___________ is the component of blood which is known as fighting cell.

Explanation

The water molecule associated with a crystalline substance is called .water of crystallisation..
Aim: To show crystalline salts contain water of crystallisation.
Materials Required : `CuSO_(4).5H_(2)O` (Blue vitriol), boiling tube, burner, cork, delivery tube, test tube, clamp stand.
Procedure:
1. Take 2 g of `CuSO_(4).5H_(2)O` in a boiling tube fitted in a clamp stand.
2. Observe its colour. Fit it with cork and delivery tube bent at two right angles which dips into a test tube.
3. Heat crystals in boiling tube.
4. Observe vapours being condensed in test tube.
5. Cool the crystals and add few drops of water into it.

Observation : Water vapours get condensed in a test tube and colour of blue crystals changes into white. On adding water to anhydrous copper sulphate it changes into blue again.
Chemical Reaction :
`underset("Blue vitriol")(CuSO_(4)5H_(2)O) overset("Heat")to CuSO_(4)+ underset("White")(5H_(2)O)`
Conclusion Crystalline substances have water of crystallisation which are lost on heating.