Animals, machines, thunderstorms, and all forms of manual work, arouse the curiosity of children, whose thirst for knowledge puts the most intelligent adults to shame. This impulse grows weaker with advancing years, until at last what is unfamiliar inspires only disgust, with no desire for a closer acquaintance. This is the stage at which people announce that the country is going to the dogs, and that 'things are not what they were in my young days'.
Source: On Education, especially in early childhood, 1926, chap. 2 The Aims of Education