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

Table IV Titration of Transforming Activity of Preparation 44

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
10⁻³	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 “

* 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 10⁻⁴ dilution of a blood broth culture of R36A is added to each tube.

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