108 POPULAR SCIENCE MONTHLY 



details. Some doubtless felt disheartened because of lack of oppor- 

 tunity, 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 con- 

 temporaneous. 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 dis- 

 covery 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 Boentgen 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 ques- 

 tion in an experiment of Kaufmann on particles shot off from radium. 40 

 This experiment is hard to interpret, but I am not aware that J. J. 

 Thomson, or Butherford, or Soddy, or Boltwood, is denying the in- 

 destructibility of matter. One French experimentalist, however, 

 LeBon, 41 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. 



40 See J. J. Thomson, "Conduction of Electricity through Gases," 1903, 

 p. 534. 



"Dr. Gustave Le Bon, "The Evolution of Matter" (translated by F. 

 Legge), 1907, Charles Scribner's Sons. 



