The Nature of Man: Studies in Optimistic Philosophy

One of the oldest methods in the world consisted in bringing old men in contact with the bodies of young girls. David, King of Israel, employed this method, which at a much later period came into fashion. Eighteenth-century quacks proclaimed a number of specifics, among which was the " holy water " of Saint Germain, an infusion of senna, merely purgative in its effects. It is certain that some of the medicines used for the purpose, by emptying the large intestine, decreased the bacterial flora, and so checked the formation of the poisons that are harmful to the higher elements.

Hufeland,* a well-known German professor, published towards the end of the eighteenth century, a work called " La Macrobiotique " ; or, " the Art of Prolonging Human Life." This treatise had a great vogue in its day, and contained many interesting and just observations. Besides advoca- ting cleanliness and moderation, Hufeland advised that " we should use vegetable rather than animal food, as animal food was more liable to putrefaction, whilst vegetable sub- stances contained an acid principle that retarded our mortal enemy, putrefaction." f Here the physician of a day long past anticipated one of the discoveries of modern science.

In our time scientific men have not ceased to concern themselves with the prolongation of human life. Professor Pfliiger, of Bonn, one of the most distinguished of living physiologists, has published an essay* in which he gave the results of his inquiries into this subject. He first stated that investigations into the habits of those who had attained a great age did not give information sufficiently exact. Pfliiger laid stress on the' means of avoiding infectious maladies, and summed up as follows : " Finally, I can do no better than to associate myself with the advice given in all the treatises on the prolonging of life : avoid the things that are harmful and be moderate in all things."

A year later, a well-known German physician, Dr. Ebstein§ published a very careful treatise on the same subject. He had been struck by the fact that among those who have reached a great age, there have been several who had led * " L'Art de Prolonger la Vie Humaine." French translation of German Second Edition. Lausanne, 1809. \ " Ueber die Kunst der Verlangerung des Menschlichen Lebens." Bonn, 1890. § " Die Kunst das Menschliche Leben zu Veriangern." Wies- baden, i SQL

an exuberant life, full of excesses, notably in the consump- tion of alcohol. None the less, Ebstein advised either a complete avoidance of alcoholic liquor, or at the most an extreme temperance in the use of it. He prescribed in addition the simplification of the conduct of life and the avoiding of anything that is unwholesome. Study of surh works, which are written in a scientific spirit, convinces me that a science of the prolongation of life could be built up. An exact investigation of the pheno- mena of old age would contribute to this object. At any rate, we cannot set aside as chimerical plans to make old age a natural process, and one easy to bear. I believe, moreover, that attempts to prolong life deserve to be encouraged, the more so as instances of longevity are already numerous.

Quite a number of cases of centenarians who have pre- served intellect and vigour until death have been recorded, (t is unnecessary to relate the histories of these persons, ;f whom some attained such ages as 120, 140, and even '85 years (Saint Mungo of Glasgow). My friend, Professor .Ray Lankester,* thinks that such unusually old persons are monstrosities comparable with those who have attained a gigantic stature. But centenarians are more numerous than giants, and while the latter exhibit marked signs of pathological weakness the former surprise us by their health and vigour.

The longevity of the Israelites recorded in the Old Testa- ment is well known. No doubt there is much exaggeration in these naive records. Was it an error of exaggeration to impute an age of 969 years to Methusaleh, or of 595 to Noah, or were these ages reckoned on a different basis ? Henseler f suggested that in these cases each season wa3 f Quoted by Pfliiger in :' Ueber die Kunst der Verlang.," p. 14, counted as a year, so that the age of Methusaleh was really only 242 years, a length of life not so vastly greater than ages recorded in modern times.

There is evidence to show that in somewhat later Biblical times ages were reckoned in our years. Thus in the Book of Numbers (i. 3, 20, 22) reference is made to those " From twenty years old and upward, all that are able to go forth to war in Israel." The limit of age given shows clearly that the years counted were our years. This interpretation is supported by many other passages in the Pentateuch, notably where annual harvest feasts are spoken of. We may therefore accept as probable the assignment of such ages as 100 or 120 years to several Biblical personages, such as Aaron, Moses, and Joshua. And the words put in the mouth of J ah veh may be accepted as important evidence : " And the Lord said, My spirit shall not always strive with man, for that he also is flesh : yet his days shall be an hun- dred and twenty years." *

The longevity of that remote period must have surpassed the age of the present time. From the circumstance that the greatest number of deaths occurs at the age of seventy years, Ebstein f has inferred that seventy years is the normal duration of life. Although there is no doubt but that the duration of human life has become longer in the nineteenth century, we must believe that it was still longer in Biblical times, a fact that is not particularly surprising.

I have called attention to the important influence of syphilis in inducing premature and pathological old age, as that disease is a chief cause of arterial sclerosis and degeneration of the higher elements of the body. Syphilis has an influence still more serious because its effects are inherited. Now although the Bible refers to diseases oi * Genesis vi. 3. f Loc. cit. p. 12, the genital organs and lays stress on circumcision, there is no direct evidence in it as to the existence of syphilis. Ebstein, in a treatise on the medicine of the Bible,* is confident that there is no reference to syphilis in that Book. Moreover, in the ancient world generally, syphilis was either unknown or existed only in an attenuated form. Haeser,| the author of the best modern treatise on the history of medicine, thinks that if syphilis did exist in the ancient world, it occurred in a localised form and did not become a general disease of the system as is the case among the moderns.

Humanity would make a great stride towards longevity could it put an end to syphilis, which is the cause of one- fifth of the cases of arterial sclerosis. The suppression of alcoholism, the second great factor in the production of senile degeneration of the arteries, will produce a still more marked extension of the term of life. Scientific study of old age and of the means of modifying its pathological character will make life longer and happier. Although modern knowledge is still imperfect, there is no reason to be pessimistic on the subject of old age.

Theory of the immortality of lower organisms — Immortal- ity of the sexual cells in higher organisms — Immortality of the cellular soul — Occurrence of natural death in the case of certain animals — Natural death in the Ephemeridae — Loss of the instinct of preservation in adult ephemerids — In- stinct of life in the aged — Instinct of natural death in man — Death of old men in Biblical times — Changes in the in- stincts of man and lower animals FROM what I have said in the last chapter, it is plain that, perhaps before very long, it will be possible to modify old age. Instead of retaining its existing melancholy and repulsive character, it may become a healthy and endurable process ; it may also be that the duration of life will be prolonged. However, it may be asked, what shall we gain by attaining the age of 100 or 120 years instead -t>f 70 or 80, if there still remain for us the appalling fate of the inevitable annihilation of death. Marcus Aurelius said that he who makes a long journey and he who makes it short, alike meet death at the end ; and that once they are over, three years or a century are much alike. Such assertions, however, do not take into account the difference in the values we set on a thing at different ages A man of the age of twenty-five years and one fifty years old reason differently, and are affected differently by the same surroundings. The outlook on life changes in the same

individual as he gets on in years. Young people judge of their impressions by comparison with their ideals, and as the latter are very high, they are dissatisfied with things as they really are. They are exacting, and discontented with what they can get out of the real world; grown up people and those of advanced years are more easily satisfied because they have a clearer knowledge of the true value of things. As I have already had occasion to point out in a previous chapter, the young are more inclined to pessimism than the old. We see, then, that appreciation of life changes with age. It is the same with regard to death. It has often been said that life is only a prepara- tion for death. Cicero said, " From our youth upwards we must accustom ourselves to face our last moments without fear. If not, there is an end to peace, since it is quite certain that we must die." Philosophy has been called the art of preparing for death.

Before considering in what direction science may direct our steps towards solving the problem of death, which in the words of St. Paul is the " last enemy to be destroyed," let us see how much is known about it. We are so accustomed to look upon death as something natural and inevitable, that it has long since come to be regarded as inherent in organisms. However, when biologists investigated the matter more carefully, they failed to discover any proof of the accepted doctrine. Observation of members of the lowest grade of animal life, such as infusorians and other protozoa, has shown that these reproduce by simple division, and in a very short time multiply to an astonishing extent. Generation succeeds generation, with the utmost rapidity and without the intervention of death ; no single corpse appears in the swarming masses of animalculae. From such facts,

which are extremdy easy to confirm, several biologists, and in specially Biitschli and Weismann,* have deduced an immortality of the unicellular organisms. When an infusorian has divided, each daughter organism rapidly completes itself and sets about again dividing in the fashion of its parent. The process may be more com- plicated, as in the cases where a single organism breaks up into several portions each of which contains an essential part of the parent organism. Many unicellular organisms reproduce in such a fashion, and as each animal divides simultaneously into a number of individuals of the new generation, the individuality is destroyed. It is possible to admit with Gotte f that such a process is natural death, although there is no actual destruction and no corpse.

In any event it cannot be disputed that lower organisms are not subject to the natural death that comes inevitably to man and the higher animals. It has been suggested that the debility of infusorians after a rapid series of divisions, and before conjugation, is to be interpreted as natural death. But the rejuvenescence that follows con- jugation is incompatible with such an interpretation. Moreover, when conjugation does not occur, and the debility leads to death, the deaths must be regarded as accidental.

The theory of the immortality of unicellular organisms is now generally accepted. However, there are animals, higher in the scale of life, to which natural death does not come. Among these occur certain forms of considerable complexity, composed of many organs and very many cells, such as many polyps, and some worms, especially annelid worms. Some annelids (Fig. 17) reproduce by transverse divisions very actively. " Throughout the summer," said E. Perrier,* " the Naidimorpha are devoid of genital organs, and appar- ently (according to unpublished observations of Maupas), they may be kept alive for several years, and perhaps indefinitely, in this sexless condition ." This certainly may be regarded as a case of immortality due to the indefinite power of regeneration possessed by a complex animal.

The facts that I have cited show that death is not necessarily inherent in living organisms. Naegeli,f a well-known German botanist, has asserted even that natural death does not exist in nature. He points out that trees, more than a thousand years old. perish not by natural death, that is to say, by the gradual decay of their vitality, but by some catastrophe. The age of the famous dragon- tree of the Villa Oratava at Tene- riffe, admired by Von Humboldt, Fia [7>_ Chatoglls(er about to divide

Was estimated at Several tllOU- into four (from a drawing by M.Mesnil). sand years. Its trunk was hollow, but the huge monster continued to flourish until it was overthrown by a storm. t " Abhandlungen der k.bayrischen Akademie d.Wissenschaften,*1 If was only by a catastrophe that the long-lived giant perished. The Baobab is reputed to live for five or six thousand years. In a recently published essay, Jacques Loeb,* a dis- tinguished biologist in Chicago, has made a study of natural .death, and has come to the conclusion that there is no good evidence for its existence. He has observed that ripe, but unfertilised eggs of sea hedgehogs (Echini) die a few hours after they have been discharged. Loeb thinks that this may be a case of natural death, but I cannot agree with this opinion, as an egg that has not been fertilised by a spermatozoon may be compared with an organism deprived of its nutrition and so dying of starvation. In both cases death is purely accidental and could have been avoided.

If natural death does exist, it must have appeared on the face of ' the earth long after the appearance of life. Weismann has suggested that death arose as an adaptation for the advantage of the species, that is to say, in relation to the surrounding conditions of existence, and not as an absolute necessity inherent in the nature of the living substance. He thought that as worn organisms are no longer suited for reproduction or for the struggle for life, natural death was due to natural selection, it being necessary to maintain the species in a vigorous state by weeding out the debased individuals. But the introduction of death for that purpose was superfluous, since the debility caused by old age in itself would eliminate the aged in the course of the struggle for existence. Violent death must have appeared almost as soon as living things came into being. The infusorians and other low organisms, despite their

* " Archiv fur die gesammte Physiologic" Vol. XCIII., p. 59, potential immortality, must have been subjected perpetually to violent death, falling victims to larger and stronger organisms. It is impossible to regard natural death, if indeed it actually exist, as the product of natural selection for the benefit of the species. In the press of the world natural death rarely could come into operation, because maladies or the voracity of enemies so frequently cause violent death.

No doubt a certain number of deaths are recorded in statistics as being due to old age, without visible malady. Sometimes decrepit old men feel no pain and seem to fall quietly into their eternal sleep • but autopsy reveals serious lesions of the internal organs. There is reason to believe that even such deaths are in reality violent and are usually caused by infectious microbes. The general effect on the mind produced by examination of the collected facts is not an acceptance of the view that natural death is essentially inherent in living organisms, but the production of a wish to discover if there be any real proof of its existence.

For some time natural death has been ascribed only to the parts of the body that are of use in the individual life. Those cells, the function of which is to secure reproduction of the species, are, like unicellular organisms, potentially immortal. The egg-cell of the female is transformed into a foetus, and so is the starting-point of the new generation, while the sexual cells of the new generation give rise to the third generation, and so on, in an endless chain of life. The greater number, by far, of the eggs and spermatozoa perish ; but their death is not natural but violent, being due tc harmful external agencies. An infinitesimal minority of the sexual cells survive indefinitely in the successions of genera- tions.

Scientific proof exists, therefore, that our bodies con- tain immortal elements, eggs or spermatozoa. As these cells not only are truly alive but exhibit properties that are within the category of psychical phenomena, it would be possible to build up a serious thesis on the immortality of the soul. Observations on protozoa, and especially on the in- fusorian group of protozoa, show that these simple beings, each of which is composed of no more than a single cell, pos- sess a high degree of sensibility. They select their food, distinguish living from dead animalculse,* seek out their mates for conjugation, avoid danger, and hunt their prey ; in fact, they are in possession of a set of qualities that must be included in psychical phenomena, Although such phenomena are very much lower in the case of the in- fusorians than in the case of higher animils, it is possible to speak of the soul of protozoa. Moreover, as the body is immortal by reason of its indefinite power of reproduction by division, the soul also of these creatures is immortal. However, the soul is so primitive that it is impossible to speak in definite terms about it.

As the sexual cells of the human body are immortal, like the protozoa, the problem arises if these too be endowed with an immortal soul. Our existing knowledge makes it impossible to doubt that ova and spermatozoa have sensibility in a degree as high as that of the protozoa. The ova shed secretions that arouse the sensibility of the spermatozoa, and the latter, directed by this specific " odour " (the occurrence being known technically as chemotaxis),make their way to the ovum and penetrate it. Some substances, arousing the spermatozoa into a.ctivity

* Salomonsen, in " Festskrift ved indvielsen af Statens Serum Institut," vol. XII. Copenhagen, 1902. and movement, attract them, others repel them. The phenemona of chemotaxis were shown for the first time in the case of cryptogams by Pfeffer, the distinguished botanist, and since then the male cells of many plants and different kinds of animals have been proved to possess sensibility. When ova and spermatozoa succeed in conjugating, they produce an individual of the next generation, to which they transmit what Haeckel has called the " cellular soul." * This soul, then, is really immortal, inasmuch as the bodies of the reproductive cells are immortal.

Although it is true that our bodies contain elements endowed with immortal souls, it by no means follows that our conscious souls are immortal. In an earlier chapter, I have already pointed out that the psychical phenomena of many of the cells of our body and the cellular sculs of these are outside our consciousness. We have no consciousness of the perpetual battle waged by the phago- cytes against the microbes that endeavour to obtain a foothold in our tissues. None the less the phagocytes are elements endowed with mobility and sensibility and possess- ing a cellular soul like that of the protozoa.

A woman has no consciousness of. the numerous sperma- tozoa, with their cellular souls, that enter her body, nor of those that fertilise her egg-cells ; she is even without consciousness of the much more highly developed soul of the foetus. A child before birth possesses psychical qualities much more numerous and more perfect than those of the reproductive cells. It is capable of responding to certain sensations and of performing movements. A child, in the later months of its prenatal existence, possesses the senses of touch and taste and, within limits, the sense of * " Gesammelte Populare Vortrage." Bonn, 1878,

sight.* This soul is outside the consciousness of the mother. The mother cannot even tell by her consciousness if she bears under her girdle one or two embryonic souls. And so the immortality of the cellular soul has no relation to the problem of death- It is a common opinion that only the reproductive cells of man and animals are immortal, and that the other elements of the body are mortal, the latter, if they escape violence, dying a natural death. A contrast has been drawn between the mortal cells in which is .resident the life of the body and the immortal cells on which the species depends. However, when non-reproductive cells possess the power of regeneration, it is impossible to deny their immortality. When a polyp or a worm reproduces by division, a large number of cells go to form the new individual, and these cells are immortal in the fashion of the infusoria,

Immortal animals occur only among the lower inverte- brates. The power of regeneration fades away in the higher ranks of the scale of life. Whilst worms may be divided in several pieces, each piece being capable of regeneration so as to form a new worm, when molluscs are cut they display only a limited capacity for regeneration. If the antennae of a snail be amputated they will be renewed, but if the whole creature be cut in pieces death follows, Some of the lower vertebrates, such as newts and sala- manders, can renew the tail and the limbs, but they cannot reproduce by division. Birds and mammals, the higher vertebrates, have very little power of regeneration, and +ail and limbs are never reformed in their cases.