Back in the day, students were taught the important subjects at school, such as how to kill rats. Here's a description of rat-killing lessons at the Farm and Trade School on Thompson's Island
, circa 1907. From Rats and Rat Riddance
(1914), by Edward Howe Forbrush:
At the Farm and Trade School on Thompson's Island, where the boy pupils are taught to kill rats, as all boys should be, there is a henhouse built with a cement foundation, but it has an earth floor and no foundation wall on the south side; therefore it is not rat-proof. The wooden floor of the main house is raised about three feet above the earth, leaving a space below it for a shelter for geese. Here the rats have burrowed in the earth, and as it was considered unsafe to use carbon bisulphide there on account of the fire danger, water was suggested. Two lines of common garden hose were attached to a near-by hydrant, the ends inserted into rat holes and the water turned on. All rat holes leading from the henpens to the outer world were closed with earth, and several boys were provided with sticks, to the end of each of which a piece of hose two feet long had been attached. A fox terrier was introduced into the henpens, and in about half an hour the rat war began. As the half-drowned rats came out of their holes somewhat dazed they were struck by side swings of the hose sticks, which knocked them off their feet, to be killed by other blows. If one escaped into the henpens, boy or dog killed it. This operation was repeated later from time to time. Four successive battles several weeks apart yielded 152 rats from under and about this henhouse, and no doubt many young rats were drowned in their nests. Where no high-pressure water main is available burrows on the banks of pond, river or ocean might be cleared in this way by means of a powerful sewer pump and hose.
The pictures show the schoolboys showing off their kill, as well as the rats strung up.