BACTERIA IN PUBLIC SWIMMING BATHS 
97 
liquefiers of gelatine were under one per cent. We never succeeded in discovering 
streptococci, probably because the colonies on agar plates are small and difficult to 
identify, but, perhaps, because streptococci are difficult organisms to cultivate. 
Staphylococcus aureus and citreus were very rare, and totally absent in the vast 
majority of plates examined, even though the plates were kept for a week or more, 
in order that the colonies, if present, might develop their characteristic colour, and 
thus be easily identified. Other staphylococci were present in large numbers, and 
comprised three varieties, Staphylococcus pyogenes albus, Staphylococcus epidermidis albus 
of Welch, and Staphylococcus cereus albus. A rough idea of the frequency of staphy- 
lococci in salt water at the end of the day may be gathered from the following 
observations : — 
Five agar plates contained a total of one hundred and one superficial colonies ; 
twenty-three of these proved to be staphylococci — eleven Staphylococcus cereus albus, 
eight Staphylococcus pyogenes a/bus, four Staphylococcus epidermidis albus. 
A number of observations were made on the occurrence of B. colt communis, 
for these organisms are a rough index of faecal contamination. Now it is by no 
means a simple task to identity a colony of coli on an agar plate containing colonies of 
other organisms. Fortunately we wereable to employ bile salt agar, amedium synthesised 
by Dr. MacConkey (+) in this laboratory. Colonies of colon bacillus have a most 
characteristic appearance on this medium, so their identification is a comparatively easy 
matter ; the medium was tested by working out cultural characteristics of at least 
eighty colonies which resembled B. coli. The result was eminently satisfactory. By 
B. coli we mean Escherich's coli, also another B. coli very closely allied to it, which differs 
in this respect, it forms acid and gas in cane sugar. The media used in testing bile 
salt agar and in identifying B. coli were glucose, lactose, mannite, and cane sugar 
broths and litmus milk ; the motility, the staining reaction by Gram's method, and 
the method of growth in gelatine were tested in each individual instance. 
B. coli was present in the bath at the end of day, 2" 15 per c.c. in the first class, 
and 8 - 9 per c.c. in the second class. It was always absent in the clean water. It does 
not exist in the air, as Miss Chick' 51 points out in her article on the Distribution of B. coli 
communis, therefore it could not have dropped into the bath, so its presence is an indication 
of faecal pollution from material which was derived mainly from the bodies of the bathers> 
but as we found also in small part from the fragments of horse manure, which, being 
deposited on the surface of the corridor, were carried into the baths. The bacillus 
multiplied slightly in salt water during the dav, no observations were made with 
reference to its multiplication in fresh water. The number of coli carried in by each 
bather in a first class bath was approximately two million four hundred thousand ; in 
a second class bath exactly double. 
Is swimming bath water, containing several thousand of bacteria per c.c, 
mainly derived from the human body, injurious or likely to be injurious to those 
bathing in it ? 
