FIG. 1.

E. coli and bacteriophage R in blood (a) and feces (b) of colostrum-deprived calves. •, E. coli in control (untreated) animals; ○, E. coli in animals to which phage was administered intramuscularly 8 h after E. coli infection; □, bacteriophage counts in phage-treated animals. Triangles indicate time at which control (▴) or treated (▵) calves were killed. Dashed lines indicate the limit of sensitivity of the bacterial counting method.