professionals such as medical doctors would be quite unlikely to know just about anything. >> ricin is an antigen. a breakdown of red blood cells. in large enough doses, it can be fatal. when an antigen enters the body, the immune system's response is to produce antibodies to fight the invading organism. to find out whether rice and antibodies were in dr. farrar's's system doctors used a technique. in theory, any ricin antibodies in dr. farrar's blood wound bind to the ricin coached on the plate, which is exactly what happened. next, dr. richardson analyzed blood of goats that had been exposed to small amounts of ricin. it appeared that the goats and