The microtomist's vade-mecum : a handbook of the methods of microscopic anatomy.

  • Lee, Arthur Bolles, 1849-1927.
Date:
1890
Catalogue details

Licence: Public Domain Mark

Credit: The microtomist's vade-mecum : a handbook of the methods of microscopic anatomy. Source: Wellcome Collection.

Provider: This material has been provided by The University of Leeds Library. The original may be consulted at The University of Leeds Library.

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    INTllODUOTOB?. is not necessary, may be dehydrated much quicker than this. Infusoria may be prepared in a few minutes.) The water having been thus completely removed, the alcohol is in its turn removed from the tissues, and its place taken by some anhydrous substance, generally an essential oil, which is iniscible with the material used for imbedding. This operation is known as Clearing. It is very important that the passage from the last alcohol to the clearing agent be made gradual. This is effected by placing the clearing medium under the alcohol. A sufficient quantity of alcohol is placed in a tube (a watch-glass will do, but tubes are generally better), and then with a pipette a sufficient quantity of clearing- medium is introduced at the bottom of the alcohol. Or you may first put the clearing medium into the tube, and then care- fully pour the alcohol on to the top of it. The two fluids mingle but slowly, The objects to be cleared being now quietly put into the supernatant alcohol, float at the surface of separation of the two fluids, the exchange of fluids takes place gradually, and the objects slowly sink down into the lower layer. When they have sunk to the bottom, the alcohol may be drawn off with a pipette, and the objects will be found to be completely penetrated by the clearing medium. (It may be noted here that this method of making the passage from one fluid to another applies to all cases in which objects have to be transferred from a lighter to a denser fluid—for instance, from alcohol, or from water, to glycerin. It is a more exact method than that of successive baths of mixture of alcohol and clearing agent.) The objects are now imbedded. They are removed from the clearing medium, and soaked until thoroughly penetrated in the imbedding medium. This is, for small objects, gene- rally parfiffin, liquefied by heat, and for large objects generally a solution of collodion or cello'idin. The imbedding medium containing the object is then made to solidify, as described in the chapter on imbedding processes, and sections are made with a microtome through the imbedding mass and the in- cluded objects. The sections are then mounted on a slide by one of the methods described in the chapter on Serial Section Methods, the imbedding material is removed from them (in the case of paraffin), they are stained in situ on the slide, dehydrated with alcohol, cleared, and mounted in balsam or