BILE SALT BROTH 
I. A SIMPLE TEST FOR FAECAL CONTAMINATION 
II. THE BEHAVIOUR IN BILE SALT BROTH, IN CERTAIN SUGARS, 
AND IN GLYCERINE, OF SOME OF THE COMMONER ORGAN- 
ISMS—WITH SPECIAL REFERENCE TO THE EFFECT 
OF THEIR PRESENCE UPON THE VALUE OF 
THE ABOVE TEST 
By ALFRED MacCONKEY, M.B., D.P.H. 
AND 
CHARLES A. HILL, M.B., D.P.H. 
Assistant Bacteriologists to the Royal Commission on Sewage Disposal 
I 
In a previous number of these reports (T. T. Reports, vol. iii, part 2) 
one of us (MacConkey) described a medium which gives a most characteristic 
reaction when inoculated with B. coli communis or B. typhi abdominalis. This is an agar 
medium containing taurocholate of sodium and lactose. Upon this the colonies of 
B.C.C. grow freely and rapidly ; they assume a yellow colour and give rise to a fine 
precipitate in their vicinity — thus producing the appearance of a halo — on the other 
hand the colonies of B.T.A., though not usually apparent at the end of twenty-four 
hours, are after forty-eight hours plainly visible as whitish translucent roundish 
colonies without any surrounding haze. Further it was found that the medium was 
unfavourable to the growth of all the commoner forms of spore-bearing organisms — 
such as B. subtilis and its allies — which are usually present in water, whilst the 
temperature of incubation S3£~42°C. further inhibited the growth of most of the 
ordinary water bacteria. 
In order to simplify this test further — by the use of a fluid instead of a solid 
medium — a taurocholate glucose broth has been devised. 
The composition of the medium is as follows : — 
Sodium Taurocholate . . . 0*5 per cent. 
Glucose . . .-" . . 0"5 „ 
Peptone ..... 2*0 ,, 
Water . . . . . 100 cc. 
