The Microscope: Its History, Construction, and Application, Being a Familiar Introduction to the Use of the Instrument, and the Study of Microscopical Science

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G. Routledge & Sons, 1911 - 704 pages
 

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Page 14 - When a ray of light passes from one medium to another, it is refracted so that the ratio of the sine of the angle of incidence to the sine of the angle of refraction is equal to the ratio of the velocities in the two media.
Page 248 - ... focus the slit. A side slit capable of adjustment admits when required a second beam of light from any object whose spectrum it is desired to compare with that of the object placed on the stage of the microscope. This second beam of light strikes against a very small prism, suitably placed inside the apparatus, and is reflected up through the compound prism, forming a spectrum in the same field with that obtained from the object on the stage. a is a brass tube carrying the compound direct-vision...
Page 249 - To use this instrument, insert g like an eyepiece in the microscope tube, taking care that the slit at the top of the eyepiece is in the same direction as the slit below the prism. Screw on to the microscope the object-glass required, and place the object whose spectrum is to be viewed on the stage. Illuminate with stage mirror if transparent, with mirror and Lieberkiihn and darken well if opaque, or by side-reflector bull's-eye, &c.
Page 369 - The micro-organisms mutt be isolated from the blood, lymph, or tissues, and cultivated in suitable media, ie, outside the animal body. These pure cultivations must be carried on through successive generations of the organism. " 3. A pure cultivation thus obtained must, when introduced into the body of...
Page 249 - Having focussed the object, replace a, and gradually close the slit till a good spectrum is obtained. The spectrum will be much improved by throwing the object a little out of focus. Every part of the spectrum differs a little from adjacent parts in refrangibility, and delicate bands or lines can only be brought out by accurately focussing their own parts of the spectrum.
Page 424 - ... put on the appearance of the old portions. As they increase in size the original segments are pushed away from each other, and at length an entire separation takes place, each old segment taking with it a new segment to supply the place of the old one. This process is seen going on in fig. 5. This process is repeated again and again, so that the older segments are united successively, as it were, with many generations.
Page xi - Prayer written within this minute compass. The microscope detects the invisible ingredients which adulterate our food, our drink, and our medicines. It tells the murderer that the blood which stains him is that of his brother, and not of the other life which he pretends to have taken ; and, as a witness against the criminal, it, on one occasion, appealed to the very sand on which he trod at midnight.
Page 462 - ... that are alike in age, some of the vessels retain their contents while others do not. Nay, we even find that the younger vessels are more pervious than the older ones, if round the younger ones there is a formation of wood. Thus, then, is confirmed the inference before drawn, that in ordinary stems the staining of the wood by an ascending coloured liquid is due, not to the passage of the coloured liquid up the substance of the wood, but to the permeability of its ducts and such of its pitted...
Page 554 - If, at the same time, it is confined within a narrow cell, or space, it grows only to such a size as will enable it to move about freely; thus it is made to adapt itself to the necessities of a restricted state of existence. Some young animals in a narrow glass-cell, at the end of six months...
Page 45 - ... that the function of the condenser in microscopic practice is to cause the object to behave, at any rate in some degree, as if it were self-luminous, and thus to obviate the sharply-marked interference-bands which arise when permanent and definite phase-relations are permitted to exist between the radiations which issue from various points of the object.

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