AIRGRAPHY OR AEROGRAPHY?

IN the Bulletin of the American Meteorological Society (April 1927, p. 69) the suggestion is made that the word aërography (study of the air) henceforth should be written airgraphy. On this side of the Atlantic we have done away with the word aëroplane (which certain of the Boeotians pronounced a-ery-o-plane) and use the simpler, equally expressive term airplane.

A new reason for adopting the change is found in the increasing use of the word areographic by astronomers in connection with planetary atmospheres.

Thus, Professor W. H. Wright, of the Lick Observatory, discussing the ice cap on Mars speaks of "the exact areographic position of every cloud or atmospheric peculiarity."

If we are to continue the use of aerographic and areographic, we offer the types a fine opportunity to do their worst in transposition; to say nothing of professorial orthography!

And, while we are about it, can we not abandon meteograph and meteotherm for airgraph and airtherm?

BLUE HILL OBSERVATORY

ALEXANDER MCADIE

"ASTRONOMIC "

WHO introduced the word "astronomic" into astronomic literature and why did he do it? "Special Publication No. 110 of the U. S. Coast and Geodetic Survey" is entitled "Astronomic Determinations." Plans have been made for "An Ideal Astronomic Hall" in the American Museum of Natural History, though there is some comfort in the fact that it is "to be devoted to astronomical and kindred subjects We even find the terms "astronomic latitude" and "astronomic time" in a recently published astronomic text-book. I see no object in lining up the comfortable old word "astronomical" with geocentric, pneumatic, egophonic and gastronomic. If we don't look out, some one will take all the joy out of our new word "astrophysical."

RAYMOND S. DUGAN

PRINCETON UNIVERSITY OBSERVATORY

SCIENTIFIC APPARATUS AND

LABORATORY METHODS DIRECTIONS FOR DETERMINING THE COLLOIDAL MATERIAL OF SOILS BY THE HYDROMETER METHOD

IN the issue of October 8, 1926, of this journal there appeared a brief article proposing the hydrom

eter method as a very rapid means of determining the colloidal content of soils. Since the publication of this paper a great number of letters have been received asking for more detailed information as to technique, kind of hydrometer used, etc. In view of this large number of inquiries, it has seemed advisable to publish in advance of the main report the directions for executing a colloidal determination and other essential information concerning the method.

The use of the hydrometer method for determining the colloidal content of soils in only fifteen minutes is based upon the fact that there is a remarkably close relationship between the colloidal content of soils as determined by the heat of wetting method and the percentage of material, based on the sample taken, that stays in suspension in a liter of water, at the end of fifteen minutes. There is a fundamental basis for this relationship, for it holds true for all types of soils and various amounts of samples taken. The only soils that do not give a very close relationship are the peats and mucks and this is because it is almost impossible to disperse those organic materials.

The success of the hydrometer method for determining colloids is based upon a complete dispersion of the soil. This can be accomplished remarkably well and most rapidly by means of a stirring motor, such as is used in mixing malted milk. In using this machine, however, care must be taken to use a special cup made purposely with baffles in it in order to prevent the circular motion to which the soil-water mixture is subjected without these baffles. The machine will disperse a soil in ten minutes which an ordinary shaker will require more than twenty-four hours to accomplish.

The soils can be dispersed also by hand from about ten to fifteen minutes, but such dispersion can not be uniform and not always complete and consequently is not recommended. If it is absolutely necessary to disperse by hand, then the following procedure may be followed. Place fifty grams of soil, 100 grams in case of sandy soils, based upon the dried basis in a mortar, add enough distilled water to make a paste and pestle vigorously. Add more water to make a thin suspension, stir, let it stand half a minute and pour supernatant liquid in the cylinder. Pestle the paste again vigorously and again add water to make suspension and at the end of half a minute pour supernatant liquid in the cylinder. Continue this operation until all the clays are dispersed or the liquid is almost clear. To the mixture add 5 cc of 1N KOH. For making hydrometer readings follow directions given below.

If the stirring motor is used, the procedure is as

t

t

e

follows: Place fifty grams of dry soil in the cup, in the case of sandy soils 100 grams, add 5 cc of 1N KOH, fill cup with distilled water one and one half inches from the top and stir it by the motor for nine minutes. The mixture is then washed into a cylinder having a total capacity of about 1,130 cc. The hydrometer is placed in the cylinder and the latter is filled clear to the top with the hydrometer still in it in order to facilitate the reading of the hydrometer from the top of the liquid column. The hydrometer is then taken out, and the mixture is stirred vigorously for about a minute, using one palm as a stopper. The cylinder is placed on the table and the time is quickly noted, preferably by a stop watch. The hydrometer is put in the mixture and at the end of fifteen minutes the reading is noted. Just about half a minute before the fifteen-minute period is up, however, the hydrometer is pushed down gently in order to avoid any lagging. The reading, which is grams per liter, is divided by the weight of sample taken, and the result is percentage of colloids in that soil. The temperature of the mixture is also noted and the necessary correction made. All readings must be reduced to 67° F., which is the temperature at which the hydrometer was calibrated. A change of 1° F. makes a difference of about 0.35 per cent. of colloids. For temperatures above 67° F. the corresponding amount is added to the percentage indicated by the hydrometer, and for temperatures below 67 the amount is subtracted.

The hydrometer gives an average measurement of the densities for the entire column of liquid, down to where the solid soil column is formed. To make allowance for the water required to saturate the soil, 1,050 cc of water is added to every fifty grams of soil. A special cylinder is made which, when filled entirely with soil and hydrometer in it, will contain 1,050 of water, and thus the necessity of having to measure the water every time is eliminated. An ordinary 1,000 cc cylinder may also be used by making a mark of the proper volume.

The method may appear empirical, but it really gives quite absolute results. The results it yields are е also absolutely comparable for different soils. For instance, the rate of settling of soil particles is governed largely by their size. This being the case, then the amount of material staying in suspension at any given time has about the same average size of particles for the different soils. The hydrometer, when floating, is governed entirely by physical laws without any outside factors entering or any personal element entering into it. Its readings, therefore, are quite accurate.

Since the hydrometer method gives absolutely comparable results for the different soils, and since the

results show a very close relationship with the results of the heat of wetting method, it probably means then that the heat of wetting method for determining the colloidal content of soils has been a correct method. Evidently, both methods tend to measure the same thing.

From all our present knowledge, it appears that the hydrometer method can be employed to determine the colloidal content of soils, quite accurately. The method is also very rapid, the colloidal content of more than three soils can be determined in less than one hour, using only one hydrometer.

The hydrometer can also be used to measure the rate of settling of soil particles from which a distributed curve should be worked out.

Referring once more to the dispersing machine there are two things that must be strictly guarded against, the first is that the cup must have the baffles or wires in it, and the second is that the paddle or button on the stirring rod tends to wear out in sandy soils. When it becomes flat it must be replaced, because in the flat condition it loses its stirring efficiency. With these two precautions to watch out for, it can be said that this machine is most wonderful for dispersing soils for any purpose. The detailed report of this work will appear in Soil Science shortly.

MICHIGAN AGRICULTURAL EXPERIMENT STATION, EAST LANSING

GEORGE J. BOUYOUCOS

SPECIAL ARTICLES

THE LIFE HISTORY OF TAPEWORMS OF THE GENUS MESOCESTOIDES

THE generic name Dithyridium Rudolphi, 1819, has been used by zoologists to designate agamic cestodes having an elongate body and containing an invaginated scolex which bears four suckers but lacks both hooks and a rostellum. These larval parasites have been reported from a variety of mammalian and nonmammalian hosts, in most cases in relation with the body cavity and its membranes and viscera. In one instance they have been reported from the voluntary muscles and the heart. Morphologically these larvæ appear to occupy a position intermediate between those of pseudophyllid and cyclophyllid cestodes, their general body shape resembling that of the former, whereas the scolex is suggestive of a cyclophyllid tapeworm.

Although there has been some speculation as to the relationship of these larvæ to known strobilate tapeworms, no conclusive experimental work designed to elucidate the ultimate development of Dithyridium

larvae has been published up to the present time.1 Neumann (1896), Ransom (1907) and some other investigators have been struck by the morphological similarity of the scolex of Dithyridium and that of the genus Meso cestoides parasitic in the intestine of various mammals and birds. Neumann appears to have been the first investigator who suggested a connection between Dithyridium and Mesocestoides. Unfortunately, that investigator postulated what appears to be an unsound biological hypothesis to account for this relationship and his experimental work designed to test his hypothesis is decidedly inconclusive, a fact which he himself recognized. Neumann was inclined to regard Dithyridium as an erratic, immature cestode (Mesocestoides) which succeeded in reaching the body cavity apparently as a result of perforating the stomach or intestinal wall or in some other manner and which was destined to perish in this location without completing its further development. He also postulated a direct life cycle for Mesocestoides and expressed the opinion that the ingestion of hexacanth embryos of this tapeworm by a suitable host probably results in the development of a mature strobilate tapeworm in the intestine.

Recent investigations by the present writer have shown Neumann's interpretation of Dithyridium to be erroneous. Not only have these parasites a typical larval organization, consisting of a simple unsegmented ribbon-shaped body and an invaginated head provided with four suckers, but in common with other infective larval tapeworms they are capable of reaching maturity in the small intestine of a suitable definitive host. When ingested by a susceptible host Dithyridium develops into a strobilate tapeworm belonging to the genus Mesocestoides. Dithyridium thus bears the same morphological and biological relationships to Mesocestoides as Sparganum bears to Diphyllobothrium and as Cysticercus bears to Tania.

Briefly stated, the writer succeeded in rearing Mesocestoides in dogs and cats as a result of feeding them Dithyridium obtained from the peritoneal cavity and lungs of a mongoose. As early as forty-six days after ingestion of Dithyridium, gravid segments of Mesocestoides were found in the feces of dogs which prior to experimental infection were ascertained to be free from cestodes. Fifty-one days after experimental ingestion of five live specimens of Dithyridium, five mature specimens of Meso cestoides were recovered from a cat at necropsy. Before ingesting the larvæ the cat was free from tapeworms so far as fecal examinations showed anything. As Meso cestoides

1 This manuscript was submitted for publication on April 8 and while it was in the hands of the editor Professor Henry published a paper (Rec. de méd. vét., v. ciii, no. 8, April 30, 1927) reporting experimental results essentially similar to those covered in this paper.

has never been found in native dogs and cats in the Eastern United States, it seems safe to assume that that no such worms were present.

On the basis of these experiments, which it is hoped will be supplemented by the results of additional feeding tests which are now in progress, it may be safely concluded that the definitive host becomes infected with Meso cestoides as a result of devouring a carcass or a portion of a carcass of an animal harboring Dithyridium and that the latter is not a tapeworm which has accidentally strayed from its course but is a true larva in a normal location in an intermediate host.

It still remains to be determined whether the hexacanth embryos contained in the egg capsule of each gravid proglottid of Meso cestoides are capable of infecting the intermediate host directly, as is known to be the case in cyclophyllid cestodes whose life histories have been determined, or whether the embryos undergo their earlier larval development in an invertebrate, intermediate host before they can metamorphose into infective larvæ in a vertebrate, intermediate host. The answer to this question must await the results of experiments which are now in progress.

While this investigation was in progress an abstract2 of a paper in Russian by Skrjabin came to the writer's attention. Among other references to Professor Skrjabin's recent work in helminthology was the statement that he had found that mice are the intermediate hosts of Mesocestoides lineatus. BENJAMIN SCHWARTZ

ZOOLOGICAL DIVISION, BUREAU OF

ANIMAL INDUSTRY, U. S. DEPARTMENT
OF AGRICULTURE

ACCLIMATIZATION OF BUFO TADPOLES TO

ETHYL AND METHYL ALCOHOLS1

THAT animals may become immune to toxic substances that ordinarily will destroy them is too well known to call for comment. Since the work of such pioneers as Sewall and Erlich a mass of information has been collected on this subject. Yet in one phase, at least, the experimental data are not consistent. Studies of the resistance that organisms exhibit towards alcohol after they have been immersed in a weak solution of it for some time have failed to produce uniform results. Daniel ('09) has made rather an extensive study of the effects of ethyl alcohol upon Stentor and Spirostomum, subjecting them for various periods of time to a weak solution of the alcohol, and then killing them along with controls in a stronger solution. In general he holds that the ani

2 Berl. tierarztl. Wchnschr., v. 42 (52), Dec. 24, 1926. 1 Contribution from the Department of Zoology, University of Michigan.

mals did become acclimated. The treated protozoa generally lived considerably longer than the controls. Yet of the two strains of Stentor employed, one, while given exactly the same treatment as the other, showed little or no indication of acclimatization and led the author to remark (p. 611), "the fact that in these experiments some strains show little or no capacity for becoming acclimatized to alcohol although tried for long periods of time and with refined methods makes is questionable whether acclimatization takes place so readily and to so high a degree as is commonly supposed." Bills,2 using Paramoecium and adopting a method similar to that of Daniel,3 maintains that he not only obtained no indication of acclimatization, but that the treated animals were even less resistant to alcohol than those that were untreated.

An attempt to find out whether Bufo tadpoles will become acclimated to ethyl and methyl alcohols led to the experiments presented below. The tadpoles were put in solutions of one per cent. and three fourths per cent. ethyl alcohol, and one per cent., one half per cent. and one fourth per cent. methyl alcohol for periods varying from three days to about three weeks. In addition a number were treated for five minutes each day for several days with an eight per cent. solution of ethyl alcohol, which brought about complete narcotization, and were then returned to water and allowed to recover. Finally all were tested for acclimatization by placing them along with controls into 11 1/9 per cent. methyl or 8 per cent. ethyl alcohol for 20 minutes, after which they were transferred to water and the number that recovered ascertained. The results, greatly abbreviated, are given in the accompanying table.

Examination of the table will show that 107 animals were subjected to weak methyl alcohol and later placed 2 Bills, C. E., "Some Effects of the Lower Alcohols on Paramoecium.'' Biol. Bull., vol. 47, pp. 253–264. 1924. 3 Daniel, J. F., "Adaptation and Immunity of the Lower Organisms to Ethyl Alcohol." Jour. Exp. Zool., VOL. 6, pp. 571-611. 1909.

for 20 minutes in a 11 1/9 per cent. solution of the same alcohol along with an equal number of controls, and that 43 of the treated animals recovered when they were transferred to water, while only 11 of the controls recovered. The table also shows that out of 207 tadpoles treated with ethyl alcohol, 102 recovered after having been subjected to an 8 per cent. solution of the alcohol for 20 minutes, and that only 44 out of a like number of controls recovered. These results seem to point unmistakably to an acclimatization.

Owing to the small number of animals used one can scarcely draw any conclusions as to the relative effects of the various solutions, and for this reason a detailed account of the experiments has not been given. The exact time required for acclimatization and the effect of one alcohol upon the ability of the tadpole to withstand another are also problems deserving of solution, but which the data at hand are too meager to solve. A more comprehensive set of experiments is contemplated, designed to throw light on these questions. HARRY THOMAS FOLGER

UNIVERSITY OF MICHIGAN

THE AMERICAN ASSOCIATION FOR THE ADVANCEMENT OF SCIENCE THE SECOND NASHVILLE MEETING OF THE ASSOCIATION AND ASSOCIATED SOCIETIES

PREPARATIONS for the second Nashville meeting of the American Association for the Advancement of Science and associated societies, which will occur from December 26 to 31, are very well begun. Adequate lodging accommodations will be available, partly in hotels and partly in the Ward-Belmont and Peabody dormitories. The general headquarters will be the Andrew Jackson Hotel, in which will be the registration and news offices and the science exhibition. Headquarters for the societies that are to meet with Scientific the association will be announced later. sessions will be held mainly in the buildings of Van

derbilt University and of the Peabody College for Teachers.

Announcement may now be made of the local committees that are in charge of preliminary arrangements, which are constituted as follows:

General Chairman of Nashville Committees

W. S. Leathers, M.D., professor of preventive medicine and public health, Vanderbilt Medical School.

Committee on Arrangements

John W. Barton, chairman; vice-president of WardBelmont College.

H. A. Webb, secretary; professor of chemistry, George Peabody College.

L. C. Glenn, professor of geology, Vanderbilt University.

G. Canby Robinson, dean and professor of medicine, Vanderbilt Medical School.

J. T. McGill, professor emeritus of organic chemistry, Vanderbilt University.

A. E. Parkins, professor of geography, George Peabody College.

W. N. Porter, convention secretary of the Nashville Chamber of Commerce.

J. M. Breckenridge, professor of chemistry, Vanderbilt University.

G. R. Mayfield, associate professor of German, Vanderbilt University.

A. F. Ganier, assistant engineer, L. & N. Railroad. A. J. Didcoct, business manager, George Peabody College.

H. H. Shoulders, president of the Nashville Academy of Medicine.

E. L. Bishop, State Health Commissioner of Tennessee. A. W. Wright, assistant professor of pathology, Vanderbilt Medical School.

H. C. Weber, superintendent of the Nashville Public Schools.

Committee on Finance

John W. Barton, Chairman

Henry E. Colton

Charles M. McCabe

Committee on Meeting Places

A. E. Parkins, Chairman

F. J. Lewis

R. E. Baber

W. H. Hollinshead

W. D. Strayhorn

Committee on Hotels and Housing

W. N. Porter, Chairman

Lee J. Loventhal

S. C. Garrison

Committee on Exhibition

J. M. Breckenridge, Chairman

F. B. Dressler

E. W. Goodpasture

Committee on Local Transportation

A. F. Ganier, Chairman

J. P. W. Brown

W. F. Pond

Committee on Publicity and Non-technical Lectures

G. R. Mayfield, Chairman

H. A. Webb

T. J. Norner

T. H. Alexander
J. S. Stahlman, Jr.

Committee on Entertainment

A. W. Wright, Chairman
C. P. Connell

Mrs. A. B. Benedict
W. W. Carpenter
Alf Williams

Each section of the association has, as usual, a local representative to look after the needs of the organizations that are related to the section. A list of the names of the local representatives is given below.

Representatives for Sections

Section A (Mathematics), C. M. Sarratt.
Section B (Physics), C. R. Fountain.
Section C (Chemistry), L. J. Bircher.
Section D (Astronomy), James McClure.
Section E (Geology and Geography), L. C. Glenn.
Section F (Zoological Sciences), E. E. Reinke.
Section G (Botanical Sciences), J. M. Shaver.
Section H (Anthropology), W. D. Weatherford.
Section I (Psychology), Joseph Peterson.

Section K (Social and Economic Sciences), C. B. Duncan.

Section L (Historical and Philological Sciences), H. C. Sanborn.

Section M (Engineering), W. H. Schuerman.
Section N (Medical Sciences), P. D. Lamson.

Section O (Agriculture), K. C. Davis.

Section Q (Education), S. J. Phelps.. For organizations not related to any particular section, C. P. Connell.