2. Immunological experiment 1: unknown bacteria+typhoid immune serum, unknown bacteria+dysentery immune serum, unknown bacteria+normal saline.
3. Complement hemolysis: 2% sheep red blood cells+hemolysin+normal saline do not hemolyze, 2% sheep red blood cells+complement+normal saline do not hemolyze, 2% sheep red blood cells+complement+hemolysin do not hemolyze, and 2% sheep red blood cells do not hemolyze.
4. Determination of serum immunoglobulin. Bidirectional agar diffusion test.
5. Enzyme-linked immunosorbent assay.