44 The Story of the Bacteria 



boarding-house breakfast- table. To the con- 

 sternation of the maid who went into the dark 

 cellar for them in the early morning, there 

 hung in the place of the sausages a fiery 

 effigy which seemed to her more like the 

 quondam spirits of their mysterious ingredi- 

 ents than the unctuous homely friend of the 

 homeless boarder. 



The explanation of this is now simple 

 enough without recourse to the supernatural; 

 for it has been recently shown that this 

 curious light which various organic sub- 

 stances emit is due, in many cases at least, 

 to the enormous numbers of certain kinds of 

 bacteria which are present on their surfaces, 

 hard at work feeding on the organic com- 

 pounds which are present and undergoing 

 decay. Pure cultures of these singular bac- 

 teria have been made and cultivated in con- 

 siderable quantities. These bacterial masses, 

 together with the tubes in which they were 

 growing, have been placed in a dark room 

 with an open watch beside them, and bacterial 

 masses, tubes, and all actually photographed 

 by their own light, the pointers of the watch 



