MICROBES, OR BACTERIA. 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: Palmella miri- 
fea, Zoogalactina vmetropha, 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, ete., 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 
