preparation

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preparation

1. something that is prepared, esp a medicinal formulation
2. esp in a boarding school
a. homework
b. the period reserved for this
3. Music
a. the anticipation of a dissonance so that the note producing it in one chord is first heard in the preceding chord as a consonance
b. a note so employed
4. the preliminary prayers at Mass or divine service

Preparation

 

the making of animal and plant specimens, including fossils, for study.

To prepare organisms for anatomical study, animals are dissected, and plants are dismembered. The separate organs or organ systems are placed in fixative fluids. For making total preparations, animal organs are set right and stained, the circulatory and respiratory systems are filled with slightly jelling mastics or plastics, and, sometimes, sections are made of certain organs. If necessary, the organs are attached to a supporting plate. For plant preparation, longitudinal, radial, tangential, transverse, and superficial sections of organs are made. Skeletons and chitinous and limestone carapaces, as well as the conducting systems of plants, are freed from the soft tissues by maceration or by boiling in special solutions, such as caustic alkalies. Mammals, birds, and reptiles can be stuffed (taxidermy), and, in some cases, the skin coverings are dried and mounted. A special form of plant preparation is the mounting of an herbarium.

Microscopic preparation of objects (entire microorganisms, separate organs, organ parts, tissues, cells, intracellular formations, molecular and submolecular structures) involves a very exact procedure. A wide range of fixatives, stains, and reagents for dehydration, clarification, impregnation, and differentiated separation of the objects under examination is used. The making of temporary or permanent specimens involves enclosing the specially treated object between a microscope slide and a cover glass (seeMICROTECHNIQUE).

The preparation of fossil objects involves freeing them from their enclosing rock. The cleaned objects are then impregnated with various fixing substances and covered with special lacquers. Imprints of organisms on an enclosing rock (usually including fragments of organs) are fixed and preserved on parts of the rock.

REFERENCES

Prokhorov, M. G. Instruktsiia dlia raskopok, preparovki i montirovki iskopaemykh pozvonochnykh, 2nd ed. Leningrad, 1931.
Komarov, V. L. Prakticheskii kurs anatomii rastenii, 8th ed. Moscow-Leningrad, 1941.
Romeis, B. Mikroskopicheskaia tekhnika. Moscow, 1954. (Translated from German.)
Dal’, K. K. Posobie dlia rabotnikov anatomo-zoologicheskikh muzeev i kafedr biologii. Dushanbe, 1965.
Zaslavskii, M. A. Izgotovlenie chuchel, muliazhei i modelei zhivotnykh. Obshchaia taksidermiia. Leningrad, 1968.
Kukhtina, Zh. M. Rukovodstvo k prakticheskim zaniatiiam po tsitologii. Moscow, 1971.

O. L. ROSSOLIMO

References in periodicals archive ?
In the late 1940s, direct touch preparations from skin lesions were prepared in North Africa and sent to Toronto, Canada, where they were examined successfully for smallpox virus for up to 4 months after collection (11).
One may chose to do core biopsies first, since cytologic preparations may be prepared by touch, crush, or scrape preparations of core biopsy tissue, thus saving the expense of an aspiration needle (Figs 2 and 3) Touch preparations have previously been shown to adequately evaluate needle placement.
Wright-stained touch preparations of the lymph node were performed.