takes place in an iron wire immersed in a strongly oxidizing solution like concentrated nitric acid, and is similarly associated with a return of the original sensitive or quasi-irritable properties of the film; this recovery is also attended with a certain delay, analogous to the refractory period of the protoplasmic system. In this automatic return of passivity both the general oxidizing action of the solution and the electrochemical oxidizing influence at the local anodic regions of the metallic surface are factors. Iron wires which have previously been rendered passive will frequently retain their passivity for an indefinite time, if left undisturbed, in solutions whose oxidizing powers are insufficient to impart passivity to already active wires. This is the case, for example, in solutions of nitric acid of less than 1.2 s.g.; in such solutions passivity remains unaltered for an indefinite time, provided the continuity of the surface-film is not interrupted (by mechanical or other means) over a sufficiently great area. But activity, once it is established, is permanent and the metal dissolves in the acid. As a rule, extensive scraping or vigorous jarring is required to activate mechanically a passive iron wire immersed in 1.2 HNO,, although different specimens of iron vary in sensitivity. Apparently if the total area of metallic surface which is thus freed from film and exposed to the direct action of the acid is less than a certain critical minimum, the local anodic action quickly reforms the film, and the wire as a whole continues to exhibit passivity. Hence a single scratch with a glass rod may be ineffective, while if several scratches are made simultaneously or close together the total or summated effect may be sufficient for activation. This behavior throws light upon the general nature of summationeffects in film-covered systems of this class, which include living protoplasm as well as passive iron. Destruction of a sufficient area of surface-film is followed by a rapidly propagated wave of activity which destroys the whole film and renders the whole metal active. Thus the physiological distinction between the "local change" and the "propagated disturbance" in irritable tissues, familiar to physiol ogists from the work of Keith Lucas and others, is exemplified in the behavior of such wires. Any alteration of the film affecting less than a certain critical area fails to propagate itself and involve the whole surface. Apactive area must exceed a parently the ratio passive area certain critical minimum if the activating effect is to gain the predominance and involve the whole surface of the metal; otherwise the entire surface resumes the passive state. Local conditions of either passivity or activity are equally capable of spreading; and the final state of the system as a whole depends upon whether the one or the other condition gains the upper hand. The tendency to revert to passivity after local disturbance varies in different metals and in different specimens of the same metal; for example, in nickel (in 1.2 HNO3) it is much greater than in iron. Hence the local state of the surface at any time is determined by the relative intensity of the two opposed processes, one of which tends to form and the other to destroy the surfacefilm. A similar statement holds true of the protoplasmic systems; in the maintenance of any living structure constructive or anabolic" processes are continually at work, which compensate or offset the continually acting destructive processes; this applies to the surface-film as well as to other protoplasmic structures. Another simple observation, continually repeated in these experiments, indicates still further the active or self-regulating character of the process by which the surface-film of passive iron is preserved intact in an oxidizing solution (e. g., 1.20 HNO3) in spite of minor disturbances or local alterations in the film. All solutions of chlorides rapidly destroy passivity, at a rate which is approximately proportional to the concentration of the Cl-ions; usually in the wires used in the following experiments an exposure of 8 or 10 seconds to m/1200 NaCl or KCl is required to render a passive wire reactive to 1.20 HNO3. When, however, such a wire is exposed to the salt solution for less than this critical period, e. g., for 6 seconds, and is then dipped momentarily in 1.20 HNO,, washed in distilled water, and again placed in the salt solution, it is found that the time now required for activation is not shorter but is essentially the same as before, i. e., 8 to 10 seconds. Evidently the brief exposure to the acid has restored the partly altered film to its original condition. But if the process of alteration in salt solution is allowed to pass the critical stage (with, e. g., 10 seconds exposure) before transfer to the acid, the latter has no passivating action, and the wire continues to react until completely dissolved. This observation shows that the progressive modification which the film undergoes in the salt solution is of a kind which is rapidly and completely reversible if the metal is returned to the acid before a certain critical stage is reached; but after this stage is once passed the whole film breaks down when the wire is replaced in acid and the iron is no longer protected against solution. This behavior resembles that of living cells after transfer from a balanced salt-solution like sea water to a toxic solution like pure m/2 NaCl, as shown (e. g.) in Osterhout's experiments with Laminaria; the cells undergo a progressively injurious modification associated with an alteration in the properties of the plasmamembranes, shown by increasing permeability; this change may be reversed by transfer to the original medium before, but not after, the modification has reached a certain critical stage. Thus the characteristic power, normally possessed by the living plasma-membrane, of preserving intact its continuity and semipermeability is simulated in a general manner by the behavior of the surface-film of passive iron in dilute nitric acid. The action of salt-solutions upon those surface-films (influence of nature and concentration of salts, relative rates of action of different salts, antagonisms) will be described more fully in the second part of this article. RALPH S. LILLIE SOCIETIES AND ACADEMIES THE NORTH CAROLINA ACADEMY OF SCIENCE THE annual meeting of the North Carolina Academy of Science was held at Trinity College, Durham, on May 2 and 3. The presidential address was given by Dr. E. W. Gudger on "On an extraordinary method of fishing the use of remora for catching fish and turtles.'' The following papers were presented: Undamped electrical oscillations: C. W. EDWARDS. A portable printing outfit for the ecologist: Z. P. METCALF. Sanitation in the south: THORNDIKE SAVILLE. Some generic distinctions in sponges: H. V. WIL SON. A magnetic paradox: F. N. EDGERTON, JR. Vegetation in the closing of ponds with special ref erence to the Kamaplain ponds of Wexford county, Michigan: COLLIER COBB and H. D. HOUSE. Preliminary studies of the reproduction rate of Copepoda: FANNIE É. VANN. Deposits of volcanic ash: JOHN E. SMITH (by title). Asymmetry in the formation of the nervous system in the frog embryo: BLACKWELL MARKHAM. Recent mosquito control work in North Carolina: R. W. LEIBY. Reptilian folklore: C. S. BRIMLEY. New or little known diatoms from Beaufort, North Carolina: J. J. WOLFE. Some notes on Protozoa: (a) Occurrence of Tintinnus serratus Kofoid in Chesapeake Bay. (b) Arcella excavata nov. sp.: BERT CUNNINGHAM. The ovary of the Gaff-topsail catfish, Felichthys felis: E. W. GUDGER. The seventeen-year locust in North Carolina in 1917: Z. P. METCALF. Our rats, mice and shrews: C. S. BRIMLEY. The felsites of Mount Collier: JOHN E. SMITH (by title). The inland waterway from Boston to Beaufort: COLLIER COBB. (a) A new parasitic blue-green alga. (b) Comparison of Rhododendron catawbiense with a form occurring at Chapel Hill: W. C. COOKER. Locating invisible objects: C. C. HATLEY. SCIENCE A BASIS FOR RECONSTRUCTING THE pages of a leading English botanical journal have, for over a year past, in every issue, contained letters and articles discussing botanical reconstruction and the need of it.1 One of the foremost American universities has recently sent out a questionnaire asking for opinions and suggestions bearing on the reconstruction of general biological instruction within the college; and the National Research Council has invited constructive ideas as to what should be the content of an "intensive" course of study. The same topic is being discussed in addresses and magazine articles in America. Davis has recently called attention to the importance of the question in SCIENCE, as has also Peirce, in his recent address before the San Francisco Bay Section of the Western Society of Naturalists.3 But how shall we decide the content of the introductory course? Something more is needed than mere personal opinion based on the peculiar experiences, and idiosyncrasies, and limitations of individuals. The question is larger than the subject of botany, for it includes the broad problems of educational policy and theory. First of all, then, certain basic principles must be formulated and, if possible, agreed upon. It is the aim of this paper to state, and briefly discuss, two or three of these principles: One might think that, after all that has been said and printed on the subject, one need 1"The Reconstruction of Elementary Botanical Teaching," New Phytologist, 16, 241-252, December, 1917; 17, each issue, January-December, 1918. 2 Davis, Bradly Moore, "Botany After the War," SCIENCE, N. S., 48, 514-515, November 22, 1918. 3 Peirce, George J., "What Kinds of Botany Does the World Need Now?" SCIENCE, N. S., 49, 81-84, January 24, 1919. hardly refer to the most fundamental question of all-namely, the purpose of education in general; yet every time the content of the curriculum is discussed, it becomes all too evident that many worthy people either do not keep that question clearly in mind, or else they wholly misconceive it. One can not go into details here the question is too large. At the risk of being trite, it may be categorically asserted that the aim of education is not merely to give information, nor merely to teach somebody how to do something, and especially is the aim of education not confined to preparing young people to get a living, nor (more emphatically) to get a living only by commercial pursuits. This could not be better said than it was by Professor A. Caswell Ellis:4 Certainly they [the laboring classes] must have vocational education to make efficient producers, but they are going to be "producing" only about six or eight hours a day. What preparation is the school to give for the other sixteen or eighteen hours each day and the twenty-four on Sunday? I think it will hardly be extreme to say that this question is the supreme problem of present-day education. As Professor Ellis continues to say: "If we do not show more intelligent recognition of this problem than we have in the past then the production of isms and impossible Bolshevist dreams during the leisure hours may more than offset the material production of the working hours." And even if the individual is not inclined to be an agitator, or a public menace in any way, he has himself to live with sixteen or eighteen hours a day, and he exerts his conscious or unconscious influence on others whether he will or not; and he may become a member of the local government, or a member of the board of education, or, if worse comes to worst, even a school superintendent, having a large voice in the organization of public education. Certainly it ought to be clear that the public school curriculum, and the content of each subject taught should be determined with such eventualities, as well as with vocational needs, in mind. Not to dwell unduly on this first point, let 4 Jour. Nat. Inst. Social Sci., 4, 135, 1918. us very briefly note that public education should always adapt itself to the needs and ideals of the age, seeking at the same time to help mold and formulate them. In what direction, then, let us ask, is social organization now tending? What is the modern spirit? Well, a new spirit and changed ideals have certainly been developing during the past two or three decades. One of the outward expressions of this fact is the reduction of the hours of labor from twelve a day to nine or eight. One of the finest expressions of the new spirit is the address of John D. Rockefeller, Jr., before the War Emergency and Recontruction Conference of the Chamber of Commerce of the United States, at Atlantic City, on December 5, 1918. "Men are rapidly coming to see," said Mr. Rockefeller, "that human life is of infinitely greater value than material wealth;" and "Modern thought is placing less emphasis on material considerations. It is recognizing that the basis of national progress, whether industrial or social, is the health, efficiency, and spiritual development of the people." The fourth article of his proposed industrial creed rightly affirms, "that every man is entitled to an opportunity to earn a living, to fair wages, to reasonable hours of work and proper working conditions, to a decent home, to the opportunity to play, to learn, to worship, and to love, as well as to toil." Every subject in the curriculum, therefore, should, in its introductory course at least, have its content decided with reference to this entire modern ideal. But, unfortunately, proposals are now being made in some quarters to revise the botanical course of study in exactly the opposite direction, evidently with the idea that the chief purpose of studying the subject is preparation for a vocation. I would not, for a moment, wish to appear to be losing sight of the fact that there is a vocation of botanist, and many vocations depending, in whole or in part, upon a knowledge of botany. What I am objecting to is the tendency to lose sight of every other consideration, and to commercialize or vocationalize every subject from the introductory course to the doctorate thesis. The committee appointed some months ago in England by Mr. Asquith said, none too emphatically: "Practical education is the only foundation on which idealistic achievements can be raised; to neglect the practical ends of education is foolishness; but to recognize no other is to degrade humanity." In this connection I would like to urge the desirability of offering, in all of our colleges and universities, "cultural courses in the various sciences, consisting only of illustrated lectures made as fascinating and broadening as possible, and supplemented by assigned readings and discussions. The aim of such courses should be to give those who have not yet decided upon their life work as well as those who have, a scholarly survey of the aims, problems, methods, history, and results of the given science, and a clear idea of its significance for daily life-personal and social. Such courses would have substantial benefits alike for those who took them and for those who gave them, and would undoubtedly be the means of revealing to many the direction in which their life work lies. In the second place we should never forget that one of the important aims of education is to enable the individual to find himself; and especially important is it to keep this in mind in deciding on the content of introductory courses. They should be made as informing and broadening as possible. The student should be made to feel that the given subject touches his life, and to what extent— that a knowledge of it is of personal significance to him, that it is replete with fascinating unsolved problems, in the solution of some of which he may find his obvious opportunity for a contented and useful life. And finally we should always remember that the introductory courses should almost never be planned on the sole supposition that the student is to take more advanced courses, but in full recognition of the fact that the first Report of the Committee to inquire into the position occupied by the study of modern languages, etc. Issued as a White Book. Quoted from the New Statesman (London) by World Wide (Montreal), August 17, 1918. course may be the only one many students will ever take of any particular subject. With this in mind the course should be made as rich as may be in informational, cultural, educational values. If regard is had for these requirements the course ought to prove entirely satisfactory as a preparation for more advanced study. From this point of view, undue emphasis should not be placed on details of technique, or minor matters of mere information, but on the broad generalizations that appeal to the imagination and challenge one's admiration, enlarge one's vision, and stimulate and illuminate one's thinking. Some glimpse should be given into the history of the subject, some acquaintance, however slight, with the great names of its makers; and especially should there be some introduction to the unsolved problems that continually challenge and beckon the explorer of the dark continents of knowledge. In brief, the introductory course, that may prove to be the last, should be so planned as to enrich the student's life as much as possible. If that given subject proves to be his main life interest, such a course will also prove to be a satisfactory introduction to more advanced work. At this particular time there seems to be a movement for "intensive" short courses of study. This is no doubt a direct outcome from the program of the Students' Army Training Corps, when intensive short courses were made necessary by the exigencies of war. Osborn has called attention to the fact that the view is likely to obtain with the administrators of student curricula that, if intensive courses are effective "in an emergency," they might well be useful at other times. The danger here is in losing sight of why intensive courses are "effective in an emergency." The need in an emergency is action-accomplishment. What is demanded is the possession of knowledge that may be quickly applied to meet the pressing need. To live a life of culture-of deep insight, broad 6 Osborn, Herbert, "Zoological Aims and Opportunities," SCIENCE, N. S., 49, 109, January 31, 1919. |