摘要:

SYNOPSISTwo methods of testing microscope object‐glasses are described and classified as “Static” and “Kinematic.” The effects of residual aberrations are demonstrated and then a quantitative relation between the factors at the disposal of the microscopist and the residual aberration is given. A definition of “Sensitivity” follows with numerical values for certain lenses. The effects of variations of cover‐glass thickness and refractive index and variation of immersion‐oil refractive index are discussed with the aid of the conce

ISSN:0368-3974    

DOI:10.1111/j.1365-2818.1952.tb00989.x

出版商:Blackwell Publishing Ltd    

年代:1952

数据来源: WILEY

摘要:

SYNOPSIS.It is shown that by making certain simplifying assumptions quantitative results can be obtained from a geometrical vector representation of phase contrast. Formulae for the intensity and contrast in the general case, and in a number of special cases, including central dark‐ground illumination, are derived, and are shown to be identical with those obtained by more elaborate mathematical procedures. The present paper is mainly devoted to a detailed discussion of some aspects of positive phase contrast. The appearances of (a) pure phase objects, and (b) mixed phase and amplitude objects are considered for (1) a non‐absorbing 90° phase plate, (2) 90° phase plates of any absorption, and (3) non‐absorbing phase plates in which the phase of the direct light is advanced by any angle Ψ. The bearing of some of the results on the selection of the optimum type of phase plate for a given purpose is d

ISSN:0368-3974    

DOI:10.1111/j.1365-2818.1952.tb00990.x

出版商:Blackwell Publishing Ltd    

年代:1952

数据来源: WILEY

摘要:

SYNOPSIS.The requirements for microscope eyepieces for visual use are considered and the possibilities of achieving them are discussed in relation to the conditions under which the system is required to work. Eyepieces of various types for both visual and photomicrographic purposes are described and illustrated.

ISSN:0368-3974    

DOI:10.1111/j.1365-2818.1952.tb00991.x

出版商:Blackwell Publishing Ltd    

年代:1952

数据来源: WILEY

摘要:

SYNOPSIS.The structure of the hypodermal “pillar”‐cell layer of the testa has been examined in 15 leguminous species and, for each, the diagnostic characters of the testa, as seen in radial section, have been tabulated and figured.In the following species the “pillar” cells formed a single hypodermal layer:Lotus corniculatus, L. ornithopodioides, L. requienii, L. uliginosus, Dorycnium rectum, Ononis arvensis, Psoralea corylifolia, Ornithopus sativus, andMucuna urens.No evidence of an intermediate layer of parenchymatous cells lying between the epidermis and the “pillar” cells has been found in these species.The “pillar” cells form a single hypodermal layer inVoandzeia subterraneaandLotus tetragonolobus.InPhysostigma venenosum1–3 layers of thick‐walled transition cells lie between the single layer of “pillar” cells and the inner layers of thin‐walled parenchyma. InTamarindus indicaa similar arrangement is found but there are many layers of transition cells which are either cubical or stellate in shape or are much compressed.Several layers of “pillar” cells form the hypodermal zone in the testa ofAnagyris fœtidaand ofCopaifera salikounda, the cells of the true hypodermal layer being of somewhat greater radial length than are the remaining cells of this zone. In both species the cells below the hypodermal zone are thick‐walled

ISSN:0368-3974    

DOI:10.1111/j.1365-2818.1952.tb00992.x

出版商:Blackwell Publishing Ltd    

年代:1952

数据来源: WILEY

摘要:

A new technique is described for the preparation of biological specimens for electron microscope study, a de Fonbrune micromanipulator and an inverted microscope being used. The microdissection is made directly on the collodion film supported by a thin glass slide (cover‐slip) and afterwards the specimen is mounted on a grid. The method is illustrated with electron micrographs of nuclear and cell membranes, and its advantages are discusse

ISSN:0368-3974    

DOI:10.1111/j.1365-2818.1952.tb00993.x

出版商:Blackwell Publishing Ltd    

年代:1952

数据来源: WILEY

ISSN:0368-3974    

DOI:10.1111/j.1365-2818.1952.tb00994.x

出版商:Blackwell Publishing Ltd    

年代:1952

数据来源: WILEY

摘要:

A technique for the galvanotropic separation of indigenous ciliate protozoa from the rumen contents of sheep is presented. A fractionation of these isolated protozoa into three populations—isotrichs, large oligotrichs, small oligotrichs—is described and illustrated. Some applications of these findings in rumen microbiology are enumera

ISSN:0368-3974    

DOI:10.1111/j.1365-2818.1952.tb00995.x

出版商:Blackwell Publishing Ltd    

年代:1952

数据来源: WILEY

ISSN:0368-3974    

DOI:10.1111/j.1365-2818.1952.tb00996.x

出版商:Blackwell Publishing Ltd    

年代:1952

数据来源: WILEY

ISSN:0368-3974    

DOI:10.1111/j.1365-2818.1952.tb00997.x

出版商:Blackwell Publishing Ltd    

年代:1952

数据来源: WILEY

ISSN:0368-3974    

DOI:10.1111/j.1365-2818.1952.tb00998.x

出版商:Blackwell Publishing Ltd    

年代:1952

数据来源: WILEY