Lapas attēli

4 mm, to 5 mm. it can be seen that the sexual specimens and be difficult if not impossible dimorphism can be noted at a very early stage. to detect in measurements of preserved Even in the smaller stages the males have a material. distinctly larger oral sucker than the females Recently in some studies on a species of and the body is wider. Also early in develop- schistosome cercaria with eyespots from Planment the females show a larger space between orbis trivolvis from Douglas Lake, Michigan, the intestinal ceca in front of their point of I have been able to demonstrate two distinct union than do the males. As development size types. This difference in size came to my proceeds the differences in size between the attention first when I found that the curve suckers of the sexes becomes more distinct. plotted from the measurements of cercariæ The males become broad and flat and finally from a number of infected snails was disthe sides of the post-acetabular region curl tinctly bimodal. More extensive studies up to form the gynæcophoric canal. In the showed that the cercariæ of this species fell females the body tends to become round in into two distinct size groups. I further cross section and the width is constantly found from measurements of the cercariæ much less than that of males of the same age. from eleven infested snails that in the cercariæ A detailed description of this development coming from a single snail only one of the will be made in a future publication. Fuji- size types was represented. The difference in nami and Nakamura in a paper published size was so great between these two types that in Japanese antedate my findings on early sex it could be recognized with the naked eye dimorphism in Schistosoma japonicum. They when free-swimming cercariæ of the two types were able to distinguish the sexes in speci- were placed in separate bottles. Measuremens 0.5 mm. to 0.7 mm. in length, which ments of the length of the body of the larger developed in dogs. They laid especial em- type showed a range of variation from 0.234 phasis on differences in the width of the body mm. to 0.28 mm. while in the smaller type and in the character of the intestinal ceca the range was from 0.207 mm. to 0.24 mm. as characters for distinguishing sex.

Other measurements of the body and tail, The next question which arises in this con- which in this species is unusually large, nection is whether sexual dimorphism is showed like differences. The adult into which present in schistosome cercariæ. Although this cercaria develops is not known, although many workers have made studies and meas- unsuccessful attempts were made to introduce urements of the cercariæ of the human

it into ducks and rats. An analysis of its schistosomes no one has reported such differ- structure, however, places it near to the ences. I have myself examined a number of

human schistosomes in the family Schistocercariæ of S. japonicum with this point espe

somidæ. This relationship means that in all cially in mind without noting any dimorph- probability in the adult stage of this species ism. Dr. S. Yokogawa, of the Medical College

the sexes are separate. I therefore interpret of Formosa, also informs me that he has the size differences in this species of cercaria made an extensive series of examinations and as a sexual dimorphism. If this view is acmeasurements of this cercaria in an attempt cepted the fact that in one infested snail only to find sexual differences without success.

one of the types of cercaria is represented Since the cercariæ of the human schistosomes immediately becomes very significant. A more are very small and can extend and contract

detailed account of the dimorphism of this their bodies to an unusual extent, slight size species of cercaria will be published later in differences might escape notice in the living

connection with a study of its structure and

activities. 2 Fujinami, A., and Nakamura, H., 1911, A

In this connection must be cited the work demonstration of some specimens showing the development of Schistosoma japonicum(Japanese).

of Tanabe, Schistosoma japonicum. Bio ri Gaku Kaishi, Vol. 1.

3 Tanabe, K., 1919, A contribution to the


This author found that in twenty-six out of

ORIGIN OF POTATO RUST1 thirty-one cases when the cercariæ from a

A YEAR ago the writer called attention to single snail were used in infesting experi

the threatened introduction into the United mental animals all the individuals developed

States of two more crop pests, the potato rust, were of the same sex. Dr. S. Yokogawa has

Puccinia Pittieriana, and the peanut rust, given me permission to use in this connection

Puccinia Arachidis.2 Since then the latter the results of some of his experiments along fungus has been found in one field in Florida, this line, which were performed several years

where all vestige of it was at once destroyed. ago. He found that when a cat, dog, or rab

The other fungus has not yet appeared in the bit was infested with the cercariæ from a single United States. snail that worms of only one sex would de

During 1918 the potato rust was very velop. He also found that in these cases the

abundant and harmful in the experiment worms would not develop to maturity. These

station grounds at Ambato, Ecuador, not only two workers have developed independently

upon potatoes but even more so on tomatoes. the same hypothesis to explain the results of

This was the first report of the rust in South these experiments.

America, having previously been known only According to this hypothesis sex in the

from the high lands of Costa Rica on the schistosomes is determined in the fertilized potato alone. In Ecuador it showed decided egg and all the cercariæ coming from a single preference for North American varieties of miracidium are of the same sex. When all the tomato. An excellent illustrated account the individuals derived from the cercariæ from of the rust and its behavior, with conjectures a single snail were of the same sex it would

on its origin, was published in the bulletin of follow that the infestation in this snail was the Ambato station for January, 1920, by the from a single miracidium or two or more station botanist, Abelardo Pachano.3 I take miracidia of the same sex.

In those cases the liberty to quote a few disconnected senwhere both sexes came from the same snail, tences from this article, after changing them this snail must have been originally infested from the Spanish into an English garb. with two or more miracidia representing both

The rust of the tomato and potato is a wholly sexes. Now my findings recorded above in re

new disease, not only in our fields (in Ecuador), gard to dimorphism in a species of schisto

but also elsewhere. Not simply the fact of its nov. some cercaria, and the presence in one snail of

elty should interest us, but more particularly its only one of these types, lends further support virulence, its ease of propagation, and the enorto this hypothesis. Further, since in the life

mous injuries that it occasions; these consideracycle of 8. japonicum, the miracidium and the tions would seem to place it among the most seri. mother sporocyst are the only stages derived ous maladies of cultivated crops. from a fertilized egg, it is in these stages that The history of this rust [in this region] may be sex differentiation would theoretically be ex- easily sketched. The year 1918 is demonstrated as pected. Up to the present time, however, no

the date of its first appearance. In fact in the

spring of that year we had occasion to observe one has examined these stages to determine whether they show a sexual dimorphism. My

very grave disturbances, by our horticulturists

given the general name of plague, in the tomato purpose in discussing the data given above

plots from seed of North American origin. The and the hypothesis derived from them in this

varieties most attacked were those by the names preliminary way is to call the attention of

Acme, Golden Queen and Black-eyed State. zoologists interested in the problems of sex to Nearly at the same time we noted similar lesions the interesting condition found in this trema

1 Presented to the Mycological Section of the tode family.


Botanical Society of America at the Chicago meetknowledge of the morphology and development of ing, December 29, 1920. Schistosoma japonicum" (Japanese). An abstract 2 SCIENCE, 51: 246–247, March 5, 1920. of a paper given before the Japanese Pathological 3 Boletin de Agricultura Quinta Normal, 1: 7-12, Society. Igaku Chuo-Zashi, Vol. 17, No. 6. Figs. 1, 2, January, 1920.

in the parcels of potatoes of the variety Calvache. smaller spores than the potato rust. Only But although the malady has increased very rap- actual trial can show if these forms can be idly and is abundant in the tomato plots, it has

transferred from one host to another, and if not flourished in those of the potato.

the size of the spores is in anywise dependent Where did this new parasite come from? We

upon the host. have not met with it up to the present on any of

A variation in spore-size apparently deour wild Solanacea, so as to enable us to infer that it has been transferred from them to the

pendent on the host is found to occur in the potato and tomato; neither has seed been received

case of the snapdragon rust, and cases of such from Costa Rica so we could believe that it has

size variation are known for other species, come from that locality. The trouble, as it has some of them authenticated by pedigree culmanifested itself, has appeared on plots grown tures. The spores from the potato and tomato from North American seed, in a way to make us are remarkably uniform in size. Whether the think that this new plague is to be referred to the three forms of Solanaceous rusts here referred United States,

to are the same or not, it is fairly safe to Mr. Pachano informs me by letter that the

predict that the potato rust has originated disease was not so prominent during 1919 as

somewhere between Ecuador and Costa Rica it was in 1918, but had the same relative pre- on hosts native to the localities. dominance on the tomato, especially on the

J. C. ARTHUR North American varieties. He has also modi.

PURDUE UNIVERSITY, fied his views regarding its origin. We may

LAFAYETTE, INDIANA assume, I think, that the susceptibility of North American varieties has no special significance in connection with the question of

SCIENTIFIC EVENTS the native host or habitat. The snapdragon

A WORLD ATLAS OF COMMERCIAL GEOLOGY rust has been known since 1897, and has With the growth of American industries spread throughout the United States, but only the known and the possible sources of our recently has it been traced to its native Cali

supplies of raw materials have become of fornian hosts. In fact I think we can safely greater and more pressing interest. Even the assume that the appearance of the potato rust United States—most favored of nations in in the gardens of central Ecuador indicates

abundance and variety of raw materials—can that the rust can be found on uncultivated

not be self-sufficient; it must look beyond its native plants in that same region. The

shores for supplies as well as for markets. Solanum rusts of tropical and semi-tropical

The study of the distribution of mineral raw America are numerous, but have been little

materials and their relations to the promotion studied, and those of Ecuador almost not

of trade and the control of industry is a at all. There is a rust described from Colombia

branch of geology and may best be termed

commercial geology. Under the complex reon Sarache edulis, a close relative of Solanum, which much resembles the potato rust except

quirements of present-day life no continent, that it has slightly larger spores. This same

not even North America, can be self-sustainrust on another species of Sarache was found ing. It is no longer enough for us to make in the vicinity of potato rust on Mt. Irazú in

an inventory of the mineral wealth of the Costa Rica by E. W. D. Holway, who tells

United States; we must supplement that inme that the plant is common in gardens there, ventory by a broad understanding of world going by the name “ yerba mora.” There is demand and supply. To set forth graphically also a very similar rust known on the wild and to describe concisely the basic facts conSolanum triquetrum, a vine ranging south- cerning both the present and the future ward from central Texas into the adjacent sources of the useful minerals is the purpose region of Mexico, but this form has slightly of a World Atlas of Commercial Geology just

issued by the United States Geological Survey, Department of the Interior.

The output of the essential minerals in 1913, the latest normal year, may at least be regarded as a measure of the “ quick assets" possessed by each nation, and the first part of the World Atlas of Commercial Geology has therefore been planned to show the distribution of mineral production in 1913.

The practical value of this exhibit of the world's mineral assets is evident. Experience gained during the World War emphasizes the advantage of an adequate supply of raw materials close at hand, yet that there are certain economic limits to domestic independence in raw materials is clearly shown by the readjustments already made. The more facts we possess bearing upon the relative quantity and the relative availability of the mineral resources of our own and of other countries, the better able will be our captains of industry to decide whence they should derive their raw material. The mines of the United States should be looked upon primarily as tributary to the many mills, shops, and factories in which the skilled labor of the country may find its opportunity for a livelihood. The output of raw minerals measures only the first step in industry.

More than score of geologists have cooperated in the preparation of this atlas, which was first undertaken during the World War as a part of the task of keeping American industries supplied with raw material and is to be regarded therefore as a byproduct of the war-time activities of the Geological Survey.

tablishment of a recording microphotometer of the type suggested in 1912 by P. Koch.

(3) 3,000 francs to Henry Bourget, director of the Marseilles Observatory, for the Journal des Observateurs.

(4) 2,000 francs to Clément Codron, for his researches on the sawing of metals.

(5) 5,000 francs to the School of Anthropology, for the publication of the Revue d'Anthropologie,

(6) 4,000 francs to Justin Jolly, for the publication of a work on blood and hematoporesis.

(7) 7,000 francs to Louis Joubin, for the publication of the results of the French Antarctic Expedition,

(8) 3,000 francs to the late Jules Laurent, for the publication (under the direction of Gaston Bonnier) of a work on the flora and geography of the neighborhood of Rheims.

(9) 3,000 francs to Henri Brocard and Léon Lemoyne, for the publication of the second and third volumes of their work entitled "Courbes géométriques remarquables planes et gauches."

(10) 2,000 francs to A. Menegaux, for the Revue française d'Ornithologie.

(11) 5,000 francs to Charles Nordmann, for his researches on stellar photometry.

(12) 8,000 francs to the Zi-Ka-Wei Observatory, in China (director, R. P. Gauthier), for recording time-signals from distant centers.

(13) 2,000 francs to 0. Parent, for his studies on a group of Diptera.

(14) 10,000 francs to G. Pruvot and G. Racovitza, directors of the Archives de Zoologie expérimentale et générale, for this publication.

(15) 6,000 francs to Alcide Railliet, for the publication of researches on the parasites of the domestic animals of Indo-China.

(16) 4,000 francs to J. J. Rey, for the publication of a botanical geography of the Central Pyrenees.

(17) 10,000 francs to Maximilien Ringelmann, for researches relating to the physical and mechanical constants of metals intended to be used in the construction of agricultural machines.

(18) 12,000 francs to the Academy of Sciences, for the establishment of a catalogue of scientific and technical periodicals in the libraries of Paris.

It was pointed out by the council in 1917, that, although the special object of this foundation was the promotion of original research, up to that time requests for assisting work to be carried out according to a well-defined scheme had been exceedingly few in number.



OF THE PARIS ACADEMY AMONG the awards made this year, as we learn from the report in Nature, are the following:

(1) 10,000 francs to Charles Alluaud and to R. Jeannel, for the study of the zoological and botanical material collected by them in the high mountains of eastern Africa and for the publication of the results.

(2) 5,000 francs to Jules Baillaud, for the es


of California, San Francisco, Calif.; E. H. The American Society of Tropical Medi

Ransom, Department of Agriculture, Washcine announces a new publication for phys- ington, D. C.; R. P. Strong, Harvard Uniicians and research workers, to be known as versity; A. J. Smith, University of PennsylThe American Journal of Tropical Medicine. vania; E. R. Stitt, surgeon general, U. S. The announcement says:

Navy; W. S. Thayer, Johns Hopkins Uni“The general experience of the medical sci- versity; E. J. Wood, Wilmington, N. C.; ences has fully demonstrated the advantages E.c-officio Advisory Editorial Board, The which accrue from the segregation of special American Society of Tropical Medicine: J. M. subjects. A central organ for the prompt Swan, president; K. F. Meyer, first vice-presipresentation of articles, that are now scattered dent; V. G. Heiser, second vice-president; over a wide field, or the lack entirely of a S. K. Simon, secretary and treasurer; A. J. proper medium to turn to for publication, will

Smith, assistant secretary and treasurer; be a great convenience to those interested in

George Dock, councillor; C. L. Furbush, the study of tropical diseases, and also serve to councillor; J. F. Siler, councillor; J. H. stimulate the growth and development of the White, councillor; C. S. Butler, councillor. subject. The purpose of the new JOURNAL will be to serve as a medium for the dissemi

THE SCIENTIFIC STAFF OF THE AMERICAN nation of reliable information from every

MUSEUM OF NATURAL HISTORY source, with regard to the clinical and other IN appointing the scientific staff of the phases of the nature, treatment, and preven- American Museum of Natural History for tion of tropical diseases."

1921, the board of trustees has made a The JOURNAL will be published bi-monthly number of changes and promotions, some of by the Williams and Wilkins Company, Bal- which have already been noted in SCIENCE. timore, Md. The transactions of the annual The senior curator of the staff, Dr. Joel A. meetings of the American Society of Tropical Allen, has been promoted to be honorary Medicine will be published in the JOURNAL. curator of mammals, in order that he may Various reports, lists of members, and such devote his entire time to his researches. Dr. other information as may be suitable will also Allen is in his eighty-third year and for more appear. Other papers, whether from members

than 35 years has been the head of the deor not, will also be published.

partment of mammalogy. This relief from The following are members of the editorial

the responsibility of administrative work staff:

comes as a welcome change to Dr. Allen, who Editor: H. J. Nichols, Medical Corps, U. S.

speaks of his new appointment in the followArmy, Army Medical School, Washington,

ing language: D. C.; Advisory Editorial Board: B. K. Ashford, Medical Corps, U. S. Army, San Juan,

I wish to express to you, and through you to Porto Rico; C. C. Bass, Tulane University,

the board of trustees, my deep appreciation of this New Orleans, La.; M. F. Boyd, University of

honor, and of the privileges accompanying it, thus

awarded me. It will be a great solace to me durTexas, Galveston, Texas; C. F. Craig, Medical

ing such time as may remain to me for the proseCorps, U. S. Army, Army Medical School,

cution of research work, which I am still able to Washington, D. C.; George Dock, Washing

pursue with unabated zest and pleasure. ton University; Simon Flexner, Rockefeller Institute, New York City; William Krauss,

The trustees have created a new departMemphis, Tenn.; W. D. McCaw, Assistant ment designated as comparative anatomy and Surgeon General, U. S. Army, Army Medical have appointed Dr. William K. Gregory to the School, Washington, D. C.; G. W. McCoy, curatorship as a recognition of Dr. Gregory's director, Hygienic Laboratory, U. S. P. H. S., contributions to anatomy and vertebrate

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