popular slogan, "the cancer cell is the only parasite," was no longer available to obscure research. It seemed that the "virus" of this tumor must be a living thing, but in spite of enormous labors Dr. Rous was unable to see it or to cultivate it.

Dr. Gye, of the National Institute for Medical Research in London, a student of cancer, of serums and of vaccines, for fifteen years, and for the last two or three years intensely interested in the Rous' chicken sarcoma, has been able to cultivate the "virus" and multiply it in test tubes exactly as we do a living thing, and that, too, through a whole series of tubes of fluid media, and from the final tubes (7th to 9th transfer) he has obtained numerous striking infections in chickens (more than 40). His method is to put 0.02 of a cubic millimeter of the virus into 5 cc of his culture medium, incubate it for three days, then transfer a similar quantity of the fluid to a second tube, incubate that for three days, and so on. The final dilution of the original material,

if it were merely a chemical substance, is so great as to be harmless, and the virulence (the active tumor-producing power) in the end term of the series can not be due to a diluted chemical but must be due to a living multiplying organism. Any other explanation is unthinkable. There is, however, no pellicle, precipitate or clouding in these fluid cultures, so far as I could see, nor is anything visible under the highest powers of the microscope; nevertheless, the organism is there, in a particulate form. This Dr. This Dr. Gye has demonstrated by means of the centrifuge. If fluid containing the virus is whirled 9,000 revolutions per minute, and certain other necessary conditions are properly adjusted (I am not at liberty to state what they are), all the virus is thrown down to the bottom of the tube and remains virulent, whereas the previously infectious supernatant fluid has now become harmless as water, but even in the precipitate no organism is to be seen, stained or unstained, by use of the ordinary microscopes. Dr. Gye has also observed another interesting thing, viz., when his cultures become contaminated with cocci and other microorganisms they cease to be virulent. There seems to be an antagonism. He formerly believed malignant tumors non-parasitic, but now he believes very firmly that all or most of them are of parasitic origin. He is full of enthusiasm and believes, as I do, that the solution of the cancer problem is not far off.

2 Allard has shown for tobacco mosaic and Doolittle for cucumber mosaic that the juice is only rarely infectious much beyond dilutions of 1 to 10,000, as Olitsky has also shown, and such dilutions are surpassed in the second tube of Dr. Gye's series, whereas in his seventh tube in series the dilution is in the trillions and in his ninth tube it is in the quadrillions.

It remained for the physicist, Dr. Barnard, a colleague of Dr. Gye, to demonstrate the organism, using special objectives and monochromatic light. I have been in his laboratory and have seen the body dancing about in the culture fluid (rabbit serum) and also mounted slides of it and photomicrographs of it. It is the same type of germ as the pleuropneumonia organism, but smaller. The latter, seen first by a Frenchman, was described as resembling a yeast, but seen by the subdued monochromatic green-band light of a mercury lamp and with Dr. Barnard's objective of 1.3 aperture, with which he can see down to 0.1 μ, it has none of the characters of a yeast or of an ordinary Schizomycete.

The general method of development of these two organisms, as worked out by Dr. Barnard during the last two years, is to begin as small glistening particles (I saw them under a magnification of 1,800 diameters). These apparently swell up into soap-bubblelike, tiny globes, at least all sizes and gradations of

such bodies appear in the fluid. Then, in the surface film, never in the interior, slight thickenings appear, here and there. These thickenings, of which there may be several on a sphere (I saw as many as six or eight on some of the spheres), finally round off, push out into the fluid, remain attached for some time to the periphery of the sphere by a narrow pedicle and then become free, as glistening points, to go through a similar swelling and evolution. I saw nothing resembling a nucleus or a protoplasmic content in any of these bodies.

It would seem to me also from Dr. Gye's work, which is unpublished as yet, that he must have attenuation of the virus in some of his tubes and a vaccine, but we must wait for the completion of his studies to know definitely as to this. I saw nothing in Europe more interesting than his work and that of his colleague. More money is urgently needed there for research assistants, and, in my opinion, it could be nowhere expended more wisely. It should be forthcoming abundantly and at once, while these two remarkable men are living and active.

It seemed to me immediately that this work might also throw light on the origin of some of the mosaic diseases of plants, in the cells of which various peculiar and problematic bodies have been observed. I did not then know of Dr. Olitsky's work at the Rockefeller Institute for Medical Research in New York. His studies (The Jour. of Exp. Medicine, January 1, 1925) seem to demonstrate that in tobacco and tomato mosaic there is also a particulate multiplying organism and not, as Beyerinck suspected, a fluid contagium, whatever that may mean. I was never able to formulate a clear idea as to what Dr. Beyerinck's "contagium vivum fluidum" could be, but always I

believed and said that the virus of tobacco mosaic would surely turn out to be a microorganism. Olitsky has done for the tobacco mosaic exactly what Gye has done for the chicken sarcoma, and the etiology of mosaic diseases is now in a fair way to be resolved into the presence of parasites in the tissues, just as the logic of the phenomena all along required it to be! Probably with Dr. Barnard's apparatus the organism of the tobacco mosaic can be seen and photographed. It would be worth a journey to London to determine this.

I come now to the work of Dr. Ferdinand Blumenthal and his assistants, Dr. Hans Auler and Miss Paula Meyer, in Berlin. Dr. Blumenthal is the director of the cancer laboratory of the great Charity Hospital on Luisen Strasse and the responsible editor of the Zeitschrift für Krebsforschung, the leading cancer journal of the world.

After several years of work they reported that they had been able to obtain from human breast cancers a bacterium in pure culture resembling culturally Bact. tumefaciens, the cause of crowngall in plants, and with this organism had been able to cause malignant transplantable tumors in rats and crowngalls in plants. These statements were so surprising and interesting that I went to Berlin and spent about two weeks in their laboratory at the Charity Hospital in order to see as much as possible of their work and to clear up certain doubts raised by the reading of their papers. I was received very courteously. I asked a great many questions and was shown cultures, slides and inoculated plants and animals. Much of my scepticism disappeared on learning exactly how things were done. It is not always possible for a good experimenter to write up his results in a convincing way. That is a special gift. Some of their statements should have been more explicit. I thought I saw various doubtful things in the papers. I was prepared to believe that the rat tumors were accidents, but after being on the ground the only conclusion I could come to was either that the organism from the human cancer is the cause of the rat tumors or else that they are due to some invisible virus introduced along with the heated oedematous cancerous breast serum which was added to the bacterial culture along with the kieselgur (diatomaceous earth) as a second irritant. As for the plant tumors, the organism PM, which looks much like the crowngall organism on agar streaks, and is said to behave the same serologically (cross agglutination tests in rabbit serum), not only produced good typical looking crowngalls on sunflowers and other plants two years ago, but is still able to do so. I saw them and brought away specimens and also some of the rats and stained sections of the rat tumors. I counted thirty-two metastases in the lungs of one transplant rat inoculated with L, and I

have here a rat inoculated with PM showing five conspicuous secondary tumors.

Hearing that the Berlin experiments had been repeated in the Aktien Gesellschaft Serum Laboratory Dresden, with the same results, and that an address was to be given on the subject before the Dresden Medical Society, I went down there, heard the address, saw the experiments, talked with the experimenter, Dr. Reichert, and with the director of the laboratory, Dr. Behlke, and most of his associate pathologists. They have done two things in Dresden. They have propagated the tumor PM through a long series of rats starting from an implanted rat received from Dr. Blumenthal and they have originated new tumors. I saw a dozen or more of the dissected rats full of secondary tumors. There can be no doubt as to the malignancy of the tumor, and to call it an infectious granuloma does not help matters. It looks to me like a carcinoma. The second thing they have done removes one of my objections to the Berlin work, viz., use of cancer serum as an irritant. Using cultures of PM (obtained it will be remembered two years ago from an inoperable human breast cancer) they have produced in rats two metastasizing, malignant, transplantable tumors without the addition of any cancer serum. These had been carried to the fifth and sixth generation of transplants when I was there early in March. The percentage is low, it is true, two cases only out of fifty rats inoculated (the tumors receded in the others), but then we must remember that the organism is in a strange host, and that rats are often resistant to their own tumors. Up to the time of my visit no efforts had been made in Berlin to obtain by breeding a race of rats more susceptible to the bacterial inoculations, but now they will try to do this, at least they promised to undertake it. Dr. Schmorl, the well-known pathologist, in discussion of the Dresden paper, said the structure of the tumor left him in some doubt. He thought the tumor might be carcinoma because so far it has never been found in the spleen (Miltz), whereas the commonest rat-tumor, the rat-sarcoma, is often found there. The tumor is unlike any other rat tumor I have ever seen. The Dresden tumors are like the Berlin ones, and it seems to me very improbable that they should be, all of them, accidental tumors, and yet all of the same peculiar type. The tumor is a diffuse, rather non-typical looking carcinoma, as if it might be a carcinoma plus a bacterial infection, yet in some of the metastases it is a sarcoma. This is not surprising, however, as often in tar-cancer in mice sarcoma and carcinoma appear in the same animal. Dr. Fibiger, of Copenhagen, showed me two metastatic nodules in the lung of a mouse (almost in the same field of the microscope), one a typical sar

coma and the other an equally typical carcinoma. Polymorphs are numerous, and I think I have made out bacteria in places, but these often occur in rattumor transplants. As I have said, the hypothesis that they are pure accidents appears to me untenable and the Dresden work reduces me to one of two alternatives. Either the rat tumors are due to the bacterial culture PM or else to some invisible virus attached to the culture and carried along with it. In either event it suggests parasitism. Just as I left Berlin I saw a third rat tumor (good primary, size of the end of my finger, with liver metastasis) produced from a third human breast carcinoma. This is Beta. It was just being transplanted, and I have not heard whether the transplants have grown. I showed the rat slides to Jensen in Copenhagen. He said he had never seen any tumor like it. One he pronounced a sarcoma, another from the same rat "possibly an endothelioma."

I found general scepticism in Berlin and in other parts of Europe as to the value of Dr. Blumenthal's work, but it is well to remember that the attitude of medicine toward any startling new discovery has been always one of rank scepticism, which in many cases is only another name for mental inertia. I have learned, therefore, to discount all criticisms which are not based on good opposing work. There are also many jealousies and much misinformation. The cancer laboratory at the Charity Hospital is poor and has urgent need of money for assistants and for additional animals and animal houses. Just now it would be a good place to put money, hoping for interesting definite returns. A few thousand dollars would be of great service and many a rich man who will die of cancer would not miss it in the least and might render a real service to humanity, just as he might also by giving money to the American Association for Cancer Research.

It is the more interesting that Dr. Blumenthal should have reached the conclusion that the crowngall organism is the type of a whole group of cancer parasites, since originally he shared and expressed the opinion of all German pathologists that the American crowngall studies were of no importance whatever to cancer research and only changed his opinion after studying and experimenting with the plant tumor for half a dozen years.

Professor Gosset, the great surgeon of the Salpêtrière in Paris, has also established a laboratory for the study of crowngall and has put Dr. Magrou, a Pasteur Institute man, in charge of it. Dr. Borrel, in Strasbourg, is also now studying it and a great variety of other tumors very actively and has a superb collection of cancer slides. There also a large amount of research is going on upon tuberculosis,

syphilis, vaccine virus and all sorts of human and animal diseases. Dr. Borrel has found the cornea of rabbits an excellent place for the propagation of vaccine virus and here by staining methods he had demonstrated the presence of great numbers of cocci, sharply stained (I saw them under the microscope) and closely resembling the bodies he has found in Molluscum contagiosum, but from neither disease can they be cultivated. I was much impressed by what I saw in the Strasbourg Medical School. There I was received very courteously and invited to give two lectures to the fourth-year medical students on plant tumors.

Personally, I never thought the crowngall organism could be the cause of cancer in man, but only that cancer might be due to some parasite endowed with similar chemical activities. My reason for disbelief was that, in those strains of the organism which I tested in the thermostat, growth ceased a little under human blood temperature, but always in the back of my thought was the idea that there might be strains of the organism able to grow at 38° C. and for this reason I generally handled the tumors carefully and often sterilized my hands afterward. It was on my mind also to try to educate our strains of the organism to grow at higher temperatures than 36.5° C., but I never found time to try it. I will now try to discover strains able to grow at 38° C.

Looking over the whole field of cancer research I can not resist the feeling that great progress is being made and that the time is not far distant, and perhaps within our own generation, when we shall not only know the cause of human sarcoma and carcinoma, but shall have much better methods of treatment and especially of prevention than any now available. A vaccine is what I hope for and a carrier that may be destroyed, possibly also, a bacterial antagonist. As Pasteur said very often, "The essential thing is to repeat our experiments and not to be discouraged." ERWIN F. SMITH

U. S. DEPARTMENT OF AGRICULTURE,
WASHINGTON, D. C.

DINOSAUR FEED

THE idea that dicotyls arose suddenly about the time smaller mammals appeared and the plant-eating dinosaurs reached maximum size and widest distribution, has led to some quite unimaginative speculation as to ancient reptilian food habits. With Jurassic hillsides so dominantly clothed in araucarians, pines, ginkgos, cycads and ferns, and lowlands beset by scouring rushes and stoneworts, the food of the great browsing animals seemed limited. Zoopaleontologists suggested, for instance, that terrestrial ortho

poda, such as Iguanodon and Camptosaurus, ate the cycads and ferns which grew in such profusion during their day as to provide an "ample nourishment"!

Trachodon of the duck-like bill and fine dental battery, was as well equipped for chewing as the Tertiary and later Pachyderms, and was thought perchance to have lived on plenteously associated equisetes, including of course the rhizomes. "The abundant silica of the cuticle would have necessitated just such a formidable apparatus as the Trachodonts possessed for its proper mastication."

Now, in one of the Trachodont "mummies" various twigs of conifers and dicots, needles of Cunninghamites elegans and numerous seeds or fruits, all in macerated form, have been found by the German paleobotanist Kraeusel. Hence it is likely that some of the dinosaurs of drier habitats pastured on a severer forage than their relatives of the ox-bows, lakes, meadows and edges of moist warm woodlands with a more varied vegetation.

But the actual ecologic conditions of Jurassic and later time and the greater plant alignments presented a different grazing scene. Soil and climate were as varied as now. From the viewpoint of food as made up of root, stem, leaf and fruit, soils sustained as varied growth of nutrient substances as now. Thus, large edible seeds are abundant from the Carboniferous down, while the specialized vegetation, usually first preserved in the fossil form, rarely indicates the exact food source of contemporary life. In considering the meaning even of Jurassic pines as food it is observed that the pine group was then varied, lush of foliage, numerous in species, perhaps five times as numerous as now, and must have included types quite free from the harsher turpentines characteristic of the specialized limited remnant now seen.

Liliaceous plants abounded in the streams and about the lakes of the Trachodon landscapes, and perhaps added to the reptilian dietary. Tangled masses of water hyacinths, like those that at night in the late winter when in bloom simulate ice floes along the upper St. John's River, may feature the plants on which Como dinosaurs fed. No great animals live on pine twigs, on cycads, on ferns, or on scouring rushes to-day, and it is safe to assert that rarely have any fed to any extent on such arrested, aplastic plants in the past. On the contrary, throughout all Triassic and Jurassic time, the land and water plants closely antecedent to the dicots and monocots of to-day, afforded the varied and abundant food on which the dinosaurs lived and often reached gigantism. Climate was only somewhat warmer, in the geographic temperate zones, with stem structure simpler, and foliage less net-veined. As the dinosauria lived throughout the period of development,

of modern stem types and persisted into that of the later dicotyl forests, their disappearance is but indirectly traceable to local loss of food supply due to geologic change. The contemporary plant life as a whole, though not as numerous in species as now, may long have afforded a rather more succulent or more digestible forage than that on which the Indian and African elephant and the rhinocerus thrive.

In all considerations of the food habit of the dinosauria the three factors, climate, habitat, and the prevailing cast of vegetation for the successive periods, must outweigh surmise as to what were precisely the plants on which the particular genus or species lived. Were the hippopotamus only known as a fossil, the habit of feeding on seaweed would scarcely be suspected as one of his aquatic acquirements. While on the other hand the occasional cropping of conifer twigs by the musk ox, and winter season feeding of reindeer on algae are habits of the arctics which have no bearing here, unless showing how far necessity may drive animal life.

Citation of the cycads, particularly those of former desert regions, as a source of dinosaur diet, suggests a further risk of error. Chamberlain, who has seen most of the existing cycads in their habitats, says of the great Macrozamia Moorei of East Australia (23° S. L.), so like Cycadeoidea in both vegetative habit and the free subapical growth of cones:

Unfortunately the leaves of cycads contain a poison which has a disastrous effect upon cattle, and in such a place anything green is likely to prove attractive. The cattle eat the leaves, especially the young leaves, and soon show a kind of paralysis which the cattlemen call "'rickets."' The hind legs begin to drag, giving the animal a peculiar gait, and when it can no longer move about it dies of starvation rather than from the direct effect of the poison. The government is trying to exterminate the plant by poisoning it with arsenic. A notch is cut in the side of the stem, and the arsenic is inserted. The plant soon dies, its leaves droop, and the stem becomes so brittle that the first strong wind completes its ruin. . . . Steps were being taken to create a reservation and thus prevent a plant of such scientific importance from becoming extinct. It seemed nothing short of vandalism to destroy such splendid plants.

If then the dinosaurs toward the close of their long dominance, turned to a cycadeous forage, the cycads could have been one of the causes of their undoing. The gradual development of poisonous principles in the foliage would then have been one of those fortuitous counter-adjustments sometimes seen in nature, tending to survival of the cycadean stock.

Undoubtedly poisonous plants have endangered grazing animals as long as there have been such. Poisonous or deleterious plants must have abounded

always and in all climates, in desert, arid, and wooded regions or plain alike. An enumeration of the more or less poisonous plants of Michigan by Woodcock (Amer. Jour. Botany, Feb., 1925) extends to 156 species above the algae and fungi. Most are angiospermous; but as the case may be, either horses, cattle, sheep, goats or people need to avoid three species of ferns, the field horsetail, two junipers, and the American yew. Leaves of all species of oak are poisonous, when forming the sole food of animals. Many of the various species listed yield prussic acid, and the flowers of the "lily of the valley" and the "meadow saffron" toxic honey.

The dinosaur range was more than once narrowed by geologic events; but Africa and South America, half the land area of the globe, always remained tropic. Dinosaurian life having shown no visible sign of failure to adjust itself to relatively modern environments, loss of either food or habitat does not satisfactorily explain the extinction of the entire race; although it is thinkable that time being long, with waning appearance of new species the ordinary course of geologic change would tend to localize and thin out the older numbers.

Nor is it certain that the dinosaurs were as dependent on warmth as is usually assumed. As Lucas suggested, the lungs may have been more bird-like, the blood warmer than in existent reptiles. Moreover the growth rings of the conifers of the Como in any case indicate sharp seasonal change, and there is no known feature of the vegetation in the Freeze Out Hills or of that further north in the Como dinosaurian range, precluding heavy frosts. Whence one must imagine the Como sauropods retreating into the waters of the protected bayous in the colder season, and stretching their long necks to crop the masses of shore vegetation in the springtime; while as the hot dry summer advanced these animals would venture landward into different herbage for egglaying and any care of the young. Other types of medium size like the orthopoda would perhaps hibernate like tortoises about the edges of the low wooded lands.

The really important phase of dinosaurian dietetics must therefore be the comparative odontography measured in terms of present day life and food,at least with rare exceptions. Plant fossils record only a small percentage of the floras of dinosaur times; while the dinosauria were so varied of structure that they could live in all the terranes of their day from the rivers and lakes to the borders of the plains, and through the shady forests to the edge of the dry desert. Until a greater floral record is revealed in the course of the years, the menu of the dinosaur must remain somewhat in the same category as that of Thomas Hood's Mylodon, which was gen

erous, abundant, and only lacked preparation by a modern chef! Neither harsh "abrasive" foods, nor thyroid-reactive iodine need be looked upon as elements of dinosaurian diet to any extent. Dinosaurs trampling the earth till the grasses grew is only fair evolutionary phantasy. The grasses may be as old as any larger reptiles.

Not to close this suggestion too hastily it is connoted that the lacertilia afford near views of dinosaur-like food habits. Their habits are most varied,

and aside from the many insectivores, larger forms like the Algerian Agamids eat, besides dates, berries, grass and various flowers.

Then amongst the Varanids, the monitors are exceedingly rapacious, at times becoming scavengers. They prey on all animals they can master, and are very active; from which it appears that certain fossil Varanids vieing in size with present day crocodilians, were formidable reptiles which may easily have accounted for some of the past extinction of water fowl and mammals.

More aquatic than any of the monitors, the Galapagos Island Iguanoid, Amblyrhynchus cristatus, is semi-marine, feeding on sea weeds below tide. This animal is an expert swimmer. The teeth are trilobate; the head is covered by low conical scales. And herein lies a further suggestion. The famous Maidstone Iguanodon of the lower Greensand might just as readily have led an aquatic life, feeding on sea weeds, as the turtles or an Iguanoid. A few of the armored dinosaurs also suggest algal pasturage. Such are Hierosaurus of the Niobrara chalk and certain allied European types. The marine occurrence of the dinosaurs has never been closely considered. Though of course, such occasional occurrences as that of the Hadrosaurs in the New Jersey Greensand, in the Niobrara chalk, and again in the upper Pierre, may be without bearing on food habits.

YALE UNIVERSITY

G. R. WIELAND

SCIENTIFIC EVENTS

ROBERT SIMPSON WOODWARD THE following resolution was adopted at the annual meeting of the American Geophysical Union, May 1, 1925:

WHEREAS, We, the members of the American Geophys ical Union, have learned with deep regret of the death of our associate, Robert Simpson Woodward, who, after a lingering illness of 18 months, peacefully passed away on June 29, 1924, in the seventy-fifth year of his age, therefore, be it

Resolved, That we express our deep sorrow in this loss of one who took a prominent part in the formulation of the initial plans which led to the ultimate establishment