Living Type lIS bacteria recovered Living Type IlS Live mouse 肺炎双球茵 S型 R型 Capsule Dead mouse Heat-killed Type llIS Live mouse o Live mouse Living Type lIR Live mouse o No capsule Live mouse Living Type IIS Heat-killed Type IlIS bacteria recovered IIS Living Type lIR Live mouse ILR Dead mouse Figure 10.2 Griffith's discovery of transformation in Streptococcus pneumonine