Use this with KS4 work on blood, white cells, red cells, fighting off disease and how cuts heal. Offers an unusual launch for the standard work on the heart and blood pressure, but students should enjoy getting their teeth into it! For KS5 why not measure the iron content in Dracula’s victims? Make up some iron II salts (iron II ammonium sulphate solutions in dilute sulphuric acid, even some iron tablets work) and titrate with potassium VII Manganate. More dramatically mix iron III salts with potassium thiocyanate to get the deep blood red colour test for iron, and measure them with the colorimeter...or better dribble them down a gloved arm as you read the story...