THE BIOLOGY OF MICROBES, ETC. 



115 



fied. As the temperature rises to blood-heat M. 

 prodigiosus loses its power of forming the red pig- 

 ment ; but forms casein, lactic acid, and probably 

 other substances. ' When growing and kept in the 

 depth of a solid nourishing material, i.e. removed 



A, Macroscopic 

 appearance of Mic- 

 rococcus prodigiosus 

 on sterilised potato 

 after four days' cul- 

 tivation. From a 

 fifth fractional cul- 

 tivation. 



C, Microscopic 

 appearance of M. 

 prodigiosus. 

 X 1265.? 



B, A growth of Micrococcus 

 prodigiosus in nutrient agar- 

 agar. 



Fio. 30. MICROCOCCUS PRODIGIOSUS. 



from the free surface, colonies of this microbe grow 

 as colourless micrococci.' They are always present 

 in the atmosphere, and give rise to the phenomena 

 known as ' bleeding bread,' ' blood-rain/ ' bloody 

 sweat,' etc. 



