The result of these widespread observations was the confirmation in every respect of Laveran's discovery of the association with malaria of a protozoan parasite.

This was step number three.

Clinical observation, empirical discovery of the cure, determination of the presence of a parasite.

Two other steps followed rapidly.

Another army surgeon, Ronald Ross, working in India, influenced by the work of Manson, proved that the disease was transmitted by certain varieties of mosquitoes.