Penicillin in Weil's Disease

Studies on Leptospira Icterohaemorrhagiae. Ii. A Critical Study of the Effect of Penicillin on Leptospira Icterohaemorrhagiae in Vitro and in Leptospirosis in Guinea Pigs

“…5 It must be noted that the 2 animals in Group 1 that recovered when penicillin was given shortly after the animals became sick, showed definite improvement on the 2nd day of treatment, and returned to normal on the 3rd day. Those animals that died in spite of the treatment, showed no apparent improvement in symptoms.…”