Alexander's notes is a unique item in The Witcher 3: Wild Hunt and can only be received if you convinced Keira Metz to go to Kaer Morhen during For the Advancement of Learning. Once convinced, you can then ask for these notes without resorting to violence (if forced to kill Keira, Geralt will burn them instead).

Journal entry

-One droplet from a colony of plague bacteria diluted in one hundred quarts of pure water is sufficient to induce infection,
-In the absence of medical care, the illness terminates in death in 93% of cases,
-When medical care is provided, the illness terminates in death in 89% of cases,
-Individuals who survive develop complete immunity to the disease and never succumb to it again.
There are two interesting directions in which further research can proceed.
-Firstly, increasing the time during which the bacteria colony remains active after dilution (currently less than 12 hours) would allow for its use as a weapon, one idea for diversions or sabotage behind enemy lines.
-Second, the development of immunity in survivors suggests a vaccine may be possible.
Undertaking either of these would require an enormous dedication of time and means, neither of which, sad to say, I possess at the moment.

Associated quest

Community content is available under CC-BY-SA unless otherwise noted.