Microoperations

MICROOPERATIONS, a general name for the most diverse operations and various experimental interventions in relation to small, very small, or microscopic objects, inasmuch as such operations and interventions, due to the insignificant size of the object or the special delicacy of the operations, cannot be conducted with the aid of ordinary experimental-surgical technique. Two main types of methods have outlined and developed comparatively long ago: on the one hand, the need to conduct experiments with objects visible only under a microscope (in bacteriology, for example, the necessity of isolating individual bacterial and yeast cells, in cytology the need for various interventions on the cytoplasm and nucleus of the cell) led to the creation of mechanical devices and apparatus (micromanipulators) by means of which the finest movements of special (most often glass) microinstruments can be carried out in the field of vision of the microscope, and to the development of a special methodology and technique—micrurgy (see). On the other hand, in experiments with objects that, although visible to the naked eye, are nevertheless sufficiently small (in developmental mechanics, for example, with eggs and embryos of early developmental stages, etc.), special instruments and a special technique were also found necessary for producing defects, ligation of the egg or embryo, embryonic transplantations, etc., but these operations are usually performed without the aid of a micromanipulator, simply by hand—"microsurgical technique" (in Spemann's terminology), which was already used by Roux, Born, and others and improved mainly by Spemann (see Developmental mechanics). If in some scientific fields one relies predominantly on one of them, in cytology, for example, on micrurgy, in developmental mechanics mainly on microsurgical technique, then in other fields methods of both the first type and the second find application, as well as various procedures of an intermediate character. In general, when working with larger objects, ordinary surgical instruments and usual procedures are used; for experiments with small objects, microinstruments and microsurgical methods; and with microscopically small objects, micrurgy. In microbiology, the isolation of individual bacterial and yeast cells is carried out both by means of methods that do not require special mechanical apparatus, a micromanipulator (Lindner's, Burri's methods, etc.), and with the help of a micromanipulator (see Micrurgy).