amoebae, ciliates and flagellates—when so prepared can scarcely be distinguished from living material except for the absence of movement. Chloroplasts such as those found in Euglena and the algae retain their green color, and with a nearly closed condenser the finer details, particularly of the cilia or flagella, are shown very clearly. If permanent mounts are desired the usual staining methods may be applied, the various reagents being added to the material in the centrifuge tube. Iron haematoxylin gives splendid results after fixation with osmic acid, and with the exception of the destaining process with iron alum, the material need not be removed from the tube until it is in xylol. Chloroplasts do not seem to be affected by the various reagents, and material in balsam will remain green for weeks, after which the chloroplasts slowly fade. For finer details in such organisms it is better to bleach the chloroplasts with potassium permanganate, 1 per cent., and oxalic acid, 5 per cent., for about five minutes each before staining. Fixation in the osmic acid should be for from thirty minutes to an hour if permanent preparations are desired. This fixation, being cytoplasmic, offers an enlightening contrast to the more customary Schaudinn's fluid. DEPARTMENT OF ZOOLOGY, UNIVERSITY OF CALIFORNIA DAVID CAUSEY SPECIAL ARTICLES THE RELATION BETWEEN PROPERTIES AND CHEMICAL COMPOSITION OF SOIL COLLOIDS In previous publications of the Bureau of Soils it has been shown that the colloidal materials extracted from different soils may vary widely in adsorptive capacity, in heat of wetting and in chemical composition. During the past two years a series of different colloidal soil materials has been investigated for many other properties, such as size of particles, swelling, viscosity, electrical behavior and exchange of bases. The data, which are being prepared for publication, show that the colloidal materials extracted from different soils vary with respect to these properties also. It appears, as might be expected, that the various properties of the colloid are more or less related. A colloid, for instance, which undergoes a large volume change when wetted by water, usually shows a high heat of wetting and a high adsorptive capacity for ammonia gas. The properties of different soil colloids appear also to be related to their chemical composition. The major constituents of the soil colloidal material are silica, alumina and iron, and, in the case of many colloids, the properties vary fairly regularly with the contents of these major constituents as expressed by the molecular ratio of silica to alumina plus iron. An example of interrelationship between properties of the colloid and of parallelism between properties and chemical composition is shown in Table I. In this table a series of colloids extracted from different soils is arranged in ascending order of the ratio, silica to alumina plus iron. The heat (in small calories) evolved by these colloids on immersion in water and the ammonia gas adsorbed are shown in columns 3 and 4. In order to make the relationship more apparent and to bring out individual exceptions, the data of columns 2, 3 and 4 are expressed relatively in columns 5, 6 and 7. The lowest value in each series of determinations is placed at zero and the highest value at 100. By this procedure the different orders of magnitude of the three series of data are equalized; also the amplitudes of variation between the lowest and highest determinations are brought to 100 in each series. Most of the data in the table are taken from previous publications of this Bureau. 1, 2, 3 It is apparent that on the whole there is a close parallelism between the heats of wetting, ammonia. adsorptions and the silica ratios of the different colloids. Coefficients of correlation for these three series of values are as follows: heat of wetting with ammonia adsorption 0.99, heat of wetting with silica ratio 0.93 and ammonia adsorption with silica ratio 0.90. The high coefficients of correlation, together with the fact that correspondence between the lower relative values in columns 5, 6 and 7 is about as good as correspondence between the higher relative values, indicate that the three series of values are approximately straight line functions of one another. The correlation between heat of wetting and ammonia adsorption may be expected to hold fairly well for practically all soil colloids. But the correlation between heat of wetting (or ammonia adsorpSiO2 tion) and is probably subject to Al203 + Fe20 ̧ 1 Anderson, M. S., "The heat of wetting of soil colloids," Jour. Agr. Research, 28: 927-935 (1924). 2 Gile, P. L., et al., "Estimation of colloidal material in soil by adsorption," U. S. Dept. Agr. Bul. 1193 (1924). 3 Robinson, W. O., and Holmes, R. S., "The chemical composition of soil colloids," U. S. Dept. Agr. Bul. 1311 (1924). 4 Calculated according to the formula given by Tolley, H. R., and Mendum, S. W. "A method of testing farmmanagement and cost-of-production data for validity of conclusions," U. S. Dept. Agr. Circular 307 (1924). some marked exceptions. In the case of the Susquehanna subsoil colloid there is poor agreement between the heat of wetting and the silica ratio, although the agreement between heat of wetting and ammonia adsorption is very good. A correlation of the silica ratio with the heat of wetting or adsorption would not be expected to hold for colloids from peat soils, which are composed chiefly of organic matter and contain comparatively little silica, alumina and iron. Furthermore, colloids exceptionally low in silica and high in alumina and iron may as a class be exceptions to this correlation. For instance, a colloid containing only 15 per cent. of silica with a SiO2 ratio of 0.55 has recently been isolated Al2O3 + Fe203 from a deep tropical subsoil. The heat of wetting of this sample is 8 calories, or approximately the magnitude usually given by colloids having a silica ratio of about 1.9. The Sio, ratio is not the only expresAl2O3 + Fe203 sion of chemical composition that shows a parallelism to the properties of the colloid. It was pointed out in a recent bulletin of this Bureau5 that the colloids high in silica were usually low in alumina, high in monovalent and divalent bases and low in combined water. A fairly good correlation obtained between SiO2 SiO2 the ratio, and the ratio Al2O3 + Fe20,' CaO+Na2O for a series of soils. In view of these relationships, it follows that other chemical constituents beside the Robinson, W. O., and Holmes, R. S., p. 16, l. c. plastic clays having the higher ratios. A knowledge of the interrelationships of the properties of soil colloids and of the correlation between chemical composition and properties is of practical value in supplying a basis for predicting the general behavior of the colloids without extensive physical tests or complete chemical analyses. Similar relationships between properties and chemical composition doubtless obtain for the colloidal materials of ceramic clays and the recognition of these relations should be important in the ceramic industries. M. S. ANDERSON S. E. MATTSON DIVISION CHEMICAL INVESTIGATIONS WASHINGTON, D. C. CONTINUOUS REPRODUCTION OF MICROORGANISMS IN SYNTHETIC MEDIA THE controversies and work of Pasteur, von Liebig, Mayer and Nageli suggest that yeast may fail of 6 Joseph, H. F., and Hancock, J. S., "The composition and properties of clay,' "Trans. Chem. Soc. 125: 18881895 (1924). continuous cultivation in media affording an only source of nitrogen in ammonium salts. Growth and reproduction in a medium wholly synthetic has been generally considered impossible. Vitamine B or substances of the nature of "bios" are held necessary by various investigators for the continuous growth and reproduction of Saccharomyces cerevisiae. cane Fulmer, Nelson and coworkers1, 2, 3, 4 have reported continuous growth and reproduction in their medium E, composed of inorganic salts and sugar, and that yeast was subcultured when a synthetic product, methose, was substituted for cane sugar. Relatively large inoculations were used and single cell cultivation was not attempted. MacDonald and McCollum5 question the dependence of yeast on vitamine B or substances of the nature of "bios." In recent articles Robertson and Davis and Robertson conclude that yeast is incapable of synthesizing its own growth-stimulating substance or substances in their media, and that yeast cells to a large extent possess the power of "taking over" these essential food substances, and that growth in synthetic media is roughly proportional to the number of cells used for the original inoculation. They failed to obtain reproduction beyond the 12th or 15th generation (transfer). Willaman and Olsens stress the possibility of retention by the sugar of unanalyzable traces of "bios." Williams' maintains that vitamine B is necessary for the continuous growth of yeast. We have employed the medium E base of Fulmer and Nelson, Robertson and Davis medium and Nageli solution. Special emphasis was laid on the purity of the chemicals and cleanliness of the glassware and precautions taken to destroy any vitamine B that might be adsorbed. For energy sources we have employed synthetic methose and succinic acid and also distilled glycerol (280° C.) and 7-day hot 95 per cent. alcohol continuously extracted dextrose. Methose, first synthesized by Loew,10 was prepared from formaldehyde by the catalytic action of lead, MgO and MgSO, using CO2 and K2HPO to precipitate the salts. 2 4 Single cell cultivation was carried out in the following manner: Direct microscopic examination was made of nutrient silicic acid gel plates smeared with a culture that had grown in the liquid synthetic medium 1 Jour. Am. Chem. Soc., 1921, 43, p. 186. 4 Jour. Biol. Chem., 1923, 57, p. 397. for several weeks; single cells were marked, and after growth, transfers were made into the liquid medium. Since then cultures have been transferred on the average every 2 or 3 days for longer than 5 months. The use of Nageli solution was abandoned in favor of medium E. Robertson and Davis medium in our hands has not afforded continuous reproduction of our cultures of Saccharomyces cerevisiae when used at 30° C. Medium E base at 30° C. 1° and succinic acid, methose, glycerol or dextrose have afforded continuous growth and reproduction of the following pure cultures: 14 races of Saccharomyces cerevisiae, 1 Torula rosea, 1 Torula liquefaciens, 1 Oospora lactis, 1 Saccharomyces ellipsoideus. Two cultures of cerevisiae failed to adapt themselves and were lost. Aeration greatly assisted liquid culturing. Heretofore results, apparently, have depended upon the use of 1 race of Saccharomyces cerevisiae, or 1 species of yeast giving rise to discrepancies and to results not applicable to generalization. 2 The same four energy sources in a base of K2HPO̟ 2 gm, MgSO, 0.1 gm, Fe, Cl, trace, (NH4)2 SO, 2gm (omitted in growth of nitrogen-fixing bacteria), CaCl, 0.1 gm and water 1 liter, have been employed in a study of bacterial vitamine requirements. The following organisms, subcultured by using an inoculum equivalent to the amount of a straight needle transfer from liquid medium, have been continuously cultured in this liquid medium base, utilizing at least three of the four energy sources: Escherichia coli, Aerobacter aerogenes, Proteus vulgaris, Pseudomonas fluorescens, Encapsulatus pfeifferi, Pseudomonas cyanogena, Bacillus megatherium, Bacillus mycoides, Bacillus subtilis, Serratia marcescens, Azotobacter chroococcum, Rhizobium leguminosarum. The essential presence of vitamine B or substances of the nature of "bios" in the medium for growth and reproduction of certain yeasts and bacteria, notably Azotobacter chroococcum, has not manifested itself in our work unless such substance or substances were synthesized during the synthesis of methose and succinic acid, two entirely different processes; and failed to be extracted from the dextrose and did distil over with the glycerol. It appears reasonable to conclude in the light of our present knowledge that certain yeasts, torulae and bacteria may be continuously cultured in a medium wholly synthetic and that no addition of vitamine B or substances of the nature of "bios" is necessary. If such substances are necessary for the growth and reproduction of these organisms, they are metabolized. MASSACHUSETTS AGRICULTURAL EXPERIMENT STATION, AMHERST, MASSACHUSETTS C. H. WERKMAN University and Educational Notes The Etiology of Canine Distemper: ROBERT G. Scientific Apparatus and Laboratory Methods: The Ultra-Violet Microscope as Employed by Barnard: DR. W. G. MARQUETTE Special Articles: The Hydrophilic Effect of Ions on Agar and Protoplasmic Components: DR. D. T. MACDOUGAL and B. L. CLARKE The American Chemical Society: Division of Biological Chemistry: DR. R. J. ANDERSON Science News 117 121 127 128 130 JOHN MASON CLARKE (1857-1925) WITH the passing of John Mason Clarke, of Albany, on May 29, 1925, the world has lost not only one of its leading paleontologists, but one of its great men of all science. No paleontologist excelled him in discernment of the morphology of invertebrate Paleozoic fossils or in knowledge of the Devonian of North and South America; no philosopher has ever seen more clearly the lessons that these fossils teach or expressed them in more beautiful diction. Clarke was born in the beautiful lake resort of Canandaigua, New York, on April 15, 1857. He was of old American stock, with the best of traditions. His father, Noah Turner Clarke, one of the pioneers of Naples, New York, and for fifty years teacher and principal in the academy at Canandaigua, was a descendant of the William Clarke who settled at Dorchester, Massachusetts, in 1663, and became later one of the founders of Northampton. His greatgrandfather was a member of the Continental Congress and fought throughout the Revolutionary War. His mother was Laura Mason Merrill, of Castleton, Vermont, a descendant of the Mayflower Company, and of Governor Jonathan Trumbull, of Connecticut. Clarke's love for nature was inborn, and from his earliest boyhood he was interested in the rocks around his home. His first geology in school he got from his father, who then sent him in 1873 to Amherst, where he came under the inspiration of that devoted teacher, B. K. Emerson. He was given the bachelor's degree in 1877, at the age of twenty. The following two years he assisted his father at the Canandaigua Academy, teaching Latin, mathematics and geology, using Dana's text-book in the last-named subject. In 1879-1880 he returned to Amherst as assistant to Emerson. During the school year 1880-1881, he taught in the Free Academy at Utica, where James D. Dana and G. H. Williams had preceded him. Through Emerson's efforts he was in 1881 appointed to teach geology and mineralogy at Smith College, holding this position until the close of the school year 1883. He was then given leave of absence to study toward a doctorate at Göttingen, under Professor von Koenen, and here he spent parts of two years. Returning to Smith in October, 1884, he remained there until the spring of 1885, when he became lecturer on geology, zoology and German at the Massachusetts Agricultural College. Then followed some months of waiting, spent at Canandaigua, where he continued to work on the Upper Devonian (mainly the Naples fauna), a study begun in the summer of 1877 and intended as his dissertation at Göttingen. Out of employment, he appealed for work to James Hall, whom he had known since 1878. His persistence was rewarded when, on January 2, 1886, he became assistant to the man who was then the master paleontologist of the country. From that day until his death, Clarke was connected with the Geological Survey of New York, rising to the position of state paleontologist in 1898, and in 1904 to that of state geologist and paleontologist and director of the state museum and of the science division of the education department. From 1894 on he was also professor of geology and mineralogy at the Rensselaer Polytechnic Institute in Troy. Clarke is survived by his wife, formerly Mrs. Fannie V. Bosler, of Philadelphia; by Noah T. Clarke, a son by his first wife, who was Mrs. Emma Sill, of Albany;, by two stepdaughters, Mrs. Edith (Sill) Humphrey and Miss Marie Bosler, and a stepson, Mr. Frank N. Sill. Of his brothers and sisters there remain Miss Clara Mason Clarke, who, with Mr. S. Merrill Clarke, a former editor of the New York Sun, is still living at Canandaigua; Rev. Lorenzo Mason Clarke, pastor of the First Presbyterian Church in Brooklyn; and Mr. William B. Clarke, managing editor of the Baltimore American. Clarke had a brilliant, alert and well-trained mind. He was elegant in manner and dress and eloquent in speech. As a hard worker he quickly became a prodigious producer of excellent paleontologic and stratigraphic results. Ambitious, perhaps unduly suspicious at times, strong in likes and dislikes, he was also quick-tempered, though he usually had all these traits under good control. In temperament he was a lover of the worth-while and beautiful in nature and in art, and these inborn qualities, with his wide experience, enhanced his ability and eloquence and made him a collector of antique ceramics and furniture and historian of the fisher-folk of Quebec. The same qualities also are reflected in the unusual character of the splendid museum which he developed. After five summers' work in the field, Clarke began to show results, and his first papers appeared in 1882. They have to do with a rare living molluscan genus, and with rare Crustacea, phyllocarids and barnacles from the New York Devonian. Arthropods were, therefore, his first love among fossils, and they always had for him a dominating interest. In these papers he burst upon the scientific world, as it were, as a full-fledged descriptive paleontologist, since they show nothing of the beginner; even then he wrote well in a clear and direct fashion that, however, as yet showed none of the quaintness of phrase-making, love of strange words and power of embellishment and atmosphere so characteristic of his later writings. With Clarke's appointment to the New York Survey, his career as a paleontologist and stratigrapher was assured, and from his head and hand there came a continuous stream of the best kind of geologic publications, the great bulk of which were issued by his native state. As yet there is no completed list of his works, but Nickles's "Geologic Literature of North America" gives 192 titles. He must have to his credit more than 250 notes, papers and books, but even this statement does not indicate the volume of his work. A provisional tabulation shows upward of 9,000 pages of printed matter, in which he is godfather to 125 new genera and 865 new species. Clarke was born on Devonian rocks, and they ever remained the magnet of his endeavors. "The work of a geologist is preeminently what his environment makes it." The strongest pulls were those exerted by the Devonian of New York, southeastern Quebec and Brazil, but he was also attracted by that of Germany, Maryland, Falkland and Argentina. At least one half and probably three fourths of his total output has to do with the paleontology, stratigraphy and mapping of this period. He long ago became one of the two greatest world authorities on the Devonian, the other being Emanuel Kayser, of Germany. Clarke's study of the Upper Devonian faunas of Iberg in that country was written at Göttingen while a student of Von Koenen, and it was at this time that he became acquainted with Kayser. His loyalty to these two teachers of his is shown in his contributions to their Festschriften: "Evidences of a Coblenzian invasion in the Devonic of eastern North America" to that of Von Koenen in 1907, and to that of Kayser eight years later, "Conceptions regarding the American Devonic." The milestones in Clarke's scientific career as shown in his writings are twelve in number. Four of these have to do with stratigraphy and faunal studies (1, 3, 5, 6), three with the morphology of fossils (2, 4, 8), three with the philosophy of fossils (7, 9, 11) and two with history (10, 11). It is not possible here adequately to analyze the significance of these works, and all that can be done is to list them. They are as follows: (1) The Hercynian question (1889, 1891). (2) An introduction to the study of the genera of Paleozoic Brachiopoda (with Hall) (1893-1894). (3) The stratigraphic and faunal relations of the Oneonta, Ithaca and Portage groups in central New York (1897). |