539 
1908-9.] The Pathogenesis of Micrococcus melitensis. 
Kennedy, and I fully confirmed this fact. The dog and the horse have also 
been infected experimentally, and there is very definite evidence to show 
that the cat, the cow, and the mule occasionally become infected under 
natural conditions, though none of these animals have so far been experi- 
mentally inoculated. 
Investigation by various members of the Mediterranean Fever Com- 
mission of domestic animals bred and maintained in Malta yielded evidence, 
by reason of the existence of specific agglutinins in the blood-serum, 
in support of the view that infection sometimes occurred naturally, and 
the results obtained may be conveniently tabulated here : — 
Animal. 
No. Examined. 
Serum Reaction 
at least 1 : 30 in 
M. melitensis 
recovered from. 
Horse .... 
100 
21 
nil. 
Mule .... 
94 
8 
nil. 
Cow .... 
33 
10 
2 
Goat .... 
2137 
847 
238 
Dog .... 
162 
4 
1 
Cat 
22 
5 
1 
Sewer rat 
129 
4 
nil. 
But it is interesting to note that the guinea-pig, which forms an article 
of diet among the lower classes in Malta and is bred for its flesh, does not 
appear to become infected naturally, as no evidence of disease could be 
detected in any of the 78 examined. 
Pathogenesis. 
The pathogenic effects noted in the various animals already enumerated, 
after inoculation with pure cultivations of M. melitensis, may now be con- 
sidered seriatim, and as my own observations in this connection have been 
fairly comprehensive, the descriptions are entirely derived therefrom. 
Pathogenic Effects produced by the Inoculation of M. melitensis 
into Various Animals. 
RODENTIA. 
Guinea-pig, Rabbit. 
The course of the infection in various rodents presents no material 
differences; hence where an experimentally inoculated guinea-pig is 
mentioned as illustrating a particular point, it must be understood that 
the behaviour of an experimentally inoculated rabbit would, under compar- 
able conditions, be identical, and vice versa. 
