Phineas Gage, a 25-year-old railroad foreman, was setting dynamite charges on a Vermont construction site one day in 1848 when an explosion drove an inch-thick, 3 1/2-foot-long spike through his left cheek and out the front of his skull.

The energetic Gage miraculously survived the injury but underwent a curious change of personality, becoming lazy, irreverent and docile. The spike, which had severed Gage's frontal lobe from the rest of his brain, had given him, albeit accidentally, the first recorded lobotomy.

Some 90 years later, lobotomists such as Walter Freeman and James Watts at George Washington University Medical School sought to duplicate in a more discriminate and less gory form what had happened to Gage. Although there eventually emerged almost as many psychosurgical techniques as there were surgeons, the standard lobotomy and its transorbital variation perfected by Watts and Freeman were perhaps the most popular during the peak lobotomy years of 1936 to 1960.

In the standard operation, Freeman and Watts entered the skull by drilling small burr holes near each temple. They then angled a blunt surgical knife about three inches into the front lobe and swung it gently up and down to sever the white nerve passageways between the lobe and the thalamus, one of the brain's centers.

The operation often took more than an hour because the surgeons could not see through the drill holes and so worked "blind." The doctors preferred to use only a local anesthetic because a marked change in a patient's demeanor on the operating table was one way for them to tell how much they had cut.

Finding the standard lobotomy too slow and complex for mass use, Freeman eventually perfected the transorbital method by which the skull was entered with an icepick-style surgical knife inserted two to three inches into the brain through the eye cavity. Again the knife was gently manipulated through the front lobe's four quardrants to sever its nerve passageways.

Neither operation was acceptable to many surgeons, who feared internal hemorrhaging could not be stopped with "blind cut" procedures. Several developed "operations by sawing out a large chunk of skull above the forehead. Some cut all four frontal lobe quardrants, while others severed only selected nerve tissue. Still others perfected ways of cutting other parts of the brain.

The operations varied so greatly that lobotomy advocate Harry C. Solomon, writing for the Veterans Administration in 1948, complained, "There is little uniformity among different operators as to the total amount of white substance cut or of gray matter destroyed. It is probably that, similarly, there is no uniformity as to the exact site at which the surgical destruction is imposed."