THE FIRST BORDER PATROL WAS A SMALL GROUP OF MOUNTED INSPECTORS ESTABLISHED IN 1904. IN THE EARLY DAYS OF THE PATROL, THE FORCE'S MAIN EFFORTS WERE CONCENTRATED ON LIQUER SMUGGLERS AND GUN RUNNERS. THE BASIC OPERATION OF THE BORDER PATROL TODAY IS RIVER OR LINE WATCH, WHERE ILLEGAL IMMIGRANTS OR SMUGGLERS ARE DETAINED. IN ADDITION TO SUCH MODERN EQUIPMENT AS RADIO COMMUNICATIONS, ELECTRONIC SENSORS, AND AIRPLANE SURVEILLANCE, THE OFFICERS MAKE USE OF THE OLD TECHNIQUE OF SIGN CUTTING, DEFINED AS THE OBJECTION OF MARKS, TRACKS, AND PHYSICAL EVIDENCE LEFT BY THE MOVEMENTS OF PERSONS OR VEHICLES. SOME STATISTICS ON NUMBERS OF ALIENS APPREHENDED ARE REPORTED. ALSO, A BRIEF REVIEW OF METHODS OF ILLEGAL ENTRY USED BY ALIENS IS PROVIDED. FORMAL BORDER PATROL TRAINING IN IMMIGRATION AND NATIONALITY LAWS, SPANISH, DUTIES AND AUTHORITY TO ACT, FIRST AID, PHYSICAL TRAINING, SELF DEFENSE, EVIDENCE, CRIMINAL LAW, AND FIREARMS IS PROVIDED IN A FULL TIME 16 WEEK TRAINING COURSE.