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This shows us that within a single cycle of life differentiation may take place in two entirely different directions. The same original egg turns first into the worm-like, leaf-eating feedingmachine which we call a caterpillar, and later into a beautiful winged creature, honey-eating, active, concerned chiefly with reproduction. But the one form cannot turn directly into the other. The old must be broken down, and the new built from the foundations up. What is true of bodily differentiation here is true of mental differentiation in ourselves. It often happens that a man's mind is differentiated very highly in one direction early in life; and that, later in life, the same man will have acquired a quite different type of mind; but in the intervening period there will have been, almost without exception, a difficult time of transition, in which the old system was being broken down, the new built up. But that is a digression. Let us hope that by now the reader's general ideas on growth, differentiation, and death will have been thoroughly upset! If so, we can proceed to discuss the control of growth more systematically.

In a simple but classical experiment of Hertwig's, a batch of frogs' eggs was divided into four portions. One was kept at 11.5 degrees Centigrade, one at 15 degrees, one at 20 degrees, and the fourth at 24 degrees. After three days, the first had not completed their primary ground-plan, and were still simple spheres; the last were ready to hatch; and the other two were intermediate. It is obvious that higher temperature goes hand in hand with quicker development. That is a practical, tangible fact. But it raises at once a philosophical problem of the most searching kind. It raises the problem, which in another form has been propounded by Professor Bergson, of the relation of time to true being.

What is the true age of these four batches of embryos? They have all been alive the same length of days, hours, and minutes. But each has accomplished a different portion of its essential cycle of being, each has penetrated a different distance along the road which leads to old age and death. Judged by outer standards, they are of the same age; judged by standards relative only to themselves, they are all of different ages. This, you will see, is the same distinction on the physiological plane that Bergson has found it necessary to carry out on the psychological plane. To point the moral, we will take a further example, and this time one involving the end of life instead of the beginning.

As is well known, many insects live but a short time—some of them only a few weeks, or even a few days. Now this span of life, too, is a function, in the mathematical sense, of temperature. At a high temperature it is shortened; at a low temperature, lengthened. For instance, Professor Loeb has investigated the duration of life of a little fruitfly, Drosophila by name. At 30 degrees Centigrade the length of life, from hatching to dying, was 21 days; at 20 degrees it was 54 days, and at 10 degrees 177 days, or nearly six months. Thus the processes which lead up to and involve death are accelerated by heat. What is more, they are accelerated in a regular manner, and in essentially the same way and degree as are all ordinary chemical reactions. The rate of most chemical reactions is roughly doubled or trebled for each increase of 10 degrees Centigrade within the range of temperature within which life is possible; and so are the processes of life. The fly lives more intensely at the higher temperature; but it draws proportionately nearer to its death a situation not unlike that in Balzac's Peau de Chagrin.

Once more the question is raised

whether age should be reckoned from the outside or from the inside. We shall have to return to that question later, and, I hope, settle it. Here we must go back to the more specific point, the action of different temperatures.

This extraordinary diversity in rate of growth or rate of ageing with different temperature, which we find in frog and fly, and indeed in all the lower animals, does not exist for man or mammal or bird. Why not? For the reason that, as regards temperature, we and these other creatures are self-regulating. We are what is popularly called warmblooded; which really means not warmblooded at all, but constant-temperature-blooded. Warm-blooded animals have contrived an internal temperature environment for themselves, which is, within very wide limits, independent of the temperature changes taking place in the world outside. The development of such self-regulating mechanisms, indeed, some regulating temperature, some the chemical composition of the blood, some operating psychologically, has been one of the great achievements of evolution, and the relative independence accruing to their possessors is one of the hall-marks of a higher type.

It is thus obvious that we shall not be able to alter the rate of growth in man by altering the temperature, for the simple reason that we cannot alter the temperature.

Such failures pursue us throughout our investigation; again and again we find that in some lower animal growth or length of life can be controlled, only to discover, when we seek to apply our knowledge to man, that there stands in the way either his very complexity or the exquisiteness of his self-adjusting machinery, which resists the efforts made to tamper with it.

In the higher animals, the regulation of growth is largely carried out by the organs known as the ductless glands, of

which the best known are the thyroid and adrenals. The origin of our knowledge of the normal, as so often, came from a study of the abnormal; and it was through an investigation of the diseased state known as cretinism that we gained the first inkling of the functions of the thyroid.

Cretins are stunted in a particular way, both in body and mind. Their condition was found to be associated with a diseased and insufficient thyroid gland. Finally, treatment with preparations of thyroid led, in most cases, to the transformation to a healthy, normal individual.

Many of the processes of life in cretins appear to be slowed down. This is seen, too, in the disease known as myxoedema, where the thyroid becomes diseased during maturity. In patients suffering from this, the skin becomes thick and whitish, the features heavy, and, most marked symptom of all, the mind grows distressingly slow. Here again simple restoration of the proper thyroid balance usually leads to recovered health.

Acromegaly is another curious disease. In sufferers from this, there is a progressive increase in the bony structures of face and extremities, patients having to discard their old gloves and shoes, and take to larger and larger sizes. Worst of all, the features get heavy and coarse, and the most attractive men and women are transformed into hateful caricatures of their original selves. Autopsies show that this disease is associated with a diseased and overgrown condition of the pituitary body, another ductless gland attached to the base of the brain. The very tall men, the giants of fairs and circuses, in whom the whole body shoots up abnormally in height, seem to be produced by a similar state of the pituitary, but operating earlier in life, while the bones are still growing.

By these observations it became clear that both thyroid and pituitary were in some way connected with growth. Experiment has extended our knowledge. We have already spoken of the protozoa in general and paramecium in particular. Paramecium, when thyroid powder is added to its diet, reacts by an increased division-rate. As we have seen, it reproduces by simple division into two, each of which then grows up to its parent's size and repeats the process. If we average out the number of times this occurs per day, we have a measure of the reproductive capacity of the strain. Now, the division-rate of thyroid-fed paramecium was 60 per cent above that of the normals. In other words, where the normal had divided five times, to produce 32 offspring, the thyroid-treated cell had divided eight times, to produce 256 offspring; where the one had accomplished ten divisions, the other had accomplished sixteen, and the offspring, if all had survived, would have been in the ratio of 1,024 to over 65,000. But all the time the appearance of the paramecia was very like that seen when they are starved; and this is corroborated by the fact that excess of thyroid administration in man leads always to increased appetite and decreased weight. Apparently the effect of thyroid is to liberate

the stored energy of living protoplasm, to cause some of the breaking-down or katabolic processes of life to go on at a higher rate. In paramecium this can be just compensated for. A thyroid-fed strain of paramecium is like a man living comfortably, with a good income, but always with a slight debit balance at the bank. In man, however, it would appear that long-continued administration of thyroid in any quantity progressively overdraws the balance, and is not compatible with health. Paramecia fed with pituitary, on the other hand, also divide more rapidly, but do not show any untoward symptoms. The converse experiment is to subtract pituitary from the organism. Young dogs from which some of the pituitary has been removed grow extremely slowly, become excessively fat, and in many ways remain in an infantile stage.

Professor Arthur Keith has recently made the interesting suggestion that the difference in racial type, as seen for instance between the white, the yellow, and the black races, is due to alterations in the balance of the various glands of internal secretion. By this means, too, he seeks to explain the occasional appearance in white races of individuals of a Mongolian cast of face, where no admixture of Mongolian blood exists.

BY TARAS SCHEVTSCHENKO

[The following letter by the greatest of the Ukrainian poets of liberty was written in 1860. It contains a short sketch of his life up to 1844, which he later used in a biographical romance. In 1845 he returned to Ukraine, where he was arrested and banished to Siberia on account of his revolutionary poems. There he was forced to serve as a common soldier and forbidden either to paint or to write. He was pardoned in 1857 at the intercession of Count Tolstoy; but his health was broken, and he died at Petrograd less than four years later.]

From Die Rote Fahne, April 26, 27
BERLIN OFFICIAL COMMUNIST DAILY

I AM happy to assist you in your wish to give your readers some biographical information regarding the men who have succeeded in struggling out of the ignorance to which the mass of our countrymen are doomed. Narratives of this kind may, it seems to me, help to awaken in our people a sense of human dignity, without which their progress will remain impossible. My own life story, truly told, may suggest helpful thoughts not only to the common man, but also to the man of higher social rank. It is for this reason that I am willing to bare to your readers the sad incidents of my own history. I would have preferred to do this at some length, if at all, especially since the history of my life has become a little fragment of the history of my homeland. But I now lack the strength and spirit to attempt this. For that task a man should be blessed with mental repose and feel more or less in harmony with the men and things about him. All I can do to comply with your wish is to give a brief sketch of my life-experience. When you have read the following lines, I hope you will comprehend the load that lies upon my heart and crushes it.

I am the son of the peasant serf, Gregory Schevtschenko, and was born on March 9, 1814, in the village Kirilovka, in the district of Svenigoroder,

in the government of Kieff, upon my lord's estate. When I was eight years old, I lost both my father and my mother and was received into the family of the parish clerk as a student servant.

Such students are treated by the parish clerks like children whom their parents or the local authorities have apprenticed to tradesmen. Their master has unlimited authority over them. They are his slaves. They must perform every kind of menial household duty and do the bidding not only of the master himself but also of his servants as well. I leave it to your imagination to picture all the things my parish clerk found for me to do. He was a brutal drunkard. I was in a state of servitude, without having a single person in the world who cared for me or took the slightest interest in me. In spite of that, however, I managed to pick up in the course of a couple of years some knowledge of the violin, of arithmetic, and the Psalter. When I had made this much progress, the clerk proposed that I should read the Psalter in his place at peasant funerals; and was so gracious as to let me keep the ten kopecks usually paid for that service. This help left my morose master more leisure for carousing with his bosom friend, Jonas Limer. When I got back from my burial services, I

usually found these precious companions dead to the world with drink.

My parish clerk was as brutal to his other pupils as he was to me, and we all hated him beyond measure. His capriciousness and cruelty taught us to deceive him, and to do him injury whenever possible. We played all sorts of scurvy tricks on him.

This was the first despot whom I learned to know. He taught me the inextinguishable hatred I have ever since felt for the tyranny and domination of one man over another. My child's heart was wounded and shocked at every turn by this despotic schooling and hardened itself against the world, the way the hearts of helpless men always harden themselves until, at length, patience ends and vengeance and flight ensue. One day when I found him lying in a drunken sleep, I seized his own rod and applied it on him with all my childish strength in repayment for his cruelty to me.

In my eyes, the most precious thing among the scanty effects of this drunken clerk was a little book illustrated with crude engravings. I either thought it no crime, or could not resist the temptation to steal this treasure; and I fled with it to the little town of Lesjanka.

At that place I found a new teacher in the person of an artist and deacon who, as I soon discovered, was as like my previous master in morals and general conduct as if they were two peas. For three days I patiently toiled, carrying pails of water up the steep hill from the Tikatsch river and grinding colors on an iron plate. On the fourth day, I had enough of it and fled to the village Tarasovka, to a painter clerk who had acquired some reputation in the neigh borhood by his pictures of the martyr Nikita and of Ivan Vohin, the warrior. I appealed to this Apelles with a firm resolve to endure all the burdens of fate which seemed to me at that time

inseparably connected with the pursuit of learning. But alas! The Apelles observed my left hand carefully, and bluntly rejected my appeal. He informed me, to my indignation, that I was not qualified for any occupation, not even that of a cobbler or a cooper.

So I gave up all hope of learning painting, even its most mediocre branches, and returned with a heavy heart to my native village. I had conceived visions of a more modest career, which charmed me on account of its very simplicity. I longed, as Homer says, to 'shepherd the innocent flocks,' fancying that while thus engaged, I would have an opportunity to read undisturbed my treasured, stolen picture book. But I met another disappointment here. I chanced to catch the fancy of my young manor lord, who had just taken possession of his ancestral estate, and so the ragged student tramp was given a decent suit of clothes and a job as valet.

We owe the discovery of this refining occupation in the Ukraine to those civilizers from beyond the Dnieper, the Poles. Our native landowners have gradually adopted this valet institution from that source. But training the natives of this old Cossack region as lackeys is about as easy as it would be to tame Lapland reindeer as parlor pets. The landlords of the older generation had attendants the so-called Kosatchki - who performed the duty of body servants, indeed, but also were musicians and fancy dancers. These Cossack liegemen played and sang merry songs of dubious import for the delectation of their lords, and dropped on their knees at a motion from his hand in the formal courtesy which preceded the swift dance step. My new master was, by descent, a Russianized German. He viewed my duties from a coldblooded, practical point of view, and posted me in the corner of his ante

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