Normal values have been established for the levels of activity of lactic dehydrogenase,
isocitric dehydrogenase, glutamic-oxalacetic transaminase, glutamic-pyruvic
transaminase, aldolase and phospho-hexose isomerase in the plasma of
sheep emanating from areas in which geeldikkop and enzootic icterus are prevalent
and those raised in areas where the diseases do not normally occur. Some marked
differences between the two groups are apparent which support recent contentions
regarding the aetiology of the two syndromes mentioned.