HICKS ON MR ARCHER S PAPER ON ALQM tain

							         HICKS, ON MR. ARCHER'S PAPER ON ALQM.                 253

tain forms requires much knowledge of the substance em-
ployed, and some patience, as there are many interfering
causes to combat. Of these the weather is by no means an
inactive one, as it is frequently found almost impossible to
obtain the above-named feathery crystals when the place in
which crystallization take3 place is cold and damp. When
the temperature is low, and yet too dry, santonine will fre-
quently assume the form of a uniform semi-transparent
mass after fusion, showing no crystalline shape; yet the
same portion will crystallize beautifully when again fused,
interfering means being employed. This is also the case
with many other salts.
   I myself was long under the impression that it was merely
the thickness of the salt which caused the various forma-
tions ; but OH. closer inspection found that, though thickness
certainly did influence the forms, I did not find it difficult to
procure the same class of crystals with either thick or thin
coverings of the fused salt by recalling the before-mentioned
facts.




    REMARKS on Mr.      ARCHER'S PAPER on ALGJE.          By
        J. BRAXTON HICKS, M.D., F.R.S., F.L.S. &c.
   IT was with much pleasure I read Mr. Archer's paper in
your Journal of April, 1864, read before the Natural History
Society of Dublin, inasmuch as it opens up a question of
much interest in many points of view, but more particularly
bearing deeply on the validity of the classification of the
unicellular forms of vegetable life. And as he in many
places refers to my observations on these growths set forth,
in former numbers of your Journal, I may, perhaps, be
allowed to occupy a further space on the same subject.
   The title and the whole of this paper, coming as it does
from so able and indefatigable an observer, proves more than
any remarks I could have made the very unsatisfactory
condition in which our. knowledge remains, and also the
great difficulty (may I say impossibility?) of fixing the
separate species or genus to which the majority of the
Palmellacese belong.
   When, after all Mr. Archer's careful and earnest researches
on the subject, the title of this paper is called an "Endeavour
to Identify the Palmoglcea Macrococca of Kiitzing " with a
plant which he (Mr. Archer) thinks is meant, but which,
254       HICKS, ON MR. ARCHER'S PAPER ON ALGJE.

with another new species, he thinks is referable rather to
another genus, it would seem almost a hopeless task to assist
in the work. If Kiitzing, Naegele, De Bary, and other
equally celebrated algologists, are unable to decide the position
of the various Palmellacese, and are further unable to agre«
upon what are the essential characters by which to settle these
points, what can be better proof of the intrinsic difficulty oi
the whole question? If by one observer the envelope of
mucoid matter be taken as a specific or even generic sign—.
if the mode of segmentation be taken by another as of specific
or generic value—if the size of the cell, or the position of the
nucleus, or the mode of diffusion of the endochrome within
the cell, be sufficient in the eyes of another to separate genera—
if, as Mr. Archer contends, the oval shape is another impor-
tant distinction—it seems to me no wonder that the difficulty,
acknowledged by all, has arisen.
   If, again, inability after careful research to determine what
is meant by Kiitzing's character of the genus Palmogloea be
admitted by Mr. Archer and Braun; and if Mr. Archer thinks
that this genus is separable into five types, two of which he
thinks do not at all belong to it; when, in fact, no one
algologist can tell distinctly what is a Palmogloea, so as to be
understood by any other algologist; then, I must confess, it
seems difficult to understand how Mr. Archer can find suffi-
cient ground to state that a Macrococca is not the state
figured by me as similar to Palmogloea amongst the forms
produced by the lichen-gonidia. Mr. Archer is by no means
certain of what I mean by Palmoglvea Brebissonii, for he
questions whether it be the same as that which Kiitzing makes
identical with Palmella cylindrospora, which Ralf considers
identical with Penium Brebissonii, and which Mr. Archer
places with Cylindrocystis; and which, as far as can be
ascertained, Mr. Thwaites calls Coccochloris Brebissonii,
although Mr. Archer thinks he means the Trichodictyon
rupestro. The exact characters of this form, it will thus be
 seen, are by no means settled by any one of these observers.
 The exceeding confusion prevailing in this species extends
 similarly throughout the whole group, and leaves it in such
 a state of uncertainty that it would be well if the whole of
 these forms were to undergo complete remodelling.
    But the question first of all arises, how is a single cell to be
 distinguished from another single ceil? "What reliable charac-
 ters are to be fixed upon which can be considered as of generic
 value ? When we consider through what various forms those
 cells pass whose life-history has been carefully watched, as
 for example, Protococcus pluvialis, the very species with
         HICKS, ON MR. ARCttER's PAPER ON ALGJE.              255

which Mr. Archer illustrated his paper, how are we to tell to
what genus any single cell belongs ? how can we tell whether
it be a fixed form, a separate entity, or merely a transitional
form of some other growth ? When, again, we find, as I have
shown in thi3 Journal, and in the' Transactions of the Linnean
Society,' that cells quite similar in all respects are produced
during the segmentation of the gonidia of the lichens, mosses,
Lycopodia, Prasiola, &c, in what manner, may it be asked,
are we to tell to what group it belongs, and how can we say
that it is certainly a separate Palmellaceous plant ?
     It is clear that the whole question must be gone over com-
pletely, not with the distinct intent of dividing each of these
forms into genera and species, but for the purpose of tracing
their history as far as practicable, in order to find out through
what various forms they can pass, and more especially to in-
quire how many homomorphous forms can spring from
 different structures.
     The whole case resolves itself into this heavy task, a subject
 which will require the combined efforts of many observers,
 and one which I am fully aware will hold out little attraction
 for those whose love of distinctness and definiteness draws
 them rather to analysis than to synthesis. It is one to which,
 if Mr. Archer will apply his patient and careful habits of
 observation, he will find it repay his pains far more amply
 than endeavouring to unravel the confusion of authors. These
 views I have already expressed in the papers above quoted,
 and I may repeat that I consider that, till the life-history is
 traced out, it is impossible to tell whether the growth before
 one be a distinct form or not.
     The principal point which must be first determined is,
 what are the characters to the differences of which we can
  assign a generic or specific value ? Is size to be taken as a
  guide ? The size of any cell depends on many circumstances,
  as, for instance, upon the rate of segmentation compared with
  individual growth. This is well seen by observing continu-
  ously the process of the gonidia of lichens or mosses. The
  size depends also upon the temperature and other external
  circumstances affecting the activity of its vital powers. There
  is no doubt the subdivision of a cell may extend to almost
  an invisible point, and in that state it may so remain for an
  indefinite period; and that it may begin at any time to grow,
  till it reach the size of the parent, and probably to a still
  larger, provided, however, segmentation does not commence.
      Does the position of the nucleus help us ? How, then, can
  those states be classified in which there is no nucleus ? I
  think few will consider that the position of the nucleus, of a
256      HICKS, ON MR. ARCHER'S PAPER ON ALGiE.

starch-granule, or of a vescicle, can be considered of any
assistance whatever.
   Can the disposition of the chlorophyll? How, then, are we
to arrange those forms where the whole contents are homo-
geneous? How are we to place those whose contents are
without any definite arrangement ? It seems that but little
value can be placed upon this in the majority of cases, to
which any one who has observed the various arrangements of
the contents in the same plant I think will agree. It is
true that in some there are peculiar dispositions, as in
Zygonema and its allies, and, when present, no doubt is of
certain value; but even in this case the contents may become
homogeneous, as in conjugating; and then, supposing sub-
division to take place, the contents of the resulting cells
would become more or less homogeneous, and thus the spiral
character lost.
   Can the mode of subdivision assist us? Before this can
be answered we must find out in how many modes, and in
what varieties of forms, this process can take place. Here
is a vast field. Let us therefore inquire of nature in every
stage of the life of a cell—in its active spring growth,
during and after its period of conjugating, in its zoospore
stage, and in the forms the zoospore may ultimately assume,
in the autumn growth, and in the various stages the winter-
resting spore may pass through before it reach again the
parent form. Let nature be fully inquired of here, and I have
no doubt an ample harvest will be the reward. Can the
form of the cell be of any help ? If it is found that the sub-
divisions of a generally round form assume an oval, at any
stage, and then revert to the round shape, what value can
we put upon the form ? That this can be constantly observed
is palpable to any one who will watch the segmenting gonidia
of lichens and other plants. I need only refer again to the
plate illustrating Mr. Archer's paper. The varying forms
of the divisions show that their form changes very strangely.
This is observable in almost every Converfa, and the Des-
midise are good examples. Supposing Mr. Archer had carried
his observations as Colin has done in Protococcus pltwialis,
it is highly probable that as diverse forms would have been
found.
   Upon what, then, are we to fix ? No other answer seems
practicable but that which I have already indicated, namely,
upon the gradations assumed during its whole life-history.
If it be asked, how can this be attained ? it must be honestly
answered, with much labour and careful observation; better
trace one form out well than endeavour to attain an appa-
         HICKS, ON ME. ARCHER'S PAPER ON ALGiE.              257

rently large result by that which cannot be relied upon,
although it may have the attraction of being definite.
   In this particular subject especially algologists have
generally endeavoured to restrict nature into the narrowest
compass \ they have made orders, genera, and species innu-
merable, out of the simple physiological process of cell-growth,
and have used even the ordinary variations of subdivision as
a means to classification.
   Had a tithe of the labour bestowed upon the classification
of the Palmellacese been devoted to their life-history, some
progress by this time would have been made in the herculean
task.
   One point, I think, will tend to shake our confidence in the
certainty of the separate existence of these forms, to which I
have also formerly alluded ; it is this, that when we consider
the multitudes of mosses and lichens to be found everywhere
capable of producing gonidia, and from them Palmellaceous
forms to an indefinite extent, and varying probably according
to the species, what absolute proof can we possibly have of
the separate existence of any similar form unless we know its
history ? I am sorry to give utterance to so much scepticism,
and to cause such perturbations in the minds of those devoted
to the subject; but I am certain the sooner misgivings
occur on the validity of the mode hitherto adopted, the sooner
we shall attain a more satisfactory knowledge of what I am
certain will prove to be a wide page in the book of nature.
   Mr. Archer has rather misunderstood me in concluding
that I consider all species of British Palmogloea can arise
from the lichen Cladonia. I mean that all forms similar to
those hitherto described can certainly arise from it, but I
do not mean to affirm that no other forms of vegetable life
do not also give origin to similar cells. I have little doubt
but that a more extended knowledge of the matter will show
that segmenting gonidia of other orders will also produce
similar forms, as I have already shown in the mosses. At
the same time I do not mean to say there are no such forms
as distinct Palmellacese. I admit it is possible; but 1 ask,
how are we to be sure the specimen before us is so ? For
this reason I cannot agree with thinking with Mr. Archer
that I have been hasty or comprehensive in my generaliza-
tions.
   What value in classifying can be attributed to that peculiar
action called conjugation ? 1 think we can hardly judge at
present. That it is but a process of vegetative, as distinguished
from sexual action, is clear; but whether it is to be considered
as a sign belonging only to the Confervoid group-section, it is
258              E. RAY LANKESTER, ON THE

impossible to say; at any rate, for ought we know to the
contrary, it may be also formed during the growth of the
gonidium of lichens, and it would seem rash at our present
state of information to confine it within any limits. Further
observations are wanting before we can consider it peculiar
to the Confervse.
   The same remark may be applied to the zoospores, the
formation of which is also asexual process. We have evidence
which shows that the formation of zoospores extends over
a wider range than had formerly been believed. There,
again, is a fine field here for observation. It is very possible
that some of the Volvocinaese may have an origin in some
other form of life, especially since Cohn has shown forms of
zoospores of Protococcus pluvialis, united in such a manner
as to partake of many of the features of that" ti'ibe. No
finer field than the one I have above pointed out is open for the
patient observer, who will carefully trace, and as carefully
portray, every step of the form in which he is interested.




              The ANATOMY of the EARTHWORM.
                   By E. RAY LANKESTER.

                            PART I.

   BEING desirous of publishing a notice of certain new
points of structure which I have detected in the earthworm,
I thought that it might be well to accompany it with a
description of the general anatomy of that Annelid, espe-
cially since the later and more accurate observations on this
subject have been published as papers in foreign journals,
and are scattered about in various French, Belgian, and
German periodicals. The appearance too, of a paper in the
'Philosophical Transactions' for 1858, by Dr. Williams, in
which the anatomy of the reproductive organs of Lumbricus
is treated of, has been a further inducement to me to publish
my observations on this point. The separate researches
of two Continental naturalists, M. Jules d'Udekem and Dr.
Ewald Hering, had placed our knowledge of the generative
system of the earthworm in a so far satisfactory state that
little more remained to be done than to explain a few minor
discrepancies between the results arrived at by these authors.
Dr. Williams, however, having failed to observe that which is