duced hybrid plants. We have thus arrived at clear criteria for hybridism based on the study of the cytological changes in the dividing mother cells of the reproductive elements. It is an interesting fact that these abnormalities are not found in the vegetative or somatic divisions. This no doubt is the reason that their importance in the study of the origin of species has received so late a recognition.

Rosenberg quickly noted that similar peculiarities appeared in the reproductive divisions of the very variable dog-rose of Europe, Rosa canina, and one of his students, Taeckholm, carried out observations on European roses in general with similar results. Simultaneously Blackburn and Harrison made parallel observations on the roses of England. Abnormal reproductive divisions in the roses of Europe, western Asia and northern Africa, united with a large degree of variability and likewise marked sterility, make it more than probable that the multiplication of species of roses in the European area is the result of hybridism. Our eastern American roses are of pure race, but in America another huge and variable rosaceous genus, Crataegus, the hawthorns, has been shown by investigations carried on by Dr. A. E. Longley to be largely of hybrid origin. Hybridism in fact is extremely common in the larger genera of the Rosaceae. Not only have the criteria of hybridism (sterility and abnormality in the reproductive divisions) been clearly discerned in many of the Rosaceae, but although the field is as yet new and comparatively unworked, numerous examples have already presented themselves in the Compositae, Myrtaceae, Betulaceae, Fagaceae, Proteaceae, Gramineae, etc., etc. We are in fact already in the position to state with confidence that hybridism has played a large rôle in the multiplication of species among the higher and even the lower plants.

We may at this stage consider, so far as plants are concerned at any rate, the cause of the high variability, noted by Darwin, as an outstanding feature of larger groups. It receives its natural explanation as the result of hybridization in nature, since precisely in these very large groups we find sterility, abnormalities in reproductive divisions and in the production of pollen. Further the conclusion recently set forth by Osborn and cited in an earlier paragraph, that isolated species are constant and not connected by intermediates with other isolated species, is attributable to the absence of the possibility of hybridization. On the other hand, where species grow in proximity, they may naturally be connected with every possible sort of hybrid intergradation.

ANIMALS

We may now turn our attention to the animal side. Here known hybrids are infinitely less common than

is the case with plants. I have chosen the Orthoptera for investigation in this respect. This group is particularly favorable by reason not only of its great extent but also on account of the large size of the reproductive cells, which make them suitable for cytological study. The grasshoppers and locusts belonging to this group are distinguished for their numerous and extremely variable species. It is in fact said that there are as many as thirty thousand species of grasshoppers in the larger sense in North America. and hundreds of new species are described every year. In the reproduction of animals the sperms are produced in fours precisely as are the corresponding pollen grains on the plant side. If one examines microscopically the reproductive gland or testis of almost any grasshopper, locust or cricket, one usually finds present huge quantities of sterile sperms, particularly in the earlier stages of activity of the gland. These abortive sperms naturally suggest a comparison with the correspondingly sterile pollen of the hybrid Drosera and that of numerous species of roses, hawthorns, etc., etc. The earlier formed sperms present the same abnormalities as present themselves in the divisions of hybrid plants. It is at once reasonable and scientific to suppose that the huge multiplication of species in certain Orthoptera is like the similar multiplication of species in large groups of plants, due to hybridism. The peculiarities in relation to sterility and abnormal conduct of the chromosomes in the reproductive divisions are not confined to the Orthoptera, but have been unwittingly described in large and variable genera of snails, butterflies, moths, spiders, flies (Diptera), etc. I assume accordingly that the variability found in the large groups of animals, since it is accompanied by the same cytological abnormalities and the same sterility as is found in known and suspected hybrid plants, is likewise an indication of the rôle played by hybridism in the formation of new species. Hybridization appears also to be responsible for the phenomenon known as parthenogenesis.

II

PARTHENOGENESIS

An interesting abnormality in reproduction is presented by many plants and animals. Normally the formation of offspring depends on the fertilization of the egg of the female by the sperm of the male. In a number of cases, however, eggs are able to produce new individuals without previous fertilization This phenomenon is known as parthenogenesis. It is well illustrated among plants by the common dandelion. In this species, the pollen grains are for the most part abortive and even where they reach a certain size lack the two nuclei which are present in

normal pollen grains of other flowering plants. It is possible to remove entirely the anthers or pollenproducing organs in the young flower by excision with a sharp razor, and with them the stigmata or receptive surfaces connected with the ovaries. The flowers under these circumstances set seed precisely as if nothing had happened. My observations on the pollen mother cells reveal the fact that their divisions show all the cytological peculiarities of hybrids. There are, for example, both bivalent and univalent chromosomes, which lag after the hybrid manner in division. Further the lagging of the chromosomes is responsible for the formation of small and supernumerary nuclei, which give rise to small abortive pollen grains. Finally, the pollen as a whole is completely sterile and consequently incapable of effecting fertilization. Similar observations have been made on the cudweeds (Antennaria), the hawkweeds (Hieraeium), the ladymantles (Alchemilla), etc., etc. I have observed an interesting case in the common broomrape, a parasite, known as Orobanche uniflora, which is at the same time parthenogenetic and presents all the peculiarities of known hybrids. On the basis of detailed agreement in essential features with known hybrids, there seems to be no reasonable doubt that parthenogenesis in plants may be a favorable variation following previous hybridization. This view has been ably put forward by Ernst before the cytological peculiarities of hybrids were as clearly formulated and understood as they are at the present time. Winkler's criticisms, which represent the narrowness of view which so often characterizes the pure experimentalist, are accordingly of slight importance.

The cytological evidence seems clearly to indicate that parthenogenesis is the result of previous hybridization in plants and it is of interest in the present connection to discover if the evidence points towards a similar conclusion in animals. One of the most striking cases of parthenogenesis is presented by the green-flies or aphids as well as related parasitic insects. My own studies show here the same peculiarities as in parthenogenetic and hybrid plants. There are univalent lagging chromosomes, which often form supernumerary nuclei and a very large amount of sterility is presented by the sperms, which are frequently highly abnormal. The univalent laggards have been noted by the zoologists, but under a misapprehension as to their significance have been called "sex chromosomes." It is, however, in view of the whole situation, quite impossible to put this interpretation upon them. The described cytological conditions in connection with parthenogenesis in ants, bees and wasps, lead to the conclusion that these too, so far as they are parthenogenetic, are of hybrid

origin. A similar statement holds for parthenogenesis in certain parasitic worms.

An interesting case is presented by the grouselocust, Apotettix Eurycephalus, in which Nabours has recently described parthenogenesis. On request he has kindly furnished me with suitable material and I have been able to observe not only a high degree of lagging in the chromosomes, but also a marked degree of sterility. It is of interest in this connection to note that Harrison had already suggested on the basis of Nabours's work that the species under consideration is of hybrid origin.

MUTATION

A great deal of attention has been focussed in recent years on the so-called phenomenon of mutation or saltatory origin of species. Stock illustrations of this condition are the evening primrose (Oenothera), Drosophila melanogaster and the Boston fern. There is little doubt both from the experimental and morphological standpoints that most of the species of Oenothera are of hybrid origin. Their extreme variability in many instances, their usually high degree of sterility and the cytological peculiarities, particularly of the more sterile species or subspecies, clearly testify to a heterozygous origin. The Boston fern, which originated some time ago in a greenhouse in Cambridge, has been investigated in my laboratory and it shows both the extreme sterility and the special cytological characteristics of a hybrid. Elsewhere the present author has shown that Drosophila melanogaster is, on the basis of its extreme variability and its cytological abnormalities, of hybrid origin.

There can scarcely be any reasonable doubt that so-called mutation in general is associated with previous hybridization. The so-called mutating forms present usually the high variability, the sterility and the cytological peculiarities of known hybrids. Further, Tower's experimentally produced hybrids of the potato-beetle are described by him as showing subsequent mutations.

GENERAL CONCLUSIONS

It will be obvious to the reader who has followed the data and descriptions of the preceding paragraphs that striking abnormalities are frequently found in the divisions of the reproductive cells of both plants and animals, where these are highly variable or belong to large groups or genera. These peculiarities present an inescapable resemblance to the conditions found in known hybrids. It follows that the high degree of variability noted long ago by Darwin, in large groups of plants and animals,

It seems clear that the phenomenon of parthenogenesis in plants and animals is likewise to be explained as a successful result of previous hybridization. Since the general sequel of hybridization is sterility, the only outlook for the offspring of a hybrid union is either the development of improved sexual fertility or the appearance of parthenogenesis.

The peculiarities of so-called mutating forms find their rational elucidation in the study of the phenomena, variational and cytological, of known hybrids. It accordingly follows that mutation, so far as it is a real cause of the origin of species, is merely the appearance of more or less constant offspring, following a previous hybrid union.

In our study of the origin of species we have now apparently, after many years of comparatively ineffectual effort, reached a point of view which will enable us to explain some at least of the fundamental causes of variation, fluctuating or fixed. One-sided attack has been shown to be futile. The great merit of Darwin's work is its many-sidedness. To-day, too, it seems clear that for permanently valid results in biology, structural and experimental work must go hand in hand. Moreover, observations in the field and observations in the laboratory must supplement one another for the most fruitful results.

HARVARD UNIVERSITY

EDWARD C. JEFFREY

SCIENCE AS CULTURE

ONLY about ten per cent. of the undergraduates who, since the war, have taken general chemistry at ten leading colleges and universities1 pursue further chemical courses. But one student in forty-five does postgraduate work in chemistry.

It would require an exhaustive study of registrar's records and post-collegiate careers to determine how many graduates make any direct or indirect use of chemistry in their life work; but this is not necessary to confirm the common observation that they would be only a small fraction of those who take an introductory course in the science.

What, then, should be the purpose of such a course? "To state the laws and define the conceptions of the science in terms of experimental facts" is the

1 Harvard, Yale, Princeton, Williams, Virginia, Ohio State, Michigan, Illinois, Northwestern and California. The records are not satisfactorily complete for this purpose; but the data are sufficient to assure representative results. Technical schools and universities where engi neering courses are notably stressed were purposely omitted.

2 Alexander Smith, "Inorganic Chemistry."

of twoscore college texts. Hundreds of courses, described in the curriculum as "Chemistry I-general chemistry, lectures and laboratory work," are given each year, more or less successfully attaining this object. From the student's point of view, a firm foundation of chemical science with a year's training in scientific methods of work and scientific habits of thought is shooting wide of the mark. Judged by standards of interest and utility for the majority, it would be more profitable to teach ice-skating to the Hottentots.

Those who have given thought to this subject will not even debate these facts. It is conceded that pandemic chemistry, suggested by Bancroft, serves the needs of the average student better by treating chemistry as a cultural subject. Such a course-the pioneer, I believe was introduced tentatively at Marshall College under Professor Phelps two years ago, and at Harvard, Yale and Cornell, possibly elsewhere, too, similar experiments are being made. The subject is in the air-very much in the air-but the thought seems to be condensing that two distinct Chemistry I courses, professional and pandemic, must of necessity be developed best to serve the different needs of students who plan to follow medicine, engineering, or one of the natural sciences and those who will make no professional use of chemistry.

This thought I would examine in its nascent state. It will be easier to analyze before it crystallizes.

For this task I have no professional equipment. However, during the better part of ten years, I have served as liaison officer between the three groups who, after all, are most concerned with the practical results of chemical education; the industrial chemists, the chemical manufacturers and the industrial consumer of chemicals. From this coign of vantage it is my business to survey the chemical fields without becoming lost in the towering forests of chemical theory or being bemired in the swamps of chemical commercialism. This point of view is certainly interesting and perhaps helpful.

The time when a knowledge of the Greek and Roman classics was the hallmark of an educated man has past. To-day, even their cultural value is fast diminishing. To know Eros is nowadays not so important as to know what Freud believes about love. The fire Prometheus stole is less use to us than the energy generated by photosynthesis. Phoebus's chariot has become an internal combustion engine: radio replaces Mercury; the metamorphosis of eellulose into rayon, lacquers, celluloid, artificial leather. explosives and what not transcends the myths told

3 Walter D. Bancroft, J. Chem. Educat., 3, 396 (1926).

by Ovid. Chemistry, physics and biology are to-day not only "a systematized and co-ordinated body of facts," they are also the tools and the toys of the man on the street. They are at once the subject of erudite monographs by specialists and of common gossip around the tea table. Their laws govern the operation of our factories; their principles are applied in the kitchen; their technical terms have become newspaper jargon. In the marketplace or by his own. fireside a man is deaf, dumb and blind without at least a working knowledge of the sciences. They are, as Br'er Rabbit said, "de mos' kulturines' t'ing in de world."

The case for chemistry as culture is easily proved; but what of the student who intends to use chemistry in a scientific or engineering career? Should he have, as it were, a professional foundation in chemistry substantial along the lines of the present courses in Chemistry I? Or would he profit more by an historical and philosophical introduction to the science which would make clear its relationships to all human knowledge and emphasize the important rôle chemistry plays in art, agriculture and especially in modern industry.

In the first place, not one college student in a hundred has any clear, predetermined plan for his life's work. He has no notion whether he will become a chemist or a chiropodist. Too often chance makes this most important decision for him. So often, in fact, that it prompts us to question the present methods of teaching the sciences. When chemistry is presented to the student as a coordinated body of scientific knowledge, as in the course in general chemistry, it can not but appear so complete, so closely knit that he forms no conception of its gradual development in the service of mankind. Because he knows nothing of the long series of lucky accidents, of bold hypotheses, of painstaking studies, that have gradually built up this hard-won knowledge of ours, he fails utterly to comprehend the fundamental sequence of practical application, theory and established scientific fact. Accordingly, he does not put chemistry in its proper relationships with the other sciences, and he can not appreciate its importatnce in the development of our modern industrial civilization. In his general chemistry course he fits together, as in a jigsaw puzzle, a jumble of laws and formulas; but he can not place them in the broader picture of human experience and everyday existence. The result is that he lashes his memory while, too often, his interest lags. The pathetic enthusiasm roused, among both undergraduates and postgraduate students, when I have lectured to them on the commercial organization and economic functions of the chemical industry

show how stimulating is a tangible contact with these workaday realities.

In the second place, there are all the obvious dangers of early specialization. Certain swift-moving, far-reaching changes within the growing chemical industry, which will surely be reflected in chemical science, make these dangers, at this time, particularly grave.

During the last three decades of the nineteentth century the spirit of pure science surged strong through every branch of chemistry. This was no altruistic ideal: it was an inspiration as vivid and forceful as medieval religion. Facts, new facts, more facts were greedily sought. Inductive reasoning was so lauded and philosophical theorizing so damned that many good chemists actually believed that any chemical problem might be solved merely by observing with sufficient accuracy a sufficient number of chemical reactions. Chemistry was not the only science which suffered from overdoses of unadulterated Baconism, and there were even certain compensating advantages. A splendid treasure house of recorded analysis and synthesis was built, although much of all this good work was scientific only in its amazing technical precision. This laboratory dexterity-truly more an art than a science-was a curious, but very useful fruit of that era of inductive science.

That treasure house of chemical facts has been drawn upon heavily by the great chemical industry which, thanks to that technical skill, has been developed during the past forty years. Chemical processes have multiplied throughout all industries, and the consumption of chemicals vastly increased. Like a rolling snowball, every new commercial application of chemistry has brought with it other processes and new products. The coal-tar dyes, as a familiar example, have helped to revolutionize the bleaching of textiles and the tanning of leathers. All this chemicoindustrial activity created an economic demand for chemically trained men, a demand our universities and technical schools have been striving to fill with that exotic hybrid, the chemical engineer. The whole spirit of chemical education has been so changed that pure science has become a pale and impractical ideal; courses must be practical; and research, subsidized by industry, is scientific only in the journalistic sense of that much overworked adjective.

In the meantime the chemical industry has gone forward by leaps and bounds. Vigorously stimulated by the war, spurred on by the keen competition resulting from over-production; ably assisted by the world's best chemical brains, it not only dominates, it is even beginning to lead, chemical science. Certainly, our industrial application of both catalytic

action and bacterial fermentation is fast outstripping our knowledge of the chemistry involved. While in the past, great chemical discoveries have been personal achievements, to-day they are the carefully plotted results of directed, organized staff research. Formerly, gifted chemists of rare vision and patience, aided by a faithful student or two, have hunted down chemical secrets. Now, corps of chemists, in elaborate laboratories, fitted with every modern appliance and reinforced by libraries stored with the accumulated chemical experience of the past, are besieging chemical problems. These research armies are made up of specialists, each working on some particular phase or part of a general problem which he often but dimly apprehends. Need one press further the dangers of too early specialization on the part of professional students of chemistry?

These dangers are obvious even to our industrialists who lead a movement to foster work in pure science. The fountainheads of our scientific knowledge must be cleansed and revivified. This requires men armed for inductive reasoning with all the chemical facts we have accumulated and all the chemical technique we have acquired. But, above all else, they must be men of courage and imagination who will throw into the chaos of the unknown the grappling irons of deductive theory.

Not only for training such scientists, but also for attracting men of the requisite bold devotion to the science, I submit that a foundation of chemical history and the philosophy of chemistry is best. Such a course, while admirably fitted to the needs of the average student, would be no sinecure. In presenting chemistry historically, from the caveman's discovery of fire, of tanning, of ore smelting to the isolation of Illium and the perfection of the Mont Cenis process of ammonia synthesis, showing how empirical application preceded scientific knowledge and tracing out chemical theory checked by experiment, such a course in pandemic chemistry would cover all the ground of the present Chemistry I. Thus, even for the professional student, little time would be lost. Plainly he would then begin professional study with an understanding of chemistry's true and proper place and an appreciation of the nature of chemical problems that would be invaluable in coordinating his work and rationalizing his generalizations.

NEW YORK, N. Y.

WILLIAMS HAYNES

SCIENTIFIC EVENTS

THE PUTNAM BAFFIN ISLAND
EXPEDITION

SAILING under the auspices of the American Geographical Society, the Museum of the American In

dian, Heye Foundation, the American Museum of Natural History and the Buffalo Society of Natural Sciences, George Palmer Putnam, publisher and explorer, will lead this summer another expedition to the Arctic Circle.

Last summer Mr. Putnam headed the American Museum Greenland Expedition to North Greenland regions and brought back extensive zoological collections for the museum. This year's expedition will be known as the Putnam Baffin Island Expedition. Mr. Putnam expects to sail from New York in June. This trip, like the one last summer, will be made on Captain Robert A. Bartlett's two-masted schooner Morrissey.

The probable route of the expedition, subject to seasonal ice conditions, will be westerly through Hudson Strait and thence north into the Fox Basin district, which is less known than any other similar area on the North American continent. Some of it, so far as mapping is concerned, has remained virtually untouched since the original visit of Luke Fox in 1631. Expeditions into the interior of Baffin Island will be attempted.

Professor L. M. Gould, of the department of geology of the University of Michigan, will be in charge of the geographical work. His assistants will be Robert E. Peary, George Baekeland, Wallace R. Hawkins and George Weymouth.

The expedition's anthropological activities will be carried on in behalf of the Museum of the American Indian, Heye Foundation, which will be represented by Donald A. Cadzow. The zoological collecting for the American Museum of Natural History will be done by Fred Limekiller, a member of last year's expedition. Oceanographic work will be conducted for the Buffalo Society of Natural Sciences. Specimens will be collected by plankton nets and dredging.

THE ANNUAL MEETING OF SCIENCE
SERVICE

THE annual meeting of Science Service, Inc., the institution for the popularization of science, was held on April 28 and two new members of the board of trustees were elected. Dr. David White, home seeretary of the National Academy of Sciences, was named by that body as one of its three representatives upon the board, and Marlen E. Pew, editor of the weekly publication, Editor and Publisher, was chosen a representative of the journalistic profession. Trustees who were reelected were: Dr. D. T. MacDougal, director of the Desert Laboratory, Tucson, Ariz., representing the American Association for the Advancement of Science; Dr. C. G. Abbot, acting secretary of the Smithsonian Institution, representing the National Research Council; Thomas L. Sidlo, of Cleveland, Ohio,