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108 details. Some doubtless felt disheartened because of lack of opportunity, as did the Edinburgh anatomist, Dr. John Barclay a century ago. Dr. Barclay looked upon the great anatomists of earlier periods as "reapers who, entering upon untrodden ground, cut down great store of corn from all sides of them. . . . Then come the gleaners who gather up ears enough from the bare ridges to make a few loaves of bread. Last of all come the geese, who still continue to pick up a few grains scattered here and there among the stubble, and waddle home in the evening, poor things, cackling with joy because of their success." But the history of science shows that Dr. Barclay's reapers, gleaners and geese do not belong to separate epochs. They are contemporaneous. The reaping, gleaning and cackling go on as a rule in the same field, all at one time, in a grand comic medley of sounds. It is certain that anatomists had not so nearly exhausted their field one hundred years ago as Dr. Barclay believed that they had.

We are told that, about 1878, the president of a certain chemical society informed his hearers in an annual address that the age of discovery in chemistry was closed, and that henceforth we had better devote ourselves to a thorough classification of chemical phenomena. But at that very time Crookes was experimenting in England on high vacua, and the year following he electrified the British Association by his brilliant experiments on "radiant matter." Then came the Lenard rays and in 1895 the Roentgen rays, in 1896 the Becquerel rays and in 1899 radium, with its mysterious radiation. This was followed by the report that probably all matter is slightly radio-active. The study of these phenomena has shaken the old atomic theory, and calls for a reexamination of the principle of the conservation of energy and of matter. The earthquake in San Francisco did not shake buildings so violently as did these new facts shake the great edifice of physical science. The principle of the constancy of matter was called in question in an experiment of Kaufmann on particles shot off from radium. This experiment is hard to interpret, but I am not aware that J. J. Thomson, or Rutherford, or Soddy, or Boltwood, is denying the indestructibility of matter. One French experimentalist, however, LeBon, has advanced the new theory of the destructibility of matter to explain the new phenomena. He advances his new theory as a demonstrated fact, and assumes to speak ex cathedra, when others observe extreme caution. Were he advancing the destructibility of matter merely as a working hypothesis, few could complain; but he puts it forward as a firmly rooted fact.