Reading is a pleasure of the mind, which means that it is a little like a sport: your eagerness and knowledge and quickness make you a good reader. Reading is fun, not because the writer is telling you something, but because it makes your mind work.
Your own imagination works along with the author's or even goes beyond his. Your experience, compared with his, brings you to the same or different conclusions, and your ideas develop as you understand his.
Every book stands by itself, like a one-family house, but books in a library are like houses in a city.
Although they are separate, together they all add up to something; they are connected with each other and with other cities.
The same ideas, or related ones, turn up in different places; the human problems that repeat themselves in life repeat themselves in literature, but with different solutions according to different writings at different times.
Reading can only be fun if you expect it to be. If you concentrate on books somebody tells you "ought" to read, you probably won't have fun.
But if you put down a book you don't like and try another till you find one that means something to you, and then relax with it, you will almost certainly have a good time--and if you become as a result of reading, better, wiser, kinder, or more gentle, you won't have suffered during the process.
【Cells and Temperature】
Cells cannot remain alive outside certain limits of temperature and much narrower limits mark the boundaries of effective functioning.
Enzyme systems of mammals and birds are most efficient only within a narrow range around 37C;a departure of a few degrees from this value seriously impairs their functioning.
Even though cells can survive wider fluctuations the integrated actions of bodily systems are impaired. Other animals have a wider tolerance for changes of bodily temperature.
For centuries it has been recognized that mammals and birds differ from other animals in the way they regulate body temperature.
Ways of characterizing the difference have become more accurate and meaningful over time, but popular terminology still reflects the old division into “warm-blooded” and “cold-blooded” species; warm-blooded included mammals and birds whereas all other creatures were considered cold-blooded.
As more species were studied, it became evident that this classification was inadequate.
A fence lizard or a desert iguana—each cold-blooded----usually has a body temperature only a degree or two below that of humans and so is not cold.
Therefore the next distinction was made between animals that maintain a constant body temperature, called homeotherms, and those whose body temperature varies with their environments, called poikilotherms.
But this classification also proved inadequate, because among mammals there are many that vary their body temperatures during hibernation.
Furthermore, many invertebrates that live in the depths of the ocean never experience change in the depths of the ocean never experience change in the chill of the deep water, and their body temperatures remain constant.