A Contribution to the Bio-Chemistry of Haemolysis:—(a) Changes in Solubility of the Lipoids in presence of one another, and of certain Unsaturated Organic Substances. (b) The Balancing Action of Certain Pairs of Haemolysers in Preventing Haemolysis. (c) The Protective Action of Serum Proteins Against Haemolysers. (d) The Effects of Oxydising and Reducing Agents Upon Haemolysis