ABSTRACT
Immediate examination is done microscopically over living elements of parts that survive for a denite time. It can be done without any substance that modies its aspect or with a vital stain. The latter can be classied as intravital staining, when the dye is introduced in the animal while alive, or supravital staining, when the dye is added to structures that are preserved alive for a denite time, but outside the body of the animal. These kinds of examinations are done especially when observing protozoa, erythrocytes, leucocytes, and spermatozoids. The specimen is put between a slide and a glass cover with a drop of the liquid where the specimen comes from or another uid, such as plasma, serum, or isotonic solutions. In order to avoid dehydration, the glass cover must be sealed with petroleum jelly or parafn. To obtain long-life slides, it is necessary to apply denite techniques, which are described below in a practical way.
