Possible Clues:

• University man tries to create the bloody stuff
• Source of immunity
• Nature is adapting, beginning to make medicinal fluid
• Team is run in order to get medical substance
• I'm nature's fluid remedy for disease
• Medicinal fluid: sick man rues swallowing it up
• It provides immunity
• Remarkably, it's manure giving protection from disease
• Plant containing source of this unusual medical treatment
• Possible treatment, mixture of tisane and rum