A formalin solution consisting of formaldehyde gas is dissolved in distilled water, and this solution is used to stabilize tissue samples in general as it protects tissues from the processes of putrefaction and disintegration caused by certain types of bacteria, and also keeps tissues closer than they are inside the living organism.
Formaldehyde is widely used in medical and industrial fields and as a preservative in the food industry. Formaldehyde is used as a reducing agent for silver ammonia in the manufacturing of mirrors. In medical fields, it is treated as a watery solution at different concentrations. It is used as a disinfectant at a concentration of 0.5% to kill bacteria, fungi and viruses, but its effect is slow. It is also used in sterilization and cleaning of surgical and diagnostic instruments and equipment in hospitals.