all zoological generic names should be regarded as masculine. I enclose herewith a copy of his article on the subject: perhaps you could quote some portions of it in SCIENCE in order to remind the zoological world of an eminently reasonable proposal.

WM. EVANS HOYLE

NATIONAL MUSEUM OF WALES

My suggestion is that a technical specific name in Zoology should be released from the obligation of agreeing with the supposed gender of the generic name to which it is attached.

Simplicity would be attained by acceptance of the convention that in zoology a generic name, whatever its termination, is to be regarded as of the masculine gender.

That some scholarly ear might occasionally be offended, is a minor disadvantage compared with the general utility of the convention. A famous historical character was hailed as "our king Maria Theresa," without any influence on the actual sex of that distinguished person. Similarly many men have been named Maria without in consequence becoming women or in any degree effeminate. The termination of a generic name is a very indifferent reason for determining a zoological species as either masculine, feminine, or neuter, seeing that the species itself usually includes two of the genders, and sometimes all three. Very commonly all the normal individuals of a species are either of the male or female sex. Yet, under the existing rule, the species must sometimes have a neuter name, as though it referred to something inorganic or of undiscriminated sex. Such considerations, however, are of subordinate importance compared with the troublesome character of the present arrangement. As every one is aware, it repeatedly happens that by accessions to knowledge, genera become unwieldy and have to be subdivided. The new names, it may be, do not agree in gender with the old, and then the transferred species must all have their terminations altered. But, apart from this consequential trouble, naturalists for ages past have found the determination of generic genders a stumbling-block. How much more is this likely to be the case in the future, with the continuous decline of classical studies! Without actual examples, few would credit the difficulties encountered and the errors committed by naturalists in their endeavors to comply with the existing rule or practise.-T. R. R. Stebbing in Knowledge (1910).

HAY FEVER AND THE NATIONAL FLOWER TO THE EDITOR OF SCIENCE: The attention of the American Hayfever Prevention Association has been called to the article on "Hay Fever and the National Flower" in a recent issue of your journal.

The research department of this association, which was established in 1915, has made a thorough investigation of the causes of hay fever, being assisted in this work by specialists and botanists in practically every state of the union. The pollens of all the most common plants and trees have been tested and their relation to hay fever established.

Generally speaking, the principal causes of fall hay fever in the northern, eastern and southern states1 are the pollens of the ragweeds (Ambrosiaceae), these being replaced in the Pacific and Rocky Mountain States2 by the wormwoods (artemisias) The chief causes of spring hay fever are the pollens of the grasses in all sections. About five per cent. of hay fever cases are due to other pollens. The golden rod, however, is not included in these, having proven a clear " alibi.”

For those not already familiar with the subject, the following statement is made:

THE GOLDEN ROD IS NOT RESPONSIBLE FOR HAY FEVER

1. It does not conform to the description of hay fever plants, which is as follows:3 (1) They are wind-pollinated, (2) very numerous, (3) the flowers are inconspicuous, without bright color or scent, and the pollen is formed in great quantities. The flowers of the golden rod are insect-pollinated, have bright colors and scent, and the pollen is not formed in large quantities.

1"Hayfever: Its Cause and Prevention," W. Scheppegrell, M.D., Journal of the American Medical Association, March 4, 1916.

2"Hayfever: Its Cause and Prevention in the Rocky Mountain and Pacific States," W. Scheppegrell, M.D., United States Public Health Reports, July 20, 1917.

3"Hayfever and Its Prevention," W. Scheppegrell, M.D., United States Public Health Reports, July 21, 1916.

2. The golden rod continues to bloom for several weeks after the hay fever season is over. In western North Carolina, for instance, the hay fever season concludes about October 1, but the Canadian golden rod (Solidago canadensis) brightens the autumn landscape until November. In our hay fever clinic at the Charity Hospital of New Orleans, the fall hay fever season concludes about October 26, but the golden rod continues to bloom until December.

3. Our research department exposes its atmospheric-pollen-plates in various parts of the United States, and in this way, the atmospheric-pollens are caught and examined. The pollens of the golden rod are never found on these plates, proving that this pollen is not atmospheric. Unless the pollen is in the air, as in the cases of the ragweeds, grasses and other wind-pollinated plants, it can not cause hay fever unless the nostrils are applied directly to the flower, or are used in large quantities for room decorations, in which case the pollen may fall within the limited space.

The pollen of the golden rod may cause a reaction when applied directly to the nostrils, or when used in large quantities for room decorations. As far as being a cause of hay fever, however, it is absolutely negligible. It is one of our most beautiful flowers, and well merits its selection as the national flower of the United States.

W. SCHEPPEGRELI AMERICAN HAYFEVER PREVENTION ASSOCIATION; CHIEF OF HAYFEVER CLINIC, CHARITY HOSPITAL; EX-PRESIDENT AMERICAN ACADEMY OF OPHTHALMOLOGY AND OTOLARYNGOLOGY

SCIENTIFIC BOOKS Manual of Meteorology, Part IV. The Rela tion of the Wind to the Barometric Pressure. By SIR NAPIER SHAW, Cambridge, University Press. 1919.

4"Susceptibility to Hayfever, and Its Relation to Heredity, Age, and Seasons," W. Scheppegrell, M.D., United States Public Health Reports, July 19, 1918.

The British Meteorological Office during the past four years has been called upon to answer a good many questions put to them by the Army, Navy and Air Services. The requests for detailed information regarding wind, weather and the structure of the atmosphere were numerous and urgent. For in both. offensive and defensive operations the military authorities suddenly realized how all important a knowledge of aerography was. In attempting to give definite data, Sir Napier Shaw, as Scientific Advisor to H. M. Government and chairman of the Meteorological Committee, says that he found as a guiding principle of great practical utility, the relation of the wind to the distribution of pressure. The underlying assumption is that the flow of air in the free atmosphere follows very closely the laws of motion under balanced forces, depending upon the spin of the earth and the spin in a small circle on the earth.

There are eleven chapters in the book. The opening chapters give details of the determination of the pressure gradient and the wind. Land and sea relations of surface wind to the gradient, turbulence in relation to gustiness and cloud sheets, eddy clouds, the dominance of the stratosphere, coastal refraction of isobars and the dynamical properties of revolving fluid in the atmosphere, are treated in some detail in successive chapters.

Space permits of but one quotation from the book and that is almost the last paragraph; but here the author drives another nail in the coffin of the convectional theory of the cause of cyclones.

It has long been supposed that the variations of temperature at the surface are themselves the cause of the original circulation of the cyclone, but it is much more easy to explain convection along the core as the effect of an existing circulation above, than vice versa, and there are so many examples of convection attended even by copious rainfall which produce no visible circulation that it is difficult to regard convection from the surface as a sufficient cause of our numerous depressions.

Sir Napier deals at some length with the relation between the surface wind and the geostrophic wind at sea-level. This is pecul

iarly his own field, and is in fact a development of the past six years. It is a distinctive contribution of the British school of aerographers. We may explain that the balance between pressure and velocity of air flow, or what is known as the strophic balance, leads to an equation for the gradient wind of the following form:

8=2wvp sin ± v2p cot r/E

The first term in the right-hand member of the equation represents velocity due entirely to the earth's rotation and hence is known as the geostrophic wind. The other is known as cyclostrophic. Only a few months ago J. S. Dines called attention to a rather remarkable outcome of this equation, where in the case of a path concave to the "low," velocities of the order of 6m/s for normal counter-clockwise rotation, and 46m/s for rotation in the opposite direction, appear to be possible. Thus a depression revolving with high speed in a clockwise direction in the northern hemisphere is dynamically possible. There are reasons why such an eddy on a large scale might not be established or last long, but small area eddies such as those around high buildings, etc., evidently can be set up with rotation either clockwise or anti-clockwise. This raises the question, How often are dust-whirls, tornadoes, and waterspouts observed with a clockwise rotation?

Sir Napier Shaw uses as a frontispiece a chart showing paths of the centers of some notable cyclonic depressions of long duration. One is the path of a baguio traced by McAdie from lat. 15° N. in the western Pacific, starting on November 20, 1895, and reaching the Oregon-California coast January 12, 1896, a rather definite duration of 54 days at sea and a probable history of 4 days more in the United States and 5 days over the North Atlantic. Two other long duration storm paths are given.

These paths of long duration are significant in connection with origin, directive force and persistence of structure of cyclones and anticyclones. The most pressing question to-day before aerographers is accurate knowledge of

the driving forces of a depression, and the directive resultant. There can be no accurate forecasting without this knowledge.

We are promised three more volumes from the University Press; one, a general survey of the globe and its atmosphere. A second on the physical properties of the atmosphere, and a third, a formal exposition of the dynamics and thermics of the atmosphere.

Sir Napier Shaw is to be congratulated not only on the output from his own industrious pen, but upon what he has accomplished in stimulating the young men around him, Lempfert, Dines, Gold, Cave, Taylor and others.

A. M.

THE NATIONAL ACADEMY OF

SCIENCES

THE eleventh number of Volume 4 of the

Proceedings of the National Academy of Sciences contains the following articles:

The "Homing Habits" of the Pulmonate Mollusk Onchidium: Leslie B. Arey and W. J. Crozier, Bermuda Biological Station for Research, Dyer Island, Bermuda. Onchidium floridanum lives during high tide in nests," i. e., rock cavities, containing a number of individuals. The individuals leave the nest in low water to feed, and return simultaneously to it before the tide rises again, giving evidence of homing behavior.

Growth and Duration of Life of Chiton Tuberculatus: W. J. Crozier, Bermuda Biological Station for Research, Dyer Island, Bermuda. The growth curve is obtained on the assumption that the age of a chiton may be estimated from the growth-lines upon its shell. The mean duration of life is probably a little less than eight years.

Growth of Chiton Tuberculatus in Different Environments: W. J. Crozier, Bermuda Biological Station for Research, Dyer Island, Bermuda. Growth curves obtained under different conditions are compared.

The Interferometry of Vibrating Systems: C. Barus, Department of Physics, Brown University. The high luminosity of the achromatic interferences and the occurrence of but

two sharp fringes make it possible to utilize them even in cases when the auxiliary mirrors vibrate. The vibration interferometer is quite sensitive, provided the average currents are of the order of several microamperes.

On the Essence of Physical Relativity: Sir Joseph Larmor, Cambridge, England. A general discussion of the physics underlying relativity, with particular reference to an article by Leigh Page.

Gravitational Attraction in Connection with the Rectangular Interferometer: Carl Barus, Department of Physics, Brown University. The rectangular interferometer is so sensitive in the measurement of small angles that it may be used for the measurement of the Newtonian constant of gravitational attraction.

The General Character of Specific Heats at High Temperatures: Walter P. White, Geophysical Laboratory, Carnegie Institution of Washington. The general law covering the behavior of atomic heats from the lowest temperatures up demands that at sufficiently high temperatures all atomic heats at constant volumes should have the value 5.96. A contrary hypothesis has been made, namely, that atomic heats continue to increase with the temperature. The substances here examined give evidence that the atomic heats do increase above the value 5.96.

On Certain Projective Generalizations of Metric Theorems, and the Curves of Darboux and Segre: Gabriel M. Green, Department of Mathematics, Harvard University. The continuation of earlier work by the same author in the Proceedings.

The Rectangular Interferometer with Achromatic Displacement Fringes in Connection with the Horizontal Pendulum: Carl Barus, Department of Physics, Brown University.

THE twelfth number of Volume 4 contains the following articles:

The Absorption Spectrum of the Novae: W. S. Adams, Mount Wilson Observatory, Carnegie Institution of Washington. A discussion of Nova Aurige of 1892, Nova Persei of 1901, Nova Geminorum of 1912, and Nova Aquila of 1918. The displacements of the lines in all

these stars are directly proportional to wavelengths, and divide themselves into two pairs of equal amount. Of these the first pair of stars has exactly twice the displacement of the second. In the case of Nova Aquila, there is a progressive increase in the values of the displacements of the absorption lines at successive dates. Various hypothetical explanations are discussed.

On Jacobi's Extension of the Continental Fraction Algorithm: D. N. Lehmer, Department of Mathematics, University of California. A closer study of Jacobi's expansion reveals a number of remarkable points. Six theorems are stated.

A Characterization of Jordan Regions by Properties having no reference to their Boundaries: Robert L. Moore, Department of Mathematics, University of Pennsylvania. The theorem is proved: In order that a simply connected, limited, two-dimensional domain R should have a simple closed curve as its boundary it is necessary and sufficient that R should be uniformly connected im kleinen.

A Biometric Study of Human Basal Metabolism: J. Arthur Harris and Francis G. Benedict, Nutrition Laboratory and Station for Experimental Evolution, Carnegie Institution of Washington. An analysis of measurements on 136 men, 103 women, and 94 new-born infants.

Sex and Sex Intergrades in Cladocera: Arthur M. Banta, Station for Experimental Evolution, Carnegie Institution of Washington. The presentation of facts in regard to Cladocera, with the discussion of their significance with regard to sex intergrades in general, leading to the tentative conclusion that sex is always relative and that while most individuals of whatever species are prevailingly male or prevailingly female, every individual may have something of the other sex intermingled with its prevailing sexual char

acters.

On the Method of Progression in Polyclads: W. J. Crozier, Bermuda Biological Station for Research, Dyer Island, Bermuda. In turbellarians generally, muscular operations analogous to those executed by the foot of chitons

and of gastropods are essentially concerned in creeping locomotion.

The Phylogeny of the Acorn Barnacles: Rudolf Ruedemann, State Museum, Albany, N. Y. The derivation of an Eobalanus from a Rhinocaris-like phyllopod is illustrated in a set of diagrams.

Possible Derivation of the Lepadid Barnacles from the Phyllopods: John M. Clarke, State Museum, Albany, N. Y. So far as present knowledge extends, the metamorphoses of the phyllopods into the two great branches of the barnacles were essentially contemporaneous.

Refractive Index and Solubilities of the Nitrates of Lead Isotopes: Theodore W. Richards and Walter C. Schumb, Wolcott Gibbs Memorial Laboratory, Harvard University. The difference in atomic weight of the lead (207.20 and 206.41) has no appreciable effect on the refractive index or on the molal solubility of the different samples of lead nitrate.

The Purification by Sublimation and the Analysis of Gallium Chloride: Theodore W. Richards, W. M. Craig and J. Sameshima. Wolcott Gibbs Memorial Laboratory, Harvard University. The method rests on the fact that gallium trichloride sublimes and distils at a low temperature, whereas the other chlorides likely to be associated with it are much less volatile.

The Purification of Gallium by Electrolysis, and the Compressibility and Density of Gallium: Theodore W. Richards and Sylvester Boyer, Wolcott Gibbs Memorial Laboratory, Harvard University. The method of separating gallium from indium by means of the different solubilities of the hydroxides in caustic alkali was tested without success; much more promising results were obtained by the electrolytic method. The compressibility of solid gallium was found to be 2.09 X 10-6, and of liquid gallium 3.97 X 10-, nearly twice as great, although its volume is less. The density of the liquid was 6.081, and of the solid 5.885. The Growth-rate of Samoan Coral Reefs: Alfred G. Mayor, Department of Marine Biology, Carnegie Institution of Washington. the growth rate of Acropora, Porites, Pocillopra, Pavona, Psammocora are given; and the

weight of limestone added per year to the upper surface of the Aua reef-flat is estimated as 805,000 lbs. Other similar estimates are given.

The Distances of Six Planetary Nebula: Adriaan van Maanen, Mt. Wilson Solar Observatory, Carnegie Institution of Washington. The nebula N.G.C. 2392, 6720, 6804, 6905, 7008 and 7662 are examined. The parallaxes range from 0."002 to 0."021, and the diameters from 10,000 to 1,350 astronomical units.

National Research Council: Minutes of the Meeting of the Executive Board, July 9, August 13, September 9 and October 8.

We may summarize the articles in Volume 4 of the Proceedings as follows: Mathematics, 9; Astronomy, 11; Physics and Engineering, 25; Chemistry, 5; Geology and Paleontology, including Mineralogy and Petrology, 9; Botany, 3 (see also Genetics); Zoology, including General Biology, 12 (see also Genetics); Genetics, 6; Physiology and Pathology, 10; Anthropology and Psychology, 1; a total of 91 articles.

The division of these articles between members of the Academy and non-members is 39 and 52 respectively.

The list of institutions which have contributed three or more articles is as follows: Carnegie Institution, 15, divided as follows: Solar Observatory, 7, Nutrition Laboratory, 4, Geophysical Laboratory, 1, Marine Biology, 1, Station for Experimental Evolution, 1, Tortugas Laboratory, 1; Harvard University, 15; Brown University, 7; University of Illinois, 5; Bermuda Biological Station for Research, 4; University of California, 4; University of Chicago, 4; University of Pennsylvania, 4.

EDWIN BIDWELL WILSON MASSACHUSETTS INSTITUTE OF TECHNOLOGY, CAMBRIDGE, MASS.

SPECIAL ARTICLES

OPPORTUNITIES FOR CONTACT INFECTION1

AN outstanding feature of the influenza pandemic is the remarkable infectivity of the disease. There is scarcely a community in 1 Published by permission of the Surgeon-General of the Army.