Studies by negative staining on the structure of collagen fibrils in normal and lathyritic rats

Summary Electron microscope studies on collagen from rat-tail tendon using the negative staining technique indicate the presence of fine filaments 15–30 Å in diameter within the fibres. The banding of the fibrils was only slightly affected by aminoacetylnitrile bisulphate, but an increased amount of fine fibrous material was present in preparations from experimental animals. It is suggested that this material represents a soluble form of collagen which is known to predominate after administration of the drug. Despite the fact that this would be a chemically abnormal collagen, its structure by electron microscopy corresponds remarkably well with the form suggested from X-ray diffraction and physico-chemical studies on normal soluble collagen.The author would like to thank Mr. J. Clements for technical assistance and Mr. R. Thomas (Dental School, Bristol) for discussion on the effects of aminoacetylnitriles in rats.     

A phasic-tonic proprioceptor in the telson of the crayfish Procambarus clarki (Girard)

Summary A proprioceptor in the telson of the crayfish Procambarus clarki was found, which is made up of about five units. These show range fractionation, i.e. different threshold distributions and their response to bending of the telson has a transient and a stationary component. The peak frequencies reached during the period of the transient component were shown to increase with increasing bending velocity and had — with the exception of one case — the highest values when extension (contrary to flexion) was imposed. The position characteristic discharge frequencies of the stationary component and their variation with different telson positions were considerably smaller. The receptor signals movement and position to the central nervous system and is therefore called a phasictonic one.I am grateful to Prof. Dr. T. H. Bullock for his hospitality and interest in this work and also want to thank Mr. John W. Thorson for many constructive discussions. This work was aided by grants from the U.S. Public Health Service, National Science Foundation and Office of Naval Research to Prof. Dr. T. H. Bullock.     

Metabolic interactions between restraint stress and <Emphasis Type="SmallCaps">l</Emphasis>-lysine: The effect on urea cycle components

Summary.  We studied the effects of l-lysine on wrap-restraint stress-induced changes in ureagenesis. An exposure to wrap-restraint stress did not affect the plasma concentration of l-lysine, but did decrease plasma urea and arginine. Oral l-lysine (1 g/kg) blocked the effect of stress on ureagenesis, and enhanced the effect of stress on l-arginine. No influence of l-lysine were found in controls. The results imply a stress-specific, ureagenesis-stimulating effect of l-lysine, and suggest an increased requirement for l-arginine during the above conditions. Received December 9, 2002 Accepted January 21, 2003 Published online April 3, 2003 Acknowledgement Authors thank Dr. M. Miura (Ajinomoto Co.) for his help with amino acid analysis and Dr. T. Kimura (Ajinomoto Co.) for discussions on amino acid metabolism. Authors' address: Dr. M. Smriga, Ajinomoto Co. Inc., Institute of Life Sciences, 1-1 Suzuki-cho, 210-8681 Kawasaki, Japan, Fax +81-44-210-5893, E-mail: miroslav_smriga@ajinomoto.com Abbreviations: Arg, l-arginine; Orn, l-ornithine; Lys, l-lysine; p.o., oral; WRS, wrap-restraint stress     

Aerobic dissimilation of d-ribulose by yeasts

Aerobic dissimilation ofd-ribulose by various genera and species of yeasts was examined. Most strains tested utilizedd-ribulose fairly well, andd-arabitol was accumulated in the fermented broth but ribitol was not found. Torulopsis famata ATCC 20214,T.mannitofaciens CBS 5981 andT.versatilis CBS 1752 producedd-arabitol with a yield of 26 to 67% of the sugar used. Extracellular and intracellular formation of pentitol fromd-ribulose were compared with those fromd-xylulose.We wish to express our sincerest thanks to Prof. K. Arima and Prof. Y. Ikeda of the University of Tokyo for their kind guidance. We also wish to thank Dr. M. Mogi and Dr. N. Iguchi of this Institute for their encouragement and Mr. K. Kouchi for his technical assistance.     

Stem cell renewal and duration of spermatogonial cycle in the goldhamster

Summary The duration of the cycle of the seminiferous epithelium of the hamster is estimated to be 9.0 days. The duration of the stages was also determined.The stem cells were found to be daughter cells of the A₃ spermatogonia. This confirms the hypothesis that in general stem cells for the next spermatogonial cycle arise on the moment of morphological differentiation of the A spermatogonia.The author wishes to thank Prof. Dr. M. T. Jansen and Dr. M. F. Kramer for helpfull discussions and Mr. J. G. van Essen for technical assistance.     

Further evidence for the proposed way of spermatogonial stem cell renewal in the rat and the mouse

Summary By means of ³H-thymidine and autoradiography it could be established that in rats and mice the A₁, A₂ and A₃ spermatogonia do not give rise to a significant number of stem cells.The number of A₀ spermatogonia was found to be circa 20% of the number of A₀+A₁ spermatogonia in the rat and circa 10% in the mouse.The author wishes to thank Prof. Dr. M. T. Jansen and Dr. M. F. Kramer for helpful discussions and Mr. J. G. van Essen for technical assistance.     

The fine structure of muscle in a marine turbellarian

Summary The fine structure of the myofibers of Notoplana acticola as studied by electron microscopy indicates that they are composed of thick myofilaments about 200 Å wide with tapering ends and thin myofilaments about 50 Å wide, arranged alongside each other parallel to the long axis of the cell. There is no orderly transverse arrangement of filaments; instead they appear staggered in the fiber. In cross sections 6 to 10 thin filaments form an orbit around one thick filament with possible cross-linkage between the two types of filaments.Dense bodies are associated with the sarcolemma and with the sarcoplasmic reticulum, and appear to serve as attachments for the thin filaments. Dense bodies are compared to elements forming a fragmented Z-disc.Mitochondria, situated in the periphery or the center of fibers, are associated with granules interpreted as glycogen.The sarcoplasmic reticulum consists of: sacs or cisternae in close proximity to the sarcolemma, longitudinal tubular elements between and parallel to the myofilaments, and a tubular network around the filaments. There is no well-defined sarcolemmal-derived transverse tubule system as described in striated muscles. It is hypothesized that in these muscles, the functional equivalent of the T system may be the area of sarcolemma in contact with the cisternae of the sarcoplasmic reticulum.This work was supported by Grant No. GM 10292 from the U. S. Public Health Service to Professor Richard M. Eakin, Department of Zoology at the University of California, Berkeley, USA, where this investigation was conducted during the author's sabbatical leave of absence from the University of Illinois.I wish to thank Professor Eakin for valuable discussions and for his kind hospitality in extending the facilities of his laboratory and the use of the electron microscope to me, and the John Simon Guggenheim Memorial Foundation for the Fellowship which I held during 1964–65.     

The fine structure of the kinetochore of a mammalian cell in vitro

The chromosomes of Chinese hamster cells were examined with the electron microscope and the following observations were made concerning the structure and organization of the kinetochore. — The kinetochore consists of a dense core 200–300 Å in diameter surrounded hy a less dense zone 200–600 Å wide. The dense core consists of a pair of axial fibrils 50–80 Å in diameter which may be coiled together in a cohelical manner. The less dense zone about the axial elements is composed of numerous microfibrils which loop out at right angles to the axial fibrils. Together the structures comprise a lampbrush-like filament which extends along the surface of each chromatid. Some sections suggested that two such filaments may be present on each chromatid. The fine structure of kinetochores associated with spindle filaments was essentially the same as those free of filaments. The structure and organization of the kinetochore of these mammalian cells was compared to that of lampbrush chromosomes of certain amphibian oöcytes, dipteran polytene chromosome puffs, and the synaptinemal complex seen during meiotic prophase.The authors also wish to thank Dr. Arthur Cole of the Department of Physics for the use of his electron microscope facilities and for his helpful criticism.     

Cilia and other surface structures of the trochophore of Harmothoë imbricata (Polychaeta)

Summary Ciliary aggregations occur as the prototroch, neurotroch, apical system and as tufts associated with the eyes and superficial glands. The major collection of cilia is the locomotory organ or prototroch that runs around the equatorial plane of the larva. This band is composed of four contiguous rows of cells, the two medial rows bearing the long locomotory cilia. The cilia occur in clumps, with several clumps arising from each prototroch cell while both the main cells contribute to each clump. The central filaments of these cilia are orientated at right angles to the long axis of the clump, the direction of ciliary beat being at right angles to the progression of the metachronal wave along the prototroch. The neurotroch, extending from the mouth to the posterior pole of the larva, beats away from the mouth. The rate of beating is rapid, and the cilia are short. The apical area of the larva is bordered by five single lines of compound cilia that surround a few stiff cilia. All the cilia beat occasionally. A further line of cilia, the akrotroch, exists at a position halfway between the apical area and the prototroch on the same side as the mouth. These cilia beat towards the prototroch. Some of these cilia are associated with sets of glandular openings. The fine structure of the glands and cuticle is described. The glands are small mucous glands that open via a projecting pore which is encircled by rings of microvilli. They often occur in groups of four or in pairs. The cuticle is similar to that described previously for adult polychaetes.This work was started under a Science Research Council (U.K.) grant (B/SR/1871) for a Research Assistantship to Dr. M. S. Laverack and grateful acknowledgement is made for this. We would like to thank Dr. A. Boyde for all his advice and use of apparatus. The scanning electron microscope used in this study was provided by a Science Research Council (U. K.) grant to Dr. Boyde. We would like to thank Mrs. J. Parkes for photographic assistance.     

Ultrastructure of transitional epithelium of man

Summary Blocks of human normal renal pelvis and ureter obtained at the time of surgery were fixed in glutaraldehyde and osmium with or without ruthenium red, for electron microscopic observations. The transitional epithelium is arranged in three cell layers: basal, intermediate and superficial. All epithelial cells show numerous microvilli and contain the characteristic vesicles of transitional epithelium, bundles of cytoplasmic filaments, microtubules and numerous free ribosomes. The epithelial extracellular compartment is notably large and appears as an intricate, tridimensional network of canaliculi and cisternae which are wider in the intermediate and superficial layers and in which microvilli and cytoplasmic folds of vicinal cells are often attached or interdigitated. At these sites there are desmosomes.The surface of all transitional epithelial cells is covered by a fibrillar mucous coat which is more developed at the plasmalemma of the free border of luminal cells in which microvilli are also seen. Ruthenium red stains selectively the plasmalemma and the mucous coat of the free surface of the epithelium, indicating the presence of an acid polysaccharide. With this technic (Luft, 1965), it is observed, radiating from the plasmalemma, branching filaments which measure 100 Å in diameter forming a zone of varying density which is about 400 m wide and which corresponds, at the light microscopic level, to the luminal border of the transitional epithelial cells in which a sialomucin has been identified. The slender filaments have a beaded appearance. At the free border, superficial cells are attached by functional complexes in which tight junctions seal the epithelial intercellular space, which is opened at the level of the basement membrane where only desmosomes are observed.The ultrastructure of human transitional epithelium of urinary tract resembles the duct cells of the salt gland of certain marine birds (Fawcett, 1962) and the amphibian epidermis (Farquhar and Palade, 1965) in which there are active processes of transport. The mucous surface coat, selectively stained by the ruthenium red, contains a sialomucin (Monis and Dorfman, 1965, 1967).The ultrastructure and histochemistry of the mucous fluffy coat of man transitional epithelium and the observations of Porter and Tamm (1955), on the ultrastructure of preparations of the Tamm and Horsfall mucoprotein (1952) are bases for suggesting that transitional epithelium of urinary tract of man is the site of biosynthesis of certain urinary mucoids. Present investigations are directed to obtain evidence to substantiate this hypothesis.General Abbreviations B basal cell - E exfoliating cell - I intermediate cell - L lumen - S superficial cell - SC surface coat - bm basement membrane - ci cell infolding - d desmosome (macula adhaerens) - f fibroblast - fi cytoplasmic filaments - is intercellular space - jc junctional complex - ly lysosome - lym lymphocyte - mt microtubules - m mitochondria - mv microvilli - n nucleus - r ribosomes - rv round vesicle - zo zonula occludens - za zonula adherens Dr. Monis wishes to thank Dr. E. De Robertis for the use of the electron microscope facilities of the Instituto de Anatomía General y Embriologia, Facultad de Medicina, Universidad de Buenos Aires. — Prof. E. Trabucco and Dr. R. J. Borzone (Cátedra de Clinica Genitourinaria de la Facultad de Medicina, Universidad de Buenos Aires) generously supplied the specimens which were the bases of this study. — Thanks are due to Mrs. A. M. Novara and Mrs. Defilippi-Novoa for efficient technical help and to Miss Rosa Gentile for secretarial assistance. Photomicrography by Mr. M. A. Saenz.Dr. Zambrano is investigator (CNICT).     

Ultrastructural features of adult human tendon

Summary A variety of human tendons have been studied at the electron microscope level. The fibers of these tendons are composed of collagen fibrils that average 1,750 Å and 600 Å in diameter. A third population that measures 100 Å in diameter may represent immature collagen or filaments that are incorporated into tendon elastic fibers. The larger collagen fibrils vary in ratio with respect to one another, and are connected by interfibrillar bridges which in some cases appear to extend through the substance of the fibril. The collagen fibrils of the paratenon are less-well organized than those of the tendon proper and average 600 Å in diameter. Tendons that exhibit the property of lateral stretch (plantaris and palmaris) were compared at the ultrastructural level with tendons that do not have this property. No differences between the two tendon types could be determined in normal or spread preparations, indicating that the differences in physical characteristics are a result of fiber rather than fibril organization.Supported by Edward G. Schlieder Foundation GrantThe authors wish to thank Mrs. Janell Buck and Mrs. Eunice Schwartz for their excellent technical and secretarial assistance, and Mr. Garbis Kerimian for his excellent photographic work     

Control of stem-gall of coriander by fungicides

Summary The stem-gall caused byProtomyces macrosporus Ung. is a common disease of coriander which is an important spice crop of India and other countries. For the first time, it has been possible to obtain at least a partial field control of this disease, through seed treatment with thiram at the dose of 0.25 kg per 100 kg of seed. There are indications that better control is possible by combining seed and soil treatments with thiram. Seed treatment with TCNA — an experimental fungicide — may prove to be effective at a dose of 0.5 kg per 100 kg of seed.The authors are grateful to Dr.N. K. A. Rao, Dean, College of Agriculture and Dr.R. L. Paliwal, Director of Experiment Station, for their help. The Junior authors thank U. S. Agency for International Development (University of Illinois) for the award of graduate traineeships.     

On the composition of the nucleolus with special reference to its filamentous structure

Summary Different staining procedures, various digestion methods and autoradiographic techniques were employed to study the structure and composition of the nucleolus and of the nucleolonema, after unmasking the latter by adenosine treatment. The presence of DNA, RNA, protein and lipid in these structures has been shown. It has been demonstrated that the filamentous structure within the nucleolus — the nucleolonema— has a core of DNA, around which RNA and protein have accumulated. The structure of the nucleolonema suggests that it is in a highly active state, in synthesizing ribosomal RNA and protein.We take the opportunity to express our gratefulness to the Director, Prof. Dr. Hans Lettré, for providing facilities to work in this Institute. We like to thank our other colleagues, particularly Dr. N. Paweletz, for their valuable help during the course of the investigations.     

On the glycocalyx,the external coat of the plasma membrane,of some secretory cells

Summary The free surface of epithelial cells of secretory organs (human placenta, lactating mammary gland of the rat, choroid plexus of man and rat) and of the accessory organs of the genital tract of the male rat is characterized by a plasmalemmal differentiation named glycocalyx or surface mucous coat. This structure is built up by filamentous or globular substructures.Two main ultrastructural types of the glyeocalyx were observed: 1) The filamentous type such as in the rat epididymis, which resembles the cat intestinal glyeocalyx (Ito, 1965) and that one of human transitional epithelium (Monis and Zambrano, 1968), and 2) The globular type, as observed in the lumen of the lactating mammary gland of the rat.Sialic acid was demonstrated histochemically in the luminal glyeocalyx of all organs studied. In addition, the glyeocalyx of acinar cells of the lactating mammary gland contains sulfate and phosphate groups which were identified by histochemical technics, using enzymatic digestion procedures, suggesting the chemical heterogeneity of this glyeocalyx.Present investigations follow the working hypothesis that the complex carbohydrates of glycocalyces become part of the product of activity of secreting cells.We thank Mr. Luis Iwakawa, Miss Silvia Falcón, Miss Elsa M. Orgnero for technical help, Miss Graciela Aliaga for secretarial assistance. Photography by Mr. H. Magnani. Dr. Hugo F. Carrer cooperated in the initial stages of this investigation.The authors acknowledge the use of the electron microscope of the Department of Pathology, Córdoba University Medical School, for which they thank Prof. E. Mosquera and Dr. E. Hliba. Dr. Hliba photographed picture number 4.     

Quantitative electron microscopic investigations of mineral nucleation in collagen

Summary It has been previously shown that the distances between the nuclei within the collagen bundles of mineralizing tissues were in good agreement with the repeat distances of the cross-banding pattern of collagen, which supports the assumption that the distances between the mineral deposits reflect to a good approximation the distances between nucleation centres on the collagen macromolecule. However, the lateral separation of the nuclei were significantly higher than the distances between close-packed triple helices.Recently a new model of collagen aggregation has been proposed in which the smallest morphological units are subfibrils (Ø approx. 39 Å) packed in tetragonal array. This led us to measure once again the lateral separation between a) close-packed calcium phosphate needles lying in bundles at (1) the mineralizing front of mantle dentine and (2) at the mineralizing front of rat tail bone, and b) between the uranyl-lead nuclei produced in the staining of rat tail tendon.The mean lateral distances separating these nuclei fell within the range of 39–47 Å, which is a little higher than the distances of 39 Å which separate the microholes between the subfibrils in the tetragonal packing model, which are regarded as the likely sites of nucleation. If, however, it is assumed that the forces generated during mineralization can cause the collagen fibres to swell, then the lateral separation of the nuclei and the distances between the microholes would correspond very closely.We thank the Deutsche Forschungsgemeinschaft for financial support. We thank Prof. Dr. K. Heckmann and Dr. U. Mays, Dept. of Zoology, Münster, for allowing us to use their Siemens-Elmiskop 101 sponsored by Stiftung Volkswagenwerk, and Frau Dr. Weichan, Applikationslabor Siemens, Berlin, for performing the tilting experiments at their Siemens-Elmiskop 102. We thank Fräulein Ute Sporman for valuable technical help.     

Comparative immunochemical studies with antisera to sheep prolactin and bovine growth hormone on anterior pituitaries of ox,sheep, rats and mice

Summary Rabbit antisera to sheep prolactin and bovine growth hormone were used in the indirect fluorescent antibody technique on cryostat sections of anterior pituitaries of sheep, ox, rats and mice. It is demonstrated that in sheep and ox prolactin and growth hormone are manufactured by different acidophilic pituitary cells. Though the antisera do not precipitate the analogous hormones of rats and mice in gel diffusion tests, evidence is given for the specificity of the cross-reaction of the antisera with the analogous murine hormones in situ as found with the fluorescent antibody technique.We are grateful to Dr. J. D. H. Homan of Organon, Oss (The Netherlands) for the supply of bovine growth hormone and for kindly giving us the information concerning this preparation.We should like to thank Dr. F. J. A. Prop for the prolactin assays, Dr. H. G. Kwa for providing the mouse pituitary tumours and Dr. L. M. Boot for the mouse pituitary isograft in the kidney, Mrs. J. J. Geiger-Koedijk for the conventional staining of pituitary sections, and Mr. J. van der Kamp for the photography.     

Fine structural relation between the Sertoli cell and the differentiating spermatid in the human testis

Summary The structural relationship between the Sertoli cell and the developing spermatid was studied with the electron microscope. In the contact area of the Sertoli cell with the anterior part of the developing spermatid, a filamentous structure is observed. This structure consists of fine tubular filaments about 100 Å in diameter associated with dense material. The functional significance of the structure is discussed.Supported by Grant HD-00593-05 of National Institutes of Health, United States Public Health Service. The author is indebted to Dr. T. Katayama, Department of Urology, Chiba University, for supplying the materials.     

The organization of the substantia gelatinosa rolandi in the cat lumbosacral spinal cord

Summary The organization of the substantia gelatinosa and adjacent lamina III in cat lumbo-sacral spinal cord has been studied by light and electron microscopical techniques in normal cord and following dorsal root section.The substantia gelatinosa (lamina II of Rexed) is characterized by bundles of small, non-myelinated axons, principally oriented longitudinally. The substantia gelatinosa cells are small, spindle shaped, with a cytoplasm generally devoid of Nissl substance. There are extensive axo-dendritic and axo-axonal contacts within the substantia gelatinosa and less frequent axo-somatic contacts.Larger marginal cells oriented horizontally on the surface of the substantia gelatinosa and containing Nissl substance are also seen.Lamina III is somewhat similar to the substantia gelatinosa, but lacks the complex bundles of non-myelinated axons.Following dorsal root section, heavy degeneration is seen by light and electron microscopy in lamina III, but is rarely seen in the substantia gelatinosa. It is concluded that the substantia gelatinosa and lamina III are distinct anatomically and therefore may differ functionally.The possible physiological role of the substantia gelatinosa is discussed.This work was supported by a Special Fellowship 2F11 NB 1140 02 NSRB from the National Institute of Neurological Diseases and Blindness, United States Public Health Service.The author is indebted to Dr. E. G.Gray for his excellent advice. I thank Dr. R. W. Guillery, Dr. L. E. Westeum and Dr. B. G. Cragg for their assistance, and Prof. J. Z. Young, F. R. S. for his kind suggestions. I also wish to thank Mr. S. Waterman for the photography.     

Some morphological and histochemical aspects of nemertean connective tissue

Summary The organization of the connective tissue system in three nemertine species, Amphiporus pulcher, Lineus bilineatus and Lineus ruber has been studied. Most attention has been paid to A. pulcher. Light microscopical, histochemical and electron microscopical methods have been employed.Three elements have been found and described: several types of free cells, filaments and ground substance. The filaments belong to the collagen family and form a supportive collagen skeleton in the animals. The ground substance is abundant in A. pulcher and is composed of protein and acid and neutral polysaccharides. The connective tissue cells have been classified in three groups, but intergrading between the cells, especially groups 1 and 3 is found. The connective tissue cells are highly polymorphic and often combine several functions in the same cell, e.g. synthesis of extracellular products, phagocytosis, pigment synthesis or uptake and a function as cellular material for regenerative processes.It is stressed that the connective tissue system probably forms a unity in the animals and no attempt has been made to make a rigid and presumably rather unnatural classification into various types.Comparative aspects of nemertine connective tissue have been discussed in relation to the patterns found in acoel, triclad and polyclad turbellarians. It is concluded that the nemertean connective tissue system still has features in common with turbellarian patterns, especially the one found in polyclads. However, the nemertine connective tissue system exhibits greater complexity than those found in turbellarians. The nemertine connective tissue system both shows continuity to the turbellarian organizations but also has features added so that it conforms with the patterns found in most groups of animals including vertebrates.The author is indebted to Professor G. Thorson and Dr. Gunnar Berg, The Marine Biological Laboratory, Elsinore, for supplying the animals. The efficient and conscientious assistance of Mrs. K. Bahnert and Miss Åse Madsen is greatly appreciated.     

Die Schwarzföhre im Lainzer Tiergarten bei Wien

Zusammenfassung Ich habe nachzuweisen versucht, daß die Schwarzföhre (Pinus nigraArnold) im Lainzer Tiergarten bei Wien nicht spontan ist. 1. Die Bestände enthalten durchwegs mittelalte oder jüngere, reihenweise aufgeforstete Bäume. Alte Überhälter fehlen vollständig. — 2. Natürlicher Nachwuchs fehlt fast vollständig, während er im eigentlichen P.-nigra-Gebiet an sonnigen Stellen öfters anzutreffen ist. F.Vierhapper (in verschiedenen Vorträgen und persönlichen Gesprächen) meint übrigens, daß die Schwarzkiefer auch in ihrem niederösterreichischen Hauptareal nur auf Felsen wirklich spontan sein dürfte, wie er sie bei Herkulesbad (Siebenbürgen) nur an Felsen beobachtet hat. — 3. Die Begleitflora ist nicht die in Niederösterreich für Pinus-nigra-Wälder charakteristische, sondern besteht aus Arten, wie sie auch in den Laubwäldern des Lainzer Tiergartens häufig sind. An manchen Stellen wachsen nitrophile Arten 25, wie Urtica dioica, Stellaria media, Cirsium arvense. Die normalen Pinus-nigra-Begleiter erreichen, soweit sie vorkommen, im allgemeinen einen geringen Deckungsgrad, die meisten wachsen in den dem niederösterreichischen Hauptareal der Schwarzkiefer zunächst gelegenen Teilen (Mauerwald und Fasselberg, Bestand 2 bis 5) 26. — 4.Seckendorff (30) erwähnt schon den k. k. Thiergarten als künstliches Vorkommen mit genauen Angaben über die Anpflanzungsverhältnisse 27. — 5. Damit stimmen auch die Angaben verschiedener Forstleute des Tiergartens überein, die sämtlich die Schwarzföhre für nicht ursprünglich halten und das Alter der heutigen Kulturen auf 30 bis 100 Jahre schätzen; die Kultur ist nach ihrer Angabe wegen des Lichtbedürfnisses der jungen Bäume nur auf Kahlschlag möglich.Allen, die mich bei dieser Arbeit unterstützt haben, sage ich hiermit meinen herzlichsten Dank: den Herren Regierungsrat Prof. Dr.August Ginzberger und Prof. Dr.Friedrich Vierhapper () für die freundliche Anregung und Ermutigung: für die Bestimmung und Revision von Pflanzen den Herren Oberst a. D. R.Berger, Grabensee (N.-Ö.) (Viola z. T.), Dr. H.Gartner, Graz (Cerastium), Prof. Dr. A.Gilli, Wien (Rubus sect. Eubatus), Kustos Dr. H.Handel-Mazzetti, Wien (Taraxacum), Regierungsrat Prof. Dr. A.Heimerl, Wien (Achillea z. T.), Pater E.Jacobi, Salzburg (Carex z. T.), Dr. F.Koppe, Bielefeld (Moose z. T.), Primarius Dr. E.Korb, Wien (Viola z. T.), Dozent Dr. V.Krajina, Prag (Festuca z. T.), Dr. H.Neumayer, Wien (Verschiedenes), Dr. K. H.Rechinger, Wien (Salix, Rumex sect. Lapathum), Regierungsrat K.Ronniger, Wien (Thymus, Galium z. T.), Professor Dr. K.Rubner, Tharandt i. Sa. (Epilobium), Prof. Dr. V.Schiffner, Wien (Moose z. T., Flechten), Dozentur. J.Zabocki, Krakau (Viola z. T.), Professor Dr. H.Zahn, Karlsruhe (Hieracium z. T.), ferner Herrn Dr. B.Fischer, Wien, der mir bei der mikroskopischen Untersuchung einiger Gräser behilflich war, den Herren Lehrer J.Fenzl, Ingenieur H.Schwarz und Direktor Dr. H.Steinbach (alle Wien) für Literaturangaben. — Durch wohlwollende Vermittlung des Herrn Reg.-Rat Prof. Dr.Erwin Janchen erhielt ich von Herrn HofratFranz Wojtech die Erlaubnis zum Arbeiten im Tiergarten. Ich danke weiters auf das Herzlichste dem Jagd- und Forstpersonal des Tiergartens für freundliches Entgegenkommen und bereitwillige Auskünfte. — Die p_H-Untersuchung der Bodenproben von 1931 wurde im geologischen Laboratorium der Hochschule für Bodenkultur ausgeführt, dessen Benützung mir Herr Prof. Dr.Leopold Kölbl freundlichst gestattete, und zwar mitMercks Universalindikator. Die Ablesungen wurden von mehreren Personen durchgeführt. — Die Proben von 1932 und 1933 wurden in der Landwirtschaftlichchemischen Bundesversuchsanstalt in Wien untersucht, und zwar das p_H mit demTrénel-Uhlschen elektrischen Azidimeter; dabei wurde zum Teil auch die Azidität in KCl gemessen (die Werte von 1931 beziehen sich nur auf H₂O). Ebendort wurde 1933 auch die Kalkbestimmung nach der Karbonatmethode durchgeführt. Meinen herzlichsten Dank sage ich hiemit dem Direktor der Anstalt, Herrn Ministerialrat Ing.Josef Scholz und dem übrigen wissenschaftlichen und technischen Anstaltspersonal.