Qie |, | Bay q * Tvar , SN ae % THE UNIVERSITY OF CHICAGO PRESS CHICAGO, ILLINOIS Agents THE CAMBRIDGE UNIVERSITY PRESS LONDON AND EDINBURGH THE MARUZEN- USHIKI-KAISHA TOKYO, OSAKA, KYOTO THE MISSION BOOK COMPANY SHANGHAI KARL W. HIERSEMANN LEIPZIG THE BOTANICAL GAZETTE EDITOR JOHN MERLE COULTER VOLUME LXIl JANUARY-JUNE 1916 WITH THIRTY-ONE PLATES AND SIXTY-SIX FIGURES ’ THE UNIVERSITY OF CHICAGO PRESS CHICAGO, ILLINOIS TABLE OF CONTENTS The action of Schumann rays on ore oma (with four figures) - - W. T. Bovie Western plant studies. III - - Aven Nelson and J. Francis Macbride A Mexican Aytonia. Contributions from the Hull Botanical Laboratory 211 fos eae I-IV and four figures) = - Anna M. Starr Notes on succession from ‘ine to oak - - - Barrington Moore . The pathology of ornamental plants - - -- Mel. T. Cook Origin and development of the lamellae in ae (with plates V-XII and six diagrams) - - Geo. F. Atkinson On the germination of the ea grains of — _ and other fruit trees - J. Adams The decrease of permeability produced bya anes- thetics (with six figures) - W.J.V.Osterhout On pairs of species (with twelve figures) - - Resinale Ruggles Gates Abscission in Mirabilis jalapa pe ki XIII and two figures)- - - - Francis E. Lloyd The development of the conceptacle in Fucus. ontributions from the Hull Botanical Lab- oratory 212 (with plates XIV-XVID- - - Mabel Lewis Roe A new method of separating fungi from protozoa and bacteria Nicholas Kopeloff, H. Clay Lint, and David A. Coleman Biochemical and physiological study of the rest in the tubers of Solanum tuberosum (with two figures) - - - - - CharlesO, Appleman Decay and soil toxins. Contributions from the ; Hull Botanical Laboratory 213 -— - - George B. Rigg Nuclear division of Spirogyra. II. Nuclear divi- sion in S. bellis (with plates XVITI-XX) - - Mabel L. Merriman The embryo sac of Richardia pans Kth, (with plates XXI-XXIII) es - - Margaret R. Michell Stangeria paradoxa. Contributions from the Hull Botanical Laboratory 214 hinge _— XXIV- XXVI and one figure) - - - Charles J. Chamberlain Vv PAGE vi CONTENTS . [VOLUME LXI Undescribed plants from Guatemala and other Central American Republics. XXXIX - - John Donnell Smith Notes on the anatomy of the young tuber of Ipo- moea Batatas Lam. (with eight figures) - Florence A. McCormick Xerofotic movements in leaves (with eight figures) - Frank C. Gates Physical properties of some toxic solutions George B. Rigg, H. L. Trumbull, and Mattie Lincoln Five undescribed species of Ravenelia - - - W. H. Long A study of the life history of Trillium cernuum L. (with plate XX VII) - 7 - Margaret Heatley The pomnseies of color changes in oxidase re- agents - G. B. Reed Reduction divisions in ‘the pollen mother cells of Allium tricoccum. Contributions from the Hull Botanical Laboratory 215 (with plates XXVIII-XXX and one figure) - - - - Mildred Nothnagel The vegetation of the Selkirks (with map) - - Charles Hugh Shaw ‘Studies in the genus Bidens. III. Contributions from the Hulll Botanical snes 216 trick plite AAR se - Earl E. Sherff The occurrence of bacteria in frozen soil vith two | gape: + - E. C. Harder The prothallia of Ophiaglosum slg vit four figures) —- - Norma E. Pfeiffer The measurement of oxidation potential and its significance in the — of oxidases — two figures) ae G. B. Reed BRIEFER ARTICLES— Edward Lee Greene (with portrait) - - - - J.N. Rose The pollination of Asclepias cryptoceras (with one PRI) 6 ee a ee Oe ee Edwin Payson Physical conditions in sphagnum bogs - -~ - George B. Rigg Chloroform as a cans solvent in the imbedding process - D. M. Moittier and W. J. G. Land Besseyosphaera, a new genus of the Volvocaceae - Walter R. Shaw A method for the —— of histological mate- rial em ee ee J. Ben Hill Bieceiacs cones of Larix (with one figure) = - J. E. Kirkwood Preparation of copy Seas Pe Pa PAGE VOLUME Lx]] CONTENTS The structure of the ae of A oer (with one figur Count Solms-Laubach (with Sand oe Charles René Zeiller (with portrait) - - - - CURRENT LITERATURE - - - - en For titles of book reviews see index under author’s name and reviews Papers noticed in ‘Notes for Students” are indexed under author’s name and subjects Agnes Chase 340 D. H. Scott 433 E.C. Jeffrey 528 75, 164, 258, 344, 435, 530 DATES OF PUBLICATION No. 1, January 15; No. 2, February 19; No. 3, March 15,; No. 4, April 18 . No. 5, May 15; No. 6, June 15 a i ERRATA Vou LX Sinensis 462, line 7 from bottom, for angle read angles 499, line 15 from top, for embryo read cotyledon VoL. LXI 52, line 21 from top, for under read upper 77, line 11 from bottom, for Beec. read Becc. 77, line 10 from bottom, for 291-410. pi. 20 read 391-410. 78, line 14 from top, for 1914 read 1913 78, line 20 from top, for 11:326-403 read 17: 326-403 78, line 20 from bottom, for Chamodora read Chamaedorea 78, line 12 from bottom, for Piricande read Piricauda 78, line 9 from bottom, for 1914 read 1913 78, line 7 from bottom, for Hendersonia read Hendersonina 79, line 8 from top, for Dirts read Diets 79, line 32 from top, for Crepyaceae read Cyperaceae 149, table I, line 3 from top, for 870 read 820 149, line 16 from bottom, for 870 read 820 149, line 3 from bottom, for new read net 158, line 12 from top, for absorption read adsorption 228, line 10 from top, for Parthenium read Parthenocissus 376, line 20. from top, for longae read longi 376, line 25 from top, for crenulatatus read crenulatus 385, line 16 from top, for eodum read eodem 385, line 31 from top, for laevilus read laevibus - 297, line 3 from top, for Cunninghamia Davidiana read Cunninghamia pls. 15-20 VOLUME LxI NUMBER 1 POs BOTANICAL GAZETTE FANUARY 1916 THE ACTION OF SCHUMANN RAYS ON LIVING ORGANISMS W.T. BoviE (WITH FOUR FIGURES) The effect of light upon organisms is a subject of steadily growing interest and importance. The work of recent years indicates that we may hope to discover the fundamental principles involved in the action of light on protoplasm more readily by turning attention to the shorter light waves than by continuing to investigate the action of the longer waves which occur in sunlight. The chief reason for this is that light of shorter wave lengths acts more rapidly and pro- duces chemical and structural changes in such a way that its action can be much more readily followed. While these changes may not be identical with those produced by light of longer wave lengths, it may be taken for granted that the knowledge gained by studying the effects of the shorter light waves will prove to be of the greatest assistance in explaining the action of the longer waves. The present paper is a report of some observations by the writer on the effects upon protoplasm of light in the Schumann region of the spectrum, the region containing wave lengths between 2000 and 1250 Angstrém units. This region of the spectrum is of particular interest because the light which it contains has a much more injurious action upon protoplasm than has the light of longer wave engt 2 BOTANICAL GAZETTE [JANUARY No previous investigations have been made of the effects upon protoplasm of light in this region of the spectrum.’ One reason for this is that the employment of Schumann rays presents many diffi- culties. A special technique is required, and sources of these rays suitable for biological investigations have been lacking. The inves- tigations on Schumann rays described in this paper were made possible by the kindness of Professor: THEODORE Lyman, who placed at the disposal of’ the writer the necessary apparatus and pointed out the methods by which the difficulties of technique might be surmounted. The effects of ultra-violet light upon a variety of organisms have been studied and an attempt has been made to follow as carefully as possible the changes produced in the protoplasm. The changes in structure have been followed by observing the organisms under the microscope during the action of the ultra-violet light. The comparative efficiency of waves of various lengths in producing these changes has been studied by a variety of methods. As previously stated, it has been found that Schumann light is much more injurious to protoplasm than any light heretofore reported. An exposure of only a few seconds to the light from a comparatively feeble source is sufficient, not only to bring about death, but also to cause a complete disorganization of the proto- plasm. It has further been found that the destructive action is not lessened when the organism is exposed while it is thoroughly desiccated and in a high vacuum. As will be pointed out later, this fact is significant, for it indicates the direction in which we must look for an explanation of the changes produced by these and other electromagnetic waves. While no record of previous investigations of the hinkouieal effects of Schumann rays has been found, it seems advisable to give a brief review of certain investigations relating to the biological effects of light of longer wave lengths. Taking sun baths for hygienic purposes is a very ancient and widespread practice. The heliosis and the insolatio were * BILLON-DAGUERRE (Compt. Rend. 149 and 150: 1909) claims to have sterilized liquids by the Schumann rays. He made no study of the biological effects of the rays, and, moreover, it is by no means certain that his results were due to the actos of Schumann rays. On this point see LyMANn (28). Tgr6] BOVIE—SCHUMANN RAYS 3 important ates of the public baths of the Greeks and the Romans. In the beginning of the nineteenth century VALLET (33) Soni a complete cure of a case of dropsy by exposing the patient to sun- light one hour each day for 14 days, and LOBEL (24) cured a case of amaurosis by focusing sunlight upon the diseased eye. LOBEL thought that the beneficial effects of the exposure were due, not only to the physical action of the heat and the light, but also to the chemical action of the sunlight. In 1858 Cuarcot (9) reported the experiences of two chenists who were using an electric arc for vitrifying certain materials. The electric current was obtained from a Bunsen pile of 20 elements. The experiment lasted one and one-half hours. The experimenters were 50cm. from the arc, and experienced no change in temperature, but their eyes pained them so severely the following evening and night that they were unable to sleep. The next day they had a painful erythema of the skin. CHARCOT cites other cases of electric light burn caused by an arc from a battery of 600 Bunsen elements: He concluded that the erythema was due to the chemical action of the light, and not due to the heat. The first impetus to a critical study of the destructive action of light came when the germ theory of disease had been thoroughly established and scientists had recognized the importance of dis- covering efficient methods of disinfection. In 1877 Downes and BiuntT (10) reported the results of their experiments on the effect of light upon bacteria and other organisms. They undertook an investigation to determine whether or not light has a deleterious effect upon bacteria. They exposed culture media contained in glass tubes to sunlight. They showed that light is inimical to and, under certain conditions, may wholly prevent the development of organisms which are prone to appear in culture media. The action is more energetic upon bacteria than upon mycelial fungi. The fitness of the substratum for growing bacteria is not impaired by insolation. By using colored screens they showed that the blue end of the spectrum is more active than the red end. In a second paper (11) they showed that light will kill organisms which are in distilled water, and organisms which are air-dried. They tried to 4 BOTANICAL GAZETTE [JANUARY approach the problem of the mechanism of the light action by studying the action of light upon organic substances. The study of the action of light upon oxalic acid showed that by insolation oxalic acid is decomposed into carbon dioxide, carbon monoxide, and water. They found that oxygen is necessary for this decom- position. Experiments were then conducted on the action of light upon ferments. They showed that light, in the presence of oxygen, destroys the power of yeast to ferment sugar. They had intended to make an exhaustive study of the action of light upon organic compounds, but CHASTAING preceded them, showing that many organic substances were oxidized by the light when in the presence of free oxygen. Ductavux (15) in 1885 studied the action of light upon the anthrax bacillus. He was the first to study the action of light upon pure cultures of bacteria. He found that the ability of the organ- isms to resist the action of the light varies with the species, with individuals within the species, and with the nature of the culture medium. In 1887 Roux (30) found that his culture media, when exposed to sunlight, became toxic to the spores of the anthrax bacillus. Ductaux had previously shown that carbohydrates are easily oxidized in sunlight. Roux concluded, therefore, that his culture media were rendered antiseptic by the oxidation of the carbohy- drates which they contained. Warp (34) in 1892 separated the action of the light upon the medium from the action of the light upon the organism by exposing the spores in a thin film on glass and then adding agar. The exposed spores were killed. In other experiments he first exposed the agar to the light, and then added it to thin films of unexposed spores on glass. The unexposed spores grew in the exposed agar. He attributed the action of the light to the destruction, in the pres- ence of oxygen, of fatty foods stored in the spores. WaArb in later papers (35, 36, 37) described experiments on the relative toxicity of the various parts of the spectrum. Instead of exposing culture tubes to various parts of the spectrum, as several observers had done before, he exposed a culture evenly charged with organisms (Bacillus anthrax and B. subtilis) to the spectrum, formed by a 1916] BOVIE—SCHUMANN RAYS 5 quartz prism, of the light from a carbon arc. He was unable to tell exactly where the effect began, but in general it began at the blue end of the green, reached a maximum in the violet end of the blue, and diminished again in the violet and ultra-violet. The action extended into the ultra-violet. The culture was cooled on ice during the exposure. WARD suggested that light from a naked arc might prove efficient in disinfecting hospital wards, railway carriages, or other places where rays can proceed directly to the organism. He pointed out that a study of the action of light upon cells might teach us much concerning sunburn, sun baths, etc. Thus far the use of light as an agent for disinfection had not proved practicable, and interest in the destructive effects of light was becoming purely academic, but the subject received a new impetus by the discovery of phototherapy. In 1871 two papers appeared in the Lancet, one by BARLOW (2), the other by WATERS (38), on the deleterious effects of light in the treatment of smallpox. In 1893 FrnsENn (16) published a paper in which he reviewed the work of CHARCOT, WmDMARK, and Hammer. A little later he pub- lished a second paper on the treatment of smallpox cases in the absence of the chemical rays (17). This paper was followed shortly by three others on the same theme, and later in the same year by a paper concerning the destructive action of chemical rays upon animal organisms (18). FrINsEN’s work, published in 1893, was entitled Negative phototherapy. In 1896 there was held in Copenhagen a meeting of university professors and influential laymen for the purpose of studying the value of light in the treatment of disease. At this meeting FINSEN read a paper entitled ““Om Anvendelse of koncentrerede, kemiske Lysstraaler i Medicinen” (Kopenhagen, 1896), which set forth what he called ‘‘positive phototherapy,” as opposed to his ‘negative phototherapy” of 1893. As a result of this meeting the ‘“ Finsen Medicinske Lysinstitut” was founded. The personnel of the insti- tute consisted of 7 doctors, a physicist, an electrician, and 33 nurses. The results of the research of the institute from 1900 to 1907 were published in the Mitteilungen of the institute. The basis of ‘positive phototherapy” is given by Bre, a member of the institute, in a paper published simultaneously in medical 6 BOTANICAL GAZETTE [JANUARY journals in England, America, Germany, and France (35 dy Sy Oy Ph The experimental basis of FINsEN’s phototherapy is (1) the bac- tericidal property of the chemical light waves; (2) the power of the chemical rays to produce erythema; (3) the power of the chemical rays to penetrate the skin. The bactericidal property of the chemi- cal rays had been demonstrated by previous workers. WipMARK had proved by experiment the fact, pointed out by CHARCOT 30 years before, that photoerythema is produced by the chemical rays of light and not by the heat rays. GOODNEFF and FINsEeN demon- strated the powers of chemical rays to penetrate the skin, by placing sealed glass tubes containing silver chloride under the skin of cats and of dogs and exposing to light. The silver chloride was black- ened. FINSEN also showed that light will penetrate bloodless tissue, but will not penetrate tissue containing blood. He placed strips of sensitive paper on one side of a man’s ear and allowed blue and violet rays of concentrated sunlight to fall upon the other side of the ear. After 5 minutes the sensitive paper was not affected, but if the blood was forced out by pressing the ear between glass plates, the paper was blackened in 20 seconds. In agreement with this is the fact that the spectrum obtained by passing light through an ear filled with blood consists of only a red stripe, while the spec- trum obtained by passing light through an ear made anemic con- sists of all colors. It is worth while to consider in some detail the method used _ in the practice of FINSEN’s phototherapy. A carbon arc, carrying 50-60 amperes, is used as a source of light. Previous to 1901 sun- light which had passed through a concentration apparatus was used for treating the patients. Its use was abandoned because, aside from the uncertainty of weather conditions, it was found that sunlight is not only weak in the extreme ultra-violet region (the thera- peutically effective part of the spectrum), but it contains an abun- dance of light in the blue-violet region. The blue-violet waves so tan the skin that after one or two treatments the deposit of pigment makes further treatment impossible. The carbon arc, on the other hand, emits light of shorter wave lengths than those found in sun- light. These short light waves have a marked action upon the surface layers of the skin. They destroy many of the epidermal bi Me eae aos WY yt aN Tt Od 1916] BOVIE—SCHUMANN RAYS | cells, including those which contain the pigment. The skin, there- fore, becomes more transparent with each successive exposure, and hence there is a continual increase in the penetration of the light. Experiments were made with light sources which emit a rela- tively greater amount of light in the extreme ultra-violet than is emitted by the carbon arc; but it was found that there was no in- crease in the therapeutic effects, while there was an undesirable increase in the amount of destruction of the epidermal cells (29). The therapeutically effective rays are those which have wave lengths between 4000 and 3220 Angstrém units. These rays, after passing through a layer of skin 4 mm. thick, have a strong destruc- tive action upon bacteria. Light of wave lengths shorter than 3220 Angstrém units has no action upon bacteria which lie beneath the surface of the skin (23). The light from the carbon arc is passed through a concentration apparatus provided with condensing lenses of quartz, and also with water filters for absorbing the heat rays. The area to be treated is made as nearly bloodless as possible and is exposed to the light for 1 hr. and 15 min. at intervals of 1-3 days. The local anemia is produced by pressing the area during the exposure with a quartz lens. In. certain skin diseases, notably Lupus vulgaris, the light treatment is so successful that out of 350 cases treated previous to 1899 there were none which did not show improvement, and only 5 which were not cured. The result is so certain and so constant that there is every reason to doubt the accuracy of the diagnosis of Lupus vulgaris when the method fails. Besides developing ‘positive phototherapy” to a high degree of perfection, the studies carried on at the Finsen Institute contributed a large amount of information to our general knowledge of the destructive action of light. The experiments of previous investi- gators were carefully repeated and their significance was critically discussed, while extended researches were made into new fields. . As pointed out by LOBEL long ago, the biological effects of expo- sure to light are the result of photochemical action. Hence if we are to obtain a clear understanding of the biological action of ultra- violet light, it will be necessary to consider some of the characteris- tics of photochemical reactions. 8 BOTANICAL GAZETTE [JANUARY Photochemical action necessitates light absorption, although all light absorption is not accompanied by photochemical action. Since, for substances in general, light absorption increases as the wave length decreases, chemical action also increases as the wave length decreases; and, as pointed out in the pioneer work of Downes and BLuntT, -the destructive action of light upon proto- plasm increases as the wave length decreases. There is evidence for the supposition that the chemical charac- ters of some of the elements are changed when they are acted on by ultra-violet light. For example, when oxygen is acted on by light of short wave length ozone is formed; that is, ozone is more stable in such oxygen than it is in ordinary oxygen. In passing, it may be pointed out that this fact is of particular interest to the biologist, for ozone is more opaque to short light waves than is molecular oxygen, and it seems that life on earth is possible only because the ozone formed in the upper layers of the atmosphere by the ultra-violet of sunlight serves as a light-filter and protects the organisms on the surface of the earth from these shorter and more destructive rays. Chlorine may be mentioned as another example. In this case, not only are the chemical characters of the atom changed, but according to TRAutTz (32) the specific heat as well. In consequence of the fundamental nature of the changes pro- duced by the light, it is often found that many compounds contain- ing the same element are photosensitive. For example, light affects many of the compounds containing silver. Protoplasm contains many photosensitive elements, and it is found that protoplasm and a large number of the substances elaborated by protoplasm (sugar, starch, cellulose, chitin, hair, rubber, etc.) are decomposed when exposed to ultra-violet light. The temperature coefficient of light reactions is very low. For photochemical reactions, therefore, temperature has but little influence upon the speed of the reaction. Photochemical changes may take place in dry materials or in a vacuum. The writer has found that the time required to kill spores of fungi was the same, whether the spores were exposed while in a very high vacuum or while in the air and turgid with imbibed water. This result is most 1916] BOVIE—SCHUMANN RAYS 9 surprising in view of what we know of biochemical reactions, all of which take place in aqueous media. DREYER and HANSSEN (14) showed that albumins and globulins were coagulated when exposed to ultra-violet light, and the writer (8), by an investigation of the temperature coefficient of the reac- tion, showed that light coagulation, like heat coagulation, involves two reactions: (1) a chemical change in the albumin and (2) the precipitation of the albumin. He showed that the first reaction has a very low and the second a high temperature coefficient. HeEnrI (19) determined the coefficient of absorption of egg white and found that there is a close parallelism between the absorption by the albumin of the various wave lengths and their destructive action. A very important phase of the biological effects of light is to be found in connection with the action of the so-called photodynamic substances. The reader is referred to a summary of this subject by TAPPEINER (31), as space does not permit a discussion of it here. The writer has found no published record of previous investi- gations on the visible effects of the Schumann rays upon proto- plasm. Several investigators, however, have made microscopic studies of the visible changes produced in protoplasm by light of longer wave lengths. For the most part such studies have dealt with the effects produced in the tissues of higher organisms, and secondary physiological changes have not been sharply distin- guished from the immediate effects of the light. DREYER (12, 13) and HERTEL (21, 22) have studied the visible effects of ultra-violet light upon unicellular organisms, but neither of these investigators used light which contained the Schumann rays. © In the writer’s investigations, described later, the visible effects of light containing the Schumann rays have been studied. The source of light was a hydrogen discharge tube similar to the one described by LyMAN (25). The tube had two compartments con- nected by the internal capillary D, fig. 1. This capillary had an internal diameter of about 3 mm. In each compartment there was a ring electrode (A) of aluminum. The discharge passing between the electrodes was compressed in the capillary D, thus becoming a source of light. The bottom of the tube was closed by the plate F; Io BOTANICAL GAZETTE [JANUARY the top was closed by a transparent fluorite plate EZ. The Schu- . ‘\ oO. r ~ Fic. 1.—Discharge tube used for generating Schumann rays A, ring electrodes of aluminum y B, C, terminals connecting with a source of high potential Ms M, F); D, capillary for the current density; E, fluorite window; F, glass window. mann rays were emitted through this fluorite plate. As will be seen from the figure, the tube was so designed that the internal capillary was brought as near the fluorite window as _ possible without excessive heating of the window. This arrangement made it possible to expose the organism very near to the source of light. The dis- charge tube was excited by a 3-kilowatt transformer manufactured by the Clapp Eastham Company. The transformer worked on a 110-volt alternating circuit of 60 cycles. A variable resistance in the primary circuit was adjusted so that about o.8 ampere flowed through the primary of the transformer. The current through the discharge tube was 16-18 milliamperes. No capacity, beyond that due to the leads, was in- cluded in the discharge tube circuit. The primary circuit of the trans- former was operated by a relay working on a battery circuit which was controlled by an ordinary telegraph key. The relay circuit had connected with it another circuit which moved the pens on a chronograph. From the chrono- graph record the exact length of any exposure could be determined. The use of the relay circuit and telegraph key made it possible to operate the dis- charge tube without the risk of coming in contact with lines carry- ing currents of higher voltages. This was important when the 1916) BOVIE—SCHUMANN RAYS II tube was used in connection with a compound microscope, for it was often desirable not to look away from the microscope while operating the discharge tube. The discharge tube was placed upright under the stage of a compound microscope, in the place usually occupied by the con- denser and other substage attachments, with the fluorite window flush with the upper surface of the microscope stage. When the discharge tube was in this position the microscope mirror could not be used. Hence it was necessary to illuminate the objects under observation by some other means. Various methods were em- ployed: an arc lamp was placed beneath the work table, and by means of mirrors and lenses a beam of parallel light was directed up through the discharge tube; or the objects were lighted from above, either by concentrating the light on the microscope stage with a condensing lens or by using a special vertical illuminating objective. The discharge tube was held by a mechanical support so arranged that by moving a lever the discharge tube moved down and away from the microscope stage. The regular substage attach- ments could then be swung back into operating position. The change from the discharge tube to the substage attachments or from the substage attachments to the discharge tube could be made very quickly, and without interrupting observations through the microscope. The Schumann region of the spectrum is a region of general absorption for most substances. But few solids are known which transmit even the longest Schumann waves (26). Air absorbs all except the longer waves, the absorption being due to the oxygen (27). Fluorite is the only substance known which transmits the entire Schumann spectrum. In fact, the Schumann spectrum extends in the direction of short wave lengths only as far as fluorite transmits. It is evident, therefore, that if we wish to expose organisms to the " entire Schumann spectrum we can have no substance other than fluorite between the organism and the source of light. Even air must be displaced by the more transparent fluorite. Occasionally the organisms were placed directly on the fluorite window of the discharge tube; more often a special slide was used. The special I2 BOTANICAL GAZETTE [JANUARY slide was a regular microscope slide with a hole 1.5 cm. in diameter bored through it. A disk of fluorite was cemented into the hole with its upper surface flush with the upper surface of the slide. This slide was held in the regular mechanical stage of the microscope and the fluorite window of the discharge tube was thus brought into contact with the fluorite disk in the slide. When the tube was excited for any great length of time it became hot, and sufficient heat was conducted to the microscope slide to vitiate the results. It was found, however, that the light was so destructive that during a single exposure of sufficient length to kill the organisms, the temperature did not increase more than 1° C. The discharge tube was moved away from the microscope slide immediately after each exposure. The temperature of the drop of water which contained the organisms was measured by means of a thermal junction made of copper and constantin. The sensitive- ness of the galvanometer used was such that, with these junctions, one division on its scale corresponded to of05C. The constant junction was kept packed in ice in a thermos bottle. The vari- able junction was flattened out very thin and was attached to a flexible support in such a manner that it could be placed beside the organisms under the cover glass. The junction was held in place on the slide by the capillary pressure of the cover slip, and was in the field of view of the microscope during the entire experiment. If the temperature of the drop of water was raised more than 1° C. by the exposure to the light, the experiment was discarded. The arrangement of the tube, slide, and thermal junction is shown in fig. 2. The length of time required for killing varied both with the species and with the individual organisms. In general, a small organism was killed more quickly than a large one. With a given light intensity, an exposure of several minutes was not sufficient to kill such organisms as rotifers and lumbricoid worms, while Sphaerella-like swarm spores, which contain both chlorophyll and an “eye spot,” were killed almost instantly. The swarm spores were killed so quickly that there was not sufficient change in tem- perature to be indicated by the thermal junction. In some of the experiments the intensity of the light was reduced until an exposure 1916] BOVIE—SCHUMANN RAYS 13 of 10 seconds was required to kill the swarm spores. Exposures of one second duration were then made at intervals of several seconds. It was found that the action of the Schumann rays is additive. The swarm spores were killed only when the total exposure equaled 1o seconds. Other organisms gave similar results. The fact that the action of the light is additive made it possible to interrupt the exposure from time to time, and to make a detailed study of the progress of the changes produced by the light. The protoplasm of the swarm spores which had been killed by the light had a granular appearance. Often some of the protoplasm was extruded from the cells and was rounded up into drops. The cells of a large Spiro- gyra of the crassa type were killed by an exposure of 45 seconds when the discharge tube was carrying 18 milli- amperes. The first visible change was the disappearance of the wavy margin of the ‘ Fic. 2.—Arrangement of apparatus for chlorophyll bands. This be- microscopic observation of the effects of gan on the side of the cell Schumann rays: A, discharge tube; B, micro- nearest the light. Later the ‘ope slide containing a fluorite window; C thermal junction; D, cover glass; E, micro- bands broke into isolated scope objective. rounded drops, each drop containing a pyrenoid. At the same time that the bands were breaking up, they became shorter and contracted around the nucleus. As they contracted, they moved away from the cell wall, pulling the protoplasm lying next to the wall out into threads of viscous appearance. The nucleus became swollen and distended. When an active amoeba was exposed to the light of the hydrogen discharge tube there was a momentary cessation of motion, fol- lowed by a withdrawal of the advancing pseudopodia. Locomotion in another direction began again at once, before the pseudopodia were entirely withdrawn. The extended pseudopodia often turned directly upward away from the light of the discharge tube, and 14 BOTANICAL GAZETTE [JANUARY usually a pseudopodium was sent upward from the upper surface of the body. This pseudopodium was often seen to flatten out against the cover slip. The nucleus moved up into the upper part of this pseudopodium. In some cases so much of the protoplasm flowed up into the pseudopodium that the amoeba became top- heavy and toppled over. One amoeba was seen to send up a pseu- dopodium, to fall over, and then to repeat the process three times before it was killed. These reactions are really negative photo- tropic responses, the amoeba moving upward away from the light. As the protoplasm flowed up into the vertical pseudopodium a thick hyaline ectoplasm was left below. The ectoplasm usually constituted the greater part of the lower half of the amoeba. Often the amount of ectoplasm increased until it nearly equaled the amount of endoplasm. In one case the cover glass was pressed down on an amoeba while in this condition, and the endoplasm and the ectoplasm separated and rounded up into separate drops. Under a magnification of 2200 diameters the ectoplasm showed a few small granules in Brownian motion, but showed no vacuoles. After a a prolonged exposure there was often a peculiar flowing of the — granular endoplasm out into the ectoplasm. It did not appear to be the same kind of motion that one observes in the regular stream- ing of the protoplasm, but it was not easy to say wherein the differ- _ ence lay. After this all motion ceased and the protoplasm appeared coagulated. Under a high magnification (2200 diameters) the pro- toplasm was seen to be filled with fine vacuoles which were SO numerous that it was converted into a fine froth. These vacuoles were not visible before the organism was exposed to the light. It often happened that only a part of an amoeba was killed; for example, in one case an amoeba which happened to be near a bit. of opaque substance when the exposure was made sent a pseudo- podium up on top of the opaque substance. The nucleus was next sent up, and then as much of the granular protoplasm as possible. The bit was not large enough to protect the whole organism, and 4 fringe of protoplasm (ectoplasm) extended beyond it all the way around. The exposure was continued until this fringe was killed. After the exposure, the unexposed part of the organism moved away, leaving the dead fringe behind. In another case the light BG a og Bie 1916], BOVIE—SCHUMANN RAYS 15 was allowed to act for a few seconds on an amoeba which was moving very rapidly across the field of the microscope. The -amoeba became quiet during the exposure. As soon as the light was turned off, motion was resumed, but only part of the amoeba moved away; a part of the protoplasm was coagulated and was left behind. The exposure was continued in this way, a few seconds at a time, killing a part of the amoeba at each exposure, until only the nucleus and a small mass of surrounding protoplasm remained alive. A final exposure killed this. The length of exposure neces- sary to bring about these changes varied from 30 to too seconds with the hydrogen discharge tube carrying 29 milliamperes. As previously stated, the entire exposure was not made at one time, but at intervals, so that the experiment often extended over an hour. The changes produced by the light could thus be more carefully observed. Infusoria are very quickly cytolyzed by the rapid vibrations of these ultra-violet rays. The nature of the cytolysis varies greatly with the species, and in some of the minor details it varies with the different individuals. The writer has observed three kinds of photocytolysis in ciliated infusoria: (1) a cytolysis which is accom- panied by the formation of vesicles on the surface; (2) a cytolysis in which some of the internal portions of the protoplasm coagulate; and (3) a cytolysis in which some protoplasm disintegrates directly. The first two types of cytolysis were observed in Colpoda-like forms, and the third type was observed in Stylonychia. 1. Cytolysis by the formation of vesicles——The cytolysis is, in general, like that of Paramoecium in distilled water, in weak alkali, and in 5 per cent alcohol, as described by WuLZzEN (39). Whena Colpoda-like infusorian is exposed to the light from the discharge tube carrying 18 milliamperes there is first an increase, then a decrease, in the rate of motion of the organism. Soon vesicles filled with a clear liquid begin to form on the surface of the animal. The infusorian loses its original shape and swims in circles. A vesicle may continue to grow until it is larger than the original organism, or it may increase in size for a short time and then slowly shrink and disappear. As one vesicle is shrinking, others may be forming at some other part of the surface of the organism. Ifthe exposure is 16 BOTANICAL GAZETTE [JANUARY not continued too long the vesicles may entirely disappear and the organism apparently recover. A longer exposure causes the inner wall which separates the organism from the vesicle to rupture and the protoplasm to flow out into the vesicle; while a still longer exposure may cause the outer wall of the vesicle to rupture, per- mitting the protoplasm to flow out into the surrounding water, with which it is miscible. Sometimes the protoplasm disorganizes and rounds up into drops before it flows into the vesicle. This type of photolysis requires a total exposure of about 30 seconds. 2. Cytolysis in which parts of the protoplasm coagulate.—In this type of cytolysis an exposure of 10 seconds causes small areas of the protoplasm to coagulate. The coagulated masses move to the side of the organism and are extruded at once. A longer exposure causes more masses of coagulum to form. As the exposure con- tinues, the masses of coagulum form faster than they are extruded. A swelling appears on one side of the body, which increases in size and then bursts, allowing the protoplasm to flow out into the sur- rounding water. 3. Cytolysis in which the protoplasm disintegrates directly —When Stylonychia is exposed to the light from a hydrogen discharge tube excited by a current of 18 milliamperes, the organism is stimulated and its rate of motion is increased. It then loses its power of coordination, moves about in circles for a time, and finally comes to rest with its cilia still vibrating. Suddenly the outer membrane breaks at some point and a little protoplasm squirts out. Then, starting from this point, a wave of disintegration passes over the organism, leaving the protoplasm in isolated rounded drops. The drops show surface tension against each other, and also against the fluid in which they lie; but a further exposure may cause some of them to unite. If the discharge tube is excited by a stronger current, 50-70 milliamperes, the cytolysis begins at once before the loss of coordination occurs. Cytolysis begins at the posterior end of the organism. The infusorian darts across the field, leaving behind it a trail of its cytolyzed protoplasm. It continues its motion until only a very small amount of the original proto- plasm remains intact, and this cytolyzes at the instant motion ceases. ise Phe 1916] BOVIE—SCHUMANN RAYS 17 When the dry spores of Monilia sp. are exposed to the light no visible change is observed. If, however, after exposure the spores are allowed to absorb water they become turgid, but their proto- plasm assumes a coarsely granular, coagulated appearance, which is quite different from the finely punctate appearance of turgid unex- posed spores. When turgid spores of Montlia are exposed to the light two kinds of changes are observed: either the protoplasm takes on a coagulated appearance, after which no further change is seen, or the spore wall suddenly bursts and some of the protoplasm squirts out with such force that the spore is driven backward by the reaction. The protoplasm, both outside and inside the spore wall, appears granular. Approximately 50 per cent of the turgid spores burst in this manner when exposed to the light. An exposure of 20 seconds, when the discharge tube is carrying 18 milliamperes, is required to cause the spores to burst. A similar squirting out of the protoplasm was observed in a Navicula-like diatom, and in the spores of certain water molds when they were exposed to the ght. The fact that the light acts directly upon the organism itself, and not indirectly through the formation of some toxic substance in the medium, was made evident in the experiments in which the drop containing the swarm spores was larger than the window of the discharge tube, so that a few of the spores which were on the outer edge of the drop were not exposed. Those swarm spores which were not exposed to the light were not killed, even though they were at the very edge of the illuminated area. When the exposure was over they often swam into the region where spores had been killed the instant before. As they entered this region they did not make any change either in the rate or in the direction of their motion. From this it may be concluded that the light did not produce any toxic substance in the solution.- This conclusion is further strength- ened by the fact that occasionally a swarm spore which was within the range of the light from the discharge tube was protected from the direct influence of the light by the shadow of some opaque material contained within the drop. No change which could be attributed to the action of the light was observed in such an indi- vidual. Again, the fact that the position of the dead swarm spores 18 BOTANICAL GAZETTE [JANUARY always marked out exactly the outline of the window of the dis- charge tube may be taken as evidence that no toxic substances were formed in the solution. The observations made on other species of organisms lead to the same conclusion, that the action of the light is on the organism itself. Notwithstanding the fact that the light was roi an exceed- ingly feeble source, the changes in the organisms were imme- diate. In the small swarm spores with thin transparent cell walls the changes appeared the instant the discharge tube was excited. It is evident that the Schumann rays are very destructive to proto- - plasm. The examples just given of the visible effects of these rays upon organisms are sufficient to make it apparent that we are deal- ing here with a powerful cytolytic agent, and one which warrants further study. The relation between the wave length and the destructive action of light in the Schumann region of the spectrum has not been pre- viously studied. For the longer light waves this relation has been investigated to some extent, as will appear from the brief summary which follows. Downes and Btunt, using colored screens, showed that blue light is more destructive to bacteria than red light. Warp, using a quartz prism, confirmed the results of Downers and Bunt, and showed that the killing power extends into the ultra-violet. Two papers appeared in 1905 on the bactericidal action of light, describing experiments in which not only the wave length but also the intensity of the light was measured. Bane spread the light of a carbon arc into a spectrum by means of quartz lenses and a quartz prism, and measured the relative destructive action of the various parts of the spectrum by determining the length of time it took in a given region of the spectrum to kill an organism (Bacillus pro- digiosus) growing on the surface of an agar plate. His results showed that, in general, as the wave length of the light decreases the destructive action increases, but that the curve is not uniform, showing a break in the region of wave length 3000 Angstrém units. In this region the light is several hundred times less destructive than in the regions on either side, so that the curve shows two maxima. The secondary maximum is in the region of wave length 3500 1916] BOVIE—SCHUMANN RAYS 19 Angstrém units. A measurement of the energy of the spectrum (which was made with a bolometer) showed that the amount of energy decreased with the decreasing wave length; but that in a region nearly coinciding with the region. in which the destructive action of the light fell off the amount of energy increased, so that, when the two curves, the energy curve and the destructive curve, are compared, the one is seen to be the inverse of the other. The depression in the destructive curve and the elevation in the energy curve do not quite coincide, but BANG attributed this to a slight shift in some part of his spectrograph. HERTEL (21) used quartz lenses and a quartz prism to form a spectrum of the light from various spark gaps. He measured, by means of a thermopile, the energy of the light of various wave lengths which he allowed to fall upon living tissues. He found that the destructive action of the light varies directly as the energy, and inversely as the wave length. He did not find the two maxima described by BANG. HENRI (19, 20) in 1912 measured the relative destructive action of light of various wave lengths. He used as sources of light a mercury vapor arc in quartz, and spark gaps with cadmium and magnesium terminals. The relative intensity of the light of various wave lengths was measured by the effect upon a photographic plate. He made use of screens for filtering out the various wave lengths. The efficiency of the screens was determined by spectrographic methods. He found that the destructive action of the light increases continuously as the wave length decreases. Henri did not find a secondary maximum at 3500 Angstrém units, as reported by Banc. With the exception of BANG, these investigators have agreed that, in the regions of the spectrum studied, the destructive action of light increases as the wave length decreases. None of their investigations have included the region of the spectrum lying below wave length 2000 Angstrim units. In the experiments described in this paper the relation between the wave length and the destructive action in the Schumann region has been studied. Because of.the small amount of energy in the Schumann rays, no attempt has been made to measure the intensity of the light of the various wave lengths. A knowledge of the suis 20 BOTANICAL GAZETTE [JANUARY relative intensity has been approximated from their effect on a photo- graphic plate. It is known that the spectrum from a hydrogen ~ discharge tube contains a number of bright lines in the neighbor- hood of wave length 1600 Angstrém units, while if the hydrogen is extremely pure there are no lines between wave lengths 2000 and 1675 Angstrém units. In this study the destructive action of light including the wave lengths in the region of 1600 Angstrém units has been compared with the destructive action of light from which these waves have been filtered out by means of screens. The hydrogen C. discharge tube previously described was | ‘ used as a source of light. Three ad different methods were used. 4 In the first method the hydrogen discharge tube was placed upright with — : the fluorite window above. The rock ~ salt screen A (fig. 3) was laid upon — the fluorite window. Glass plates were | | coated with nutrient agar and set aside — in a sterile closet until the agar became — oe ys air dry. Spores of Penicilliun were — relation between wave length Placed upon the agar surface, and the and the destructive action of plate C placed, spores downward, on Schumann rays: A, rock salt the ring support B. The lower surface — screen; B, brass ring; C, cover : wi. of the plate was about 0.05 mm. from 7 the salt screen. After the exposure, the plates were placed in Petri dishes lined with damp filter paper and the Petri dishes set in the incubator. The agar absorbed watet and the uninjured spores germinated. Exposures of various lengths were made, and the shortest expo sure which would kill determined. The amount of current flowing through the discharge tube was measured and kept constant during all the experiments. The rock salt screen cut out the light of wave lengths shorter than 1800 Angstrém units (26). Control experi- ments were made by removing the rock salt screen and laying in its place a screen of fluorite having the same thickness. The fluorite — was transparent to waves longer than 1250 Angstrom units. By — using the fluorite screen the distance between the spores and the — oe A = Se ae a ao rs tg16] source of light was kept constant. BOVIE—SCHUMANN RAYS 21 The short waves would have been absorbed by the air had it not been replaced by the more transparent fluorite. Spores of Cephalothecium roseum were not killed by an exposure of 60 seconds, and spores of a species of Monilia were not killed by an exposure of 420 seconds when the screen of rock salt was used, while the spores of both forms were killed by an exposure of 15 seconds when the screen of rock salt was replaced by the screen of fluorite. In the two other methods the apparatus shown in fig. 4 was used. A glass tube A, 31 cm. in diameter, was closed at one end with a glass stopper B which was ground in. The other end was closed by a brass ring C which had a fluorite disk D sealed into its center. The seal was made with De Khotenski cement. A side tube E connected the tube A with a mercury vacuum pump and a McLeod gauge. The tube was used in a vertical position. An upright brass tube F was cemented to the glass stopper. At its upper end it carried a platform H. The platform was a copper disk soldered to the head of a screw I which passed through a nut soldered to the top of the brass tube F. By turning the screw the distance be- tween the platform H and the fluorite window D could be regulated. A Fic. 4.—Chamber for study- ing the relation between wave length and the destructive action of the Schumann rays: A, glass tube; B, stopper; C, brass ring supporting fluorite window D; £, exhaust tube; F, adjustable support for the platform H; K, platinum hemisphere which is brazed to the brass plate L; M, rock salt screen supported by the brass pins NV; O, discharge tube. hemisphere K, 5 mm. in diameter, was pressed out of a polished platinum plate. plate L Its open side was brazed to a small piece of brass 22 BOTANICAL GAZETTE [JANUARY A disk of rock salt M with plane parallel faces had holes bored through it into which were inserted brass pins N, which served as legs. In operation, these parts were placed in the tube, as shown in the figure. The source of light was a hydrogen discharge tube, as shown at O. Its fluorite window was in contact with the fluorite window D. In one method the apparatus was used as Kien The glass stopper with its attached parts was removed from the tube, the platinum hemisphere sterilized in a flame, and then placed convex side upward upon the stage of a binocular dissecting microscope. Fungus spores were transferred to the top of the ere with a platinum needle. By means of the binocular mi rrange ment of the spores on the platinum hemisphere cduld be easily observed. After the spores were transferred to the dome a current of air blown through sterile cotton was allowed to play upon the hemisphere. All of the spores which were not in actual contact with the platinum were thus removed. This treatment gave a thin layer of spores quite evenly distributed over a small area at the very top of the hemisphere. The platinum hemisphere was now placed upon the platform H, and the screen M placed in position, the glass stopper B inserted and carefully turned until an air- tight joint was formed. The tube was then exhausted to about ©.00I mm. mercury pressure, and the exposure made. After the exposure, air was admitted into the tube and the stopper B removed. The platinum hemisphere with the exposed spores was again placed on the stage of the binocular microscope. A small drop of agar had been allowed to solidify on the under side of the cover slip of a van Tieghem cell. This cover slip was removed from the cell and brought over the spores on the platinum hemisphere. Then, while observation with the binocular microscope was being made, the cover slip was carefully lowered until the “hanging drop”’ of agar just touched the spores on the top of the hemisphere. The cover | slip was immediately lifted, taking the spores with it, and placed back on the ring of the van Tieghem cell. The cell was then set in an incubator. Because of the curved surface of the platinum hemisphere the spores were transferred to the agar without chan- ging their relative positions, and as the agar drop came in contact 1916] BOVIE—SCHUMANN RAYS 23 only with the spores on the top of the hemisphere, only those which had been directly exposed to the rays of light were transferred. The length of exposure required to kill the spores with and without the salt screen was determined. The results obtained with the spores of Trichothecium roseum are given in table I. TABLE I WITHOUT ROCK SALT SCREEN WITH ROCK SALT SCREEN : . Percentage of A : Percentage of Time of exposure in seconds | germination Time of exposure in seconds germination Oi ieri isles BOs ee a 20.0 eer ies a ere os ok 2.9 $90 5 in coceaweeek oes 2.0 } Pee Same cian eae 3.2 BOO. ga ee os 1.0 ya ea Neen i ots x.3 GOO ee a ee 0.0 BE ob 46S ie oles baw ahs Mee 0,0 22 ere are ee ee 9.90 OOPS eae ei ee 0.0 Se Ci cert ee ee 0.0 An unknown amount of light was reflected from the surface of the salt screen. In order to avoid this source of error, the experi- ments were repeated, and the length of exposure required for killing was determined first with the tube containing air at atmospheric pressure, and then with the tube evacuated. The distance from the top of the platinum hemisphere to the fluorite window D was 11cm. This gave a filtration of 1cm. of air. Lyman (27) has shown that an air filter 1 cm. thick cuts out all of the shortest Schumann rays. The results obtained with Trichothecium roseum are given in table II. TABLE II Time of exposure in seconds Conditions Results y Cam EU ree iii Baal et Vacuum Growth “ Sry ee ome e wasuen i BO ayers Soler ars 3 Dead BO er eee ae hay ee Air Growth OO pia ea a - wa 1S ER TE i EB et . iy BAO ee ee He BOO he rent ” Dead I was not able to kill the tan-colored spores of Penicillium brevicaule or the black spores of Stemphylium sp. (probably S. 24 BOTANICAL GAZETTE [JANUARY macrosporoidium). 'The Schumann rays have not sufficient pene- trating power to pass through the colored cell walls. By this method we were comparing the time required to kill spores in air with the time required to kill them in a vacuum, but preliminary experiments in which the hemisphere K was brought very close to the fluorite window D showed that the presence or absence of air makes no difference in the length of exposure required for killing. It should be pointed out that for these experiments organisms were selected which had very thin and transparent cell walls. It was impossible to obtain similar results with organisms with thick, dark-colored spore walls. The length of exposure required to kill dark-colored spores was so great that it is doubtful if the Schumann rays took any part in the killing. The light emitted from the fluorite window of the hydrogen dis- charge tube is much less destructive when the light waves of a length shorter than 1700 Angstrém units are filtered out. The results obtained by the three methods are comparable. The light is 15-20 times more destructive when it contains the short waves than when it does not. The significance of these figures lies in the fact that in the Schumann region, as in the regions of longer wave length, the destructive action of the light increases as the wave length decreases. Necessarily, this statement does not hold true for organisms protected by membranes which are opaque to the Schumann rays. Summary By a number of methods it has been shown that the action of the light is on the organism directly, and not indirectly through the formation of some toxic substance in the medium. It is a well-established fact that the Schumann region of the spectrum is a region in which nearly all substances have strong absorption bands. While no studies have been made upon the absorption of protoplasm in this region of the spectrum, un- doubtedly strong absorption does. occur. Gelatin, which is a much simpler substance than protoplasm, is so opaque to the rays that the ordinary photographic plate cannot be used in photographing the Schumann spectrum. Special plates, in which the silver salts 1916] BOVIE—SCHUMANN RAYS 25 are for the most part deposited on the surface of the gelatin, must be used. HENRI (19, 20) has shown that a very thin layer of egg white is opaque to ultra-violet waves between 3000 and 2000 Angstrém units in length, and that in this region the opacity increases as the wave length decreases. If the absorption coefficient of egg white can be applied to living protoplasm, and if the opacity of egg white con- tinues to increase with decreasing wave length as we pass from the region studied by HENRI into the Schumann region, then it is reason- able to suppose that the Schumann rays penetrated only a short dis- tance into the substance of the organism. The extreme destructive action of these rays is a result of the strong absorption. That the rays penetrate only a short distance into the substance of the organism is indicated by the observations made on amoebae, in which only a part of the protoplasm was killed by the exposure to the light. It may have been that the nucleus and the protoplasm which moved up into the vertical pseudopodium were well protected from the shortest waves of the Schumann rays by the thick layer of ectoplasm which remained below. Those parts of the proto- plasm which were on the side away from the source of light were killed by the longer, less active light waves only after a prolonged exposure. Again, in the experiments on Spirogyra, the visible changes always began on the side of the cell nearest the light. Fungus spores, with brown or tan coloring matter in their cell walls, even though the walls were thin, were not killed by a prolonged exposure to the light. The Schumann rays could not pass through the cell wall. ; Because of this strong absorption, the Schumann rays have a marked localized action which gives them a peculiar value for inves- tigations in the experimental morphology and physiology of the cell. In the experiments on the motile organisms, amoebae and infu- soria, it was seen that the Schumann rays have a stimulating effect, to which thé amoebae respond by drawing in the pseudopodia and assuming a spherical form, and to which the infusoria respond, first, by an increase in the rate of motion followed by a decrease, then by a loss of the power of coordination, and finally by the disintegration of the living substance. 26 BOTANICAL GAZETTE [JANUARY The examination of highly differentiated cells like those of Spirogyra has shown that the visible changes produced by the light are not the same in all protoplasmic structures. The change pro- | duced is often one which results in an alteration of the equilibrium of the water content of the protoplasm, as shown by the shrink- ing and swelling of various parts, by the bursting of spores, and by the miscibility with the surrounding water of the protoplasm of cytolyzed infusoria. As pointed out in a former paper (8), ultra-violet light causes certain chemical changes in egg albumen, changes which lead to a change in the time-temperature-coagulation curve. A study of the nature of these chemical changes has shown that they result in a decomposition of the albumen molecule. Preliminary experiments upon the effects of ultra-violet light on other protein bodies show a similar destructive action of the light. It would seem, therefore, that the stimulus of light is to be classed with those exciting stimuli which accelerate catabolic changes; and that using, as we have in these experiments, light with high vibration frequencies, we have been able within a short space of time and with no very great light intensity to’ carry the chemical changes through fatigue and death, and finally to a complete destruction and dissolution of the proto- plasm. The writer has found that spores dried in vacuo may be killed by ultra-violet light. This becomes understandable from experi- ments which the writer made, and which will be published later, which show that albumen and other proteins, dried in vacuo, are readily decomposed by ultra-violet light. The effect of these high- frequency electromagnetic vibrations on proteins is comparable to that of dry distillation at high temperature. These experiments suggest to us a mechanism of the action of ultra-violet light, and furnish a clue which, it is hoped, will explain the mechanism of all the effects of light on protoplasm, including those which are not injurious; for it is evident that if the decomposition of the protein molecule is not carried too far it may stimulate the cell without producing injury. A good example of this sort of stimulation is seen in artificial parthenogenesis, which is produced by substances the action of which kills the egg if allowed 1916] BOVIE—SCHUMANN RAYS 27 to go too far, but merely stimulates it if stopped at the right time. It is interesting to note that the photolyses previously described follow the photo-chemical-energy law first formulated by Tarzor, that the amount of chemical change is proportional to the product of the intensity times the length of exposure, or, if the intensity is constant, that the amount of chemical change is proportional to the length of exposure. It required the same total length of exposure to bring about cytolysis when the illumination was interrupted as when it was continuous. In the Schumann region of the spectrum, as in the regions of longer wave length, the destructive action of the light increases as the wave length decreases, and when we consider the very short exposure which was required for killing, notwithstanding the feeble source of light used, it is evident that the light of the Schumann region is much more destructive than the light of the regions of longer wave length. In other words, the curve representing the _ Telation between wave length and destructive action, which slopes upward in the régions of shorter wave lengths, continues into the Schumann region of the spectrum without changing its character. LABORATORY OF PLANT PHYSIOLOGY RVARD UNIVERSITY LITERATURE CITED 1. Banc, Uber die Verteilung bakterientétender Strahlen im Spektrum des Kohlenbogenlichtes. Mit. Fin. Med. Lichtinst. 9:164. 1905. 2. Bartow, On the exclusion of light in the treatment of smallpox. Lancet. 1871. 3- Bir, Finsen’s Phototherapy. Phila. Med. Jour. 1899. 4 , Finsen’s Phototherapie. Die Medicinische Woche. 1900. : ——_——-, Finsen’s Phototherapie. Therapeutische Monatshefte. 1900. , Professor N. R. Finsen’s Lichttherapie. Zeitsch. Riek teeiranayee und Arztliche Elektrotechnik. 1899. , Remarks on Finsen’s Phototherapy. British Med. Jour. Sept. 30. 9. 8. deve The temperature jpg ’ the coagulation caused by ultra- violet light. Science N.S. 372373. 9- Cuarcor, Erythéme produit par tactlon de la lumiére électrique. Compt. Rend. 10:63. 1858. + Downes and Brunt, Researches on the effect of light upon bacteria and other organisms. Proc. Roy. Soc. London 26:488. 1877. col ° 28 BOTANICAL GAZETTE [JANUARY 11. DownEs and Bunt, - influence of light on protoplasm. Proc. Roy. Soc. London 28: 199. -12. DREYER, Die Paes ae des Lichtes auf Amében. Mit. Fin. Med. Lichtinst. 4:81. 1903. , Untersuchungen iiber die Einwirkungen des Lichtes auf Infusorien. Mit. Fin. Med. Lichtinst. 7:98. 1904. 14. DREYER and Hanssen, Sur la coagulation des albumines par l’action de la lumiére ultra-violette et du radium. Compt. Rend. 145:234. 1907. 15. Ductaux, Influence de la lumiére de soleil sur la vitalité des germes de microbes. Compt. Rend. 100:119. 1885. 16. FINSEN, Om Lysets Indvirkninger paa Huden. Hospitalstidende. July 5. 1893. 17. , Uber die Pockenbehandlung mit Ausschliessung der chemischen Sirablen des Tageslichtes. Hospitalstidende. September 6. 1893. 18. , Om de kemiske Straalers skadelige Virkning paa den dyriske Organisme. Hospitalstidende. 121069. 1893. 19. Henri, Variation de pouvoir abiotique des rayons ultraviolets avec leur longueur d’onde. Compt. Rend. 1552315. 1912. 20. HENRI ef al., Etude quantitative de l’absorption des rayons ultraviolets par l’albumine d’ceuf et le serum. Compt. Rend. 733319. 1912. 21. Hertet, Uber physiologische Wirkung von Strahlen verschiedener Wellen- lange. Zeitschr. Allgem. Phys. 5:95. 1905. 22. ————, Uber die Einwirkung von Lichtstrahlen auf Zellteilungsprozessen. Teiteche Allgem. Phys. 53534. 1905. | 23. JANSEN, Untersuchungen iiber die Fahigkeit der baktericiden Lichtstrahlen durch die Haut zu dringen. Mit. Fin. “Med. Lichtinst. 4:37. 1903. 24. LésEeL, Wichtige Ansichten iiber die Beriicksichtigung der Insolation in mehreren Ubelseynformen vorziiglich in der Amourse, und iiber die Reali- sirung der Idee eines Sonnenbades. Jour. Prakt. Heilkunde 2:56. 1815 25. Lyman, The spectrum of hydrogen in the region of extremely short wave lengths. Mem. Amer. Acad. 13:125. 1906. 26. ————, The absorption of some ee for light of extremely short wave intia. Astrophys. Jour. 25:45. 27. ———, The absorption of _ sir ke light of very short wave lieth. Aniecalevs. Jour. 27287. 1 , The ge mee of peed by light of very short wave lengths. Wature 84:71. oO. 29. REYN ire ee und Methoden zur Lichtbehandlung. Mit. Fin. Med. Lichtirat. 10: 128. 30. Roux, De l’action - iis lumiére et de l’air.. Ann. Inst. Pasteur. 1887. v 31. TAPPEINER, Die Photodynamische Erscheinung (Sensibilisierung durch fluoreszierende Stoffe). Egeb. Phys. 8:698. 1909. 32. TrRAutz. (See review in Die Naturwissenschaften 1:38. 1913.) Zeitschr. f. Elektrochem. 18: 513.. 28. 1916] BOVIE—SCHUMANN RAYS 29 33- VALLET, Jour. Gen. Med. Chirurgie. 1814. 34. WarD, Experiments on the action of light on Bacillus anthracis. Proc. Roy. Soc. London 52:393. 1892. 35- , Further experiments on the action of light on Bacillus anthracis. Proc. Rie, Soc. London 53:23. 1893. 36. , The action of light on bacteria. Proc. Roy. Soc. London 54: 472. 1893. 37- , Further experiments on the action of light on Bacillus anthracis and the waters of the Thames. Proc. Roy. Soc. London 56:315. 1804. 38. Waters, On the action of light in smallpox. Lancet. 1871. 39- Wouzen, On the mechanism of cytolysis in Paramoecium. Quart. Jour. Exp. Physiol. 2: 293. 1909. WESTERN PLANT STUDIES. III AVEN NELSON AND J. FRANCIS MACBRIDE POLYPODIUM VULGARE L. var. hesperium (Maxon), n. comb.— P. hespertum Maxon, Proc. Biol. Soc. Wash. 13: 200. 1900.—The intermountain form with shorter, broader, and usually very obtuse pinnae. ISOETES OCCIDENTALIS Hend. var. Piperi (A. A. Eat.), n. South. —I. Piperi A. A. Eat. Fern Bull. 13:51. 1905; 2. Howellit Engelm. var. Piperi Clute, Fern Allies 258. 1905.—The velum broader and the spores larger with obtuse tubercles. Muhlenbergia setiglumis (Wats.), n. comb.—M. sylvatica Torr. var. setiglumis Wats. Bot. King Exped. 378. 1871.—Very closely allied to the eastern M. sylvatica Torr., but each confined to its own range. Streptopus streptopoides (Ledeb.), n. comb. ~ecins strepto- poides Ledeb. Fl. Ross. 4:128. 1852; Kruhsea Tilingiana Regel Nom. Mem. Soc. Nat. Mosc. 11:122. 1859; S. brevipes Baker, Jour. Linn. Soc. 14:592. 1875.—This form of species name is always to be regarded as unfortunate, but at the present time, at least, it must be used in cases like this. Majanthemum dilatatum (Wood), n. comb.— Unifolium bifo- lium DC. var. dilatatum Wood, Proc. Phil. Acad. 154. 1868.— The genus Majanthemum is one of the nomina conservanda of the international rules. The plant is well worthy of specific rank. Arenaria macra, n. n.— A. tenella Nutt. T. and G. Fl. 11:79. 1838, not Kit. in Schuet. Oestr. Fl. ed. II. 1:662. 1814, a valid species of Austria. Spergularia bracteata (Robinson), n. comb.—8S. salsuginea Fenzl. var. bracteata Robinson, Syn. Fl. 1: 251. 1897.—The bractlike upper leaves are very different in aspect from the apparently entirely Siberian S. salsuginea. DELPHINIUM Menzrestt DC. var.’ fulvum, n. var.—Pubes- cence, especially above, yellowish-villous and slightly viscid.— Eastern Oregon and adjacent Idaho. Botanical Gazette, vol. 61] [30 1916] NELSON & MACBRIDE—WESTERN PLANTS 31 Delphinium stachydeum (Gray), n. comb.—D. scopulorum Gray var. stachydeum Gray, Bor. Gaz. 12:52. 1887.—One of the most readily distinguished species of the group to which it belongs. Meconella linearis (Benth.), n. comb.—Platystigma linearis Benth. Trans. Hort. Soc. Il. 1:407. 1834; Hesperomecon lineare (Benth.) Greene, Pitt. 5:146. 1903.—GREENE (0p. cit.) has called attention to the earlier and valid Platystigma of RopeRT Brown. In our judgment, however, Hesperomecon Greene is not distinct from Meconella Nutt. Horkelia Tweedyi (Rydb.), n. comb.—Ivesia Tweedyi Rydb. N.A. FI. 22: 288. 1908.—This plant was long included in the nearly related but much more southern H. utahensis (Wats.) Rydb. It is consistently distinct from that species, however, and seems to be confined to Washington on the eastern slope of the Cascades. In making this transfer we would call attention to our remarks in Bor. Gaz. 55:375. 1913 on the fallacy of maintaining certain segre- gate genera in this group. Trifolium Kennedianum (McD.), n. comb.—T. involucratum Ortega var. Kennedianum McD. N.A. Trif. 56. 1910—The broad, equal, entire involucral teeth readily distinguish this plant. In the species to which it was referred, the .involucral teeth are some- times entire, but narrower and very unequal in length. CARDAMINE CORDIFOLIA Gray var. Lyallii (Wats.), n. comb.— C. Lyalli Wats. Proc. Am. Acad. 22:466. 1887; C. cordifolia Gray subspec. Lyallii (Wats.) O. E. Schulz, Engl. Bot. Jahrb. 32: 438. 1903.—ScHuLz is undoubtedly justified in no longer maintaining this plant as a species. We give it varietal rank that it may accord with those variations deemed unworthy of specific status, and then treated as varieties by most American botanists. CLARKIA and its near allies—In Bort. Gaz. 52:267. 1911, there were separated from Clarkia some species that are evi- dently aberrant in that genus. It is very doubtful whether the restoration of the genus Phaeostoma relieved a difficult situation. Granting that Phaeostoma has 8 fertile anthers while Clarkia has only 4, separating on this basis creates an equal difficulty between Godetia and Phaeostoma in that both have 8 stamens and the latter may have petals either clawed or not clawed. But the same is true 32 BOTANICAL GAZETTE [JANUARY of Godetia if G. biloba Wats. be left in the genus. This latter might be transferred to Phaeostoma but for its bilobed petals, or to Clarkia if judged by its aspect alone. The larger the series of specimens and the more species included in the study, the more probable it seems that unbroken series can be established running through the three genera on the following characteristics: 1. Stamens 4-8 and all alike or in two sets, the one gradually reduced in size and finally to sterility and extinction. 2. Petals from entire to deeply 2 or 3-lobed, and from sessile to long and narrowly clawed. It would not seem unwise to reduce all three to one genus but for the fact that to do so would again necessitate a number of new combinations. Pachylophus psammophilus, n. sp.—Wholly glabrous through- out, caulescent, branching near the base, usually 1 dm. or more high: leaves lanceolate, entire or slightly repand, acutish, each attenuate into a petiole with margins narrower than the midrib: calyx tube only twice as long as the narrow acute segments: petals white (drying pink), 2-3.5cm. long: capsules sessile, narrowly conical, somewhat curved and tapering gradually, 3—3.5 cm. long, not at all tuberculate, slightly angled. Plants growing in sand dunes in the vicinity of St. Anthony, Idaho. Very distinct in aspect and technical characters from its nearest relative, P. caes- pitosus (Nutt.) Raimann, of South Dakota. PERIDERIDIA Reichb. Handb. 219. 1837; Meisn. Genera 1:150. 1837; Endl. Gen. Pl. 792. 1838; Steudel, Nom. Bot. ed. II. 2:304. 1841.—Eulophus Nutt. in DC. Coll. Mem. 5:69. 1829, not Eulophus R. Br. in Bot. Reg. 573. 1821, in the English text. ROBERT BROWN in 1821 published his new orchidaceous genus Eulophus, and though he changed this to Eulophia in 1823, the earlier form of the word must, of course, be used. This necessi- tates, unfortunately, another name for the plants we have known so well as Eulophus Nutt. It may be questioned if REICHENBACH really published his genus in his Handbuch; certainly he makes no reference to a species, as stated in the Kew Index. The genus is given good descriptions by the authorities cited above, however; and STEUDEL publishes it with the species. The following new combinations, together with the type, are noted. 1916] NELSON & MACBRIDE—WESTERN PLANTS 33 PERIDERIDIA AMERICANA Reichb. ex Steudel, Nom. Bot. ed. II. 2:304. 1841; Eulophus americanus Nutt. in DC. Coll. Mem. 5:69. 1829. Perideridia Parishii (C. and R.), n. comb.—Eulophus Parishii C. and R. Rev. N.A. Umbell. 112. 1888. Perideridia Pringlei (C. and R.), n. comb.—Ewulophus Piac C. and R. op. cit. 113. Perideridia simplex (C. and R.), n. comb.— Eulophus simplex C. and R. Contrib. Nat. Herb. 7:112. 1900. Perideridia Bolanderi (Gray), n. comb.— Podosciadium Boland- ert Gray, Proc. Am. Acad. 7:346. 1868; Eulophus Bolanderi C. and R. Rev. N.A. Umbell. 112. 1888. Perideridia californica (Torr.), n. comb.—