Induced malaria has established itself as a therapy of significant value in the treatment of dementia paralytica. For several years prior to our entry into the study of malaria therapy, there was an anxious desire to use malaria in the various state institutions for the insane. At the Austin State Hospital induced malaria was studied prior to 1933. The results, while encouraging, met with technical difficulties. It was impossible to carry a strain of benign tertian malaria through more than three or four hosts by means of blood inoculation. The clinical results were encouraging and a desire was expressed to further the study of malaria therapy by direct inoculation from infected mosquitoes. Boyd (1) had demonstrated the value of using the McCoy strain of malaria parasites and had proven that a colony of mosquitoes A. quadrimaculatus could be kept available at all times, ready for inoculation purposes.