SUNSHINE AND LIFE 71 



fashion of shutting the sunshine out by barriers 

 of blinds and curtains drawn across the windows, 

 a practice which seems to be almost entirely 

 independent of the habitual gloom of the sur- 

 roundings or general scarcity of sunshine, might 

 possibly be modified were it but known that by 

 thus excluding light we are conferring an in- 

 estimable benefit upon the members of the 

 microbial community, which may at any moment 

 comprise some of the subtlest and most danger- 

 ous antagonists with which we have to reckon 

 in the struggle for existence. 



From a hygienic point of view, also, the 

 question of the potency of sunshine in regard 

 to the bacteria present in water is both impor- 

 tant and interesting, for it is to water at the 

 present time that we look for the dissemination 

 of some of the most dreaded zymotic diseases. 



Comparatively little has been done in this 

 direction, but those results which have been 

 obtained are exceedingly suggestive. Professor 

 Buchner has published some preliminary experi-. 

 ments which he made with particular micro-organ- 

 isms. In these investigations boiled tap-water 

 was used to ensure the absence of all bacteria 

 except those which were subsequently introduced, 

 and, whilst some of the vessels were exposed to 

 the sunshine, others were simultaneously preserved 



