Death often occurred less than a week after infection. Pneumonic was the second most common form, and it infected the lungs. It also had a mortality rate of 95 percent, which seems impressive until you learn that Septicemic Plague, the third variety, had a mortality rate close to 100 percent, and even today there is no cure for it.
The only reason that the two latter examples were rare is because they killed so quickly that you didn't have time to pass it on before you died. Much like attacking Bruce Willis on Christmas, if you contracted Septicemic Plague, your life expectancy was about a day, and the end was not going to be pretty.
The Silver Lining:
The birth of the freaking modern world.
So how could one of the deadliest pandemics in human history have any positive outcomes?
Well, before the plague there had been massive overpopulation in many European countries, the likes of which the world really hadn't seen to that point. Along with it came famine, poor sanitation, overcrowding; all of which helped to accelerate the progress of infectious diseases like, well... like the plague. Disease, starvation and predators make up Mother Nature's three-pronged population control failsafe, and things had gotten to the point where it was going to be the Plague or lions.
So, what'll it be?