ISSN:0368-3974    

DOI:10.1111/j.1365-2818.1955.tb00411.x

出版商:Blackwell Publishing Ltd    

年代:1955

数据来源: WILEY

摘要:

SYNOPSISPancreatic secretion has been studied in cells which have not been stimulated by artificial means. Under natural conditions it has been shown that there exists asecretion cyclewhich consists of three main phases: 1.Recoveryphase, during which zymogen synthesis is maximal; 2.Restingphase during which zymogen synthesis is minimal; and 3.Dischargephase, in which zymogen is lost from the cells. Zymogen synthesis is brought about by certain lipoidal prozymogen bodies which originate from mitochondria in the form of small granules. These pass towards the Golgi apparatus, probably receive some contribution from it, and become vacuolated. Bach vacuolated prozymogen body consists of an outer lipoidal coat enveloping an immature zymogen granule. Eventually the lipoidal coat is shed and a mature zymogen granule is produced. The loss of zymogen from the cells is brought about in a similar way. Amongst the zymogen granules there appear small secretion bodies which gradually increase in size. Each secretion body consists of an outer lipoidal coat and an inner substance which is probably formed by the liquifaction and absorption of zymogen granules. Eventually the secretion bodies are extruded into either intercellular secretion canaliculi or lumina along which they may pass intact into the duct system. With the possibility of rare exceptions, it is secretion bodies which are actually extruded ordischargedfrom the cells and not the zymogen granules. Finally it appears that both the synthesis of zymogen granules and their absorption is brought about by the activity of an intracellular lipoidal cycle.

ISSN:0368-3974    

DOI:10.1111/j.1365-2818.1955.tb00412.x

出版商:Blackwell Publishing Ltd    

年代:1955

数据来源: WILEY

摘要:

SYNOPSISThe Pointolite is a good source of intense illumination for microscopy, provided that a sufficiently powerful bull's‐eye is used to ensure that the image of the tungsten ball covers the aperture of the substage condenser. The bull's‐eye should be of as short a focal length as the size of the glass bulb will allow. A new lamp to carry the Pointolite is described. Careful instructions are given for centring, focusing, and aiming the li

ISSN:0368-3974    

DOI:10.1111/j.1365-2818.1955.tb00413.x

出版商:Blackwell Publishing Ltd    

年代:1955

数据来源: WILEY

摘要:

SYNOPSISA technique is described for transferring cells prepared on slides coated with Formvar to specimen supporting grids of the electron microscope.

ISSN:0368-3974    

DOI:10.1111/j.1365-2818.1955.tb00414.x

出版商:Blackwell Publishing Ltd    

年代:1955

数据来源: WILEY

摘要:

SYNOPSISThe histological changes in the dermis of Kerry Hill lambs throughout a year have been investigated. The main change observed was in the sweat glands which were largest in the warmer months: the mechanism by which they appear and disappear is indicated. Fat varied irregularly. Elastin and reticulin were not found to vary according to age or season.

ISSN:0368-3974    

DOI:10.1111/j.1365-2818.1955.tb00415.x

出版商:Blackwell Publishing Ltd    

年代:1955

数据来源: WILEY

摘要:

SYNOPSISFurther successful techniques for embedding botanical materials (leaf and stem ofRubus idœeus) in various polyethylene glycol media are outlined. A method of incorporating celloidin into polyethylene glycol media and polyethylene glycol monostearate (“Nonex 63B”) is described. The utility of the various embedding media is discussed. Details of permanent mounting of ribbons of serial sections in several polyvinyl alcohol mountants are given.It is concluded that the methods are especially suitable for the rapid production of large numbers of permanently mounted thin serial sections, the cells of which are virtually undistorted. Such mounts therefore lend themselves particularly to reproduction by means of high‐power camera‐lucida or projection drawings. The utility of the mounts is enhanced by the incorporation of simple cellulosic stains into the polyvinyl alcohol mountants.The use of celloidin in conjunction with these dehydrating and embedding reagents is concluded to be of limited application only, in this pres

ISSN:0368-3974    

DOI:10.1111/j.1365-2818.1955.tb00416.x

出版商:Blackwell Publishing Ltd    

年代:1955

数据来源: WILEY

摘要:

SYNOPSISThe detailed anatomy of the roots ofSymphytum officinaleL. is described and figured. The diagnostic microscopical characters which may be used to identify these roots when present in the crushed or powdered condition are: large cork cells, irregular in outline, up to 250μ in tangential width; abundant parenchyma of phelloderm, phloem, and xylem, including medullary rays, of sub‐rectangular cells arranged in radial files and containing mucilage, also starch granules both simple and 2‐ to 4‐ compound; xylem vessels solitary or in groups of 2 or 3 (rarely more than 3), with many rows of bordered pits; corrected vessel number per mm.2is 40‐56‐85; absence of calcium oxalate crystals, laticiferous tissue and lignified elements other than vessels. The diagnostic features which enable the roots of dandelion and of chicory to be distinguished from that of comfrey when in admixture are tabulated. A method for the quantitative examination of dandelion coffee is described. Nine commercial samples of dandelion coffee were found to contain between 50 p.c. and 80 p.c. of roasted dandelion root: each sample contained roasted comfrey root and some also contained roasted chicory root. Such material was not considered to be of the nature, substance, and quality of dandelion coffee, which earlier workers have regarded as composed of pure roasted dand

ISSN:0368-3974    

DOI:10.1111/j.1365-2818.1955.tb00417.x

出版商:Blackwell Publishing Ltd    

年代:1955

数据来源: WILEY

摘要:

SYNOPSISThe paper describes an apparatus for rotating a small crystal about a single axis while it is immersed in a liquid of known refractive index, for use with the polarizing microscope. An auxiliary apparatus for mounting the crystal in a desired orientation with reference to the axis of rotation is also described.

ISSN:0368-3974    

DOI:10.1111/j.1365-2818.1955.tb00418.x

出版商:Blackwell Publishing Ltd    

年代:1955

数据来源: WILEY

ISSN:0368-3974    

DOI:10.1111/j.1365-2818.1955.tb00419.x

出版商:Blackwell Publishing Ltd    

年代:1955

数据来源: WILEY

摘要:

Book reviewed in this article:De Hollandsche Maatschappij Der Wetenschappen (1752–1952).—Dr. J. A. Bierens de HaanDas Phasenkontrastverfahren in der Medizin. (Phase‐contrast microscopy applied to Medicine.) —Hans‐Georg Hansen, Alexander Rominger, and Kurt Michel.Radiations and Living Cells.—F. G. Spear.Entomological Photography in Practice.

ISSN:0368-3974    

DOI:10.1111/j.1365-2818.1955.tb00420.x

出版商:Blackwell Publishing Ltd    

年代:1955

数据来源: WILEY