Chemists have been studying why people cry. They say the body
produces two kinds of tears. One kind cleans out the eye if it gets dirt in it.
But when people cry because of their feelings, these tears have poison chemicals
in them. The body is getting rid of chemicals produced by strong
feelings. In the United States men have heart diseases more
often than women do. Doctors say heart disease and some other diseases are
related to the pressures (压力) of living and working in a modern society. Perhaps
men suffer more from these diseases because they do not cry enough. And it is
possible that as more and more women work outside the home, they will also
suffer from more pressure. Then everyone will need to cry more. How many kinds of tears does the body produce