The concept of chemotherapy as originated by Paul Ehrlich is based on the premise that antiparasitic drugs must have two properties: they must first bind to specific structures of the parasite which Ehrlich called chemoreceptors. Subsequent to their attachment to the chemoreceptor and by virtue of this binding they must possess the capacity to kill the parasite. Since the host which is to be cured of an invading parasite also contains a large number of chemoreceptors, that have the potential to bind toxic compounds, the task of the chemo therapist is to identify chemoreceptors of the parasite...