Fermentation and Kindred Phenomena. 99 



either in their own tissues or in the medium upon which they 

 grow. At times the sudden and spontaneous appearance of 

 these organisms has created much wonder and awe. Thus, in 

 1819, "a peasant at Liguara, near Padua, was terrified by the 

 sight of blood stains scattered over some polenta which had 

 been made and shut up in a cupboard on the previous evening. 

 Next day similar patches appeared on the bread, meat, and 

 other articles of food in the same cupboard. It was naturally 

 regarded as a miracle and a warning from heaven until the case 

 had been submitted to a Paduan naturalist." * 



The cause was found to be due to a minute organism to which 

 the name micrococcus prodigiosus was given. It has been found 

 in milk, paste, and even sacramental bread, where its appear- 

 ance was of course considered miraculous. The colouring 

 matter is not contained in the organism itself, but is produced 

 by it in the medium in which it thrives. It somewhat resem- 

 bles aniline red (magenta or rosaniline) in its properties. 



Red Snow and Blood Rain are probably due to the same or 

 to a similar organism. At times milk is found to be quite blue — 

 a phenomenon of frequent occurrence on the German coast of 

 the Baltic. Formerly it was attributed either to a diseased 

 condition of the cow or to its consumption of vegetables con- 

 taining indigo. Fuchs, however, showed that it was caused by 

 an organism to which the name of bacillus cyanogenus was 

 given. 



Many other colour-producing organisms have been discovered, 

 of which the following may be mentioned : — 



Bacterium synxanlhum, in yellow milk. 



Micrococcus aurantiacus, occasioning orange patches at times 

 on cooked vegetables. 



Micrococcus cklorinus, producing green patches occasionally 

 on cooked vegetables. 



Micrococcus violaceus, &c. 



Any one can obtain these organisms (or at least some of them) 

 by exposing slices of potato (cut from potatoes well boiled in 

 their skins) for an hour or two to the air, and then preserving 

 • Troussart. Microbes, moulds, -&s. 



