摘要:

SYNOPSISSome changes in the structure of cotton fibre which accompany mercerization are illustrated. The familiar swelling, rounding out, and partial untwisting of the collapsed fibre into a more nearly rod‐like shape have been investigated with both the light and the electron microscope. Shrinkage and compacting of the primary‐wall network to provide a constricting casing about the fibre, crimping of the microfibrils of the secondary‐wall cellulose, and ultimate smoothing out of the wrinkled primary wall have been observed. A technique for expansion of the fibre wall into layers further demonstrates the altered structure of the cotton fibre after tension‐mercer

ISSN:0368-3974    

DOI:10.1111/j.1365-2818.1965.tb02103.x

出版商:Blackwell Publishing Ltd    

年代:1965

数据来源: WILEY

摘要:

SYNOPSISBacteria were examined with a Smith interference microscope using a half‐shade eyepiece and photomicrographs of their images were prepared. Microdensitometer traces on the negatives demonstrated conclusively that the method developed by Ross in 1957 to measure the thickness of bacteria was subject to systematic error. This error was eliminated by modifying the half‐shade eyepiece so that its comparison area was no larger than the image of a single bacterium; a critical comparison of this new method of measurement of phase change through small microscopic objects demonstrated its advantages over the other well‐established methods.Measurements of bacterial thickness obtained by this new method are markedly lower than those obtained by other interferometric methods; they are, however, still slightly higher (by a maximum of 30 p.c.) than the values obtained by measuring the widths of similar bacteria directly from the mid‐points of the diffraction fringes visible at the boundaries of the image. The work of Wolter and of Charman is discussed in the light of these f

ISSN:0368-3974    

DOI:10.1111/j.1365-2818.1965.tb02104.x

出版商:Blackwell Publishing Ltd    

年代:1965

数据来源: WILEY

摘要:

SYNOPSISUnder certain conditions the relationship between the optical‐path difference and the light intensity in an interference system is identical for both even field and interference fringes. This principle has been utilised to determine the absolute value of optical‐path differences in interference contrast (even field) for estimation of the dry‐mass concentration of tissue sections. A Leitz double‐beam interference microscope has been employed and the intensities were evaluated by photographic photometry. The method adopted consists of the following steps: (a) tissue sections are immersed in a medium which completely penetrates into the object; (b) the specimen is first examined in interference fringes using monochromatic light and a photograph is taken comprising the object and part of the free background; (c) even field is then adjusted and a second photograph is taken under the same conditions. (d) the photographs are quantitatively processed and the densities of selected areas of the object in even field and of the background in both even field and fringes are recorded by a microdensitometer; (e) the optical‐path differences are measured by comparing the densities in the object with those of the sinusoidal reference curve of the interference fringes. Experimental data are presented to validate the various steps of the procedure. The error of the method was found to vary from 2 to 9 p.c. when applied to sections of hyaline

ISSN:0368-3974    

DOI:10.1111/j.1365-2818.1965.tb02105.x

出版商:Blackwell Publishing Ltd    

年代:1965

数据来源: WILEY

摘要:

SYNOPSISAccurate and reproducible interference microscopy of unstained sections requires (a) the use of a shearing system, preferably with a half‐shade eye‐piece; (b) complete removal of embedding wax from the section; (c) complete replacement of one mounting medium by any successive medium; (d) accurate measurement of the refractive index (RI) of the mounting media at the temperature and wave‐length used for microscopy. The optical path through a specimen mounted in water is consistently lower than expected from measurements in non‐polar fluids—this is attributed to swelling of the tissues in water. Cellulose, glycogen and some mucins have a relatively low RI, and secretory granules and cytoplasmic chromidial substance a relatively high one. The highest RI observed was in calcified cartilage matrix. The “effective thickness” of tissue components, especially certain mucins, is often considerably less than the geometrical thickness of the section. This is attributed to the presence in the tissues of substantial spaces containing mounting medium.The relation of the RI and the effective thickness of tissue components in sections to their permeability to histological dyes is discussed. It is concluded that both the RI and the effective thickness may be of some value in predicting the ease with which dye particles of a given size can penetra

ISSN:0368-3974    

DOI:10.1111/j.1365-2818.1965.tb02106.x

出版商:Blackwell Publishing Ltd    

年代:1965

数据来源: WILEY

摘要:

SYNOPSISThe histology of the preputial skin and its appendages is described in the two African rhinoceros formsCeratotheriumandDiceros. Apocrine sweat glands occur in both. A feature of theCeratotheriumpenis is the presence of distinctive surface papillae which are the mouths of eccrine sweat glands whose secretory tubules are embedded in a mass of subepidermal lymphoid tissue, an arrangement hitherto unrecorded for any mammal.

ISSN:0368-3974    

DOI:10.1111/j.1365-2818.1965.tb02107.x

出版商:Blackwell Publishing Ltd    

年代:1965

数据来源: WILEY

摘要:

SYNOPSISThe need for microscopical test objects at the beginning of the 19th century is discussed. The first series of natural objects to serve as resolution tests was selected by Dr. C. R. Goringc. 1824. Later, diatoms were added as tests, but variations inherent in all natural objects made them unsuitable as universal standards. To meet this requirement, F. A. Nobert, a German optician, made artificial test objects by ruling series of lines on glass plates at definite distances apart. The first of these tests was produced in 1845, and comprised ten bands; the intended separation in the first band being 2·256 μ and in the tenth band 0·564 μ. A specimen of one of these ten‐band test‐plates, now in the possession of the Museum of the History of Science, Oxford, has been the subject of an optical and electron microscopical examination. The character of the rulings is described, and it is shown that the band spacing figures given by Nobert are substantially correct for this plate. The measured spacing in the first band is 2·172 μ and in the tent

ISSN:0368-3974    

DOI:10.1111/j.1365-2818.1965.tb02108.x

出版商:Blackwell Publishing Ltd    

年代:1965

数据来源: WILEY

ISSN:0368-3974    

DOI:10.1111/j.1365-2818.1965.tb02109.x

出版商:Blackwell Publishing Ltd    

年代:1965

数据来源: WILEY

ISSN:0368-3974    

DOI:10.1111/j.1365-2818.1965.tb02110.x

出版商:Blackwell Publishing Ltd    

年代:1965

数据来源: WILEY

ISSN:0368-3974    

DOI:10.1111/j.1365-2818.1965.tb02111.x

出版商:Blackwell Publishing Ltd    

年代:1965

数据来源: WILEY

摘要:

Book reviewed in this article:Die Grundzüge der Theorie des Mikroskops in elementarer Darstellung. 2nd edition. K. MichelModern Developments in Electron Microscopy. Edited by BenjaminM. Siegel.Arbeitsmethoden der makroskopischen und mikroskopischen Anatomie. HansAdamand GerhardCzihak.Science and the Skin. A. Jarrett.Cell Growth and Cell Division. Vol. 2 of the Symposia of the International Society for Cell Biology. Ed. R. J. C. HarrisBotanical Histochemistry, Principles and Practice. WilliamA. Jensen

ISSN:0368-3974    

DOI:10.1111/j.1365-2818.1965.tb02112.x

出版商:Blackwell Publishing Ltd    

年代:1965

数据来源: WILEY