Mark Kurlansky Quote

There is a white vein with a very small amount of liquid in it: … Men try to catch the murex alive because it discharges its juice when it dies. They obtain the juice from the larger purple-fish by removing the shell: they crush the smaller ones together with their shell, which is the only way to make them yield their juice.… The vein already mentioned is removed, and to this, salt has to be added in the proportion of about one pint for every 100 pounds. It should be left to dissolve for three days, since, the fresher the salt, the stronger it is. The mixture is then heated in a lead pot with about seven gallons of water to every fifty pounds and kept at a moderate temperature by a pipe connected to a furnace some distance away. This skims off the flesh which will have adhered to the veins, and after about nine days the cauldron is filtered and a washed fleece is dipped by way of a trial. Then the dyers heat the liquid until they feel confident of the result.—Gaius Plinius Secundus, Pliny the Elder, Historia naturalis, first century