Note 57 — Chapter I · (continued 2)

In order to detect the presence of starch-grains in plants, the tissue must be kept in alcohol exposed to light, until the whole of the chlorophyll is dissolved out; it must then be treated for several hours in a strong solution of potash. After neutralisation with acetic acid, the tissue may be treated with iodine, which colours it blue, or with coralline solution, which colours it pink.