phosphorus may equally well take place in the case of all those bodies which gain weight on combustion or calcination. I am persuaded that the gain in weight of the metallic calces is owing to the same cause.' Lavoisier followed up this work by the calcination of tin in 1774, and in the same year-after Priestley's discovery of "pure dephlogisticated air"-by the oxidation of mercury. In 1777, Lavoisier stated: that in all cases of combustion heat and light are evolved; that bodies burn only in oxygen (or air éminement pur, as he at that time called it); that oxygen is used up by the combustion, and the gain in weight of the substance burned is equal to the loss of weight sustained by the air.

The differentiation of terms and concepts is so necessary an accompaniment of the advance of science that no collection of examples can be regarded as adequate or as even fairly representative. Though Lavoisier in 1777 succeeded in giving to the concept "combustion" a much more clearly defined meaning than had attached to the "fire" of the ancient philosophers or the "flame" of Francis Bacon, in 1789 he still included "caloric" and "light" in his table of elements. In spite of the definition by Robert Boyle of the concept "element," and the attempt of Newton to determine the meaning of "atom," these ideas, inherited from the remote past, were at the close of the eighteenth century about to enter on a new series of transformations. In the seventeenth century Boyle's contemporary, John Ray, ascribed to the term "species" a definite, if not a final, significance, and Sydenham, seeking to establish by clinical observation distinct species of disease, succeeded in differentiating measles from smallpox, in defining chorea, in modifying the significance of the term "hysteria," etc. Progress in science may involve lessening or increasing the extension of a familiar term, determining anew the distinction between familiar terms, and introducing new clearly defined terms. Pasteur's studies in molecular asymmetry involved a reconsideration of the terms "tartrate" and "racemate" and a delimitation of the concepts which each of these terms expressed. An advantage is gained by substituting the unfamiliar "neurasthenia" for the familiar "nervousness," partly because the new term is unambiguous and partly because it is devoid of every popular connotation. In fact, our scientific terminology has become so much a thing apart that one may overlook the relationship between a common term like "weight" and a more technical term like "mass."

The researches of Schleiden and Schwann, which led up to the statement of the cell theory, were affected and, to some extent, vitiated by traditional conceptions concerning "cellular tissue" and the "cell." Robert Hooke was the first to use the term "cell"

in describing organic structure. He had examined charcoal, cork, and other vegetable tissues under the microscope and described them in 1665 as "all perforated and porous, much like a honeycomb." He could discover no passages between the minute cavities or cells, though he took it for granted that the nutritive juices to be seen in the cells of green vegetables had some means of egress. Hooke's observations were verified by his contemporaries. Grew, in describing the microscopic structure of plants, mentioned the infinite mass of "little cells or bladders" of which certain parts are composed, and Malpighi described the cuticle of the plant stem as consisting of "utricles" arranged horizontally. Caspar Wolff in his doctor's thesis (Theoria Generationis, 1759) reported the observation of cells and "little bubbles" which developed in the homogeneous layers of the embryo. In the works of Bichat, the founder of histology, the term "cellular tissue" was used, as indeed it is to-day, to indicate a certain kind of connective tissue. Treviranus and Link described the cells in vegetable tissues in 1804, the latter maintaining that they are closed vesicles incapable of communicating with each other. Professor John H. Gerould has recently pointed out, in the pages of The Scientific Monthly, the important part taken by Lamarck, Mirbel (the disciple of Caspar Wolff), and others in the development of the conception of the "cell" and of "cellular tissue." After the appearance of Moldenhawer's Contributions to the Anatomy of Plants (1812), which demonstrated that the cavities of vegetable cells are separated from each other by two walls, the attention of observers was diverted from the cell contents to the cell wall. The consequent misconception of the nature of the cell was in part corrected by Robert Brown's discovery of the cell nucleus and by the later discovery of protoplasm. It was before the full significance of the cell contents was realized that the cell theory was conceived by Schleiden and Schwann.

It is evident that advances in scientific thinking imply the use of clear concepts and clear terms. The term "neuron," employed by the early Greeks in the sense of "thong" or "sinew," was applied by the anatomists of the fourth century B. C. to the tendon as well as to the nerve. A considerable treatise alone would suffice to trace its subsequent meanings and those of its derivatives and at the same time to give an account of the investigations that from the time of Herophilus and Erasistratus have contributed to the elucidation of the concepts in question. The terms that represent to-day the so-called chemical elements have no doubt undergone a similar series of transformations in meaning. Distillation, crystallization, and other refining processes had to be brought into play before the concept-the spirit, the essence, the thing in itselfcould be realized.

"WHO'S WHO" AMONG AMERICAN WOMEN

By Professor STEPHEN S. VISHER and

GERTRUDE HOVERSTOCK

INDIANA UNIVERSITY, BLOOMINGTON

ATTELL has made some stimulating statistical studies of the

CAT

2

more eminent scientific men, including the distribution of their birthplaces and of their present residence.1 Some years ago a study of the distribution of the first ten thousand persons in "Who's Who in America" appeared in this journal. The conclusions drawn from these studies, while not to be seriously doubted, are so interesting that it appears worth while to test them by a similar study of a different group of notable peoplethe 1,687 women included in the last edition of "Who's Who in America" (Vol. XI, 1920-21), especially the 1,582 women concerning whom biographical data are given.

The distribution of the place of birth of 1,551 women who gave this information is indicated by districts in Table 1, as is also the ratio between eminent women and the general population of 1880.

TABLE 1

BIRTHPLACES OF WOMEN IN "WHO'S WHO IN AMERICA''

This table reveals the prominent share New England has had in the production of eminent women, and the small share which the southern and western halves of the nation have had. "Who's

1 J. McKeen Cattell: "Families of American Men of Science." The Popular Science Monthly, May, 1915, and THE SCIENTIFIC MONTHLY, October, 1917 (reprinted in "American Men of Science," third edition, 1921). An earlier study based on the starred scientists in the first edition is reprinted in the second edition of "American Men of Science,'' 1910.

2 Scott Nearing: "The Geographical Distribution of American Genius," The Popular Science Monthly, Vol. 85, pp. 189-199, 1914.

Who in America" is published in Chicago and is edited by an Ohioan.

Of scarcely less interest than the variation among the districts is the variation among the individual states in the number of famous women they have produced. Table two shows for each of the leading six states the number and proportion of eminent

Table three gives the number of eminent women born in each state and the number now living there.

This table indicates that Colorado, Wyoming and Arizona, having a population of 260,000 in 1880, produced no women who have been included in this issue of "Who's Who in America." Furthermore, Idaho, South Dakota, New Mexico and Oklahoma, having a total population of 451,000 in 1880, have each produced only one. Thus these seven states with a population in 1880 of 712,000 are represented in "Who's Who" by only four women. On the other hand, New England, which had a scarcely larger population in 1880, contributed 333 eminent women. Similarly, the Southern States, with an 1880 population somewhat greater than that of New England and the Middle Atlantic States combined, produced only 99 famous women in contrast with 844 from these northern states. Not only were few eminent women born in the South about 1880, but still fewer now reside there, 63 vs. 99. The North Atlantic and New England States have attracted many notable women with the result that 1,148 of the 1,687 women listed now live there. In other words, these states produced 54.5 per cent. of the eminent women, but now have 68 per cent. of the nation's total.

This great centralization of production of famous women and of their present distribution may be due to the following in