The author has carried out experiments on the cataphorese of serum of rabbit by means of Vlcs's methods. The summary of experiments runs as follows: 1) Isoelectric point of normal serum lier between pH 5 and 6. 2) Isoelectric point of serum of pregnant rabbit moves towards acid side. 3) After injection of albumine medicament "Omnin", isoelectric point of serum moves towards acid side. 4) When body temperature is raised, by means of injection of several medicaments or putting animal in thermostat, isoelectric point of serum moves towards alkaline side. 5) After staying several hours in ice-room, isoelectric point of serum moves towards acid side.