Mason, J.H.Alexander, R.A.Du Toit, P.J.2016-07-132016-07-1320161939Mason, JH & Alexander, RA 1939, ‘Studies of the Rickettsias of the Typhus-Rocky-Mountain-Spotted-Fever Group in South Africa. IV. Discussion and classification’, Onderstepoort Journal of Veterinary Science and Animal Industry, vol. 13, no. 1, pp. 67-76.0330-2465http://hdl.handle.net/2263/55670The articles have been scanned in colour with a HP Scanjet 5590: 300dpi. Adobe Acrobat XI Pro was used to OCR the text and also for the merging and conversion to the final presentation PDF-format.1.The five strains of rickettsia are discussed and compared according to the criteria suggested by Pinkerton (1936). 2. It· is concluded that they fall into two groups: (a) Typhus group – endemic, murine or rat typhus. (b) Rocky Mountain spotted fever group - fievre boutonneuse, strains “Robertson”, “Appleton”, “Hare”, which are similar and show only minor strain differences. 3. A proposed nomenclature is discussed.en© ARC – Onderstepoort and Faculty of Veterinary Science, University of Pretoria (original). © University of Pretoria. Department of Library Services (digital).Veterinary medicineVeterinary medicine -- South AfricaArticle