, 68, 313.

Ulothrix, 125, 156, 159, 175, 200.
zonata, 148, 184, 208, 223.
Braunii, 177, 183, 208, 250.
Ulva, 125, 184, 250.

Unicellular plants, 124.

Urococcus, 178, 230.

Yaleriana officiualis, 69.

Yalonia, 180, 273.

Vaucheria, 128, 140, 157, 163, 174,
183, 209,212,221,251.
conjugation of, 296.
Veratrum, 68.

Veronica Ckamsedrys, 59.

Yesicle, Chlorophyll, 199.

Yesicles, germinal, 167, 275.

Vinca minor, 314.

Vines v. Vitis.

Vitis, 46.

vitifera laciniosa, 312, 315.
Volvocinese, 158, 208, 216, 250.

eye of, 209.

Volvox, 159.

Willow, v. Salix.

Zonaria Pavonia, 179, 248.

Zygnema, 175, 288.

Zygnemacete, 333, 135, 164, 174,
Zygogonium, 288. [180, 287.

ericetorum, 177.

ON THE

ANIMAL NATURE OF DIATOMEiE,

WITH AN

ORGANOGRAPHICAL REVISION OF THE GENERA,

ESTABLISHED BY KÜTZING.

By Professor G. MENEGHIN1.

TRANSLATED FROM

THE ORIGINAL ITALIAN EDITION,

(Venice, 1845.)

'

NOTE.

By au oversight, thc references to pages in the Annotations, p. 496 et seq,,
are crroneous, not having bccn altered to adjust tliem to tlie difference of
thc paging in tliis volurnc and the original cssay. The following corrections
must be made:— 4 = 346; 7 = 348; 8 = 349; 9 = 350; 10 = 351;
12 = 353; 13 = 354; 10 = 357; 20 = 300; 23 = 303; 25 = 364;
90 = 421; 100 = 445.

In rcference to the discussion on the subject of measurement at p. 418,
it may be worthy of attention that Kiitzing confesses that Ehrenberg’s
figurcs, drawn with an ampliflcation of 300, are not smaller, but sometimes
cven larger tlian bis own, whicli are magnified 420 times. (Note on
Epithemia ocellata , ‘Kicselschal. Eacillarieu,’ p. 34.)

ON THE

ANIMAL NATURE OE DIATOMEiE.

The Diatomeae are microscopic beings provided witli
a siliceous sliielcl or sbell, on which account tlieir form
remains unchanged ; they are easily subjected to observa-
tion, and easily distinguished from other minute organ -
isms, wbether belonging to the animal or the vegetable
kingdom. The earlier observers considered them to be
animals undoubtedly; and animals they were decidedly
pronOunced by Ehrenberg. On the other hand, almost
every Algologist has actually taken them for plants, and
in this opinion all are agreed who have more recently
treated on the elementary structure of organic beings,
and on the distinctions that constantly separate animals
from plants, even at their first origin. In Support of
their animal nature, the important observations of Ehren-
berg certainly possess great value, but these are in-
sufficient ; because the same arguments have induced the
illustrious author to include in the same dass of Poly-
jastric Infusoria the Desmidiem also, which now bv
universal consent are acknowledged to be true Algae.

If a new opinion do not actually spring from between
these two, there is revived under another name the an-
cient theory of Phytozoa and Zoophytes, the Nemoures of
Gailion, the Psychodiarian kingdom and the Arthrodieae
of Bory St. Vincent, the Green Matter of Priestley, the
metamorphoses of Agardh, and we are advancing directly
to the theory of spontaneous generation, and the other of
defective specific limitation, in accordance witli which

346

ANIMAL NATURE OF DIATOMEAE.

species and genera, whether aniiual or vegetable, are con-
sidered to be transitory forms of tke same organic type.
Kützing does not admit any essential distinction between
animals and vegetables. He maintains that the same
being may, at various periods of its development, assume
one nature or the other. The following is his theory in
a few words. Every organic being is constituted of
vegetable elements and animal elements, and according
as the one or the other prevails, the being becomes an
animal or a vegetable ; in the first stages of the develop-
ment of superior beings, and permanently in those of
inferior rank, the two elements are equally balanced.
And this is the case, in the author’s opinion, with the
Diatomeae, wliich, on this account, cannot be absolutely
referred either to one series or the other, but constitute
the ring or circle which unites together all organic beings
into one kingdom. Long controversies have sprang up
between the supporters and the opponents of this doctrine,
who, to obtain victory, mutually accuse one anotlier of
logical errors, of sophisms, and of paradoxes.

The analysis of this controversy would be tedious and
of little profit ; whilst on the other hand, sound logical
principles may guide us to a rigorous estimate of the
facts. And, in truth, the natural Sciences are entitled to
boast of a language that is adequate to the purpose, if
we avoid the abuse of Ontology. The words Animal and
Plant, like words in common use, as Species, Genus, Order,
Class, King dom, do not denot.e any existing thing in par-
ticular. To the naturalist there exist individuals only,
as to the philosopher there exist only bodies. Species is
a synthetical comprehensive expression, abstracted from
all the individuals so similar to each other, that they
may all be considered as originating from the same
parents. Genus is a still larger abstraction, comprehend-
ing all the species that resemble each other in some im-
portant characters ; and so we advance to the denomina-
tions animal and plant, expressions of ideas existing only
in the mind of man, and therefore entirely subordinate

ANIMAL NATURE OF DIATOMEiE.

347

to impressions already received and to those which may
be received hereafter. These ideas are hence more or
less incomplete in every observer, nay, incomplete in all,
because no one has seen every animal or every plant. On
this acconnt we not unfrequently meet with organisins of
an ambiguous nature, which at first sight appear equally
to belong to the animal and the vegetable kingdom. But
yet with regard to this ultimate division of organic
beings, we ought to proceed in the seltsame path which
we find necessary to follow in respect to the first divisions
of Species and Genera. When a naturalist meets with a
species that appears to belong to two different genera,
and to form a transition, so to speak, between one and the
other, he decides according to the importance and the
value of the cbaracters, either to modify the definitions
of the two genera, or to propose a new one, or to fuse
both together into one. He would sin against Ontology
should he assert that he found the two genera included
and "combined in the ambiguous species. The genus has
existence only in our minds, and not in the species. In
the latter we can only discover some or all the charac-
teristics of the genus ; that is, certain signs which con-
stantly subsist in every sister species, whatever may be
their diversity in other respects. Thus Kützing, when
he says that in the Diatomeae the two elements, the
animal and the vegetable, are combined and in equilibrio
with each other, gratuitously imagines the idea of a com-
bination, which in reality can only take place between
different substances, and hence he applies his conjecture
to the expression, instead of applying the latter to the
former. And he draws his conclusion from the example
he uses, instituting this same comparison between the
organic and inorganic kingdom, and deducing from it
analogous consequences ; the gradual transition from one
to the other is as it were their conjunction, through
the same intermediate ring or circle of Diatomeae.

The phosphate of lime, he says, which constitutes so
large a portion of the bones of animals, the silica of

348 ANIMAL NATURE OE DI ATOMEN.

Diatomese, and the other mineral elements whicli are
found united witli organic tissues botli of animals and
plants, represent the combination of the inorganic witli
the organic kingdom. According as the one or the other
prevails, life or deatli is triuraphant. The word mineral
is in this instance so exalted, as to signify, not an in-
tellectual abstraction, but something unknown, ideal,
metaphysical. With the same right that he terms phos-
phate of lime or silica mineral, I can equally apply the
word mineral to carbon, hydrogen, or to the triple com-
bination of O. H. and C., or the quadruple combination
O. H. C. A., since these substances also, as well as fclie
formcr, do not solely of themselves manifest those general
properties whicli we comprehend in the abstract ex-
pression Life. Nor ought. we to allow ourselves to be
deluded by the abuse with whicli chemists apply the
word orfjanic to some material elements of living beings.
It is a convenient but dangerous mode of expression.
The same remote elements constitute living and dead
bodies ; and admitting that some combinations are found
in the former whicli are wanting in the latter, and that
otliers can by no means be produced artificially, still
wliat we term life does not reside solely in these. The
same Chemical combination may be alive or dead, without
any knowledge of the cause on our part. It is only by
comparing tliis with other known facts, and not by Ob-
servation, that we suppose its proximate cause to be the
mutual arrangcments and the motion of molecules. So
that, whenever any substance forms an integral portion
of the tissues of a living being, it does not belong to the
mineral kingdom, but to this being, and therefore to the
organic kingdom. It is only when, independently of
those manifestations which constitute life, this substance
within a living being obe_ys physical and Chemical laws
as it would obey thein out of the body, (like calculous
concretions within animals, and crystals in the interior of
vegetable cells, and incrustations whether internal or ex-
ternal,) so that tliey issue from the medium within which

ANIMAL NATURE OF DI ATOME.®.

349

they live or the vehicles tliat introduce thern, and en-
viron, suffocate, and kill the animals or the plants or
their tissues : — then only I should denominate this sub-
stance a mineral thus associated with an organic being.
In the shields of a Diatomean, as well as in the discs of
Acalephse or Gasteropoda, in the epidermis of Crustacea,
in the bones of Vertebrata, this so-called inorganic sub-
stance is, at least in part, within the same conditions as
the albumen or fibrine or any other proteine combination
which constitutes the rest of the tissue. In the Diatomeae,
as well as in the Mollusca, the solid shield adapts itself
to the successively growing dimensions of the animal, as
in the Vertebrata the bones grow pari passu with the
other tissues. And since this growth has nothing in
common with the crystallisation or successive deposition
of minerals, we are forced to allow that this manifestation
is of necessity comprehended in our idea of life.

Kiitzing, therefore, when speaking of Diatomese, ought
to have dwelt upon the fact that in these beings silica
exceeds the other material elements, and he ought only to
have instituted a comparison betweeu the proportion of this
substance, and that which is elsewhere met with among
the other material combination s proper to organic beings
and at the same time common to them with minerals.
Perhaps he would have shrunk from this comparison, for
the more the second prevail over the first, the less is the
manifestation of life. But we are not endeavouring in
this place to learn whether a being is more or less easy
to be distinguished. A serpent coiled up and an eagle
circling the heavens are certainly different in their mani-
festation of life, but the one and the other is equally
different from a stone. Where life ceases, death takes
place ; for these, being opposite states, admit of no tran-
sition.

The other opinion of Kiitzing, which, though foreign
to our present subject, we feel bound to oppose, is the
one which suggested to him the tlicory of two vitalities
combined together in equilibrio or in inequilibrio. The

350

ANIMAL NATURE OF DI ATOME.®.

same being, he says, may pass from the animal to the
vegetable nature, or from the latter to the form er, and
again return to its original state. This opinion is not
new, for it was previously held by Agardh, by Gaillon,
and by Bory St. Vincent; bnt the facts which lead
Kützing to adopt it are so precise and so well described,
that tliey do not admit the easy Charge of incorrect
observation, by which many liave hitlierto been satisfied
to answer arguments deduced from similar facts. He
sees microscopic beings corresponding exactly with the
descriptions and figures given by Ehrenberg, furnished
with organic peculiarities, and presen ting vital phenomena
gcnerally regarded by Ehrenberg and otliers as characters
of animal life, assume in their successive and natural
development, form, Organisation, and life, such as are
gcnerally attributed to plants. And from these plants
he sees reproductive bodics generated, similar to the
seeds of snperior and spores of inferior plants, eqnally
endowed with characters of animality, becoming, however,
subordinated to those of vegetable life. The fact is true,
and may be easily verified by any one in the habit of
making microscopic observations. And the explanation of
this fact appears to me equally easy. If there are beings
which, wlien tliey attain their perfect development, prove
themsclves to be decidedly vegetable, although durin g
the first portion of their existence they presented some
phenomena of animal nature, this proves that those phe-
nomena do not exclusively belong to animals, and that
we cannot draw from them absolute characters of animal
nature. The imperfection, which we have already shown
to be inherent in every notion we can form of the animal
or vegetable kingdom, begins to diminish after such
eonsiderations, and it is under this point of view that we
purpose to undertake the examination of Diatomese,
carefully separating in the characters they present,
those which they hold in common with vegetables from
those in common with animals, and inquiring if they do
not possess some exclusively with one or the other which

ANIMAL NATURE OF DIATOMEjE.

351

may decide the question. The comparison of animals
with vegetables has beeil treated and discussed in all its
forms so many times, and by so many celebrated authors,
that the mere mention of it may excite a fear that we
are about to recite things antiquated or stale, or at least
well known by every one. Therefore I shall abstain
from the useless display of cheap erudition, and shall
apply myself solely to the most recent results of scientific
investigation.

The most certain manifestations of animal life are those
of sensibility and motion, either of the whole body or of
its various parts. It is useless to enter into minute par-
ticulars in order to prove that the word sensibility, like
all other abstract terms, is merely a name by which we
understand a dass of phenomena whose cause is unknown.
Hence the abstract expression has come to denote the
cause itself, and by conventional agreement we say that
sensibility causes the phenomena of Sensation. It is
Sensation only that really exists, for that is a change that
we have experienced. Analogy leads us to conjecture,
according to certain indications, that similar changes
occur in all other animals, and, therefore, that there is a
property common in all these beings, which we call
sensibility. We see that in many cases these indications
become so transient that we are entitled to attribute
their apparent absence to the imperfection of our means
of observation.

With respect to motion, since it manifests itself
objectively, and this its manifestation is always induced
directly or indirectly by external causes, the distinction
between vegetable and animal motion has been sug-
gested to our minds, not by the action itself, but rather
by the quality of those beings hitherto regarded as plants
or animals on other grounds. And if we wish to find
elements of distinction in the phenomenon itself, we look
for them in the connection between external stimulants
and the motion produced, as also in the instruments by
which it is effected. We endeavour to prove that in

352

ANIMAL NATURE OF UI ATOM E/E.

plants all movements are determined by the pliysical or
Chemical influence of external agents. In animals, on
the other hand, the laws of inorganic nature are not suf-
ficient to explain the connection (otherwise more mediate
and remote) between the external impression and the
organic movement. Which distinction, besides being
relative to the degree of our knowledge, has, moreover,
a value limited entirely to the coarser phenomena, not
being applicable to those of nutrition and growth ; forall
these are accomplished by determinate movements that
cannot be explained by merely pliysical and Chemical
laws. “ If nature/’ exclaims Humboldt, “ had endowed
us with microscopic powers of sight, and if the integu-
ments of plants were transparent, the vegetable kingdom
would by no means present that aspect of immobility and
repose under which it appears to our senses.” And the
same may be said of the instruments ; for the muscles of
higher animals very soon disappear when we examine
more simple or smaller animals, nor certainly can we
deny animality to those minute Infusoria in which we
are unable to distinguish either muscles or any other
distinct Organs.

Having then ascertained the insufficiency of these two
principal characters, it became necessary to look for
others, not in the simple manifcstations of a supposed
subjective property, but in the objective qualities them-
selves. And these not in their external form, for we
know not the limits of its variety, but in the internal
Organisation, in the state of the more remote organic
elements, in their origin and form ation, orin the Chemical
materials of which they are constituted. This difficult
inquiry is assisted by recent discoveries, through which
Science is now put in possession of a most important
truth, — that within the superior organic type, as well
in the vegetable as in the animal kingdom, there is
included, so to speak, in a summary manner, the history
of the lower, which present in a permanent form their
various intermediate States : that the same liistological and

ANIMAL NATURE OE DI ATOME JE.

353

morphological facts wliich appear manifest in the more
simple organisms, are repeated in the more complicated ;
that the primitive organic structure is very similar in the
two kingdoms ; in short, that in the first instance every
plant, every animal, and every tissue in the one or the
other, proceeds solely from cells. And since the primi-
tive state, wliich in snperior beings is only transitory,
remains permanent in the inferior, we have thus, as well
in plants as in animals, very simple beings, reduced
indeed to the simplicity of a single cell. We do not
liere inquire whether we have viscera, Systems, tissues, on
the one hand, or roots, leaves, flowers, or even fronds or
spores, on the other ; the difference we are endeavouring
to determine is in the primitive cell, that cell which
represents the ovum or the spore as transitory beings, or
the Protococcus and the Gregarina as permanent beings.
The fiekl is open, and its boundaries are well defined.
The vegetable cell on one part, and the animal cell on
the other, but both alike in tlieir first origin, in their
formation, in every successive change.

If a dangerous rock present itself here, and if we
cannot steer entirely clear of it, we ought at least to
point it out in order to prevent shipwreck. The means
by which we endeavour to augment the power of our
senses have a limit. The microscope reveals the presence
of a corpuscle only the iOO,OOOth of a millimetre in
size ; yet, since tliis corpuscle may be large in comparison
with those which entirely elude our vision, can we ever
boast that we are able to perceive the internal structure
even of larger bodies than this ? Hcnce there is alwa}7s
great danger of believing that to be simple which in
reality only seems to be so, and which the wonderful
art.ifice of Organisation may conceal from our eyes by its
transparency, or by the compact nature of its parts.
Since the impossibility of penetrating dceper into struc-
ture is inherent in the means we resort to for the purpose,
we may still avail ourselves of comparison as a guide,
deducing nothing from observation beyond what is com-

23

354 ANIMAL NATURE. OF DIATOMEJE.

parative. But the greater peril lies in the very nature of
the subject ; because two bodies, very different in degree .
of organic simplicity, may appear very similar to each
other in our eyes, thongh armed with great magnifying
powers. And since we are novv strictly endeavouring to
discover the characters of an element, which in respect
to us is more simple tlian any other, it is to be feared
that in some cases we may take some more complex
thing for a cell.

Every organic being, if observed at the first instant of
its appearance, presents itself as a simple cell. When-
ever we have a cell before our eyes, this cell is either the
rudiment of an ulterior organism, or it is capable of
existing by itself and remaining permancntly in the same
condition, or it is an elcmentary part of some organic
tissue from which it has been separated. Every thing
anterior to the appearance of the cell, considered in its
general condition, may, in the actual state of our knovv-
ledge, be considered as still uncertain, or not fully
demonstrated ; and therefore it is that we take our
starting point from the already beautiful and well-formed
cell, because it is always identical in respect to its prin-
ci[>al characters. Its external coating solid, quite con-
tinuous, transparent, without any indication of particular
structure, viz., without a heterogeneous disposition of
molecules. The contained substance liquid, solid or
gaseous, different from what remains outside the cell.
Nucleus adhering to the inner surface, or detached within
the cavity. Nucleolus within the nucleus, distinct by a
different refraction of light or by colour, or by a different
appearance under Chemical reagents. Another general
fact, common to all living cells, is an incessant mutual
interchange of materials between the fluid within and that
external to the cell, through the solid tegument of the
cell itself causing perpetual variations in the quantity
and quality of the former.

So far the conditions are common to the two or-
ganic kingdoms. We will now compare together such

ANIMAL NATURE OF DIATOMEiE.

355

elementaryor primordial cells taken from beings respecting
whose animal or vegetable nature there can be no doubt.
If both these be subjected to the action of Chemical
reagents, they manifest different results ; hence we are
led to conclude that there exists a difference in their
chemical composition.

It is useless to insist upon this mode of chemical
reasoning; it may suffice here to quote the results of
chemical researches. The nucleus is composed of a
quarternary azotised substance (0. H. C. A.) ; this applies
equally to an animal and a vegetable cell. The solid
tegument, again, of the animal cell is always a com-
bination of proteine with water, i. e. a quaternary azotised
substance also. (C.40 H.62 O.12 A.5) ; whilst that of the
vegetable cell always consists of an unazotised ternary
substance, isomeric with starch (C.24 H.20 O.10). The
contained liquid, also, is always ternary, unazotised in the
vegetable cell, quaternary and azotised in the animal. The
included solid substances are promiscuously ternary or
quaternary ; the former prevailing more in vegetables, the
latter in animals ; and among the former, Chlorophyll (?)
starch, and gum are found exclusively in the vegetable
cell. Chemical reagents, too, disclose an essential pecu-
liarity in the vegetable cell. An extremely fine, thin
membrane, granulär in structure, of a quaternary azotised
composition, like that of the nucleus, lines the inner wall,
and hence immediately surrounds all the contents of the
cell, including the nucleus, with which, in most instances,
it is in direct continuity. This fine membrane is so thin,
and adheres so closely to the inner wall, that, in Order to
perceive it, we must resort to physical or chemical agents
to detach it. It exists in every cell, and precedes the
formation of the wall; if it seem to be absent in any
case, the reason is that in most instances it soon
disappears.

These are positive facts; and in most instances the
experiments by which they are confirmed admit neither
contradiction nor doubt. But in the special case of a

356

ANIMAL NATURE OF DIA'L'OMEyE.

cell respecting which we have to clecide whether it belong
to one ldngdom or tlie other, the Chemical test is reduced
to data so precarious as 110t to afford the same certainty.
If the wall of a cell treated with iodine be, as well as the
nucleus, colouredbrown, we maypronoimce it to contain
azote, and to be formed of a quaternary material. If,
again, treated with sulplniric acid, and subsequently with
iodine, it assumes a violet colour, there can be no doubt
of its beingisomeric with starch, since it has been changed
into that substance. But if these trials fail or prove
uncertain, as very offen happens, we must of necessity
suspend our judgment. With respect to the contained
substance, besides the promiscuous character of some
materials already mentioned, some also which are exclu-
sive, as, for instance, Chlorophyll or starch, may lead to
errors. The stomachs of a Polygastric Infusorium may
be fillcd with these vegetable substances, and tlieir
transparency and minute size may cause them to appear
very simple.

The successive changes in a cell furnish other very im-
portant characters to distinguish the two kingdoms, but
give rise, at the same time, to new and grave clifficulties.
Its extension, the excess of one diameter over the other,
the variety of forms it can assume, are frequent conditions.
rI'he disappearance and reabsorption of the nucleus occur
in every cell at some period of its existence ; but in the
cells of higher plants the fine inner membrane or primor-
dial utricle soon disappears. Here is a difficulty as to
distinction to be overcome. This remains permanent,
particularly in the Algm, if not in all inferior plants. The
enlargement of the wall, which in the animal cell takes place
in a homogeneous manner, is effected in the plant by the
deposition on its inner surface of successive strata, con-
tinuously or variously formed into circles, spiral bands, or
other intermediate forms, yet ofa ternary substance, and
varying little from that before mentioned (C.34 II. 24 O.10).
These are produced at a much later period, and then only
in the cells form part of a complicated t.issue. Then the

ANIMAL NATURE OP DI ATOM EJ&.

357

wall is not only enlarged, but successively irapregnated
with various substances, as lignine (C.12 H.16 Ö.8), with
carbonate of lime, with silica, or, finally, with a quaternary
azotised substance, as constantly happens in a portion of
the superior wall of the epidennal cells which forms the
so-called euticle, and in the thick cellular wall of marine
Confervse. Thus the elongation effected in animal cells,
on their nuclei and on their nucleole passing into distinct
fibres, has only a remote counterpart in the liber cells of
plants, in the hypothalline tissue ofLichens, in the so called
seminal threads of Charae and Musci, and in some modifi-
cations of Kützing’s amylide cells. But these fibres,
so distinct in the superior animals, and in many of
the inferior, as in Sponges, for example, entirely elude
observation when we examine microscopic beings.

In animals, as well as in plants, new cells are
organised in the interior of their predecessors ; but in
vegetables the formation of the cells always seems to be
endogenous ; in animals, on the other hand, it takes
place perhaps usually in the extra cellular fluid. The
multiplication of vegetable cells is proved to occur in
three modes.

1 . Many nuclei appear floating together with granules
of a different nature. Around each of these collects a
minute vesicle, which snccessively increases, compresses
the whole of them, and, along with them, terminates by
filling the maternal cell, which, softening and liquefying,
is finally absorbed and disappears.

2. The internal substance of the cell divides into
two or four portions, which, from their origin, are seen
to be surrounded by a distinct primitive fine membrane
and each to be furnished with its respective nucleus,
whilst the primitive nucleus and membrane of the ma-
ternal cell disappear. And, consequently, only one or
two diaphragms divide the cavity among them, and,
by detaching themselves, constitute the walls of the new
cells.

3. In the third mode of cellular multiplication it is

358

ANIMAL NATURE OF DIATOMEiE.

the wall itself of the maternal cell that, by inflecting itself
into an annular fold, constricts tbe fine primitive mem-
brane, whicli in such a case is persistent, and divides it
into two portions, so that on arriving at the centre, it
completes the diaphragm.

In the animals tliere have hitherto only been observed
with exactness the first two modes of endogenous forma-
tion of cells.

If now we descend from the comparative examination
of the vegetable and animal cell, considered generally, to
the special examination of the more simple organisms
among vegetables, exclnding all tliose that can be con-
sidered of an ambiguous nature, we shall find almost
countless n umbers which present in perfect clearness,
and in thcir primitive as well as in their permanent state,
the most simple condition of a cell and its successive
changcs.

Among animals, on the other hand, we certainly have,
as a primordial and transitory state, the egg or ovum,
especially in the lower animals, which are very convenient,
for observation ; bat as repräsentatives of their permanent
state reduced to its extreme simplicity, we possess solely
the gen us Gregcirina , of which we know six distinct
species, all of them Entozoa, all organised as simple cells,
but endowed at the same time with contractility and
expansibility quite sufficiently to put their animal nature
beyond doubt. For, when we considcr the more simple
Infusoria, the Monacles, the Vibriones, and Faramecia,
we soon perceive that their simplicity is apparent only.
In respect to tliese (Monades, &c.) we have not to take
merely account of properties inherent in a simple cell,
but must ratlier seek to estimate those which belong to
tissues wliose organ ic elements escape our sight. Che-
mical reagents exert only a complex action upon the
entire material of the body, whence we suppose it to
be principally constituted of an azotised substance.
And here I dwell upon the peculiarities of such Infusoria ;
for if, on one hand, they denote an Organisation far more

ANIMAL NATURE OE 1)1 ATOM EiE.

359

complicated than what was formerly ascribecl to tlicse,
they may, 011 tlie other, claim to represent tlic ordinary
conditions of the elementary cell.

Ehrenberg has described and delineated in many so-
called Polygastric Infusoria, a mouth and anns, many
vesicular stomachs, secerning glands representing the
masculine sex, and ovaries along with these, together
with one or more eyes in very many. The existence of
such organs, in certain species, seems to be a fact now
placed beyond controversy and beyond doubt. But the
criterion by which the organs themselves are judged by
aualogy to exist in other microscopic beings, are not
equally certain. Thus in the Closteria, and generally in
all the Desmidiese, it is clear that Ehrenberg is egregiously
inist alten.

He supposed to be a stomach the nucleus, which, in
Closteria , as in Zygnemata, is, from the first, suspended
in the middle of the cell, and is large, transparent and
colouiiess : but in order that these might systematically
be termed Polygastric Infusoria, he applied the names
of stomach and spermatic glands promiscuously to grains
of starch and gonidia in their different states of develop-
ment. Chlorophyll and all the rest of their contents he
arbitrarily represented as ovaries.

The introduction of a coloured substance, accomplished
only once in a Closterium , and only into one of the
vesicles situated at the two extremities, proves no more
than this, that the supposed terminal apertures may
ready be found in certain species at certain periods of
their existence. And we know that in vegetable cells,
at certain periods, there are formed in certain parts of the
plant, circumscribed and regulär apertures through
which the contents issue forth. The mere presence of
an aperture, and the introduction of exterior solid sub-
stances through this opening, cannot, therefore, be an
absolute character of aniraality ; for this, like other cha-
racters, is only of value as it is in accordance with the

360

ANIMAL NATURE OF DI ATOME JE.

general conditions of organic beings. Having observed
the presence of eyes in Infusoria we fortbwith proclaim
as eyes every red opaque spot, not raerely in Infusorial
Animalcules but in all microscopic objects, and tlie pre-
sence of eyes is adduced as an incontestable proof of
their animal nature. The observations of Kützing,
already quoted, on the metamorphoses of Microglena
monadina into ülot/irix zonata, and of Cryptomonas
pulvisculüs into Stigeoclonium stellare , clearly show that
elementary vegetables may not only manifest an appa-
rent movement bnt may also present a body similar to
the so-called eye in Infusoria, and the last is probably
nothing more than a cell-nucleus.

Finally the division into two equal parts, or as we
term it the deduplication, may take place in a being
of complex Organisation in a mode apparently similar
to that by which it is effected in a simple cell. Not
only in the lower Infusoria, as Monades and Vibriones,
but in Polypi also, we see a transparent area appcar first,
and subsequently a line of dcmarcation in the place
where a true division is effected at a later period.

Having premised these general considerations, let us
examine the Diatomeae, availing ourselves of the special
and often cited labours of Ehrenberg and Kützing, as
well as of scattered observations by other authors, and
adding to these the result of our own researches.

Every Hiatomean is formed of a siliceous shield and a
soft substance therein contained. Accordingto Kützing,
this shield consists of pure silica, or, in some cases,
perhaps, of silica combined with alumina. Nägeli, further,
says that the silica is deposited in the outside of an
organic membrane, which he believes to be of a vegetable
nature. In fact, an organic membrane ought to exist,
for the silica could not becorae solid except by crys-
tallising or depositing itself on some pre-existing sub-
stance. On the other liand, we cannot admit, with
Nägeli, that it has been deposited externally ; for in

ANIMAL NATURE OE DIATOME/E.

361

many genera, and especially in the Achnanthidia , the
siliceons shield is covered with a very delicate dilatable
membrane, itself containing silica, as is proved by its
sustaining nnchanged the action of fire and acids. There-
fore, comparing this shield with other organic formations,
whether animal or vegetable, containing, in like manner,
either silica or some other so-called mineral element, we
may reasonably consider it to be formed of an organic
tissue permeated by silica. This permeation may occur
either in the wall of a simple cell, as is seen in the
epidermal cells of many plants, or within minute cells, as
in various plants and animals. The action of heat or of
acid, in these cases, destroying the organic matter and
leaving the silica nntouched, does not alter the ap-
parent form of the organ, because the skeleton remains
unaltered.

Externally to the shield, Kützing observed a thin
stratum, which he denominated cement , which may be
made visible either by desiccation or by calcination, and
produces either a simple opacity, or lines, points, and
maculae, sometimes irregularly disposed, sometimes regu-
larly. He supposes it to be a silicate of iron or of alumina.
Independently of the Chemical materials which it may
contain, this outside integument seems to me the more
important inasmuch as even without resorting to the
means indicated by Kützing, I observe it to be constant,
not merely in the species enumerated by him, but also
in many others, and I could almost assert that it exists
in all. For to me it appears to correspond with that fine
membrane of the Achnanthidia above mentioned, which,
according to Kützing’s own observations, is always
visible whenever the two new individuals, (into which
every Diatomean is resolved in its multiplication by de-
duplication) ( sdoppiamento ) begin to separate. The
lines and points snpposed to belong to the subjacent
shield belong very frequently to this kind of covering.

The shield itself is formed of at least four pieces, or
valves, united together in a four-sided figure — tctragon.

362 ANIMAL NATURE OE DIATOMER3.

The mode of union is unknovvn. But the existence of
a kind of articulation xvliich permits an opening and
closing, like the valves of a shell-fish, described by Corda
in a species of Surirella, has been denied by other
observers. Be this as it may, whether spontaneons after
deatli, or induced by external means, this Separation
does take place in a regulär manner. Now, if we sup-
pose an organic cell witli a wall permeated by silica, and
witli a four-sided figure, we can easily suppose tliat all
the sides will mechanically snpport each other. More-
over, we shall mect witli numerons facts by a different
kind of analogy, viz., tliat witli solid animal tissues belong-
ing eitlier to the internal skeleton or the external tegu-
ment.

The four valves are eqnal in lengtli, but in many
species and genera one pair exceeds the opposite pair in
breadth. In ordcr to establish an uniform language it is
convcnient to term tliose primary valves or surfaces
which exhibit along the middle the line of division in
the actof deduplication, which, sinceit is formed liere in a
normal manner, runs parallel to the other two surfaces,
dcnominated lateral. Along the primary surfaces we
frequently sce longitudinal lincs, which terminate at the
two extremities in small apertures. Brom their internal
surface there project into the cavity linear marks vari-
ously formed but always longitudinal ; these are termed
vittce.

The lateral surfaces have frequently a round aperture,
of greater or smaller size, in the centre, and from this a
fissure extends towards each extremity. This fissure
eitlier loses itself gradually, or expauds into the regulär
terminal apertures. Wlien this occurs, each of these
surfaces is divided into two distinct valves. On these
lateral surfaces we observe the strise, lines, and trans-
verse costse, no less admirable for their beautiful appear-
ance tlian for their constant regularity in number,
direction, and proportion. When many individuals are
united together to form one compound being, like a polyp,

ANIMAL NATURE OF DIATOME/E.

363

for instance, it is always by tlie lateral surfaces tbat they
toucli each other ; ancl since all other cliaracters some-
times fail, we can affix to them the denomination lateral
from this principal one.

Besides the vittae before mentioned, in some genera
{Biddidphia, Clemacosphenia, Terpsinoe ) there are other
solid snbstances in their internal cavities ; these are
variously arranged.

These essential peculiarities of the shield may perhaps
be regarded as indicating a complex structure, very
different, therefore, from what would be prescribed by a
simple cellular wall. Ehrenberg deduces from it an
argument to compare it with the shell of Mollusca.
The Arcellinse may be cited among the Infusoria.
Kützing states, in reply, that among vegetable cells
there is found a peculiar conformation of the walls, with
prominences, depressious, points, lines, papillae, and
perforations, disposed in a regulär mann er ; he refers
to grains of pollen, as an instance. He might have
added the more appropriate instance of the Desmidiese,
which would be very closely allied to tlie Diatomeae,
if the latter, like the former, could be referred to the
vegetable kingdom. If not equal in constancy and
regularity, the Desmideae display a greater degree of
complication ; and we must remember the different
nature of their substance, for in the vegetable cell, when
lime or silica predominates, the wall becomes uniform and
regulär (?) (in the text uniforme ed «Vregolare.)

The soft internal substance is brownish yellow, or of
a gold colour. It is so described by Kützing. At first
it is almost always homogeneous ; at a later period it be-
comes granulär, and divides into lobes, or contracts into
many spherical bodies, or only into one larger globule.
The development, forms, and distribution vary in different
groups, but are characteristic in the greater number of
these. Usually at first there is formed a continuous
membrane, which afterwards splits longitudinally, and at

364

ANIMAL NATURE OE DIATOMEiE.

a later period transversely, forming föur lobes, whicli at
a later period divide into minor portions. Iience Kützing
infers that tliis substance corresponds with the gonimic
matter of Conferva? and Algae in general. And' lie ad-
duces, as a principal argument, that by means of alcohol
he can extract from the Diatomea3 a colouring matter
similar to Chlorophyll.

There exist, besides, among tliis substance, minute,
colourless, and transparent splierical globnles, varying, in
the same species, in nuinber, size, and disposition, at
different stages, and we may add, aceording to various
conditions, even under the eye of the observer. Kützing
describes them as oil globales, becanse he saw them run
one into another, as well on the inside as the outside of
the sliield. And he adds that these oil globnles, in
appearance and position, exactly resemble grains of
starcli in otlier Algm, for wliich they seem to be sub-
stitutes, as happens in the cotyledons of Cruciferae.
The oil globales of Kützing are regarded by Ehrenberg
as glands representing the male sex, and the supposed
gonimic substance he tliinks belongs entirely to the
ovaries.

Einally, among the various bodies whicli constitute the
internal substance of Diatomeae, we have to mention
some globnles ( globelli ), more or less numerous, wliich
are found disposed eitlier in transverse arches ( archi ),
round the median aperture of one lateral surface, but in
very few species. These Ehrenberg regarded as stomachs,
being led to that opinion by seeing them coloured with
indigo — an effect, however, that could only be produced
by keeping the Diatomeae a long time in water laden with
tliis colouring matter, and often renewed. Kützing be-
lieves tliis circumstance sufficient to show that they are not
to be deemed gastric sacs, but merely solid corpuscles,
wliich, being situate nearan opening, exerted an especial
attraction upon the colouring matter. lie makes no other
remark on their nature.

ANIMAL NATURE OF DIATOMEiE.

365

Whilst unable to confirm or refute the opinions of
Ehrenberg, we seem to have observed facts sufficient to
disprove tliose of Kützing. First, besides the three sub-
stances or bodies of a different nature described by this
author (the gonimic matter, the oil globules, and the
presumed stomachs of Ehrenberg), we observe in all
species wlien examined alive, and in many after death, a
colourless substance, mostly extended in the form of a
membrane, and which seems to stand in continuity with
the remaining contents. Indeed Corda observed and
figured it, and Ehrenberg, as well as Kützing himself,
makes frequent mention of it in his descriptions. I
dare not assert anything as to the nature and functions
of this fine membrane ; but I do assert, notwithstanding,
that in its appearance, in its form, and its behaviour
under the action of Chemical reagents, it differs from the
thin membrane or primordial utricle of the vegetable
cell, to which it might be compared.

With respect to the so-called gonimic substance, its
identity with the endochrome of the Algse is not at all
proved. Its colour is different, and it is differently
coloured by Chemical reagents. The resemblance to it in
some instances, as in Melosira, in regard to conforma-
tion and successive alterations, is only in appearance. In
the endochrome of Algse the monogonimic substance
begins by presenting a granulär appearance, then it be-
comes distinctly granulated, and changes into the poly-
gonimic substance so minutely described by Kützing.
But these changes do not occur in the coloured substance
of Diatomese. If we insist upon a parallel, we can only
compare it to the cryptogonomic ( crittogonomica ) sub-
stance of ßyssoidia, Callithamnia, Grißthsia, and Poly-
siphonia. It divides into parts, which successively un-
dergo ulterior division. And in regard to these changes,
we may observe that there is an essential distinction
between those that occur during life and tliose that take
place after death, the greater number happening in the
latter condition. And, during life, besides the changes

366 ANIMAL NATURE OF DIATOMEiE.

detected on comparing individuals of the same species,
tliose which take place under direct observation merit
particular mention. Tlie lobes described by Kiitzing are
seen to swell, and in some places to project and retract
successively.

The identity of tliis snbstance with endochrome is con-
tradicted by Kiitzing’s own experiments, which will be
found very exact, by any one who may repeat them.
These prove it to be very rieh in nitrogen ; it emits
ammonia copiously when decomposed by heat, and this
can only proceed from a substance abonnding with it,
which such a deconi position compels to yield it up. Nor,
on the contrary, do I believe that there is any weight in
the arguraent from the solubility of its colouring principle
in alcohol, for this is not a property peculiar to Chloro-
phyll or to any snbstance of vegetable origin. Finally, I
may add that if a portion of Chlorophyll could be demon-
strated in the interior of Diatomeae, this would by no
mcans invalidate their animal nature ; we niiglit still
suppose that they had swallowed it for food.

As to the oil globulcs, I fully agree with Kiitzing
that they have this appearance ; for some of them liquefy,
possess a high refractive power, and may be artificially
squeezed out, so to speak. Without any discussion of
the instances in which oily substances are met with in
vegetable cclls, I argue that they are equally present in
the two kingdoins. For, I ask any one habituated to
the use of the microscope and to observations on In-
fusoria, whether the presen ce of globulcs of an oily ap-
pearance be not a constant fact, not merely in minute
animalcules, but in almost every portion of animal sub-
stance P The so-called Sarcode of the French micro-
scopists assumes, in fact, the form of oil globules. I
observe, too, that the number and volume of these
globules increase considerably after deatli, and that
during life they are situated upon a longitudinal line
extending from one extremity to the other. And I rely
upon the observation that there is some motion and suc-

ANIMAL NATURE OE DIATOMEjE. 367

cessive alteration in them, as if these minute globules
mixed themselves with larger ones, ancl separated again
from them.

Finally, with reference to the snpposed stomachs of
Ehrenberg, hitherto no fact enables me to satisfy myself.
I will only remark that, exactly in the median region of
JVaviculce, corresponding to the large aperture, the mem-
branous production before mentioned may be seen ex-
tended across, during life; and this, vanishing after
death, leaves in its stead an ample transparent area, of
circular figure, and snrrounded by those granules that
take colour with indigo.

We will now continue the analysis of Kützing’s
anatomical and physiological observations. All the
Diatomese, he says, give out tlirough their apertures a
mucous substance, which he calls jelly, to identify it
with the vegetable jelly; this either diffuses itself in
water, or collects into varions shapes, or contains entire
and determinate simple or multiple series of Navicultß,
forming one or more gelatinous tubes, which, detached
or connected into bancls, assume the form of the Phycoma
of true Algso. I confess that I have no arguments to
controvert the foregoing indication of the origin and
formation of the peduncles in Achnanthese, Gompho-
nemeae, and Ulnariae ; but to any one who has observed
these beings, the explanation will not be satisfactory at
all. It would be more probable to suppose that this
peduncle should represent the original cell within which
the siliceous frustules were successively developed. We
might again make this supposition in respect to the
gelatinous tubes containing the Naviculse of Schizonema,
Micromega , and other alliecl genera. But be it a simple
product of secretion, or of itself an organic portion, this
substance may ecpially belong to an animal and to a
vegetable. Kiitzing declares it to be a gelatinous sub-
stance, or isomeric with starch ; but adduces no experi-
ment to prove it. The trials I have madc seem to indi-
cate a ternary non-azotised composition ; for wlien burned.

3(58 ANIMAL NATURE OF DI ATOM13J3.

it lias not the odour of liorn, but of aniseed, and the
products of distillation have rather an acid than an alka-
line reaction.

According to Kützing, the propagation or multiplica-
tion of Diatomeae takes place in three modes ; by deve-
lopment of the gonimic substance, by division, and by
formations analogous to seeds or gemmules.

The first is merely suppositious, and therefore requires
no further notice.

Division is always longitudinal, and takes place under-
neath a fine externa! siliceous membrane, by the formation
of contiguous diaphragm-walls whicli divide the internal
cavity. Thus the contents are longitudinally divided.
And this division is complete if the two new individuals
detach tliemselves, and so acquire individual liberty. It
is imperfect if the fine siliceous persistent membrane, and
the sccreted gelatinous substance retain them collected
together. This mode of reproduction, (whicli Brebisson
distinguished by the name of duplication and deduplica-
tion from the reduplication of Desmidieae,) deserves the
most attentive observation. The foregoing exposition
presents the fact in its most rüde and superficial general
appearance, and makes us feel acutely the want ofa more
circumstantial description peculiar to various forms. It
is only after having established facts relative at least to
the principal generic types, that we can establish, on a
scientific basis, the general idea of multiplication by dupli-
cation. A few observation s suffice, however, to prove
that this does not occur in so simple a manner as we are
taught to believe by comparing it with that in vegetable
cells.

In the Achnanthidia, for example, it is described and
figured that the principal surfaces, which occupy the
intermediate space between the two superior and the
inferior valves, commence by presenting fine transverse
lines, and next a strong longitudinal line along the
middle ; then there appear two new intermediate valves
contiguous to each other, the superior (valve ?) of the

ANIMAL NATURF, OF DIATOMEvE.

369

new inferior individual, and the inferior one of the
superior. My observations convince me tliat the affair
does not proceed with so much simplicity. I have
often seen the two lateral valves separated, and the
intermediate space thus largely araplified. In other
cases there appeared only a new inferior valve com-
plementary to the superior, the inferior individual thus
remaining incoraplete. Finally, in others, between
the complete superior individual and the incoraplete
inferior valve, there appeared a new individual, with
both its valves ; but nearer together, smaller, finer, with
lines much less distinct. The exact exposition of this
and other observations relating to it, will form the sub-
ject of another Meraoir. It may suffice for me to inti-
raate here just enough to demonstrate, that in this phe-
nomenon there is more complication than that of a
simple cellular deduplication (sdoppiamento.)

The third mode of reproduction discovered by Kützing,
and that upon which he founds his principal argument
in support of the vegetable nature of Diatomese, is coin-
parable, he says, to the formation of spores or of buds
\gemmce) in plants. The Melosirce consist of globular-
shaped individuals united together by means of a fine
external siliceous permanent membrane, into a filiform
series, in a manner perfectly similar to the articulations
of a Conferva. Each of these consists of two principal
valves, in form like two sections of a sphere or polyhe-
dron, inserted upon a cylindrical wall, by means of
which the two valves or principal surfaces are united
together and continuous. Kützing saw some of these
presumed articulations to be dilated, as also occurs
in those which contain the spores of C Edoqonia .
lhough he observed nothing more, this was sufh-
cient for him to declare as a fact the propagation by
spores.

The other fact has reference to those Naviculae which
have a simple or multiple sheath, constituted of what
he states to be a gelatinous substance Consolidated into

24

370 ANIMAL NATURE OE DlATOMEjE.

tlie form of phycoma. In some species of Schizo?iema
and Micromega, he found contained within tlie same
substance, globular bodies, whicli lie saw successively
enveloped in new phycoma, whilst tlie included sub-
stance, at first minutely granulär, grew into so many
Naviculac. The observation is valuable, and furnishes a
very important subject for study. Tor, whilst in other
cases the difficulty of keeping pace witli tlie successive
development of the same individual obliges us to observe
comparatively, different individuals, in respect of which
there may always exist a doubt whether tliey really
belong to the same species, here we liave, as it were,
a wliole brood, consisting of individuals which pre-
sent, at the same time, all the pliases of tlieir de-
velopment. And this expression of (covey or) brood
is not licre used at random ; since no direct argument
beyond that from external rcsemblance, tends to sliow
that these rcproductive bodies are true spores ; whilst,
in the animal kingdom we find equally numerous analo-
gies, as well in the ovaries of Polyps and other inferior
animals, as in many Ovipara of superior classes. And in
fact the bag of a spider, with the thousands of small eggs
that it contains, secms to me quite as like as the spore
of an Alga to the organ of propagation of a Schizonema
or a Micromega.

Einally, in respect to the movements of Diatomeas,
Kützing’s opinion evidently accords with ours; since,
after treating at some lengtli on the question of their
animal or vegetable natu re, he arrives at the singulär
conclusion that Diatomeee consist of tliree substances :
1, one inorganic, constituting the sliield; 2, one
organic and vegetable, constituting the internal gonimic
substance, the external envelope, and the peduncles ;
3, one organic and animal, from which are formed the
organs of motion. We cannot admit this third opinion,
inasmuch as he assigns organs of motion even to the
lower vegetables and their spores, similar to those which,
according to him, partake of something like animal life.

ANIMAL NATURE OF DI AT0ME7E.

371

Ehrenberg discovered, in some Naviculae, a distinct foot,
similar to that of Gasteropod molluscs, projecting from
the median aperture and from the fissure in tlie inferior
valve. In some Surirella, again, he observed extensible
and contractile cilia protruding and retracting through
numerous perforations in the margin. Certainly such
organs are not to be compared with the vibratile cilia
recently discovered on the surface of the vegetable beings
before mentioned. But (independently of the presence of
these organs, which hitherto have only been seen by
Ehrenberg and Corda) the motions of Diatomeae, as
admirably described by Kiitzing himself, are so different
from the motion of Oscillatorieae, Desmidieae, Proto-
coccoideae, and the spores of other Algae, that they must
certainly be referred to a different origin. Careful experi-
ments may exclude all exterior causes, from the mediatc
impulse of other bodies, from evaporation, Chemical and
other agency. There still remains aclmissible the sup-
position of currents produced by the continued inter-
change between the exterior and interior liquid. But,
with equal right we may admit the other supposition,
that in a being wliose nature, for other reasons, we
believe to be animal, the movements may be effected by
the admirable vital powers through organs which escape
our sight by their minuteness. I add that, even in the
smallest Naviculae, observed with high magnifying
powers, there is seen, during their motions, an agitation
and a kind of sparkling, or, to speak more scientifically,
a rapid and indeterminate change in refraction of light at
their extremities, precisely in the Situation of apertures
existing there in the shield. Ilence I venture to infer
that though we cannot draw an absolute proof in support
of the animal nature of these beings from their move-
ments, it is still right to bestow particular attention on
these facts.

Resuming what has been hitherto said, and comparing
the argmnents which seem to indicate the vegetable
nature of Diatomeae with those which favour their animal

372

ANIMAL NATURE OF DIATOMEiE.

nature we are of necessity led to tlie latter opinion. If
we suppose tliem to be plants, we nmst admit every
frustule, every Navicula, to be a cell. We must suppose
this cell with walls penetrated by silica, developed within
auother cell of a different nature, at least in every case
where there is a distinct peduncle or investing tube.
In tliis siliceous wall we must recognise a complication
certainly unequalled in tlie vegetable kingdom. It
would still remain to be proved that tlie eminently
nitrogenous internal substance corresponded with the
gonimic substance, and that the oil globules could take
the place of starch. Tlie multiplication would be a
simple cellular deduplication (sdqppiamento), but it would
remain to be proved that it takes place, as in other
vegetable cells, either by the formation of two distinct
primitive utricles, or by the introflection or constriction
of the wall itself. Finally, there would still remain un-
explained the external motions and the internal changes,
and we must prove Ehrenberg’s observations on the
exterior Organs of motion to be false. But, again, ad-
mitting their animal nature, much would remain to be
investigated, both in their organic structure and their vital
functions; excepting this, so far as we know, we have
only one difficulty to overcome, that of the probably
ternary, non-azotised composition of the external gela-
tinous substance of the peduncles and investing tubes.
But as the presence of nitrogen is not a positive cha-
racter of animal nature , so the absence of it is not a
proof of vegetable. And in Order that the objection should
really have some weight, it would be well to demonstrate
that this substance is isomeric with starch. For then,
supposing all the arguments in favour of the animal nature
of Diatomeae were proved by new and more circumstantial
observations, this peculiarity, if it deserve the name of
objection, might still be regarded as an important dis-
covery. We should then have in the animal, as well as
in the vegetable kingdom, a ternary substance similar to
that forming the basis of the vegetable tissue.

ANIMAL NATURE OF DIATOME/E.

373

I conclude, however, that in the actual state of
Science, the Diatomese are to be enumerated among
animals, but at the same time much remains to be
accomplished in order to disclose their intimate organh
sation and vital phenomena. In the sadness of the re-
flection we are consoled by the saying of the immortal
author of * Cosmos/ that there is a field open for great
discoveries where at present we see only scattered and
unconnected facts.

ORGANOGRAPHIC REVIEW

OF THE

GENERA OE DIATOMEiE,

15STABLISHED BY KÜTZING.

1. Epithemia. — Lorica in sectione transversali trape-
zoidca ; striai transversales validce interdum gramdatce v.
moniliformes.

The characteristic trapezoiclal figure of the transverse
section results from the circumstance tliat the two prin-
cipal surfaces are parallel to each other, whilst the lateral
oiies, again, are more or less convergent.

The superior surface is convex, the inferior concave,
but usually with a much less decided curve ; for whicli
reason they are not exactly parallel. In some species,
again, the inferior surface is plane, and the superior
strongly convex, and carried down to the lateral surface,
whencc the section, instead of being trapezoidal, proves
semicircular. Besides, the superior surface, instead of
being regularly continuous, may present prominent lon-
gitudinal costae. At least this is the case in my
Epithemia costata, whicli occurs in Dalmatia, parasitic on
j Biddtdphitt. {E. major e latere semielliptica apicibus
acutis non prominentibus, e facie elliptico elongata, dorso
lo7igitndinaliter costata, costis ad latera transverse striatis.)
This species has the form of a grain of coffee applied by
its plane surface, and furrowed ( solcato ) longitudinally
along its convex surface. It is (HMS'" long, 0*034///
broad, 0-01 T" high. And these longitudinal costae might
perhaps indicatc {accennare) an association of individuals,

ANIMAL NATURE OE D1ATOME/E.

375

such as we have in the genus Himantidium, inasmuch as
the multiplication by bisection ( dimezzamento ) occurs
precisely in that direction. In such a case we should
have both in the genus Epithemia and the Himantidia ,
incomplete division and lateral adhesion of inclividuals
in the family Eunotiese, and the first example of poly-
pariform association through adherence by one of the
primary surfaces, in this respect corresponding to
the Synedrce , with this difference only, that the latter
adhere by one extremity. Ehrenberg observed four in-
dividuals thus connected in the E. Westermanni. The
comparison is justified also by this, that in my Epithemia
there appears a kind of foot, which projects at the two
extremities, with truncated appendages.

In all Epithemia the two principal surfaces present, at
each extremity, two small apertures, united to similar
apertures in the opposite extremity by fine longitudinal
lines. The transverse strise of the lateral surfaces are
very evident, and in some species {E. ocellata, E. Aryus,)
terminate on the dorsum in round apertures. They are
furnished with cilia, according to Corcla, in his Navicula
ciliata, which to me appears to be an Epitliemia rather
than a Cocconema, as supposed by Ehrenberg (C.yibbum).
The internal substance appears to be uniformly extended
at the origin, divided subsequently into two lateral
masses ; it is brownish-yellow, or green. A series of
minute oily drops occupies the median line. Many
species live in fresh water, many in the sea, and some are
found in a fossil state. Kiitzing enumerates twenty-one
species, to which we think two others (E. costata, E.
ciliata,) ought to be added.

2. Eunotia. — “ Lorica in sectione transversali trape-
zoidea, strice transversales ienuissimce

Although the only character by which this genus is
distinguished from the preceding be the fineness of the
transverse strioc on the lateral surfaces, yet the distinction
appears to be justified by the circumstance that the

376 ANIMAL NATURE OF DIATOMEjE.

Eunotice are never found adnate and parasitic, as is con-
stantly the case with the Epithemice. They are all found
in fresli water, the greater number are exotic, many
rare. When observed laterally, they are frequently
seen to be more gibbous or prominent on the dorsum,
which proves that the prominen ces themselves are placed
transversely. Thirty-six species are enumerated by
Kützing. It would seem that he ought rather to refer
to the Eunotia formica than to the Epithemia gibba, the
Eunotia No. 6 (pl. 2, fig. 27 ab,) of Bailey, which has
very well-marked transverse striae ; and tliis uncertainty,
were there no other, renders the distinctive characters of
the two genera somewhat doubtful.

3. Himantidium. — Lorica in sectione transversali rec-
tangula ; striez transversales tenuissimee , densissimee , in-
dividua in fasciam transversaliter et arcte conjuncta.

If we could distinguish the Himantidia from the
Eunotia ? by the incomplete division, from which there
result associations or polyparies in the form of a band,
as in Odontidia and Fragillaria, there would still remain
the character of the entire family, i. e. the difference be-
tween the two primary surfaces. And since these asso-
ciations are not always numerous, as in the three typical
species (//. Soleirolii, II. Veneris, II. guganense ), we find
it to be justly remarked by Kützing, that tliis genus is
not yet well established, a remark that derives increased
value from the fact already stated, that there is a lateral
association even in the Epithemice ( Epitliemia costala,
Men.). Tliis very resemblance, however, attracts atten-
tion to another circumstance, viz. the parallelism in
the Himantidia of the lateral surfaces, which, in the
Epithemia , are essentially convergent. Of the ten
known species, four only are European ; they are all in-
habitants of fresh water.

Of the three genera now enumerated, Kützing consti-
tutes his family of Eunotieae, which only possess in com-
mon the single character of convexity in one and concavity

ANIMAL NATURE OF DIATOME/E. 377

in the otker, of tlie two principal surfaces ; a character
which reappears in various genera of stomatic Diatoraese.
Abstracting tkis cliaracter, the Himantidia would be
referable rather to the family of Fragillarieae, with which
they seem to liave a greater affinity.

4. Meridion. — Indivülua cuneiformia, prismatico-rec-
tangula, in corpuscula flabelliformia vel fascias spirales
arcte conjuncta. Stria transversales valida, pervice.

Kützing compares the Meridiese to the Gomphonemese,
which they really resemble, in the cuneate form of their
single frustules, when viewed in front. But Gompho-
nemese have a median aperture, and interrupted transverse
strise, on account of which they belong to another order.
In the order Astomaticse, the author himself quotes the
Odontidia as allied to this genus ; but the Synedrce ap-
pear to me to approach it still more nearlvj from these
the Meridia in like manner rather differ in their cuneate
form — which is inconstant, — by their ovate obtuse figure
at the one and their acute figure at the other extremity
of the lateral surfaces. The observation of M. Zinckem
on the vittse, whose presence is inconstant, becomes
very important. This fact proves, in my opinion, that
there is no foundation in truly natural characters for the
primary distinction which Kützing establishes between
the vittated and the simply striatecl Diatomese, by which
so many natural affinities are openly transgressed, and so
many forced alliances are effected, as we shall soon per-
ceive. In the scanty state of our actual knowledge re-
specting the true Organisation of these beings, it is im-
possible to establish a natural Classification of them. In
order to deviate from this as little as possible, it would
be requisite to consider all the characters collectively, as
we do in all other beings, whether animal or vegetable.
And every distinction based upon a single character, be-
sides being purely systematic, loses all value as a facility
for Classification so soon as exceptions occur, as in the
present instances. Kützing says that at first the internal

378 ANIMAL NATURE OF DIATOMR®.

substance entirely lines the inner wall of tlie shell, it
becomes divided afterwards into minute portions, which
terrainate by concentrating themselves in distinct globules.
I believe tliat these changes only occur after deatli.
Bailey succeeded in extracting a greenish resinous sub-
stance by means of alcohol. Only two well-defined
species inhabit the fresli water of all Europe ; two others
are doubtful.

5. Eumeridion. — Individua cuneiformici, prismatico-
irapezoidea (?), inflabellum vel fasciam convolutam coalita ,
demum stipitata. Stria transversales per via, validce.

As Riitzing has only seen dried specimens of the
Meridion constrictum of Ralfs, upon which he has con-
structed this genus, it secms tliat we may assert from the
cxact dcscription of this author, quoted at length by
Hassall, tliat there is no indication whatever of tliat
gelatinous pcdicel likc a cushion, upon which Kützing
asserts tliat the frustules are arranged in a fan-shape,
as in the Synedra. Perhaps this erroneous impres-
sion may be founded on Ralfs’ figurc and descrip-
tion of the dried specimen, compared witli the living
one. These are his graphic words : — “ As, however,
tliey are not arranged in a plane, as in Meridion
circulare , but stand nearly erect, somewhat like the
staves of a tub which is broader above tlian below,
wlien tliey are dry and fall down they necessarily
separate, and gaps are produced in the circular outline.
In the dried specimens I lind some of the frustules
arranged in a circle, which however exhibits the gaps
already noticed, whilst others seem to be fasciculated.”
Therefore there remain only the trapezoidal section from
the inclination of the lateral surfaces and the constriction
of these near the apex, which characters, tliough un-
doubtedly of value to discriminate species, are not suffi-
cient to establish a genus.

The superfluous division of genera, whilst it disguises
the truc affinitics of objects, and fruitlessly complicates

ANIMAL NATURE OF DI ATOMEN. 379

the study of tliem, has the additional mischief of exalting,
in some degree, the value Convention ally attached to
characters, and compels us to form a distinct family of
every genus. Such is the case with this attempt of
Kiitzing in respect to the last two genera with the name
of Meridiona, though they do not really differ from the
preceding genus Eunotia, or the following one Fragillaria ,
except by a slight modification of form. Yet a similar
modification does not seem sufficient to distinguish
the two genera Meridion and Eumeridion. In general,
characters deduced from the form of single individuals,
certainly deserve a preference in comparison with those
furnished by associations of numerous individuals into
polypariform bands ; but inasmuch as we do not know
the relation between outward figure and internal Or-
ganisation, the subdivision of families founded only upon
this character seems premature, to say the least.

6. Denticula. — Individua libera singularia vel binatim
conjuncta, a latere primario oblonga l. linearia, secondaria
transversim striata l. costata ; strice pervice , validce.

The morphological character of this genus is the pre-
dominance of the primary surfaces over the secondary,
and the continuity of striae Crossing these latter. We shall
have an opportunity of returningto this particular subject
when treating of Suriretta. At present it is sufficient
to observe, that wliilst the first five species described by
Kiitzing, and figured in plate 17 of his work, show the
greatest affinity, not merely one to another, but also with
the subsequent genus, the two others, 1). constricta and
D. undulata, display only how vague is the artifice of
this System whicli brings together objects so dissimilar,
and separates those which are truly allied. In these two
species there is not only wanting the predominance of
the primary over the secondary surfaces, but instead of
transverse striae, there are elevated costac, and in one of
tliem (ZI. undulata) even vittae are visible, as they are in
Surirella solea, to which it bears so great a rcsemblance,

380 ANIMAL NATURE OF DI ATOME AS.

and yet, notwithstanding all this, it is included in the
grand division of JDiatomece non vittatce. The narne of
any section and the character whence it is derived, need
not be constant when the section itself is founded upon
an assemblage of other characters, and its true charac-
ters consequently derived from affinity. But when this
character is isolated, it entirely loses all the systematic
value it can possibly liave, so soon as it is wanting in
constancy.

7. Odontidium. — Tndividua quadrangula , a latere
secondario transversim striata , lanceolata, in fasciam
biconvcxam arcte conjuncta.

The Odontidia are merely a filiform series of Lenticulce.
Wlhlst among the Himantidia tliere are promiscuously
enumerated species of which the individuals are conca-
tenated, and species with individuals merely geminate
(II. Arcus), here, on the contrary, two genera are distin-
guished by this character solely. And the same character
— the cuneate form of the frustules — by which the genus
Meridion is distinguished from Ilimantidium , is again
met with in Odontidium, but inconstantly and irregularly.

I do not wish to infer from this that tliese generic dis-
tinctions may not be appropriate, because in the paucity
of our knowledge respecting the intimate Organisation of
these beings, tliere is no adecpiate support for this opinion
or the contrary ; but it seems to me a clear inference that
in an organological point of view these characters possess
little value. Then, the number of transverse strise varies in
the same species, probably according to age. Six spe-
cies inhabit fresh waters, principally alpine, one only (0.
syriacuni) inhabits the sea, one (OP glans) is found
fossil, and one (Fragittaria grandis, Ehr.) is uncertain,
to which, as an uncertain species, we may add the Syrinx
annulata of Corda, which, if the figure ( ‘ Ahn. Carlsb.,’
1833, tab. iv, figs. 45, 46,) be correct, has the singulär
character of continuity of the transverse striac e.ven over
the primary surfaces.

ANIMAL NATURE OF DI ATOMEN.

381

8. Fragillaria. — Individua linearia lavissima sym-
rnetrice formata, in fascias vel rectas vel curvas, bicon-
vexas, arcte conjuncta.

The singulär individuals which constitute the filiform
aggregations of Fragillarice, are so like Naviculee that
there is often a doubt whether a particular species should
be referred to the Fragillarice or to the genus Diadesmis ,
in which the filamentsare formed of Naviculse possessing
the essential character of a median aperture in the lateral
surfaces. In fact, this doubt pervades all the new species
enumerated by Ehrenberg and by Kiitzing, with a note
of interrogation, among the Fragillarice. Thus the absence
of transverse striee does not seem a constant character,
or at least it seems that it ought not to be considered
essential, inasmuch as some of these doubtful species
(F. ? anceps, F. ? cimphiceras ) are striated. And Bailey
describes and figures numerous and evident strise, even in
F. pectinalis, mere'ly observing that “ it requires a high
magnifying power and skilful management of the light
to render these apparent.” In this genus, too, as well
as in the preceding one, and with a little more regularity,
we have frequently a cuneate form of frustule, resembling
that of Meridion. There is a highly important fact, in
an organ ographical point of view, presented by the
Fragillaria, in the variable length of the filaments as
compared with the invariable length of the frustules com-
posing it, a Variation probably induced by age. In the
paucity of our positive knowledge respecting the succes-
sive development of these beings, we must take this fact
into consideration. The internal substance presenls great
variety of distribution, as is shown by Kützing’s reducing
to F. pectinalis all the species on which Ehrenberg had
founded his character deduced from this substance. The
four species safely referred to this genus inhabit fresh
waters.

8 (bis). Grammatonema, a genus hitherto ill defined,
regarded by the author as intermediate between Fragil-
laria and IJiatoma , and to which Kiitzing, besides the

382 ANIMAL NATURE OF DI ATOME.®.

species of Agardh (G. striatula, G. Jurgensii ), adds, in
his work on Bacillariae, three marine species of Fragillaria
enumerated by Harvey (F. diatomoides, Grev., F. aurea,
Carm., F. Carmichaelii, Grev.), though with respect to
the last, Harvey himself objects to its position. I am
much more satisfied with the other plan suggested by
Harvey, to place it in Striatetta, for as the vittae are well
marked in tkis geuus, the species seem to belong to it.
Kiitzing himself, in the Phycologia Germanica, united
the two species ( striatula and Jurgensii ) of Agardh into
one corresponding with the Arthrodesmus striatulus of
Ehrenberg, clmnged the named Grammonema into Gram-
matonema, and refcrred this genus to the Desraidieae. As
to the Frag, diatomoides of Greville, with which I was
favourcd by Harvey, I think this conclusion right. It is
a true Hesmidiean, for it has no siliceous shield. And it
is to be observcd, that how perfectly soever it may
resemble the Fragillarics in form, it wants the longitudinal
canals and terminal perforations of the primary surfaces ;
and the internal substance is similar to that of the
Desmidieae. But as to the Conferva striatula (E. B.),
Sowerby’s figure certainly represents a Diatomean.
Wallroth has favoured me with a specimen tlius named,
collected by Jürgens, and it proves to be a Grammato-
phora. To the same genus, too, belongs the Fiatoma
striatulum, supplicd by Lenormand, whilst the Fragillaria
striatula , which I received from the same autlior, really
belongs to the genus Fragillaria , and corresponds per-
fectly with the F. virescens of Ralfs. So there remains
no small doubt in respect to this genus, which can only
be removed by a comparison of original specimens.

9. Diatoma. — Individua {linearia) cpuadrangula , sym-
metrice formata, primum in fascias conjuncta, demum
soluta et per isthmum gelineum motte plus minusve dis-
tinctum angulis concatenata.

The species with striated and perfectly linear frustules
(D. vulgare , D. mesodon , F. tenue ,) are precisely similar

ANIMAL NATURE OF DIATOME.E.

383

to Odontidia; and those with perfectly smooth frustules
[D. pectinale, 1). vitreum , B. hyalinum ,) to Fr ay Maria.
Therefore there remains no other character to distinguish
them except. the angular connection into flexuose chains ;
this character appears again in other genera ( Tabellaria ,
Gram matophora, Rhabdonema,) of distant sections. We
shall hereafter liave occasion to resume this subject. We
will only observe now, that this condition is always
associated with another, that of a peduncle by which the
chains are affixed to submerged objects. Perhaps it
happens more frequently and more remarkably than in
Odontidia and Frayillaria that we find in Biatoma the
cuneate form of frustules, and it is surprising to see
the inconstancy of the forms which Kützing, with in-
comparable diligence, has been able to collect, describe,
and figure, referring them to different species. Three
species ( B . mesoleptum, B. elonyatum, B. Ehrenberyii )
differ greatly from the otliers, being contracted in
the centre of the principal surfaces, and two of them
(B. elonyatum , B. Ehrenberyii ,) still more because they
are incrassato-capitate at the extremities of their lateral
surfaces. (In respect to the B. Ehrenberyii, Kützing
cites as synonymous my Glceonema Heißeri , because in
the specimen I sent him he saw only the Biatoma, which
is parasitic on the Glceonema, which he did not notice,
and so he made me appear to confound a Biatoma
with an Hydrurea. In the arbitrary selection he rnakes
of some characters from external form to separate
genera, families, and Orders, we cannot help feeling sur-
prise in finding united in the same genus species which
present differences so marked. The character of flexuose
concatenation, independently of organographic condition,
(which as we shall see is of little value, reappearing in
other groups,) ought to have mucli less systematic value
than those taken from the conditions of form, which may
be supposed to have a direct bearing upon internal
Organisation. For my part I think it would be much
more natural to place the smooth species ( B . pectinale ,

384 ANIMAL NATURE OE DI ATOMEN.

D. vitreum, D. hyalinum ,) in the genus Fragillaria ; those
striated with elliptico-lanceolate lateral surfaces ( Diatoma
vulgare , D. rnesodon, D. tenue, D. mesoleptum,) in Odon-
tulium. There vvould reraain, as distinctly generic,
the only two species which have capitate extremities on
their lateral surfaces, {D. elongatum , D. Fhrenbergii.)
These two proposed unions would be justified on both
sides, for whilst the Odontidia have forms little dif-
ferent from Diatoma , the Diatoma are little different,
from Fragillaria. But I wish it to be well understood,
tliat it is not my object to propose changes in the nomen-
clature or systematic arrangement of Diatomese. I only
intend to institute an organographic examination of the
proposed gencra and groups. And organ ographically
wc shall probably have more important distinctions than
those of form between Diatoma and the Fragillaria;
the latter have constantly two apertures at each extremity
of the principal surfaces, which scem to be wanting in
Diatoma , without adverting to the resemblance between
the Diatoma tenue var. dimotum and the very singulär
Bacillaria.

The character by which the last four genera ( Denticula ,
Odontidium, Fragillaria , Diatoma ,) are collected together
into one'family, namely Fragil] ariese, is the conformity of
the two primary surfaces ; nor do I know how the genus
Meridion is excluded, even by the minutest characters.
Kützing, indeed, cites the affin ities with Himantidia
among Eunotieae, with Diadesmis among the Naviculeae,
with the various genera of Striatelleae and Tabellarieae
among the Yittatae. The relation appears to us rather one
of analogy than of affinity, being the polypariform asso-
ciation of many individuals— conditions which associate
together almost every form ; and by this rule Melosira
might be allied to Fragillaria. As to internal substance,
Kützing says it is originally uniform in the shield of all
Eragillarieae, tlien divided into minute particles, mixed
with oily globules, or contracted into a spherical mass.

ANIMAL NATURE OF DI ATOMEN.

385

10. Cyclotella. — Tndividua singularia vel binatim
conjuncia , disciformia ; latus primarium distinctum, an -
nuliforme ; latera secondaria plana. ( lorica bivalvis,
valvis planis, orbicidaribus , annido interstiali conjunctis .)

With tliis genus there commences a series of forras
wbicli have a type totally different from the preceding.
In tlie former the two primary surfaces are always dis-
tinct, wliilst in those under consideration tliey unite in a
continuous cylindrical superficies. In the one the lateral
surfaces have always one diameter larger than the other,
so that they become more or less lengthened ; wliilst in
the other tliey are flat and circular, or convex and con-
cave, but always Segments of a sphere. In the preceding
series we have, indeed, among the Odontidia, the Fragil-
lari(E, and Diatomce , such a convexity of the principal
surfaces as is almost round, but the extremities remain
always distinct and in the lateral surfaces the striae
or any other processes run transversely without in-
terruption. Here, on the other hand, we have a very
evident radiated arrangement. This same arrangement
is presented in another family (Coscinodisceae) of another
group ; and there we sliall have occasion to mention it
again. In the genus Cyclotella we find species brought
together which in fact possess great similitude of external
form. But those from fresh water ( C . operculata, C.
Meneghiniana,) are free from attachment, and surrounded
by a gelatinous substance ; wliilst the marine species
( C. scotica, C. ligustica, C. maximal) are parasitic. But
if, again, we observe that the striae or radiating puncta of
the former are wanting in the latter, we shall find, in
that circnmstance, reason to suspect that even in internal
Organisation, to us entirely unknown, there may be very
remarkable differences. Ilence the observations ofNIigeli,
on what he terms a new species of Gallionella, and
which certainly ought to be referred to this genus, are
very valuable. (See Henfrey’s translation of Nägcli’s
‘ Memoir on Vegetable Cells/ in Ray Society’s Reports,
1846, Tab. VI, figs. 1, 2, 3; Tab. VII, figs. 27, 28.)

25

386

ANIMAL NATURE OF DIAT0MEJ5.

Among Kiitzing’ s species tliis could only be referred to
C. scotica, to which the autlior assigns a diameter of
whilst Nägeli says that bis species varies from 0-0 14"' —
O’O 27'"; but not being able to decide without comparing
tliem togetber, it is better, to avoid confusion, that the
supposed Gallionella should be named Cyclotella Neig elii.
In tliis species, which he examined whilst living, Nägeli
dcscribes and figures a nncleus of colourless raucus
attached to the wall of one of the two lateral surfaces ;
frora tliis, various colourless mucous threads extend thern-
selves, (sap currents, as in the Spirogyree,) which run
along the wall itself, or more rarely into the cavity, one
of which, howevcr, constantly goes across through the
axis of the cell, to the central point of the opposite over-
lying circular surface, where it forms a nucleus so soon
as thcre appears a diaphragm dividing the cavity itself
into two. This happcns as well in individuals that have
no siliceous shield, as in those that possess one ; for
Nägeli believes the shield to be externa], and referable to
an extracellular substance. A similar appearance of
arachnoid threads radiating from a centre was secn, too,
by Kiitzing, in Melosira salina. Globales of Chlorophyll,
says Nägeli, are distributed in two circles near the obtuse
ends of the cylinder, or are disposed in rays round the
nuclci of the two circular surfaces. It cannot be denied
that such observations favour the vegetable nature of this
being, but certainly they cannot destroy the value of many
others that support the opposite opinion. In my Cycl.
melosiroides , named by Kiitzing C. Meneg hiniana , I observe
that the deduplication ( sdoppiamentö ) constantly occurs in
individuals of smaller diameter, which on that account at-
tain a height proportionally and absolutely greater, that is,
a larger breadth of the interstitial ring. The Euganean hills
afford a new species to this genus, in their thermal springs.

Cyclotella concentrica : C. margine in lateribus secun-
darus concentrice definito, radialim striato. Diameter
varying from 0'008/// to 0*02///, and the striated margin
occupies about half the radius.

ANIMAL NATURE OE DIATOMEA5.

387

Taking also into accountthe two doubtful species {C.minu-
tula, C.Rotula), which Kützing justly snspects may be frus-
tules of Melosira, we have tlius nine species in this genus.

1 1 . Pyxidicula. — Individua singularia vel binatim con-
juncta, non conccitenata, libera vel versilia ; latus prima-
rium obsoletuni {nulluni) latera secondaria convexa. {Lorica
bivalvis, valvis convexis, annulo interstiali destituto.)

It is really surprising tliat although Agarclh, Kützing,
Ekrenberg, and Brebisson, have described and figured the
Cymbella or Frustulia operculata as the type of this
genus, and corresponding perfectly witli the foregoing
generic character — Kützing himself, without acquainting
us witli the mistake of others, or his own, sliould now
form the type of the preceding genus froni this same
species, preserving the name at first proposed, but
altering the sense ; and at the same time should describe,
as a new species of Pyxidicula, the P. operculata of Bailey,
which seems either identical witli that of Ehrenberg, or
very similar to it, and to that formerly so described and
figured by the authors named above. The fact is, that
the specimens of Brebisson and Lenormand, in my pos-
session, belong to Cyclotella, and not to Pyxidicula. The
other species {P. rnajor ) described and figured by Bailey
and Kützing, seems rightly to belong to the tribe of
areolated Diatomese. Of the species included in flints {P.
globcita, P.prisca,) we can say nothing organographically,
so uncertain is their nature. The P. adriatica is a heilig
equally singulär, of which we know nothing in an organo-
grapliical and physical point of view. The same may be said
of Ehrenberg’s two genera {Goniothecimn, Rhizosolenia),
which Kützing places doubtfully at the end of Pyxidiculce.

12. Pododiscus. — Individua singularia vel concate-
nata, siipitata ; latus primär ium obsoletuni {nulluni) latera
secondaria convexa. Stipes lateralis. {Lorica bivalvis,
stipitaia valvis convexis , subhemisphericis.)

The only species {P. jamaicensis) is too incompletely
knovvn for anything positive to be inferred.

388

ANIMAL NATURE OF DIATOMEjE.

13. Podosira. — Individua concatenata, distinctissime
stipitata, lorica ut in prcecedenti p euere. Stipes cen-

tralis.

The Podosira are raerely concatenated Ppxidiculce,
and this concatenation results from the persistence of the
fine external membrane within which the deduplication
{sdopjnamenlo) takes place, precisely as in the next genus,
in which examples are not wanting of an uniting isthmus
and peduncle, by which the Melosirce also sometimes
become stipitate. To the tvvo species of Kützing ( P .
hormoides, P. Montapnei ,) both exotic, we can add one
from the Adriatic :

Podosira adriatica : P. arliculis sphcericis, vix de-
pressis. Sig. Stalio found it in Dalmatia, parasitic upon
Callithamnion Borreri. The articulations are in trans-
verse diameter, which is the longer 0 046"', in longi-
tudinal diameter 0-04'", or a little more, and frcquently
the two diameters are ecjual, and the form perfectly
spherical. Though not differing from P. hormoides,
except in the lesser depression of the articulations, I still
consider it different because of the constancy of that
character. Kützing, to whom I sent it, suspects it to be
the same as in P. hormoides. Por my part I hesitated a
long time whether l should not refer it to a form of Melosira
monoliformis, since in the Melosirce, evcn, the interstitial
ring is at first absent; but besides that I have found its
absence in very numerous specimens to be absolute, I
found nothing that I could refer to the annular channels
of the Melosirce. Every articulation is constituted of two
valves, perfectly hemispherical, which separate on being
pressecl; and eacli pair is contained in a cylindrical
sheath, which embraces and surrounds the contiguous
lialves of the two articulations. This sheath has a re-
markable firnmess, for when the articulations are broken
or separated, it remains wicle open and unaltered in
figure. It is crossed transversely by fine strise, eight of
which are contained in O’OOyö'". Tliey are formed of as
many series of minute points, projecting like papillse. It

ANIMAL NATURE OF DIATOMEjE.

389

often happens tliat the two articulations are separated a
little frora each other, and the externa! tnbe is then con-
tracted in the intermediate space, perhaps indicating the
origin of the isthmns. I never succeeded in observing
more pairs connected together. The stipes is little
inferior in length to the diaraeter of the articulation.
Longitudinal folds are always present, which I believe to
be six, since there are always four (at least ?) on each sur-
face. I have never succeeded in obtaining a sight of
that central aperture in the lateral surfaces, from which
Kützing says he has seen the stipes to issue both in Podo-
sirce and Melosirre, especially the marine species. Finally,
I observe that within the articulation there appears an
open space, which is entirely owing to the internal sub-
stance, for it is destroyed wholly by fire or acids.

14. Melosira. — Individua concatenata,adnata. Lorica
bivalvis, valvce cingulo v. annulo interstitiali tenerrimo
maxime hyalino conjundce.

“ * Lysigonium. — Articidis globosis vel ellipticis, prope
utrumque finem carina annuliformi instructis.”

“ ~~ Gallionella. — Articidis cylindricis, non carinatisP

The Melosirre in general may be regarded as poly-
pariform associations of Cyclotellce, and the comparison
prevails principally in the second sub-genus. The dis-
tinction of the two sub-genera is also proposed by Hassall
(Spheerophora, Meloseira), but it is to Kützing we are
indebted for establishing it upon the important character
of the carina, which occurs only in the first two specics
[M. salina, M. nummuloides) , a character on whose
organographic value we cannot decide anything, but
which merits some consideration in a morphological
point of view. For that projecting ring bounds the lateral
surfaces ; whilst in the other species, with sides more or
less convex, these are continuous, as it were, with the
primary surfaces. In all the species we may notice
the double furrow which forms a ring connecting the
body of each individual laterally to the interstitial ring;

390 ANIMAL NATURE OF DIATOMEiE.

tliis furrow or canal presents apertures disposed in a
regulär manner. Kützing believes these supposed aper-
tures to be sections of the canals themselves, that is,
portions of them seen in projection. This opinion is the
only one consistent with the fact, that the filament being
cylindrical, and therefore presen tingitself indifferently on
every side, these apparent apertures are always seen
arranged near the margin. Ehrenberg’s assertion that
they are more numerous in some species, does not seeni
to be confirmed. This appearance is still more compli-
cated, inasmuch as these fine tubulär canals project from
the internal surface of the shield, and a slight furrow
externally corresponds with them. This condition is
evident in Melosira distans, in which, owing to the
greater depth of the furrow, the apparent perforations
remain separated from the margin. The interstitial ring
presents peculiarities of which we liave no instance in the
preceding genera. Its tenuity and the great variety of its
extension are important characters. But liere we must add
the vcry important one of the changes it undergoes during
observation. It is not uncommon to see the two halves of
the articulation separate themselves sloudy, and enlarge at
the same time with the ring. This fact is not decisive in
rcspect to the great question of the animal nature of
these beings; for it is not subject to a subsequent con-
traction, and because in plants we liave the analogy of
Spirogyrcc, in which, on the rupture of the outer tube,
the extremities of the articulation, which were inflected
like the fingcr of a glove, expand themselves as if by
elasticity ; but many facts controvert this inference. In
support of the opposite opinion, is the frequent enlarge-
ment of a particular articulation, in a manner similar to that
of the (Edogonia . But Hassall justly observes, “ for this
endochrome .... never becomes Condensed into a dis-
tinct organ or sporangium . . . for this reason, the
resemblance is reduced to a mere appearance. As to
this supposed endochrome, proofs are certainly wanting
that it is an ovary, as Ehrenberg supposes ; but they are

ANIMAL NATURE OF D1ATOME/E.

391

also wanting to shovv that it consists of gum, starch, or
Chlorophyll, which woulcl be necessary were it a gonimic
substance, as advanced by Kützing • and analogy even is
wanting, for we do not see, in any Alga, a sirailar dis-
position of the internal substance. The often quoted
resemblance to the Confervae cannot even be deemed
apparent ; for in no Confervae are distinct spherules met
so regularly, or disposed so symmetrically. Düring desic-
cation it happens in the marine species, as in the Podosirne
already described, that the internal substance adheres to
the inner wall in the form of oily globules surrounded
by a distinct, transparent margin, and compressed one
against another in the form of regulär polygons. Ehren-
berg also speaks of diaphanous vesicular spaces, which he
regards as stomachs. Kützing enumerates, figures and
describes nineteen species, marine, freshwater, and fossil,
besides the four doubtful ones placed at the end, and the
famous ferruginea {M. ochracea , Ralfs,) which he proves
not to belong to the dass of Diatomese.

We have a new species in the Euganean thermal
springs ; this is so different from all the others, that it
might serve as the type of a separate genus, which,
meanwhile, I propose as a subgenus, with the name of
Pleurosira ; articulis cylindricis non carinatis isthmo
laterali angulatim concatenatis. The specific description
will be as follows.- — Melosira ( Pleurosira :) thermcilis: major,
articulis cylindricis solitiariis, isthmo laterali angulatim
concatenatis, disco laterali levissimo. Hab. inter Clado-
phoras et Lyngbyas in thermis Euganeis temp. + 30 R.

The diameter varies from ^ to -4 of a millimetre (5 to
8 centomillimetres). The lengtli of the articulations is so
variable, that I did not think it proper to mention it
m the description. The sliortest scarcely exceed the
diameter, but others are twice or thrice as long. In the
smaller spccimens the interstitial ring exceeds a little in
breadth the two lateral circular bands which form part of
the secondary surfaces. A distinct and large circular
canal, evidently projecting into the internal cavity, and,

392

ANIMAL NATURE OF DIATOMEiE.

corresponding to an external furrow, bounds tlie ring itself
on botli sides, and is easily discernible, also, from tbe
diminished tliickness of tlie wall. Wliere this ring is
most dilated, it presents two fine circular strise, which
divide it into three bands, tlie central one being tlie
narrowest. In tlie longer articulations tliis central band
is as broad as tlie otliers, or broader, and finally tliere
appears a tliird circular line, and a corresponding dia-
pliragm, wbicli divides it. The wall of tlie two bands
resulting from tlie division of tlie central one, grows
thicker, and tliese become similar in every respect to tlie
lateral valves of tlie two contiguous articulations. JBut
no sooner are tlie two articulations complete, than they
dctacli themselves from one another, and nothing remains
Io connect tliem but a lateral isthmus, in appearance like
a joint ( forme apparente de cerniera ) (hinge), as in
Diatomce and Grammalophorce. The internal substance,
in dried specimcns, is in tlie form of splierules, adhering
tenaciously to tlie internal wall of tlie secondary surfaces ;
and one row only of tliese splierules adlieres also to tlie
interstitial ring by the side of tlie canal, in a similar
nianner to tlie teetli of the M. sidccda. Only wliilst tlie
two articulations are being completed, tliese globules are
found in the intermediate space. On one occasion I
liave seen an articulation inflated as in M. varians. The
isthmus is indistinctly unilateral and alternate.

At first siglit of this singulär Diatomean, tlie mind
instantly recurs to tlie figure of the Odontellce ; and tliis
resemblance is more strongly suggested by the figure
given by Bailey of bis Gallionella, (pl. 11, fig. 8,) which
Kützing refers to Odontella polymoipha, a figure which,
except for the contraction corresponding witli the circular
canals, coincides perfectly with our species. Were it
only that Bailey, when comparing his Gcdlionella with
Liatoma auritum , insists upon its cylindrical form, its
want of appendages, and the mode of connecting the
articulations by a' “flexible liinge-like ligament,” T
believe that Bailey miglit with justice regard his species

ANIMAL NATURE OF DIATOMEyE.

393

as beloiiging to Gattionelia or Melosira, and I propose
to name it. Melosira ( Pleurosira ) Baileyi.

The celebrated Kützing, to whom I communicated
these remarks, replies, “ your Melosira ( Pleurosira ) ther-
nialis is in no respect different frora the Odontella poly-
morpha. I have compared yonr specimen with that of
Montagne. There are even found the delicate ( zarten )
points npon the shield, as in the other which I have
inadvertently omitted in my figure. Your specimen is
certainly an Odontella , although the articulations are
cylindrical {t er et es), for it is the same also in the 0. aurita.
I think of uniting, in future, the Biddulphiese with the
Tripodiscieae.”

Although I have had an opportunity of examining
fragments only of Montagne’s Isthmea polymorpha, ad-
hering to an imperfect specimen of Polysiphonia subti-
lissima from Cayenne, with which the celebrated author
favoured me, I am still positive in treating the matter
differently. It is admirably figured by Kützing; the
articulations are not cylindrical, and though obtuse and
slightly prominent, the lateral processes are very evident.
Whether this belongs to the same genus as other Odon-
tellce , and whether that genus belongs to the family of
Biddulphieae, and to the Order Areolatae, is a question to
which we shall return.

Now, resuming all that has reference to the family of
Melosireae, we shall find, as a character common to tliem
all, the circular figure of the vertical section parallel to
the lateral surfaces ; a character which, as well as the
other, of a radiated disposition of the striae upon the
lateral surfaces, we shall find repeated in the family of
Coscinodisceae, which, having the shield of a cellular struc-
ture, belong to the tribe of Areolatae. Perhaps we may
suspect some Melosirce ( sidcata , decussata, lirata,) to be
furnished with the same organic condition, and lience
arises a tresh doubt respecting the systematic value that
has been ascribed to it.

In general we may also say, that in the Melosireae the

394 ANIMAL NATURE OF DIAT0MEA2.

development of the lateral surfaces prevails over that of
the primary ones, which we find finally to disappear in
certain genera ( Pyxidicida , Podosira ,) as well as in some
species of Melosira ( vcirians , orichalcea), the increased
length of the articulations involving the corresponding
development of the primary surfaces. And it is to be
observed, that although in this family the primary sur-
faces differ precisely as much in form as they do in the
three preceding ones, yet we find in these the same
organic character as in the greater number of the other
genera, viz., the presence of longitudinal furrows or
canals. The Separation of one lateral surface or valve
from the other, with the consequent dilatation of super-
ficies, which the primary surfaces exhibit before the du-
plication takes place (though verified to some degrce in
other genera, yet in the Melosira bettcr than clsewhere),
presents an undeniable analogy with the reduplication of
Desmidiem, which Brebisson distinguishes from the de-
duplication of Diatomese. The particular disposition of
the internal substance, the currents or mucous threads
radiating from a centre, the enlargement of some arti-
culations, and the dilatation of the interstitial ring, are
isolated facts, which however merit particular attention
in the paucity of our knowledge.

15. Campylodiscus. — Individua sinyularia , disoifor-
mia ; discus curvatus vel tortuosus , rotundato-ellip U cus
radiatus.

Although I have hitherto only been able to examine
that one species of this genus ( C . elypeus,) which is
found in the fossil flour of Santa Fiore, in the kieselguhr
of Franzensbad, and constitutes the entire substance of
the tripoli of Eger, I think I can add something to
wliat Kützing says of it. He indicates, indeed, in
fig. 5, the thickness of the margin, which, in this in-
stance, represents the primary surfaces uniting together
into a continuous superficies, but neither in the other
figures nor in the description does he notice it any

ANIMAL NATURE OF DIATOMEiE. 395

more. Now, this superficies merits the rnore considera-
tion because, referring it, as analogy requires, to the
primary surfaces, it offers au exception to the general
law that the transverse striae are wanting. For these are
very evidently continuous, and therefore may be com-
pared to those upon the lateral or secondary surfaces of
Denticula, of Odontidium, and Diatoma. We noticed
the same condition before, treating of Odontidium, in the
Syrinx annulata of Corda. But there remains that otlier
character of the primary surfaces which seems to have
the more organic importance, — the longitudinal division.

I have not seen the intermediate gradations, but I
have certainly seen two individuals, one superimposed
upon the other, and adhering closely, which might fairly
be regarded as proceeding from the deduplication (sdop-
piamento) of one individual. This brings new support to
the affinity of this genus with the Melosirre suggested by
Kützing. That microscopical observations are to be
interpreted with the severe scrupulosity of critical logic
is well known to those who habitually use that valuable
instrument ; and the prudent caution will be more re-
quisite when we have before us a fact at variance with
many others. T ought not, therefore, to suppress a
doubt that occurred to me relative to the continuity of
these transverse striae over the primary surfaces. In
hundreds of individuals I have succeeded in obtaining a
front view of the margin, and in seeing it crossed by
those thick striae which correspond to the radii of the
lateral surfaces. These are among the microscopic ob-
jects which may be regarded as gigantic, and in respect
to which we may banish all suspicion of illusion. But
it may be supposed that in all such cases I have had
before me only one of the lateral valves, and that the in-
terstitial ring was wanting. Individuals geininate through
an antecedent deduplication might have removed that
doubt. But these are rare, and owing to the complica-
tion produced by the Superposition of four similar trans-
parent valves, I could not safely decide whether the striae

396

ANIMAL NATURE OE DTATOMEjE.

were continued through the entire depth of a cylinder
which I could only see obliquely or in front.

As to the interruption of the radii, which is regarded
as a specific character, this is not at all constant, and
may, perhaps, depend upon the imperfect state of the
speciraens. The dotted appearance of the central disc
ajways presents tliat regularity which Kützing only
represented in the fig. 5 before raentioned. Similar puncta
may also be seen in the spaces between the radii. The
central apertu re described by Ehrenberg is rightly denied
by Kützing. A sort of analogy in form connects this
genus with some species of the next ; the only distinc-
tion I believe to be a repetition of that very important
character of transverse striae on the primary surfaces.

16. Surirella. — Individua singularia navicidaria ,
margine striata ; latus secundarium primario majus, linea
media longitudinali leevi percursum.

This genus is divided into four distinct sections. The
first comprises the flexuose species, (iS. clgpeus, S. Cam-
pilodiscus, iS. Jlcxuosa, S. elegans, S. spiralis, S. Myodon ) ;
and really one is at a loss to find the motive that could
induoe Kützing to separate these generically from Cam-
pylodisci. In fact there only remains, in my opinion,
the above-mentioned character of striae continued over the
primary surfaces in Campylodiscus clypeus to distinguish
that genus. But the doubt already expressed as to this
character, acquires still' greater weight when we compare
these Campylodisci with the flexuose Surirella.

In the S. Campylodiscus Kützing represents (PI. xxviii,
fig. 26, c, d,) the lateral valves detached, which give a
perfect figure of a Campylodiscus, and thcir inclined
margins viewed in front ( a , b,) resemble transverse striae
on the primary surfaces.

The species (S. didyma, S. solea, S. regula, S. multi-
fasciata, S. thermalis,) narrower in the centre than at
the extremities of their lateral surfaces (medio plerumque
constricta) are, in the opinion of Kützing himself, so

ANIMAL NATURE OF DIATOME2E.

397

allied to the Synedrce, that there remains no character to
distinguish them. except tliat tliey are free, whilst the
latter are parasitic and affixed.

I confess that I cannot coraprehend by what motive
Kützing divides the numerous species that follow into
two sections, (oblongse, ellipticse et ovatoe.) Were there
a difference, how small soever, but constant, this might
have a systematic value as rendering the distinction of
species more easy ; but we have only to compare together
the two species craticula and bifrons, which figui’e in
the two sections, to convince ourselves that the distinction
proposed is not based on a constant character. And it
causes real surprise to find enumerated in the second of
these sections a species (S. angusta ), which it is trne has
not the median contraction, but, from similitude of form,
would by any one be supposed to belong to the section
preceding, which we say is allied to the Synedrce, and in
which section we have the S. regula and S. multifasciata
both equally wanting in that character. Comprising,
then, in a single group, both these sections, we assert
that here exists that important character of the secondary
surfaces exceeding the primary, which, as before stated,
forms the contrast with the Denticulce. But even amo'ng
the latter there is not wanting an instance ofthe opposite
condition (D. undulata .) The new Surirella Jenneri, of
Hassall, as well as Denticida constricta, has the primary
surfaces perfectly equal in dimension and form to the
secondary. After all I believe that affinities and dis-
tinctions are rather to be sought in internal Organisation
than in external form, the latter having no organogra-
phical value except as an indication of the former. With
regard to structure, though we are still far from having
sufficient data whereon to establish any principle of
Classification, yet we find in Surirella, more, perhaps, than
in any other genus of Diatomeae, a multiplicity of organs
and a complex Organisation. The S. striatiäa, of which
Turpin and Corda have given figures of little accuracy
and in a great dcgree imaginary, supplied to Ehrenberg

398 ANIMAL NATURE OE DIATOME2E.

materials for numerous and valuable observations. It
would appear that Kiitzing, anxious to establish the
vegetable nature of Diatomese, designedly passed over
tliis argument, and sought to distract attention by creating
new species out of the various forms assuracd by S. stria-
tulci at successive periods of age and degrees of de-
velopment. Such we may suspect to be bis 8. Pala
and 8. ovata, as well as the 8. ovalis of Brebisson, who,
as early as 1835, and not in 1838, had made public his
S. biseriata, a name, therefore, which ought to be
retained in preference to the later one (8. bifrons ) of
Ehrenberg. Bailey, too. noted the quick and lively move-
ments of 8. striatula, and I had frequent opportunities of
observing it in our Euganean warm springs. I could
compare togethcr living individuals, among which there
occurs an indescribable complication of internal structure,
and dead skeletons, such as are represented by Kiitzing.
Nor can 1 omit here the 8. gemma, in which Ehrenberg
discovered numerous cxtcnsible and contractile cirrhi
which appeared to serve as Organs of motion. It appears
that Kiitzing had seen something similar in 8. solea,
(PI. iii, fig. Gl, 2a.) And in regard to 8. gemma we
must remembor the lateral openings frora which, accord-
ing to Ehrenberg thesc cirrhi are protruded ; openings
which it would seem must exist also in 8. fastuosa, and
which remind us, also, ofthose before mentioned in some
species of Epithemia, as the cirrhi remind us of the cilia
of E. ciliata ( Navicula ) of Corcla. It appears to me
that it is now with Diatomeae as it was with Mollusca
down to the time of Cuvier, and that anatomy has to
effect the same beneficial revolution in their natural
Classification, which it produced in the System and
nomenclature of Conchylia.

Kiitzing finally ascribes to the same genus Surirella ,
as the last section or sub-genus ( Podocgstis ), that species
which I found to be so common in our sea, and which
he therefore names adriaüca ; tliis association is truly
singulär, for wliilst we see that the second sections are

ANIMAL NATURE OF DIATOME/E.

399

merely distinguished from Synedrae because they are not
affixed, we find the Podocystulce stipitate and affixed.
Yet do I intend to maintain that it is not allied to the
other SurirellcB. I only notice how vacillating are the
principles of the proposed Classification. The Podos-
phenia of Hassall, excluding the synonyms, seems to
belong to this sub-genus.

17. Bacillaria. — Individua bacilliformia prismcitico-
rectangula, linearia, primum in seriem rectcrn tabulatam
transversim conjuncta, dein in series obliquas dimota.

The singulär appearances assumed by the only species
of this genus [ß. paradoxe :) and the liveliness of its
motions have long been celebrated (Müller). The prin-
cipal organographical character that distinguishes it from
the Fragillarice is the same that allies it to a different
group of the family, viz., the interruption of the trans-
verse strise in the median line of the secondary surfaces,
to which is added the parallelism of the primary surfaces.
Hassall overlooked the former of tliese characters in the
figure he gave of this species. The physiological cha-
racter of mobility of the frustules, and the symmetrical
disposition which they assume, becomes the more im-
portant, inasmuch as they do not recur in any other
Diatomese ; and therefore we believe that they merit this
particular mention.

18. Synedra. — Individua bacillaria , prismatico-rec-
tangula, demum uno vel altero fine adnata : latus secun-
darium primario cequale , vel anguslius, linea lavissima
media longitudinali percursum.

* Scaphularia. — Minuive, rarissime adnatre , Icevissimve ;
( non transversim striata.)

The eleven species enumerated in this sub-genus are
only classed together by negative characters, viz., the
want of the characters of other genera more or less allied.
In general it is only required that they should have tlicir
secondary surfaces marked with transversc striae, either

400

ANIMAL NATURE OF DI ATOME.®,

continued or interrupted, to be placed among the Den-
ticulce or the Aurirellce. In one ß. quadrangula ) we
have the character of Denticulce, the excess of the pri-
mary surface over the secondary; in others ß. virginalis ,
S. constricta ,) we have the median contraction of the
primary surfaces characteristic of the second section of
Surirellce. Thns, indeed, all these species only want the
central aperture to belong to the Nciviculce or Acli-
nanthidia ß. Biasollettiana). Certainly we cannot say
that the presence or absence of these characters is of
little importance; we have only to remark that with the
highcst powers of the inicroscope it is often impossible to
decide with certainty whether they have the transverse
striae and the median aperture or not.

** Ecliinaria : Icevissimce, demum cißxce et plerumque
radiatim aggregatce.

The seventeen species contained in this section do not
differ materially from those in the former, except in being
affixed. Many of them are attenuated at the extremities
of their primary surfaces ; but those destitute of that
character ß. amphicephala , S. tenuissima , S. tenuis,)
have great analogy in form with the Ulnarice. We have
also species in this section that are curved in their
secondary surfaces ß. curvula , S. Arcus,) and in their
primary ones, ß. lunar is, S. bilunaris,) which resemble
the Eunotice and Achnanthidia. The S. ampl acephala
is distinguished from all by its dilated extremities.

*** Ulnaria : cißxce, flabellatim disruptce, in latere
secundario, excepto spatio medio longitudinali Icevi, trans-
versim striatce.

Although the twenty-four species of this section have
nothing in common but the general character of all the
Sgnedrce (their bacillary form and the absence of a
median aperture), still we find enumerated among them
species that are unattached, ( armoriccina , signioidea,
vermicularis,) and even destitute of the characteristic striae
( venniculciris ) ; and this becanse the spirit of System (spirifo

ANIMAL NATURE OF DIA'L’OMEjE. 401

systematico) lias not gone the length of separating them
from the other species witli which in all other respects they
have superior affinity. And as to the transverse striae,
this character of their interruption at the median line,
which is not only stated in the clefinition of the section
and of the genus, but is even taken for the basis of
Classification in the primary division of Diatomece non
vittatee astomaticce, clearly fails in very rnany species,
( pramorsa , aequalis, mesolepta, Ulna , danica, splendens ,
arrnoricana , sigmoidea, scalaris ,) in which these striae are
continuous, as in Denticidce. The I). oblong a may be
compared with the above-named species. And it is also
to be remarked, that though the transverse striae are
continuous in these species, as Kützing has accurately
delineated them, still the characteristic transparent median
line remains visible when the object is withdrawn to the
remotest extremity of the microscope, which proves that
there must be a longitudinal furrow traversing all the
striae ; and to ascertain its depth it woulcl require that
the screw regulating the movement of the stage or of the
microscope should be micrometric. This slight furrow is
also visible in a fragment that accidentally presents the
transverse section of such a Synedra. The type of this
section is S. Ulna, and many other species as well as this
[acuta, oxyrhyncus, amphirhynchus, valens, arrnoricana,
sigmoidea , vermicularis,) have the primary surfaces per-
fectly linear ; but others, again, have the extremities of
these surfaces attenuated ( debilis ), like the greater part
of those of the preceding section ; others only rotundate,
[premorsa, spectabilis, scalaris ,-) in reverse of these
many are contracted in the middle, and cuneate and
truncate at the extremities, [lanceolata, mesolepta, aequalis,
vitrea , danica, splendens, biceps, capitata .) Among the
latter we have three, [danica, biceps, capitata ,) which, in
the important character of capitate extremities of the
secondary surfaces, resemble the ampliicephala of the
preceding section. And in the greater number of species
in this section, as well as in some comprised in the

26

402 ANIMAL NATURE OF DI ATOMEN.

former, {not ata, Martensiana, Vaucherice,) the form is so
similar to that of Naviculce as to leave liotliing but the
want of central aperture to distinguish tliem. Einally,
there are not wanting in this section species more or less
curved. 'L'hose that are curved in the secondary surfaces
{mesolepta, biceps,) might be regarded as similar to
JEunotice , but they difler essentially in being attached.
Those again which are curved in the primary surfaces
{Ulna, tergestina, armoricana, sigmoidea, vermicidans,)
have analogy only with the Achnantheas. As to the
Sigma, Kützing himself avows his suspicion that it may
belong to the llaphidogloece.

**** Tabularia ; bacillis in stipite brevi, horizontaliter
crescentc, tabulalim disruplis.

Exclusive of two {S. Gallionii, S. Arcus,) all the spe-
cies (9) of this section want the transverse strise; and all
have that linear form, slightly attenuated at the ex-
tremities of the primary surfaces, which we have noticed
in many species of the preceding section. The distinctive
character of this section, the stipes on which the frustules
grow side by side contiguous to each other, is very im-
portant in an organographical point of view. And by
this character the species described and figured by
Hassall under the name of S. lunaris would seem to
be related to the S. Arcus , if it be really distinct.

***** Grallatoria ; stipite elongato scepe ramoso, ba-
cillis plcrumque geminatis loevibus.

Among the six species of this section, which in their
aspect call strongly to mind the family of Licmophorem,
two are perfectly linear on the primary surfaces, (&
crystallina, S. gigantea ,) and one of tliem ( gigantea ) has
the extremities of the secondary surfaces capitate. The
rest have the primary surfaces attennato-truncate at the
extremities. All are smooth, wanting striae.

ANIMAL NATURE OF DI ATOMEN.

403

****** Rwiaria ; bacillis in tabulam connatis , demum
modo Diatomatis disruptis et angulis alternis cohcerentibus.

Besides the sectional character which intimates an
analogy with Biatoma, the only species that figures here
{S. rumpens) differs from all the other Synedrce by the
tumid and rounded extreraities of the primary surfaces.

From tliis rapid examination of the sections into which
the seventy species of Synedrce are divided, and to which
Kützing adds seven more as uncertain, it appears that
very different relations might be established among them;
and that if in the greater portion an evident similitu.de
in form would seem to indicate a very distinct genus, in
many there appear indications of resemblance to genera
and families totally different. We must therefore repeat,
in this instance, that in the want of data whereby to
judge of the organic importance of character, and in
the arbitrary nature of the selection, of necessity resulting,
Kützing has achieved a supremely laborious and diligent
task, by discriminating, describing, figuring with won-
derful accuracy, and distributing with some sort (qua-
cunque ) of systematic Order so immense a number of
species. As to the organ ographical considerations which
can be instituted in this genus, they reduce themselves
to the single one of length predominating over breadth,
and the eminently bacillary form derived from it. Thus
Kützing observed the opposite characters of Synedrce and
Surirellce ; that the lateral surfaces exceeded in one, the
primary surfaces again in the other. But it is not in this
that the Opposition really exists. For even among the
Surirellce we have some ( medio plerumque constrictce ) of
those which do not exhibit the boasted prevalence of the
lateral surfaces, and which, therefore, we might with
equal propriety enumerate among the Synedrce ; whilst
almost all Synedrce of the first section ( Scaphdaria ), and
some of the second (. Echinaria ) want even the last dis-
tinctive character that would remain, — of being affixed.
The surfaces, which in all Synedrce are really reduced to
the smallest dimensions, are the two which in Surirellce

404 ANIMAL NATURE OF DI ATOME.E.

of the last two sections, [oblong ce, ovatce , elliptica,) and
in tlie sub-genus Podocystis, still remain very evident,
viz., the terminal surfaces. Kützing observes, tliat in
conformity with the flattened form of the Surirellce, and
the lengthened form of the Synedrce, the intermediate
spaces are placed laterally on the median line of the first,
and are accumulated at the extremities of the second.
But this accuimilation never occurs nntil after death.
Whilst tliey are alive the internal colouring substance is
mostly situated along the median line of the lateral sur-
faces, or sometimes along the sides of tliese, and then in
four to eight distinct lobes. In some species it is dis-
posed in symmetrical and equidistant transverse fasciae. In
the central region thcre is often a transparent space, and
many otlier varieties are met with ; tliese are quite suf-
ficient to indicate a complicated Organisation, but we do
not know how to interpret them rightly. Finally, we
ought not to pass over in silence the important organic
condition of two very distinct longitudinal lines on each
of the primary surfaces, terminated at both extremities in
minute Perforation s ; a condition clearly delineated by
Kützing in seventeen species, and which, in the smaller
ones, we may suppose to have been obscure, or even
unobserved.

Comparing together the four genera ( Campylodiscus ,
Surirella t, Bacillaria , Synedra,) which constitute the
family of Surirelleae, it is easily perceived that the last
two only deviate from the Fragillarieae by the character of
interrupted striae ; and the first two deviating sensibly in
the succession of species from the circular shape of the
lateral surfaces, or of the transverse section, establish a
transition between the Melosireae, and the group formed
of these two genera, along with the Fragillarieae and the
Meridiese. Hence it is impossible to establish an organo-
graphical character that shall embrace the entire family
and strictly represent its type. For even restricting the
organographical data we possess to the predominance of
the vertical surfaces (primary and secondary), with the

ANIMAL NATURE OF DI ATOMEN. 405

greatest reduction of the terminal ones (inferior and
superior), such as we have in the Fragillariese and the
Meridiese, but without the predominance of the primary
over the lateral, as in the former, — what value these
characters have, in what relation they may stand to
internal Organisation, I do not believe that we can decide
in the actual state of Science.

The five families ( Eunotiece , Meridiea, Fragillariece ,
Melosirece, Surirellece,) united together and arranged in
two groups, as they have the strise continuous (the first
three), or interrupted (the last two), constitute the Order
Astomatica, or those wanting a character that is regarded
as essential to the following order.

19. Cocconeis. — Individua singularia eiliptica, de-
pressa, latere sekundär io foraminifero adnata, nun quam
stipitata, latere superiori medio longitudinaliter impresso-
sidcato.

The general form of Cocconeis is that of a disk of an
ellipsoidal figure, with surfaces more or less exactly
parallel, plane, or slightly curved. It corresponds, tliere-
fore, to the figirne of Campglodiscus and the flexuose
Surirellce ; for in this genus, as in those, the secondary
surfaces prevail so much that the primary are reduced to
a simple margin. We know these to be the secondary
surfaces by the trans verse or radiating strim with which
the superior surface in rnany species is marked, and by
the central Perforation of the inferior surface ; and
because the division which is effected parallel to these
corresponds to the marginal fascia which represents the
primary surfaces. Contrary to all the genera hitherto
examined, it is precisely by one of these secondary sur-
faces that the Cocconeis adheres to those filiform algae,
on which it lives parasitically. Hence their resemblance
to the Epithemice is only in appearance. The individuals
multiplied by duplication become quickly free, for it is
rare to find them geminate ; but they soon adhere
parasitically to Algm, and collect together in great mul-

406 ANIMAL NATURE OF DIATOMEiE.

titudes. Most of the freshwater species are perfectly
smooth. It is remarkable tliat the form of C. Pediculus
{C. Kützing ce , Breb.) is conico-truncate; tliis is not noticed
by Kützing in bis definition, much less in the figure, on
which account, before asking for his opinion of my own
specimens, I thought he was describing a different species.
Hence, in the duplication, the snperior individual becomes
smaller than the inferior; and from the same condition
it results, tliat the m argin appears bilineate when it
is simple, as Kützing figures it, and trilineate as the
same Kützing describes it in the specific definition,
when it is merely in the course of duplication. The
marine species display on their superior surface very
elegant transverse granulated striae, which either extend
across the entire breadth without interruption, or radiate
either from a median line or a central space. In only a
few species the striae are longitudinal, or concentric and
waved (flexuose). The ulterior characters by which the
thirty-four species of tliis most elegant genus are distin-
guished one from another, are still very sliglit.

20. Doryphora. — Lorica simple® bivalvis quadrangula
navicidaris non concaienata, apertura in latere secundario
nulla ; linea suturali media longitudinali ; stipitata.

The principal characters of the family are wanting in
the single species of this genus {D. amphiceros.) Fixed
at one of its extremitics by a stipes, and wanting the
central aperture in the secondary surfaces, it differs from
the Snrirellce only by the continuity of the transverse
striae. In respect to the central aperture, Kützing
observcs, that it may even be wanting in the Navicula
themselves, and may be wanting in some individuals
though present in others of the same species. On a
character like this is based the difference of the Orders.
With more right, and supported by numerous facts, I
can assert that there is a continuity of the striae in many
Suriretta. Hence I regard the Doryphora as allied to
these, and particularly to the Podocystidcc.

ANIMAL NATURE OE DIATOMEAS.

407

Now with regard to the family of Cocconideae I can
on ly repeat what has been said of the genus Cocconeis,
that it presents a new type of Organisation, differing
from the preceding, summarily, in this, that the temno-
genesis is effected transversely in the direction of the
body, though vertically in respect to the point of attach-
rnent ; in other words, that in these the surfaces become
superior and inferior, which in the others were lateral.

21. Achnanthidium. — Individua simplicia, singularia
vel binata, libera ; a latere primario linearia genuflexa.

Admitting it to be proved that in the species of this
genus (A. microcephalum , A. delicatulum) there positively
exists a median aperture in one of the lateral surfaces
and not in the other, and that two perforations exist
at the extremities of the primary surfaces, as stated in the
definition of the order and in that of the family : admit-
ing this, we should still have to decide whether the un-
certain relations of these characters to other families,
and their inconstancy, will give us any right to erect a
distinct genus on principles so slight and precarious.
This is, indeed, a systematic experiment that is not
sufficiently established on an organographical basis.

22. Achnanthes. — Individua solitaria vel binata vel
numerosa in fascias plus minusve elongatas transversaliter
conjuncta , stipite laterali adnata.

In the want of strise three species ( minutissima , exilis,
parvula ,) present great analogy of form with the pre-
ceding. In one of these ( parvula ) there is wanting the
characteristic angular bending, for which reason it be-
comes very similar to Odontidium and Diadesmis. The
other ten species ( striata ) differ only by very slight
characters from each other. Besides the organic differ-
ence between the two secondary surfaces, the constant
median aperture of the inferior or ventral, (Ehrenberg,)
and besides the process of du plication, which may be
studied, in all its details, in the Achnanthides better than

408

ANIMAL NATURE OF DIATOME.®.

in any other Diatomese, the stipes truly merits particular
consideration. Its constant collocation proves that the
Aclinanthides are, like the Surirellce, adherent by one
extremity, and the insertion ofthe stipes becomes oblique
only because the duplication always takes place on the
side of the dorsum ; that is, in other words, from the tvvo
individuals which are formed at the expense of the first
one, only the one corresponding to the dorsal surface is
ultimately separated ; and the same thing occurs wit.h
those that follow. As to the internal substance, Ehren-
berg says it is divided into many rounded portions,
which in A. longipes collect in the middle, like rays,
around the median aperture. In the A. salina (A. bre-
vipes , Ehr.) the same Ehrenberg describes this substance
as separated, from the first, into four lobes, which
finally divide and resolve thcinselves into moveable cor-
puscles.

23. Cymbosira. — Individua vel solitaria vel binata, '
stipitata ; in serics isthmo gelineo concatenato .

The essential character by which the single species
{C. Agardhii) generally differs from the Achnanthides
seems to indicate that in this the duplication happens
promiscuously either in the inferior individual or the
superior. The series consisting of solitary individuals
may be considered as originating from the successive
duplication of only one superior or dorsal individual.
The same may be supposed of the series of geminate
individuals alternately conjoined; but when the con-
juuction is unilateral the supposition is admissible that
after the first duplication is accomplished the second is
effected in an inferior individual, and repeated in the
inferior one through the successive links of the chain.
We may notice that the dimensions vary greatly in
different individuals, but are constantly the same through
all of one series. The specimens from Cayenne, para-
sitic on Polysiphonia subtilissima, (along with Podosyra
Montagnei and Odonlella polymorpha,) differ from the

ANIMAL NATURE OE DJATOMEJä. 409

Adriatic specimens by their larger curvature and more
decided transverse strise.

The fainily of Achnanthese is also distinguished from
all others by the coraplicated structure of the shield.
The primary surfaces, Kiitzing says, are formed of tliree
pieces, two lateral, transversely striated, and one median
traversed by two longitudinal striae witli terminal per-
foratious corresponding to their extremities. Hence
every individual will appear to be formed of eight valves.
To me it appears, on the contrary, that these transversely
striated lateral portions can by no meaus be distin-
guished from the secondary surfaces ; there being neither
angle nor joint to indicate the supposed distinction.
I do indeed find that the two halves of each lateral
surface are inclined to each other like a roof, and they
easily become detached one from the other, thus con-
stituting, together with the two primary surfaces, at
least in appearance, six valves. The internal funnel.
' shaped appendage which accompanies the central per.
foration of the inferior valve, is really very remarkable.

24. Cymbella. — Iiidividua solitaria vel geminata ,
libera ( nec adnata nec inclusd), curvata incequilatera ;
latere primär io uno (interiori ventrali) angustiore, altero
{exteriore, dorsali ,) latiore; lateribus secundariis cequalibus
( transversim striatis) ; aperturis mediis viarginalibus ap-
proximatis.

In general form, in the parellelism of the curved
primary surfaces, in the inchnation of the secondary
surfaces, in the trapezoidal transverse section, and in the
mode of attachment when parasitic, ((7. Pediculus ,) the
Cymbella; are very similar to the Epithemice. They
differ essentially from these by the two perforations
placed in the border of the inferior side of the lateral
surfaces, and therefore sufficiently near each other to
seem united into one when placed obliquely. They have,
moreover, a distinct aperture at each extremity. The
difficulty of making out these characteristic perforations

410

ANIMAL NATURE OF DIATOMEiE.

in the minuter species renders uncertain the generic
arrangement of some among the fifteen species enu-
merated by Kützing.

25. Cocconema. — Individua ut in genere prcece-
denti sed stipitata, stipite ex uno apice cymbellarum
crescente.

Without concerning ourselves with the generic value
of the character which is wanting in six of the eleven
species ascribed to Cocconemce, it is most interesting to
consider that whilst some Cymbellce adliere parasitically
to submerged bodies by their ventral surfaces, like Epi-
themice , the Cocconemce, again, adhere with a stipes by
one of their extremities. Are we hence to infer that the
adhering side may be either one of the primary surfaces
or one of the secondary (Cocconoideae) or finally one of
the extremities ? Or must we regard adhesion as a
primary character in judging of the organ ographical
correspondence of the various surfaces and different
typcs, and make other characters subordinate to it, such
as the one derived from the division which sometimes
takes place in the direction of that surface, sometimes
transversely to it? Again, admitting the first case, ought
we not, at least, to ascribe to this character a value
superior to that of the presence or absence (at least when
they arc doubtful,) of the central and terminal apertures ?
Or, finally, that adhesion of the only species of Cymbella
which is said to be parasitic (C. pediculus), is itnot merely
ventral in appearance, as seems sometimes to be the case
in certain Achncmtliides ?

26. Syncyclia. — Individua cymbelliformia transversim
in fascias circulariter in curvas connata , in substaniia
gelinea molli amorpha nidulantibus.

The genus Syncyclia [S. salpa, S. quarternaria ) repre-
sents, among the Cymbellem, the genus Eumeridion in
the order Astomaticse, the Epithemia costata in the
family of Eunotiese. Whenever the lateral surfaces are

ANIMAL NATURE OF DIAT0MEJ3.

411

inclined to each other, by the different extension of the
two primary surfaces, the associated series must be formed
circularly, as it is effected in a circular or at least a
curved manner in the plane of the associated series, when-
ever the primary surfaces are cuneate, and the con-
vergence of the lateral surfaces is in the direction of one
extremity ( Meridion , Odontidium, Diatoma.)

27. Encyonema. — Cymbellce longitudinaliter seriatce
tubo geline o simplici tenerrimo molli inclusce.

The gelatinous tube vvithin which the Cymbellae
referred to this genus are included (E. paradoxum , E.
prostratum ,) might pe.rhaps be compared to the stipes of
Cocconema, and thus serve to explain its origin. We
must, in that case, suppose the stipes to represent the
gelatinous sac within which the Cymbellae is developed.

In all the family of Cymbelleae ( Cymbella , Cocconema,
Syncyclia , Encyonema ,) we may repeat what has been
said before of the genus Cymbella, since the distinction
of genera is based upon characters merely accessory.
We may here refer to what Kützing says of the internal
substance. This is disposed in two laminae extended
upon the lateral surfaces, which present a median notch
( emarginatura ) corresponding to the convex side, and
are collected together into a very fine transverse mem-
brane.

28. Sphenella. — Individua solitaria, cuneata, libera,
nec aßxa, nec stipitata, involuta.

The Sphenella; only differ from Naviculce in tlieir
cuneate form, perfectly similar to that of Meridion, by
which, too, the associations (S. angustata ) become flabel-
liform and quasi circular ; but they differ from Meridion
by the central Perforation of both secondary surfaces,
and by the interruption of the transverse striae of the
same surfaces, (S. glacialis, S. vulgaris.) Ilcnce there
remains a greater similitude to the Navicidce, and the
distinctive characters are so slight, that the generic

412

ANIMAL NATURE OE DIATOMEJ3.

arrangement of at least two species (S. P parvula, S. ?
Lenormandii ,) out of tlie seven remains uncertain.

29. Gomphonema. — Corpuscula silicea a latere pri-
mario cuneata, basi affixi vel stipitata, stipite yelineo.

As Cocconemce from Cymbellce , so Gomphonemce only
difter from Sphenellce by the stipes; on which account
species are now referred to Gomphonema wliicli formerly
belonged to Sphenella (G. olivaceum). And with respect
to the whole thirty-three species of Gomphonema , it is
still doubtful whether tliey ought not rather to be placed
among the Sphenellce. lndependently, therefore, of the
value which the presence of the stipes may have as a
generic character, it is important to consider it in an
organographical point of view. Kützing supposes the
Gomphonemce to be at first free, like Sphenellce, and that
afterwards they affix themselves by means of the (gela-
tinous) substance of the stipes, which in his opinion they
secrete from the inferior extrem ity. No direct Observa-
tion confirms this hypothesis, and it is at least as just to
admit the other, that the Sphenellce are at first attached,
like the Gomphonemce , and afterwards become free.
Ehrenberg says, that the Gomphonemce can become free
and again adhere. The circumstance of a tubulär cavity
through which this stipes runs, according to Kützing,
and the laceration that is produced in this tube, when in
the act of duplication the two new individuals separate
from each other, effecting a dichotomy, if by any means
it could be reconciled with the idea of a simple secretion,
certainly agrees better with the supposition that the
stipes in Gomphonema, like that of Cocconema, may be
compared with the tube of JEncyonema, and, like that,
capable of its own proper growth, and therefore endued
with life. But it remains to be proved that the stipes
can divide itself from above downwards, to produce the
dichotomy, as maintained by Kützing. There is little to
be remarked on the form of Gomphonema. The primary
surfaces are constantly cuneiform-trancate. In one only

ANIMAL NATURE OE DTATOMEiE. 413

( curvatum ) they are curved. The secondary are obovato-
acute in the first eleven species; elliptico-lanceolate in four,
( dichotomum , affine , intricatum, lanceolatum ;) in all the rest
they are distinctly capitate or more or less panduriform.

30. Sphenosira. — Individua in filum complanatum
anceps rectum arcte conjuncta, a latere secundario apicibus
incequalibus ; apertura 7tiedia distincta.

Kiitzing hiraself observes, that the single species of
this genus (S. catend) belongs rather to the genus
Diadesmis of the following family, because, although the
apices of the secondary surfaces are unequal, it wants the
constant character of all Gomphonemeae, the cuneiform
primary surfaces ; whilst we see represented the associated
form of Sp/ienella angustata.

The Gomphonemeae, according to Kützing, ( Sphenella ,
Gomphonema , Sphenosira) are related to the Licmo-
phoreae in form and development. They differ by the
absence of the vittse, and the presence of a central Per-
foration in the lateral surfaces. The internal substance
is disposed in two laminae extended over the primary
surfaces ; in Opposition, therefore, to what takes place in
the preceding family of Cymbelleae. Ehrenberg notices,
also, colourless vesicular spaces. We must not omit,
that even in Gomphonemeae the primary surfaces are
traversed by the usual two longitudinal striae, terminating,
superiorly at least, in distinct apertures.

31. N'avicula. — Individua singularia libera, regu-
laria, rectangula, prismatica ; apertura media rotunda.

ln this genus, the richest of all in species, and the
type of a family the richest of all in genera, from which
sorue have adopted the name Naviculeae rather than that
of Diatomeae for the entire dass, the constant character
is the symmetry of each pair of surfaces as well as of both
extremities. We have seen this character, witli a few
exceptions, in the family of Fragillarieae, and still more
in the Surirelleae. ITence it follows, that in some genera

414 ANIMAL NATURE OP DlATOMEiE.

(. Denticula , Synedra,) or in some species {Surir eilet) of
tliese we must resort to other cliaracters to establish the
distinction, more especially as the forms are frequently
very similar. This essential character — that of the entire
family — is the presence of a central aperture in both the
secondary surfaces. Butthis character is wantin g in some
species of Navicula ( Oxyphyllum , vulpina, &c.) and in one
of the subsequent genera ; and Ivützing observes that it
is often very difficnlt to discover the aperture on account
of its minuteness, and that it is absent in some, tliough
evident in others of the same species. Therefore, without
attempting from this to argue in Opposition to the
organ ographical importance of the character itself, it is
certainly of diminished value systematically considered ;
and Kützing acted prudently, in doubtful cases, by
regarding evident afhnities of figure, so as not to separate
similar objects from one another. Kützing divides the
large number of species (137) into six groups, according
to their shape ; — lanceolala, oblonga l. elliptica, gilben ,
constricta s. nodosa, lun atce, sigmoidea. The greater
number of species belonging to the first section ( lanceo -
lata ) have precisely the form termed navicular, the
primary surfaces linear, and the secondary longato-
elliptical, vvith their apices more or less acute. We have
seen above that the first section of Synedra ( Scaphularia )
have this same form ; and after the admission of Kützing
himself and his example in respect to one species, it is
truly surprising to see the Scaphularia and Navicula
lanceolata generically separated from each other. Some
of the species referred to this first section show a gradual
transition to the different forms of the succeeding sec-
tions. But in all these we find species described and
figured in Kiitzing’s work so similar to one another, that
there occurs a well-grounded suspicion respecting the
propriety of the distinction. And here it is proper to
observe, that in Diatomeae, more perhaps than in any
other dass of organised beings, it is difficult to pronounce
a certain decision on the value of cliaracters. In animals.

ANIMAL NATURE OF DIATOMEiE.

415

as well as in plants, the multiplication by reprodnction
is accompanied frequently by alterations more or less
important in size and external form. When, again, the
multiplication is effected by simple division, both the
forms and dimensions remain constant. Nor will we here
enter upon the difficult question that relates to reproduc-
tion ; neither do we intend to dehne in what this differs
from simple division, though a division it certainly is. In
the Diatomeae the distinction is easy. In these a repro-
duction certainly takes place, since mixed among the
larger individuals of every species we often see some
smaller, some very small, and others of every intermediate
size. But their enormous abundance seems to proceed
from division (divisione) rather than doubling ( dimezza -
mento). Now, in doubling (dimezzamento), the forms
and dimensions (of the secondary surfaces) continue per-
fectly equal. Hence that wonderful uniformity in myriads
of individuals which present themselves to our observation,
all of which, perhaps, were derived by successive partition
from a single one. Hence the natural tendency that
must be feit by every observer to distinguish more spe-
cies when, among these individuals mathematically equal
to one another, he sees some rather different in form and
dimension ; or when he sees other thousands of indi-
viduals differing only by slight conditions from the
former, but all precisely equal one to another. If, again,
he then happen to meet with forms mingled among
them, different but in degree, and which successive ob-
servation proves to belong to the same species, he reflects
upon the difference that prevails among them, as well in
Proportion as in dimension, and he easily believes, again,
that these differences are really greater than those fre-
quently proposed to distinguish species. Kützing, for
example, gives us four figures of Navicida viridula,
(PI. iii, fig. 44 ; 1, 2, 3, 5, 6 : Fl. iv, fig. 10, 15 : PI. xxx,
fig. 37.) These he properly refers to the same species,
although the proportion between the breadth and length,
the degree of convergence of the sides, and the ventral

416 ANIMAL NATURE OE DIATOMEiE.

prominence, are certainly unequal. If we compare the
three figures of Navicula nodosa (PI. iii, fig. 57 ; 1, 2, 3,)
we shall see in one of fliese (2) a median enlargement
that is wanting in the others. Certainly we find minor
differences when comparing species with species. If we
look to dimensions, it is only in some species that
Kützing observes and figures the two extremes in size,
as, for example, in iV. amphisbaena, (PL iii, fig. 42.) For
the rest he contents himself with noting the largest size.
But Ehrenberg observes also the smallest extreme that he
meets with, and delineating exactly the intermcdiate
forms, puts in evidence the specific characters that rc-
main indcpendently of age and degrees of development.
Treating of the dimensions of these microscopic beings, I
cannot avoid making a few observations. Mohl has
discussed the methods of micrometry in a profound
manncr, showing the comparative degree of accuracy to
be attained by them. From that inquiry it appears that
the camera lucida is the most exact and safest of all ; I
, have found it more convenient than any other. Taking
a glass micrometer (by Plössl) in which a millimetre is
divided into 100 parts, I copy the image of it by the
camera lucida, repeating the Operation many times to
ensure the exactness of my copy. Thougli executed with
an excellent machine, the diamond-marks are never per-
fectly equidistant, and are always too broad to exclude
sliglit inaccuracies. On this account many trials are
required to obtain a sufficient approximation. From this
copy I can ascertain with precision the amplification
obtained, which is always relative to the vision of the
individual. Whenever I wish to detennine the size of
an object, I copy the image with the same combination
of eye-glass and object-glass, with the same camera
lucida, at the same distance ; and measuring that upon a
graduated scale, I obtain the dimensions sought for by
an easy reduction. To abridge and facilitate the inquiry,
I construct a decimal scale on a copy of the micrometer ;
upon this I can draw the divisions, if the magnifying

ANIMAL NATURE OE DIATOME.E.

417

power do not exceed 600 diameters, and by causing the
inmge from the camera lucida to fall upon it, I have its
measurement immediately taken. I have constructed
one of these scales for every combination of my micro-
scope, and thus by a simple application of the camera
lucida, I can measure every object without at all changing
the conditions of the observation. I dwell upon the
metliod I pursue in my microscopical researches, to prove
tliat I devote to it scrupulous accuracy. The screw
micrometer also gives millimillimetres, and by the addi-
tion of a nonius even decimillimillimetres ; but besides
tliat it is inconvenient to keep it applied to the plate of
the stage, and that there is great loss of time and inter-
ruption of the observation in applying it when its use
is required, it has always the great inconvenience of waste
of trouble. In ten observations witli the screw micro-
meter, we scarcely find two that perfectly agree. Witli
the camera lucida one only is sufficient. I think it
unnecessary to bring arguments against the metliod
of applying a glass micrometer over every object we
wisli to measure. Still the plan of a micrometer fixed
in the eye-glass, and previously corrected by examining
another micrometer as the object of observation, pos-
sesses great convenience, thongh not perhaps scrupu-
lous accuracy. But we have not merely to measure the
objects we are about to describe ; we must also dehne
that measurement. It would seem so simple a tliing for
all to use the same Standard, and there is so much con-
venience in the metrical measure and decimal notation,
that it excites real wonder to see how prevalent among men
ol Science is the habit of preferring the duodecimal mea-
surement peculiar to every country, and expressing that
in vulgär, not decimal fractions. The evil would be less
were any one (Standard) adopted, constantly used, and
dehned. But the matter is worse than this. Ehrenberg
speaks perpctually of a line, without stating the Standard ;
at the same time he gives its equivalent in metrical
admeasurement, and from this it appears that his line is

27

418

ANIMAL NATURE OE DIATOME/E.

equal to two millimetres. This line is one peculiar to
kimseif ; for the line of Englisli measure, which is the
smallest of all, exceeds two millimetres in measurement.
Kiitzing makes use of a linear measure Avith the same
notation as that usecl by Ehrenberg, — three small marks,
which usually indicate the millimetre, to the right of the
cipher. It would appear that he intends to speak of
•the same conventional line; at least I arrive at this
conclusion from the following comparative table of the
extreme length of some species of Navicula, deduced
from direct observation, from the cipher of Ehrenberg
and that of Kiitzing, on the double supposition of the
line being conventionally equivalent to two millimetres,
and to the line of the Parisian incli = 2*707 centim., and
from Kützing’ s figures.*

Navicula ampbisbccna
Elireuberg,

Kiitzing, 2'8'"

Kützing’s ligure, 0-021 (^?)
Navicula cuspiduta
Ehrcnbqrg,

Kiitzing, ,:V" .

Kiitzing’ s ligure, 0-0212° (lf8)
Navicula appendiculata
Kiitzing, A .

Kiitzing’s figurc, 0-0093° (jf8)
Navicula viridula
Kiitzing,

Kiitzing’s ligure, 0-0102 (tf-)
Navicula gracilis .

Kiitzing, 5V"

Ivütziug’s iigure, 0-0207 (if)
Navicula major
Elirenberg,

Kiitzing,

Kütziug’s figure, 0-058 (qü)
Navicula obloncja
Ehrenberg, Vl"

Kiitzing, TV"

Kiitzing’s ligure, 0-0166 ($S)

0'070 millim.
0-100

0-076—0-101

0-050

0-070

0-133

0-087—0-117

0-0576

0-027

0-037—0-050

0-022

0-017

0-062—0-081

0-0157

0-051

0-076—0-101

0-010

0-235

0-333

0-222—0-300

0-130

0-135

0-166

0-180—0-216

0-110

It results from this table that the ciphers of Kiitzing
express, in fractions of a line (equal two millimetres),

* In the present translation the dccimal numbers indicate millinictcrs or
parts whcn not otherwise niarkcd, and parts oi a line arc given. in common
fractions witk the sign — En.

ANIMAL NATURE OF DIATOMEiE.

419

measurements in general a little exaggerated; not so
mucli, however, as those of Ehrenberg ; and the figures
(in Kützing’s plates) are rather below the truth, which
we may explain on the snpposition that for the sake of
economising space — a bad economy — he has not chosen
to figure the larger individuals. I may add, by way of
confirmation, the measurement of the striae which mark
the shields of every species in constant proportion. In
the JV. viridis, (the viridula of Ehrenberg, not of
Kiitzing,) Ehrenberg states that 13 — 15 striae are com-
prised in ^ of a line, and Kiitzing 12 — 14. I find

seven of these striae constantly in a centimillimetre, 70
in a decimillimetre, and then with a power of 68G I
always find 0’00098 met. between one stria and another,
with the utmost exactness. Having directly inquired of
Kützing himself, he politely told me, in reply, that he
made use of a micrometer by Plössl, marked npon glass,
in which the Paris line is divided into thirty parts, and
that he placed liis object npon this micrometer whenever
he wished to measure it. At the same time he favoured
me with a copy of his micrometer magnified 100
diaraeters. Now in this copy every division, said to equal
of a line, is 0‘00498 met. ; hence such a line would be ==
0 00149 met., or something more than half the measure of
the line of Vienna, which is 0-002638 met. Einally, I can-
not quit the subject of dimensions without making another
observation. When we examine many individuals of the
same species, we find both large and small in the process
of deduplication. And we find many of the same size col-
lected together whenever this is the case. ldence it seems
that deduplication may occur at any age. And it seems
to me that the greater the dimensions, the less frequent is
this process; and I never saw the largest species doubled.
It is a question, Avhen does this process ccase ? Is it only
the larger individuals, in which no division takes place,
that propagate their species by true reproduction ? or are
some individuals destined from their earliest origin to mul-
tiply by deduplication and others by reproduction ? This

420

ANIMAL NATURE OE DIATOMEAL

is an inquiry that refers as well to Ncivicula as to all
tlie other Diatomeae, and we liave noticed it already
when treating of Cyclotella .

The forms of Ncivicida of the tliree following sections
( elliptica , gibba, nodosa,) greatly resemble those of the
Surirella, differing only by the median aperture. In-
stances of vittae occur in N. paradoxa.

The two species referred to the section lunata belong
to two types entirely different. The one (N. ? genufiexd)
has the two primary surfaces curved, and is a true
Achnanthidea without a stipes • the other, again {N.
lanata), has the secondary surfaces curved, and hence
has analogy only to those Sgnedra which, exactly under
tliis point of view, wc liave compared to the Emiotia.

The sigmalella, or sigmoid Navicula, to the curvature
of the secondary surfaces which we see in some Sgnedra,
unite the habitual lanceolate form of the Ncmicula, in
which all the eleven are very like each other. The
greatest difference is that presented by the primary sur-
faces, which are either lanceolate also, or linear.

Now, considering the Navicula collectively in an
organ ological view, we find, especially in the larger forms,
very important conditions. Along the primary surfaces
run two lincs or small canals, terminating at their extre-
mities in distinct foramina, as we liave already found in
all the preceding families. And it is around tliese fora-
mina that the valuablc observations of Ehrenberg on
N. major. ( viridis , Ehr., not Kützing) demonstrate the
currents produced in the ambient liquids, flowing as if
they issued by one extremity and entered by the other.
In each of the secondary surfaces are tliree ample perfora-
tions, one in the centre and two at the extremities; and,
projecting from the latter, soft bodies, which Ehrenberg
supposes analogous to feet, and subservient to motion.
And it is also in the before-mentioned species that
Ehrenberg saw clearly the ingestion of incligo, and indis-
putable movements in the internal organs “connected
(witli the body) by an irritable hyaline jelly, hence offen

ANIMAL NATURE OF DIATOMEiE.

421

exhibiting a tremulous motion.” Whoever has observed
many living Ncivicidce may yet, even after ]ong study and
persevering laborious examination, find himself obliged to
confess, as I do confess, inability to decipher the complex
Organisation ; but he may also declare, conscientiously,
that he has seen, in these, numerous phenomena perfectly
analogous to those presented by an im als, and to which no
vegetable ever presents any similar.

32. Amphipleura. — Individua singularici navicidaria
prismatica longitudinaliter sulcata, apertura media nulla.

Kützing observes that mere regard to similarity of form
caused tliis genus to follow the Naviculm, though the
want of a median aperture excludes it from the Navi-
culese. He might have said the same of some Synedrce.
It is a circumstance wortliy of remark, that on account
of the two projecting lines of the secondary snrfaces, the
division cannot take place without a species of reduplica-
tion. The one of the tliree species which is sigmoid
{A. rigida ) is curved on the primary snrfaces, and under
a double aspect manifests an analogy (not an affinity)
with the Achnantheae. Although the central perfora-
tions are absent, the terminal ones seem to reuiain in the
Ampldpleurce.

33. Ceratoneis. — Individua navicularia libera sin-
gularia rostrata, prismatica, quadrangula ; apertura media
distincta, ierminalibus nullis.

The rostrum only, Kützing says, distinguishes tliis
genus essen tially from Navicula. The first species ( C .
laminaris ) difiers but very slightly in form from some
Naviculm, (/V. cuspidata, N. rostrata,) but if the terminal
apertures be really absent in tliis and present in the
otliers, the organographic difference is great. Of the
other four species, one is sigmoid, ( C . Fasciola,) one
contorted and spiral, (C. spiralis,) and two merely arched,
(6'. Closterium, C. Arcus). But in the last the symmetry
of the primary snrfaces is remarkable, whence tlicre

422

ANIMAL NATURE OE DI ATOMEN.

results a decided analogy to the Epithemia, whilst the
resemblance to the Ächnantheae, observed by Ehrenberg,
is not apparent ; and I said to the Epithemia rather than
the Cymbelleae because neither Ehrenberg nor Kützing
take any notice of a median aperture on the lateral
surfaces ; with this we are not to confonnd the umbilicus
projecting from the ventral surface.

34. Stauroneis. — Individua libera , singularia, navi-
cidaria; apertura media transversal!.

The numerous species (34) of this genus, divided into
three sections laves , {genuina,) punctata ( Utictoneis )
striata ( Slauroptera ) do not cliffer from Navicida except
by the transverse direction of the aperture, a condition
on whose organographical value we cannot pronounce
any judgment, not knowing the office of this aperture,
nor its relation to internal structure. Still it is right to
observe that in many spccies it docs not seem to be the
aperture itsclf that is placed transversely, but rather the
depression, at the bottom of which is found a round
Perforation, as in Nctvicula, and, as in tliese, there is a
sort of funnel Stretching into the cavity, which becomes
visible when we look in front of the primary surface.

35. Ampiiiprora. — Individua libera, singularia, aper-
turis terminalibus binis mediis, ncc marginalibus.

Erom the figurcs of two out of three species, which
Kützing describes in this genus, it appears to me that
we rnay believe the two terminal apertures constituting
the essential character of this genus, to be nothing more
tlian the usual minute foramina which serve to terminate
the two longitudinal lines or canals that traverse the
primary surfaces of almost all Navicula. Nor perhaps
are central apertures wanting in the lateral surfaces ;
but tliese are seen in profile in the figurcs referred to.
The so-called wings, ( ala ) or projections, belong, therefore,
to the secondary surfaces, and constitutc the only dis-
tinctive character of the Ampiiiprora.

ANIMAL NATURE OF DIATOMEiE.

423

36. Amphora. — Individua libera, singulär ia, apertuns
mediis binis lateralibus, terminalibus nullis l. obsoletis.

The Amphora are Cymbella with primary surfaces
equal, and secondary surfaces symmetrically convex,
instead of plane and inclined. We have yet to learn
whether the two median lateral perforations exist on one
part only or both. In the first case the analogy would
be complete ; in the second, every Amphora might be “
called a double Cymbella . And indeed the two indivi-
duals into which every Amphora divides itself, by de-
duplication greatly resemble two Cymbella. Yet perhaps
this resemblance is only apparent. In the Cymbella there
is one primary surface, the dorsal, which forms the
convexity. Again, in the middle of the Amphora the
convexity is itself referable to that one of the secondary
surfaces which remains. The Cymbella, in subdividing,
give origin to two complete individuals. The two indi-
viduals proceeding from the division of the Amphora are
wanting in one of the two lateral convexities ; their lateral
surface, of new origin, ought to become convex, like the
other. In the Cymbella there occurs a simple division
or deduplication ; in the Amphora the division or dedu-
plication is succeeded by a species of reduplication. It
results, from this conformation, that in the Amphora the
navicular figure is only apparently similar to that of the
Navicula. The one is navicular in the secondary surfaces,
the other in the primary, because of the prominence of the
secondary. The division of Navicula is parallel to the
elliptical or rhomboidal surfaces; in the Amphora it is
vertical to these (surfaces). I therefore absolutely excludc
the A. atomus from this genus, as it is a Navicula or a
Synedra. The doubt raised by Kützing as to the
A. elliptica appears a certainty to me ; no central apcr-
ture in the primary surfaces being admissible. On the
same motive I assert that if the A. acutiuscida do truly
belong to this genus, the figure 1 (PI. Y, fig. 32) is
incorrect, for it represents a median aperture ; and
equally so is the third figure (PI. XX, fig. IS) of the

424

ANIMAL NATURE OE DIATOMEiE.

A. hyalina, by tbe same author. In respect to the
median lateral perforations, besicles tlie already expressed
doubt whether they exist on botli tbe primary surfaces
or only on one, it is also to be observed that they are
wantin g in six, (A. veneta, A. ajjonina, A. coffeccformis

B. Fisclieri , A. acutiuscula, A. borealis,) out of tbe
eigbteen species assigned by Kützing to tbis genus.

37. Diadesmis. — Individuci navicularia in fascias
elongaias ( biconvexas ) arcta conjuncla; aperturce medice
singuläres et terminales bince distinctce.

In 1836, Kützing publisbed (Dec. xvi, n. 153) the new
genus Bracliysira : “frons minutissima constituta e frus-
tulis paralleliter et irregulariter cocidunatis .” Now, in
bis Monograph of Diatomese, be makes no mention either
of the genus or tbe species ( B . aponina ) which was
nothing more than N. appendiculata. Nay more, there
is enumcratcd among the Naviculeac tbe Brachgsira
serians of Brebisson, and Bailey’s fine obscrvation on
N. major (N. viridis , Ehr.) is suppressed, “ that it is not
rare to mect witli four, sometimes even eigbt, united
laterally.” The genus Diadesmis is establisbed, bowever,
in which tbe Naviculae are arranged in rows exactly as in
tbe species just describcd, only perhaps witli more con-
stancy and regularity. Yct tbe foundation of tbis genus
is justificd by analogy witli otber families, and by that
siinilarity of genus in tbe parallel series which perhaps
is supremely attractive in systcmatic Classification. But
independently of tbe value of tbe genus, which I do
not controvert, the organic condition of this concate-
nation in the Diadesmce and Sphenosirce seems to fur-
nisb important considerations. If tbe central aperture
of tbe secondary surfaces were really stomatic, serving
to tbe ingestion of aliment, we miglit suppose that, in
respect to tbe individuals contained in tbe midst of
tbese fasciay, that, unlike tbe terminal ones, they took tbeir
nutriment mediately. Altbough such a condition occurs
in other classes of animals, yet in our case it is purely

ANIMAL NATURE OF DIATOMEiE. 425

hypothetical. Now in Opposition to this hypothesis
Stands tlie fact of all the Diatomeae destitnte of this aper-
ture. Instead of it, we find in almost all of tliem the
presence of two terminal Perforation s of the primary
surfaces, always so situated, even in associations of
numerons individuals, that they can perform their func-
tions freely. The minuteness of these apertures would
be adapted to the tenuity of the food they were in-
tended to receive, and in i gilt, in some degree, explain
why nothing can be discerned as to the nature of this
food or the conformation of the digestive Organs, wliilst
in other Infusoria, even of smaller dimensions, the sub-
stances received can be clearly distinguished. And
altliough the terminal apertures of the secondary surfaces
may seem to belong to Organs of motion, (as Ehrenberg
lias describecl, in some of the larger species, and as appears
indicated also by the nature and direction of the move-
ments themselves,) still it is a reasonable supposition for
any one to believe that the median aperture is subser-
vient rather to the generative function.

38. Erustulia. — Individua navicularici, in substantia
gelinea amorpha nidulantia.

The only character that distinguishes this genus from
the Naviculce is the presence of a mucous envelope. In
one of the two species {F. maritima) the Naviculse arc
included in various numbers within a distinct cell.
Again, in another, {F. salina ) the enveloping mucus is
amorphous. By the same character Ehrenberg compre-
hended also in this genus that N. appendiculata of whicli
Kützing had constructed liis genus Brachysira. Organo-
graphically, the Frustulice show the transition of the free
to the included Naviculem.

39. Berkeleya. — Phycoma gelineum wolle basi
globoswn, ramos filiformes naviculis dense aggregatis
repletos emittens.

In this and the two succeeding genera ( Raphidogloca ,
llomceocladia,) there is not merely wantin g the primary

426

ANIMAL NATURE OF DIAT0MEJ2.

character of Naviculese, the central aperture, but even
the form of the sliields corresponds to that of many
Synedrce of the sections Scaphularia and JEchinaria ;
hence they seem rather to belong to the family of
Surirellese in the preceding order.

40. Rapiiidoglcea. — JPhycoma ylobomm yelineum
yiolle, intus fasciculis novicularum in ßla radicmtia
dispositis farctum .

The principal character of this gcnus is taken from the
amorphous disposition of the gelatinous substance, in
which the Naviculse, or rather the Synedrse are iinmersed.
Under this point of view the gcnus Berkeleya is inter-
mediate between the Baphidoylcea and the Homosocladia.
But it is the characteristic disposition of these Synedrse,
that whilst they are mixed together in a disorderly
manner in the preceding gcnus, and fasciculated almost
in a parallel manner in the following one, in this they
are arranged in fusiform fascisc, confluent by the pointed
extremitics. Whether we consider the first or the second
of these characters, I doubt whether we can regard them
as sufficient to distinguish the thrce genera. In one ol
the four spccies enumerated by Kiitzing {R. manipulala )
the great variety in the size of the Synedrse is remark-
able ; he says they vary from ^rd to ^th of a line, but
witli an amplification of 420 diameters he delineates
them from 7 to 25 millimetres, corresponding therefore
to 0‘OlGö millim. — 0’0595 millim.

41. IIomceocladia. — Phycoma filiforme ramosmi, ex
tubo yelineo intus fasciculis navicularum linearium
elonyatarum bacillarianum farcto compositum.

In confirmation of what has been already stated of the
difficulties attending the distinction of these genera, I
have subjoined the description of a new IIomceocladia,
which in external figure bears a striking resemblance to
the RapHdoyloece , and in its association of filaments
might perhaps be referred to the Berkeleya \

ANIMAL NATURE OE DIATOMEiE.

427

II. heloicles pumila, parasitica, adncita, filts tenuibus
e centro radiantibus, dichotomis sensim attenuatis ; syne-
dris, continue fascicidcitis, mediocribus, e facie linearibus ,
e latere oblonyo ellipticis , obtusis.

Schizonema helioides, Zanard, in litt. Ad TJloam latis-
simavi leyit Dalmatice Sandri. Frons. 3 mill. vix attingens
Rivularice adspectum omnino prcesefert. Fila ad basim
0'02 mill. vix crassa et, at in Rividariis, rotundata.
Longitudo Synedrarum 0'039 mill., latitudo 0 0043 mill.

In tliis genus, too, we may notice the greatest variety
of dimensions. Thus, for example, Kützing gives the
length of the Synedra of H.pumila , which, referred as
he states to the Paris line, corresponds to 0-079 millim.
Bnt in the figure with an amplification of 420 linear, it
only eqnals 0-016 met., and therefore corresponds to
0-0383 millim. Now I find the length to vary in my
specimens from 0-0457 millim. to 0‘078 millim., and
therefore not far from the extremes above clescribed.
This same species also presents in its thick inferior
trunk, and in the fasciculato-fusiform disposition of its
Synedrae, rather more relation to the two preceding
genera. Kützing refers my Schizonema ruorum to this
genus Homceocladia ; and justly, for it certainly does
not belong to the Schizonemce. But I think he miglit
just as properly refer it to the Berkleyce, on account
of the thickness of the walls of the mucous threads, and
the uniform confusion ( affastelmento ) of the Synedrae.
As to the dimensions of these last, Kützing says tliey
correspond to those of the Raphidoglcea interrupta ; but
this accords little with Kützing’s figure magnified 420
linear; this is 0 023 metr., and therefore corresponds to
0 054 millim.; it accords much less with the measure-
ment indicated which is = 0‘108 millim., though
the greatest length of these Synedrae in my II. lubrica
is =-= 0f04 millim. Of the seven species yet known in
this genus, two only ( anglica , Martiana ,) present mar-
ginal striae on the lateral surfaces ; this makes thern für
more similai’ to the Synedra.

428 ANIMAL NATURE OF DI ATOMEiE.

42. Schizonema. — Phycoma filiforme tenue luxum , ex
tubo gelineo ( cceloma ) ramoso naviculas abbreviatas longi-
tudinaliter seriatas fovente compositum. Spermatia
externa smplicia tubo aclnata sessilia.

The characteristic differences between this genus and
tke following one {Micromega) assigned by Kützing,
corrcspond with those proposed by Agardli (Conspeet.
crit. Diatom. 1880), in which, after rejecting the divi-
sion, previously suggested by Greville, of the two genera
Monema and Schizonema, he is iuduced by observation
to admit it in fact, obstinately insisting on rejecting it
in name. It is a lamentable thing, and the primary
source of the confusion that all deplore in the synonyms
of botany and zoology, that a mistaken vanity frequently
induces authors to maintain their own errors with perti-
nacity, and blindly to rcjcct the opinions of others.
Greville divides the Schizonemce of Agardli into two,
Monema and Schizonema ; Agardli maintains that the dif-
fercnce between tlicm rests solely on a different degree
of organic development, which it is offen difficult to dis-
covcr; therefore he recasts the two genera into one.
Somcwhat later Agardli finds certain species in which
the cliaracter defined by Greville, as distinctive of the
genus Schizonema, is evident. Wlien he discovered his
own error he ouglit to liave restored to Greville botli the
genus Monema, and the species taken from it. But it
was too liard a case ; so he turned round to establish a
new genus ( Micromega ), and refer to it the true Schizo-
nemce of Greville; tlius taking away from that author
all the species that he had judiciously divided into two
genera. The scholars blindly follow their master. The
same story, changingthe names, maybe applied to many
questions of synonyms. If the two genera be really
distinct, their names ouglit to be Monema (, Schizonema ,
Ag. and Kütz.) and Schizonema (. Micromega , Ag. and
Kütz.) ; nor can we adopt the opinien of Ehrenberg,
who, disapproving of the elision in the word Monema
(. Mononema ), as if tliere were no legitimate examples,

ANIMAL NATURE OE DIATOMEjE.

429

rejects it as erroneous, and substitutes in its stead a new
name ( Naunema ) applicable to tlie two genera which lie
rennites. It is doubtful whether the right of priority
onght to be assigned to the Hydrolinum of Link, which.
along with a Monema, coraprised an Alga ( Conferva
Hermanni), and therefore cannot be considered suf-
ficiently definite. The name Monema, which on account
of its elision should be written Monnema, applied to the
species constituted of a single tnbe including the
Naviculse, and placed in comparison with the rest,
[Schizonema), referable to the species where the single
series of Naviculse have a proper tube, and the Union of
these threads (fili) constitutes the frond, is so much the
inore exact since the second, Schizonema, both by ety-
mology and generic character of Agardh himself, as
mentioned already, ( Systema Älgarum, 1824,) denotes
this condition in a graphical manner. There is still an
important character described by Kützing in reference to
the position of the organs which he terms spermatia.
These are external in Monnema ( Schizonema ), immersed
again in the Schizonemce ( Micromeya ), as if intimately
allied to the simple or compound structure of the external
tube. Now after the consideration of such characters,
the result of an attentive examination is my conviction
tliat some species referred by Kützing to the first of
these genera belong really to the second ; and, for the
reasons just stated, these will be all entitled to the name
assigned by Kützing, whilst all the other species of
Schizonema should become Monnema, and those for
which the name Micromeya was uselessly created, should
become Schizonema.

This discordance of opinion as to the arrangement of
some species in one or other of the two genera, which,
independently of their narnes, appear so distinct and so
clearly defined, arises from the great difficulty of dis-
cerning the parallel tubes, including the particular [sin-
yole) series of Naviculse. In some species the wall of
the external tube is clearly distinct, and the Naviculse are

430

ANIMAL NATURE OF DIATOME/E.

confused within ; but in some others it seems as if
instead of a tube tliere is a mucous mass in which the
Naviculse are immersed. Then there remains a doubt
whether tlie series of these Naviculse are inclnded in
distinct tubes or in simple canals liollowed out of tlie
common mucous mass. It may perhaps be suspected
that tlie tubes visible in specimens that have beeil
moistened, do not really exist during life, and originale
in a change tliat lias takcn place after death. And it is
quite certain tliat the partial tubes waste away sometimes,
as well during life as by some alteration kappening after
death, so that tlicy appear evident in some but not in
ot.lier parts of the same specimen. The character indi-
cated by Kützing of the so-called spermatia, external
in Monncmcc ( Schizonema , Kiitz.), and internal in Schizo-
nemce ( Micromegci , Kiitz.), would therefore assist us very
much, were it constant and capable of being verified.
But Kützing himsclf only found these spermatia external
in a single species {S. tenue ). Therefore there only

remains the solc negative charactcr of the absence of
partial tubes, and whcnevcr we succeed in observing
these, the spccies must undoubtedly be referrcd to the
succeed ing genus. The absence of partial tubes, and
consequcntly confused disposition of the Naviculse, is
evident in the following species.

Monnema quadripunctatum, Grev.

Kützing changcd Lyngbye’s specific name ( Bongia
quadriqmnctata ) as erroneous, and substituted that of
Scldzonema tenellum ; establishing the lengtli of the
Naviculse, from Lyngbye’s original specimens, to be
which, in the Paris line, would equal 0 0235 millim.
But, with an amplifying power of 420, he represents it no
more than 5‘5 millim., which is equal to 001 31 millim.
Estimating this line convention ally at 2 millim., Tjyth of tliis
would be 0-017 millim., and there would be more agree-
ment. But upon an original specimen with the same
name he establishes another species {S. Ehrenhergii )

ANIMAL NATURE OF D1ATOMEJE.

431

which he pronounces synonymous with the Naunema
Dillioynii of Ehrenberg. In this he says the Naviculae
are dö'" long, or 0-0246 millim. ; but he represents
them 5 millim. with a power of 420, corresponding
therefore to 0 012 millim. Here again tliere is ground
for the same consideration, as to the slight difference
we should meet with between the size of the figures
and the admeasnrement, were the latter understood
as expressed conventionally in lines equal to two mil-
limetres. It seems to be so from the figures of
Lyngbye and Greville, but not from either of the two
species of Kützing. We are led to this supposition by
an observation of Harvey, who says, that in the M. qua-
dripunctatum the Naviculae are larger than in any other
English species, whilst by Kützing’ s description, and still
more by his figures, there would seem to be only two of
these in which the Naviculae are of smaller dimensions.
Harvey says, that specimens from Carmichael differ in
external appearance from those of Mrs. Griffiths, though
agreeing as to internal structure.

I received from Lenormand a specimen from Calvados,
with the name Schizonema quadripunctatum, in which the
length ofthe Naviculae was 0-024'".

Here it seems right to mention some different species,
all belonging to the genus Monnema.

Monnema tenuissimum, Kütz., (Schizonema.)

Having been favoured by Kützing with an authentic
specimen of this his species, I could with ccrtainty
compare it with specimens from Venice sent to me by
Kellner. I have ascertained that the length of the
Naviculae = 0 022 millim. This would agree sufficiently
with that indicated by Kützing in the description, where
he says it is döth of a Paris line, or = 0-0246 millim.
But he figures these Naviculae with an amplification of 420,
no more than 4-5 millim. which corresponds to 0-0107
millim. Here it seems, then, that the measurement
expressed in the description ought rcally to be understood

432 ANIMAL NATURE OE DIATOMEiE.

in relation to tlie Paris line, or still better, to the smaller
one of Vienna, whilst, on the otlier hand, the figure would
disagree less witli the admeasurement interpreted by the
conventional value of 2 millim., although ^th of such a
line would be equal to 0-0184 millim.

Monnema tenue , Kiitz., (Schizonema.)

As in the preceding spccies, I also find in the authentic
specimcn of Kützing, as well as in others which I have
examincd, that the size of the Naviculse corresponds to
the measure described in the definition in the line of
Paris (do = 0-027 millim.) whilst the figure givenwithan
amplification of 420 diameters is only 5 millim., and
therefore corresponds to 0-012 millim.

In this spccies Kützing observed the presence and
development of the spermatia.

Kützing observes that his S. tenue does not correspond
witli the S. tenue of Agardh, therefore he ought to have
changed the name.

Exccpt for the figure of Agardh there is reason to
suspect that it belongs to a true Schizonema , thougli
published together witli Micromegce , which combine
a coriaceous consistencc with the essential character
of jiartial tubes (‘ Icon. Algar. Europ.,’ fase, i, tab. 3.)
I find, on the otlier hand, that the Schizonema frequent
in the Lagunes of Venice, by me denominated S. aclri-
aticum , is referable to this species, and not to the pre-
ceding one, wliere Kützing would place it, and I persist
in regarding it as corresponding to the definition and
description which Agardh gives of this his own species.

Under the name of Schizonema comoides, to which it
certainly does not belong, I received from Lenormand a
beautiful species allied to the preceding, but in which
the Naviculse are constantly smaller, scarcely measuring
0’018 millim. in length. In tliese, the so-cailed external
spermatia are very abundant. This is an important
species, because the Naviculse, being very stipitate, and

ANIMAL NATURE OF DIAT0MEJ3.

433

many timcs seriate, it becomes extremely difficult to
convince one’s seif tliat the partial tubes are absent, and
the presence of externa! spermatia is really in accordance
with that absence.

From the Lenormand I also received, under the narae
of Schizonema Grevillei, inapplicable to it, another very
beautiful species, with very fine short threads, in which
the Naviculae are not only still shorter (0-017 millim.) but
also narrower (0'0045 millim.) and very acute.

Monnema rutilans , Ag., (Schizonema.)

In authentic specimens from Kützing and Jürgens, I
find the length of the Naviculae 0'025 millim., and tlieir
breadth only 0’004. Kützing says their length is or
0'027, with the usual contradiction of a much smaller
figure. In tliis the Naviculae are only 7 '7 millim., which,
with a power of 420 corresponds to 0-018.

I liave no specimens of the two forms which Kützing
considers to be varieties of the preceding, with the names
S. parvulum, S. lubricum.

Monnema Hoffmanni, Ag., (Schizonema.)

In a specimen with which I was favoured by Kützing,
I find the Naviculae 0'03 millim. long, and 0‘0064 broad,
corresponding to the description of Kützing, and larger
than his figure (9-5 millim. ^ = 0’0226).

I cannot understand why Kützing gives this form as a
variety of the preceding, whilst in external characters, in
the dimensions and the shape of the Naviculae, there are
distinctive appearances sufficient and comparable to those
by which other species are distinguished.

Monnema ectocarpoides , Mgh.

Schizonema viride, Ktz.

The enforceraent of the law of priority is, without

28

434

ANIMAL NATURE OP DI ATOMEjE.

offence to modesty, or culpable Charge of vain glory, as
applicable to matters of our own as to those of another.
Kützing, in quoting the name given to this species by
me, of necessity condemns the one proposecl by himself,
since I had previously established, though I had not pub-
lished it. He might have spared me one of the two names,
but he wonld not. In the description, he gives the size
of the Naviculse 4 of a Paris line or 0’027 millim.
But in the figure, with the same power of 420 diameters,
he delineates the Naviculse 8 and 15 millimetrcs long =
0-019 — 0-038 millim. On the other hand, I have never
found the Naviculse shorter than 0-02, or longer than
0 031, citlicr in the authentic specimen of Kützing, or
in the numerous ones from the Adriatic. The breadth
is constantly a fifth of the length.

This form, too, is regarded by Kützing as a variety of
the 8. rutilans, I know not on wliat motive.

As to Ehrenberg’s synonym ( Naunema balticum ),
quoted by Kützing; that author determines the length
of the Naviculse A of bis conventional line; equivalent to
Ai of a millimetre, or 0 0069 millim., he dravvs it no less
than 16 millim., and speaks of transverse strise, 18 to 20 of
whicli are includcd in 0‘c of a line, which, notwithstanding
the amplification of 2300 diameters and upwards, are
not to be discerned in the figure.

Monnema Dillwynii, Grev.

Kützing states the length of the Naviculse to bc ^th of
a Paris line, or 0-0318, but he figures the length as
6 millim., with an amplification of 420, whicli corre-
sponds to 0-0142. In authentic specimens received from
Berkeley, and corresponding perfectly with Kützing’s
description and figure, I find the length of the Naviculse
0 022 millim., the breadth of the primary surfaces 0-007,
that of the secondary 0-005.

ANIMAL NATURE OF DIATOMEZE.

435

Monnema /jenormandi, Ktz. in litt , (Scliizonema.)

Untier the name of Schizonema Dillwynii , Lenorraand
favoured me vvitli a Monnema from Calvados, differing
greatly from the preceding. I wrote to Kützing, who
replied that he had already created a species with the
name iS. Lenormandi, sending me in confirmation a frag-
ment of liis specimen. The Naviculae are 0 • 0 2 5 5 millim.
in length, and attain a breadth of 0-04 in the primary
surfaces, when theyare near the state of duplication.

Monnema sordidum , Kiitz., (Schizonema.)

Kützing establishes the length of the Naviculae ^
ügtli of the Paris line, or 0-0270 — 0-0225 millim., and
moreover refers to this species specimens from the lagunes
of Yenice, corresponding in all other characters, the
Naviculae being 0-0245 millim. in length, and 0'0064‘in
breadth, both on the primary surfaces, which are lineari-
rotundate, and on the elliptico-linear, obtuse secondary.
In a specimen with which I was favoured by Kützing, I
was not able to see the Naviculae clearly, but they seemecl
to me somewhat smaller, not, however, so much so as in
this author’s figure (5 millim. = 0-0119).

Monnema Grevillei , Harv.

This is one of the most instructive species, for the
Naviculae are frequently placed transversely, in such a
way as to demonstrate the total absence of partial tubes.
It is interesting also from the large size of the Naviculae,
which exhibit the process of duplication very clearly. In
these, too, Kützing saw the central aperture. In the
specimen with which I was favoured by Berkeley, under
the name of S. Grevillei (Alg. Dänin.) and S. quadripunc-
tatwn , Ag, I find the greatest dimension of the Naviculae to
be 0 034 millim. in length, and 0 0 IG in breadth, as well
on the primary surfaces, which are a sort of parallelogram
with the angles slightly rounded, as on the secondary,
that are broadly elliptico-obtuse. This differs little from

430

ANIMAL NATURE OF DIATOME/E.

the figure given by Kützing, magnified as usual, 420
diameters, which, being 13 millim. long, corresponds to
0-0309. But the dimensions given in the definition =
0'564 millim.), are much greater.

Monnema subinconspicuum, Mgh.

I found it at Trieste, parasitic upon Ectocarpus arctus ,
along with other Diatomeae.

The threads, or fllaments, are scarcely a millimetre long,
and are 0‘085 broad. The Naviculse are 0"02 long, and
0-005 broad, as well on the primary surfaces as on the
secondary.

The simplicity of the filaments had led me to believe
tlrnt tlie species corresponded to Naumena Simplex of
Ehrenberg, excluding the synonym of S. tarne of Agardh.
But the dimensions stated in the description — ^th of
a line, or 0-0052 — 0*0104 millim.), and the paucity of the
Naviculm included in the gigantic figure, seem to con-
tradict tliat association.

Among the spccies ascribed by Ilarvey to the genus
Monnema (regarded by him as a simple sub-genus), the
four following are unknown to me ; spadiceum , Grev. ;
virescens, Ilarv.; dubium , Ilarv.; crinoideum, Ilarv. Three
otliers ( implicatum , parasilicum , comoides ), belong to the
subsequent genus. The last ( prostratuni ) is an Encyonema.

Of the remaining species described by Kützing as
Schizonema, and, therefore, wanting in partial tubes, I
infer from direct observation of authentic specimens, tliat
some belong to the following genus; araneosum ; trichoce-
phalum ; Smithii; helminthosum ; scoparium ; sirospermum.
Of otliers 1 believe the saine, from the figures of Kützing,
which disclose either partial tubes or so regulär a linear
arrangement ofNaviculse as is never met with in Monnemce;
minutum , humile, floccosum , crispum, plumosum, capi-
tatum, Bryopsis, Arbuscula, hydruroides , mucosum. But
the two species lutescens and striolatu my which I do not
possess, appear to be true Monnema:.

Final ly, with respect to Schizonema illyricum , in which

ANIMAL NATURE OF DIATOME/E.

457

Kiitzing describes and figures the Naviculae as disfigured
by desiccation, I ought to state that I have observed
such Naviculae and thought them specifically character-
isticof a Schizonema, which, for this reason, 1 denominated
S. Cercaria. I have ascertained subsequently that the
Naviculae of many species undergo a similar alteration.
It takes place more frequently in the Micromegce or true
Schizonemce of that genus than in Monnemce. It ap-
pears that sometimes, perhaps in certain physiological
or abnormal conditions, the solid substance of the sliield
is redissolved. The appendages, too, with which the
disfigured Naviculae seem, in such cases, to be furnished,
are due to the partial tube, which closes upon them
(vi si addossci ), grows thin, and bursts.

43. Micromega. — “ Phycoma filiforme ramosum, tubo
communi externo cinctum, ex naviculis seriatis compo-
situm. iSeries navicularum singuläres tubulis internis
minoribus propriis ( secundariis ) vel fibris tenerrimis cur-
vatis bicrispis cinctce. Spermatia immer sa, ex dilatatione
navicularum oriunda

Brom what has previously been stated, it would seem
to be proved that, by the laws of nomenclature, we ought
to maintain the name of Schizonema for this genus : Ist.
Because Agardh established this genus (Systema, 1824)
with a definition indicating an essential generic character
which distinguishes it from the preceding, “fila fascice-
formia e filis angustioribus coadunatis composita, granula
elliptica includentibus , in quce Herum secedunt.” 2d. Be-
cause, in the very description succeeding the definition,
he insists upon this organic condition “ Compositce
( plantce) sunt epluribus individuis licet filiformibus , Herum
includentibus eadem fere corpuscula quce in Frustulia et
Meridione invenimus.” And he adds this cxcellent cha-
racter of the mode of branching, “ Ramosa cipparent, et
ab auctoribus ita describuntur, quod tantum ex fissione
Tdorum oriturF 3d. Of the tcn species ascribcd in this
work, for the first time, and all contemporaneously, to

438 ANIMAL NATURE OP DIATOMEiB.

the gerras Schizonema, four ( Smithii , corymboswn , apicu-
latum , ramosissimum ) really belong to it in the sense we
have assigned ; three, again, belongto the genus Monnema
( rutilans , quadripunctatum, Dillwynii) ; two are uncertain
( lacustre , Grateloupii) ; and one {micans) must be referred
to another genus {Raphidoglcea) . 4th. The distinction
established by Greville is well expressed in the character
of the genus Monnema, of which he takes M. qucidripunc-
tatum as a type, establishing, at the same time, as the
ty])eof Schizonemeß , the S. Smithii. 5th. WhenAgardh
(L828) discovered the stuueture of Micromega, he found
that many species, which he had formerly ascribed to the
genus Schizonema, presented the same appearances, and
he referred somc of them to his new genus in his c Con-
spectus criticus’ (1830). A greater or less rigidity of
cartilage is not a sufficient character for the distinction
of gencra ; and, in fact, we find that it lends little aid in
the determination of species, wlicn employed, as it is
by Kützing, in his subdivision of the genus Micromega
into two sections. It varies, moreover, exceedingly in the
same species.

In respect to Kützing’s definition, we have only to
notice the fine crisped fibres which he seems to have
scen encircling theseries of Naviculse sometimes, insteacl
of the characteristic partial tubes. I have never hap-
pened to sec these fibres. In every species I have been
ablc to examine, I always saw, with greater or smallcr
degree of difficulty, but always distinctly, the partial
tubes. Sometimes, certainly, I have seen these tubes
so fine, so transparent, so colourless, that, at first sight,
they only seemed to be fine margins. By the aid of
some reagent, especially of a solution of iodine more or
less concentrated, with or without the addition of sul-
phuric acid, moderating or interrupting its previous or
subsequent reaction, I have succeeded in clearly perceiv-
ing the partial tubes. I cannot suppose that the action
of these reagents would produce such a coagulation of
the surrounding amorphous mucous substance, as to

ANIMAL NATURE OE DIATOMEiE.

439

simulate the tubes themselves ; for tlie coagulation could
110t produce regulär tubes, and moreover the presence of
tliese tubes is always accompanied by a regularly seriated
disposition of the Naviculse. There can only remain
the supposition already mentioned, that besides the pre-
sence of a single enclosing tube, as in Monnemce, and
that of partial tubes, characteristic of the Sckizonemce,
there may be a tliird condition, that of a continuous
mucous substance in which single Naviculse or the
entire series of tliem may be imbedded. And this third
condition according to the.changes induced, and es-
pecially in consequence of desiccation and perhaps of the
use of Chemical reagents, may simulate either one or both
these opposite conditions. Einally, in respect to the
partial tubes, I perceive that frequently, where they
remain empty of Naviculse, they are so contracted and
contorted as to appear like nothing but the finest threacls,
which often unite the remaining Naviculse together by
their apices. And the condition I have before described,
when treating of the filiform appendages with which
Naviculse sometimes appeared to be furnished (v. S.
Ulyricum ,) is the same which is seen also in the figure
given by Ehrenberg of his Naunemci Agardhii. Therefore,
without pronouncing any judgment on the fibres incli-
cated by Kützing, I express merely my own supposition
that their apparent presence may be produced by the
partial tubes themselves.

To the organic condition of the so-called internal
spermatia, prudently noticed by Kützing, I think we
ought to refer the circumstance of the great variety of
dimensions presented by Naviculse, not only in the same
species, but very frequently in the same specimen. Varie-
ties are often met with in different individuals which an
attentive examination compels us to recognise as belonging
to the same species, while within the same thread all are
found to be equal. In the Schizonemce, on the other
liand, wefind, mixed amongst the larger Naviculse, otliers
that are less, and sonie very small, scarcely visible with

440

ANIMAL NATURE OF DIATOMEAS.

the highest powers of the microscope. It seems as if
the so-called external spermatia of the Monnemae become
detached before development, as Kützing observed, in
one species ; and tliat in the Schizonemce, on the con-
trary, these spermatia, if vve regard tlieir internal collo-
cation, become developed within the cavity of the
generating frond.

This is one of the principal reasons why the deter-
mination of species becomes extremely difficnlt. Others
may be mentioned : the immense number of species ; the
excessive Variation s of external form ; the want of agree-
ment between the measurements indicated by Kützing
in bis descriptions and those of bis figures, and tliose
also deduced by direct observation from authentic speci-
mens ; finally, the very intricate synonymy, impossible to
disentangle when we liave not before the eye, authentic
specimens of all the species, to institute a comparison.

Kützing describes and figures twenty-four witli won-
derful accuracy. To these I think tliat eighteen, ascribed
by him to the preceding genus, ought to be added ; and
not a fcw still remain to be denominated and described.
We will be as concise as possible.

Schizonema implicatum, Harv.

Micromega intricatum, Kütz.

Kützing does not give any reason for changing the
name.

Schizonema parisiticum , Griffiths.

Kützing says the Naviculm are —th of a Paris line, or
0-0235 millim. He figures the largest of them 4 millim.,
corresponding to 0‘0095. In an authentic specimen
received from Berkeley, as well as in those from
Lenormand and Brebisson, under the name of S. rutilans,
and corresponding exactly witli the first, I find the
greatest length of the Navicuhe 0 02 millim., and the
greatest breadth 0'005.

ANIMAL NATURE OE DIATOME/E.

441

Schizonema bombycinum , Kütz., (Micromega.)

Schizonema patens, Kütz., (Micromega.)

Schizonema flagelliferum, Kütz., (Micromega.)

Schizofiema lineatum, Kütz., (Micromega.)

Kützing says the Naviculae are ~ to ^th of a line in
length, or 0‘0246 to 0 027 millim. The largest of his
figures is 65, corresponding to 0 01 55. In an authentic
specimen from Spalato, with which Kützing obliged me,
and in the corresponding ones from Zara, collected by
Sandri, the extreme length of the Naviculae is 0 02,
and the greatest breadth of the primary surfaces is
0'0047 millim.

Schizonema floccosum , Rudolph, (not Kütz.)

The length of the Naviculae indicated by Kützing is
jJ^th of his line, or 0-045 millim. In specimens collected
in Dalmatia by Yidovich, which correspond with the
description, the greatest length of the Naviculae is 0 046,
the breadth of the primary surfaces 0-005 millim., in single
individuals ; the breadth of individuals very near a state
of duplication was almost double, and that of the se-
condary surfaces, which are elliptico-rhomboidal, 0-009.
In this very distinct species the extraordinary thickness
of the partial tubes is remarkable ; they are often more
than double the breadth of the Naviculae.

Schizonema hyalinum , Kütz., (Micromega.)

The length assigned by Kützing is ^ to ^th of a line
= 0'04 1 6 to 0-0338 millim. The greatest length, in plate
xxiv, is represented (äf) 7‘5, or O-OHT", and the greatest
breadth, in plate xxv, 1*5, or 0-0036 millim. In numerous
specimens from Dalmatia, transmitted to me by Yidovich,
and corresponding perfectly to the descriptions and the
figures, I find the greatest length 0 034, and the

442

ANIMAL NATURE OF DIATOMEiE.

greatest breadth of primary, as well as of the linear-
lanceolate secondary surfaces, 0’004 millim.

Schizonema tenellum , Kiitz., (Micromega.)

Schizonema Hyalopus , Kütz., (Micromega.)

Schizonema ramosissimum, Agardh.

Kützing says tliat the Naviculae are ^th of a line long,
or 0 045 millim., but he figures tliem only as 7'7 =
0'0183, and the very small 0'0024. In a specimen from
Lenormaud, and in some from Dalmatia, collected by
Yidovich, corresponding in external appearance, andother
charact.crs, witli Kützing’s figures and description, I also
find the greatest length 04)28, the breadth of the primary
surfaces (••005, and that of the elliptico-elongate obtuse
secondary surfaces 0 0064 millim.

In an authentic specimen from Charain, obligingly
scnt to me by Desmazieres, witli thename of Schizonema
apiculatwn, wliich is cited by Agardh himsclf as belonging
to S. ramosissimum, and wliich differs a little from the
preceding, the Naviculse attain 0 054 in length ; morc
frequently they are only 0*042. The primary surfaces
are linear; the secondary, elliptico-elongate, ratherlarger,
are a quarter of the length in breadth. Many smaller
ones (0 02) are mingled witli the otliers.

Under the same name of S. ramosissimum I received
from Harvey and Berkeley a species entirely different
from Kützing’s, and corresponding perfectly with the
description and figure given by Kützing of his S. strio-
latum. In this the transverse strise upon the external
surface are very evident. Although Kützing does not
state the dimensions of the Naviculse in his definition, tliose
represented in his plate, and calculated by the usual rule
as equalling half theCjndicated amplification, would be
twice as large. In our own, the greatest length is 0-018
millim., and is not quite tliree times the breadth of the
primary surfaces. In the figure of S. striolaium , the greatest

ANIMAL NATURE OF Dl ATOME/E.

443

length is 7'5 millira. (^) = 0- L8, and is almost four times
the breadth.

Schizonema setaceum, Kütz., (Micromega.)

The lengtli assigned by the author Jg to ^ of a line =
0’0467 to 0045 millim., delineated 8-2 millim. (4f2) =
0 0195.

In an authentic specimen frorn Kützing, and in those
that I refer to this species, I find the Naviculae 0-02 millim.
long, but considerably broader tlian the figures of this
author; the primary surfaces being 0‘004, and the
secondary 0'07, wlience the shape becomes manifestly
elliptical.

Schizonema aureum, Kütz., (Micromega.)

Although Kützing lias indicated no other locality than
Sidmouth, I refer to this species some specimens that I
collected at Zava, wliich correspond perfectly vvith this
author’s description and figure. The Naviculae are 0 032
millim. long, (Kützing says they are i line = 0 0338
millim.; and represents them 7 millim. 4f° = 0-0166,) and
are 0-006 in breadth of primary surface, and a millimilli-
metre more in the secondary. In this species I have
seen single Naviculae with swollen internal spermatia, as
Kützing delineates in his M. polyclados, to which at
first I thought it must belong.

Schizonema corymhosum , Ag.

Schizonema myxacanthum, Kütz., (Micromega.)

The greatest length of the Naviculae, according to the
author, jtth of a line = 0 0492 millim. (according to the
figure only 0-022). To this I believe I ought to refer a
specimen I collected at Trieste, the Naviculae of which
attained 0-05 in length, and 0-009 in breadth, as well in
the primary linear, as in the secondary elliptico-acute
surfaces.

444

ANIMAL NATURE OF DIATOMEiE.

The partial tubes are very evident, and so is their
confluence at the apex, from wliich is derived the digitato-
midtifid ramification.

Schizonema apiculatum, Ag.

The ^th of a line, which Kützing assigns as the lengtli
of the Navicula3, corresponds to 0’0492 millim. As usnal,
the figure gives a measurement of half the size. In speci-
mens from Lenormand and Brebisson, I find the lengtli
of the Naviculm 0"04 millim., the breadth of the primary
surfaces 0‘01, of the secondary 0-012, and the figure of
both perfectly corresponding with the description and the
delineation of Kützing.

Schizonema medusinum, Kütz., (Micromega.)

In specimens so denominatcd by the author, 1 find the
Naviculae 0-036 millim. long, 0-0047 broad in the primary
surfaces, and a millimillimetre more in the secondary.
Kützing does not state the dimensions ; from his figure,
I infer the lengtli only to be 0-0262, and the breadth in
Proportion.

Schizonema chondroides , Kütz., (Micromega.)

I regret that I have becn unable to study this species,
on account of the peculiar mode of prolification at the
extrcmities.

Schizonema spinescens, Kütz., (Micromega.)

Found in Yenice, by Zanardini. The Naviculae (0-042
millim. long, and 0-0062 broad,) differ little from the
dimensions indicated by Kützing Gfcth of a line), being
about twice the size of the figure (9*6 millim. T = 0 022).

ANIMAL NATURE OE DIATOME2E.

445

Schizonema albicans, Kiitz., (Micromega.)

If tlie specimens from Dalmatia, whicli I think ought
to be referred io it, really belong to this species, the
name is not well cliosen ; indeed it indicates a condition
whicli the author confesses not to be constant, (i vel
olivaceo-virescens) and whicli is common to many species
in a state of decay. Length of Naviculae 0036, (Kützing
says jLth of a line = 0*03 millim., and figures them
6 millim. = 0*0142), the breadth of the primary surfaces
04)061, of the secondary, whicli are broadly elliptical,
it is a millimillimetre more.

Schizonema torquatum, Harv.

(Micromega polyclados, Kiitz.)

It is on Kützing’s authority that I refer to his species
the authentic specimen whicli I received from Berkeley
with the name above mentioned. In this I find the
length of the Naviculse 0*03 millim., and the breadth 0*005
in the lateral surfaces, which exceed the primary by a
millimillimetre. The dimensions, therefore, (not described
by Kiitzing,) are something less than twice those of his
figure. Kützing is right in remarking that my Schizonema
nebulosum, which I erroneously considered belonging to
the genus Frustulia, corresponds to this species in the
form and dimensions of the Naviculse. Although when
dried upon paper it only forms a light cloud, yet, when
diligently examined, it proves similar in ramification to
Ilarvey’s species.

Schizonema pallidum, Ag., (Micromega.)

In a specimen gathered by me at Trieste, and corres-
ponding perfectly with the description and figures, I find
the greatest length of the Naviculac to be 0*04, whilst
Kützing says it is Jgth of a line = 0*049 millim. The

440

ANIMAL NATURE OF DIATOME/E.

breadth, both of tbe perfectly linear primary, and the
elliptico-elongate secondary surfaces is about 0’008. We
sliall find a perfect agreement with Kützing’s figure by
supposing, as usual, that it represents one half of the
indicated amplification of 420 diameters, the Naviculse
being here 8' 5 millim. long.

I believe that some specimens, also collected at Trieste,
by Zanardini, (wliich are perfectly sirailar to the preceding
in extern al appearance, but of wliich the Naviculse are
shorter and more slender,) belong to a different species,
not described by Kützing. In the one, the length is five
tiines tlic breadth ; in the other it is six times in respect
to the secondary surfaces, and more than eleven times in
respect to the primary. Length 0’036; breadth of tlie
primary surfaces 0‘00G, of the secondary, 0’0035 millim.

Schif&onema corniculatum , Ag., (Micromega.)

Although I might be supported by Kützing in the
determination of this species, and thougli my specimens
perfectly agree in external appearance with the figure
given by this author, still I cannot but confess some
doubts as to the species itself. And, in the first place,
Kützing attributes a larger size to the Naviculse than to
thosc of the preceding species. He says tliey are no less
than ^th of a line, therefore 0 054 millim., and in con-
formity to this he represents tliem ] T millim., with an
amplification one half less thanwhat he assigns tohis figure.
On the other hand, I find the greatest length 0-03, and the
greatest breadth, whether of the exactly linear primary
surfaces, or of the elliptico-elongate secondary, 0-007.
The length being rather more than four times the breadth,
the form of these Naviculse corresponds with that re-
presentedby Agardh (Icon. Älg. Europ,., tab. 4.) I find
that the figure given by Agardh himself does not corres-
pond with it in external appearance; the figure agrees
much better with the preceding species.

It is tme that we can find this form more or less rieh

ANIMAL NATURE OF DI ATOMEN.

447

in penicillate branches, which would seera to justify tbe
opinion of Kützing, who regards the Micromega penicil-
latum of Agardh as a variety of the sarae species, bnt
without noticing whether the Schizonema penicillatum,
Chauvin, should also be placed there ; but the same speci-
mens more denuded have no resemblance to Agardh’s
tigure. For this reason, before I consulted Kützing,
and before he published his work, I had given the name
of Micromega divaricatum to the one I had collected
very abundantly at Zava.

Schizonema Blgttii, Ag., (Micromega.)

The following species are ascribed by Kützing to the
preceding genus.

Schizonema minutum , Kütz.

Schizonema humile, Kütz.

Schizonema ciraneosum , Kütz.

Schizonema comoides, Ag.

I am indebted to the celebrated Berkeley for an oppor-
tunity of studying this species, and of convincing myself
of the existence of special tubes, which easily escape
observation, owing to their own tenuity and the size of
the Naviculae, whose uninterrupted series are narrowly
stipate. It is by these characters, and by the form and
Proportion of the Naviculae themselves, that I was led to
the exact determination of the species, though the dimen-
sions are very different from those indicated by Kützing.
He says the Naviculae are as mucli as Ath of a line in
length, or 0-049 millim., (and he represents it, with a
power of 400 diameters, 8-9 millim., which would be about
half the size indicated,) and I, again, found it no more
than 0-024 in length, 0-005 in breadth of the secondary
(qu. primary ?) surfaccs, and very variable in the always
broad secondary surfaces, which attain to 0"012 millim.

448

ANIMAL NATURE OF DIATOMEiE.

Schizonema floccosum, Kütz.

If, as seems probable, tliere exist partial tubes in this
species, and we ought thcrefore to retain it in this genus,
it is necessary to change the specific narae, for tliere is
already a Schizonema floccosum of Rudolphi. By the
customary laws, we ought to name it S. Kützingii.

Schizonema crispum, Montag.

Schizonema plumosum, Kütz.

Schizonema capitatum, Kütz.

Schizonema trichocephalum , Kütz.

I find a Schizonema, from Marseilles, with which I was
favoured by Solier, and in which the Naviculae are 0-025
in lcngth, to correspond exactly with the dcfinition and
the figure of lvützing. He says tlicy are as much as —
of a line = 0'0225 millira. There are evidently partial
tubes, and the figure of Kützing leacls us to suspect their
cxistence.

Schizonema Bryopsis , Kütz.

Schizonema Arbuscula, Ehrenb. (Naunema.)

Although Ehrenberg asserts that there are no partial
tubes, still he admits that this species forms a transition
to the genus Micromega. Kützing’s figure, by analogy
with other species, induces us to admit their presence.

Schizonema hydruroides, Kütz.

I cannot help observing that Kützing, the most acute
observer and most faithful painter of nature, has in this
species also clearly delineated the special tubes, though
he has placed it in the genus Schizonema.

ANIMAL NATURE OF DI ATOME.®.

449

Schizonema Smiihii , Agardh.

The testimony of Kützing, and a comparison with an
authentic English specimen, obligingly supplied by
Berkeley, convince me tliat the Schizonema whicli we
have most abundantly of all in the Lagunes of Venice,
belongs to this species. I was led away before from this
conclusion by the exclusive locality of Sidmouth, indi-
cated by Kützing, and the comparison of specimens with
whicli I was favoured by Iiarvey, of whicli we shall speak
by and by, by the difference of measurement, and the
evident presence of partial tubes. Kützing says the
length of the Naviculm is ^th of a line, or 0 054, and, as
usual, gives a figure less than half the size he mentions,
( — -1*1 millim. (^) = 0-026.) I find the greatest length
to be constantly 0-044, the breadth of the secondary
elliptico-elongate surfaces 0-012, and that of the primary
slightly elliptico-truncate 0 0 12. As to its generic Posi-
tion, 1 observe that Iiarvey places this species in his
section Schizonema , corresponding to the Micromegce of
Agardh and Kützing.

Einally, thougli incidentally, it is right to make a
remark here on the practice, with even the most con-
scientious authors, of copying references without verifi-
cation. Both Harvey and Kützing copy from Agardh
the referenceto Viva fcctida of English Botany (pl. 2101),
whilst in that classical work there is onlv the Conferva
fcetula, and the Viva fcetida of Vaucher is merely cited,
by mistake, as synonymous.

Schizonema sirospermum, Kütz., (Micromega.)

Though not appertaining to this series, I here advert
to this species, because the specimens just mentioned,
with which I was favoured by the celebrated Harvey
under the name of S. Smiihii , belong to ' it. Kützing
informed me that he had received tliem, without a name,

29

450

ANIMAL NATURE OF D1ATOMEZE.

from Ralfs, and that he had named them as above. To
him, therefore, I leave the descriptiön. Length of
Naviculae 0'0337 millim.; breadth of the elliptico-elongate
secondary surfaces as much as 0’007 ; that of exactly
linear primary surfaces 0 01. In tliis species I clearly
saw the so-called internal spermatia, in form at first
ellipsoidal, afterwards globose, varying in diameter from
0'028 to 0-05, furnished with a double envelope, within
wliich the internal granules grew gradually in size.
Similar in extern al appearance to Kützing’s hgure of the
following species.

Schizoncma helminiosum, Chauv.

The spccimen with which I was favoured by Berkeley
corresponds perfectly with the figure and descriptiön of
tliis species given by Kützing, varying a little in the
assigned dimensions of the Naviculae. Length 0 052
millim., (Kützing says T’öthof a line = 0'54 ; he figures it
IT 1^'"= o-2G millim.,) breadth of the elliptico-truncate
primary surfaces as much as O'OOS, and of the elliptico-
rotundate secondary 0’012 ; less, therefore, than one third
of the length, which is the proportion indicated by Kützing.
Tn tliis species I have never been able to see the central
Perforation with distinetness. As to the dclicately crisped
fibres, described and figured by tliis autlior, I have
assured myself that tliey are nothing more than the
margins of tliick partial tubes.

Under the same name of Schizonema lielmintosum, and
with the indication of Chauvin (Alg. de la Norm., Fase. IV,
No. 77), I received from Lenormand a Schizonema from
Calvados which differs very much from the preceding in
the dimension of the Naviculae, though very similar to it
in external appearance and in the forms of the Naviculae.
These are 0’32 long, and 0'007 broad. As in otlier
species, there are mixed among the larger Naviculae,
others smaller, some very small. Iience we may suspect
that the English species do not exactly correspond with

ANIMAL NATURE OE Dl ATOMEN. 451

the French. We are induced to form tliis opinion by
the observation of Harvey, “ The frustules are larger
than in S. Smithii , longer and blunter, double, and
rather densely set.” This is applicable to the specimen
from Berkeley, but not to this one of Chauvin, which
ought to be authentic.

Very different, both in external appearance and in the
extreme tenuity of the threads ( fili) , is another Schizo-
iiema, also from the Coast of Calvados, obligingly supplied
by Lenormand, with the name Schizonema helmintosum
var. Chauv., in which the Naviculae are 0 0185 in length,
and ff 00 6 in breadth, as well of the exactly linear
primary surfaces, as of the elliptical secondary. The
partial tubes embrace the navicular series closely, and
frequently after, when the Naviculae have escapecl,
contract into fine threads or become defonned and
wasted.

Schizonema laciniatum , Harv.

I received specimens of this beautiful species from
Harvey himself, and found the Naviculae 0‘027 long,
and 0'007 broad, in the primary surfaces, which are
almost exactly linear, and in the elliptico-rotundate
secondary 0'0065. This agrees with Harvey’s observation
“ Frustules very minute and exceedinyly numerous This
would seem to refer to a species different from that cle-
scribeclandfiguredby Kützing, with thename S. scoparium,
in which he says the Naviculae are ^th of a line in length
= 0-054 millim., and to which he assigns as an uncertain
synonym this of Harvey, and the S. Smithii of Mrs.
Wyatt, {Aly. Banm. No. 151), which, according to the
indication of Harvey, would rather seem to belong to the
one before mentioned as S. sirospermum.

Schizonema mucosum, Kütz.

From Kützing’s figure we should be induced to suspect
the presence of partial tubes in this species also. As to

452

ANIMAL NATURE OF DIATOMEAE.

tlie synonym of Agardh (S. tenue), it seems more easy
to suppose tliat some mistake may liave occurred in tlie
denomination of a specimen, thongli received from tlie
autkor himself, tlian to snspect soincorrect an observation
as would result from tlie description and figure of tliis
liis own species given by Agardh, {Icon. tab. 3.)

Among tlie species ascribed to tliis genus or sub-genus
by Harvey, two remain still to be mentioned.

Schizonema obtusum, Greville.

Schizonema Wyattice , Han.

Wc onglit, finally, to add some species which we conld
not possibly include in any of tlie prcceding.

Schizonema Stalianum , Mgli.

S. parasiticum , lubricum , viride vel viridi-rufescens,
fdis setaceis, Ion (je productis, apice attenuatis, irregula-
riter romosis, remis divergentibus brevibus ; naviculis arcte
seriatis mediocribus (0*03), longitudine latitudinem sex-
iuplo superante , e facie exade linearibus , e latere elongato
eUipticis ; parum angustioribus obtusiusculis.

Sig. Stalio sent me specimens of tliis species, found at
Lesina, in Dalmatia.

It attains tlie length of three or four centimetres, is
very mucous, and adheres strongly to paper. The threads
(Jüi) attain almost a decimillimetre in thickness near
the base. It resembles none of tlie before-mentioned
species in external appearance, except tlie S. helmintosum
var. of Chauvin. The partial tubes are very slender,
but distinct. Kützing, to whom I sent it, acknowledged
that it was new.

Schizonema papillosum , Mgh.

S. parasiticum,, pumilum, mucosissimum, viride, filis
ultra setaceis subsimplicibus vel ramulis spiniformibus

ANIMAL NATURE OE DIATOMEiE.

453

acutis ornatis, papillis minutissimis regulariter dispositis
omnino tectis ; naviculis arcte seriatis mecliocribus (0 0264)
longitudine latitudinem fere quadruplo super ante, e facie
leviter elliptico truncatis, e latere anguste ellipticis, obtusi-
usculis.

Sig. Botteri sent it from Lesina to his friencl Zanarclini,
by wliorn it was communicated to me.

It scarcely attains two centimetres in lengtli ; the
threads are about two decimillimetres in thickness, the
colour dark green. The greatest breadth of the primary
surfaces is rather less 0'007 ; that of the secondary
0 0043 ; the papillse appear hemispherical or slightly
conical; they are 0*0007 in height, and are arranged
in a quincunx.

Schizonema Corinaldi, Mgh.

S. parasiticum, pumilum, viride, filis subsimplicibus
setaceis, navicidis seriatis, minutis (0'01 6) longitudine
latitudinem fere quintuplo superante, e facie exacte linea-
ribus , e latera anguste ellipticis.

Corinaldi found it at Genoa, and Solier sent it to me,
without a name, from Marseilles.

It is parasitic, like the preceding, growing on Scaphu-
laria scoparia , or upon Polgsiphoniee, and in like manner
is about two centimetres long. The threads, slightly
mucous, are a decimillimetre and a half in thickness.
They are usually simple ; the few ramifications are short
and divaricate.

Schizonema Zanardinii, Mgh.

S. tenuissimum, pallide vir ens, filis capillaribus in ramos
arachnoideos corgmbosos monosiros sensim solutis, navicidis
laxe seriatis mediocribus (0 025), longitudine latitudinem
([uadruplo superante, e facie exacte linearibus, e ledere
ellipticis.

454

ANIMAL NATURE OF DI ATOMEÜ?.

(Schizonemci, Sp. liov. Zan. in lit.)

Zanardini found it plentifully in the Lagunes of Venice.
Form : globular tufts, of three or four centimetres in
diameter, which, dried upon paper, form an uniform spot,
in which, by a lens only, the separate threads can be
distinguished. Though Ratzing assured me that tliis
was a new species, yet by its mode of ramification it
resembles S '.flagelliferwn.

This long speciological discussion may to some appear
misplaced, or at least at variance with the proposed plan
of tliis essay, intended as an organographical and physio-
logical examination of the genera. The principal ground
of my defence is the great importance of Kützing’s most
valuable work, and the respect that is due to so great an
author. Who would dare to subject so immense a
Collection of most delicate observations to critical exami-
nation, unless he were able to counterpoise them with a
series of his own observations, if not equally numerous,
at least sufficient to prove the critic in possession of
means and practice, and diligence and honesty of Ob-
servation ? Such has been my object, and if I have erred
in any respect, for I must admit that it is easy to err in
such minute researches, I hope, notwithstanding, to have
demonstrated both the excellence of the instrument
expressly made for me by Amici, of which I am sure
that no one possesses its equal, Mohl only excepted, and
the good intentions by which I endeavour to prove my
gratitude to the most gracious Prince who bestowed
upon me so munificent a gift. I believe, too, that an
examination of various specific forms is necessary, that
we may deduce from them some considerations as to the
organology of the genus.

The presence of minute Navicuke among the larger, to

ANIMAL NATURE OF DI ATOMEN. 455

wliich we liave adverted in many species, seems to me to
prove — what miglit easily be deduced from tlie ob-
servations of Kützing — tliat tlie so-called Spermatia are
developed within tlie froncls, if we may use an expression
taken from tlie vegetable kingdom. I could never per-
ceive tbat tliese smaller Naviculse were included in
distinct tubes, or tliat they constituted an uniform series
in tbe order of their size. It seemed, rather, to be con-
stantly tlie case tliat they were dispersed through the
tubes of tlie larger ones. From tliis it seems tliat we
may conclude tliat when tlie spermatium is raature, when
its envelopes are broken up and about to be reabsorbed,
the young Naviculse, passing from tube to tube, are finally
dispersed. And continuing to supply the want of sufficient
observations by induction, we may suppose tliat these clo
not begiu to divicle until they have attained their greatest
climensions. It then becomes intelligible liow the partial
tubes originate, through the persistence of the thin external
membrane, whicli we know, by preceding observations,
manifests itself distinctly whenever the deduplication
takes place. Only we must suppose that the silica is re-
absorbed, while the membrane remains in Monnemce ,
on the contrary, it disappears. It is most important to
observe how these series of Naviculse are formed within
the proper tubes. It is, in fact, the result of observation
that their disengagement is always effected in the plane of
the primary surfaces. The series may present either the
primary or the secondary surfaces. In either case the
Naviculse may be found arranged one behind another,
either contiguous or more or less apart. They are some-
timcs imbricated with the primary, never witli the se-
condary surfaces ; and when the imbricated series is
viewed on one side, the Naviculse present themselves
with their secondary surfaces entirely free and inclined
obliquely. Therefore we must suppose, so soon as the
deduplication ( sdoppiamento ) has taken place, the two
new individuals, rotating upon one of the sidcs of their
surface of contact, as upon a hinge, represent, in some

456 ANIMAL NATURE OE DIATOMEiE.

mann er, a box wliicli opens, and the two primary sur-
faces coming into contact, tlie disengagement or Separa-
tion becomes more or less complete. If tliese deduc-
tions be legitimate, as to me they appear to be, the
result is that the snccessive growtli of the entire frond
is dne to a double element ; the elongation of each series
by incessant deduplication, and the intercalation of new
series between those that pre-existed. The comparative
examination of the extremities is important in respect
to the elongation. In various species the single partial
tubes tend to detach themselves from their reciprocal
Union, either uniformly from the base ( flagelliforme ,
medusinum, Zanardinii) , or merely towards the summit,
in a sort of fan-shape (helmintosum, lacinatum). Again,
wc find the nmltiplication of the series principally
eftected near the apices, and accomplished more quickly
from the elongation of the pre-existing ones, on which
account the extremities are 'clavate {Arbuscida, clcivaiuvi.)
Where these two processes advance, pari passu, the re-
sulting extremities are obtuse ( palens , Bryopsis , intri-
caluvi). Where the elongation of the first series always
preccdcs the appearance and formation of the new ones,
the apices are acute (_ floccosum , Kütz. ramosissimm,
Hyalopus , araneosum, Smithii, torquatum). It is cha-
racteristic, too, of soine species ( chondroides , irichocepha-
lum , capilalum, corymbosum, spinescens) , to have the
prolification terminal, which manifests a succession of
distinct pcriods of Vegetation. Ifinally, the particular
condition of the S. myxacanthum clemonstrates a contem-
poraneous elongation of the series, which the resistance
of the external envelope compels to flow towards the
apex, until, that resistance being overcome, a palmate
disposition of the branches is produced.

As to the Naviculse, we know still less of them than in
the preceding genera. Ehrenberg says that some of them
are striated, but this is not confirmed by Kützing, nor
have I seen strise in any species. Yet in some 1 have
seen the two longitudinal lines of the primary surfaces doy-

ANIMAL NATURE OF DIATOME/E. 457

wliicli are consiclered to be canals. I have not been
able to see the median aperture, wbich Kützing clescribes
and figures in some species (helmintosum). As to the
distribution of the internal substance, though nothing
positive can be deduced from the observation of specimens
dried and softened, or even preserved in alcohol, it is
yet remarkable that even in such a state it presents
different conditions that are constant in each species. In
most instances it is collected along the central part of
the lateral surfaces, so that it exposes a colourless longi-
tudinal area in the centre of the secondary surfaces, and
only the tvvo extremities of the primary surfaces are
colourless. Sometimes, too, the median line of tliese last
is colourless, because the colouring matter is lodged
(nicchiata) in the four inner angles. It is not unusual
to find it Condensed in a single central globe. In a
few species only I have seen it constantly divided into
two portions corresponding tö the extremities, whilst the
median area of the entire body of the Naviculse remained
uncoloured.

44. Dickieia. — Fhycoma foliaceum {phylloma) basi
subs tipitat um. Naviculce in membrana yelinea irreyu-
lariter sparsce.

Kützing does not describe the structure of the so-called
membrane of the only species (D. ulvacect ) of this genus,
and I am sorry that I cannot consult Berkeley’s descrip-
tion. This membrane may be formed of cells including
the Naviculse, as in Frustulite , or of elongated cells or
tubes, as in Schizonemat, or of a single capacious flattened
cell comparable to that in Monnemce ; or, finally, this so-
called gelatinous substance may be a mass entirely con-
tinuous, in wliich the Naviculse may be immersed, as
indicated by Kützing “ in der gallertartigen Haut einge-
bettete,” as we have suspected of some species regarding
which tliere secms to be a doubt whether tliey belong to
the Monnemce or the Schizonema.

The last seven genera, ( Frustulia , Berkeley a, Raphi-

458 ANIMAL NATURE OE DI ATOMEN.

Icea, Homeocladia, Scliizonemct, Micromega , and Dichiea )
constitute the group of SchizonemeEe. The substance
which surrounds and includes the Naviculse in these
genera, which seems to be the same as the peduncle in
Achnanthides, Podosirce, and many other genera, is terraed
jelly (gelinea), by Kützing, who, under this Denomination,
compares it to that of the true Algse. The observations
adduced in the preceding raemoir confirm the absence
of nitrogen, and its ternary composition. Nowwe know,
frora the observations of Schmidt, Loewig, and Kölliker,
that a similar snbstance, destitute of nitrogen, ternary,
insoluble in caustic potash, and isomeric with starch, con-
stitutes the extern al coriaceous stratum in the Ascidia,
simple and aggrcgate, and forms the gelatinous mass in
which groups of individuals of compound Ascidia are
lodged. These authors found that the presence of this
substance is a character common to all the Tunicata,
and it is supposed that 'the Doliolum mediterraneum
ought to be placed in the same family from this
character. This discovery, which I before supposed
possible, has therefore now entered the domain of Science.
As the presence of a quaternary azotised substance is
no exclusive character of animal nature, so the pre-
sence of a ternary non-azotised substance, isomeric with
starch, is no more an exclusive character of a vegetable
nature.

With respect to origin and formation of this substance,
it is undecided whether, as Kützing asserts, we are to
regard it as a product of secretion, or rather as existing
per se. All animal secretions are formed in the same
manner. The theory of Goodsir, Bowman, ITenle and
Mandl has recently received confirmation from the labours
of Lereboullet on the biliary vessels of the Aselli and
those of Gros on the production of butyraceous vesicles
on the internal surface of the mammary utricles. It is
now proved that whatsoever the animal secretions may
be, they are effectuated by a production of new cells on
the secreting surface, and the accumulation of liquid

ANIMAL NATURE OF DIATOMEJE. 459

wliich penetrates within tliem by endosmosis through tlie
double wall dividing tlieir cavity from that of the pro-
ducing cell. Wlien these vesicles become detached, they
eitlier maintain a life of their own, as in the epidermis
and its productions, or they burst and pour out their
contents. If such be the origin of the gelatinous sub-
stance enveloping the Schizonemese, we must allow that
the secerning surface is either external or internal to
some particular organ. And these little cells, invisible
from their minuteness or tenuity, may continue to live,
or at least to pour out their contents, before or after
they issue from the secerning organ. But all this is
liypothetical, and wanting in any support of observed
facts. Again, considering the history of the successive
development of Diatomacese, it is more probable to
suppose the possible permanence, extensibility, and pro-
gressive growth of one of the embryonal tunics, of which
we have numerous examples, were there no other, in all
animals that undergo metamorphoses.

The Schizonemese and the other seven genera ( ’Navicula ,
Amphipleura, Ceratoneis, Stauroneis, Amphiphora, Am-
phora, Diadesmis), before mentioned, constitute the great
family of Naviculese. The Naviculese, says Kützing, when
treating of their affinities, very much resemble individuals
of the preceding families, with which they were formerly
confounded ; but they are to be distinguished as well by
the central aperture of the two lateral surfaces as by the
regularity and symmetry both of these and the primary
surfaces. He says, on the other hand, that this aperture
is frequently absent, especially in the Schizonemese, or at
least escapes observation by its minuteness. Now I add
that we have this same regularity and symmetry of form
in the Synedrce, and, with few exceptions, in all the family
of Surirellese. So that there is good reason for inquiring
what essential character remains to distinguish the
Naviculese? The consideration before adduced with re-
gard to the origin and nature of the investing substance
in Schizonema would seem to me to furnish some reason

460 ANIMAL NATURE OE DIATOMEA3.

for bringing liitber the affixed Synedrce , in a pliysiological
point of vieWj only that tliis union would be one of
analogy rather than affinity, inasmuch as we find corres-
ponding conditions in almost all the families. It is
still true, as Kützing observes, tliat here the included
are the prevalent forms, occurring with the free and
naked forms, wliilst the linear association is only re-
presented by one genns Diadesmis, and the stipitate
forms and cateniform associations are entirely absent.
But, with respect to the morphological sjgnification of
tliis predominant inclnsion, I am far from agreeing
with Agardh and Kützing in regarding it as indicating
a higher Organisation. In the theory of Agardh, where
every inferior being represents an elementary organ of
Superior beings, the mere aggregation of many individnals,
which, taken together, form one collective individual, is
sufficient to mark a step towards organic superiority or
perfection. But wc have too many examples of similar
aggregations even in the lowest members of both organic
kingdoms to satisfy ourselves with tliis character of
complication. It is not the mere aggregation of organs,
but rather tlieir mutual concurrence in the formation
of new organic assemblages (congegni) that establishes
the superiority in plants, as well as in animals. For
tliis reason the Annelkke are the lowest among the Arti-
culata, even wliilst the number of joints, all equal to
one another, of which tliey are constituted, is indetermi-
nate. For tliis reason I believe that the opinion is well
founded which regards Synpetalous flowers as superior
in organic complication to the Dialypetalous, as the flower
in general is the most complicated apparatus of the plant,
like the head of an animal. And without wandering from
the question into extraneous digression, I shall content
myself with recalling to memory wliat I have intimated
before in relation to the involving substance, to sustain
the opinion that the included forms are to be regarded
as inferior to all the others ; and the affixed, stipitate,
and concatenated, as intennediate betwecn these and

ANIMAL NATURE OE DI ATOMEN. 461

those that are free ; which last, conditions being equal,
are superior to all the rest.

Regularity, then, and symmetry of form appear to me
characteristic of inferiority, nor do I consider new argu-
ments necessary to maintain a principle which is univer-
sally adopted in all natural classifications.

1 am sorry to repeat liere what I have said so often
already, that we are entirely wantingin true datato judge
ofthe affinities ofDiatomeae, among themselves as well as
with other beings, and of the degree of their organic
complieation ; for we are completely ignorant, as it were,
of what this Organisation is. And as to tliis, Kützing
only informs us that the internal substance, which he
terms gonimic, extends itself in a thin strip (_ fettuccia )
along the secondary surfaces, then divides itself trans-
versely in the middle, and finally contracts itself into one,
two, or rarely more globular portions {grumi). We have
already found contrary to the opinions of Ehrenberg,
some more important particulars respecting the Naviculse.
Nor have we anything different to add, generally, as to
all the family.

The Naviculese, together with the two preceding
families (Cymbellese and Gomphonemem), constitute the
group of llistomaticae, a group cliaracterised solely by
the organic condition indicated by the name, and which
we have so often found to bewanting.

The other two families (Cocconoidese and Achnanthese)
which, comprehended under the name of Monostomaticae,
constitute, in union with the preceding, the grand clivision
ot Stomaticae — appear to be much more nearly allied.
The entire System, I am obliged to repeat, is constructed
upon isolated and inconstant characters, and on that
account cannot fail to be vacillating. But it is equally
necessary to allow that, in the actual state of Science
it would have been clifficult to do better ; and we must
also regard it as a principle suggested by sound reasoning,
to attribute great importance to the presence or absence
of the central aperture in one or both of the secondary

462

ANIMAL NATURE OF DI ATOME JE.

surfaces, for that condition ought to be referred, of
necessity, to important peculiarities of internal structure.
And therefore it becomes clifficnlt to conceive hovv the
exceptions can be so numerous as to render this cha-
racter so insufficient for Classification.

The Stomaticae, together with the Astomaticae, of which
we have already spoken, constitute the great order of
Striated Diatomeae, which is proportion ally, rnuch rnore
extensive than the two following.

45. P odosphenia. — Pacilli a latere primär io cuneati
a latere secundario obovato-lanceolati, affixi. Stipite nullo
( vel obsoleto).

With this genns commences the orclcr of Diatomeae
furnished with Vittae, or internal prominences, which
dividc the cavity of the sliield more or less incom-
plctcly into distinct chambers ; and here, too, commences
the family of Licmophoreae, in which is reproduced the
cuneatc form of the Gomphonemeae. This genns repre-
sents, in the Licmophoreae, the gcnus Sphenella of the
Gomphonemeae, for, like that, it is distinguished from
other genera of the same family by the more or less
complete absence of the stipes. The obovato-lanceolate
figurc of the secondary surfaces is precisely that of the
Sphenella and of the Gomphonemeae in general. The
cuneate form of the primary surfaces is, in P odosphenia,
always more dilated at the summit and acute at the base,
so that they resemble a triangle more than a trapezium.
Of the nine species described and figured by Kützing,
only one (P. Ehrenbergii ) presents transverse striae on
the secondary surfaces. The essential character of
Gomphonemeae, the median aperture in both secondary
surfaces, is absent.

They present also the character of Vittae. But if we
carefully examine these vittae, they are merely the same
longitudinal lines which run along the primary surfaces
of almost all the preceding Diatomeae, the same lines
which in many cases are produced by distinct canals

ANIMAL NATURE OE DI ATOME E.

463

furnished with terminal perforations. And here let ns
not forget how tliese canals evidently project into the
cavityofthe Melosireae, formin g more distinct vittse than
otliers ever do ; on which account, if we ought really to
found on tliis character the distinction of Orders, the
family of Melosireae or the genus Melosira at the least,
ought undoubtedly to be referred to the order Yittatae.

46. Rhipidophora. — Bacilli a latere primario cuneati,
altero latere obovato-lanceolati, stipitati.

We encounter the same difficulty in distinguishing
Rhipidophora from Podosphenia that is experienced
when practically applying the generic distinction estab-
lished betweeu Sphenella and Gomphmema, and in all
other similar cases ( Gymbella and Cocconema, &c.) ; these
differ only in the stipes, which is very variable in length,
and not always entirely wanting in the first of these
two genera.

The large size of some among the fourteen species
enumerated by Kützing permits us to observe clearly
the conformation of the shield. Let us suppose a cylin-
drical articulation of Melosira, and so compress it unequally
on one of its sides, and in the direction of both pairs of
opposite surfaces, that the resulting form sh all be cuneate,
and the two incomplete diaphragms formed by the
internal prominence of the longitudinal canals shall
extend, like these, and lose themselves towards the pointed
extremity which forms the base. Such is the structure
of Podosphenia and Rhipidophora. Yiewed on one side,
that is on the lateral surfaces, they present an obvate
arch ( fornice ) marked on the periphery of the surfaces
themselves. And the margin of tliis arch is thickened
by the presence of the canal, which, seen in front, presents
in the curve its brightness, with an appearance of
Perforation.

It would be important to ascertain how the dedupli-
cation takes place. Whenever one of the frustules,
(Bacilli) separates into two, one of the vittae previously

464

ANIMAL NATURE OF DIATOMKJE.

existing remains, and a new one appears in the in-
ternal side. Does the formation of the new vitta

precede or follow the median deduplication ? I
have not made such observations as enable me to
decide, but it seems to me that the former is the
case.

And the distribution of the internal coloured substance
bears a great resemblance to that of Melosirce , especially
in a state of dcsiccation.

As to the stipes, as well in this genus as the next one,
I have to repeat what has been said of Cocconema.

47. Licmophora. — Bcicilli flabellati a latere pri-
mario anpuste cuncati , altero latere lineares basi et apice
rotundati. Slipes crassus rigidus.

The resemblance of this to the preceding genus is only
apparent. But a true affinity connects Licmophora to
Sgnedra , from which it only differs by that character
which, though rcgarded as essential to the Meridiese is
found very inconstant in Eragillariese and reappears in
many speciesof Surirella. The vittaß, in Licmophora, are
not to be compared vvith those in lihipidophora. Tlicy
are nothing more than the usual longitudinal canals
projecting into the cavity, by which the apparent pcr-
forations or sections of their cavities appear very near
the margin of the summit. The distribution of the in-
ternal coloured substance is different from that in the
two preceding genera, and greatly resembles that of
Sgnedra.

If we compare these with the sections Tabularia
and Grallatoria, we cannot at all recognise the alleged
affinity.

Bor this reason, I think we ought to exclude the
Licmophora divisa from this genus, and place it in the
preceding one.

The four species that remain, {fulgens, radians,ßabel-
lata, Meneghiniana ,) though described and figured by
Kützing with so much diligence, are very difficult to

ANIMAL NATURE OF DIATOMEiE.

465

distinguish, owing to their great variability in size and
proportion, on which account, too, their form is very
inconstant.

48. Climacospiienia. — Pacilli a latere primario
cuneati, vittis longitudinalibus moniliformibus, allero
latere obovato- la nceolal i, disseptis transversalibus in
loculos divisa.

The two species contained in tliis genns {C. australis,
C. moniligera), liave nothing in common except the
moniliform vittae. But in what these really consist we
cannot ascertain from the figures. In the first, Kützing
does not delincate the secondary surfaces, and from tlie
figure any one would say that he had drawn a Sgnedra.
The second, again, resembles a Podosphenia.

After this analysis of the family of Licmophorese
( Podosphenia , Phipidophora, Licmophora, Climacospiienia :),
we can only repeat what has been said of the first two
genera. And as, in our opinion, we ought to exclade
from it the genus Licmophora and nnit3 this to the
Surirellese, it will also be right to change the naine of
the family. Thus limited, it will remain allied to the
Gomphonemese more than to any other. As to the
so-called interanea, we liave already recorded their
arrangement in distinct globular masses as in Melosira.
Ehrenberg, treating of Podosphenia , says that this organic
condition is peculiar to young individuals ; and he says he
can distinguish, in the midst of the others, two of these
globules, which he regards as representing the male organs.
Ile asserts that, in some species, he has also seen the
gastric cells. But when they grow old, Ehrenberg liim-
self says that this internal substance accumulates in a
central inass, which is frequently radiated. Kützing, again,
describes the internal substance as disposed in two strips
{fettucce), applied to the primary surfaces, which divide
themselves transversely into two or more parts, and finally
resolve themselves into globules. But he certainly must
liave takcn these particulars from the genus Licmophora.

30

466

ANIMAL NATURE OE DIATOMEiE.

50. Striatella. — Bacilli tabulati longitudinaliter
vittati ; vittce pervice numerosce densce striceformes, stipes
lateralis.

Tliough the only species of tliis genus (ß. unipunctata ),
is common in the Adriatic, I confess myself unable to
form a clear idea of its structure. The complication it
presents in external appearance, and whicli is reproduced
in the figures of Kützing, seems to proceed frorn vittse of
the surface oppositeto the one observed shining through ;
there result from tliis, vittse, strongly and faintly marked,
alternating with each other. Does each one of these
vittse inclnde a canal? And how far do tliey project
into the cavity? The singulär condition described and
figured by Kützing of smaller tablets ( tavolette ) attached
to larger oncs, indicates a peculiarity of development,
whicli has 110 analogy in the remainder of the dass.

51. Tessella. — Bacilli late tabulati, non concatenati,
dense longitudinaliter vittati ; vittce medio interruptce
alternantes, stipes nidlus ?

This genus, too, is reduced to a single species (T.
interrupta ), and, therefore, it is impossible to judge of
the value of the characters tliat distinguish it from the
preceding or the succeeding, whilst we do not know the
organic importance or the true structure of the vittse.
The breadth of the tablets is remarkable, beingfive times
rnore than the length. There is frequently an absence
of a few vittse, accompanied at the same time by a
deformity or derangement of those contiguous. It
appears tliat this condition precedes the deduplication,
but we liave no observation in point. It still remains, also,
to determine the figure of the lateral surfaces.

52. Hyalosira. — Bacilli tabulati quadrati, concate-
nati lateraliter stipitati, interru.pte vittati ; vittce alter-
nantes medio lineolis subtilissimis conjunctce.

At first I was afraid tliat I was led, by want of skill in
observing, to believe tliat I could see in the two longer

ANIMAL NATURE OF DIATOMEAL 467

(; rectangida , obtusangula) of ttie four species of this genus
a continuation of the vittse from one margin to the other,
instead of tlieir being interrupted and alternating, as they
are figured and described by Kützing. Continuing my
observations, I succeeded at last in finding one individual
exhibiting to my sight the alternations described. Hence
I became convinced that the latter condition is not merely
inconstant but even the least frequent. The secondary
surfaces, neither described nor figured by Kützing, are
elliptico-acute, and on these are inscribed the smaller
concentric ellipses, which mark the margin of the in-
complete diaphragm formed by the nearest vittee.

53. Rhabdonema. — Bacilli tabulati concatenati late-
raliter stipitati, interrupte vittati et transversaliier
striati; vitta capitata. Stria transversa sinis longitudi-
nales numerosas formantes.

I have only had an opportunity of observing one ( R .
adriaticum ) of the three species of this genus ; and it is
because I must therefore limit myself to this that I can-
not agree to vvhat Kützing represents in his description
and figure. He omits to indicate the form of the tablets,
which can only be obtained by observation of the
.secondary surfaces, or by a longitudinal section ; and it
is entirely from this form that the appearances are derived,
on which the specific distinctions are supported. In the
Adriatic species, the figure of the secondary surfaces is
linear in the centre, and cuneato-attenuated ( assottigliata )
at the extremities. The frustules {bacilli), therefore, are
thick in the middle, have laterally the two primary
surfaces strongly inclined together towards the outside,
and are much attenuated in the extreme margin. The
vittaj are nothing more than canals projecting into the in-
ternal cavity, and projecting slightly, indeed, at the sur-
face, in the middle, and continuous from one extremity to
the other. In specimcns dried and softened again,
the canals themselves include air collected irregularly
into bubbles more or less extended. Hence the appear-

468

ANIMAL NATURE Or DIATOME/E.

ance of interrupted and capitate vittse. The appearance
of four transverse series is produced by the form of the
frustules ( bacilli ). The transverse strise are continuous
even across the vittse and canals; and it is only by atten-
tion to the slight projection of these, that, in withdrawing
the object by slow degrees from tlie microscope to bring
different parts into focus, we can see first the strise of the
intermediate spaces and not those of the canals, then the
latter and not the former, and vice versa if the object be
brought near again. They then appear always in inter-
rupted longitudinal series, but sometimes in the inter-
mediate spaces, and sometimes on tlie vittse ; and we can
never see tliem on both at once. Near the margins, the
differcnce of surface diminislies, and therefore tlie strise
appear continuous.

In tlie figure wliicli Ehrenberg gives of B. arcnatum,
(pl. xx, fig. 8,) the secondary surface is represented
simply elliptico-acute, and the vittse appear entirely con-
fined to the cxtremity. I suspcct this figure to be taken
from the extcrnal aspect rather than from direct Observa-
tion ; and from analogy witli our species, I should be
induced to believe that the primary surfaces remain
parallel to eacli other quite to the attenuation of the
extremities, and, therefore, that the series of the apparent
vittse becomes double rather than quadruple.

The four genera, ( Striatella , Tcssellci, llyalosira ,
RZiabdomena,) which constitute the family of Striatellese,
are certainly connected by a great affinity. Still it is dif-
ficultto determine tlieir mutual relations, orthe connexion
of the entire family witli others. Kützing places the
Striatellese in comparison witli the genera FrayUlaria,
Diaioma, and Achnanthes , as they do not specially differ
from the two former except in the abundance of vittse, to
which, I believe, the two usual longitudinal canals are
correspondent. Erom Achnanthes they differ as well in
form as in the absence of a central aperture. We will
compare tliem witli the next family when we have treated
of it, contenting ourselves at present witli intimating that

ANIMAL NATURE OF DIATOME7E.

4G9

they are more closely allied to the Fragillariese than to
any other preceding family.

Kützing rightly observes, that the Striatellese are
foimd indifferently, sometimes free, sometimes affixed. It
seems, however, that they were all originally in the
second of these conditions. Still, in the association of
individnals resulting from deduplication the Striatellese
repeat all the forms ofthe Fragillariese. Finally, as to the
interanea , Kützing says they are at first disposed uni-
formly, then collected into small spherules, which become
Condensed into a central globe. This last condition is
characteristic of the single species of the genus Stricitella.
But with regard to Hyalosira and Rhabdomena, I think it
important to mention the wasting away of the coloured
internal substance into longitudinal strips parallel and
intermediate to the vittse.

54. Tetracyclus. — Bacitti late tabulatia infilum arcte
connati, longiüidinaliter continuo et arcte vittati; a latere
secundario utroque apice late rotundati , ventro medio
maxime inflato , stipes nullus.

The presence of vittse solely distinguishes the single
species {1\ lacustris) from Odontidium. The lateral sur-
faces are convex, and traversed by transverse and arcuate
costse. I have not seen the straight median costa figured
by Hassall, nor the absence of these costse in the space in
the centre, as figured by Kützing. But because the
median lobe is strongly convex, its plane is different from
that of the lateral lobes ; hence, when the costse of one
can be seen, those of the other cannot, and vice versa. I
can in no way comprehend Kützing’s reason for enume-
rating this genus among the iJiatomece stomatiue, except
by supposing that he regarded as a large central aperture
the entire median cavity, which seems to bc open when,
observing the lateral surface too nearly, the corresponding
convexity escapes from the field of view. Fragments of
organisms, similar to Tetracyclus , are very common in the
fossil flour of Santa Fiore.

470

ANIMAL NATURE OF DI ATOMEN.

55. Tabellaria. — JBacilli adnati obsolete stipitati ,
demum semivoluti, concatenati, interrupte longitudinaliter
vittati ; a latere secundario ventre et apicibus inflati.

The Variation of form in the frustnies ( bacilli ) of tlhs
genus is very remarkable. On tliis acconnt it becomes
so very difficult to distinguish between the two principal
species (T. ßocculosa, T. fenestrata) of this genns, com-
mon in fresh water throughout Europe ; and the Synonyms
bccome so complicatcd and obscure.

Hence Kiitzing rightly sought the limits between the
two species in the fine character of alternate vittae in
T. ßocculosa, and opposite vittse in T. fenestrata. With
regard to thcse vittae, I observe that they are alike arranged
in fine strise, whicli continue without interruption even
where the vittse are alternate. Their alternation in T. ßoc-
culosa is not at all constant, and Hassall, too, makes this
remark.

After a long and attentive observation, I believe I have
convinced myself that the strncture of the Tabellariece is
something different from that described and figured by
our author. The primary surfaces have a rectangular
figure ; the secondary are linear, or rounded merely at
the extremities (as i find in authentic specimens of T.
fenestrata, from Jürgens), or swollen circularly in the
middle, or at the ends, as seems constant in T. ßocculosa.
It follows that the form is that of a cylindroid, strongly
compressed, or of tliree smaller cylinders, the central
one larger than the others, united together by parallel
walls, and placed at a distance less than the diameter
even of the lateral cylinders ; I never obtained a
sight of any aperture. The internal cavity is variously
divided by incomplete diäphragms. When one only
exists, as is frequent in T. fenestrata , it is clearly seen to
be furnished with a large central Perforation, and to con-
tain a canal, which, running along the internal wall of
the primary surfaces to where the cliaphragm detaches
itself, comes to communicate with another similar canal,
hollowed in the free margin of the diaphragm itself. When

ANIMAL NATURE OE DIATOMEiE.

471

we observe such a frustule ( bacillus ) on one of its
secondary surfaces, the large central aperture eludes the
eye ; still it may be seen, but only across the transparent
surface itself.

In this species we may frequently see two similar
diaphragms. In the T. ßocculosa, as many as nine may
be met with (Hassall). They are not all equally easy to
be seen in specimens that have been driecl and softened.
A green substance seems to be coagulated within them ;
and where tliis is wanting, the transparency prevents our
distinctly seeing either the canals or the diaphragms.

It is a frequent condition of the T. ßocculosa that this
coloured substance is founcl in one lateral half, and not
in the other, of the same canal ; hence the alternating
character of the so-callecl vittse. So there does not exist
a canal continuous to open extremities, which traverses
the frustules ( bacilli ), as autliors describe and delineate,
but many apertures (_ fenestrce ), arrangecl in a series, in
which bubbles of air remain imprisoned, unable to make
their escape without rupture of the shield.

In the T.fenestr ata, every individual has two diaphragms
when the development is complete. When deduplication
takes place, two individuals are producecl, each having
one diaphragm.

The second diaphragm afterwarcls appears, and, at a
later period, another deduplication. It is still a ques-
tion whether both the new individuals equally divide;
whether a new diaphragm appears in botli or in one
only ; whether on the inner or outer side ; and whether
among the four individuals resulting from the second
deduplication, those are equally prolific which retain
the primitive diaphragms, or those which have new ones
only, — or both together ? In the T. ßocculosa it is rare
to see one diaphragm only ; and, again, it often happens
that two contiguous frustules ( bacilli ) possess different
numbers of them. Therefore, besides the inquiries indi-
cated above, another might be instituted on this species,
— whether or not tlic deduplication is always subsequent

472 ANIMAL NATURE OF DIAT0ME2E.

to the formation of a diaphragm? a circumstance in
which tlie essential difference between tliis and the pre-
ceding species seems to reside.

In the fossil flour of Santa Eiore, besides the T.
amphicephala , we find many fragments which cannot all
be referred to the two preceding species. The vittse
seem to liave disappeared in all, owing to the absence of
colouring matter, and the under-mentioned conditions of
the shield are clearly seen in all.

It is justlyobserved, byHassall, thatthereis a difference,
in the mode of connection, between the two common
species (flocculosa, fcnestrata). In the second, tliere is a
distinct cushion (cussinetto), in the form of a hinge,
connecting one frustule to another. In the first, the
angles are nearer together, the hinge is wanting, and
tliere remains in its stead a sort of detached border,
showing that the very fine external inembrane has becn
laceratcd, yiclding to the excessive distcnsion, but
persisting partially to maintain the union, and without
retracting itself, as it must do, in the other species, to
originate the hinge.

Tliis divcrsity of condition appears to me in accordance
with the different period of development at which the
deduplication occurs in the two species, as well as with
the other considerations already mentioned. I think
that we ought to take tliis fact into account, as also
serving to support my opinion, as to the nature of this
external membrane.

Besides the two living species, and the fossil one just
mentioned, Kiitzing describes another, discovered by
Lenonnand; and enumerates three from America, the
discovery of which is due to Ehrenberg.

56. Terpsinoe. — Bacilli tabulati adnati , obsolete
stipitati, demum semisoluti et isthmo co?icatenati, viltis
transversalibus abbreviatis marginalibus ( non perviis )
capitatis in latere secundano nodosi.

If we imagine a series of frustules of Tabellaria joined

ANIMAL NATURE OE DI ATOMEN. 473

together, not laterally, but the head of onc to that of
another ; or, in the direction of breadth instead of length,
we shall form the most just idea of the only species of
this genus, (T. musica ). And though I could not study

it in the very small fragment with which Kützing favoured
me, I still think I can assert that here also, as well as
in the preceding genus, thecanals run without interrup-
tion along the attachment and the free margin of the
diaphragms ; and the apparently capitate vittse are
produced either by animal matter, or an open space in
those imprisoned canals.

Fragments, similar in appearance to what is seen
laterally in the m argin s of the frustules of Terpsinöe, are
met with in the fossil flour of Santa Fiore.

57. Grammatophora. — ßacilli oblongato tobulati ,
adnati dernum semisoluti et isthmo concatenati ; vittae
longitudinales semper bince, medio interruptce,plus mitiusvce
curvatre.

Kützing, treating of G. marina , the most common,
remarks that by calcination the exterior inflexions of the
vittae disappear, and that, on this account, a greater
distinctness is acquired by the canals, in which these
vittae are situated, and which extend uninterruptedly the
entire length of the frustules. Iie represents these
canals, by two delicate lines, one external, the other
internal, to each vitta, as well in this species as in
all the otliers. I see the external line clearly, and
to me it seems to indicate the conjunction of the secon-
dary valves with the primary. The striated margins,
seen in many species ( tropica , gibba , gibberula, serpen-
tina) belong to the lateral surfaces ; and when, as in
G. marina, they are smooth, they turn yellow by the
action of lieat, like the remainder of these secondary
surfaces. On account of this colouring, it is difficult
to see the external arches of the vittae, for these lines
run at a tangent to them. 1 suspect that along this
suture thcre runs a fine canal, hollowed out in the

474

ANIMAL NATURE OE DIATOME^E.

thickness of the wall, the cavity of which appears as
a furrow, or ratber as a Perforation, at the extreraities.
The oval aperture (fenestra), wliich is visible in the
middle of the secondary surfaces, belongs to tliem in
appearance only, as in the preceding genera. It is only
seen because of the transparency. In Grammatophora ,
also, the appearance of interrupted vittae, is produced by
the presence of diaphragms pierced by an ample central
elliptical Perforation, and containing a distinct canal along
their attachment to the wall. Ehrenberg, too, describes
these diaphragms, wliich divide the internal cavity
regularly into three distinct compartments. This ar-
rangement is also shewn by heat, and by acids ; and the
various portions separate themselves so neatly, that we
may, in a certain manner, effect amost accurate dissection.
In this gen us, these diaphragms have the characteristic
condition of very various degrees of flexature, which are
constant in eacli species, and impart to tliem the most
elegant appearances. ln the deduplication, the line of
division between the new individuals, and the fine lines
which form the boundaries of the two new lateral surfaces,
precede the appearance of the corresponding diaphragms.
These are the fine lines delineated by Kiitzing within the
vittae, and regarded by him as the internal margins of
the canals, in which he believes the vittae themselves to
meet together. The deduplication of Grammatophora
greatly resembles that of Achnant Indium.

Ehrenberg describes the internal substance as consisting
of a central transparent and colourless body, containing
small gastric vesicles, and terminated at each extremity
by three-lobed dark-green appendages, which project into
the three corresponding cavities. The cushions (cuscinetti)
or hinges that retain the frustules in connection are
very evident, in all the thirteen species of this genus, as
in the Tabellaria fenestrata ; and this remark goes to
confinn what we have said of that species.

The family of Tabellarieae ( Tetracyclus , Tabellaria,
Terpsinöe, and Grammatophora) constitutc by themselves

ANIMAL NATURE OF DI ATOMEiE.

475

alone the order Stomaticaß. The tvvo preceding families
(Licmoßhorece and Strialcllece) are comprised in the order
Astomaticae. These two Orders constitute the tribe of
Diatomeae vittatae.

Any one examining these beings with diligence will
entirely convince hiraself that the distinction of the two
Orders is altogether insufficient. No Tabellaria has a
central Perforation in the secondary surface, at all to be
compared with that of the Diatomeae, constituting the
order Stomaticae in the preceding tribe. Nor have I
succeeded, moreover, in discerning the other four
perforations, described by Ehrenberg as existing in the
middle of the terminal surfaces. As to the four genera
comprised in this family, since the sole character by
which they were United together, and which was brought
to establish the principal distinction between the Fra-
gillarieae and Striatelleae, has been proved to be erroneous,
it will remain to be inquired whet.her there be other dis-
tinctive characters. I firmly believe that Tabellarieae
and Striatelleae ought to constitute one family, since the
diaphragms, which Ehrenberg considers characteristic
of the second exclusively, are not wantfng in the first.
The only doubt that I could rationally entertain would
arise in respect to the genus Terpsinöe. The figure
of the lateral surfaces, the total form of the frustules,
the arrangement of the vittae, the direction of the appa-
rent transverse canal, finally, the similarity to the other
allied genera in external aspect, would induce us to regard
the frustules as connected to the heacl of each other,
rather tlian laterally ; as we have already stated, to give
a clearer idea of the subject. But then, how can we recon-
cile the transverse deduplication with all the other instances
in which, on the contrary, it is longitudinal? Eor if we
would attribute a greater degree of generality to this law
than to any other ; setting out from the direction of the
deduplication, always parallel tothe secondary surfaces, to
decide upon the correspondence of all the other parts
with each other, we must then withdraw the title of

476

ANIMAL NATURE OE DIATOMEiE.

general from the otlier law (which is laicl down as general),
that the direction of the vittae is alwäys longitudinal. In
either case, the genus Terpsinöe varies entirely from its
allies, so that I think it must be regarded as the type of
a distiuct family.

Owing to the mere presence of vittse, Kützing has
elevated the group of three families just examined, no less
than to a degree superior to that of an Order, and which
he denominates a tribe. The analysis we have instituted
appears to me sufficient to prove that this characteristic
condition is solely due to the larger development of an
organ which really exists, or is in some degree repre-
sented, in the various families of the preceding tribe.
And though, systematically, wc might vvisli to assign it a
great importance, yct in a natural Classification it must
certainly be subordinate to the assemblage of characters.
Thcreforc, abstracting tliis character, and looking solely
to natural affinitics, I bclieve that the Licmophoreae ought
to be placed near the Gomphonemem, with the exception
that the genus Licmophora is to be placed by the side of
Synedra, and therefore in the family of Surirellese ; and
all the other vittated Piatomese must be ranged in the
order Tragillariese.

58. Coscinodiscus. — Individua solitaria, libera , lorica
bivalvis silicea, in latere secundario disciformis, cribrata.

The only essential character that distinguishes this
genus from the Cyclotellce, is the areolation of the
secondary surfaces. And it is entirely on this account,
that, wliilst belonging to the first tribe, it is placed in the
last. We ought to repeat here, that when treating of
Cyclotella, we noticed the points and radiated lines in
the lateral surfaces of the freshwater species ( operculata ,
Meneyhiniana ) and the fossil ones, (i minutula , Ilolula,) a
circumstance that imperiously requires an Union of the
two genera. In what relates to this areolation, the expres-
sion cribrata, of Kützing, includes a false idea, inasmuch
as these cells are not perforations at all, as this author

ANIMAL NATURE OF DIATOMEyE. 477

states (Jorica perforatd). The observation that, by pkcing
the object altern ately nearer to, or more clistant from, the
microscope, the cells and their intermecliate spaces appear
successively in light and shade, is sufficient to prove that
the appearance is produced either by simple depression or
elevation, causing a difierence in the surface, or perhaps
by minute cavities in the thickness of the wall itself.

Kützing takes no notice of the marginal perforations
described by Ehrenberg, who enumerates as many as
twenty-five in C. lineatus.

Ehrenberg describes the internal substance, either
collected into a globular mass in the centre, or radiating
irregularly all round from the centre towards the circum-
ference, or more frequently arranged in small distinct
globules, like those of Melosira. He sees, also (C. patina),
a globular gland, and a contractile diaphanous areawhich
he believes to belong to the male sex.

59. Actinocyclus. — Individuci solitär ia, libera ; lorica
bivalvis silicea, disciformis ( breviter cylindricci) cellulosa ;
cell ul ce radiis pluribus leevibus interruptce. /Sepia interna
nulla.

In a specimen of chalk marl, from Oran, in my pos-
session, which consists almost entirely of Coscinodisci,
Dictyoclice, Melosira , and spiculse of sponges, I could
not possibly find a single Actinocyclus, although seven
out of twenty-four species of this genus are indicated in
this substance. This proves only one circumstance,
which, for other reasons, can easily be imagined, that in
the same formations the species and genera appear to be
different at different points. I think, also, that I ought
to introduce two observations equally applicable to this
genus and both the preceding and subsequent genera.

Among the innumerable valves of most species of
Coscinodiscus, more or less regularly curved, many are
found to be flexuose or curved in various ways ; there is
this variety of curvature in valves perfectly similar to
each other in every other character. Considering, tlien,

478

ANIMAL NATURE OF DIATOMEjE.

that in A. undulcitus the six apparent rays are produced
by a similar flexuosity, a doubt necessarily arises, either
that the two genera are not sufficiently distinct, or that the
characters deduced from tliis flexuosity are not sufficient
to distinguish the species. There occurs, also, naturally
to the mindj a comparison under tliis aspect of the
Coscinodisci with Campylodisci and the flexuose Surirella.

In sorne individuals exactly referable to Coscinodiscus
eccentricus, and which preserves both the valves, there
are seen five incomplete radii, which vanish entirely when
the object is withdrawn so far from the microscope that
the surface only is visible. I conclude from tliis that
tliese radii are so many internal partitions ( setti ). On
tliis supposition, the species would not belong to any one
of the tliree genera. Besides Ehrenberg having also
found it alive near Cuxhaven, in the North Sea, it would
sccm improbable that such an organic condition could
have cscaped so expert an observer ; and we must, there-
fore, suppose that a different tliing is referred to.

Kützing describes and represents the radii to be per-
fectly smooth ; Ehrenberg, again, thougli he does not
express it in his figures, says that they are finely punctated.
In almost all the species there are indicated marginal
apertures corresponding to the radii. In many, which
Ehrenberg observed alive, the coloured internal substance
was variously grouped into many lobes near the centre.

GO. Actinoptyciius. — Individua solitaria libera, lorica
bivalvis silicea disciformis ( breviter cylindrica), cellulosa ;
cellulce radiis septiseyue internis radiantibus pluribus
interruptee.

The beautiful observations of Ehrenberg are fruitful in
very important particulars relative to some species of tliis
genus, ( duodenarius , sedenarius, octodenarius.) Of these
particulars, Kützing takes no notice. The triangles into
which the disc is divided by the radii, appear alternätely
clear and dark, precisely as happens in Actinocyclus
vndulatm , where that appearance is evidently produced

ANIMAL NATURE OF DIATOMEiE.

479

by the flexuose state of tlie surface. A line traverses
the middle of these triangulär spaces. The mar-
ginal perforations correspond to the lines wliich border
the triangulär spaces in A. sedenarius, to which again
they run in the middle of those of A. duodenarius
and of A. octode?iarius ; and the internal septa {setti),
according to Ehrenberg, always correspond to those radii
which do not terminate in an aperture. We learn, too,
from the figures, that the areolation of the surface is con-
tinued without interruption even over the radii, and that,
besides the indicated apertures, there are visible also
those of the opposite surface, which alternate with the
former. And Ehrenberg observes, that on this account
there occurs an optical illusion not easy to explain.
Hence arises a suspicion that an equal number of septa
{setti), but alternating with each otlier, project from the
inner superficies of both surfaces without reaching the
opposite surface, and so the marginal apertures belong
sometimes to one, sometimes to the other.

All the species do not seem to have the same structure.
In some, at least, ( ternarius , senarius, octodencirius,) the
radii are figured smooth, as in Actinocyclus ; it is not
said that the triangulär spaces are alternately clear and
obscure, nor that they are traversed by a longitudinal
line ; and there remain doubts as to the marginal
apertures.

As to the internal Organisation, little can be collected
from the observations of Ehrenberg.

Finally, it deserves attention, that the fourteen species
enumerated in this genus differ almost exclusively in
the number of radii. Two only, {senarius, hexapterus,)
having the same number, are much different from each
other. Three have unequal numbers.

The family of Coscinodiscese {Coscinodiscus, Actinocy-
clus, Actinoptychus ) is, even in the opinion of Kützing,
more nearly allied to that of the Melosireae than to any
other. I believe that both the Campylodisci and flexuose
Surir eilen are to be regarded as allied to this family.

480

ANIMAL NATURE OF DIATOMEiE.

61. Lithodesmium. — Individua a latere secundario
triangula in corpus prismaticum articidatum conjuncta.

The several frustules are united toget.her by a shorter
intermediate body, in which Ehrenberg observed a granu-
lated surface ; Ibis, he says, appears in yonng individuals
only, which are, therefore, pliable when dried. Ile
regards this granulation as indicating the process of
siliceous ossification.

The only species of this genus [L. undulatium ) in-
habitin g the North Seas, is too little known to exclude
all doubt as to its nature.

62. Amphitetras. — Individua a latere secundario
quadrangula (depressa) ad angula isllimo mol/i concatenata.
Catence breviter stipitatce adnatce.

Kiitzing himself obscrves, that the species of this
genus may easily bc thought to belong to the Isthmice.
The only difference is that upon which the distinction of
the cntire family is founded, that is, the angular figure of
the lateral surfaces. This charactcr is, indeed, extremely
conspicuous, and in want of other data may serve very
well to distinguish genera. But that this is of itself
sufficient to separate, not families rncrely, but even
Orders, will be conceded witli difficulty in a natural
Classification.

I found the very beautiful A. aniediluviana among
some spccimens of Biddulplria quinquclocidaris, from
Calvados, obligingly supplied by Brebisson. The smooth
fascia deserves attention ; it traverses the frustule in the
direction of its length. It is sometimes absent, some-
times double, or even triple. The appearance of the
areolation is different from that of the allied genera.
It seems produced by minute projecting papillse. The
ample round apertures are very evident, corresponding
witli eacli of the four angles of the secondary surfaces, as
described by Ehrenberg, but omitted by Kützing from
bis description as well as bis figure.

ANIMAL NATURE OF DIATOMEiE.

481

Kützing docs not acquaint us with his authority for
refemng as a doubtful synonym of this species to the
Isthmia vesiculosa of Agardh, which, from that author’s
description, would rather appear to be a Desmidiea. In
my monograph of the Desmidieae (1840), I had regarded
this species as the type of a genus, which at that time
was by Kützing denominated Isthmosira.

I liave not happened to meet with the A. adriatica
recently published by Kützing, ( Pliycologia Germanica ,
p. 115,) which, by the strong prominence of its angles,
is rnuch more allied to the Isthmice.

It is to be observed, that this projection varies very
much in the preceding species, as stated by Ehrenberg,
and as I have observed in the specimens before men-
tioned. The other species, A. parallela, which hitherto
has only been found in a fossil state, seems to be very
distinct.

63. Amphipentas. — Individua pentagona.

Both species of this genus are of a doubtful nature.
Collecting liere together all that is referable to the family
of Anguliferse, (. Lithodesmium , Amphitetras, Amphipentas,)
I can only repeat what was before said of the second of
these genera. The first is uncertain in its natnre, but,
at all events, can have no affinity with the second. The
last has some resemblance, at least in external ap-
pearance.

The two families, Coscidonisceae and Anguliferse, con-
stitute the order Disciformes. I know not what character
can have led Kützing into this Union, for the very name of
the second family contradicts that of the order. I believe
that the Coscinodisceae cannot be separated from the
Melosireae, and that the Anguliferae, excluding the
genus Lithodesmium, ought to be unitcd to the Bid-
dulphieae.

04. Tripodiscus. — Individua singularia ? libera ?

31

482

ANIMAL NATURE OE DIATOMEiE.

lorica bivalvis cliscoidea circularis, in utroque latere
( secundariö ) tribus processibus appendiculata.

The only species of this genus, which of itself consti-
tutes the farnily of Tripodisceae, does not essentially differ
from the Coscinodisci, except by three short appendices
projecting from each of the lateral surfaces, which are
tubulär, and terminale in an aperture. Ehrenberg,
also, suspects the presence of otlier sraaller marginal
apertures. The areolation of the sur'face is so confusedly
represented in the figure, as to lead to the belief that
even the organic condition is complicated, which gives
that appearance.

G5. Isthmia. — Individua trapezoidea vel rhomboidea,
compressa, cellulosa, zona transversali ex cellulis minoribus
formata , notata , stipitata , isthmis majoribus in catenas
subramosas irreguläres conjuncta. Divisio oblique trans-
versa.

The complicated synonymy of the two species of this
genus ( enervis , nervosa) justifics the new name given by
Kützing to the sccond. The Conferva obliquata of Smith
bclongs to the first, and therefore Ehrenberg was in
error when he bestowed upon it a new specific name
{enervis). The other required to be named, and Kützing
was fully entitlcd to call it L. nervosa. By the laws of
synonymy, therefore, the two names obliquata and
nervosa ought to remain. The longitudinal costae of this
latter are quitc extraneous to the surface ; they project
slightly into the interior cavity. Both in the one and
the other the siliceous cellular membrane of the median
portion persists, whilst within it a formation of two
lateral valves takes place, which complete the two indi-
viduals prececling from the deduplication. This process
reminds us of that of the Achnantheae, and approaches
the reduplication of Desmidieae.

The transverse zone, represented by Kützing in the me-
dian portion, is neither constant nor regulär. I believe it
to be produced by the permanence of some portion of the

ANIMAL NATURE OF DIATOME2E.

483

cellular siliceous external membrane, which is lacerated in
the deduplication. A portion of it may remain in the
middle, whilst its lateral extremities are denuded, or vice
versa, the former may remain denuded, and the latter
covered. It still remains to be explained how the
formation of the new valves takes place, whether they are
organised in situ , or project by degrees from the companion
valves, to which they are contiguous from the beginning,
the intermediate ring only developing itself subse-
qnently ( consequentemente ), as in Melosira.

The gelatinous isthmus, which connects the individuals
together, and the stipes by which the entire chain
is affixed, seem to prove the presence of an exterior
gelatinous membrane.

66. Odontella. — Individua leevia, compresso tere-
tiuscula medio fasciata utroque cipice cornibus binis late-
ralibus instructa et concatenata, adnata.

I am compelled, by the want of specimens, to confine
my examination to that one only of the five species of
this genus which I have alreacly treated upon in refer-
ence to my Pleurosira thermalis ; and I can only insist
upon what I have stated on that occasion. The indi-
viduals of Odontella polymorpha, have an elliptic cavity
in the middle, and at the extremities are compressed in
the direction of the greater diameter of that ellipse ; but
viewed laterally, they present an obtuse, but linear edge
(i canto ). The lateral processes, by which the individuals
are connected together, are very evident. The clifference,
therefore, between this form and that of Pleurosira
thermalis, and of P. Baileyi, is very great. Another
important difference exists in the conjunction of the
median ring with the two lateral valves. In my Pleu-
rosira there is on both sides a large, distinct, circular
canal ( canaletto ), evidently projecting into the inner
cavity, and corresponding to an external furrow. But in
the Odontellcß there exists neither furrow nor projection ;
and I really doubt whether there be a fine canal. A

484

ANIMAL NATURE OE D1ATOMEJ5.

like condition exists in botli with respect to the delicate
points on the sliield, which Kützing says lie has omitted
in Ins figure of Odontellci ; tliese being absolutely re-
ferable to the internal substance, as in the Melosiroe.

67. Biddulphia. — Individua concatenata, pundato-
cellulosa ( cellulis in lineas redas transversales ordinatis),
utroque latere obtusc dentata ( dentibus marginalibus majo-
ribus) septis transversalibus internis locidosa.

The inner cavity is not divided into distinct transverse
cells, because the septa, far from being complete, only
project in a very little way. Their greatest prominence
corresponds with the extremities of the frustule, and
tlicnce thcy proceed, growing more slender, towards the
margins of the lateral valves, to which they exclusively
belong. A similar elevated rim (orlo) in the internal
cavity liraits, also, the lateral processes by which the
frustules are connected together. Eacli of tliese processes
terminates in an acute corner {spigolo), and has there-
fore a three-sided figure, and is situated obliquely.

The terminal surfaces (lateral in respect to the chain)
are smooth, or they present an elliptico-elongate figure,
traversed, parallel to the smaller axis, by two lines which
mark the conjunction of the two lateral valves with the
median body. Corresponding extern ally to tliese lines,
is a deep furrow, which is clearly seen in the projecting
corners (spigoli) ; internally there is a projecting fold
( cercine ), like an incomplete diaphragm of the areolar
border. Hence the form of the frustules is very different
from that indicated by Kützing, who represents them as
flattcned cylindroids. Bor they are almost parallelo-
pipeds, and wlien they are United together by an external
siliceous cellular membrane, more or less incompletely
persistent, they constitute a prismatico-quadrangular
filament. Wlien they are free, the extremities are
thinned, rounded, and lobed, according to the number of
incomplete cells. The two primary surfaces are smooth ;
they present transverse elevations and depressions in

ANIMAL NATÜllE OF DIATOME/E.

485

corresporiclence with tlie cells above mentioned. The
lateral processes are more or less coinpletely denuded of
tlie fine cellular membrane, and are united in con-
catenation with each other by a cushion (cuscinetto) ,
bounded externally by a precise line, but internally
irregulär.

The deduplication takes place in tliis genus as in tliose
preceding. The double ligament merits observation,
which remains to unite the median lobe of both surfaces
of each extremity with the corresponding (ligament) of the
adjoining frustule. This ligament, from the gradual elon-
gation,breaks across in the middle, maintaining its rigidity.

In the Adriatic we have the two species, quinquelocu-
laris and trilocularis. To the second I refer a form with
smaller and less elongated frustules, which at first I
thought a new species, and as such communicatecl it to
Kützing, who, on the other hand, believecl that it belonged
to the quinquelocularis. I note this circumstance to in-
dicate an important organic condition. When the frus-
tules are empty and diaphanous, we can easily see,
owing to the transparency, the costse of the surface
opposite to the one observecl, and especially the two
extreme ones, which correspond to the least thickness,
and can therefore be seen along with those of the anterior
surface. The number of the so-called cells is then appa-
rently increased by two. It happens in this way that
the quinquelocularis sometimes resembles the septem-
locularis.

Kützing ascribes to this genus, as a doubtful species,
the Denticella Fragillaria, of Ehrenberg.

In the quinquelocularis , I once saw a frustule broken
in the direction of the conjunction of the lateral valves
with a median cincture, and surrounded by 4 — G poly-
hedral corpuscules, of a diameter equal to one fourth
that of the frustule, and of a cellular structure, adhering
to the margin of the fracture.

Finally, we cannot but remember the Isthmia ner-
vosa, which seems to difler from Biddulphia in 110

486

ANIMAL NATURE OE DIATOMEiE.

otlier respect tlian tlie trapezoidal figure of its primary
surfaces.

68. Zygoceros. — Individua liier a (?) compressa
utrinque corniculis doubus perforatis instructa, non cou-
catenata.

The two species of tliis genus, [Z. Surirella, Z. Rhombus)
were observed in a living state by Ehrenberg, who saw
that they were always free, and thence established,
principally on the want of stipes and of cateniform con-
junction, their generic distinction from Biddulphia.

He observed, also, the sinooth median fascia which he
compared to that of the Melosirce. Having regard to the
rhomboidal figure of the section, and the large terminal
perforations of the two lateral processes, the compari-
son witli the genus Amphitetras is much closer.

In the chalk marl of Oran, I saw a fragment which I
could not better refer to any otlier genus of Diatomese.
It was an oblong body, witli three lobes on eacli side,
and two lobes witli a large circular Perforation at the
two extremities. The space corresponding to the two
median and more prominent lobes, was divided from the
two others by means of two very distinct lines, and the
whole surface was regularly areolated.

The family of Biddulphia) ( Isthmia , Odontella, Biddul-
phia, Zygoceros ,) has affinity, according to Kützing, witli
none but the following one (Angulatae) ; and in the letter
before rcferred to, he intimated to me his tliouglits of
reuniting them to the Tripodiscieae. Here I remind the
reader of what I have said on the genus Amphitetras, and
of the family of Anguliferse, which, perhaps, excluding the
genus Lithodesmium, seems strictly to connect itself witli
the Biddulphieae. If there really exist also an affinity
with the Tripodisceae, as Kützing maintains, that affinity
may suggest the transition to the Coscinodisceae and
thence to the Melosireae.

In respect to the internal Organisation of the Biddul-
phieae, we learn, from the fine observations of Ehrenberg,

ANIMAL NATURE OE DI ATOMEN.

487

that tliere is always a coloured substance disposed in
lobes, wliich he supposes to represent the ovaries, in the
midst of a transparent and colourless body.

69. Triceratium. — Individua libera, lorica bivalvis
triangula, in utroque latere tridentata vel. corniculata, non
concatenata.

The perfect resemblance of the primary surfaces, and
the large apertures of the three processes in the secondary,
render this genus precisely intermediate between Amphi-
tetras and Zggoceros ; nor, indeed, can I comprehend
how Kiitzing could place them in three separate families,
and even in two distinct Orders. As to the rainute
apertures, which Ehrenberg states to be uncertain. in the
conjunction of the lateral valves with the median fascia,
we may suppose that they are only apparent as in the
Biddidphive, where they certainly do not exist. Of the
four species hitherto described, two (Favu-s, striolatum )
were observed by Ehrenberg and by Sonder in a living
state, in the North Sea. '

Like Zggoceros, the Triceratia become detached com-
pletely in deduplication, and, therefore, do not, like
Ampldtetras, form cateniform chains. They possess, also, a
more decided motion. This character, however, does not
appear to me of so much importance as of itself to fix
the limits of distinct families; and Kiitzing himself,
who proposes a separate family (Angulatse) for the
genns Triceratium, comprises Zggoceros in that of
Biddulphiem, where the catenseform association is so
preponderant.

70. Actiniscus. — Individua solida radiata, stellam
cevndantia.

Although, besides a species exclusively fossil (A. Stella),
omitted by Kiitzing, one of the other two has beeil
observed alive by Ehrenberg (A. Fentasterias ), and the
other exclusively in this state, (A. Sirius,) still we

488

ANIMAL NATURE OF DIATOME/E.

have iio positive data as to tbe internal Organisation of
tlie genus.

71. Mesocena. — Individua libera solitaria , annulum
circularem aut angulosum scepte spinescentem referentia.

On tbe five species of this genus we can only repeat
wliat has been said of Actiniscus.

72. Dictyocha. — Individua reticulata spinosa, libera,
sulitaria.

Independently of tlie distinctive cliaracters of tbe ten
spccies (one, tlie I). gracilis, being added by Kützing)
which merit attention by tlie varicty of form, size, pro-
portion, disposition, and even numbcr (D. aculeata , B. tri-
fenestratd) of tlie (maglie) cavities, as well as tlie presence
and lengtli of tlie spines, already noticed by Ehrenberg,
tliis author’s observations on soine of tliese species that
may be studied in a living state (aculeata, Speculum , Fibula)
are very valuable. Erom tliese it appears that tlie animal
is soft, and quite external to tlie siliceous body which it
bears on tlie surface, like a dorsal sliield (scudo), as the
Arcellce bear their calcareous sliell.

Tliough observations are wanting to show that the
Organisation proved only in some species of this last
genus ( Dictyocha ), is common to the whole family of
Actinisccse, yet we may infer by analogy that it is so.
ln fact, we cannot interpret the structure of those beings
in any other way than by supposing the body of the
animal to be external.

And liow sligbt soever, may be our knowledge of the
Dictyocha, it is still more than sufficient to prove an
organic type not merely quite different from that of the
other familiescomprised in the same Order (Appen diculatse),
and in the same tribe (Areolatse), but even from the
type of all the other Diatomese.

I believe that whatever be the rank assigned to the
group of Diatomese in the Zoological series, the first

ANIMAL NATUllE OF DIATOMEiE.

489

division ought to Le tliat of true Diatomeae and Actinisceac.
Yet, in the actual state of Science, we may characterise
the first as completely loricated, the seconcl reduced, in
the dermal skeleton (dermoscheletio) , to the presence of
a simple dorsal shield. It is indeecl true, that, in other
classes of animals (Mollusca), the characters derived solely
from the dermal skeleton have not so high a taxonomic
value. It is possible that we may come to establish
the basis of Classification, even in Diatomese, upon the
particulars of their intimate organic structure ; but since
this may never be realised, I believe that, provisionally
at least, this character should be consiclered the prin-
cipal one.

The order, therefore, of Appen diculatae (Tripodiscieae
Biddulphieae, Angulatae, Actinisceae) is the most artifi-
cial of all, and even in that respect inconsistent. ßy the
same title that Zygoceros and Triceratium are inserted,
we ought also to insert Amphitetras and Ampi dp enteis
(if they be true Diatomeae). The Biddulphieae constitute
a very natural group, when we unite the Anguliferae
and exclude Lithodesmium and the Angulatae. There
would remain some doubt as to the genus Odontella ,
in respect to the want of areolation in the shield. Tri-
podiscus would remain int.ermediate between this group,
and the Coscinodisceae. Finally, the Actinisceae, in my
opinion, ought to be entirely excluded.

Thus the entire tribe of Areolata (Disciformes, Appen -
diculata,) would be reduced to three groups only,
(Coscinodisceae, Tripodisceae, Biddulphieae,) to which,
this denomination really belongs. And here, we cannot
but adduce some considerations on the organic condition
that gives origin to it. In the Biddulphieae, the struc-
ture of the shield seems evidently cellular. In the Cos-
cinodisceae we have supposed it to be such on' account of
the optical phenomena it presents, and examination
confirms this supposition. Comparing, tlien, the tribe of
Areolatae with the preceding, under this point of view,
and independently of the animal or vegetable naturc

490

ANIMAL NATURE OE DIATOMEiE.

of Diatomeae, consiclerecl as orgauised beings, we find
onrselves of necessity, reduced to a dilemma. Eitlier tlie
shield of the Areolatae has a structure entirely different
from that of the other Diatomeae, or the shield of the
latter has a compound structure, which escapes the eye,
though arraed with the highest magnifying powers,
owing to the tenuity, and minuteness of its elementary
parts. Perhaps some one may attempt to elude the
question, by ad mittin g that this shield can be no other
than a product of secretion. But, besides that, the
products of secretion are living beings, organised and
susceptible of their own ulterior organic modifications,
as we have previously demonstrated : in eitlier mode it is
necessary to admit a particular Organisation in the se-
creting organ, because its products assume a particular
configuration and texture. If, therefore, the vital and
organic power be understood as limited solely to the soft
substance, and extended aftcrwards to the solid, it always
comes to be the same thing — the peculiarity of Organisa-
tion. The difference is reduced to the soft or solid
Constitution ; nor does this isolated condition prove, in
my opinion, the mineral condition of a tissuc which does
not present any character eitlier of crystallization or
inorganic deposition.

Of the two discordant opinions, I believe we ought
to admit that which supposes by analogy the usual
elementary structure to prevail in the slhelds of all
Diatomem. And, in truth, the presence of striae, points,
depressions, elevations, manifests, in many even of those
not areolated, a structure neither uniform nor continuous.
We find, too, that independently of this condition, many
degrees of corrclation connect the genera of the last tribe
to some of those of the two preceding. The Odontella
are rightly placed near the Biddidpliia and Islhnia,
though they do not possess an areolated shield. And if
a decided organic affinity be undeniable in the entire
Organisation of such beings, it is reasonable to suppose,
that even in tlie structure of an organ common to them

ANIMAL NATURE OF DIATOMEiE. 491

all, tlie differences may be produced only by a slight
modification in form, and principally in tke dimensions,
of tlie organic elements.

It remains to be decided wliat tliis structure is. The
shield of the Biddulphiese seems to be a very simple
cellular tissue. It is true, sufficient observations on its
origin, formation, and successive growtli, are wanting ;
bnt although we liave no direct observations (whicli
may deceive), we ought necessarily to admit it to
be such. It will then be the same as that of other
Diatomem, which often appears to be a very simple,
uniform, and continuous vitreous lamina, but this appear-
ance, perhaps, arises from the minuteness of the cells of
which it is constituted, or from their complete obstruction
and perfect continuity.

Whatever be the structure of the Areolatse, it can
never be regarded as belonging to the walls of a cell.
Indeed, on the supposition of the vegetable nature, and of
the inferior rank that the Diatomeae would occupy in
the dass Algae, we must assert for tliese, as for all the
others, the same condition of a simple cell. For in a
System where the distinction of monogonimic, poly-
gonimic, and coelogonimic cells is adduced as of high
taxonomic value, a character of so much higher import-
ance cannot be lightly neglected.

The study of microscopic beings presents much greater
difficulties than that of the microscopic parts of larger
organisms. The ideas that we habitually form to our-
selves of the great and the small, are relative to the
capacity of our senses, and he who sharpens thöse senses
the most by the aid of physical instruments, most extends
the relations of those ideas, to distant confines. In this
way we come to persuade ourselves, that in nature there
exists no absolutely great nor absolutely small. The
minutest organisms are not, therefore, the most sim-
ple in construction, and their Organisation frequently
baffles all means of observation. It follows, from these
reflections, that in the study of beings of a given family

492 ANIMAL NATURE OF DI ATOMEN.

or dass, it assists us greatly if we select those tliat
present tlie greatest complication of structure, because
the comparison of these may reveal the Organisation
which otliers disguise under an assuraed simplicity.

In the three tribes we have examined (Striatae, Vittatae,
Areolatae), Kiitzing arranges all the Diatomeae which he
believes to form a section of the first of the two classes
into which he divides all the Algae. No one who con-
siders that even the Charae are comprised in the same
dass, will feel any wonder at this assemblage. But
without calculating either the degree or the position
attributed to the group of Diatomeae in the Organic
Kingdom, and attending only to the examination of their
ulterior division, 1 believe that the observations adduced
may serve to demonstrate that in the three proposed
tribes we have unnatural dismemberments and asso-
ciations. The same conclusion prevails also in respect
to the six Orders (Striatae, astomaticae and stomaticac;
Yittatae, astomaticae and stomaticae ; Areolatae, discifornxes
and appendiculatae,) as well as to the ulterior divisions in
the first two, takcn from the continuity or interruption
of the striae and the presence of one or two stomatic
apertures. Much more naturally establishcd do we find
the nineteen families, (Eunotieae, Meridieae, Eragillarieae,
Mclosireae, Surirelleae, Cocconoideae, Achnantheae, Cyra-
belleae, Gomphonemcae, Naviculeae, Licmophoreae, Stria-
telleoe, Tabellarieae, Cosconidisceae, Anguliferae, Tripo-
disceae, Biddulphieae, Angulatae, Actinisceae ;) respecting
these we have seen that, in the actual state of Science, few
clmnges would be fully justified. Such clmnges appear
to me to be the following : — the union of Meridieae with
Eragillarieae ; the Separation of the genus Licmophora
from the family that bears its name, to join it with
Bacillarm and Synedrce in the family of Surirelleae;
to examine it again comparatively with that of Navi-
culeae, to decide upon the presence, constancy, and value
of the character of a median aperture, which alone serves
to separate thern ; the comparison, under this point of

ANIMAL NATURE OF DIATOMKjE. 493

view, of the Licmophoreae (excluding the genus Licmo-
phora) witb the Gomphonemeae ; the necessary fusion
into one only, of the two families Striatelleae and Tabel-
larieae, the character of median aperture given as dis-
tinctive of the second being absolutely false, with the
Separation of the genus Terpsinöe as a distinct type ; the
removal of the Coscinodisceae, and probably of the
Tripodisceae, among the Melosireae; the grouping together
of the three families, Anguliferae, Biddulphiese, and
Angulatae, excluding Lithodesmium as uncertain ; and
leaving there the genus Odontella, which demonstrates
the affinity of the entire group with the Melosireae ;
finally, the decided Separation of the Actinisceae from all
the other Diatomeae.

These changes being admitted, and the principle being
conceded, to its full extent, not to allow absolute value to
any character taken separately, the Diatomeae would be
divided into two sections ; the Actinisceae, and all others
tliat could be comprised under the name loricata, unless
we should refuse to acknowledge that the first (section)
have really any bond of alliance with the second, except
the siliceous nature of the dermo-skeleton. In the
loricatce it would be hasty to separate the genus Terpsinöe
from all the others, which might be reduced to eight
families only: — 1, Eunotieae; 2, Eragillarieae, (uniting
with thern the Meridieae, the Striatelleae, and the Tabel-
larieae;) 3, Melosireae, (comprising the Coscinodisceae,
Tripodisceae, Anguliferae, Biddulphieae, and Angulatae ;)
4, Cocconoideae; 5, Achnantheae ; 6, Cymbelleae; 7,
Naviculeae (with all the Surirelleae ;) 8, Gomphonemeae
(with all the Licmophoreae, except the genus Licmophora.)
These families, too, might be separated into two groups,
according as the temnogenesis takes place by simple
deduplication, (Eunotieae, Eragillarieae, Naviculeae, Gom-
phonemeae, Cymbelleae, and Cocconoideae,) or by redu-
plication , (Melosireae, Achnantheae.) I do not believe,
however, that this distinction is so essential as it may
secm ; for even in this case it appears to me that the

494

ANIMAL NATURE OE DI ATOMEN.

evident complication of tlie process in the second group,
proves the like of the apparently simple process of the
first. In fact, it is indeed always necessary that the two
new lateral valves of the two individuals be organised,
even in simple Naviculeae, and the Separation of the two
pre-existing always precedes the deduplication. It does
not, therefore, appear to me that we can entirely agrec
with Ehrenberg in what he adduces to distinguish the
process of deduplication ( sdoppiamento ) from regeneration
and reproduction. We cannot say that anything gives
way, wliere the formation of new valves appears, and
that the division is effectuated by that. The division
is merely the last stage of the process, and the per-
sistence of the two exterior valves does not seem to me
sufficient to prove that a total regeneration of the two
new individuals has not occurred. Nor can any one
prove that a reabsorption of organic substance and a
local renewal (riprisiinamento) of Organisation has not
taken place. And since the new parts which make their
appearance cliange the individual essentially, and do not
belong at all to its individual growth, as Ehrenberg
sagaciously observes, from this it clcarly follows that it
had previously ceased to cnjoy individual life. If I were
not afraid of appearing too transcendental, I would com-
pare the progressive deduplication (sdoppiamento) in the
Diatomem, with the successive development of the
terminal bud ( gemmci ) of the Sertularieae. This unfolds
itself (si sdoppia) into two organisms, which, in smaller
dimensions, might appear almost equal ; but one of these
enjoys an individual life, the other, again, becomes halved
(si sdoppia ), and so on indefinitely.

As respects the rank and position to be allowed the
Diatomese in zoological Classification, it results from the
observations hitherto collected, that nothing positive can
be asserted. No one, henceforth, will have a right to
contradict the authoritative opinion of Ehrenberg, who
ascribes them to the dass of Polygastric Infusoria.

ANIMAL NATURE OE DIATOME^E. 495

[Kiitzing lias recently published (‘ Botanische Zeitung,’
Bel of April, 1846, No. 14, p. 249) some new Diatomese,
discovered by Brebisson, at Falaise. An Achnanthidium,
a Gomphonema, two Naviculce, a Ceratoneis, two Synedrce ,
and a new genus belonging to the fanaily Striatelleae.

73. Pleurodesmium. — “ Trichoma articulatum fasciee-
forme , articuli plcini scepe yeminati, fascia transversali
media Injcdinci notati, ex sulcis lonyitudinalibus obsolete
punctatis ( perforatis ?) costcdi ; costis rugidosis.

And thus is corapleted the number of seventy-two genera
proposed (in the preceding ennraeration Kützing omitted
number 49 by mistake) ; and the number of species is
brought up to more than eight hundred.]

(Forfurther information in regardto tliese genera, and
additional ones since proposed by Kützing, see his
‘Species Algarum,’ 1849. — Ed.)

ANNOTATIONS.

Page 4. — Without engaging in controversy, rather to
show our high esteem for Kiitzing, we deem it necessary
to subjoin a few words, lest we should seem desirous of
eluding the question, or not duly weighing the reasons of
this excellent author. “ There do not exist in nature
definite ( scharfe ) boundaries between species, classes, and
kingdoms, and our having admitted these theoretically,
leads us to regard some inferior animal forms as plants,
and some vegetable forms as animals. The limiting of
the boundaries between the two organic kingdoms is
always a problem. All mctaphysics should be excluded
from the study of nature, in which we can only proceed
by the empirical way, and therefore we ought to restrict
ourselves to wliat we see, observe, and widerstand.”
These thoughts, expressed by Kiitzing, (‘ lieber die
Verwandlung der Infusorien in niedere Algenformen /
Preface,) are strictly logical. But the conclusion deduced
by the author is not legitimate, tliat we ought to admit a
common point of departure for the two kingdoms. If it
be absurd to admit the problem to be solved positively, it
is equally so to admit that it is decided negatively. The
contradictions to which he alludes, as produced by the
false supposition of the existence of a limit between the
two kingdoms, belong to authors or books, and not to the
Science. The very examples, the vibratile cilice of Surirella
Gemma (Ehrenberg), and of the spores of Vaucheria
clavata (Unger), have an answer in the observation of
Siebold. All the observations on the mobility of the
sporidia of the inferior Algse, of the spores of Vaucheria,

ANIMAL NATURE OP DIATOMEiE.

497

of the Zoosperms, of Sphagna, Charte , Marchantiece,
Eilices, and, lastly, of Fucacem, prove nothing more than
this, that vegetable beings, in certain stages of their
development, and in certain couditions, possess a mobil ity
that simulates animal mobility. It is a positive fact,
that the complicated animal Organisation discovered by
Ehrenberg in many of his polygastric Infusoria, cannot
be recognised in some that are referred by analogy to the
same dass ; but it does not at all follow, from this, that
we onght to regard these sporidia and the spores of
Algae as animals ; for, besides their want of this Organisa-
tion, they manifest an evidently vegetable nature by their
subsequent development. Neither onght we to deny an
animal nature to other beings in which this complicated
Organisation exists. The multiplication by division, or,
in other words, temnogenesis, is not, as Ehrenberg
believed, exclusively animal. By good right we admit it
in vegetables also. But is the organic process by which
it is accomplished the same in the two kingdoms? If
the character, in its generality, cannot serve for the dis-
tinction, it only follows that there is a necessity for further
researches in order to discover the peculiarities.

The Closteria, and Desmidiem, in general are plants,
and not animals. In the actual state of Science, we are
compelled to admit this proposition. The organic struc-
ture, the physiological phenomena, the history of their
development, the chemicalmaterials they contain, manifest,
in these beings, a perfect correspondence with others,
which, in every point of view, correspond with the ab-
stract idea of a plant. But vvhat they present in common
with other beings, evidently animal, is merely an appear-
anee, or, at the most, a resemblance, in external form.
Ehrenberg was misled by this appearance, and guided
by this fallacious similitude, thought that he discovered
in the Desmidiem, the same organic peculiarities which
proved the animality of other beings. Ought he to have
reasoned thus? ITowever, the most accuratc observer, and
the man of genius, is liable to error. Nor by this can

32

498 ANIMAL NATURE OF DIATOME/E.

bis merit ever be impaired, or tbe benefits lie bas conferred
on Science be diminished. Tbe loss will accrue only to
tbose wbo, disdaining tbe fatigue of observation, content
tbemselves witli tbe autbority of a master, and accept
indifferently bis real discoveries and bis errors. Heaven
be praised, tbe day of autbority bas passed away, and be
wbo bends to tbe yoke, may wander in peace, but Science
will not proceed tbe less, and may even derive advantage
from tbese errors. Erom tbe study of tbe Desmidieae,
and comparing tbem witli animals, valuable knowledge
on tbe intimate structure of vegetables bas been derived.

Tbe very beautiful observations of Elotow, lipon wliat
be terms Hcematococcus pluvialis, ' seem to prove its
animal nature. Nor does tbe appearanee of somc Algae
(determined by Kützing from tbe figures as Ulothrisc teuer -
rima, U. tc?iuissivia, Gloiodictyon viride, 8fc.) in tbe vessel
wbere tbe supposed Hcematococcus bad remained im-
merscd in water for some time, after baving been prc-
viously dried for fourteen montbs, certainly demonstrate
tbat tbese represent a different stage in tbe existence of
tbe same being. If such were tbe case, we must infer
from it, tbat in despite of all appearances of animal nature,
tbis Hcematococcus was really nothing but tbe germs of
some Algse, and therefore vegetable.*

Wc are led precisely to tliis conclusion by tbe still
more accurate and valuable observations of Kützing, on
tbe metamorphoses of Microglena monadina into TJlotlirix
zonata, and of Chlamidomonas JPulvisculus into Styyeoclo-
nium stellare. Some may raise a doubt whether tbe
globules, from which tbe filaments of Styyeoclonium are
developed, were precisely the same as tbose tbat moved
at first, and were furnisbed with a red spot and a
ciliary appendage ; and again, whether they were pre-
viously mixed together, and confounded witli tbe otliers,
owing to their resemblance in external aspect, or only
made their appearanee ( comparsi ) subsequently. But

* See the following paper in tliis volume. Also on Chlamidococcns and
Chlamidomonas in ‘Braun on Rejuvencscence. Bd.

ANIMAL NATURE OF DIATOMEiE. 499

still, admitting that we are treating absolutely of the
being that is regarded as an animal by the author,
and denominated Chlamidomonas , and that the Stygeoclo-
nium actually derives its origin from it, the conclusions
from this fact may be reduced to the following ; that the
germs of Stygeoclonium possess motions similar to
animals ; that they are provided with a red spot similar
to the eyes of Infusoria ; that they even sometimes possess
a terminal cilia ; sometimes a transparent space or an
aperture by which they fix themselves, to vegetate ; and
the supposed Chlamidomonas Pulvisculus is nothing more
than the germ of Stygeoclonium. As to the other or-
ganisms, as well animal as vegetable ( Tetraspora , Pal-
mella botryoides , Protococcus , Gyges, P andorina, Monas,
Gloeocapsa, 8fc ) which seern to have an origin similar to
that of Chlamidomonas, Kiitzing merely intimates their
similarity of form.

Our author rightly distinguishes the two methods
pursued in the study of organic beings ; to consider them
either with Linnaeus, completely developed, or with
Goethe, in their successive development. The definitions
of the forrner are derived from an empirical synthesis ;
I do not allow that such can only be arbitrary, because
no empirical idea can be defined ; for it appears to me
that we can know nothing more than we learn by our
senses, and therefore I rather believe all those definitions
to be arbitrary which are not logically empirical. The
history of the successive development of a being, ap-
proaches more nearly to the true idea that we ought to
form of it, not because that idea is absolute, for there
can be nothing in nature absolute to us who form
part of nature herseif, but because the notion or con-
ception of a thing is so much the less incomplete,
the more numerous the points of view are from which
we consider it. And thus, in examining the successive
stages of development, we always fall into arbitrary
error, for time has no interruption, and in this respect
there is an imperfection inherent in our nature ; for we

500

ANIMAL NATURE OE DIATOME/E.

want a measure for the fraction into which time, as well
as space, is natarally divided.

It is true that, in the study of nature, we ought to
proceed independently and abstractedly of any precon-
ceived idea, attending to phenomena only; but still it is
necessary to select these phenomena one from another,
to compare them, to separate those they possess in com-
mon, and those in which they differ, thus gradually
ascending to synthesis. Every metaphysical idea, as-
sumed a priori as the basis of a doctrine, is of necessity
arbitrary. But synthesis, logically executed and preceded
by the analysis of individual facts, leads us securely to
the attainment of knowledge. There may be error in the
observation, or in the deduction, but never in the method.

When Kützing, combating the principle of the exis-
tcnceof a precise limit between the animal and the plant,
concludes that there exists no such limit, he only Substi-
tutes one metaphysical principle for another, and therefore
wanders from the maxims laid down by himself just
before.

When he demonstrates that movements, and the
organs by which these are performed, are not exclusively
those of animals, and that there may be an appearance
of an eye, a stomach, and a mouth, in vegetables, he
controverts his own theory of a double nature, animal and
vegetable, in the same being.

The observed facts are valuable. They prove the
insufficiency of the characteristics given by authors to
distinguish animals from plants. And, even if it should
remain impossible for our most reinote posterity to
decide, whether given beings can, or ought to be included
in the abstract idea of a plant, or in that of animal, this
will not suffice to confound the two ideas, because their
empirical nature is relative, indeed, but not arbitrary.

Berhaps the most important observation of Kützing,
on this subject, is that of the different vital phenomena
presented by the most simple vegetables, according to
the prevalence in them of the external gelatinous (cellulose)

ANIMAL NATURE OE DIATOMKA5.

501

membrane, or of that internal one which he terms amyla-
ceous, and which is the primordial utricle (of azotised
quaternary substance) of Mohl. In this second case,
there are movements, and cilise by which they are effec-
ted. The sporidia of the lower Algse, the spores of the
Vciucherice , the spirilla of antheridia, the filaments of
Oscillariese, are either destitute of a gelatinous sheath, or
it is softened and almost dissolved. The air promotes
the development of the gelatinous substance, light and
heat that of the amylaceous.

Inseparable from the preceding quest.ion is that of
speciological and generic limitations. It is a demon-
strated and very important fact, that many organisms
described as species and genera of the inferior Algse, are
merely transitory forms of more complicated beings. The
consequence to be logically deduced, is the exclusion of
these supposed species and genera from the catalogue of
beings. He who desires to continue the enumeration of
them as such, ought, to be consistent with himself, to
establish species and genera even of the transitory forms
of all other beings in nature, unless he maintain that
the transitory forms of inferior organisms differ in this
respect from those of the superior, inasmuch as they
can persist as such, live, and multiply. I believe that
this position cannot be impugned even as respect.s the
most elevated organisms, since Teratology furnishes a
sufficient number of examples to prove the possible
permanence of every transitory form ; and in the inferior
organisms, multiplication is confounded with simple
increase. It would remain to be decided whether we
could always clearly distinguish reproduction from mul-
tiplication, and if so, whether we possess positive data
to determine the attainable point of organic perfection
of which every being is capable. But, since we are
oftentimes destitute of this secure criterion, we ought to
obtain data by observation, and to consider that develop-
ment to be the highest which is the highest we are
able to observe. Nor can any one assert that if develop-

502

ANIMAL NATURE OF DIATOMEJE.

ment be arrested at some intermediate form, this has
not occurred from the want of favorable circumstances,
and ougbt not to be considered transitory. As Mon-
strosities are classified, to facilitate study, or lead to the
attaimnent of general notions ( concetti ), so I allow that
the transitory fonns of the inferior organisms should be
classified, compared and, if you please, named systemati-
cally ; but that they ought to figure in the same rank
with forms permanently attained, and truly specific, I
can nevcr logically allow.

Page 7. — Some regard the epidermis as a product of
secretion, and therefore destitute of Organisation and
life. Recent inquiries as to secretions, prove that they
are accomplishcd by a process exactly similar to that of
nutrition and growth. The question is now reduced to
decide whether the product of epidermal secretion ceases
to live whilst it still forms part of the animal structure,
and when this change takes place. I am glad it is in my
power here to introduce a note I have received from the
learned Moses Benvenisto.

“ The epidermis, as well as the raorecomplicated parts,
which derive their formation from it, and possess cliarac-
ters and functions in common with it, is certainly orga-
nised. But this Organisation is of an inferior grade to
that of many other tissues, because it is simply cellular
and not vascular or fibrous. It is similar to the products
of secretion which abound in nucleate cellules, not elon-
gated into fibres, nor developed in canals j but with the
difference, derived in part from the contact of air, in
part from the action of absorbent vessels, that this external
secretion possesses no elementary liquid to maintain the
cells disaggregated, floating, and inflated ; hence result
only cells that are closely united, compressed, and disposed
in numerous superimposed layers. But I hold a middle
course between those who say that the epidermic sub-
stance is inorganic and dead, and those who will have it
to be existing per se, and living by a life of its own.
In my opinion it has an Organisation, and therefore a life,

ANIMAL NATURE OF DI ATOME®.

503

but of a low degree, and is also the product of secretion
from another more noble and complex element of the body
over which it is extended. What is this generating ele-
ment? This is a necessary inqniry, and not less impor-
tant than interesting to the physiologist and medical prac-
titioner. This element certainly forms part of the tegu-
mentary membrane, in which the epidermis constitutes
the ultimate layer and most superficial covering. I do not
believe that it can be the follicles or crypta, because these
minute organs afford mucus, oil, or cerumen, a liquid
adapted to lubricate, but not to organise, capable of
accumulation, but not of concretion ; for when once
covered with epidermis, we cannot conceive how their
apertures can still secrete oil {segö) or any other liquid
whatever ; so that if the cutis be considered as the same
with the mucous follicles, the epidermis is thin where these
are abundant, and, again, it presents the greatest thickness
where these are rare, or absent, as in the palm of the
hand, or the sole of the foot ; finally, because very often
in morbid thickening of the epidermis, we do not find
the follicles varying from their natural condition. But I
believe that the organs producing the epidermis, at least
in most places, and in most instances, are the papillse
which possess so many vessels of every kind, that we
cannot suppose them wantin g in the function of se-
cretion. And indeecl we observe that wherever the
papillae are most numerous, most developed, and most
vascular, there the epidermis is the most manifest. It
is thickest on the palms of the hands and the soles of
tlie feet, where, to serve the office of touch, the papillae
are most numerous, and are organised and arranged in a
particular rnanner. It is thickest on the tongue, where
the sense of taste requires an abundance and prominence,
of the papillary organs. And speaking of mucous mem-
branes, wherever they exist there also exist sensitive
papillae, animated by nerves of sense, that is in the
vicinity of the natural orifices of the body. According
to the most recent teachers of pathological anatomy, and

504

ANIMAL NATURE OF DIATOMEiE.

especially Professor Rokitansky, hypertrophy of the
papillse is detected beneatli the Condensed epidermis, in
inveterate ichthyosis, and in connnon warts. All accu-
mulations of epidermis whicli assume the form of scales,
spring from papillse developed in the form of cylinders,
villi, and rami. According to Cruveilhier, accidental
horn is a morbid prodnct of papillse of the skin, crovvded
together, and twisted into a papillary substance. But
with regard to hairs growing physiologically and patho-
logically, as well as to horn, whicli seems always to be
formed by an agglutination of the skin, we must remem-
ber that, as they are composed of two different elements,
one an external envelope of epidermic nature, and the
other, an oily medulla, varying in colour, so botli the
papillse and the follicles concurin their formation. Both
the one and the other are altered in different ways,
precisely according to their accidental, or pathological
production.”

As to the Organisation of hone, there still rcmains a
doubt with respect to the presence of saline particles
mineralogically deposited in the parietes of the bone-cor-
puscles ; yet it is proved, that in the numerous concentric
laminse that constitute the walls of bone canals, in the
radiating tubes that travcrse tliem, and in the bone-cor-
pusclcs themselves, the calcareous substance is in the same
condition as the proteine, with whicli it is found intimately
United.

Recent observations liave proved, wliat might reason-
ably be supposed, as to the sliells of Mollusca, that they
have a decidedly cellular structure, the lime, together with
proteine, constituting the walls of the cells.

We know that the same is true of the silex in the
epidermis of Gramineae and Equisetacese, and of the
lime in Corallines and other marine Algse.

Page 8. — “ A cosmical history of the universe, resting
upon facts as its basis, has, from the nature and limita-
tions of its sphere, necessarily no connection with the
obscure domain embraced by a history of organisms, if

ANIMAL NATURE OE DI ATOME/E.

505

we understand thc wcrd history in its broadest sense.
It must, however, be remembered, that the inorganic
crust of the earth contains within it the same elenients
that enter into the structure of animal and vegetable
organs. A physical cosmography would, therefore, be
incomplete if it were to omit a consideration of those
forms, and of the substances which enter into solid and
fluid combinations in organic tissues, under conditions
which, from our ignorance of their actual nature, we
designate by the vague term of vital forces, and group
into various Systems in accordance with more or less
perfectly conceived analogies. The natural tendency of
the human mind, involuntarily prompts us to follow the
physical phenomena of the earth through all their varied
series until we reach the final stage of the morphological
evolution of vegetable forms, and the self-determining
power of inotion in animal organisms.” (Humboldt
Cosmos, vol. 1, p. 348. Otte’s translation.)

Page 9. — Nägeli appears to me to have treated more
profoundly than any other modern author on the limits
of the two organic kingdoms, {Ueber die gegemc'ärtige
Aufgabe der Naturgeschichte , inbesondere , der Botanik.
II, Th. Zeitschr. für wissenschaftliche, Botanik. II Heft.,
1845.) But yet objection may be made as to the
differential character established by him, of a cellular
membrane, ternary in the vegetable, quaternary in the
animal : the primordial utricle of the permanent vegetable
cell in the Algse {amylid-cell of Kützing), which, like the
nucleus to which it is always connected, consists of a
quaternary azotised substance, is sometimes, perhaps, not
even accompanied by a ternary membrane {gelin-cell of
Kützing) ; the cellulose itself becomes permeated by nitro-
genated matter (Payen, Kützing); and finally, an abun-
dant ternary substance, isomeric with starch, is present in
the Organisation of animal beings, (Schmidt, Loewig,
Kölliker.) The Suggestion of Nägeli that the cliief
cause of animal sensibility and mobility, resides in that
characteristic (quaternary, azotised) quality of the cell-

506 ANIMAL NATURE OF UIATOMFAE.

wall, seems confirmed by the Valuable observations of
Kützing, alreacly referred to, respecting the mobility of
the inferior Algse, of sporidia, of spores, and spirilla. But
even if we admit this idea, we can deduce no other than
the following principle from the facts hitherto known.
The primordial vegetable cells (internal or naked pri-
mordial utricle), have, like animal cells, the wall con-
stituted of a quaternary azotised substance, and possess
a mobility similar to animal mobility. Yet there remain
material differences in the contents. But, if this were
110t so, if observation failed to detect a material difference
between the rudiments ( primär dia) of the twokingdoms,
no one, from that circumstance, would have a right to
maintain that the difference does not exist. When we
compare together the rudiments of plants, or those of
animals, do we find material differences corresponding to
the almost infinite varieties of form and Organisation whicli
ensue with successive development? It is necessary to
repeat, that our senses are limited, and that if we desire
to pass beyond those boundaries by powers of reasoning,
we may do this by no other means than reliance upon
other facts exactly observed. Taking advantage of in-
stances in whicli the power of our senses is improved, we
reason upon otliers where that power is more limited.
Tlius, in respect to the rudiments of organic beings, the
observation of their successive development proves that
even when those rudiments do not manifest material
differences to our senses, these still exist.

Still we ought, in every way, to be extremely cautious
in deducing anything from these observations whicli may
seem to prove the animal nature of vegetable germs, even
when tliey are made with great accuracy; inasmuch as
we can controvert them by otliers equally exact of a con-
tradictory nature. Such are those made by Nägeli upon
liis Conferva glomerata , var. marina, and upon the Achlya
prolifera. In the former, especially, he could trace the
entophytic development of the Bodo viridis , whicli, at a
certain period, almost exactly resembles sporidia, but

ANIMAL NATURE OF DIATOME2E. 507

does not at all participate in the successive changes that
tliese undergo in gerraination.

Page 10. — Nägeli has digested in an able manner all
the facts relating to vegetable movements. The first
series of movements is intimately connected with growth,
and in regard to this we do not possess sufficient data to
establish a general difference between the two organic
kingdoms. The second is referable to the different
positions assumed by various organs of plants linder the
influence of externa! agents ; and those movements are
explained by an accumulation of juices in determinate
tissues, excited by tliese agents, or by the elasticity of
the cellular membrane. The movements of individual
parts of certain organs are mechanically produced by the
desiccation or intumescence of various tissues. But still
the question remains almost untouched in respect. to the
locomotion of the inferior Algse, sporidia, spores, and
spirilla. The impulse communicated by endosmosis and
exosmosis, has certainly a large share in the phenomena ;
but, after all, there remains the fact of vibratile cilias,
which seem to take part in these movements.

Page 12. — The Protococcus and Gregcirina are beings
that .present the greatest degree of simplicity in their
permanent state. Though, down to 1842, 1 had limited
the genus Protococcus to those vegetable beings only
which really present the greatest possible simplicity, other
authors, and Kützing in particular, continue to insert
species of more complicated Organisation ; hence some
confusion is created whenever we refer to this example
of organic simplicity.

I admit into the genus Protococcus only thosevegetables
which, according to our means of observation, are reduced
to a simple cell. When the period of reproduction arrives,
the wall of this cell is either reabsorbed, or is lacerated,
and its contents are poured out ; the rudiments of new
individuals make their appearance, which are never visible
in the cavity of the maternal cell. The development of

508 ANIMAL NATURE OF DIATOME/E.

new individuals occurs, on tlie other hand, inside the
maternal cell of Chlorococcus and Hcematococcus.

The genus Gr er/ arm ci was proposed by Dufour, and
very well described by Siebold. Kölliker examined six
species {Die Lehre von der thierischen Zelle. Zeitschr. für
Wissenschaft. Botan. II Heft, p. 40.) They are simple
cells, containing very minute granules ( granelli ), small
drops of oil, and a central vesicle filled with a transparent
liquid, with a few oily drops, and a dark round nucleus.
They move by the expansion and contraction of the
cellular wall. Tlieir reproduction is effected by an endo-
genous cell-formation. The contents separate into two
globular portions, which accumulate around two nuclear
vesicles newly produced ; the meiubranes form round
the two globules, and thus arise two filial cells, which,
after the redissolution of the maternal cell, separate from
each other and begin to enjoy their individual life. The
same author supposes that some species of Bodo, Monas ,
Sjpirillum, Vibrio, &c., equally belong to this new family
of Unicellular Infusoria , but we liave no direct observations
to prove this.

Page 13. — Collecting together all that has hitherto
been observed as to the first origin of cells, the supposition
we are able to form is the following. The first elements
we are able to perceive are the so-called elementary
granules {(jranelli) in animals, and the mucous granules
in plants. These are very minute solid corpuscuJes, of a
quaternary azotised substance, capable of growth, but not
of multiplication, nor of ulterior development. In the
midst of these appear the nucleoli in plants. Around
every nucleolus, mucous granules collect together, forming
a species of crust. The body resulting from this is a
nucleus or cytoblast. Around this appears a membrane
of a quaternary azotised substance, which is the so-called
primordial utricle. lipon the external surface ol this,
a membrane of ternary composition, not azotised, is
organised ; this is the true cell-wall, which alone remains

ANIMAL NATURE OF DIATOMl'LE. 509

after the primordial utricle and tlie nucleus have dis-
appeared. Whatever may be the mode in which the new
cells appear, we may assert, on good foundation, that t'ie
previous formation of a nucleus is constantly followe 1
by the primordial utriöle, and in consequence by the
cellular wall. The uncertainty and variety are referablc
to the first formation of the nucleus, to the contents which
remain confined, or are successively formecl between the
nucleus and the primordial utricle, and to the mechanism
forming the cell wall. It is not yet decided whether this
origin of the cells is exclusively endogenous, or may not
even be exogenous. Recent inquiries as to the nature of
yeast, ( Hygrocrocis , Lejjtomitus, &c.,) seem to prove that
nuclei alone, or, perhaps nucleoli, may separately give
origin to cells. In such a case the mucous granules would
be foreign to the new plant, and would contribute irnme-
diately to its formation ; the nucleoli would be its germs.
Every one sees the difficulties that are to be encountered
in this research, the cautions that are to be used in
drawing conclusions from every fact observecl, and the
necessity of advancing always from the known to the
unknown. Ilence, in denominating the organic elements
which are before our eyes, we are not to commence with
what appears the most simple, but rather with that which
is decidedly organised and clearly characterised.

In animals, besides the solid elementary granules
already referred to, there are small vesicles incapable of
ulterior growth and reproduction. They are simple,
drops of oil enveloped in a stratum of coagulated
albumen, and may be imitated artificially. Other vesicles
are capable of growth, but not of multiplication. They
contain liquid albumen, and one or more oily drops, as,
for example, the vitelline vesicles. Perhaps they are
analogous to globules of Chlorophyll in plants, or those
of starch.

The nucleoli are vesicles similar to the preceding;
they consist of a contained fatty substance, and an
envelope of proteine. They are susceptible of growth

510 ANIMAL NATURE OF DI ATOMEN.

and multiplication, which takes place by division. Tlieir
original formation is as yet unknown. Tlie nuclei are
vesicles formed of albumen or fibrine, or perhaps of
caseine, containing, besides tlie nucleolus, an albuminous
liquid, oily drops, and elementary granules. The forma-
tion of nuclei is entirely obscure ; but it seems proved
that it cannot take place without the persistence of the
nucleoli. The nuclei are multipliecl endogenously, and
in consequence of the multiplication of the nucleoli.
The contents of the nucleus collect round the nucleoli
originating from the division of the primitive nucleolus,
constitute tlieir partial integument, and set thern free by
the reabsorption of the maternal vesicles. The nuclei
are not only capable of uniform growth, and of multiplica-
tion, but also undergo numerous modifieations, especially
conversion into fibre. The cells liave walls soluble in
acetic acid, and are, tlierefore, composed of a combination
of proteine, either simple, or penetrated witli horn,
gelatine, chondrine, calcareous salts, &c.; and they
contain, besides the nucleus, water, albumen, fat, ex-
tractive matter, salts, and other compounds peculiar to
the various organs.

Whether the formation of the animal cell be endogenous
or exogenous, it requires the pre-existence of the nucleus,
upon which the membrane begins to appear, which by
degrees separates and dilates, surrounding it, and holding
it adherent to a point within its wall.

More rarely, the formation of a cell takes place within
’ a collection of granules having a nucleus in its centre.
The gelatinous substance which superficially surrounds or
unites and amalgamates the granules, becomes coagulated,
so to speak, and is Consolidated into a cellular membrane.

These particulars are mostly taken from the work of
Kölliker, in which there may be found a critical analysis
of the physical and Chemical theories proposed by authors
to explain the facts adduced.

Page 16. — Nägeli gives an ingenious explanation why
the multiplication of cells is always endogenous in

ANIMAL NATURE OF DIATOME/E.

511

plants, and exogenous in animals. He supposes that
the qnaternary azotised substance acts catalytically on
the circumjacent materials to produce Organisation. In
animals, therefore, the cellular wall acts upon the extra-
cellular materials ; whilst in vegetables, the ternary gela-
tinous envelope being once formed, the catalytical action
of the nitrogenous portion is limited to the interior of
the cell itself. We areindebted to Mohl for the discovery
of cells that remain permanently limited to this membrane
alone, (so called amylid-cell,) and thus we find an ex-
planation consistent with this theory, and also witli the
facts recently observed in the development of yeast.

Though it be true that systematic distinctions are
always baffled by nature when they are based upon the
materiality of characters taken absolutely, it is yet true
that general laws admit of no exception, and that a single
one would suffice to destrov their generality. The
appearance of exceptions proceeds from the complication
in which natural facts occur, a complication that frequently
disappears, when, instead of characters taken absolutely,
we obtain a view of the organic and vital conditions
which give rise to them.

Page 20. — The Tabasheer of the Bamboo, which con-
sists almost entirely of pure silex, seems to be a product of
simple excretion, and therefore in its nature inorganic.
But in all other cases in which the presence of silex is
manifest in plants, as in the epidermis of Graminese,
Palms, and Equiseta, the part which it takes in the forma-
tion of the cell-wall is undeniable.

The stomatic cells of Equiseta merit particular attention,
both from the silex they contain, and the transverse striae
they present on the internal surface. This resemblance
to the shield of Diatomese might lead us to believe that
we onght to regard it as an argument for maintaining
the vegetability of the latter. I do not think that 1
ought to dwell upon such an objection ; I only notice it
because I would not appear to be, or preten d to be,
unacquainted with it. Yet it seems to me important in

512 ANIMAL NATURE OP DIATOMEiE.

another point of view, the apparent complication tliat the
simple cell- wall may assume when penetrated by silex.

Page 22. — In the description of DiatomeEe it offen
happens tliat the valves are confounded with the surfaces.
The surfaces are remarkably distinguished by established
characters into primary and secondary. In descriptions,
it appears to me right to admit, for the sake of brevity,
the denomination surface ( faccio ) for the primary, and
side (lato) for the secondary. But the valves clo not
exactly correspond to the surfaces. The lateral valves
are never absent ; they sometimes exist solely, as in
Pyxidicula and Podosira. In many cases, principally
in Achnantheae and Melosirem, the lateral valves are so
beut or curved as to form parts of the primary surfaces.

But the valves, which exactly correspond with the
primary surfaces, are seldom distinct; and perhnps even
where there is an acute angle for a boundary, as in
Navicida, we cannot say that there is a complete dis-
junction. In most cases, the two primary surfaces, and
therefore the corresponding valves, unite into a continuous
plane, with a re-entering curve. rJTie distinction of ter-
minal surfaces, very evident, especially in the Surirellem,
is most important. When there are distinct terminal
surfaces, the primary surfaces are very limited. But
fliese terminal surfaces may belong to the primary valves,
or the secondary, or lateral, lf we take the Eunotieae, it
seems evident tliat the more or less acute or obtuse
extremities belong to the lateral valves, and therefore
the two primary remain entirely separated. But in the
Surirellem, these seem again to belong to the primaries,
and to participate with them in the process of de-
clu plication.

Tage 23. — The solid products which, under the form
of incomplete diaphragms, project into the inner cavities
of Bidddphia and Terpsinöe , belong to the lateral valves.
I can say nothing of Climacosphcenia, but in the Isthmia
nervosa we have something similar, though less developed.
I tliink we may also refer the septa of Actinoptychus to

ANIMAL NATURE OF DI ATOMEN. 513

the same. Perhaps Terpsinöe may be placecl by tlie side
of Biddulphia in tlie Family of Melosirem, by the same
character. Their principal ditference from Vittae, is in
their transverse as well as longitudinal direction. The
Vittae belong to the primary valves as well as to the
surfaces. These peculiarities of structure are certainly
very important, because we must reasonably suppose that
they bear a direct relation to the internal Organisation of
these beings.

But if we consider that in the same genus ( Isthmia ),
we have two species very similar to each other, one of
which always presents those incomplete diaphragms,
whilst the other is always devoid of them, we are of ne-
cessity led to exclude this character from the basis of
Classification.

Page 25. — The colourless membrane, which connects
all the internal organs of Piatomeae together, constitutes
the principal portion of their bocly, as Ehrenberg has
well observed in many places. Its trausparency impedes
onr view of its Organisation. It seems that the vesicles
observed by Ehrenberg in some species, and supposed to
belong to the male organs, were directly hollowed out of
this substance. Their dilatation and contraction seem
rather to indicate a respiratory function. I believe the
tube that runs longitudinally from one extremity of the
Naviculae to the other, and perhaps represents their
organ of digestion, to be hollowed ont, in like manner,
from this substance, and void of a proper membrane.

Page 90. — In the Ceratoneis Fasciola, Ehrenberg
describes and figures a distinct median aperture in the
centre of the lateral surfaces.

Page 106. — Kü.tzing, in the Phycologia Germanica ,
assigns to the Naviculm of Micromega pallidum , instead
of of a line, ±ih = 0-034'".

33

V

ON THE

NATURAL HISTORY

PROTOCOCCUS PLUVIALIS.

By FERDINAND COHN.

[Abstraeted from 11 ic ‘Nova Acta Acad. Cecs. Leop. Carolin. Natur»,
Curios. Bonn/ tom. xxii, pp. 605 — 764, 1850.]

By GEORGE BUSK, F.R.S.

ON THE

NATURAL HISTORY

OF

PROTOCOCCUS TLUVIALIS, Kutz.

Hcematococcus pluvialis, Flotow.

Chlamidococcus versalilis, A. Braun.
Chlamidococcus pluvialis, Blotow and A. Braun.

The author commences his paper by referring to the
observations of Plotow, on the same subject, under the
name of Hcematococcus pluvialis, (‘Nova Acta Ae. C. L.
C. N. C.,’ vol. xx, p. 11,) and to which he assigns the
highest merit. He proceeds to give an abstract of
Plotow’s observations as an introduction to his own.

However various the metamorphoses undergone by the
Hcematococcus in the course of its development, they
may, nevertheless, be referred to two principal forms, —
the still and the motile. The former, II. pluvialis quies-
cens , forms a sort of crust on the margin and bottom of
the vessel in which it is kept ; the other, II. pluvialis ,
swims abont in the water.

The motile form is from 0'0003 to 0-0012 of a Paris
inch in diameter, and consists of a colourless mucous
envelope, probably open in front, within which is con-
tained the true mother-cell, and which is either centric
or excentric. The contents of the latter are grumous
and vesicular, and either altogether of a carmine red

518

THE NATURAL HISTORY OF

colour, or of one inclining to bloocl red or green, witli a
central, multiform, red nucleus; seldom altogether green.
The mucous envelope is frequently wanting, or is so
closely applied to the cell as to be scarcely apparent.
The red nucleus appears to liave a special coat, which,
however, probably does not exist ; it appears as a liollow
vesicle, placed on or near to the inner surface of the
wall, and presents on one side an opening, or, only
half or two thirds of it may exist. The nucleus is de-
tached by pressure, and in the spot where it was situated
appears a colourless vacuity. The anterior extremity of
the mother-ccll exhibits either nonc, or cobweb-like pro-
cesses, which are but seldom apparent, particularly in the
globular or ellipsoidal forms which represcnt II. pluv.
rotundatus . Or there exists, at the anterior extremity, a
wart-like transparent process, from which arise simple or
bifurcate, filamentous elongations or tentacles, as in the
form II. pluv. papillatus. Whcn this process is conical
and attenuated we liave II. pluv. rostellatus. Not un-
frequently short setose hairs spring from the periphery
of the mother-cell, Stretching across the space between
this and the mucous envelope, and which characterise
II. pluv. seliger.

These motile forms, which may be coraprehended
under the common name of II. pluv. versatilis, are trans-
formed into the still form, becoming round, and retracting
the various processes above noticed ; whilst the mucous
envelope is Condensed into a papyracous membrane.

This still llcematococcus jjlitvialis, quiescens, aquaticus,
genuinus , from 0-0001 to 0 0029 Paris inch in diameter,
forms loose masses without its being retained, however, by
any special mucous hypotliallus. It sometimes has, and
sometimes has not a mucous envelope ; the mother-cell is
either entirely filled by the sometimes grumose-granular,
sometimes grumose, or even gelatinous contents, so tliat
the boundary line is reduced to capillary thickness or is
completely obliterated ; or it is only partially filled, and the
contents then form a smaller and, most usually, central

PllOTOCOCCUS PLU VI ALIS.

519

globular mass, which is probably contained in a second
cell. This was evident, however, in only one case.

As more intiinate constituents of the contents, botli in
the still and in the motile form, numerous more minute
spherules are to be considered. The red formative
material is to be referred to the sphere of fructification,
the green to tliat of Vegetation. Consequently the green
spherules in Hamatococcus must be regarded as gern
gramdes , or gonidia, which, when larger and internally
organised by a cell nucleus, become green gemmules.
When these gemmules, in the form just described, escape
from the mother-cell, they resemble the innumerable
dependent forms commonly associated under Protococcus
Monas; they exhibit an instance of retrograde meta-
morphosis, producing a succession of similar organisms,
which, shooting out in succession in a longitudinal direc-
tion, constitute confervoid filamentous forms, or, sprouting
out, expand into Ulva-like growths. Amongst the latter,
one is very remarkable, foliaceous, of a quadrangular
figure, consisting of many cells, which, like a simple
Heematococcus cell, is carmine red in the centre and
green towards the margin.

The green gemmules, however, are capable of pro-
gressive development, destined to reproduce the Hcemato-
coccus at once, when, for instance, the individual to which
they belong possesses sufficient red formative mucus
for its penetration and fructification. This is apparent
from the circumstance tliat the two-coloured, still forms
which are entirely fillcd with red and green gemmules,
in process of time become altogetlier red. And in this
case the red coloration gradually extends from the central
nucleus, as its original seat, towards the periphery,
whilst in the retrograde metamorphosis the red colora-
tion of the globales proceeds from without to within.

In whatever way the spores forraed of this red sub-
stance escape, they develop themselves, and at an un-
favorable time of year and dormant condition of vitality,
float, in flocculent aggregations, on the surface of the

520

THE NATURAL HISTORY OF

water. They then increase in size, become organised
internally, and surrounded witli a membrane derived
from a thickening of the peripheric layer of the spores.
They are tlius transformed into II. pluv. atomar iu-s,
whicli, in the course of further development, becomes of
a rose-red colour and gelatinous, surrounded witli a
mucous envelope, and constitutes the form of H. pluv.
mucosus ; whicli is finally transformed again into the
normal form. The dispersion, therefore, of the red
spores is not a proceeding without object, or a morbid
process, but subservient, in an incredible degree, to the
multi plication of the plant.

In a favorable season, and wlien the vegetative powers
are in full activity, the spores, after their expnlsion,
remain adherent to eacli othcr, connected by a mucous
material, afterwards becoming free, and successively trans-
formed into the motile form of Hcematococcus.

Another motile form is of a smaller size, distinguished by
its active motion, and characterised as II. pluv. porphyr o-
ccphalus. It has a flask-like or obovate form, 0 0002 —
0 0004 Paris inch in length, witli a red capitate projection
at the anterior extremity, and ventricose posteriorly.

In general, from the motile condition all these forms
pass immediately into the still form. But the alterna-
tion between the still and motile forms depends alto-
gether upon external conditions, and is by no means
capricious. Whether the still form, upon its division,
develop motile individuals, depends upon the light and
temperature.

Multiplication by division ( status viviparus) occurs
both in the still and in the motile forms. The contents
of the mother-cell, surrounded by a mucous envelope,
divide into four (frequently more) portions, eacli of
whicli includes a central particle of red matter, and sur-
rounds itself witli a gelatinous membrane.

The division frequently commences in the motile con-
dition, and continues in the still. The younger indi-
viduals, witli red mucous globules, spores, buds, and

PROTOCOCCUS PLUVIALIS.

521

green gonidia, and consequently furnished with all the
requisites for existence, bürst the mother-cell, and become
free. Should they belong to the second generation, and
consequently arise from the division of already motile
cells, the young individuals frequently remain in con-
nexion, and revolve together until at last they become
detached from each other. From this circumstance
arise aggregations of 4, 5, 6 minute globules ; even 8
individuals occur together in a mucous envelope. Some
cells divide even into 12 or more, and revolve in com-
mon like a Volvox.

Other forms of division are noticed. Besides this
mode, multiplication by gemmation takes place, both in
the still and motile forms ( innovatio ). Within the

mucous envelope tliere is formed a parietal, colourless
vesicle, into which the red atoms pass from the mother-
cell, and thus gradually colour the young individual.

The author proceeds to describe the effects of desicca-
tion, &c., upon the appearance and colour of the varieties
of Hcematococcv.8 , and notices the extraordinary power
of vitality after desiccation for many months, when the
Hcematococcus has been slowly dried ; and even after
quick dry in g, it would seem that development is possible
by rneans of spores and gemmules from the form named
II. atomarius. And even in some cases after such indi-
viduals had been swallowed and evacuated by Infusoria,
for instance, by Philodina roseola. Even momentary
exposure to a boiling temperature does not destroy their
vitality altogetlier, thougli it. does so partially.

A summer temperature, however, very much pro-
motes the development of the Hcematococcus, so much
so, in fact, that occasionally all the stages are gone
through within eight days. Commonly, the motile forms
retain that condition only for a few days or hours. When
some in the motile form are placed in a glass of water,
within twenty-four hours a red border appears at the
margin of the water as it evaporates, consisting of still
vesicles undergoing division, whilst beneath it is a

522

THE NATURAL HISTORY OE

broader, greener, reddisli band containing the motile
individuals. The motions of the various forms of Hcema-
tococcus are then described, (p. 623,) and, from the
description, appear to be very like those of Euglena
viridis. In fact so rnuch so that Flotow himself com-
pares them with those of Astasia pluvialis, deeming,
however, that specics, whicli is either identical with, or
closely allied to Euglena , as an animal Infusorium. He
goes on to say, however, “ that there is no appearance,
in the Hcematococcus , of animal Organisation, particidarly
of a mouth, intestine, or stomach ; nor is the admission
of indigo into the inferior ever observed.”

Flotow considers that the source of the motion of the
globules of Ihematococcus is cpiite problematical.

Iiaving thus premised an abstract of the more impor-
tant points in Flotow’s researches, from whicli the above
are extracts, the author proceeds to detail his own obser-
vations, whicli he says are to be considered only as
supplementary, in a great measure, to those of Flotow,
whicli he regards as of the highest value.

On the 2d January, 1850, some particles of sand
containing Protococcus pluvialis whicli had been collected
by A. Braun, were placed in a deep glass vessel and
covered with snow-water. The first moving forms were
noticed on the 8tli of January. The Protococcus had
been in a dry state in the herbarium for two years.
Other experiments showed that this retention of vitality
endured through many years.

In his experiments the author found great convenience
in the employment of little glass vessels in the form of a
truncated cone, about two inches deep and one inch and
a quarter in diameter, with a flat bottom polished on
both sides. These little vessels were filled with water to
the height of two to tliree lines. It was only in vessels
of this kind that he was able to follow the development
of a number of various cells throughout its whole course.
Although he agrees in the main with the views expressed

PUOTOCOCCUS PLUVIALIS.

523

by Flotow, the author differs from bim, at the com-
mencement, in one important particular. Flotow looked
lipon Protococcus pluvialis as a multicellular plant, the
individual cells of which are held together by a common
parent vesicle. Although he does not express bimself
particularly with respect to the kind and mode of this
connexion, it may be taken that he regarded it some-
thing like that which obtains in Nostoc, or rather, per-
haps, like the structure of Polgcoccus punctiformis, Kutz.,
in which numerous cells are said to be surrounded by a
thin, common cell-membrane. (Kiitz., ‘Phycol. Germ.,’
p. 148.)

This view, however, is undoubtedly erroneous. The
P . pluvialis is in all its phases a unicellular plant.

The idea of a unicellular plant, as first propounded by
Nägeli, as a systematic principle (‘ Gattung, einzelliger.
Algen.’ Zürich, 1849,) does not apply throughout to the
extent in which he employs it. He certainly includes
under the term a number of genera, having a certain degree
of internal relationship, as indicated by the fact that pre-
vious phycologists had united them in large natural
Orders, ( Chamceplycece , Kg.; Ulvacece, Harvey; Palmelle ce,
Decaisne, Endlicher, &c.) On the otlier liand, the
definition of a unicellular Alga, “ that in it the indi-
vidual is a single cell,” is too wide or too narrow, (1. c.,
p. 1.) Too wide, because this definition may be applied
with equal right to other Algae, which must be reckoned
among the multicellular, such as (Edogonium , which is
a Conferva, or Prasiola, one of the Ulvaceae, as Desmi -
dium and Gallionella, or as Tetraspora , all of which are
dcclared to be unicellular Algae. Too narrow, because it
is only by straining the definition that such things as
Pediastrum , Sphcerastrum, which form definitely bounded
bodies, and many Palmelleee, can be included under it.
Just as little do the characters assigned to a unicellular
plant bear a comparative scrutiny. The unicellular Algae
are said — 1. to present merely a reproductive, and, nor-
mally, only a double kind of cell-formation ; this is, how-

524

THE NATURAL HI STORY OE

ever, contradictory to the doctrine of Alternation of Gene-
rations, which is extensively applicable among the organ-
isras in question. For it is only after a series of divisions
that the true reproductive formation of spores takes place.
And Closterium, orEunotia, which, after numerous divisions,
produce true spores by conjugation, differ from Spirogyra
and Ulothrix solely in this, that in the latter the parent-
cell, which connects each pair of divisional individuals,
being converted into a cuticular substance, is persistent,
wliilst in the formcr it is soon dissolved. Wlience it
is also incorrect to say — 2. that unicellular Algae are
normally separate and without organic connection, be-
cause the containing and interstitial gelatinous substance
should not be regarded as such. At all events I have
been unable to perceive any essential distinction between
the enveloping substance in Fragillaria and Mougeotict,
gcnera which are equally readily scparable into clistinct
cells, and in Nostoc and Apiocystis.

As far as this, therefore, I agree with the reviewer of
Nägeli’s observations, (in Mohl and Schlechtendars
£13otan. Zeit./ 1849, Nos. 41-45,) but when he goes on
to assert “that there are no such things at all as uni-
cellular Algae, and that each cell is only part of a System
of cells contained one within the otlier, (1. c., p. 801,) it
is impossible for me to coincide with him.

There are, undoubtedly, unicellular Algse, that is to
say, Algse, the fluid contents of which, sometimes con-
taining already organised particles, are enclosed in a
single, semifluid, nitrogenous envelope, and this again in
a cell-membrane, often consisting of several layers of
different kinds ; and which, moreover, possess the faculty
of dividing themselves into several secondary cells, for
the most part equivalent to the primary cell. To these
unicellular Algce belongs Protococcus pluvialis.

That this is the case is most clearly seen in the still
form, which is most distinctly characterised by its cell
membrane, a more or less thick, though always colour-
less, envelope. In sorne cases it is gelatinous, and then

PROTOCOCCUS PLUVIALIS.

525

surrounds the contents witk a broad, peculiarly refrac-
tive ring, (Fig. 33.) In cases where this tunic does not
exhibit a double contour line, it is manifested by tlie
dark and skarp border surrounding the contents, and
which, especially on the transition of the motile into the
still form, is the first and most certain criterion of the
incipient change. Thus it resembles the membrane of
many Protococcaceae and other Algae. It never secretes
true thickening layers on the surface. Although this
cell- membrane exhibits all the optical characters of one
composed of cellulose, I have found it impossible to
demonstrate the presence of that principle by means of
iodine and sulphuric acid ; it is not coloured by those
reagents even after the contents of the cell have been
expressed. But this does not show that the membrane
is not of a vegetable nature, because other Protococcaceae
behave in the same way ; nor can cellulose, by those
reagents, be shown to exist in Oscillatoria, Nostoc ,
Merismopadia and other unicellular Algae.

The still cell always assuines a deep, almost black
colour, upon the application of a watery solution of
iodine ; but this does not depend lipon the coloration of
the cell-membrane itself, but upon the circumstance that
the nitrogenous contents, coloured by the iodine, are
seen through the transparent tunic.

The contractility of the contents when exposed to the
action of acids or alcohol, proves that they are endowed
with the same properties as the primordial utricle of Mohl,
the amylid-cell of Kiitzing. But there is no evidence of the
existence of any special layer of the contents, which could
be exclusively designated as a “ primordial sac ■” it would
much rather appear as if the entire contents of the cell
( endochrome of authors), in most cases, were to be regarded
as essentially homogeneous, and that it is only the outer-
most, for the most part densest peripheral portion of them
which possesses the faculties, which in other plants, par-
ticularly in the large-celled Algae, appertain to an also
optically distinct layer. ( Vide ‘ Ueber die Rotation des

526

THE NATURAL HISTORY OF

Zellsaftes/ in Nitella flexilis ; by Göppert and Cohn,
Botanische Zeitung, 1849, No. 37 — 40.)

There are, however, phases of development in which
the colourless or almost aqueous cell-contents can be dis-
tinctly defined from the denser, coloured, gelatinous,
peripheral substance. Whilst, therefore, in most cases,
the still form, according to Ivützing’s terminology, would
liave to be regarded as hologonimic full-cells, in which
the solid contents completely flll the cell, so, when the
primordial sac and cell-juice are separated, tliey would
nccessarily come undcr the denomination of calogonimic ,
hollow cells.

The contents Vary very much in consistence, colour,
and solid constitucnts.

The red and green portions of the contents appear to
be of equal physiological importance.

The green colour is removed by ether,on the evaporation
of which solvent there remain green, aftcrwards colour-
less drops. Dilute sulphuric acid at first renders the
colour paler ; but its prolonged action produces a bright
verdigris hue, which gradually becomes more and more
intcnse, and often almost a blue green. Hydrochloric
acid has a similar eflcct ; a tinge of brown is produced
by nitric acid. Carbonate of potass scarcely aftects the
green colour; it is gradually but totally destroyed by
caustic potass, the contents at the same time swelling
and becoming transparent.

The red colour is also to some extent soluble in ether,
but is less affected, or scarcely at all by any of the other re-
agents above enumerated. It differs, therefore, from the
erytlirophyll or the acidified anthocy anine of chemists, as
well as from the colouring matter of litmus and phycoery-
thrin, which, according to Kützing, is peculiar to the Blo-
ndem. In its Chemical relations it seems most nearly allied
to the phycohacmatin of Bgtiphlaa tinctoria, but the latter
is insoluble in ether. It also seems to be related to the
orange coloured oil, which, according to Nägeli, is formed,
under morbid conditions, in many unicellular Algae.

PROTOCOCCUS PLUVIALIS.

527

The contents of cells which have been long dried,
generally assume an oily appearance. The oily material,
then resembles in every respect the red globules which
have been described as being oil, in various species of
CZiroolepus , such as C. oleiferum, hercynicum , velutinum ,
aureum , and Jolithus. Like the latter, also, it is capable
of becoming green.

The change of colour from green to red in Buglena
appears to be a process very n early allied to that which
takes place in Protococcus, if it be not identical with it.
Great confusion and much contradiction is evident in
nearly all writers who have referred to the subject of the
colouring matter in plants, and accurate researches on
the subject would appear to be of the greatest moment.

The red substance of Prot, pluvialis is not always of
an oily aspect ; it only becomes so in more advanced age.
Whetlier it really be oil, the author does not venture to
decide, although the relation of the material towards
light, alcohol, and ether (and he might have added,
water), are in favour of its being oil. And according to his
researches, oil is much more generally distributed thau
has been supposed, among the lower Algse ; occurring in
many true brown spores, such as of t 'Edogonium ,
Spirogyra, Vaucheria, &c.

When still or motile cells are brought in contact with
a very weak watery solution of iodine, they become
internally, in most parts, of an intense violet or blue colour.
The author, however, does not believe that this colour
actually, in all cases, depends upon starch, as in the
present state of chemistry it would appear necessary to
conclude that it did. He was satisfied that the red sub-
stance was invariably and entirely coloured blue. When
some of the cells were ruptured, all the previously red
globules had become entirely dark blue, so that the red
colour was wholly removed, whilst the green substance of
the cell with its granules was not so much altered, tliough
also bluish. The larger drops also appeared blue, so
that there was no difference whatever, in this respect,

528

THE NATURAL HISTORY OF

between tlieir reaction and that of starch, which also fre-
quently occurs in similar small globules. But that the
red, oil-like, or at all events, fluid substance, sliould be
actually identioal with the colourless, solid starch, which
always presents a definite structure, can scarcely be as-
serted. May there not, however, in the Vegetable king-
dom, be a coloured fluid, exhibiting the same reaction
with iodine, in all respects as starch ? If tliis be the case,
the infallibility of the blue reaction with iodine, as a cri-
terion of the presence of starch, would become question-
able ; and, particularly in the case of the unicellular Algae,
in which large-grained starch does not occur, would this
observation be of importance. Nägeli had noticed the
blue colour assumed by this orange-coloured oil on the
addition of iodine, especially when it was collected into
large blue-green drops by means of alcohoh*

Of great importance, moreover, is the relation of the
green and red colouring matters to eacli other. For,
notwithstanding tlieir different Chemical and physical
conditions, the one passes into the other, and vice versa .
The observations hitherto made on this subject, indicatc
that the red colour which normally is always formed as
the cells become drier, particularly in moist air, depends
upon a less Saturation of the cells with moisture ; is the
attribute in fact of a lower hydrate of Chlorophyll. But
that a deficiency of water is not the sole cause of the
change of colour, is proved by longer observations of the
Vegetation of Prolococcus. Nor does light either appear
to be the exclusive cause of this phenomenon, which
remains still in considerable obscurity.

With respect to the solid constituents of the Proto-
coccus cell-contents, they may be distinguished into
Chlorophyll vesicles, colourless or green granules, the
above-mentioned amylaceous granules, and the nucleus.

* The yellow oil, of which there is a considerable quantity, in the winter
spores of Folvo.r, (the so-called V. aureus , Ehr.,) is coloured blue-green by
iodine. — Ed.

PROTOCOCCUS PliUVIALlS.

529

The term Chlorophyll- veside (chlorophyll-blaschen) was
first introduced into the anatomy of the Algse by Nägeli,
although Meyen had previously expressed a similar view
respecting tlie structure of the Chlorophyll. Nägeli
regards them as rainute membranous vesicles, containing
a raucus coloured with Chlorophyll, only apparently pre-
senting the aspect of nuclei or liollow spaces, frequently
forming starch in their inferior, and which are found in the
Palmellacese, Desnndieae, Vaucheriaceae, and multicellular
Algse. In Prot, pluvialis, tliey present the appearance of
minute green rings, about 0-002'" in diameter, the in-
ferior being sometimes darker, sometimes more clear, and
frequently alniost opaque. They occur principally in the
green cells, to the number of one, two, three, four, or
more. Rarely observed in the red cells. They are
coloured dark brown or violet, by iodine. The author
supposed that in Protococcus they stood in connexion
vvith the division of the cell ; but could not determine
with certainty that their number corresponded with that
of the secondary cells. Klitzing looked upon them as
gonidia or cell-nuclei, assigning to them the function of
propagation of the individual; but Cohn does not coin-
cide in this view, though ignorant of their true nature
with respect to the life of the cell.

The sometimes colourless, sometimes green granules,
are very minute, none being more than 0‘001/" in size.
The colourless may be regarded as protoplasma- (mucus,
schleim-) granules, the green as Chlorophyll granules,
which latter must not be confounded with the Chlorophyll
vesicles.

Whether there be a true cell-nucleus in Protococcus ,
Cohn has not ascertained with complete certainty. It is
known, moreover, that in most of the other Algas, and par-
ticularly the unicellular, it has not yet been made out
satisfactorily, whether, in the first place, a nucleus does
occur, and if it does, what its function may be.

The presence of starch has above been statcd to be
doubtful.

34

530

THE NATURAL Hl STORY OF

Microscopical analysis, therefore, demonstrates, in the
still cells of Protococcus, whatever aspect tliey may pre-
sent, tbe following elements :

1. A closed cell-membrane ; 2. contractile, sometimes
colourless, sometimes green, sometimes red, cell-contents :
the latter in innumerable droplets, the tvvo former fre-
quently Condensed or separated into more solid granules ;
3. lastlv, onc or more Chlorophyll vesicles, and in certain
stages a cytoblast. All tliese elementary parts occur also
in the cells of other plants, and there is, consequently, no
difficulty in the referring of all such forms, when in the
state of rest (the special valuc of which is only sliown by
the history of their after-developmcnt) to the simple
vegetable cell.

This inquiry, howevcr, is far more difficult in the
case of the much more variously constructed motile
form.

This form was considered by Flotow to consist of a
larger parcnt vesicle, surrounding nmnerous smaller red
and green cellules, and itsclf again surrounded by a
mucous envelope, within which werc two tentacula, often
placed upon a beak-like projection.

The first thing ascertained by Cohn was the non-
cxistence of the mucous envelope. The optieal appear-
ances distinctly showed the existence of,not an enveloping,
at all evcnts fluid mucus, but of a solid mernbrane.

Although this Statement does not accord witli the
notions hitherto entertained witli respect to similar
appearances of an enveloping mucous layer in other
Algee — which has been regarded by Kützing as a gela-
tinous or mucous envelope, consistingof jelly (gelin), and
termed by liirn a gelatinous cell (gelin-zelle) or tube,
or sometimes amorphous gelatine ; and which has been
designated by Nägeli as an “enveloping mernbrane (hüll-
membran), who supposes its outer layer to consist of a
homogeneous, semifluid gelatinous substance, — Cohn
States, that at all events, in the case of Protococcus, a struc-
ture so abnormal and different to wliat exists in all other

PROTOCOCCUS PLUVIAL1S.

531

plants, does not occur. The central coloured globale,
lying in the colourless envelope, is certainly sharply
defmed, but not as in the still cells, surrounded with a
strong double contour line, but with a delicate simple one,
wliich gives it a peculiar soft appearance. Either by me-
chanical means, or by Chemical reagents, the internal
globular mass may suddenly be made to lose its contour,
and to spread so as entirely to fill the cavity of the colour-
less envelope. Erom which it would appear that the
internal globular body is not surrounded by any special
cellulose-membrane, but only by one readily destroyed
by Chemical or physical agency, probably nothing more
than a dense layer of protoplasm. Whilst, on the other
hand, the external membrane represents a true cell-
membrane, enclosing between itself and the coloured
substance a colourless, aqueous fluid, probably pure or
nearly pure water.

The motile form of Protococcus, therefore, consists, as
itwere, of two cells, one within the other, both of which,
however, difler essentially from the common vegetable
cell : the external having a true cell-membrane and
aqueous contents ; the other, or internal one, with
denser, muco-gelatinous, coloured contents, but without
a true, rigid (starre) cell wall. Colm proposes to call the
external transparent vesicle the “ enveloping cell” (hüll-
zelle), and the internal coloured one, the “ primordial
cell.” The term “primordial sac, or utricle,” which
nearest corresponds to this organism, can only be applied
to its peripheral layer, and not to that together with the
contents; and the term “amylid-cell” of lviitzing in-
volves a Chemical error.

Neither of these bodies are true, perfect cells, inasmuch
as the former wants the primordial utricle, and the second
is without the true cell-membrane. The two together
would represent the perfect cell; and the entire aspect
corresponds, externally perhaps, to a plant-cell in which
the primordial utricle has become detached from the cell-
membrane and contracted itself into a globular mass in

532

THE NATURAL HISTORY OF

the interior. Bat in the present case the course of
development is completely opposed to tliis view.

On the other side, again, the primordial cell corresponds
to the cytoblast of the common plant-cell, not only
because, like tliat, it is free, and for the most part excentric,
floating in the interior of the cell, but also in its relation
to the development of the cell-membrane, in which it
agrees in its function witli tliat assigned by the theoiy of
Schleiden and Schwann, to the nucleus, in the formation
of the cell-membrane.

The form of Protococcus, named by Flotow Ham. pluv.
vcrsatilis seliger (fig. 15), presents a . perfect analogy
bctvveen the primordial cell and the nucleus of the
common plant-cell. He states tliat the filaments which
proceed from the central mass to the peripheric cell-wall,
are tubulär, giving passage to the red molecules from
the central mass. These lilaments, however, which pro-
ceed from the outer wall of the primordial cell towards
the inner surface of the enveloping cell, correspond mor-
phologically to the so termed mucous filaments (sap-
streams) by which the cytoblasts are commonly retained
in the centre of tlieir cells. Tliat they also correspond
chemically witli tliese, is proved by the fact tliat they are
rendered more distinct by iodine, and tliat they can be
made to retract by means of reagents ; and, in fact, they
exhibit, in the course of development, peculiarities whicli
characterise tliem as consisting of protoplasm.

The existence of tliese delicate threads passing from
the central mass to the enveloping cell, and the appear-
ance occasionally of little particles liaving molecular
motion, serve to sliow tliat the contents of the enveloping
cell are not of a gelatinous consistence, but of an acpieous
nature. And the continuity of the primordial cell-wall
witli the filaments sliows tliat it is surrounded only with
a denser layer of protoplasm, and is not enclosed in a
rigid membrane of cellulose.

The form versalilis, therefore, of Prot, pluvialis is
to be regarded as a cell with clear acjueous contents, in

rUOTOCOCCUS pluvialis.

533

which a central, also cellular, raass of protoplasm, or a
primordial-sac-like organism, performs the part of a
nucjeus.

The most distinctive characteristic of the primordial
cell, and what appears to constitute its most essential
importance in the life of the cell in general, but particu-
larly in that of the Zoospore (schwärm-zelle), consists in
its being the contractile element of the vegetable or-
ganism, that is to say, that from an intrinsic activity it
possesses the faculty of altering its figure, without any
corresponding change in volume.

It was Ehrenberg who first asserted that there was an
absolute boundary between animals and plants ; finding
even, as he fancied he did, in the smallest of the former,
— the Infusoria, — which had previously been regarded
as mere unorganised masses of mucus, the same Systems
of organs as those by which the most highly-developed
animal is characterised, that is to say, distinct nutritive,
motile, vascular, sexual, and sensitive Systems. Siebold
called the existence of these organs in question, regarding
the Organisation of the Infusoria as a homogeneous pa-
renchyma, in which he recognised only a nucleus, and in
one division a mouth and oesophagus. Nevertheless he
asserted that plants and animals were essentially distinct,
and that there was no transition from one to the other,
the nature of the plant being always immotile and rigid,
whilst the animal possessed the faculty of contracting and
expanding its body. This contractility, he observes in
another place, is the only certain diagnostic character, all
others being invalid.

It is not, however, the animal organism itself which is
contractile, but only a single tissue in it ; all the rest, skin,
bones, and connective tissue, are as rigid or passive as
the vegetable membraric, or at most elastic ; in the higher
animals the muscles only are contractile, and only in the
lowest, viz. the Infusoria, the entire body.

Whence Ecker assumed the existence of a special con-
tractile substance, which sometiraes occurs in a formed

534

THE NATURAL IIISTORY OF

state, as a contractile cell or as muscnlar substance, some-
times amorphous, as in the boclies of the Infusoria,
Rhizopoda, and Hydroida. Kölliker confirmed tliis view,
and carried it out particularly in the caseof the Infusoria,
which he declared to be unicellular animals with a con-
tractile cell-membrane and contents.

The contractile substance is characterised by the fol-
lowing attributes : — it is homogeneous, or finely granulär,
transparent, of the consistence of albumen, gelatiniform,
soft, more refractive than water, but less so than oil ;
insoluble in water, but gradually decomposed ; destroyed
by caustic potass ; coagulated and contracted by carbonate
of potass, as well as by alcohol and nitric acid ; lmving
the power of forming aqueous cavities, which originate
either by the Separation of the water containcd in it, or
by its reception from without ; owing to which the
remainder becomes dcnser and more granulär; and,
lastly, it prcsents the appearance, in water, of contractile
drops, which movc like an Amcebci.

All tliese properties had already been observed by
Dujardin, in a substance of which the Infusoria and
Rhizopoda are principally composed, and which he
tcrmed “ Sarcodc the aqueous spaces or hollows he
named “ Vacuoles,” regarding tliem as the most cliarac-
tcristic feature of the substance ; these spaces had been
erronconsly regarded by Ehrenberg as stomachs.

All these properties, however, are possessed by that
substance in the plant-cell, which must be regarded as
the prime seat of almost all vital activity, but especially
of all the motile phenomena in its interior — the proto-
plasm. Not only do its optical, Chemical, and physical
relations coincide with those of the “ Sarcode,” or con-
tractile substance, but it also possesses the faculty of
forming “vacuoles,” at all times, and even externally to
the cell ; a property, it is true, which has for the most
part been hitherto overlooked or misinterpreted.*

* Sometimes, as in tlic zoosporcs of Volvox, these vacuoles exhibit
rhythmical contractions. — [Ed.]

PROTOCOCCUS PLUVIALIS.

535

These clear, aqueous spaces, the so termed vesicular
contents, are presented in all young cells, and play a
considerable part in cell-division, and the sap-currents ;
they are in all respects analogous to the vacuoles of the
sarcode, as already supposed by Meyen.

From these considerations it would therefore appear as
certain as it can be made by an empirical deduction from
the premises in such a subject, that the protoplasm of
Botanists, and the contractile substance and sarcode of
Zoologists, if not identical, are at all events in the higbest
degree analogous formations.

Whence, the distinction between animals and plants,
viewed in the above light, must be thus understood ; that
in the latter, the contractile substance, as the primordial
utricle, is enclosed within a rigid, ligneous membrane,
which permits only an internal motion, evidenced in the
phenomena of circulation and rotation ; while in the
former it is not thus enclosed. The protoplasm, in the
form of the primordial sac, is, as it were, the animal
element in the plant, in which it is confined, being free
only in the Animal kingdom. Or, to express the thought
broadly, the energy of the organic vital activity, realised
in motion, is especially connected with a nitrogenous,
contractile substance, which, however, in the plant, is
“ cribbed, cabined, and confined” by a rigid, inert mem-
brane, absent in the animal.

The above motile attributes belong eminently to that
form of the primordial sac to which the author has given
the narae of primordial cell, under which term he means
generally to designate that form of the primordial sac which
in itself assumes the figure of acell, and is either entirely
without any rigid cell-membrane, or at least may exist in-
dependent and isolated from it. Such is the case, particu-
larly in the Zoospores (Schwärm-sporen) of the Algm.

This is exactly the condition presented in the primor-
dial cell within the enveloping cell, in the motile form of
Protococcus pluvialis.

The colourless protoplasm often constitut.es by far the

536

THE NATURAL HISTORY OF

greater pärt of tlie primordial cell, whicli then appears
as an almost entirely colourless, sharply-defined globule,
owing to the fact that the protoplasm is invariably sur-
rounded, where it is free, by a sharp border, as if by a
membrane. It is only in the middle or at one end of
tlie globule that tlicre generally remains a deposit of the
grcen snbstance in the form of a ring or lateral mass,

(Fig- 26.)

The same colourless protoplasm occurs in all cells,
evcn where the othcr colonred substances are mucli
developcd ; especially does it always appear as a delicate,
almost imperceptible layer constituting the outer boundary
of the coloured primordial cell, the periphery of whicli
then becomes sharply defined, and as it were surrounded
bya delicate, transparent, membrane. (Fig. 16.) Besides
t.his, the colourless protoplasm seems to occur exclusively
at the anterior extremity of the primordial cell, where it is
produced into a conical elongation or beak. (Figs. 18, 36.)

The green substance appears sometimes as a tliin and
fluid, sometimes gelatinous, sometimes more solid mucus,
and is perhaps more abundant and better developed in
the motile tlian in the still form.

The red substance generally forms only a central mass
of greater or less sizc ; more rarely it constitntes exclu-
sively the contents of the primordial cell. It is interesting
to tracc all the stages of the transition from the green
into the red substance, and one stage or phase especially
has long been regarded witli great interest, in whicli
the red pigment is reduced to a single minute granule,
attached to the interior or to one side of the primordial
cell, then representing what is described by Ehrenberg as
the “ red eye spot” of the Infusoria, and which was dis-
covered by Kützing, Fresenius, and Thuret,- in the spores
of Algse.

The three substances just considered present themselves
in the form of colourless, red, and green globules,
granules, and drops ; but besides these, the primordial
cells contain, at tirnes, vacuoles, chlorophyll-vesicles,

PROTOCOCCUS PLUVIALIS.

537

starch, and larger colourless granules of unknown ma-
terial.

The so termed “ vacuoles” occur, in greater or less
number, in the interior of tlie primordial cells ; they must
be regarded as clear aqueous secretions from the colourless
or coloured protoplasm, which is consequently forced from
the centre of the cell towards the periphery. They are
formed, and change, both in number and figure, linder
the eye of the observer, and present the aspect of large,
hollow, clear vesicles, which have the effect of causing
the coloured contents to appear frothy (Eigs. 21, 27) ; and
they are frequently developed in such number, that the
coloured protoplasm seerns only like a green deposit
on the wall, and even there to be wanting in parts. By
them it is that the internal watery cell-contents, as in the
common plant-cell, become definitely separated from the
more dense peripheric protoplasm (the primordial utricle).
The chlorophyll-vesicles resemble, in all respects, those
already described in speaking of the still form. They
are occasionally wanting in every form of cell, but gene-
rally so in the more minute, one or two-coloured pri-
mordial cells. (Fig. 41.)

By starch granules are meant, in this case as in the
still cells, very minute, colourless, strongly refractive
particles or granules, rendered blue by iodine, and which,
on the first appearance of the contents, are present in
great abundance in certain stages.

The colourless granules, which were met with only on
one occasion, in almost all the cells in the vessel, espe-
cially in the smallest, were highly refractive, spherical,
transparent corpuscles, visible through the coloured con-
tents. They were neither coloured nor changed by iodine,
acids, or alkalies. They resemble similar corpuscles
which occur in Euglena viridis at certain times.

The author then proceeds to describe the infinite
variety in appearance of different individual cells, owing
to the varying quantities or arrangement of the elements
al)ove described ; almost the only part of a motile Pro-

538

THE NATURAL III STORY OF

toeoccus cell which is alike in any two individuals being
the enveloping cell.

The anterior projection, beak or rostellura, is always an
immediate Prolongation of the colourless protoplasm,
forming the outermost boundary of the primordial cell,
but into which, speaking generally, the coloured sub-
stance is not continued.

Tlie contractile movements of the primordial cells is
usually very slow, but occasionally more rapid, in that case
very closely resembling those of Euglena viridis. These
more rapid changes of figure and appearance, take place
particularly upon the partial evaporation of the water in
which the cells are contained. But if tliis evaporation
proceed further, and fresli water be not added, further
and more important changes take place in the primor-
dial cells of Protococcus pluvicdis , which may be com-
prehended under the t.crm of “ deliquescence.” Tliis
process is exclusively characteristic of the vegetable
primordial cell, particularly in all zoospores on the one
side, and also in the Infusoria on the otlier.

The phenomena in question present two stages or
phases. In the first, the outlincs appear less sharply
defined, because the colourfcd substance is somewhat
retracted frorn the border of the primordial cell. It
is tlien clearly evident that the colourless protoplasm
constitutes the special smootli boundary membrane of
the primordial cell. The cells become flattened, and at
the same time wider. The contents also are now
altered ; previously more homogeneous and transparent,
they now become throughout granulär, and the red sub-
stance runs together into large drops. At tliis time
commences the formation ol vacuoles, the number of
which continues to increase. In tliis way the interior of
the primordial cell again becomes colourless, clear as
water, and the granulär, coloured contents, compressed
against the walls. The figure of the cell, in the mean-
while, is so mucli expanded that it comes to be applied
upon the wall of tlie enveloping cell, ultimately filling it

PROTOCOCCUS PLUVIALIS.

539

altogether, (Figs. 27, 28,) so that the entire zoospore
appears to consist of only a single, coloured, granulär,
vesicular disc, corresponding in size with the original
enveloping cell.

The Protococcus pluvialis has true motile Organs,
namely, two long vibratile cilia arising from the pri-
mordial cell, and which, passing through two openings
in the enveloping cell, move about in the water. These
Organs, during the life of the cell, move so rapidly that
it is theri difficult to perceive them ; they are only
recognisable by the currents they produce in the water.
But when the motion is slackened they are evident
enough. They are also rendered very distinct byiodine.

They are always placed upon the extreme point of the
conical elongation, on the anterior end of the primordial
cell, and in such a manner as to appear to be immediate
continuations of its substance, and as that process itself
consists of protoplasm, it is evident that the cilia must
be regarded also as composed of the same substance.
They appear in some cases to possess an adhesive pro-
perty. They resemble, in fact, in all respects, the so-
called proboscis of certain Infusoria, such as Euglenci and
the Monades, and not to differ organologically from the
non-vibratile but retractile filaments of Aconita and
Actinoplmjs.

It is only that portion ofthe vibratile filaments beyond
the enveloping cell that exhibits any motion, the portion
within the outer cell is always motionless, and in that
part of their course the filaments appear to be sur-
rounded with a sheath. This seems to be the case,
not only from the greater thickness at that part, but
also from the circumstance, that when, from the pas-
sage of the cell into the still condition, the cilia dis-
appear, the V-shaped, or forked internal portions remain
visible. And it is then, also, that the openings through
the enveloping cell become, for the first time, visible
(Fig. 4G.) Such are the “ encysted zoospores” (umhüllte
Schwärm-zellen.)

540

THE NATURAL HISTORY OF

There are, however, forras in wbich the enveloping
membrane cannot be distinguished at all, and in general
does not exist : these fonns are designated “ naked
zoospores” (nackte Schwärmzelle.) They are true pri-
mordial cells ; tliat is to say, their external boundary is
formed of nothing but the contractile cell-contents, or
protoplasm ; a true, solid, and rigid vegetable cell-
membrane is wholly wanting. They tlms correspond in
their structure with the zoospores of most of the other
Al gs e ( Vaucheria , (Edogonium , &c.) These naked zoo-
spores originate in various ways, and belong to various
stages of development. The following varieties of this
kind of primordial cell may be distinguished.

1. Those which differ from the encysted only in the
absence of the enveloping cell. This form corresponds
with the younger condition of the encysted zoospore,
nrising from the division of the cell, around which the
enveloping cell is not yet formed.

2. An other form arises immediately from the still cell,
distinguished by its verrucose figure, and its, for the
most part, cinnabar red colour. It is of small size,
and, narrovv in shape (Fig. 32.) On “ deliquescence”
taking place, the primordial cell bccomes expanded, and
at the same time flatter and of a lightcr colour, the
coagulated red droplets exhibiting a lively molecular
motion in the interior. In this case, also, large colour-
less vesicles are then developed in the interior.

In certain conditions, this form of primordial cell
resembles, in its form and aspect, the genus Aslcuici of
Ehrenberg.

3. Are very minute naked zoospores, not more than
0-002/// to IF005'" in size, mostly globular. They con-
tain Chlorophyll granules and red droplets, more rarely
chlorophyll-vesicles, and colonrless granules of unknown
nature, as described above (Fig. 41.)

4. Perhaps the most remarkable of all the numerous
aspects presented by Protocuccus pluvialis, is the form of
naked zoospore named by Flotow Hamatococcus porphy-

PROTOCOCCUS PLUVIALIS.

541

rocephalus. It is in the form of extraordinarily minute
(from 0-0015"' to 0-004'//) globules, consisting of a green,
red, and colourless substance (protoplasm) in unequal
proportions. The colourless protoplasm, in these, as in all
primordial cells, constitutes the outermost delicate boun-
dary ; the red substance is for the most part agglome-
rated towards the anterior end in minute spherules, the
granulär green substance occupies more the under part,
whilst the middle is most usually colourless. The shape
varies extremely.

Hence it is apparent that the naked zoospores, although
as regards their development not of equal value, are all
constructed in an analogous manner, varying only in
their mutable form, size, and colour. But they are all
true primordial cells, which before desiccation und ergo
deliquescence, having no rigid, solid, ligneous membrane,
being enveloped only in a mutable layer of protoplasm,
and with colourless green and red contents, in part
organised into granules and droplets, rarely containing
colourless granules of unknown nature, and Chlorophyll
vesicles, and always moved by means of two longer or
shorter vibratile filaments.

Having thus gone over the anatomical description of
the various forms of Protococcus, the author proceeds to
the history of its development.

1. The Protococcus jjluvialis is a unicellular Alga, a
simple cell, or at least the individual represcnts an
organism which exhibits the conditions of a simple cell ;
each multiplication of the cell reproduces the species, and
is at the same time an act of propagation ; each dissolu-
tion of the parent-cell into secondary ones constitutes a
new generation ; each secondary cell is an independent
individual of the same species.

2. The Protococcus jjluvialis is a plant subject to an
“ alternation of generations that is to say, the com-
plete idea of the species is not exhibited in it until after a
series of generations. The forms of development which can
be possibly compreheuded in the idea of the species, do not

542

THE NATURAL HISTORY OE

in reality make themselves apparent imtil a series of inde-
pendent successive generations bas beeil gone through.

3. The individuals of each such generation are capable
of propagating themselves in new generations. The
individuals of the second generation, are among them-
selves, spcaking generally, ofequal value; as respects the
individuals of the parent generation, they are sometimes
of equal value with tliem, sometimes not.

4. If the secondary cells are not of equal value to
their parent-cells, a series of successive generations must
precede the last generation, the individuals of whicli are
again equivalent to the first mother-cell. The numberof
these generations does not appear to be determinate.

Let. us assume that a parent-cell (a) has produced a
number of secondary cells (b) which are of unequal value
to their parent. The individuals of tliis second genera-
tion propagate a third generation equivalent to their
parent-cells (b) or not equivalent (c.)

In the first case there may also be a fourth generation
(b"), a fifth (b'"), and more, whicli are all equal among
themselves, and to their parents, but not equal to the
parent-cell of the first generation (a) ; until at last a
generation is produced which is not equivalent to its own
parent. Now tliis is eitlier equivalent (a') to the first
generation, and the cycle closes with it, or it is still not
equivalent to it (e). In that case, it eitlier propagates
again a number of equivalent generations, (c\ c". . .) or
lion-equivalcnt (d, e . . .) until at last one appears, a,
which is equivalent to the first generation, and tlius the
cycle closes. By equivalent, the author means such indi-
viduals or generations as correspond with each other in
their essential, physiological, and organological relations,
although they may differ in unessential properties, such
as colour, size, internal consistence, &c. Non-equivalent,
are those generations which in their structure and vital
relations exhibit essential differcnces, such as “ still” and
“ motile” cells, and among these, again, their various
forms ; but particularly those which are derived from a
different mode of propagation.

PROTOCOCCUS PLUVIALIS.

543

There is a large number of different modes of propaga-
tion in Protococcus pluvialis , which, indeed, are all
fundamentally analogous, but produce very different forms.

The main distinction depends upon the number of
divisional individuals produced from a parent-cell. Their
number appears always to be a sub-multiple of 2. A
cell may produce 2, 4, 8, 16, 32, 64 individuals.

The propagation depends upon a division of the cell-
contents, particularly of the colourless or coloured pro-
toplasm, or of the primordial sac. This body, without
any demonstrable influence of a nucleus, is capable of
subdividing into a determinate number of portions, in
the ratio just stated. Each of these portions acquires a
globular figure, in the next place surrounds itself vvith an
envelope of protoplasm, and then represents a visible
organism, which, after the resorption of the parent cell-
membrane, is capable of existence as an independent
reproductive individual.

The protoplasm which constitutes the extern al boun-
dary of this body, like all organised protoplasm, is
capable of secreting a rigid vegetable cell-membrane.
Two conditions now may present themselves.

1. Eit her, such a rigid, ligneous membrane is formed
within the mother-cell, around the portions of proto-
plasm separated by division as above, that is the pri-
mordial sacs : in which case there are produced only
still secondary cells, usually different in their structure
from the parent-cell. This process takes place only when
the parent-cell itself belongs to the still form, that is to
say, when the cell-contents or the primordial sac are closely
surrounded by a rigid, tough, ligneous membrane :

2. Or, the secondary individual, surrounded only by
a tunic of protoplasm, is liberated in this condition as a
primordial cell, and developes two vibratile filaments;
it then has the faculty of motion, and represents a naked
zoospore. This process may take place as well in the
Segmentation of still, as of motile primary cells. Here,
also, two conditions are possible.

544

THE NATURAL HI STORY OF

a. Eit/ier, tlie zoospore does not develop, during tlie
period of its motility, any rigid, tough, ligneous mem-
brane, but only when the motility has ceased, whereupon
tlie zoospore passes into the still form. This is the case
in the peculiar naked zoospores, of minute size, which are
produced in greater numberthan 2, that is to say, to the
liumber of 8, 16, 32, 64, frorn the parent-cell. They
cannot multiply until they liave assumed the still
form :

h. Or, the zoospore, during the period of its motility,
acquires a delicate but rigid membrane, which, liowever,
is separated (Vom the primordial cell by an aqueous fluid ;
it then represents the encysted zoospore . These are
capablc of propagation by Segmentation, reproducing,
liowever, only motile forms, although sometimes non-
cquivalent ones.

Bcsides this, the primordial cell in the encysted
zoospore may produce a second, rigid, tough, ligneous
membrane, around its whole periphery, by which it is
closely surrounded, whilst the delicate, outer enveloping
cell is removed. In this way the encysted zoospores pass
into the still form, and the cycle of possible developmental
forms is closed.

These appear to be the essential laws to which all the
plienomena attending the development of Protococcus
pluviolis may be referred ; and the author then proceeds
to particular instances.

It is difficult, from the numerous uninterrupted links
of a chain of plienomena, to select that which sliould be
regarded as the representative of the normal condition,
and to which all the rest might be referred; but, on
the other hand, it is indifferent where the commence-
ment is made, and the author therefore commences witli
the still form, which, within a rigid, tolerably thick,
ligneous membrane, indicated by a double contour
line, contains uniformly red, opaque, granulär contents,
contractile in alcohol, and presenting in the centre
a cytoblast (?) in the form of a lighter coloured vesicle

PROTOCOCCUS PLUYIALIS.

545

(Fig. 2). This form arises from tlic metamorpliosis of the
encysted zoospore into the still.

It may undergo changes, which may be distinguished
as essential and non-essential. The latter have reference
to the change in form and colouring of the contents ; the
former, to propagation.

The latter process takes place by the division or Seg-
mentation of the contents, at first as above stated, into
tvvo, then into four, eight, or sixteen, when the division
nsually terminates, and the segments pass into the motile
form ; although further still generations may arise in the
same way. The Segmentation takes place in the follow-
ing mode. In the first place the cell becomes elongated,
so that its diameter in one direction is twice as great
as in the other (Fig. 5). Then a constriction of the
contents is perceptible about the middle of the length of
the cell, which gradually deepens, and the cell contents
or primordial sac are divided into two halves (Fig. 6).
These are separated by a line which forms between
them ; and finally each is organised into a distinct
globule (Fig. 7), which becomes surrounded with a
ligneous membrane. The membrane of the parent-cell
is passive during this process — continuing, for a time,
to surround (sometimes in a gelatinous form) the secon-
dary cells ; it is finally dissipated, and they thus become
free. The part played by the supposed cytoblast in the
process of Segmentation is very doubtful.

During their dissolution, the cell-membrane of the dc-
funct parent-cells is gradually converted into a mucoid
substance, retaining the secondary cells more or less in
connected masses. In this way arises the Prot, pluvialis,
leprosus, of Fdotow. It is known also that other uni-
cellular Algae and Infusoria ( Chlamidomonas , Euglena ,
Monas , Vibrio , Zoospores, Diatomacese, &c.), under certain
circumstances, form similar envelopes, either by the
secretion of a mucoid substance, or the transformation of
their cell-membrane into such.

After a certain number of such divisions, all in the

35

546

THE NATURAL HISTORY OF

still form — usually after the third or fourth — the ultimate
segmeuts, instead of surrounding themselves with a lig-
neous membrane, become free, in the naked condition,
and developing the two motile filaments, represent a
motile primordial cell. (Fig. 12.)

The way in wliich the vibratile cilia are produced is
quite obscure.

The production of motile zöospores may take place on
the first Segmentation of the contents of the primary, still
form, or after the Intervention of an uncertain number of
such divisions as said before ; but it is clear that the
scgments of the contents of a still cell may at any time as-
sume the motile condition, and that their prolonged reten-
tion of the still form depcnds upon various external con-
ditions. But with division, on the other hand, it does not
appear possible for the still form to be changed into the
motile, wliilst the contrary may undoubtedly take place.

The production of the enveloping cell around the
primordial cell is then dcscribcd, as in a former part of
the paper; and the analogy between this process and
that of cell-formation, given by Mohl, Nägeli, Schleiden,
&c., pointed out. (Figs. 16, 17, 20, 21.)

The encysted zoospores, tlms constituted, grow for a
time very considerably, and after a certain time exhibit
a tendency to propagate, that is to say to divide.

The contents of the primordial cell (wliich alone is
potential in this act) exhibit lines of division into four
symmetrical portions, most distinctly sliown by the Chlo-
rophyll vesicles. Then, in directions corresponding to
these lines, the cell-contents are divided into four con-
tiguous portions, which gradually become isolated, and
assume a globular form, afterwards develope the two
vibratile cilia, and upon rupture of the parent-cell, be-
come free, and swim away. (Figs. 12, 13.)

A new enveloping cell is afterwards developed, and
these secondary motile cells become a seeon d generation
.of encysted spores, which, though in some respects unlike,
yet must be regarded as equivalent to their parent.

mOTOCOCCUS PL U VI ALIS.

547

Sometimes the enveloping cell is developed around each
secondary primordial cell, whilst still within the parent-
cell.

After a certain number of generations of this kind,
tlieir course is interrupted. A delicate double line is
perceptible around the primordial cell, which is the first
indication of the new, rigid, ligneous membrane, which
is formed around it (Fig. 46). The motile zoospore,
in other words, is again transformed into the still form.
The primordial cell is converted into a primordial sac,
and the cycle is closed.

Besides these, which are the most usual modes of pro-
pagation, viz. that of the still cells into two, and of the
motile, into four secondary cells ; there are a number of
others which may be considered as irregulär, and in
which forms are produced, which do not re-enter the
usual cycle until they have gone through a series of
generations.

The cell-contents, for instance, of the still form, instead
of dividing first into two, and then these again each into
two secondary cells, and so on, may at once be sub-
divided into four segments, as takes place in the motile
form. (Fig. 8.)

More frequently and regularly, under certain circum-
stances, the cell-contents of the still form divide at once
into eight portions, which become naked zoospores of
small size (Figs. 31, 32). It is not quite clear what
becomes of this form of motile zoospore, but there
seems reason for believing that they occasionally develope
an enveloping cyst, and thus become encysted zoospores,
and occasionally secrete a cellulose tissue and become
still cells ; but most of them probably perish without any
further change. They woulcl thus correspond with the
smaller motile spores observcd by Thuret and A. Braun
in other Algae ( Hydrodictyon , Achlya , the Fucoidese, &c.)
associated with the larger germinating spores, and which
themselves were deprived of the germinative faculty.

In the same way that the “ still” parent-cell may pro-

548

THE NATO R AL HISTOllY OE

duce, instead of two, eight secondary cells, so, on the
other band, may the motile encysted zoospore, which nor-
mally produces four secondary cells, divide into only two.
(Figs. 22, 23, 35.)

It appears tbat botli longitudinal and transverse divi-
sion of the primordial cell may take place ; but tbat the
vibratile cilia of the parent-cell retain almost to tlie last
nioment their function and their motion, after the pri-
mordial cell enclosed by it bas long been detacbed as a
wbole, and become transformed into the independent
secondary cells. (Fig. 38.)

The individuals of the secondary generation, wben the
encysted parent-cell divides into two, are for the most
part equivalent to their parent ; but sliould the latter
divide into more than two, its progeny tlien is very dis-
similar to it. For the encysted zoospores may also
divide into a generation of eight, sixteen, thirty-two,
according as the primordial cell has been partitioned
into eight, sixteen, or thirty-two portions, which become
organised into as many independent primordial cells.
The individuals of the secondary generation are of
course smaller, in proportion to the greater number of
parts into which the primordial parent-cell was sub-
divided, and they are also the more dissimilar to it in
proportion to the less quantity of its substance tbat they
may contain.

These minute zoospores, however they may originate,
are .always true primordial cells, and, under unfavorable
circumstances, perisli as such. What becomes ofthem
under other circumstances is not very easy to deter-
mine. It is certain, however, tbat they can pass into the
still form, assuming a globular shape, losing the vibratile
cilia, and secreting a ligneous membrane. They some-
times undergo this change while still within the parent-
cell. They thus constitute a mulberry-like mass, which
gradually mereases in size as the individual cells grow
(Fig. 40). They are also, after their liberation lrom
the mother-cell, sometimes seen to form an enveloping

PROTOCOCCUS PLUVIALTS.

549

cell around them, thus becoming encysted zoospores,
differing frora the larger form of that kind only in size
(Fi g- 41).

The author once observed four cells arranged as it
were in a cross, and connected to each other by the
anterior end (Fig. 25), and which, from their struc-
ture, appeared to be referable to the encysted motile
zoospore. It is a very remarkable circurastance, and one
difficult of explanation, that in this case each of the four
larger primordial cells was connected with each of the
two contiguous cells by two transverse processes, which
passed through the enveloping cell-membrane. In this
respect there was a resemblance to Chlamidomonas pul-
visculus and Trachelomonas volvocina, Morren, which re-
main connected by the beak or vibratile cilia. (‘ Recherch.
sur la Rubefact.,5 Tab. II, fig. iii b, Tab. V, figs. 9, 8.)
I think, however, that this condition is to be explained
upon the snpposition that four primordial cells have beeu
fonued within a parent cell by the usual mode of Seg-
mentation, but that instead of their being completely sepa-
rated from each other, they remain connected, and that
then, after resorption of their common, parent enveloping-
cell, also develope in the usual way special enveloping-cells,
which are of course in contact in the centre, and necessa-
rily assurne a cruciate figure. A smaller portion, which
in the Organisation of the segments was not taken into
any of them, has become an independent but more
minute primordial cell, lying between the arms of two of
the primordial cells constituting the cross. The above
process seems to be analogous to what takes place in
Gonium or Volvox, in which the individual segments,
after division, are retained in connexion.

Having thus gone over the various morphological and
developrnental conditions of the Protococcus, the author
proceeds to its biology.

The most striking of the vital phenomena prcsented
by this organism is that of periodicity. Certain forms,
for instance encysted zoospores, or certain colours, ap-

550

THE NATURAL HISTORY OF

pear in a given infusion, at first exclusively, then princi-
pally; they gradually diminish, become more and more
rare, and finally disappear altogether. After some time
their number again increases, and reaches, as before, an
incredible amount ; and tliis proceeding may be repeated
several times. Thus a glass wliich at one time pre-
sented only still forms, contained some weeks before
nothing but motile ones, and would again in a few weeks
contain nothing eise.

The same thing may be observed with respect to the
Segmentation. If a number of motile cells are transferred
from a larger glass into a small capsule, it will be found,
after the lapse of a few liours, that most of them have
subsidcd to the bottom, and in the course of the day,
they will all be observed to be on the point of sub-
division. On the following morning the divisional gcne-
ration will have become free ; and on the next, the bottom
of the vessel will be found covered with a new generation
of self-dividing cells, which again proceed to the forma-
tion of a new generation, and so on. Tliis regularity,
howevcr, is not always observed.

The infiuence of every change in the external conditions
of life, upon the propagation, is highly remarkable. It
is only necessary to pour water, from a smaller into a
larger, slial lower vessel, or one of a different kind, at
once to induce the commencement of Segmentation in
numerous cells. The same thing occurs in other Algae ;
thus the Vaucherice almost always develope zoospores,
at whatever time of year they may be brought from their
natural habitat into a room.

Light is conducive to the manifestation of vital action
in the motile zoospores, and they always seek after it,
collecting tliemselves at the surface of the water, and at
the edges of the vessel.

But, in the propagative act, on the contrary, and
when they are about to pass into the still condition, the
motile Protococcus-cells seem to shun the light ; at all
events they then seek the bottom of the vessel, or that

PROTOCOCCUS PLUVIALIS.

551

part of tlie drop of water in which tliey may be placed,
furthest from the light.

Too strong sunlight, as when it is concentrated by a
lens, at once kills the zoospores. A temperature of
undue elevation is injurious to the development of the
more active vital activity, that is to say, for the formation
of the zoospores; whilst a more moderate warmth, parti-
cularly that of the vernal snn, is extraordinarily favor-
able to it. Frost destroys the motile, but not the still
zoospores.

When kept in tlie dark, the zoospores become blanched,
that is to say tliey acquire a pale green colour, almost
without granules or red substance ; the chlorophyll-
vesicles, moreover, are not visible, so that the contents
of the primordial cell appear as a soft, homogeneous,
substance. The membrane is of a soft gelatinous con-
sistence ; the motile zoospores continue tlieir movement
uninterruptedly, without, as is usual, sinking to the
bottom, or passing into the still form, or into the stage of
Segmentation.

Under the influence of light, the cells give out a large
quantity of oxygen. It is perhaps the continued greater
evolution of gas by the motile spores, as compared with
those in the still condition, that causes them by pre-
ference to rise to the surface, and the latter to sink.

Stryclmine and morphine, even in the proportion of
1 part to 150 parts of Avater, had no immediate influence
on the motion and life of the cells, whilst a solution
of iodine so weak as not to render starcli anywhere
visible, acts at once as an active poison. Cohn observed
that when he had starch granules together with motile
zoospores on the object glass, and added a very dilute
solution of iodine, the motile cells, by tlieir death, shew
themselves to be mucb more sensitive reagcnts with
respect to iodine, even than starch. Rapid evapora-
tion of the water in which the motile forms of Proto -
coccus may be contained, kills them at once, but a more
gradual, such as takes place in deep glasses, causes

552

THE NATURAL HISTORY OF

tliem merely to pass into tlie still form, in wliich they
retain tlieir vitality for years.

Colm observed very frequently tliat the contact of
metal witli the water in which the Protococcus-cells were,
was destructive to tlieir life.

In the still form, the phenomena attendant upon the
cessation of life, are somewhat different from those in
the motile cells. In certain circumstances, the con-
tents, particularly in the red zoospores, dissolve, from
the periphery, into innumerable minute droplets. Or a
peculiar dissolntion of the coloured contents takes place,
in such a way tliat they lose tlieir colour, also from without
to witliin, so tliat «at last the cell appears dense and
opaque, but altogcther colourless, and is deprived of all
vitality. (Fig. 43.)

The paper tlien concludes witli some general consider-
ations.

I. The question arises, whether the Prolococcus is
necessarily to be regarded in all its stages of development
as a Plant ; or whether it sliould not ratlier be referred
to the Animal kingdom.

To any one who reads the writings of the rnost distin-
guished observers on tliis subject, it appears almost in-
comprehensible, tliat any doubt could exist whether any
organism, when sufficiently investigated, sliould be an
animal or a plant. For all, nearly without an exception,
agree in tliis, tliat an animal and a plant are essentially
and typically of distinct structure, and tliat tliis essential
diversity must also be expressed in the most minute
and lowest organisms ; and tliat, therefore, there can be
no question of any real analogy between an animal and
a plant, to say nothing of a relationship or a transition
from one into the other.

It appears, however, to Cohn, tliat the question of
animal or plant has beeil stated too generally, and
requires to be defined witli greater precision. As the
question is generally put, it would include the inquiry

PROTOCOCCUS PLUVIALIS.

553

as to whether the Protococcus pluvialis were allied to the
Lion or to the Oak. All our common notions of the
two kingdoms being derived from such higher organisms
as those, and not from those of the invisible world.

But the Protococcus is as far from the Lion as it is from
the Oak; there are observable in it, properties which would
appear to find their analogies only in certain animals or
certain plants, viz., among the Infusoria or the Algse.

Of the latter, again, the more highly organised, multi-
cellular forms must be excluded, these belonging mani-
festly to the Yegetable Kingdom. A Fucus, for instance,
is incontestably differently constructed from a Protococcus
cell. It is only the so-called unicellular Algae of Nägeli,
the Palmeliese and Diatomacese, about whose proper
position there can exist any possible doubt.

In the same way, of Infusoria, next to the Rotifera, all
those among the Polygastrica of Ehr. must be excluded,
which have distinctly a mouth and anus, as well as an
intestinal canal, or at least an cesophagus. With respect
to these, also, no doubt can arise as to their proper
position in the scale of animated nature.

Besides these, however, there are Infusoria, having
neither intestine nor anus, which do not take in any solid
nutriment, and in which the existence of a mouth is not
demonstrable by direct observation, and can only be sur-
mised from analogy. These constitute the division of the
Anentera, Ehr., Asto?na, v. Siebold. With respect to
these, it may certainly be reasonably questioned, whether
an organism should be more properly referred to this
division of the Infusoria, or to the Algm just mentioned.
It cannot but be doubtful whether a given creature is to
be regarded as belonging to the Monadina, Cryptomo-
nadina, Volvocina , Astasiece, Bacillarice, Amoebce, Arcel-
lincc, &c., or whether it should not be referred to the
Cryplococcacca, Protococcacea, Palmellca, Desmidiece,
and Biatomacece. It may even be questioned, whether
some of these natural fainilies be not more nearly related
with some families in the othcr kingdom, than with their

554

THE NATURAL H1ST0RY OF

neighbours in the kingdom to which they tbemselves
belong, or wliether even certain divisions from both natural
kingdoms might not properly be associated. It is only
witli tliis limitation tliat the question, as here considered,
must be understood, — wliether Protococcus pluvialis isto
be regarded as animal or plant j or, since of the above-
mentioned genera of Infusoria some only present any
similarity witli it, wliether it is to be considered as an
animal belonging to the Monadina , Cryptomonadina,
Volvocina, or Puglence, or wliether it should not be
referred, as an Alga, to the family of the Palmellese.

Although Elotow, after much consideration, comes to
the conclusion tliat Protococcus pluvicdis must be regarded
as a plant, the reasons upon which he is induced to come
to tliis conclusion do not appearto be well cliosen. They
are, — 1. its capability of revival after liaving been dried
for montlis and years ; 2. the viability of separate por-
tions of its substance ; 3. the occurrence of gennnation
which, moreover, in the proper sense of the Word, is rnore
than doubtful. All of which circuinstances may be
obscrved occasionally in the Animal Kingdom.

By Morren, on the otlicr hand, tliis organism, under
the nanie of Discenccci purpur ca, is arranged among the
Infusoria in the family of the Cryptomonadina, Ehr., and
has assigned to it a place close to Trachelomonas volvocina,
Morren, (non Ehr.) Eocke also conceives tliat the reasons
above assigned by Elotow for the vegetable nature of
Protococcus , are the rather calculated to prove its animal
nature.

According to Ehrenberg, for an organism to be charac-
terised distinctly as an Infusorium, it is requisite tliat it
should possess a complete Organisation analogous in all
respects to that of the higher animals ; on the otlier hand,
however, Dujardin, Siebold, Kölliker, &c., contest tliis,
considering spontaneity and contractility alone, as indis-
pensable criteria.

Now to consider Protococcus pluvialis in both these
points of view.

PROTOCOCCTJS PLUVIALIS.

555

First, as regards Ehrenberg’ s doctrine. The Organisa-
tion of Protococcus may very plausibly be referred to that
of the anenterate Infusoria, as understood by that ob-
server ; in this case the enveloping cell might perhaps be
explained as the shield ; the primordial cell as the proper
body of the animal ; the chlorophyll-vesicles, colonrless
grannles, and cytoblasts, as the testes ; the red and green
globules as ova; the frecpiently existing red pigment spots
as eyes ; the vibratile cilia as a proboscis ; the hyaline
spot as mouth ; and the vacuoles as stomachs. At all
events the organs which Ehrenberg has figured and
described as of such nature in Tracltelomonas , Volvocc,
Euglena , Chlamidomonas, Closterium, Euastrum, &c.,
present such appearances that, although they are in reality
organised in an essentially different way, they cannot be
optically distinguished from what they are represented
to be.

On the other side, these bodies correspond in all
respects with the organisms which are found either
absolutely in indubitable plants, or in the spores of such
plants.

Whence it is apparent that the proof of an animal
Organisation offered by Ehrenberg, does not suffice in
doubtful cases incontestably to prove the animal nature
of a doubtful creature when alive, because formations are
presented even in plants which cannot be directly shown
to be distinct by optical or cliemical means, but only
indirectly, with the aid of analogy.

If, on the contrary, that view of the structure of the
Infusoria be the more correct, which regards them only
as simple contractile cells, and all the above elementary
parts as parallel, not with animal but with vegetable
organisms, we arrive at more comprehensive conclusions.

One of the characteristics of Protococcus is this, that it
affords analogies, at different periods of its growth, not
with one only, but with many genera hitherto considered
distinct. Thus the motile, or “ swarming,” form agrees
with the genus Pandorina, Ehr., or more closely still

556

TEE NATURAL HISTORY OF

witli Chlamidomonas, from which, indeed, it. is scarcely to
be distinguisked. But the latter, according to Cohn, has
not yet been observed in the “ still” condition.

But Pandorina and Chlamidomonas lmve long enjoyed
only a very doubtful character as animals; Kützing having
arranged the former among the Palmellacese, as Botryo-
cystis morum ; and Siebold the latter among the Algae,
in spite of the only certain character adraitted by him as
distinctive of an animal nature, viz., the contractility of
the body.

Protococcus pluvialis, however, presen ts the most
striking analogies with genera in which this property is
exhibited in the highest degree, the genera Euglena and
Astasia, which, according to our present knowledge,
must be rcgardcd as indubitable animals, their claim to
be so considered having even never yet been called in
question by any careful observer.*

Among the points in which the closest resemblance
exists between Protococcus and Euglena , inay be enu-
merated the following : —

1. The red matter in the latter presents precisely the
same characters, and, like tliat of Protococcus, is coloured
blue by iodine, and contains corpuscles not to be distin-
guished from the Chlorophyll -vesicles.

2. The colourless cxtremities of Euglena manifestly
correspond with the colourless elongation of protoplasma
at the two ends of the Protococcus cell ; the beak also of
Euglena , with its single cilium, precisely corresponds
with the biciliated extremity of Protococcus.

3. The eye-spot of Euglena appears to be chemically
analogous with the red pigment spot in certain stages of
the zoospores of Protococcus ; it is equally coloured blue
by iodine.

If to the above it be added that Euglena , at least
according to Dujardin, Siebold, and Kölliker, equally
presents the characters of a simple closed cell, it will be

* This is now, by no mcans, the casc. — [Ed.]

PROTOCOCCUS PLUVIALIS.

557

apparent that the motile form of Euglena is constituted
on the same type as the primordial cell of the motile form
of Protococcus.

The author then details some observations on the
development of Euglena viridis.

Euglena is not always motile ; at certain times it passes
into a state of rest. To this end, it assnmes a globular
form, developes more opaque, denser contents, and forms
around itself, a rigid, colourless membrane ; in this state
it cannot be distinguished from the still form of Proto-
coccus pluvialis, and as in that plant, the cells are often
united into floating expansions. In this form, and par-
ticularly when aggregated into these expansions, it has
already been occasionally placed among the Algse ; Micro-
cgstis Noltii, Kg. appears to be the still form of Euglena
sanguinea , and M. olivacea , Kg. is probably to be referred
to Euglena viridis.

This stage, however, of the so-called process of
becoming encysted, is not, as commonly supposed,
connected with the decease of the organism, but within
the membrane, Segmentation goes on ; the coloured,
enclosed globular body subdividing exactly as in Proto-
coccus into two, four, eight, sixteen, thirty-two, or more
portions. These isolated, primordial cells, as they may be
called, become free, by rupture of the rigid wall enclosing
them ; and either resemble their parent, or when much
sm aller, are very dissimilar to it, assuming more the ap-
pearance of green, eyeless Monads.

On the other hand, the motile form of Euglena , also,
just like the motile zoospore of Protococcus may sub-
divide into two, or it may be into more, also motile
secondary individuals. Whence it is manifest that the
development of Euglena viridis , proceeds on precisely
the same type as that of Protococcus pluvialis.

With respcct to the motion of the Protococcus cells ;
it is to be noticed that Ehrenberg, and with him all
later observers, agree that animal motion is voluntary,
arising from internal psychical causes, that it is conscious

558

THE NATURAL HISTORY OF

and directed to some object ; whilst that of plants vvould
appear to depend upon external pliysical causes or Stimuli ;
that it is not voluntary, nor directed to any object,
but automatic (vide Ehr., Abh. d. Berl. Ak. 1830).
Cohn, however, from numerous observations expressly
directed to this point, is disposed to call in question, the
existence of this essential distinction between the motions
of the Infusoria, and that of the vegetable zoospore.

Leaving out of the question the more highly organised
Infusoria furnished with the manifest mouth and ceso-
phagus, the motion of a large part of the Anenter a , Ehr.
Astoma, Siebold, is not essentially different from that
of the zoospores of certain Algae.

Towards the end of the paper, Colin observes, that in
the course of its preparation he had only been able upon
optical and physiological grounds, to rcnder it probable,
that the rigid cell membrane of the still form and the
tcnder envcloping cell of the motile zoospores, consist
of the same non-nitrogenous material, of whicli the
rigid membrane of all plant-cells is composed — viz. :
cellulose ; he had, however, since succeeded, by Chemical
means, in placing this fact beyond doubt. If a drop of
water containing some still and motile zoospores, be
brought in contact simultan eously with a very dilute
watery solution of iodine, and moderately diluted sul-
pliuric acid, the “ enveloping” cells of the motile and
the cell-membrane of the still form, immediately assume
a beautiful blue colour (Eig. 47). In performing this
experiment, it is necessary to employ neither a too con-
centrated, nor a too much diluted sulphuric acid.

The author concludes by some general observations on
the subject of the “Alternation of Generations,” exhibited
in such instances as Protococcus pluvialis, and on the im-
portance of the history of its development, with relation to
a systematic arrangement of the Algse. Most of our spe-
cies and genera , are based merely upon differences in size,
form, and thickness of the cell-wall, and the colour, con-
sistence, and intimate Organisation of the contents. But

PROTOCOCCUS PLUVIALIS.

559

the history of the development of Protococcus pluvialis,
shews how very uncertain such characters are. It cannot
be doubted, moreover, that the great diversities exhibited
in the above respects, at different stages of its growth, by
Protococcus pluvialis, exist also in other Algse, if they
were duly sought after, and that researches in other
species, from the same points of view as those embraced
in the present memoir, would probably reduce very
materially the large number of genera and species of
Algae.

Thus we see that a single species, owing to its nu-
merous modes of propagation, can pass through a number
of very various forms of development, which have been
either erroneously arranged as distinct genera, or at
least as remaining stationary in those genera, although,
in fact, only transitionary stages. Thus the still Proto-
coccus cell, (Fig. 2,) corresponds to the common Proto-
coccus coccoma. Kg. When the border becomes gelatinous,
it resembles P. pulclier (Fig. 70); and the small cells,
P. minor. The encysted motile zoospore is the genus
Gyges granuhm among the Infusoria, resembling also, on
the other side, P. turgides, Kg. and perhaps, P. versa-
tilis, Braun. The zoospores divided into tvvo (Figs. 23, 30),
must be regarded as a form of Gyges bipcirtitus, or of
P. dimüliatus. In the quaclripartite zoospores, with the
secondary cells arranged in one plane, we have a Gonium
(Fig. 37). That with eight segments (Fig. 38,) corre-
sponds to Pandorina Morum, and that with sixteen, to
Botryocystis Volvox (Fig. 44). When the zoospore is
divided into thirty-two segments, it is a TJvella or Syn-
crypta (Fig. 40). When tliis form enters the “still”
stage, it may be regarded as a form analogous to
Microhaloa protogenita ; this Algal genus is probably,
speaking generally, only the product of the Uvella division
in the Euglence or other green forms. The naked
zoospores (Fig. 32), finally, would represent the form
of a Monad, or of an Astasia ; the caudate variety, ap-
proaches that of a Bodo.

560

PROTOCOCCUS PLUVIALIS.

A critical and comparative consideration of the fore-
going facts would therefore appear to render untenable
almost all the principles which modern systematists
have hitherto adopted as the basis for the constmction
of their Natural Kingdoms, Families, Genera, and
Species.

But it must not hence be concluded, that the result
of these investigations implies the existence of a state of
coinplete anarchy in the domain of microscopic organisms ;
or that any one form among them, may assume any
other form indifferently; that, in fact, there are no real
species in the invisible world. Such is by no means
the case.

Critical enquiries such as the present, have for their
result — like the spear of Telephus — the healing of the
wound tliey infiict. It is manifestly better, — although at
the expense of erroneous notions, long admitted as in-
fallible — to substitute, by the aid of a complete and
continuous history of development, a much more defined,
because natural idea, of Genus and Species, for that
hitherto set up, in artificial, but, at the same time, un-
natural Systems.

RaxL&Went. Cbromo fmp

DESCRIPTION OF FIGURES.

Fig.

1. — A small “still” cell of Protococcus pluvialis,

revived after desiccation. The contents gru-
mous, almost filling the cell-membrane.

2. — A very large cell, in which the red, finely granulär

contents, fill up the membrane, and have in the
centre a clearer space. (cytoblast P)

3. — A green cell with chlorophyll-vesicles, containing

an excentric, reddish, lighter-coloured vesicle
(nucleus ?) surrounded by an opaque red ring.

4. — A cell which had been dry for six years, under-

going Segmentation after its revival ; one half is
green and granulär ; the other red, presenting an
oil-like substance.

5. — A cell which has assumed an elliptical figure pre-

paratory to its dividing.

6. — Division further advanced.

7. — Completed division. The secondary cells appear

to have a cellulose coat, and are surrounded by
the mother-cell, which has become gelatinous.

8. — Division into four.

9. — The same, still surrounded by the parent-cell.

10. — Commencement of division; a green, small cell,

with a red Zone at the border, and red central
substance, gs well as a lighter coloured nucleus.

11. — A “still” cell, containing, within a distant, dense,

colourless coat, a coloured globule also surrounded
with a membrane.

12. — A large naked zoospore, green, with red central

substance, and a colourless spot at the anterior
end, with two vibratile cilia, originating, either in
the division of an encvsted zoospore or from a
“ still” cell.

13. — An irregular-shaped, quadrangular, flat, Euglenci-

like zoospore, with chlorophyll-vesicles, colourless
anterior end, and two cilia.

36

562

DES0R1PTI0N OP FIGURES.

Fig.

14. - — A green cell with red central substance, on the

point of assuming the motile form.

15. — An encysted zoospore, with filaments of protö-

plasm, (P. setiger , Flotow), a distant “ envelop-
ing cell,” two cilia, clilorophyll-vesicles, &c.

16. — An encysted zoospore, with distant “enveloping

cell,” green, gelatinous, primordial cell ; red,
granulär, disseminated central substance, and a
colourless point, (P. papillatus, Flot.)

17. — A very small, globular, encysted zoospore, (P. ro-

tundatus, Flotow.)

18. — An encysted zoospore, pointed at botli ends, alto-

gctlier green, (P. rostellaius, Flot.)

19. — Commencing division of the primordial cell into two.

20. — A young pyriform primordial cell, around which

the “enveloping cell” is just beginning to show
itself distinct from the primordial cell.

21. — An older cell, with colourless vacuoles.

22. — Commencing division into two ; the wholly green,

primordial cell, closely surrounded by the en-
veloping cell, shows a constriction in the middle.

23. — Commencing division into two ; each secondary

primordial cell has developed an enveloping cell
around itself, whilst still within theparent cell.

24. — Commencing division into four.

25. — An unusual and incomplete division into live;

four pointed, encysted zoospores, not completely
parted aftcr the resorption of the common “ en-
veloping cell,” remaining connected by pro-
cesses arising from the point where the cilia are
placed ; a smaller portion has become organized
into a naked primordial cell, also connected with
the others. (Yide fig. 39.)

26. — Only half of the primordial cell consists of the

green globular substance ; the otlier half is a
colourless granulär protoplasin, enclosing in the
centre a red substance resembling a nucleus.

27. — An encysted zoospore in the commencement of

DESCRIPTION OF FIGURES.

563

Fig.

deliquescence. The primordial cell is resolved
into green and red granules, forms clear vacuoles,
and is on the point of filling np the enveloping cell.

28. — An encysted zoospore wbich bas deliquesced; tbe

primordial cell bas entirely filled tbe “ enveloping
cell,” and becorne resolved into green and red
granules.

29. — An encysted zoospore, whicli bas passed into tbe

“ still” condition ; tbe spberical, vvbolly green,
primordial cell, bas acquired a closely investing
cellulose coat, wbilst tbe “enveloping cell,” bas
becorne resolved into a mucoid substance, on
wbich tbe cilia are no longer visible.

30. — Division of a “ still” cell into two elliptical secondary

cells, wbich present a nucleus in tbe centre, and
remain enclosed by tbe parent cell, becorne gela-
tinous. (Yide fig. 7.)

31. — Division of a “still” cell into eight : the parent cell

is resolved into a gelatinous substance, and
encloses eight small, cylindrical, red zoospores.

32. — Two of these zoospores after their escape.

33. — Yellow-green “ still” cell, with gelatinous envelope.

34. — An encysted zoospore, the primordial cell of whicli

is on the point of division into two. Tbe remote,
enveloping cell snpports tbe two cilia, whose
presence is only indicated by tbe current they
produce.

35. — An elliptical encysted zoospore, tbe primordial cell

of wliich is already divided into two secondary
cells. The vibratile cilia and transparent pro-
jections upon wbich they are placed, are visible
within the parent-cell.

36. — One of the secondary cells after its liberation.

37. — Division of an encysted cell into four j the globular,

green, granulär, secondary cells, almost tili the
parent-cell ; arranged something like the cells in
Goniurn pectorale.

38. — Division of an encysted zoospore into eight globular.

564

DESCRIPTION OE EIGURES.

Fig.

secondary, primordial cells, which almost fill the
parent-cell. Their disposition resembles tliat of

Botryocystis morum. Kg.

39. — Incomplete division of an encysted zoospore into

four, also encysted secondary cells, which remain
connected in the centre after the removal of their
common enveloping cell. This seems to repre-
sent a further development of tliat given in
figure 25.

40. — Division of an encysted cell into thirty-two minute,

spherical, entirely green, primordial cells, which
completely fill their delicate parent-cell. This
arrangement corresponds to the genus Spharas-
trum tesserale , Kg., or to Uvella virescens, Ehr.,
or to Syncrypta volvox, Ehr.

41. — Zoospores from the last-described form escaped

from the parent-cell. One of thcm ( a ) shows
the formation of a membrane around it.

42. — An encysted zoospore witli a spherical primordial

cell, the green, non-granular contents of which,
are retracted to one side, in a crescentic form,
wliilst a colonrless vesicle occupies the other half.
This modification appears to depend upon a
deficient supply of water.

43. — A red cell, which, by desiccatiön, has become

colourless, showing grumous contents witli oil-
globules.

44. — A large red “ still” cell, the contents of which are

divided into numerous (64 ?) segments.

45. — A red encysted cell.

46. — A red “still” cell, originating in the transition of

the cell represented in fig. 45 into the “still”
condition.

47. — An encysted zoospore, treated witli iodine and

sulphuric acid.

* * All the figures are magnified under a power of

500 linear.

INDEX OF GENERA OF MICROSCOP1C ALG/E
TREATED IN THIS VOLUME.

Achnantkes, 407.

Acknantkidium, 407.

Actiniscus, 487.

Actinoeyclus, 477.

Actinoptychus, 478.

Ampkipentas, 481.

Amphipleura, 421.

Amphiprora, 422.

Ampkitetras, 480.

Amphora, 423.

Anabaina, 146.

Aphanochmte, 184, 209, 230, 233,
250.

Apiocystis, 133, 209.

Artkrosipkon, 178.

Ascidium, 125, 127, 185, 186, 200,
209, 267, 286.

Bacillaria, 399.

Bambusina, 291, 295.
Batrachospermum, 150, 151,
Berkeleya, 426.

Biddulpkia, 484, 512.

Botrydium, 128, 193, 220, 274.
Botryocystis, 159, 209, 559.
Bryopsis, 129, 140, 166, 268.
Bulbockaete, 141, 1 51, 156, 157, 183,
201, 209, 303.

Campylodiscus, 394.

Caulerpa, 129, 174.

Ceratoneis, 421.

Chffitomorpha, 185, 186, 268
Chsetopkora, 139, 151, 156, 183,
208, 224, 231, 253.

Chantransia, 143, 151, 183, 231.
Ckaracium, 125, 485, 209, 229,230,
250.

Cklamidococcus, 138, 158, 174, 184,
196, 205, 211, 216, 224, 229, 238,
250, 258, 498, 518.
Cklamidomonas, 214, 215, 216.

Cklorococcum, 213, 260, 508.
Ckroococcacese, 131, 174, 190, 197.
Ckroococcus, 131, 182, 230.
Cladopkora, 150, 174, 185, 199,
220, 235, 236, 239, 240, 253,
268.

Climacospkenia, 465, 512.
Closterium, 133, 140, 175, 204, 281,
289, 291, 292, 259, 497.
Coccoueis, 405.

Cocconema, 286, 410.

Coleocksete, 141, 151, 183, 208, 253,
270, 298.

Couferva, 184, 205, 209.
Coscinodiscus, 476.

Cosmarium v. Euastrum.

Cyclo tella, 385.

Cylindrocystis, 287.
Cylindrospermum, 146.

Cymalonema, 141.

Cymbella, 409.

Cymbosira, 408.

Cystococcus, 125, 185.

Cystoseira, 248.

Denticula, 379.

Desmidium, 294.

Desmidiaceas, 133, 139, 174, 203,
247, 283, 290, 497.

Diadesmis, 424.

Diatoma, 382.

Diatomacese, 132, 139, 190, 247,
283, 345.

Dictyocha, 488.

Dictyosphffirium, 132, 209, 238.
Didymoprium, 291, 295.

Docidium, 180, 291.

Dorypkora, 406.

Draparnaldia, 139, 151, 156, 183,
208, 224, 231.

Dysphinctium, 203.

566

INDEX.

Echinaria, 400.

Encyonema, 411.

Endococcus, 213, 268.
Enteromorpha, 184, 250.

Epithemia, 374.

Euactis, 147, 178.

Euastrum, 133, 181, 224, 294, 295,
300.

Eumeridion, 378.

Eunotia, 286, 375.

Exococcus, 254.

Eragillaria, 381.

Erustulia, 425.

Gallionclla, 389.

Glscocapsa, 131, 132, 182, 190, 499.
GJajococcus, 159, 209.

Glacocystis, 131, 161, 182, 190.
Gltcodictyon, 498.

Goinphonema, 238, 286, 412.
Gongros ira, 183, 209.

Goniiun, 159.

Grallatoria, 402.

Grammatoncma, 381.
Grammatophora, 473.

Gyges, 499, 559.

Hmmatococcus v. 498, 508, 518, also
v. Chlamidomouas.

ITaplosiphon, 150.

Hassallia, 150.

Hirnantidiura, 286, 376.
Homoeocladia, 426.

Hormidium, 131, 208.

Hyalosira, 466.

Ilyalotheca, 291, 295.

Hydrodictyon, 125, 127, 137, 156,
171, 185, 186, 190, 197, 199,
208, 219, 220, 261.

Istlimia, 482.

Isthmosira, 291, 295.

Lemania, 154.

Leptomitus lacteus, 270.
Licmophora, 464.

Lithodesmium, 480.

Lysigonium, 389.

Mast,ichonema, 147, 187.
Masticliothrix, 147.

Melosira, 139, 299, 389.

Meridion, 3 77.

Mesocarpus, 135, 288, 289, 369.
Mesogena, 488.

Micromega, 437.

Microhaloa, 559.

Mounema, 430.

Mougeotia, 288.

Navicula, 413.

Nostoc, 145, 155.

Odontella, 4S3.

Odontidiura, 380.

CEdogonium, 141, 148, 150, 156,

157, 161,162,163, 164, 170,175,
183, 196, 201, 212, 224, 22 7,

231, 247, 281, 300, 301, 302.
Ophiocytiura, 260.

Oscillaria, 132, 197.

Palmellacece, 131, 174, 190, 213,

499.

Palmoglaea, 133, 135, 202, 285.
Pandorina, 159, 209, 212, 224, 499,
559.

Pediastrum, 125, 161, 184, 200,
909 9^0 9r.C»

Penium, 181, 190, 203, 289, 292.
Pleurococcus, 131, 182, 213, 230,
258.

Pleurodcsmiuin, 495.

Pododiscus, 387.

Podosira, 388.

Podosphenia, 462.

Prasiola, 131.

Protococcus, 125, 127, 209, 212,
213, 258, 499, 50 7, 518.
Pyxidicula, 387.

Eapbidoglaea, 426.
llhabdonema, 467.

Ehipidiphbra, 463.

Ebynconema, 289.

Eimaria, 402.

Eivularia, 146, 147, 148, 178.

Saprolegnia,185, 188, 252, 268, 269,
298.

Sarcococca, 36.

Scaphularia, 399.

Scenedesmus, 250.

Scliizocldamys, 181.

Schizonema, 139, 286, 428.

INDEX.

567

Scbizosiphon, 147, 178.

Sciadium, 187, 209, 260.

Scytonema, 146, 147, 178, 186.
Sirogoniuni, 288.

Spermosira, 146.

Sphaeroplea, 164, 271, 281.
Sphserozyga, 146.

Sphenella, 411.

Sphenosira, 413.

Spirogyra, 135, 175, 180, 196, 201,
224, 239, 241, 244, 281, 289, 300.
Staurocarpus, 134, 281, 296.
Stauroceras, 287.

Stauroneis, 422.

Staurospermum, v. Staurocarpus.
Stigeoclonium, 139, 156, 163, 183,
208, 224, 360, 498.

Striatella, 466.

Surirella, 396.

Syncyclia, 410.

Syuedra, 399.

Tabellaria, 470.

Tabularia, 402.

Terpsinoe, 472, 512.

Tessella, 466.

Tetmemorus, 291.
i Tetrachococcus, 258.

Tetracyclus, 469.

Tetraspora, 132, 209.

Tolpotnrix, 147, 186.

Triceratium, 487.

Tripodiscus, 482.

Ulothrix, 125, 148, 156, 159, 175,
184, 200, 208, 223, 250, 360,
498.

Ulnaria, 400.

Ulva, 125, 184, 250.

Urococcus, 178, 230.

Vaucberia, 128, 140, 157, 163, 174,
183, 209, 212, 221, 251, 296.
Yolvociuese, 158, 159, 208, 216,
250.

Zygnema, 175, 288.

Zygneroacese, 133, 135, 164, 174,
180, 287, 359.

Zygogonium, 177, 288.

Zygoceras, 486.

C. AN I) J. AUl.AllI*. PKINTK/t». HA lll H U LO M KW 0LO8K.

REPORT

OF THE

COUNCIL OF THE RAY SOCIETY,

Read at the Tenth Anniversar y Meeting, held at ITull, Sept. I2th, 1853 ;

W. SPENCE, Esa., F.R.S., in the Chair.

The Ray Society was established in the year 1844, for the purpose of Publishing
and supplying to its Members, original works, translations, and reprints of works,
that were not likely, on account of their expense, to be published in the transactions
of existing societies, or to be undertaken by publishers, in consequence of the im-
probability of their meeting with a remunerative sale. The Council of the Ray
Society feel it necessary to remind the Members of this fact, as it will explain, on
the one hand, why their works cannot be of ahiglily populär character, and on
the other hand, why they feel that they have a Claim on the Support of all those
who are anxious to promote the study of Natural History Science. As to how
the Society has fulfilled its mission, they would appeal to the twenty-two volumes
which have already been issued to the Members. Many of them are Standard works
on the subjects to which they have been devoted, and all have contributed to
advance a knowledge of the principles and facts involved in the study of the Sciences
of Zoology and Botany.

Since the last Anniversary Meeting of the Society, which was held at Belfast, in
September, 1852, the following works have been distributed to the Members:

1. Yol. I of Mr. C. Darwin’s Monograph of the family of Cirripedes; including

the Sea-acorns ( Balani ).

2. Vol. III of the Bibliographia Zoologiae et Geologi®, by Professor Agassiz ;

edited by II. E. Strickland, Esq., F.R.S.

The Council had hoped that they should have been able to have announced at the
present Meeting the distribution of two other works, but circumstances ovcr which
they have had no control have prevented their being able to do so. One of these
works, the sixth and last part of Messrs. Alder and Ilancock’s worlc on the Nudi-
branchiate Mollusca, has been deferred on account of the wish of the authors to use

2

REPORT OP THE RAY SOCIETY.

all the materials in their possession up to the present time, and thus to render the
work as complete as possible.

The publication of the second volume of Mr. Darwin’s work on the Cirripedes has
also been delayed, in order to enahle the author to include in it his researches upon
collections of animals belonging to tliis familv which have been recently tnade.

Instead of a mixed volume of papers by foreign authors on subjects in Zoology
and Botany, the Council have resolved, at the request of many of their hotanical
Members, to publish a translation of I)r. A. Braun’s work on the Rejuvenescence of
Plants. This work will he edited by Mr. Henfrey; and Meneghini’s paper on the
Animal Nature of the Biatomaceca , and an abstract of Cohn’s paper on the Natural
History of Protococcus pluvialis, will be added. This book is nearly completed, and
will be speedily issued, with the sixth part of Messrs. Alder and Hancock’s Mono-
graph. The publication of Hoffmeister’s work on the Reproduction of the
Cryptogamia, which the Council had tliought of translating, they are glad to state
has been undertakcn by Mr. Highley, and they hope will shortly appear, so as to be
accessible to the English Student.

For the year 1854, the Council propose, if no unforeseen circumstance arise, to
publish the fourth volume of the Bibliography of Zoology and Geology. They have
also grqat pleasurc in announcing tbat they have received the plates of Professor
Alhnan’s work on the British Fresh-water Zoophytes, and that this work, with
thirteen coloured plates, in imperial 4to, will be one of the publications for 1854.

The Council would especially call the attention of the Members to their financial
condition. Last year they had to report that £657 were due on that and the
past years. They have now to report that £707 are due. Of this sum :

£336 18s. is due for 1853,

£144 13s. „ „ 1852,

£91 6s. „ „ 1851,

£84 12s. „ „ 1850,

£50 8s. „ 1847-8-9.

Düring the past year the number of Members who have witbdrawn or died amounts
to 45, and 8 Members have been added ; so that there are now 709 on the list.

The Council would again urge that the only limits they have to their labours are
the funds derived from their subscriptions, and that just in proportion as these are
increased, are they enabled to publish a larger amount of matter to present to the
Members for their subscription of one guinea per annum.

The Council appointed, last year, J. S. Bowerbank, Esq., Treasurer; and Dr. G.
Johnston, of Berwick-on-Tweed, and Dr. Lankester, London, Secretaries.

REPORT OF THE RAY SOCIETY.

3

Abstract of Treasurer' s Account fi'om June, 1852, to May,

1853.

llKCEIVRD. £ S.

d.

EXPENDED.

£ s. d.

Casli in hantl at last audit . . 86 11

6

Bookbiuding

29 15 0

By snbscriptions .... 642 17

0

Eugraving, printing, &c.

76 15 10

Printing letter-press

. 226 0 3

Editing ....

54 6 0

Collector ....

24 10 7

Books . . .

2 13 6

Secretary ....

. 125 0 0

Advertising ....

8 3 3

Local Secretaries’ Expenses .

9 10 0

Postage, Stationery, &c.

9 6 11

566 1 4

Cash in hand .

. 63 7 2

£629 8

6

£629 8 6

Auditors :

George Shadbolt.
James Tennant.

Moved by Professor Balfour ; seconded by R. M'Andrews, Esq. :

That the Report now read be adopted, and printed for circulation amongst the
Members of the Society.

Moved by J. Hogg, Esq. ; seconded by R, J. Bell, Esq. :

That the thanks of this Meeting be given to the President, Council, Treasurer
Secretaries, Local Secretaries, and Auditors, for their Services during the past
year.

Moved by Dr. Lee; seconded by A. Strickland, Esq. :

That the following Gentlemen be requested to act as a Council for the following
year.

Professor D. T. Ansted m.a. f.r.s.
f.l.s.

Charles C. Babington, Esq., m.a.
f.r.s. f.l.s.

Robert Ball, Esq., ll.d. m.r.i.a.,

Sec. r.z.s.i.

Professor Bell, Sec. r.s., f.l.s.

J. S. Bowerbank, Esq., f.r.s. f.l.s.

George Büsk, Esq., f.r.s. f.l.s.

W. B. Carpf.nter, m.d. f.r.s.

Professor Daubeny, m.d. f.r.s.

Sir P. de M. G. Egerton, Bart., m.f.
f.r.s.

Professor Edward Forbes, f.r.s.
f.l.s.

ProfessorGoodsir,m.d. f.r.s. l. and e.

A. Henfrey, Esq., f.r.s. f.l.s.

Sir W. Jardine, Bart., f.r.s.e. l.s.
Rev. Leonard Jenyns, m.a. f.l.s.

G. Johnston, m.d. ll.d. f.r.c.s.e.

E. Lankester, m.d. ll.d. f.r.s. F.Lis.
Professor Owen, d.c.l. f.r.s. f.l.s.
Robert Patterson, Esq., Pres. Nat.
Hist. Soc. Bel.

Professor John Phillips, f.r.s.
Prideaux J. Selby, Esq., f.l.s.

W. Spence, Esq., f.r.s. f.l.s.

IIugh E. Strickland, Esq. m.a. f.r.s.

F.G.S.

G. Waterhouse, Esq., f.z.s.

W. Yarrell, Esq., f.l.s.

*

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