Beyond The Pleasure Principle
3746
If we do so, we may be astonished
to find how little agreement there is among biologists on the
subject of natural death and in fact that the whole concept of
death melts away under their hands. The fact that there is a fixed
average duration of life at least among the higher animals
naturally argues in favour of there being such a thing as death
from natural causes. But this impression is countered when we
consider that certain large animals and certain gigantic arboreal
growths reach a very advanced age and one which cannot at present
be computed. According to the large conception of Wilhelm Fliess,
all the phenomena of life exhibited by organisms - and also, no
doubt, their death - are linked with the completion of fixed
periods, which express the dependence of two kinds of living
substance (one male and the other female) upon the solar year. When
we see, however, how easily and how extensively the influence of
external forces is able to modify the date of the appearance of
vital phenomena (especially in the plant world) - to precipitate
them or hold them back - doubts must be cast upon the rigidity of
Fliess’s formulas or at least upon whether the laws laid down
by him are the sole determining factors.
The greatest interest attaches
from our point of view to the treatment given to the subject of the
duration of life and the death of organisms in the writings of
Weismann (1882, 1884, 1892, etc.) It was he who introduced the
division of living substance into mortal and immortal parts. The
mortal part is the body in the narrower sense - the
‘soma’ - which alone is subject to natural death. The
germ-cells, on the other hand, are potentially immortal, in so far
as they are able, under certain favourable conditions, to develop
into a new individual, or, in other words, to surround themselves
with a new soma. (Weismann, 1884.)
Beyond The Pleasure Principle
3747
What strikes us in this is the
unexpected analogy with our own view, which was arrived at along
such a different path. Weismann, regarding living substance
morphologically, sees in it one portion which is destined to die -
the soma, the body apart from the substance concerned with sex and
inheritance - and an immortal portion - the germ-plasm, which is
concerned with the survival of the species, with reproduction. We,
on the other hand, dealing not with the living substance but with
the forces operating in it, have been led to distinguish two kinds
of instincts: those which seek to lead what is living to death, and
others, the sexual instincts, which are perpetually attempting and
achieving a renewal of life. This sounds like a dynamic corollary
to Weismann’s morphological theory.
But the appearance of a
significant correspondence is dissipated as soon as we discover
Weismann’s views on the problem of death. For he only relates
the distinction between the mortal soma and the immortal germ-plasm
to
multicellular
organisms; in unicellular organisms the
individual and the reproductive cell are still one and the same
(Weismann, 1882, 38). Thus he considers that unicellular organisms
are potentially immortal, and that death only makes its appearance
with the multicellular metazoa. It is true that this death of the
higher organisms is a natural one, a death from internal causes;
but it is not founded on any primal characteristic of living
substance (Weismann, 1884, 84) and cannot be regarded as an
absolute necessity with its basis in the very nature of life
(Weismann, 1882, 33). Death is rather a matter of expediency, a
manifestation of adaptation to the external conditions of life;
for, when once the cells of the body have been divided into soma
and germ-plasm, an unlimited duration of individual life would
become a quite pointless luxury. When this differentiation had been
made in the multicellular organisms, death became possible and
expedient. Since then, the soma of the higher organisms has died at
fixed periods for internal reasons, while the protista have
remained immortal. It is not the case, on the other hand, that
reproduction was only introduced at the same time as death. On the
contrary, it is a primal characteristic of living matter, like
growth (from which it originated), and life has been continuous
from its first beginning upon earth. (Weismann, 1884, 84 f.)
Beyond The Pleasure Principle
3748
It will be seen at once that to
concede in this way that higher organisms have a natural death is
of very little help to us. For if death is a
late
acquisition of organisms, then there can be no question of there
having been death instincts from the very beginning of life on this
earth. Multicellular organisms may die for internal reasons, owing
to defective differentiation or to imperfections in their
metabolism, but the matter is of no interest from the point of view
of our problem. An account of the origin of death such as this is
moreover far less at variance with our habitual modes of thought
than the strange assumption of ‘death instincts’.
The discussion which followed
upon Weismann’s suggestions led, so far as I can see, to no
conclusive results in any direction.¹ Some writers returned to
the views of Goette (1883), who regarded death as a direct result
of reproduction. Hartmann (1906, 29) does not regard the appearance
of a ‘dead body’ - a dead portion of the living
substance - as the criterion of death, but defines death as
‘the termination of individual development’. In this
sense protozoa too are mortal; in their case death always coincides
with reproduction, but is to some extent obscured by it, since the
whole substance of the parent animal may be transmitted directly
into the young offspring.
Soon afterwards research was
directed to the experimental testing on unicellular organisms of
the alleged immortality of living substance. An American biologist,
Woodruff, experimenting with a ciliate infusorian, the
‘slipper-animalcule’, which reproduces by fission into
two individuals, persisted until the 3029th generation (at which
point he broke off the experiment), isolating one of the
part-products on each occasion and placing it in fresh water. This
remote descendent of the first slipper-animalcule was just as
lively as its ancestor and showed no signs of ageing or
degeneration. Thus, in so far as figures of this kind prove
anything, the immortality of the protista seemed to be
experimentally demonstrable.²
¹
Cf. Hartmann (1906), Lipschütz (1914)
and Doflein (1919).
²
For this and what follows see
Lipschütz (1914, 26 and 52 ff.).
Beyond The Pleasure Principle
3749
Other experimenters arrived at
different results. Maupas, Calkins and others, in contrast to
Woodruff, found that after a certain number of divisions these
infusoria become weaker, diminish in size, suffer the loss of some
part of their organization and eventually die, unless certain
recuperative measures are applied to them. If this is so, protozoa
would appear to die after a phase of senescence exactly like the
higher animals - thus completely contradicting Weismann’s
assertion that death is a late acquisition of living organisms.
From the aggregate of these
experiments two facts emerge which seem to offer us a firm
footing.
First: If two of the animalculae,
at the moment before they show signs of senescence, are able to
coalesce with each other, that is to ‘conjugate’ (soon
after which they once more separate), they are saved from growing
old and become ‘rejuvenated’. Conjugation is no doubt
the fore-runner of the sexual reproduction of higher creatures; it
is as yet unconnected with propagation and is limited to the mixing
of the substances of the two individuals. (Weismann’s
‘amphimixis’.) The recuperative effects of conjugation
can, however, be replaced by certain stimulating agents, by
alterations in the composition of the fluid which provides their
nourishment, by raising their temperature or by shaking them. We
are reminded of the celebrated experiment made by J. Loeb, in
which, by means of certain chemical stimuli, he induced
segmentation in sea-urchins’ eggs - a process which can
normally occur only after fertilization.
Secondly: It is probable
nevertheless that infusoria die a natural death as a result of
their own vital processes. For the contradiction between
Woodruff’s findings and the others is due to his having
provided each generation with fresh nutrient fluid. If he omitted
to do so, he observed the same signs of senescence as the other
experimenters. He concluded that the animalculae were injured by
the products of metabolism which they extruded into the surrounding
fluid. He was then able to prove conclusively that it was only the
products of its
own
metabolism which had fatal results for
the particular kind of animalcule. For the same animalculae which
inevitably perished if they were crowded together in their own
nutrient fluid flourished in a solution which was over-saturated
with the waste products of a distantly related species. An
infusorian, therefore, if it is left to itself, dies a natural
death owing to its incomplete voidance of the products of its own
metabolism. (It may be that the same incapacity is the ultimate
cause of the death of all higher animals as well.)
Beyond The Pleasure Principle
3750
At this point the question may
well arise in our minds whether any object whatever is served by
trying to solve the problem of natural death from a study of the
protozoa. The primitive organization of these creatures may conceal
from our eyes important conditions which, though in fact present in
them too, only become
visible
in higher animals where they
are able to find morphological expression. And if we abandon the
morphological point of view and adopt the dynamic one, it becomes a
matter of complete indifference to us whether natural death can be
shown to occur in protozoa or not. The substance which is later
recognized as being immortal has not yet become separated in them
from the mortal one. The instinctual forces which seek to conduct
life into death may also be operating in protozoa from the first,
and yet their effects may be so completely concealed by the
life-preserving forces that it may be very hard to find any direct
evidence of their presence. We have seen, moreover, that the
observations made by biologists allow us to assume that internal
processes of this kind leading to death do occur also in protista.
But even if protista turned out to be immortal in Weismann’s
sense, his assertion that death is a late acquisition would apply
only to its
manifest
phenomena and would not make impossible
the assumption of processes
tending
towards it.
Thus our expectation that biology
would flatly contradict the recognition of death instincts has not
been fulfilled. We are at liberty to continue concerning ourselves
with their possibility, if we have other reasons for doing so. The
striking similarity between Weismann’s distinction of soma
and germ-plasm and our separation of the death instincts from the
life instincts persists and retains its significance.
We may pause for a moment over
this pre-eminently dualistic view of instinctual life. According to
E. Hering’s theory, two kinds of processes are constantly at
work in living substance, operating in contrary directions, one
constructive or assimilatory and the other destructive or
dissimilatory. May we venture to recognize in these two directions
taken by the vital processes the activity of our two instinctual
impulses, the life instincts and the death instincts? There is
something else, at any rate, that we cannot remain blind to. We
have unwittingly steered our course into the harbour of
Schopenhauer’s philosophy. For him death is the ‘true
result and to that extent the purpose of life’,¹ while
the sexual instinct is the embodiment of the will to live.
¹
Schopenhauer (1851;
Sämtliche
Werke
, ed. Hübscher, 1938, 5, 236).
Beyond The Pleasure Principle
3751
Let us make a bold attempt at
another step forward. It is generally considered that the union of
a number of cells into a vital association - the multicellular
character of organisms - has become a means of prolonging their
life. One cell helps to preserve the life of another, and the
community of cells can survive even if individual cells have to
die. We have already heard that conjugation, too, the temporary
coalescence of two unicellular organisms, has a life-preserving and
rejuvenating effect on both of them. Accordingly, we might attempt
to apply the libido theory which has been arrived at in
psycho-analysis to the mutual relationship of cells. We might
suppose that the life instincts or sexual instincts which are
active in each cell take the other cells as their object, that they
partly neutralize the death instincts (that is, the processes set
up by them) in those cells and thus preserve their life; while the
other cells do the same for
them
, and still others sacrifice
themselves in the performance of this libidinal function. The
germ-cells themselves would behave in a completely
‘narcissistic’ fashion - to use the phrase that we are
accustomed to use in the theory of the neuroses to describe a whole
individual who retains his libido in his ego and pays none of it
out in object-cathexes. The germ-cells require their libido, the
activity of their life instincts, for themselves, as a reserve
against their later momentous constructive activity. (The cells of
the malignant neoplasms which destroy the organism should also
perhaps be described as narcissistic in this same sense: pathology
is prepared to regard their germs as innate and to ascribe
embryonic attributes to them.) In this way the libido of our sexual
instincts would coincide with the Eros of the poets and
philosophers which holds all living things together.