A fox went to ground, and a terrier called 'Scamp" was put in, and they heard him working. Suddenly a strong smell of skunk came from the hole, and all sound ceased. They dug down and came upon the dog -- dead, while a foot beyond was the fox, also dead. Behind him the skunk - alive. Both fox and terrier had been suffocated by the skunk fumes. The dens in this country are mostly enlarged woodchuck holes. The earths are sometime rocky, sometimes in clay, sometimes in sand. Drains are never used as regular earths.
Well he got that right! Here in the U.S. our holes are tight, and we generally do not have to work drains.
As for the fox, it is hardly the most dangerous thing to be found underground in the country.
Along with the rare rattlesnake, copperhead, and black widow spider, we have skunks. In fact, more working terriers in America die from skunk fumes than anything else.
Suffocation is only part of the issue; unadulterated skunk spray itself is toxic when breathed in large amounts underground. The result is "skunk toxic shock syndrome" in which the red blood cells of the dog exploded, causing Heinz Body Anemia.
Skunk Toxic Shock is an emergency problem unique to working terriers; it does not occur if a dog is simply sprayed above ground. For more information, click here and here and here.