The need for a surgical operation，especially an emergency operation，almost always comes as a severe shock to the patient and his family．Despite modern advances，most people still unreasonably fear hospitals and anesthetics （麻醉药）．Patients do not often believe they really need surgery---cutting into a part of the body as opposed to treatment with drugs．

In the early years of this century there was little specialization in surgery．A good surgeon was capable of performing almost every operation that had been devised up to that time．Today the situation is different．Operations are now being carried out that were not even dreamed of fifty years ago．The heart can be safely opened and its valves （阀门；心脏或血管的瓣膜） repaired．Clogged blood vessels can be cleaned out，and broken ones mended or replaced．A lung，the whole stomach，or even part of the brain can be removed and still permit the patient to live a comfortable and satisfactory life．However，not every surgeon wants to，or is qualified to carry out every type of modern operation．

The scope（范围，广度，机会） of surgery has increased remarkably in this century．Its safety has increased too．Deaths from most operations are about 20% of what they were in 1910and surgery has been extended in many directions，for example to certain types of birth defects （缺陷） in newborn babies，and，at the other end of the scale，to life-saving operations for the octogenarian （八旬老人）．The hospital stay after surgery has been shortened to as little as a week for most major operations．Most patients are out of bed on the day after an operation and may be back at work in two or three weeks．

Many developments in modern surgery are almost unbelievable．They include the replacement of damaged blood vessels with simulated ones made of plastic； the replacement of heart valves with plastic substitutes； the transplanting of tissues such as the lens of the eye； the invention of the artificial kidney to clean the blood of poisons at regular intervals an