Some Bacterial Curiosities 5 1 



which life, slowly emerging from its primeval 

 simplicity, at last came to be manifested in 

 that grand scale of living beings at the top 

 of which man stands supreme, are still to be 

 traced way down among the invisible or- 

 ganisms which typify the earliest and sim- 

 plest expression of life. 



But certain of these color-forming bacteria 

 are sometimes very disagreeable intruders 

 upon domestic life. Occasionally, without 

 warning, the milk of a particular dairy 

 suddenly develops a very uncanny deep-blue 

 color, which, like an epidemic, spreads to all 

 the milk which is stored in special rooms. 

 This occurrence, for a long time a disagreeable 

 and costly mystery, is now known to be due 

 to a tiny bacterium of the genus Bacillus? 

 which, floating about in the air with the 

 dust, from time to time infects rooms, and, 

 falling into the milk, grows there, producing 

 the blue coloring matter. 



Sometimes milk gets red instead of blue, 

 and then the change is due to another form 

 of bacteria floating with the dust. Bread, 

 too, may become infected in the same way, 



