Abstract: There is provided a method of an animal model experiment to observe cells implanted to an experimental small animal in which the position or spatial spread only of the implanted cells can be detected and observed with time progress and with sufficient accuracy while a plurality of kinds of the implanted cells can be distinguished from one another. The inventive method of in vivo detecting implanted cells implanted into the body of a small animal comprises steps of preparing cells used as the implanted cells into which a gene expressing a tag of a part of a peptide or a protein on a cell membrane is introduced; implanting the implanted cells to an arbitrary site of the small animal; and detecting the tags in the small animal. The tags may be detected by dosing the small animal with fluorescently labeled antibodies to the tags and imaging the fluorescence from the antibodies.

Abstract: In an in vivo microscopic observation method of the inside of the body of an experimental small animal using a stick type objective for an optical microscope, the determination of an observation site in the inside of the body of the animal and the checking of the position of the field of view of the objective can be done without significant increase of the burden of the tested animal. In the inventive method of the microscopic observation of a tissue or a cell in the inside of the body of a small animal, an endoscope is inserted through a first small hole opened in the epidermis site of the small animal; a second small hole piercing through the epidermis of the small animal is opened based on an image of the endoscope; and a thin diameter lens unit of the stick type objective is inserted in the second hole.

Abstract: The present invention provides an examination apparatus which includes a base; a stage on which a specimen is mounted, the stage being movable relative to the base; and a movable image acquisition apparatus for acquiring an image of the specimen, the movable image acquisition apparatus being fixed on the stage.