MORE than 100,000 pills were seized by police yesterday after a year-long observation led to four arrests in raids on two clinics in Kwun Tong. Two doctors and two nurses were given police bail for a combined total of $50,000 after being led away wearing black hoods. It is thought they may have been operating a racket whereby amphetamines were sold to addicts under the counter. The raids were a result of information gathered from questioning a number of arrested people in possession of the drug. About 20 police officers took part in the raids and seized a large number of records in addition to the drugs which are to be analysed. The four suspects were arrested under the Dangerous Drugs Ordinance and bailed to report back to Kwun Tong police in three weeks. Police acted on information leading them to believe the drugs were obtained without the proper procedure being followed. ''We were concerned that a lot of people were being arrested in the area with amphetamines in their possession,'' said detective superintendent Trevor Collins, the assistant divisional commander for crime in Kwun Tong. ''We were concerned about how they were being dispensed and decided to mount an operation.'' A series of controlled buys and periodic surveillance operation led to yesterday's raids. The doctors arrested were aged about 70 and 40 and the two nurses were in their 30s. Both clinics are owned by the same doctor. A police pharmacist and doctor accompanied the two teams. of 10 officers in yesterday's operations.