These are the chemicals injected into the abdominal and thoracic cavities via the trocar. About two bottles of fluid are used per body. The chemical on the left has an index of 5 (5% formaldehyde) and the chemical on the right has an index of 22 (22% formaldehyde). Many embalmers prefer the lower index chemical because it preserves just as good or better than the higher index chemical, but doesn't have the strong fumes.