pure emanations of radium. In other words, one element had been observed to change into another. Continued investigation to the properties and characteristics of the radio-active substances, uranium, thorium and radium brought to light many interesting and illuminating facts.

Mr. Frederick Soddy, a collaborator of Sir William Ramsay, announced the property possessed by thorium and radium of imparting radio-activity to any body with which they come in contact. The excited activity was not found to last, but, just as in the case of the emanation noted above, it disappeared in the course of time. The half value in the case of thorium was reached after a lapse of eleven hours, and in the case of radium after a few minutes. Thus radium gives a longlived emanation, producing a short-lived activity. In thorium, just the opposite result obtained. Mr. Soddy established that the power of thorium to give its emanation is, like its power of radiating, the result of a process which is spontaneous and which it is not possible to control or alter to a measurable extent by any known agencies. Even the life of the emanations was unaffected by the most diverse circumstances. The experiments of Sir William Ramsay and Mr. Soddy, and the discussions aroused by them, emphasized two points: First, the continual production of an active matter of a new kind; second, the decay of the activity of the matter so produced with time.

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Experiments made by Mr. R. J. Strutt led to the conclusion that radium is at least 100,000 times more active than uranium, that uranium is 3,000 times more active than the most common active material among ordinary substances, that a slight amount of a radio-activity is associated with all solids, and that the so-called "spontaneous ionization of air is due to slight activity of the walls of the vessel containing it. To test this view Mr. Strutt experimented with a glass cylinder closed at one end by a plate of glass, cemented, and which could be removed so as to introduce linings of different materials. He found rates of leakage varying from 3.3 scale divisions per hour in the case of tinfoil to 1.3 in the case of glass coated with phosphoric acid. In platinum the rate of leakage for different samples was 2.0, 2.9, and 3.9 divisions per hour. Thoroughly oxidized copper showed a rate about three-quarters that of polished copper.

THEORIES OF EVOLUTION

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At a meeting of the British Association for the Advancement of Science, Charles Vernon Voys, president of the physical section, declared that the discoveries regarding radium transcended all others in intrinsic importance and revolutionary possibilities. "Its everlasting production of heat, which can barely be distinguished from perpetual motion, has left every chemist and physicist in a state of bewilderment." The members of the Association held to two general theories to account for the phenomenon: The old one of conservation, to the effect that radium is slowly losing the amount of energy it gives off; and the new one that, in some mysterious way, radium catches and transmits energy from the outside.

IV

Professor Arthur W. Goodspeed of the University of Pennsylvania, exhibited photographic negatives which gave the outlines of small objects as produced by the radio-activity of the human body. To accomplish this result he used a Crookes tube as an intensifier, but directed the rays of the tube away from the box containing the photographic plate. His own hand was then held near the plate for three minutes, and the objects that had been set on the plate were shown in the resulting negative. Dr. Goodspeed's experiments showed that this radio-activity was only transient, ceasing as soon as the current ceased in the tube. They illustrated very clearly the action of the secondary or induced rays. All objects in the vicinity of the X-Ray tube became active under the influence of the secondary rays.

Theories of Evolution

A Dutch naturalist of international reputation, Hugo de Vries, announced a new theory of evolution. He proposed to substitute what he called "the theory of mutation" for the old hypothesis of natural selection. He denied the possibility of the gradual transformation of the species by the addition of various insensible aspirations. He claimed that such variations are produced by a rapid, precipitate and sudden process, the new species whose creation he has observed being produced by what he calls "spasmodic process." The eminent naturalist claimed that his theory was based entirely upon experience, and that he did not hesitate to oppose it to the Darwinian theory. As the

best proof of his theory he offered a record of his experiments with the onagre biennial. This plant was sown in the botanical garden of Amsterdam and was observed from 1886 to 1900. In 1887 a new type appeared, in 1888 two new species, and in 1900 in eight generations de Vries obtained out of 50,000 plants which came from seeds 800 new individuals belonging to seven unknown species. Thus we have 800 individuals out of 50,000, which are undergoing the process of specific transformation. The activity of the change which this plant underwent was about 1.5 per cent. The new species in no wise resembled the old, they appeared suddenly without preliminary or intermediary.

II

On the other hand, Dr. J. L. Wortman, who had spent three years conducting researches in the Marsh collection of fossil vertebræ in the Peabody Museum at Yale, presented newly discovered evidence in support of the Darwinian theory in a series of papers in the American Journal of Science. In discussing the development of monkeys to the point where it became possible for man to branch off, Dr. Wortman opened up several entirely new avenues of evidence, to prove that the monkey mind evolved from that of the lower types of animals, both by the influence of habits of attention, brought about by the ability to examine objects with the hands, and by the more vigorous blood supply to the brain afforded by the cerebral blood circulation peculiar to the higher types of the primates and to man himself.

III

A prominent German anthropologist, Dr. B. Hagen, announced a theory that the change in man from his original shape took place in Europe. He based his conclusion on his discovery near Krapina, in Croatia, of ten skeletons, the flesh of which had evidently been eaten by cannibals. Dr. Hagen judged from the appearance of the bones that the speech muscles were only slightly developed in those persons, and that they could not speak, as language is understood now. They had huge heads, broad faces, with flat noses, strong masticating bones and muscles, short legs, and arms of medium length, and the greater part of their bodies was covered with coarse reddish hair.

NEW PLANTS

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New Plants and Animals

The discovery of a new parasite was announced at the zoological station at Naples. A number of distinguished scientists had collected from the Mediterranean Sea quantities of a certain fragile mollusk called phyllishöe, a shellfish lacking a shell, transparent and colorless, but dotted over with phosphorescent patches making it luminous at night. There was noted a peculiar structure depending from its lower side that was not understood until the specimens had been given a more careful examination, when it was found to be not a part of the mollusk at all but a separate organism attached to it. This parasite was pronounced to be one of the jellyfishes, and the first instance of parasitism known among them.

A new plant was discovered in South America containing a considerable quantity of saccharine matter. The plant was of the species Eupatorium, canabinum, herbaceous, from 8 to 12 inches high, and said to yield a sugar from twenty to thirty times as sweet as ordinary cane or beet sugar.

CHAPTER XI

THE WAR AGAINST DISEASE

Wonderful cures effected by the light treatment discovered by Dr. Niels R. Finsen, of Copenhagen, had aroused so great interest in America that the year 1903 was marked by an influx of American doctors into the Danish capital. At least seventy-five American doctors from all sections of the United States visited the Finsen's Medical Light Institute at some time during the year. Many of these physicians purchased Finsen lamps with a view to establishing institutes for the treatment of skin diseases by Dr. Finsen's method. Eight American patients were treated at the institute during the year with satisfactory results. The American doctors who remained in Copenhagen a sufficient length of time to make a thorough study of the work of the institute declared that, while the principle of the light cure is simple, the actual work of administering it is a slow process.

Finsen's Medical Light Institute, established in 1896, had become a State Institution in 1903. According to a report published in May, of 1,367 cases received for treatment up to that date, at least 1,000 were lupus vulgaris, one of the most disfiguring diseases known. Other diseases treated and cured during the same period were: Lupus erythematosus, 92 cases; alopecia areata, 77; epithelioma, 60; acne vulgaris and rosacea, 62; nævus, 44; tuberculosis verrucosa, 22. Of the lupus vulgaris cases 51 per cent were apparently cured, 24 per cent almost cured, 11 per cent decidedly improved, 5 per cent unsatisfactory, while 9 per cent disappeared from observation. Lupus vulgaris is a disease little known in the United States, though quite common in Denmark, Germany and northern France, in which countries it is claimed that one person in ten thousand is afflicted with this disease. This disease is caused by the growth of tubercle bacilli in the skin. It has its inception, as a rule, in catarrh. Poor sanitary conditions and a moist climate