34 
Houston. The following para. gives the results quoted from 
his 5th Research Report :— 
‘‘ Tests were also made to determine the number of 
weeks, during which these 100 streptococci sustained their 
life in Pasteur-filtered West Middlesex main tap water. About 
100,000 of each of the 100 varieties of streptococci were added 
separately to 100 tubes, each containing Io c.c. of the water 
sterilised by ‘ Pasteur-filtration ’ and I c.c. cultures made 
therefrom each week. 
‘The tubes were kept in a dark cupboard the temperature 
of which varied from 46 to 61 degrees Fahrenheit during the 
progress of the experiments. 
The following is a summary of the results fom 
3 per cent. died in 1 week. 
a 6 i C 2 weeks. 
32 >? 2) 3 9) 
SEE) Fs avy 2 ener 
8 : ght ie UP ies 
4 ” ” 6 ” 
2 y ne Be eis 
I i, still alive in 9 weeks. 
r tube became contaminated. 
‘In my 1903-04 report to the Local Government Board, 
previously referred to, it was shewn that although some of 
the fecal streptococci of experiment died very speedily in 
sterile tap water and sterile salt solution, others persisted for 
a long time, and I was unable to associate satisfactorily this 
variability as regards vitality with differences in the bio- 
logical characters of the streptococci. 
‘It must be admitted that these vitality results appear 
to ‘clash ’ with the observed fact as regards the paucity 
of streptococci in raw river water. 
Nevertheless, the behaviour of fecal streptococci in 
sterile water is not to be taken as necessarily measuring the 
vitality of these micro-organisms when in competition with 
a multitude of other microbes in raw river water.”’ 
It would appear that the varieties of streptococci used 
(they appear to be laboratory cultures and pure) retain 
