The waterworks were not built until a hundred years after the governor-general died. In 1872 another wise governor-general came to the islands, and learning of this money which had been left, he at once set to work to provide the city with a water supply. This was one of the best things that ever happened to Manila. In the tropics nothing is more important than pure water. There is a great deal of water in the body. In fact, three fourths of the body is made up of water. It is in the blood, in the muscles, and in the bones. There is even some water in the enamel of the teeth, which is the hardest substance in the whole body. The digestive juices, the saliva, and the different intestinal juices, all help to dissolve some part of the food which we take. To obtain this power to dissolve the food, they depend upon water. When a man is thirsty, it seems to him that his throat is dry. But dryness of the throat is only a sign by which the body makes known its need. Thirst is the cry of the fluids and tissues for water. It means that some part of the body is suffering for the precious fluid. If we look at a drop of water under a microscope, which magnifies it many times, we shall see in the water a great number of moving specks which are really little animals. The animals are so small that thousands of them can live in a single drop of water as happily as they could in a whole ocean of room. They are called germs. Some of them are wholesome: they help to keep the water bright and sparkling and sweet, and make it pleasant to the taste. But some of them are very harmful: they produce many kinds of disease, most of which cause death. It is because of these germs that people, particularly in tropical countries, have to be so careful about the water they drink. The purest water that we have is clean rain water. This is the vapor which rises from the earth and from the surface of the sea. It ascends into the air until it strikes a current of cold air, when it is turned into moisture and falls as rain. We can catch the rain water in cisterns or other vessels; and this water we may drink without boiling, if we are careful to keep the cisterns clean. The cistern, to be perfectly sweet, should be emptied and cleaned at least once every two weeks. [Illustration: THE WRONG PLACE FOR A WELL. ] In this country nearly all the drinking water comes from wells. Well water may be very good, but the chances are that it is full of impurities. The water from the wells is rain water which has soaked into the earth and has collected in the well. But the earth is always full of impurities. It is like a great sponge through which the water flows, and the water is pretty sure to take up some impurities as it sinks through the earth.