The main function of the lung is gas exchange, which can be assessed in several ways. A spirometer measures the flow and the volumes of the inspired and expired air. The thoracic and abdominal muscle strength plays an important role in pulmonary function and diffusing lung capacity. Formaldehyde is the simplest aldehyde that can be obtained from its cyclic trimer trioxane and the polymer paraformaldehyde. Aqueous solutions of formaldehyde are referred to as formalin. In 1867, the German chemist August Wilhelm Von Hofmann discovered formaldehyde. [1] Formaldehyde solutions are used as a fixative for microscopy and histology. Formaldehyde-based solutions are also used in embalming to disinfect and temporarily preserve human and animal remains. This is prepared by mixing the commercially available formalin solution with tap water in the proportion of 3:1. [2]