PLATE 1 



Multiplication of the Ultramicrobial Bacteriophage 



A bacterial suspension is inoculated with one-billionth of a cubic centi- 

 meter of a filtrate containing the Bacteriophage. From time to time one- 

 fiftieth of a cubic centimeter is taken from this suspension and spread on 

 agar. After a period of incubation of the agar tubes the following results 

 are obtained (reading from left to right). 



Tube 1. Planting made immediately after the inoculation of the bac- 

 teriophage. A normal bacterial culture results. 



Tube 2. Planting made 1 j hours after the inoculation. A normal bac- 

 terial culture results. 



Tube 3. Planting made 2\ hours after the inoculation. The layer of 

 bacterial growth shows three colonies of the bacteriophage. 



Tube 4. Planting made 3f hours after the inoculation. Confluent 

 colonies of the bacteriophage are disseminated throughout the bacterial 

 growth. 



Tube 5. Planting made after 5 hours. There is no evidence of bacterial 

 growth, the number of ultramicrobes being such that all of the bacterial 

 elements were destroyed. 



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