The ion exchange adsorption system at the left is part of a portable unit for extracting usable antimalarial from freshly stripped cinchona bark, in the field.

of the Engineer Board, and has been considered by members of the Engineer Board, 2. This report covers the research and development of a process and portable plant for the field extraction of cinchona alkaloids. 3. The report concludes that acid extraction of cinchona alkaloids, followed by ion exchange recovery, is an efficient process from both an economic and logistic standpoint^ that the process can be carried on in a completely portable extraction plant; that acid extraction followed by alkali precipitation is a usable process where the efficiency and logistics of the method are not controlling factors; that the end product of either of the above methods constitutes a usable antimalarial; that the acid extraction-ion exchange process is directly applicable to the extraction of most of the usable alkaloids; and that the component parts of the field unit have functioned satisfactorily when uüed individually for other comparable purposes, but that the unit as a whole should be subjected to rigid field tests. 4. The Engineer Board concurs in the recommendations of the report, namely, that: a. The two existing pilot plants designed and constructed at the Engineer Board be subjected to a rigorous field testing program by the officers of the Cinchona Research Unit. b. In conjunction with this field testing, a field manual covering the extraction process and the operation and maintenance of the portable plant be written during pilot plant operation and translated into the required languages« c. Research on ion exchange capacities now in progress at the Engineer Board be carried tc 5. An advance letter report on the subject development was submitted by the Board on 20 June 1945 in the interest of permitting expedited action to be taken with respect thereto prior to the submission of the complete report. The attached completed report is consistent with the advance letter report previously submitted and contains the conclusions and recommendations made therein. FOR THE BOARD: