



Produced by Bryan Ness, Carol Brown, and the Online
Distributed Proofreading Team at http://www.pgdp.net (This
file was produced from images generously made available
by The Internet Archive/Canadian Libraries)






                              THE WORKS

                                  OF

                      FRANCIS MAITLAND BALFOUR.

                               VOL. I.

                          Memorial Edition.




                              Cambridge:

                 PRINTED BY C. J. CLAY, M.A. AND SON,
                       AT THE UNIVERSITY PRESS.




           [Illustration: Sketch of Francis Maitland Balfour]




                          Memorial Edition.

                              THE WORKS

                                  OF

                      FRANCIS MAITLAND BALFOUR,

                         M.A., LL.D., F.R.S.,

                      FELLOW OF TRINITY COLLEGE,
        AND PROFESSOR OF ANIMAL MORPHOLOGY IN THE UNIVERSITY OF
                              CAMBRIDGE.




                              EDITED BY

                          M. FOSTER, F.R.S.,
        PROFESSOR OF PHYSIOLOGY IN THE UNIVERSITY OF CAMBRIDGE;

                                 AND

                        ADAM SEDGWICK, M.A.,
           FELLOW AND LECTURER OF TRINITY COLLEGE, CAMBRIDGE.




                                VOL. I.

                           SEPARATE MEMOIRS.




                               London:
                           MACMILLAN AND CO.
                                 1885




                [_The Right of Translation is reserved._]




                                PREFACE.


Upon the death of Francis Maitland Balfour, a desire very naturally arose
among his friends and admirers to provide some memorial of him. And, at a
public meeting held at Cambridge in October 1882, the Vice-Chancellor
presiding, and many distinguished men of science being present, it was
decided to establish a 'Balfour Fund' the proceeds of which should be
applied: firstly to maintain a studentship, the holder of which should
devote himself to original research in Biology, especially in Animal
Morphology, and secondly, 'by occasional grants of money, to further in
other ways original research in the same subject'. The sum of L8446 was
subsequently raised; this was, under certain conditions, entrusted to and
accepted by the University of Cambridge; and the first 'Balfour student'
was appointed in October 1883.

The publication of Balfour's works in a collected form was not proposed as
an object on which part of the fund should be expended, since his family
had expressed their wish to take upon themselves the charge of arranging
for a memorial edition of their brother's scientific writings. That
edition, with no more delay than circumstances have rendered necessary, is
now laid before the public. It comprises four volumes.

The first volume contains, in chronological order, all Balfour's scattered
original papers, including those published by him in conjunction with his
pupils, as well as the Monograph on the Elasmobranch Fishes. The last
memoir in the volume, that on the Anatomy and Development of Peripatus
Capensis, was published after his death, from his notes and drawings, with
additions by Prof. Moseley and Mr Adam Sedgwick, who prepared the
manuscript for publication. To the volume is prefixed an introductory
biographical notice.

The second and third volumes are the two volumes of the Comparative
Embryology reprinted from the original edition without alteration, save the
correction of obvious misprints and omissions.

The fourth volume contains the plates illustrating the memoirs contained in
Vol. 1. We believe that we are consulting the convenience of readers in
adopting this plan, rather than in distributing the plates among the
memoirs to which they belong. To assist the reader the explanations of
these plates have been given twice: at the end of the memoir to which they
belong (in the case of the Monograph on Elasmobranch Fishes at the end of
each separate chapter), and in the volume of plates.

All the figures of these plates had to be redrawn on the stone, and our
best thanks are due to the Cambridge Scientific Instrument Company for the
pains which they have taken in executing this work. We are also indebted to
the Committee of Publication of the Zoological Society for the gift of
electrotypes of the woodcuts illustrating memoir no. XX. of Vol. 1.

Several photographs of Balfour, taken at different times of his life, the
last shortly before his death, are in the possession of his relatives and
friends; but these, in the opinion of many, leave much to be desired.

There is also a portrait of him in oils painted since his death by Mr John
Collier, A.R.A., and Herr Hildebrand of Florence has executed a posthumous
bust in bronze[1]. The portrait which forms the frontispiece of Vol. 1. has
been drawn on stone by Mr E. Wilson of the Cambridge Scientific Instrument
Company, after the latest photograph. Should it fail, in the eyes of those
who knew Balfour well, to have reproduced with complete success his
features and expression, we would venture to ask them to bear in mind the
acknowledged difficulties of posthumous portraiture.

  Footnote 1: In possession of the family. Copies also exist in
  the Library of Trinity College, and in the Morphological
  Laboratory, at Cambridge.




                        TABLE OF CONTENTS.

                                                                 PAGE

         PREFACE                                                    i

         INTRODUCTION                                               1


                              1872

      I. On some points in the Geology of the East Lothian
         Coast. By G. W. and F. M. BALFOUR                         25


                              1873

     II. The development and growth of the layers of the
         blastoderm. With Plate 1                                  29

    III. On the disappearance of the Primitive Groove in the
         Embryo Chick. With Plate 1                                41

     IV. The development of the blood-vessels of the Chick.
         With Plate 2                                              47


                              1874

      V. A preliminary account of the development of the
         Elasmobranch Fishes. With Plates 3 and 4                  60


                              1875

     VI. A comparison of the early stages in the development
         of Vertebrates. With Plate 5                             112

    VII. On the origin and history of the urinogenital organs
         of Vertebrates                                           135

   VIII. On the development of the spinal nerves in Elasmobranch
         Fishes. With Plates 22 and 23                            168


                              1876

     IX. On the spinal nerves of Amphioxus                        197


                             1876-78

      X. A Monograph on the development of Elasmobranch
         Fishes. With Plates 6-21                                 203


                              1878

     XI. On the phenomena accompanying the maturation and
         impregnation of the ovum                                 521

    XII. On the structure and development of the vertebrate
         ovary. With Plates 24, 25, 26                            549


                              1879

   XIII. On the existence of a Head-kidney in the Embryo Chick,
         and on certain points in the development of the
         Muellerian duct. By F. M. BALFOUR and A. SEDGWICK.
         With Plates 27 and 28                                    618

    XIV. On the early development of the Lacertilia, together
         with some observations on the nature and relations of
         the primitive Streak. With Plate 29                      644

     XV. On certain points in the Anatomy of Peripatus Capensis   657

    XVI. On the morphology and systematic position of the
         Spongida                                                 661


                              1880

   XVII. Notes on the development of the Araneina. With Plates
         30, 31, 32                                               668

  XVIII. On the spinal nerves of Amphioxus                        696

    XIX. Address to the Department of Anatomy and Physiology
         of the British Association for the Advancement of
         Science                                                  698


                              1881

     XX. On the development of the skeleton of the paired fins of
         Elasmobranchii, considered in relation to its bearings
         on the nature of the limbs of the Vertebrata. With
         Plate 33                                                 714

    XXI. On the evolution of the Placenta, and on the possibility
         of employing the characters of the Placenta in the
         classification of the Mammalia                           734


                              1882

   XXII. On the structure and development of Lepidosteus. By
         F. M. BALFOUR and W. N. PARKER. With Plates
         34-42                                                    738

  XXIII. On the nature of the organ in Adult Teleosteans and
         Ganoids which is usually regarded as the Head-kidney
         or Pronephros                                            848

   XXIV. A renewed study of the germinal layers of the Chick. By
         F. M. BALFOUR and F. DEIGHTON. With Plates
         43, 44, 45                                               854


                         POSTHUMOUS, 1883

    XXV. The Anatomy and Development of Peripatus Capensis.
         Edited by H. N. MOSELEY and A. SEDGWICK. With
         Plates 46-53                                             871




Francis Maitland Balfour, the sixth child and third son of James Maitland
Balfour of Whittinghame, East Lothian, and Lady Blanche, daughter of the
second Marquis of Salisbury, was born at Edinburgh, during a temporary stay
of his parents there, on the 10th November, 1851. He can hardly be said to
have known his father, who died of consumption in 1856, at the early age of
thirty-six, and who spent the greater part of the last two years of his
life at Madeira, separated from the younger children who remained at home.
He fancied at one time that he had inherited his father's constitution; and
this idea seems to have spurred him on to achieve early what he had to do.
But, though there was a period soon after he went to College, during which
he seemed delicate, and the state of his health caused considerable anxiety
to his friends, he eventually became fairly robust, and that in spite of
labours which greatly taxed his strength.

The early years of his life were spent chiefly at Whittinghame under the
loving care of his mother. She made it a point to attempt to cultivate in
all her children some taste for natural science, especially for natural
history, and in this she was greatly helped by the boys' tutor, Mr J. W.
Kitto. They were encouraged to make collections and to form a museum, and
the fossils found in the gravel spread in front of the house served as the
nucleus of a geological series. Frank soon became greatly interested in
these things, and indeed they may be said to have formed the beginnings of
his scientific career. At all events there was thus awakened in him a love
for geology, which science continued to be his favorite study all through
his boyhood, and interested him to the last. He was most assiduous in
searching for fossils in the gravel and elsewhere, and so great was his
love for his collections that while as yet quite a little boy the most
delightful birthday present he could think of was a box with trays and
divisions to hold his fossils and specimens. His mother, thinking that his
fondness for fossils was a passing fancy and that he might soon regret the
purchase of the box, purposely delayed the present. But he remained
constant to his wish and in time received his box. He must at this time
have been about seven or eight years old. In the children's museum, which
has been preserved, there are specimens labelled with his childish
round-hand, such as a piece of stone with the label "marks of some shels;"
and his sister Alice, who was at that time his chief companion, remembers
discussing with him one day after the nursery dinner, when he was about
nine years old, whether it were better to be a geologist or a naturalist,
he deciding for the former on the ground that it was better to do one thing
thoroughly than to attempt many branches of science and do them
imperfectly.

Besides fossils, he collected not only butterflies, as do most boys at some
time or other, but also birds; and he with his sister Alice, being
instructed in the art of preparing and preserving skins, succeeded in
making a very considerable collection. He thus acquired before long not
only a very large but a very exact knowledge of British birds.

In the more ordinary work of the school-room he was somewhat backward. This
may have been partly due to the great difficulty he had in learning to
write, for he was not only left-handed but, in his early years, singularly
inapt in acquiring particular muscular movements, learning to dance being a
great trouble to him. Probably however the chief reason was that he failed
to find any interest in the ordinary school studies. He fancied that the
family thought him stupid, but this does not appear to have been the case.

In character he was at this time quick tempered, sometimes even violent,
and the energy which he shewed in after life even thus early manifested
itself as perseverance, which, when he was crossed, often took on the form
of obstinacy, causing at times no little trouble to his nurses and tutors.
But he was at the same time warm-hearted and affectionate; full of strong
impulses, he disliked heartily and loved much, and in his affections was
wonderfully unselfish, wholly forgetting himself in his thought for others,
and ready to do things which he disliked to please those whom he loved.
Though, as we have said, somewhat clumsy, he was nevertheless active and
courageous; in learning to ride he shewed no signs of fear, and boldly put
his pony to every jump which was practicable.

In 1861 he was sent to the Rev. C. G. Chittenden's preparatory school at
Hoddesden in Hertfordshire, and here the qualities which had been already
visible at home became still more obvious. He found difficulty not only in
writing but also in spelling, and in the ordinary school-work he took but
little interest and made but little progress.

In 1865 he was moved to Harrow and placed in the house of the Rev. F.
Rendall. Here, as at Hoddesden, he did not show any great ability in the
ordinary school studies, though as he grew older his progress became more
marked. But happily he found at Harrow an opportunity for cultivating that
love of scientific studies which was yearly growing stronger in him. Under
the care of one of the Masters, Mr G. Griffith, the boys at Harrow were
even then taught the elements of natural science. The lessons were at that
time, so to speak, extra-academical, carried on out of school hours;
nevertheless, many of the boys worked at them with diligence and even
enthusiasm, and among these Balfour became conspicuous, not only by his
zeal but by his ability. Griffith was soon able to recognize the power of
his new pupil, and thus early began to see that the pale, earnest, somewhat
clumsy-handed lad, though he gave no promise of being a scholar in the
narrower sense of the word, had in him the makings of a man of science.
Griffith chiefly confined his teaching to elementary physics and chemistry
with some little geology, but he also encouraged natural history studies
and began the formation of a museum of comparative anatomy. Balfour soon
began to be very zealous in dissecting animals, and was especially
delighted when the Rev. A. C. Eaton, the well-known entomologist, on a
visit to Harrow, initiated Griffith's pupils in the art of dissecting under
water. The dissection of a caterpillar in this way was probably an epoch in
Balfour's life. Up to that time his rough examination of such bodies had
revealed to him nothing more than what in school-boy language he spoke of
as "squash;" but when under Eaton's deft hands the intricate organs of the
larval Arthropod floated out under water and displayed themselves as a
labyrinth of threads and sheets of silvery whiteness a new world of
observation opened itself up to Balfour, and we may probably date from this
the beginning of his exact morphological knowledge.

While thus learning the art of observing, he was at the same time
developing his power of thinking. He was by nature fond of argument, and
defended with earnestness any opinions which he had been led to adopt. He
was very active in the Harrow Scientific Society, reading papers, taking
part in the discussions, and exhibiting specimens. He gained in 1867 a
prize for an essay on coal, and when, in 1868, Mr Leaf offered a prize (a
microscope) "for the best account of some locality visited by the writer
during the Easter Holidays," two essays sent in, one by Balfour, the other
by his close friend, Mr Arthur Evans, since well known for his researches
in Illyria, were found to be of such unusual merit that Prof. Huxley was
specially requested to adjudicate between them. He judged them to be of
equal merit, and a prize was given to each. The subject of Balfour's essay
was "The Geology and Natural History of East Lothian." When biological
subjects were discussed at the Scientific Society, Balfour appears to have
spoken as a most uncompromising opponent of the views of Mr Charles Darwin,
little thinking that in after life his chief work would be to develop and
illustrate the doctrine of evolution.

The years at Harrow passed quickly away, Balfour making fair, but perhaps
not more than fair, progress in the ordinary school learning. In due course
however he reached the upper sixth form, and in his last year, became a
monitor. At the same time his exact scientific knowledge was rapidly
increasing. Geology still continued to be his favorite study, and in this
he made no mean progress. During his last years at Harrow he and his
brother Gerald worked out together some views concerning the geology of
their native county. These views they ultimately embodied in a paper, which
was published in their joint names in the _Geological Magazine_ for 1872,
under the title of "Some Points in the Geology of the East Lothian Coast,"
and which was in itself a work of considerable promise. Geology however was
beginning to find a rival in natural history. Much of his holiday time was
now spent in dredging for marine animals along the coast off Dunbar. Each
specimen thus obtained was carefully determined and exact records were kept
of the various 'finds,' so that the dredgings (which were zealously
continued after he had left Harrow and gone to Cambridge) really
constituted a serious study of the fauna of this part of the coast. They
also enabled him to make a not inconsiderable collection of shells, in the
arrangement of which he was assisted by his sister Evelyn, of crustacea and
of other animals.

Both to the masters and to his schoolfellows he became known as a boy of
great force of character. Among the latter his scrupulous and unwavering
conscientiousness made him less popular perhaps than might have been
expected from his bright kindly manner and his unselfish warmheartedness.
In the incidents of school life a too strict conscience is often an
inconvenience, and the sternness and energy with which Balfour denounced
acts of meanness and falsehood were thought by some to be unnecessarily
great. He thus came to be feared rather than liked by many, and
comparatively few grew to be sufficiently intimate with him to appreciate
the warmth of his affections and the charm of his playful moments.

At the Easter of 1870 he passed the entrance examination at Trinity
College, Cambridge, and entered into residence in the following October.
His college tutor was Mr J. Prior, but he was from the first assisted and
guided in his studies by his friend, Mr Marlborough Pryor, an old Harrow
boy, who in the same October had been, on account of his distinction in
Natural Science, elected a Fellow of the College, in accordance with
certain new regulations which then came into action for the first time, and
which provided that every three years one of the College Fellowships should
be awarded for excellence in some branch or branches of Natural Science, as
distinguished from mathematics, pure or mixed. During the whole of that
year and part of the next Mr Marlborough Pryor remained in residence, and
his influence in wisely directing Balfour's studies had a most beneficial
effect on the latter's progress.

During his first term Balfour was occupied in preparation for the Previous
Examination; and this he successfully passed at Christmas. After that he
devoted himself entirely to Natural Science, attending lectures on several
branches. During the Lent term he was a very diligent hearer of the
lectures on Physiology which I was then giving as Trinity Praelector, having
been appointed to that post in the same October that Balfour came into
residence. At this time he was not very strong, and I remember very well
noticing among my scanty audience, a pale retiring student, whose mind
seemed at times divided between a desire to hear the lecture and a feeling
that his frequent coughing was growing an annoyance to myself and the
class. This delicate-looking student, I soon learnt, was named Balfour, and
when the Rev. Coutts Trotter, Mr Pryor and myself came to examine the
candidates for the Natural Science Scholarships which were awarded at
Easter, we had no difficulty in giving the first place to him. In point of
knowledge, and especially in the thoughtfulness and exactitude displayed in
his papers and work, he was very clearly ahead of his competitors.

During the succeeding Easter term and the following winter he appears to
have studied physics, chemistry, geology and comparative anatomy, both
under Mr Marlborough Pryor and by means of lectures. He also continued to
attend my lectures, but though I gradually got to know him more and more we
did not become intimate until the Lent term of 1872. He had been very much
interested in some lectures on embryology which I had given, and, since
Marlborough Pryor had left or was about to leave Cambridge, he soon began
to consult me a good deal about his studies. He commenced practical
histological and embryological work under me, and I remember very vividly
that one day when we were making a little excursion in search of nests and
eggs of the stickleback in order that he might study the embryology of
fishes, he definitely asked my opinion as to whether he might take up a
scientific career with a fair chance of success. I had by this time formed
a very high opinion of his abilities, and learning then for the first time
that he had an income independent of his own exertions, my answer was very
decidedly a positive one. Soon after, feeling more and more impressed with
his power and increasingly satisfied both with his progress in biological
studies and his sound general knowledge of other sciences, anxious also, it
may be, at the same time that as much original inquiry as possible should
be carried on at Cambridge in my department, I either suggested to him or
acquiesced in his own suggestion that he should at once set to work on some
distinct research; and as far as I remember the task which I first proposed
to him was an investigation of the layers of the blastoderm in the chick.
It must have been about the same time that I proposed to him to join me in
preparing for publication a small work on Embryology, the materials for
this I had ready to hand in a rough form as lectures which I had previously
given. To this proposal he enthusiastically assented, and while the lighter
task of writing what was to be written fell to me, he undertook to work
over as far as was possible the many undetermined points and unsatisfactory
statements across which we were continually coming.

During his two years at College his health had improved; though still
hardly robust and always in danger of overworking himself, he obviously
grew stronger. He rejoiced exceedingly in his work, never tiring of it, and
was also making his worth felt among his fellow students, and especially
perhaps among those of his own college whose studies did not lie in the
same direction as his own. At this time he must have been altogether happy,
but a sorrow now came upon him. His mother, to whom he was passionately
attached, and to whose judicious care in his early days not only the right
development of his strong character but even his scientific leanings were
due, had for some time past been failing in health, though her condition
caused no immediate alarm. In May 1872, however, she died quite suddenly
from unsuspected heart disease. Her loss was a great blow to him, and for
some time afterward I feared his health would give way; but he bore his
grief quietly and manfully and threw himself with even increased vigour
into his work.

During the academic session of 1872-3, he continued steadily at work at his
investigations, and soon began to make rapid progress. At the beginning he
had complained to me about what he considered his natural clumsiness, and
expressed a fear that he should never be able to make satisfactory
microscopic sections; as to his being able to make drawings of his
dissections and microscopical preparations, he looked upon that at first as
wholly impossible. I need hardly say that in time he acquired great skill
in the details of microscopical _technique_, and that his drawings, if
wanting in so-called artistic finish, were always singularly true and
instructive. While thus struggling with the details which I could teach
him, he soon began to manifest qualities which no teacher could give him. I
remember calling his attention to Dursy's paper on the Primitive Streak,
and suggesting that he should work the matter over, since if such a
structure really existed, it must, most probably, have great morphological
significance. I am free to confess that I myself rather doubted the matter,
and a weaker student might have been influenced by my preconceptions.
Balfour, however, thus early had the power of seeing what existed and of
refusing to see what did not exist. He was soon able to convince me that
Dursy's streak was a reality, and the complete working out of its
significance occupied his thoughts to the end of his days.

The results of these early studies were made known in three papers which
appeared in the _Quarterly Journal of Microscopical Science_ for