72 BACTERIA IN DAILY LIFE 



in the dark. It was found that typhoid, cholera, 

 and various other bacilli were most deleteriously 

 affected by insolation. Perhaps an example will 

 best serve to illustrate the nature of the results 

 obtained. Some boiled water contained in a flask 

 was inoculated with an immense number of a 

 bacillus, closely resembling the typhoid organism, 

 normally present in the body and frequently 

 found in water, the bacillus coli communis. So 

 many were introduced that nearly one hundred 

 thousand individuals were present in every twenty 

 drops of the water. This flask then, containing 

 water so densely sown with microbes, was placed 

 in the sunshine for one hour, whilst another and 

 similar flask was kept during the same time in 

 the dark. On being subsequently examined it 

 was ascertained that whereas a slight increase in 

 the number of bacilli had taken place in the 

 "dark" flask, in the insolated flask absolutely no 

 living organisms whatever were present. 



Professor Percy Frankland has also investi- 

 gated the action of sunshine on micro-organisms 

 in water, and in one of his reports to the Water 

 Research Committee of the Royal Society an 

 account is given of the effect of insolation on the 

 vitality of the spores of anthrax in Thames water. 

 These experiments show again what an impor- 

 tant influence the surroundings of the organism 



