"I can think of a few microorganisms, possibly the tubercle bacillus, the syphilis spirochete, the malarial parasite, and a few others, that have a selective advantage in their ability to infect human beings, but there is nothing to be gained, in an evolutionary sense, by the capacity to cause illness or death. Pathogenicity may be something of a disadvantage for most microbes, carrying lethal risks far more frightening to them than to us. The man who catches a meningococcus is in considerably less danger for his life, even without chemotherapy, than meningococci with the bad luck to catch a man."

“The great secret, known to internists and learned early in marriage by internist’s wives, but still hidden from the general public, is that most things get better by themselves. Most things, in fact, are better by morning. Obviously, it is a great time-saver and money-saver for the physician’s family that anxiety about disease is not handled as though it were the disease itself; there is perhaps greater willingness to accept anxiety as a natural, often transient, phenomenon. And certainly there is much less ambition to deploy the full technology of medicine as a corrective for the human condition.”

“Maybe there is a single spot, just one, where living organisms are holed up. Maybe so, but if so this would be the strangest thing of all, absolutely incomprehensible. For we are not familiar with this kind of living. We do not have solitary, isolated creatures. It is beyond our imagination to conceive of a single form of life that exists alone and independent, unattached to other forms.”

“Maybe altruism is our most primitive attribute out of reach, beyond our control. Or perhaps it is immediately at hand, waiting to be released, disguised now, in our kind of civilization as affection or friendship or attachment. I can’t see why it should be unreasonable for all human beings to have strands of DNA coiled up in chromosomes, coding out instincts for usefulness and helpfulness. Usefulness may turn out to be the hardest test of fitness for survival, more important than aggression, more effective, in the long run, than grabbiness.”

“We are endowed with genes which code out our reaction to beavers and otters, maybe our reaction to each other as well. We are stamped with stereotyped, unalterable patterns of response, ready to be released. And the behavior released in us, by such confrontations, is, essentially, a surprised affection. It is compulsory behavior and we can avoid it only by straining with the full power of our conscious minds, making up conscious excuses all the way. Left to ourselves, mechanistic and autonomic, we hanker for friends.”

“The cloning of humans is on most of the lists of things to worry about from Science, along with behavior control, genetic engineering, transplanted heads, computer poetry and the unrestrained growth of plastic flowers.”

“Everything here is alive thanks to the living of everything else.”