Section IV., 1911. [31] Trans. R. S. C. 
The Bacterial Content of The Normal Udder. 
By F. C. Harrison and ALFRED SAVAGE. 
Bacteriological Laboratories, Macdonald College, P.Q., Canada. 
(Read May 17, 1911.) 
The experiments here described were undertaken in order to ascer- 
tain the species of bacteria which normally occur in the bovine udder; 
their means and time of entrance, and their action and importance. 
The dairy herd of the College furnished the animals for the experiments, 
and the laboratory work was carried out in our laboratories. 
Methods. In order to eliminate all chances of infection from animal, 
air, milker, etc., the milk was obtained directly from the udder by means 
of sterilized milk tubes. The apparatus, herewith illustrated, consists 
of a test tube or flask, fitted with a tight, two-holed rubber stopper. 
Through one hole passes a 4” milk tube and through the other a short 
piece of glass tubing plugged with cotton wool. This forms an escape 
forthe air. A close-fitting cap of cotton wool, tied with an elastic band, 
was used to cover the milking tube. The whole apparatus was always 
sterilized in live steam for thirty minutes before being used. 
The animal was first milked to the stage at which the sample was 
required, then the udder, flanks and thighs were thoroughly sponged 
with corrosive sublimate (about 1-700) and the teats washed with 27% 
lysol. In the case of the foremilk, a small stream was first drawn from 
each quarter to remove any mechanical dirt that might have been in 
the passage. The cap was then removed from the milk tube, which was 
immediately dipped in sterile vaseline and inserted into the teat: The 
flask filled of its own accord, no further manipulation being necessary. 
The milk from each quarter was drawn separately. When removed : 
from the teat the milk tube was again capped and taken to the laboratory. 
Neutral beef peptone agar, with the addition of 1% lactose was 
used, to which 1 c.c. of a neutral blue litmus solution was added at the 
time of making the plates. Agar was used in preference to gelatine, 
because the species encountered at any one time were few, and the results 
were more quickly obtained. 
For convenience in noting results, the teats were given the follow- 
ing numbers :— 
Right front, No. 1 Right hind, No. 3. 
Left yA OL CBE Left Core, 
