2.  This school should have two hours for the noon recess.

3.  This school should be in session from eight o’clock until one o’clock.

4.  All the pupils in this school should be seated in one room.

5.  The public library should be in the high school building.

6.  The football team should be excused early in order to practice.

7.  This school should have a greater number of public entertainments.

+72.  Explanation and Argument by Specific Instances.+—­Often we may make the meaning of a general proposition clear by citing specific instances.  If these instances are given for the purpose of explanation merely, the paragraph is exposition.  If, however, the aim is not merely to cause the reader to understand the proposition, but also to believe that it is true, we have argument.  In either case we have a paragraph developed by specific instances as discussed in Section 44.  Notice how in the following paragraph the author brings forward specific cases in order to prove the proposition:—­

Nearly everything that an animal does is the result of an inborn instinct acted upon by an outward stimulus.  The margin wherein intelligent choice plays a part is very small....  Instinct is undoubtedly often modified by intelligence, and intelligence is as often guided or prompted by instinct, but one need not hesitate long as to which side of the line any given act of man or beast belongs.  When the fox resorts to various tricks to outwit and delay the hound (if he ever consciously does so), he exercises a kind of intelligence—­the lower form of which we call cunning—­and he is prompted to this by an instinct of self-preservation.  When the birds set up a hue and cry about a hawk, or an owl, or boldly attack him, they show intelligence in its simpler form, the intelligence that recognizes its enemies, prompted again by the instinct of self-preservation.  When a hawk does not know a man on horseback from a horse, it shows a want of intelligence.  When a crow is kept away from a corn-field by a string stretched around it, the fact shows how masterful is its fear and how shallow its wit.  When a cat or a dog or a horse or a cow learns to open a gate or a door, it shows a degree of intelligence—­power to imitate, to profit by experience.  A machine could not learn to do it.  If the animal were to close the door or gate behind it, that would be another step in intelligence.  But its direct wants have no relation to the closing of the door, only to the opening of it.  To close the door involves an afterthought that an animal is not capable of.  A horse will hesitate to go upon thin ice or frail bridges.  This, no doubt, is an inherited instinct which has arisen in its ancestors from their fund of general experience with the world.  How much with them has depended upon a secure footing!  A pair of house-wrens had a nest in my well-curb; when the young were partly grown and heard any one enter the curb, they would set up a clamorous calling for food.  When I scratched against the sides of the curb beneath them like some animal trying to climb up, their voices instantly hushed; the instinct of fear promptly overcame the instinct of hunger!  Instinct is intelligence, but it is not the same as acquired individual intelligence; it is untaught.