Ancients infected by parasitical creatures evolved to become the Wraith.
A very remarkable instance of an acquired means of protecting a wound against parasitical invasion is to be found in granulations.
A plant or animal in perfect health is more resistant to parasitical invasion than one which is ill-nourished and weakly.
Each organism possesses within itself the means of protection against its parasitical enemies, and these properties are more in evidence when the organism is in perfect health than when it is debilitated.
When we consider that tuberculosis, diphtheria, cholera, tetanus, typhoid fever, anthrax, malaria and a host of other contagious diseases have each been proved to be of parasitical origin, an idea may be conve y ed of the range of the subject.