148 



TRANSFORMATION OF PNEUMOCOCCAL TYPES 



A highly viscous solution of the nucleate in distilled water in a concentration of 1 

 mg. per cc. was used. 1.0 cc. amounts of heated and unheated sera diluted in saline 

 as shown in the preceding protocol were mixed in Ostwald viscosimeters with 4.0 cc. 



TABLE III 



Differential Heat Inactivation of Enzymes in Dog and Rabbit Serum Which Destroy the 

 Transforming Substance 



* Dilution of the digest mixture of serum and transforming substance. 



of the aqueous solution of the nucleate. Determinations of viscosity were made 

 immediately and at intervals over a period of 24 hours during incubation at 37°C. 



The results of this experiment are graphically presented in Chart 1. In the 

 case of unheated serum of both dog and rabbit, the viscosity fell to that of 

 water in 5 to 7 hours. Dog serum heated at 60°C. for 30 minutes brought about 



198 



