IN THE VICTORIAN ERA 7 



either the time or space in which to maintain a 

 large bacterial family, it is of immense convenience 

 to be able to obtain at a moment's notice a trust- 

 worthy culture, say, of typhoid or tuberculosis, or 

 specimens of obscurer origin from air or water 

 for purposes of investigation. These bacterial 

 cultures are all guaranteed pure, free from con- 

 tamination or admixture with other and alien 

 micro-organisms, and are strictly what they are 

 represented to be. Although such a declaration 

 is attached to many commodities at the present 

 day with ludicrous incongruity, in the case of 

 micro-organisms such a breach of faith is un- 

 known, and the antecedents of a microbe may be 

 said to be regarded as of as much moment and 

 to be as jealously preserved as is the pedigree of 

 the most ambitious candidate for honours at a 

 cattle or dog show ! 



Amongst some of the curiosities to be found on 

 the shelves of microbe-museums may be mentioned 

 bacteria which give out light, and thus, like glow- 

 worms, reveal themselves in the dark. These 

 light-bacteria were originally discovered in sea- 

 water and on the bodies of sea-fish, and cultures 

 of them have been successfully photographed, the 

 only source of light being that provided by the 

 bacilli themselves. The amount of light emitted 

 by a single bacillus might indeed defy detection 



