218 
Mediterranean fever, often called “ rock fever,” has existed in Gi- 
braltar for many years,® although the cause of the fever was not known 
until the discovery of Bruce’s specific organism from fatal cases of 
Malta fever. Physicians residing in Gibraltar knew of the existence 
of a fever characterized by long duration, low mortality, and liable 
to be followed by rheumatic sequela. 
In a study of the cases of continued fever in Gibraltar from 1882 
to 1905 it was shown by Horrocks that in the year 1884 there were 
833 cases of continued fever of which 429 were probably Mediterra- 
nean. In 1885 there were 697 cases of continued fever including 341 
cases of Malta fever. In 1886 there were only 331 cases of continued 
fever and of. these 158 were enteric fever. The great increase in the 
number of cases of enteric fever was attributed partly to the arrival 
of an infected regiment in Gibraltar from Egypt and to serious sani- 
tary defects in Gibraltar. In 1887 there was again a considerable 
falling off in the number of cases of Mediterranean fever and from 
that date, with slight oscillations, the curve of Mediterranean fever 
gradually declined until it reached 0 in 1904. The rapid disappear- 
ance of febrile diseases from Gibraltar, which commenced in 1885, 
forms a marked contrast with the state of things in Malta in cor- 
responding years. It is plain that some important factor which dis- 
appeared from Gibraltar has continued to operate in Malta. 
It has been shown that the M. melitensis is excreted in the urine of 
man and goats and that animals can be infected by dust contami- 
nated with the urine of Malta fever patients ; that the micrococcus is 
excreted in the milk of infected goats, and that the consumption of 
this milk causes Malta fever in monkeys. It is evident that both the 
sanitary conditions and the possible infection of goats in Gibraltar 
must be investigated if the cause of the continued fever is to be 
discovered. 
That the improvement of the sanitary conditions played but a 
minor part in the marked decrease in the prevalence of Malta fever 
in Gibraltar is shown by the fact that the curve representing the 
presence of Malta fever among the military population rose steadily 
from 1874 to 1884, in spite of the improvement in the sanitary condi- 
tions in Gibraltar. 
Twenty years ago goats were allowed to graze on certain portions 
of the rock and passes were granted to goat keepers for this priv- 
ilege. In 1883 passes for 1,793 goats were granted. In 1886 the 
number of passes had been reduced to 1,512; by 1890 the passes had 
further declined to 590, and in 1892 to only 510. From 1894 to 1902 
the number of goats appears to have changed very little ; in 1904 the 
° Reports of tlie commission * * * for the investigation of Mediterranean 
fever * * * Part 5, 1907, p. 55. 
