Cultivation of Theileria. II. Attempts to cultivate erythrocytic stages of Theileria mutans

Blood from calves with a parasitaemia of Theileria mutans was cultivated in vitro in various ways. No significant increase in the percentage of infected red cells was observed, but the percentage of dividing forms of the parasite rose sharply during the first two days of incubation. The conditions of the cultures were apparently unsuitable for the invasion of erythrocytes.