MICROBES, OB BACTEEIA. 127 



ascertained the presence of a microscopic plant, which 

 Ehremberg likewise found at Berlin in analogous cir- 

 cumstances, and which he named Monas prodigiosa. 

 At that time all microbes were confounded in the 

 Monad genus; we now term it Micrococcus pro- 

 digiosus. It has been observed not only on bread, 

 but on the Host, on milk, paste, and on all alimentary 

 or farinaceous substances exposed to damp heat. 



This microbe has been recently studied by Raben- 

 horst, who declares that it is polymorphic, and has 

 received a number of different names : Pahnella miri- 

 fica, ZoogalactiTia imetropha, Bacterium prodigiosum, 

 which are only varieties of Micrococcus prodigiosus, 

 modified by the medium in which it is nourished. 

 This observer noticed its appearance on cooked meat 

 kept in a cellar. The spherical cells, examined under 

 the microscope, were shown to be filled with a reddish 

 oil, which gave them a peach-blossom tint, and when 

 transferred to raw meat they assumed a splendid 

 fuchsia colour, resembling spots of blood. This plant 

 is only developed in the dark, and the nitrogen 

 necessary for its nutrition must be derived from the 

 air, especially when it is developed on bread, the 

 Host, etc., in which nitrogen is deficient. 



When it is said to rain blood, this phenomenon is 

 likewise due to the presence of a minute plant, prob- 

 ably similar to that which often gives a red tint to 

 ponds and reservoirs in autumn. This microscopic 

 alga appears to be the one discovered by Ehremberg in 



