70 BACTERIA IN DAILY LIFE 



were carried out was in some cases kept in a 

 dark cellar, whilst in others it was left standing 

 in the laboratory in ordinary daylight. 



Delicate bacteria, such as the fowl -cholera 

 bacillus, it was found, could not survive exposure 

 to daylight in this dried-up condition for more 

 than ten hours, but when they were put in the 

 dark their lease of life was prolonged for more 

 than twice that length of time ; whilst as regards 

 varieties of tougher constitution, such as diph- 

 theria and tubercle bacilli, whose initial vitality 

 was very considerably greater under these adverse 

 circumstances, confinement in the cellar enabled 

 them to exist more than four times as long as 

 they were able to in the healthy atmosphere of 

 the well-lighted laboratory. 



Dr. Onorato, of the University of Genoa, has 

 recently shown, also, that influenza bacilli are 

 entirely destroyed after the sun has 'been shining 

 on them continuously for three and a half hours. 



Such facts indicate how essential to health is 

 plenty of light in our dwelling-rooms, and how 

 important it is that in the designing of houses 

 the trapping of the maximum amount of sun- 

 shine should be very carefully considered. Archi- 

 tects might indeed with advantage be compelled 

 to include in their qualifications a knowledge of 

 the fundamental facts of sanitary science. The 



