Omnibus of: HOSPITAL STATION (1962) + STAR SURGEON (1963) + MAJOR OPERATION (1971) - the first 3 books in White's "Sector General" series.

Hospital Station (1962) - a collection of related novelettes. Sector General is the home of many strange creatures, including humans. It is a vast, sectionalized hospital, set up in space to care for all kinds of extraterrestrials including those that "breathe" methane gas, or live under water or in some totally alien environment. Radiation-eating lifeforms with acute indigestion, casualties of a human-alien war, a spaceship colliding with the hospital and a fear-maddened creature playing havoc with the gravity grids are just some of the challenges junior intern Conway must tackle while he struggles to reconcile his pacifist ideals with the harsh reality of practising medicine in space.

Medic
Sector General
Trouble With Emily
Visitor at Large
Out-Patient

All of these first appeared in New Worlds, from 1957 to 1960.

Star Surgeon (1963) - a "fix-up" of "Resident Physician" and the serial "Field Hospital" from New Worlds 1961 & 1962. Sector General is a mercy station - a place where all kinds from all worlds are welcome. But for the first time, the hospital itself is threatened by aliens too different to understand its purpose and so powerful that they can cause utter havoc!

[This summary is extracted from P. Schuyler Miller's review from Analog September 1963...] "The puzzle comes when Conway is summoned to patch up a massive but sadly battered creature, considered a god by the races of its own galaxy and a criminal cannibal by the Monitor Corps of the Federation. Having solved this one with his usual combination of insight and hard work, Conway allows the critter - a dilettante do-gooder on a galactic scale - to lure him to a world which appears to be a museum of every possible disease and ailment to which Man is prone, or can become prone. And the solution to that one brings a prickly and beligerant empire down on the hospital, as the first step to a slugging war with the Federation. The siege of Sector General, and the medical, psychological and personal problems it generates, make up the last half of the book. With these stories, the English author [James White] has a tiger by the tail - and it's purring."

Major Operation - a collection of related novelettes (1971.) Sector General had hundreds of floors with every conceivable form of environment, pressure and gravity, designed to accomdate virtually any creature brought to it for observation or medical care. It was staffed with at least a hundred different species of doctors and nurses, and it was run by humans - probably the most generalized oxygen breathers in the galaxy. When a top-notch surgeon makes a series of fatal errors during an operation, Conway is assigned to find out what happened. He suspects that an outside alien presence is responsible, but is it a sentient virus, a disembodied intelligence, a mental contagion, or something totally beyond his experience? What he finds will take him to a planet literally crawling with life, and the most dangerous operating theatre in the galaxy...

Contents:
Invader
Vertigo
Blood Brother
Meatball
Major Operation

These first appeared in the British anthology series New Writings in SF (edited by John Carnell) - from 1966 to 1971.