sympathetic nerve。
〃'4th。 Partial closure of the eyelids in animals born of parents in
which that state of the eyelids had been caused either by the
section of the cervical sympathetic nerve or the removal of the
superior cervical ganglion。
〃'5th。 Exophthalmia in animals born of parents in which an injury
to the restiform body had produced that protrusion of the eyeball。
This interesting fact I have witnessed a good many times； and I have
seen the transmission of the morbid state of the eye continue
through four generations。 In these animals modified by heredity；
the two eyes generally protruded； although in the parents usually
only one showed exophthalmia； the lesion having been made in most
cases only on one of the corpora restiformia。
〃'6th。 Haematoma and dry gangrene of the ears in animals born of
parents in which these ear…alterations had been caused by an injury
to the restiform body near the nib of the calamus。
〃'7th。 Absence of two toes out of the three of the hind leg； and
sometimes of the three； in animals whose parents had eaten up their
hind…leg toes which had become anaesthetic from a section of the
sciatic nerve alone； or of that nerve and also of the crural。
Sometimes； instead of complete absence of the toes； only a part of
one or two or three was missing in the young； although in the parent
not only the toes but the whole foot was absent （partly eaten off；
partly destroyed by inflammation； ulceration； or gangrene）。
〃'8th。 Appearance of various morbid states of the skin and hair of
the neck and face in animals born of parents having had similar
alterations in the same parts； as effects of an injury to the
sciatic nerve。'
〃It should be especially observed that Brown…Sequard has bred during
thirty years many thousand guinea…pigs from animals which had not
been operated upon； and not one of these manifested the epileptic
tendency。 Nor has he ever seen a guinea…pig born without toes；
which was not the offspring of parents which had gnawed off their
own toes owing to the sciatic nerve having been divided。 Of this
latter fact thirteen instances were carefully recorded； and a
greater number were seen； yet Brown…Sequard speaks of such cases as
one of the rarer forms of inheritance。 It is a still more
interesting fact； 'that the sciatic nerve in the congenitally
toeless animal has inherited the power of passing through all the
different morbid states which have occurred in one of its parents
from the time of the division till after its reunion with the
peripheric end。 It is not； therefore； simply the power of
performing an action which is inherited； but the power of performing
a whole series of actions； in a certain order。'
〃In most of the cases of inheritance recorded by Brown…Sequard only
one of the two parents had been operated upon and was affected。 He
concludes by expressing his belief that 'what is transmitted is the
morbid state of the nervous system；' due to the operation performed
on the parents。〃
Mr。 Darwin proceeds to give other instances of inherited effects of
mutilations：…
〃With the horse there seems hardly a doubt that exostoses on the
legs； caused by too much travelling on hard roads； are inherited。
Blumenbach records the case of a man who had his little finger on
the right hand almost cut off； and which in consequence grew
crooked； and his sons had the same finger on the same hand similarly
crooked。 A soldier； fifteen years before his marriage； lost his
left eye from purulent ophthalmia； and his two sons were
microphthalmic on the same side。〃
The late Professor Rolleston； whose competence as an observer no one
is likely to dispute； gave Mr。 Darwin two cases as having fallen
under his own notice； one of a man whose knee had been severely
wounded； and whose child was born with the same spot marked or
scarred； and the other of one who was severely cut upon the cheek；
and whose child was born scarred in the same place。 Mr。 Darwin's
conclusion was that 〃the effects of injuries； especially when
followed by disease； or perhaps exclusively when thus followed； are
occasionally inherited。〃
Let us now see what Professor Weismann has to say against this。 He
writes：…
〃The only cases worthy of discussion are the well…known experiments
upon guinea…pigs conducted by the French physiologist； Brown…
Sequard。 But the explanation of his results is； in my opinion； open
to discussion。 In these cases we have to do with the apparent
transmission of artificially produced malformations 。 。 。 All these
effects were said to be transmitted to descendants as far as the
fifth or sixth generation。
〃But we must inquire whether these cases are really due to heredity；
and not to simple infection。 In the case of epilepsy； at any rate；
it is easy to imagine that the passage of some specific organism
through the reproductive cells may take place； as in the case of
syphilis。 We are； however； entirely ignorant of the nature of the
former disease。 This suggested explanation may not perhaps apply to
the other cases； but we must remember that animals which have been
subjected to such severe operations upon the nervous system have
sustained a great shock； and if they are capable of breeding； it is
only probable that they will produce weak descendants； and such as
are easily affected by disease。 Such a result does not； however；
explain why the offspring should suffer from the same disease as
that which was artificially induced in the parents。 But this does
not appear to have been by any means invariably the case。 Brown…
Sequard himself says： 'The changes in the eye of the offspring were
of a very variable nature； and were only occasionally exactly
similar to those observed in the parents。'
〃There is no doubt； however； that these experiments demand careful
consideration； but before they can claim scientific recognition；
they must be subjected to rigid criticism as to the precautions
taken； the nature and number of the control experiments； &c。
〃Up to the present time such necessary conditions have not been
sufficiently observed。 The recent experiments themselves are only
described in short preliminary notices； which； as regards their
accuracy； the possibility of mistake； the precautions taken； and the
exact succession of individuals affected； afford no data on which a
scientific opinion can be founded〃 （pp。 81； 82）。
The line Professor Weismann takes； therefore； is to discredit the
facts； yet on a later page we find that the experiments have since
been repeated by Obersteiner； 〃who has described them in a very
exact and unprejudiced manner；〃 and that 〃the fact〃（I imagine that
Professor Weismann intends 〃the facts〃）〃cannot be doubted。〃
On a still later page； however； we read：…
〃If； for instance； it could be shown that artificial mutilation
spontaneously reappears in the offspring with sufficient frequency
to exclude all possibilities of chance； then such proof ＇i。e。； that
acquired characters can be transmitted＇ would be forthcoming。 The
transmission of mutilations has been frequently asserted； and has
been even recently again brought forward； but all the supposed
instances have broken down when carefully examined〃 （p。 390）。
Here； then； we are told that proof of the occasional transmission of
mutilations would be sufficient to establish the fact； but on p。 267
we find that no single fact is known which really proves that
acquired characters can be transmitted； 〃FOR THE ASCERTAINED FACTS
WHICH SEEM TO POINT TO THE TRANSMISSION OF ARTIFICIALLY PRODUCED
DISEASES CANNOT BE CONSIDERED AS PROOF〃 ＇Italics mine。＇ Perhaps；
but it was mutilation in many cases that Professor Weismann
practically admitted to have been transmitted when he declared that
Obersteiner had verified Brown…Sequard's experiments。
That Professor Weismann recognises the vital importance to his own
theory of the question whether or no mutilations can be transmitted
under any circumstances； is evident from a passage on p。 425 of his
work； on which he says： 〃It can hardly be doubted that mutilations
are acquired characters； they do not arise from any tendency
contained in the germ； but are merely the reaction of the body under
certain external influences。 They are； as I have recently expressed
it； purely somatogenic charactersviz。； characters which emanate
from the body （soma） only； as opposed to the germ…cells； they are；
therefore； characters that do not arise from the germ itself。
〃If mutilations must necessarily be transmitted〃 ＇which no one that
I know of has maintained＇； 〃or even if they might occasionally be
transmitted〃 ＇which cannot； I imagine； be reasonably questioned＇； 〃a
powerful support would be given to the Lamarckian principle； and the
transmission of functional hypertrophy or atrophy would thus become
highly probable。〃
I have not found any further attempt in Professor Weismann's book to
deal with the evidence adduced by Mr。 Darwin to show that
mutilations； if followed by diseases； are sometimes inherited； and I
must leave it to the reader to determine how far Professor Weismann
has shown reason for rejecting Mr。 Darwin's conclusion。 I do not；
however； dwell upon these facts no