In this way 25,000,000 mussels were carried last year to streams where mussels are known to thrive. If these mussel-bearing fish can be obtained by farmers having private fish ponds, the ponds can be drained each year and the mussels gathered, thus adding considerably to the owner's income, and also keeping up the pearl button industry, in addition to the food supply which he gains from the fish. Enough has been said to show clearly how desirable and how possible it is to conserve and increase our fish supplies. With the cooeperation of all who waste the fish at present, and those who might aid in stocking the streams, we could add greatly to the food supply of the nation at a less cost than in any other way. REFERENCES Grazing Lands. Report National Conservation Commission. Grazing on the Public Lands. (Jastro.) Report Governor's Conference. The Grazing Lands and Public Forests of Arizona. (Heard.) Report Governor's Conference. Grazing Problems in the Southwest and How to Meet Them. Bulletin, Dept. of Agriculture, 5c. Reports of the Bureau of Animal Industry. Dept. of Agriculture. Distribution of Fish and Fish Eggs. Dept. Commerce and Labor.[B] [Footnote B: All Bureau and Commission reports are free.] Reports of the Commission of Fisheries. National Fisheries Congress. CHAPTER X INSECTS If we look at a watch, we see that one wheel can not move until the one next in order to it moves, and that, in turn, must be set in motion by another wheel. In the same way nature adjusts itself in its various parts. Before man enters a region, the balance is perfect. Plants crowd each other out of the way, the weaker giving place to the stronger; then insects come to destroy them. These insects are destroyed by birds, small mammals or other insects. The birds are killed by animals and other birds, which in turn are the food of larger animals. And so through all nature runs this law of balance; nothing increases in too great a proportion. But when man comes, he thinks only of his own needs and wishes and begins at once to upset the delicate balance. Year after year, he plants large fields of a single crop, and, calling other plants weeds, because they hinder the growth of his grain, he drives them out entirely. The insects that feed on these plants, finding no food, soon disappear, while the ones which feed on the farmers' crops, finding food so plentiful, are able to increase in great numbers. They increase all the more rapidly because man, not knowing or not caring to know who his real helpers are, has killed and driven away the birds that would feed on them. In order to readjust matters, he must learn how to destroy the insects, or he can not have crops. Both the plant enemies, the weeds, and the insects are always trying to bring about nature's balance again by driving out the over-abundant field crop, so he must constantly fight them in order to secure his harvest.