DISEASES OF GOATS, DOGS, AND CATS 637 



subsequent formation of white flocculent sediment without the for- 

 mation of a pellicle. In litmus milk the medium is not coagulated, 

 and in ten days to two weeks the milk becomes distinctly alkaline. 

 Indol is not produced. It is pathogenic to monkeys by subcutane- 

 ous injection, but, according to Durham, rabbits and guinea pigs 

 are only susceptible to an intracerebral inoculation. 



Malta Fever in Man on the Island of Malta. On the Island of 

 Malta there has been endemic for an indefinite period a febrile dis- 

 ease of the inhabitants termed Malta fever, and also known as Rock, 

 Mediterranean, or undulant fever. It is a specific infectious disease 

 caused by the Micrococcus melitensis discovered by Bruce in 1887, 

 and is characterized by an irregular fever of an undulating type, 

 with frequent remissions and relapses, constipation, excessive per- 

 spiration, and joint pains, rheumatic in character. It runs a pro- 

 tracted but indefinite course of from three months to a year, with 

 a low rate of mortality of about 2 to 3 per cent. 



This disease, which resembles typhoid fever very closely, was so 

 exceedingly prevalent among the British soldiers and sailors stationed 

 on the island that in 1904 a commission was appointed by the Eng- 

 lish Government, under the supervision of an advisory committee 

 of the British Royal Society, to investigate the possible sources of 

 infection and advise methods for its control. The commission in- 

 vestigated the disease in all of its phases in a most exhaustive man- 

 ner, and was led to consider that the milk from Maltese goats was an 

 important, if not the main, factor in the dissemination of Malta 

 fever among human beings. The subsequent experiments showed 

 that a large proportion, reaching upward of 50 per cent, of the 

 20,000 goats on the island were affected with the disease. 



Infection by Means of Goats' Milk. Zammit noted early in 

 1905 that the Maltese goats were to some extent affected by Malta 

 fever after they had been fed on living cultures of the Micrococcus 

 melitensis. This observation was later confirmed by the finding 

 that the goats were not only able to be artificially infected but that 

 about 50 per cent of them acquired the disease naturally, and that 

 the organisms were eliminated in their milk and urine. It was then 

 decided to investigate the milk of such infected though apparently 

 healthy goats with the result that in Malta 10 per cent of the 

 goats were found to be eliminating the specific coccus in the milk, 

 and this milk when fed to monkeys even for a day was able to pro- 

 duce typical attacks of Malta fever which ran a course parallel to 

 that of the disease in man. The only logical conclusion which 

 could be formulated from this work was that the Maltese goats were 

 carriers of the virus of Malta fever and one of the principal means 

 of transmitting the disease to human beings through the ingestion 

 of their milk. 



All the available evidence points to contaminated food as the 

 vehicle by which these goats become infected with the virus of 

 Malta fever. It has been definitely established that monkeys and 

 goats may be infected in this manner. Furthermore, it has been 

 shown that the urine of infected goats and of ambulatory cases in 



