"What is it--the bachelor's friend--or every man his own tailor? Fasten a button on with a pair of gas-pliers so that you have to take the trousers apart when you want to get it off?" "Something like that, yes," laughed Dunk, "only simpler. Look here!" He pulled up the back of his vest and showed Andy where a suspender button was missing. In its place Dunk had taken a horseshoe nail, pushed it through a fold of the trousers, and had caught the loop of the braces over the nail. "Isn't that some classy little contrivance?" he asked, proudly. "Not that I take any credit to myself, though. Far be it! I got the idea out of the comic supplement. But it works all right, and the beauty of it is that you can use the nail over and over again. It is practically indestructible. "So you see if you are wearing the nail all day, to lectures and so on, and if you have to put on your glad rags at night to go see a girl, or anything like that, and find a button missing, you simply remove the nail from your day-pants and attach it to your night ones. Same suspenders--same nail. It beats the bachelor's friend all to pieces." "I should imagine so," laughed Andy. "I'll have to lay in a stock of those nails myself. The way tailors sew buttons on trousers nowadays is a scandal. They don't last a week." "There's one trouble, though," went on Dunk, and he carefully examined his simple suspender attachment as if in fear of losing it. "With the increasing number of autos, and the decrease in horses, there is bound to be a corresponding decrease in horseshoe nails. That's a principle of economics which I am going to bring to the attention of Professor Shandy. He likes to lecture on such cute little topics as that. He might call it 'Bachelor's future depends on the ratio of increase of automobiles.'" "I see!" exclaimed Andy with a chuckle. "Just as Darwin, or one of those evolutionists proved that the clover crop depended on old maids." "How do you make that out?" asked Dunk. "I guess you've forgotten your evolution. Don't you remember? Darwin found that certain kinds of clover depended for growth and fertilization on humble bees, which alone can spread the pollen. Humble bees can't exist in a region where there are many field mice, for the mice eat the honey, nests and even the humble bees themselves. "Now, of course you know that the more cats there are in a neighborhood the less field mice there are, so if you find a place where cats are plentiful you'll find plenty of humble bees which aren't killed off by the mice, since the mice are killed off by the cats. So Darwin proved that the clover crop, in a certain section, was in direct proportion to the number of cats." "But what about old maids?"