“The trout is protected by his colour,” said Uncle George. “Each trout is coloured like the bed of the stream he lives in, and the spots resemble grains of sand and tiny pebbles. The trout can change his colour, like the frog, as I will show you.” Uncle George took two trout out of the box and placed them in a glass dish. He placed the dish in a white saucer, and so arranged it that water was kept flowing into and out of it. Next day he took two more trout out of the box and placed them in the glass dish. It was then seen that the first two trout had grown quite light in colour. They were much paler than those taken out of the box, the inside of which was charred and black. One day Uncle George found two of the trout dead in the box. “I am afraid, boys,” he said, “that we cannot keep them confined any longer. Get a large pail full of water, and we will carry them to the brook.” “We must come here and fish next year, Frank,” said Tom, after the trout were transferred to the brook. “How long will it be before they become big trout, Uncle George?” “They are now about an inch long,” said Uncle George. “In a year they will be four inches long. In about three years, if they are not devoured by larger trout, they will weigh about a pound apiece.” “I think it is a shame to kill such pretty little creatures,” said Frank. “I quite agree with you, Frank,” said his uncle. Exercises on Lesson XIII. 1. Compare a newly-hatched trout with a seed (bean). How do they resemble, and how do they differ from one another? 2. The trout is protected by its colour markings. Make a list of any other animals you know that are “colour protected.” 3. If you put a fish (trout) into water which has been boiled and allowed to cool, it dies. What are your reasons for this? 4. Make notes, with sketches, of the development of a young trout from the time it is hatched until it requires food. XIV.—SILKWORMS. The silkworm eggs came in a very small box. They were sent by a friend of Uncle George’s who lived in the south of England. The eggs were stuck to pieces of paper in scattered groups. Some pieces of paper had only one or two eggs on them, others had as many as forty. They were small, round things, flattened on the top, and coloured light green. They reminded the boys of small mustard seeds, but they were not so round. In answer to Frank’s question as to why the eggs were laid in irregular groups, Uncle George answered: “When the silk-moth emerges from her pupa case, she lays her eggs anywhere on the floor of her cage. As the eggs are coated with a gluey material when newly laid, they stick firmly to the floor.