Page 1 : FIXATIVES - A fixative is a chemical used to kill and preserve the contents of the cell or parts of the, plant body in such a way they retain their original anatomical details even after their death. large number of, chemicals such as ethyl alcohol, formalin, acetic acid, chloroform, are used singly or in combinations as, fixatives for anatomical studies . Amongst these, formalin and formalin-aceto-alcohol (FAA) are most, commonly used in Anatomy., , 1, FORMALIN ACETIC ACID- FAA —, 1. 50% ethyl alcohol — 90 ml, 2. Glacial acetic acid — 5 ml, 3.Formalin 40% — 5 ml, , Preparation: Mix the reagents., The lower percentage of alcohol is more suitable for delicate materials, such as bryophytes. For hard, and woody materials, it is better to decrease the amount of acetic acid and to increase the amount of, formalin, , since formalin penetrates more slowly. The material may be left in FAA almost, indefinitely without any appreciable damage. The minimum time of fixation is 18 hours. Materials to, be sectioned are removed with forceps and washed in running water 1/2 to | hour and then handled, freely. This is a corrosive liquid, and if it comes in contact with the skin it should be washed-off, immediately., , 2. CORNOYS FLUID, Reagents:, 1 Absolute alcohol -30 ml, , 2.Chloroform -15 ml, 3.Glacial acetic acid — Sml, , Preparation: Mix the reagents; put in a well-fitted screw capped bottle to prevent evaporation., Use: Carnoy’s fluid is a rapid nuclear fixative used for fixing flowerbuds and root tips