THE FIRST SECTION OF THIS PAPER GIVES AN OVERVIEW OF ATTEMPTS BY FORENSIC SCIENTISTS TO DEVELOP A RELIABLE METHOD TO IDENTIFY SEMINAL FLUID IN THE ABSENCE OF SPERMATOZOA. IT BEGINS WITH THE DEVELOPMENT OF THE FLORENCE TEST IN 1896, CONTINUES THROUGH THE VARIOUS MICROCHEMICAL TESTS OF THE 1940'S, AND REVIEWS TESTS BASED ON THE ACID PHOSPHATASE (AP) CONTENT OF SEMINAL FLUID DEVELOPED IN THE 1950'S. OF THESE, THE MODIFIED AP TEST DEVELOPED BY SCHIFF IS CONSIDERED SIMPLE AND RELIABLE ENOUGH FOR FORENSIC USE. THIS TEST USES VAGINAL SWABS PREPARED WITH AN ACIDIFIED, SATURATE SOLUTION OF SODIUM ALPHA-NAPHTHYL PHOSPHATE. THESE ARE STORED IN A REFRIGERATOR, AND HAVE PROVED SEVICEABLE EVEN 6 YEARS AFTER PREPARATION. A BUFFER OF CITRIC ACID MONOHYDRATE SOLUTION AND A COLOR DEVELOPER, BRENTAMINE FAST BLUE B, ARE THE OTHER ITEMS NEEDED. THE PROCEDURES IS DESCRIBED. VAGINAL ASPIRATES WERE COLLECTED FROM 10 ALLEGED RAPE VICTIMS 1 HOUR TO 4 DAYS AFTER THE ATTACK. A TABLE PRESENTS THE DATA FROM THESE 61 WHITE AND 39 BLACK FEMALES. IN 51 PERCENT OF THE CASES BOTH AP AND SPERMATOZOA WERE FOUND. GIVEN THE TIME FACTOR AND THE VARIOUS CASES IN WHICH PENETRATION DID NOT OCCUR OR IN WHICH THERE WERE OTHER EXPLANATIONS FOR THE ABSENCE OF SPERMATOZOA, THERE APPEARS TO BE AN ABSOLUTE PARALLEL BETWEEN THE PRESENCE OF AP AND THE PRESENCE OF SPERMATOZOA. BECASE THE AP TEST IS SIMPLE AND CAN BE PERFORMED IN A FEW MINUTES, IT IS RECOMMENDED FOR RAPE CASES. FACTORS WHICH AFFECT AP TEST RESULTS ARE DISCUSSED. REFERENCES ARE PROVIDED. (GLR)