79 
MICROCOCCUS MELITENSIS. 
Maj. W. H. Horrocks and Capt. J. C. Kennedy, of the British Army 
Medical Corps, in their article upon goats as a means of propagating 
Mediterranean fever,® made several experiments to determine whether 
it is possible to destroy the M. melitensis by pasteurization of the 
infected milk, and concluded that heating the milk to 68° C. for ten 
minutes destroyed the M. melitensis present in infected goats’ milk. 
No record, however, is made of experiments with lower temperatures. 
■Experiment 1. — Milk was drawn from goats 1, 2, 3, 5, and 6 and thoroughly mixed. 
This mixed milk was selected for experiment as it contained thick, ropy masses, and 
it was thought that these might act as protecting envelopes to the specific micrococci, 
so that if such a milk were sterilized by pasteurization it might safely he concluded 
that any ordinary normal-looking milk would be equally sterilized by the same 
operation. 
One loopful of the mixed milk was stroked on a series of surface plates to act as a 
control. The mixed milk was then heated on a water bath to 68° 0., and this tem- 
perature was maintained for ten minutes. The milk was tlien rapidly cooled and 
10 c. c. of the sterilized milk were spread over 20 litmus-nutrose-agar plates. 
Results: After four days incubation at 37° C. the control plates were found densely 
crowded with colonies of the M. melitensis; the plates made from the pasteurized milk 
remained free from any signs of the specific Micrococcus melitensis, even though the 
incubation was continued for fourteen days. 
Experiment 2. — this served as a control of experiment 1, the same procedure being 
followed. The Micrococcus melitensis appeared in the control plates, but the plates 
made with the pasteurized milk again remained perfectly sterile. 
In my experiments I used two strains of the M. melitensis. The 
results follow: 
Experiment No. 56. 
M. melitensis. 
Culture, seven days’ growth in bouillon, mixed wdth milk that had been inoculated 
the previous day with same culture. Reaction of milk, 0.081 per cent acid. 
The milk at 31° C. immersed in constant-temperature water bath at 55° C. 
Milk culture. 
Temper- 
ature 
(°C.). 
Loop of milk 
culture in agar. 
At start 
31 
Innumerable. 
IJ minutes, after immersion 
4.5 
Do. 
minutes after immersion 
48 
Do. 
If minutes after immersion 
50 • 
Do. 
2 minutes after immersion 
51 
Do. 
2j minutes after immersion 
.52 
Do. 
2s minutes after immersion . . 
S3 
Do. 
3 minutes after immersion i . . 
54 
Do. 
4 minutes after immersion 
55 
Do. 
“Horrocks, W. H., and Kennedy, J. C.: VI. Goats .as a means of propagation of 
Mediterranean fever. Reports of the commission * * * for the investigation of 
Mediterranean fever * * * Part 4. London, Harrison & Sons, Feb., 1906. 8° 
Paper. 187 p. 
31865— Bull. 42—68 6 
