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Table IV Titration of Transforming Activity of Preparation 44

From: Studies on the Chemical Nature of the Substance Inducing Transformation of Pneumococcal Types

Transforming principle Preparation 44* Quadruplicate tests
  1 2 3 4
Dilution Amount added Diffuse growth Colony form Diffuse growth Colony form Diffuse growth Colony form Diffuse growth Colony form
10−2 1.0 + SHI + SIII + SIII + SIII
10−2.5 0.3 + SHI + SIII + SIII + SIII
103 0.1 + SHI + SIII + SIII + SIII
10−36 0.03 + SIII + SIII + SIII + SIII
10−4 0.01 + SIII + SIII + SIII + SIII
10−4.5 0.003 R only + SIII R only + SIII
10−5 0.001 R “ R only R “ R only
Control None R “ R “ R “ R “
  1. * Solution from which dilutions were made contained 0.5 mg. per cc. of purified material. 0.2 cc. of each dilution added to quadruplicate tubes containing 2.0 cc. of standard serum broth. 0.05 cc. of a 104 dilution of a blood broth culture of R36A is added to each tube.