CHROMOGENIC BACTERIA 1 97 



In the Church of St. Genaro in Naples twice a year a crytsal 

 vial containing a solid substance of a dark color was exposed in 

 the early days under a glass case to the gaze of the people. 

 This was declared by the priests to be the blood of St. Janarius, 

 which could be changed from a solid to a liquid in one night. 

 When General Championet, commanding the French, entered 

 Naples in 1799, the miracle of the liquefaction of the blood was 

 not performed and there was great dissension among the 

 people. The monks declared that the liquefaction was the 

 work of God, and that they could not bring it about. How- 

 ever, General Championet informed them that the miracle 

 must take place at a definite time under penalty of death. 

 The miracle took place as desired, and it was found that the 

 monks possessed a substance which they kept from year to year 

 which when added to gelatinous material would bring about 

 a liquefaction. We now know that, unknown to them, the 

 monks had a culture of Bacillus prodigiosus, which produces 

 a proteolytic enzyme capable of liquefying gelatin. The same 

 bacterium has been noted on bread in damp churches, on oil 

 paintings, etc., and was interpreted to be the blood of Christ. 



