208 
With regard to cows the evidence is not so clear. Kept shut up ; 
in “ shippens,” and seldom allowed outside, they have their food ! 
brought to them, but as this food is composed of vegetable and ■ 
other refuse collected from every possible source and situation, it is 
easy to understand that they can hardly escape from receiving i 
infected food from time to time. 
It was interesting to note whether those goats whose blood gave i 
a positive agglutination reaction would have some symptoms of 
illness, but this was not apparent except in a few cases. The quan- 
tity and quality of the milk seemed in most cases to be unaffected. 
In fact, it was often noted that the best milk-producers in the herd I 
gave a positive reaction. 
Horrocks and Kennedy ® thought that as a result of their observa- 
tions, judged by the serum reaction, 41 per cent of the goats in Malta I 
are infected. Ten per cent of the goats supplying milk to various 
parts of Malta ajDpear to excrete the JI. melitensis in the milk. 
The excretion of the specific microbe may continue steadily for three ] 
months without any change occurring in the physical character or 
chemical composition of the milk and without the animal exhibiting j 
any signs of ill health. Some infected goats may lose flesh and their 
coats become thin ; they may also suffer from a short hacking cough. i 
A febrile condition, however, has not been observed. Goats may 
haAn a marked blood reaction and yet never excrete the JI. meli- 
tensis in the milk. If the blood serum or milk does not agglutinate 
the JI. melitensis.^ the specific microbe is not found in the milk. 
The excretion of the JI. melitensis in the milk may be intermittent, 
api^earing for a feAv days and then disai^pearing for a Aveek or more. 
A blood reaction may exist for some Aveeks before the JI. melitensis is 
excreted in the milk. 
Monke}"S and goats can be infected by feeding with cultures of 
JI. melitensis isolated from milk, and also b}" feeding Avith infected 
milk itself. The incubation period in feeding experiments appears to 
A^ary between three and four weeks. Monkeys infected by feeding 
sometimes suffer from a typical AvaA^e of fever and lose flesh, at other 
times they show no obvious signs of ill health, and may even gain in 
Av eight. 
IVhen monkeys become infected by feeding Avith milk the lymphatic 
glands always contain far more colonies of the JI. melitensis than the 
spleen. This fact suggests that the specific micrococci contained in 
the food are carried to the hunphatic glands and there undergo con- 
siderable multiplication. It has not yet been proA^ed that the mesen- 
teric glands are always infected at an earlier date than the femoral 
® Reports of the commission * * * for the investigation of Mediterranean 
fever * * * Part 4, 1906, p. 68, et seq. 
