The spleen on its part is an immunologic blood filter. The spleen is of T cells, B cells, dendritic cells, natural killer cells, red blood cells and macrophages. The spleens function by capturing antigens from the blood passing through the spleen. The migratory macrophages together with the dendritic cells transport the foreign bodies to the spleen through the bloodstream. When the antigens get to the spleen and get into contact with the appropriate B or T cells, an immune response is initiated. The B cells once activated produces large amounts of antibody which kills the antigen as well as aged red blood cells. The spleen contains two types of T-cells which are helper T-cells and killer T-cells. The helper T-cells are responsible for systematising the attack while the killer T-cells destroys the infected cell since it has then been turned into a virus reproduction factory. The spleen is a secondary lymphoid organ since it contains both T and B cells and requires an antigen entry to stimulate the lymphoid cells (Turgeon, 2014). Since the tissue sections are in wax, they are placed in hot plates for 2 minutes till all the wax is melted, and no traces of wax found in the tissues. Within a two-minute interval, the tissues are placed in absolute alcohol, 90% alcohol and 70% alcohol. In order to stain the tissues, they are placed in Ehrlich’s Haematoxylin for 45 minutes. Since this is a regressive stain, over stained tissues will have the stain solution removed with a tissue paper and rinsed for 30 minutes with tap water. The tissues should appear bluish purple/dark blue.