The phenomenon of the "bleeding host", so often regarded as 

 a miracle in the Middle Ages, was due to a similar cause. The 

 composition of the sacramental bread, rich in starch and poor in 

 acid, was well adapted to the rapid growth of Schizomycetes ; but 

 the popular explanation of the phenomenon was that the host had 

 been stabbed by unbelieving Jews. The number of executions 

 and murders due to this belief was so great that Scheurlen, in 

 alluding to it, remarks that "dieser Saprophyt mehr Menschen um- 

 gebracht hat als mancher pathogene Bacillus". 



Three nineteenth century appearances of this "blood miracle"' 

 as epidemic in a town or neighborhood are of interest. In the 

 year 1819, at Legnaro, near Padua, Italy, the whole district was 

 set in commotion by the appearance of red spots upon food. An 

 investigation was undertaken by physicians and professors of the 

 University of Padua, the fungus nature of the growth was dis- 

 covered, and two separate names given to it. B i z i o (23) called the 

 organism Serratia marcescens, the Serratia in compliment 

 to the savant who first propelled a boat by steam on the Arno. 

 His generic description is of interest: - -"Funguli acaules, senri- 

 sphaerica, capsulis contortis. Serratia marcescens. Vesicula tenuis- 

 sima, latice primo roseo, dehinc rubro repleta." Bizio reprinted 

 his paper of 1823 in volume I of his Opuscoli chimico-fisico, 

 1827, and several times later asserted his claim to priority in the 

 investigation of B. prodigies us. Meanwhile, the same epidemic 

 of Legnaro had been reported by Sette (25), and the name of 

 Zoogalactina immetropa given to the organism. More than 

 twenty years later, in January 1844, there appeared in the Jour- 

 nal de Pharmacie a report by various members of the French 

 Academy of Sciences, who had been commissioned to investigate 

 a reddening of the munition bread which was exciting among the 

 French soldiery much the same agitation as had prevailed among 

 the troops of Alexander. This report, and the treatment of the 

 phenomenon as new, brought out a letter from Bizio (24), emphasi- 

 zing his work of twenty-four years earlier, and giving the reference 

 to it. However, the next noteworthy epidemic of the sort in 

 Berlin in 1848, investigated by Ehrenberg (26), has not only 

 fixed upon the organism the name Prodigiosus then given to 

 it, but has connected the name of the German scholar with its 

 discovery. 



Since Ehrenberg 's monograph many investigators have dealt 

 with the biological characteristics and the pigment of B. prodi- 

 giosus. A differentiation among the red germs was introduced much 

 later; thus, B. ruber indicus was first described in 1884, 

 B. ruber plymouthensis by Fischer in 1887, B. mesenteri- 

 cns ruber (Globig) in 1888, and B. lactis erythrogenes 

 (Hueppe) in 1889, etc. 



B. prodigiosus (Ehrenberg). 



This most common of all the pigment forms has been so com- 

 pletely described within the last few years that I can add little 



