AMERICAN MEN OF SCIENCE 



565 



with their dominant importance. Science 

 has, indeed, already profoundly altered not 

 only the material conditions of life but also 

 social relations and mental contents and atti- 

 tudes. The conditions of heredity and cir- 

 cumstance which determine the whole course 

 of life are subject to its control. We need 

 only to obtain the knowledge and to apply it. 

 If an improvement of ten per cent, in the 

 cereal crop will yield a billion dollars a year, 

 in what terms of money should an increase of 

 ten per cent, in the annual output of science 

 be stated? 



The application of scientific methods to the 

 advancement of science is in one sense the be- 

 ginning of science and in another one of its 

 latest undertakings. We are at present al- 

 most wantonly ignorant and careless in regard 

 to the conditions which favor or hinder scien- 

 tific work. We do not know whether progress 

 is in the main due to a large number of faith- 

 ful workers or to the genius of a few. We do 

 not know to what extent it may be possible to 

 advance science by increasing the number of 

 scientific positions or how far such an increase 

 might be expected to add to the number of 

 men of genius. We do not know to what ex- 

 tent increased salaries, better facilities and 

 greater leisure would favor the quantity and 

 quality of our work. We do not know to 

 what extent non-rational sanctions, such as 

 reputation, offices, titles, degrees, prizes, 

 membership in exclusive societies and the like 

 are effective. We do not know whether it is 

 wise to combine teaching with research or ap- 

 plied with pure science. We do not know 

 whether it is better for the professor and in- 

 vestigator to have a moderate salary, a life 

 position and a pension, or to engage in severe 

 competition for large prizes; whether obedi- 

 ence and discipline should be prescribed or 

 the largest individual liberty allowed. We 

 know but little as to the kind of education, 

 methods of work and mode of life, which are 

 most favorable to scientific productivity. In 

 the face of endless problems of this character 

 we are as empirical in our methods as the 

 doctor of physic a hundred years ago or the 



agricultural laborer to-day. It is surely time 

 for scientific men to apply scientific methods 

 to determine the circumstances that promote 

 or hinder the advancement of science. We 

 should begin where and when we can; even 

 though the results of the first efforts may ap- 

 pear somewhat trivial, we may proceed in the 

 confident belief that in the end the advance- 

 ment of science will become an applied sci- 

 ence. 



In a series of three articles published in the 

 numbers of SCIENCE for November 23 and 30 

 and December 7, 1906, the writer described the 

 methods which he used to select a group of a 

 thousand leading American men of science, 

 the application of these methods to the meas- 

 urement of scientific merit, and the origin 

 and distribution of the group. About seven 

 years having elapsed since the selection of the 

 group treated in these articles and a second 

 edition of the " Biographical Directory of 

 American Men of Science " being in prepara- 

 tion, it seemed desirable to repeat the process 

 of determining the thousand leading scien- 

 tific men in the United States. It is worth 

 while to learn what changes have taken place 

 in the composition of this group and in the 

 distribution of the scientific men among vari- 

 ous institutions and in different parts of the 

 country. A list of scientific men as nearly 

 contemporary as might be was also wanted 

 for some further studies of the conditions of 

 heredity and environment which are favorable 

 to scientific productivity. 



The methods used to select the group of a 

 thousand leading men of science were sub- 

 stantially the same as before and need not be 

 redescribed in detail. The scientific men were 

 distributed among twelve sciences as previ- 

 ously. It was intended that the number in 

 each science should be proportional to the 

 total number of investigators in that science, 

 and it was as nearly so as is needful for the 

 purpose in view. The distribution was as fol- 

 lows: Chemistry, 175; physics, 150; zoology, 

 150; botany, 100; geology, 100; mathematics, 

 80; pathology, 60; astronomy, 50; psychology, 



