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Rh If the question be carried still further back and the behaviour of the cells themselves under radiation be considered, it has been found that the rays may act principally, though not exclusively, upon the nucleus or upon the cytoplasm or upon the cell membrane or upon any paraplastic material within the cell. The greater amount of work in this direction has been carried out with radium but there is little doubt that the effects of X-rays are similar. In part, changes are produced owing to the fact that the radiations break down complex chemical substances into simpler constituents. In this way, the osmotic tension of the cell or nucleus affected is raised and a dropsical condition results which can often be recognized microscopically. Other forms of degenerative change produced are fatty and mucoid. Thus radiation, if in great doses, will lead to fatty change in voluntary muscle of man and most animals or in renal cells of the cat. Under large doses of radium, mucoid changes are excessively common in all parts which normally produce mucus, but in addition, there is a great tendency for cells which ordinarily do not form mucus to undergo mucoid degeneration. Sometimes the cytoplasm of the cells disappears, though not obviously by way of either of these changes, with the result that the nucleus lies naked in the middle of the cell and separated from the cell membrane by a considerable distance. So far as the nucleus is concerned, changes produced by radiations may be intense. In cells such as those of testicle or intestine which are often found in mitotic division, mitosis is arrested or abolished. In other nuclei there may be evidence of vacuolation or the nucleus may be converted into a mere empty sac, or the nuclear membrane may disappear, or the entire nucleus may be represented by a few points of stained material or, finally, the nucleus may disappear altogether.

Thus in one or other way, changes are produced as the result of irradiation in the tissues upon which those rays impinge and the effects produced will depend upon (1) the type of cells affected, (2) the quantity of rays employed, (3) the length of time those rays have acted.

It must be remembered that the biological cell usually acts in one or other of two opposite directions when exposed to a physical agent according to the intensity with which the agent acts. Thus we distinguish between a stimulating or beneficial effect and an irritative or injurious effect. There is reason to believe that both of these may follow upon irradiation. In the case of malignant new growths, there is no doubt that death and destruction of the neoplastic cells occur where the rays act in all their intensity, but there is equally no doubt that because of the law of inverse squares and the specific absorption by the tissues a point is reached at which the injurious effect on the malignant cells which we desire passes into a stimulant effect which we may have reason to deplore. If this stimulus act on young and actively growing malignant cells at the periphery of the growth our irradiation will do more harm than good to the patient. There can be little doubt that in the early days of radiotherapy, some cases of malignant disease ran a more rapid course as the result of the irradiation treatment than otherwise they would have done. For this reason, the essential point of their treatment by means of radium consists in an endeavour to deal with the peripheral neoplastic cells.

On the other hand, changes may be produced in cells which we are unable to recognize microscopically. Recently the treatment of exophthalmic goitre has been largely and for the most part, successfully, carried out by irradiation and yet if the thyroid body be examined from animals exposed for many hours to the gamma radiations of radium bromide, it may be doubtful whether histological changes can be detected. Similarly, intense gamma radiation of the male frog produces no testicular changes that can be detected with certainty, and yet far less radiation produces marked changes in the tadpoles derived from normal ova fertilized by such radiated spermatozoa.

It follows from what has been said above, that radiotherapy is not without its special dangers. Amongst the disadvantages to which the irradiations may give rise, too extensive destruction of tissue on the one hand or stimulation of new growth on

the other are relatively obvious but the dangers are more insidious. Recent work has shown that long continued exposure to minute doses of radiation (in addition to the well-known occasional production of skin cancer) leads to blood changes which in course of time become a pronounced menace to life. Not only are red and white blood cells destroyed, but the rays appear to exert a deleterious effect upon the blood-forming tissues with the result that an aplastic anaemia becomes established. Obviously, the protection of the personnel in hospitals and similar institutions where X-rays and radium are used becomes a matter of great importance.

It is probable that X-rays and radium will always continue to be employed side by side owing to the special advantage which each form of radiation possesses, and in some cases it is certain that the best results are obtained in combination.

It will have appeared from what has been said above that radiotherapy is largely though by no means exclusively concerned with the treatment of new growths. Irradiation by one or other method is used in cases of uterine fibroid and in cases of inoperable cancer, sometimes with astonishingly good results. It is also used in conjunction with operation for cancer with the object of warding off recurrences. Sometimes cancers, inoperable when they first come under observation, are rendered operable by treatment with radium. And, frequently, when surgery has done all that is possible a considerable degree of relief is given by irradiation.

In addition to their use in the treatment of new growths, X-rays and radium have been tried in most of the chronic forms of disease. When surgery or medicine fails to relieve a case, it is usual to try irradiation. Sometimes the results are surprisingly beneficial, but the limits of utility of the rays still need to be determined.
 * (W. S. L-B.)

 RAEMAKERS, LOUIS (1869-), Dutch cartoonist, was born at Roermond, Holland, April 6 1869. He received his education in art at various schools, and finally at Amsterdam, where he obtained several prizes. He subsequently became director of an art school at Wageningen, in Gelderland. About 1908 he started drawing political cartoons, but it was not until the outbreak of war in 1914 that his work attained world-wide reputation, by his anti-German cartoons, illustrative of the devastation of Belgium and Northern France. Many special exhibitions of his war cartoons were held, and his work had a great effect as propaganda. Several volumes of his work have been published: The Great War in 1916; The Great War in 1917; Devant l'Histoire (1918); Cartoon History of the War (1919).  RAILWAYS (see ; also ).—.—In 1910 British railways had reached a high standard of completeness and development, and, although a number of new lines were subsequently brought into use, two only are of primary importance in regard to through main-line traffic. One of these is the first section of the Enfield-Stevenage line of the Great Northern railway, opened for traffic as far as Cuffley on April 4 1910. On the same date the Ashenden-Aynho line of the Great Western railway was brought into use for goods traffic. The former was part of a new line designed to afford an alternative route into London avoiding duplication of the Welwyn Viaduct and, by adopting a new route, opening up a new district near London for suburban development. From 1916 onwards the northern portion was laid with a single line and used for goods traffic, and towards the end of 1920 a second track was laid. In June 1921 this section had not yet been opened for passenger traffic, but was already being largely used for goods and mineral trains. The Ashenden-Aynho line was, however, on July 1 1910, brought into regular use as part of a shortened main route between London and Birmingham, and a two-hourly schedule then came into force for the principal Great Western expresses.

Among other important new lines brought into use the following may be mentioned: June 1 1910, Filton Junction and Avonmouth Docks, and the Camerton and Limpley Stoke lines, G.W.R.; Armagh, Keady & Castleblaney railway, worked by G.N.R. (I.), completed December 1 1910; April 13 1911, Shropshire & Montgomeryshire light railway; May 12 1911, Lampeter and Aberayron