PURPOSE: To simplify rinsing, drying and other operations for the titled distributor by forming it into a rotary body whereon concavities into which a serum can be poured separately are provided in plural places on the outer peripheral surface thereof.

CONSTITUTION: Flat surfaces 11, 12... are formed on the cylindrical main body 10, and a number of concavities 11a, 12a... are provided on each of these surfaces. Axes 19 are provided at both end surfaces 17 of the main body 10 respectively so that the body can be divided around the axes 19 by a dividing mechanism 20. Since the concavities as separate receivers are thus formed on a number of surfaces, the separate receibers for serum can be employed by dividing 20 the main body 10 by means of the axes 19. Because each of the concavities is very small, and therefore, the serum is prevented from dropping down by its surface tension.