On making lake. In the month of March, when plants and trees are drawing up sap from Mother Earth and gathering strength once more in growth, procure an augur, and pierce the branches of the ivy-plant here and there. And a liquid gum will flow out of them, and from this you can prepare a blood-red colour by cooking it. And this is called lake. So boil that colour with urine, and you will obtain a colour like blood, which is useful to scribes and to painters.