694 ' A MANUAL OF BACTERIOLOGY 



shown that the main source of infection of man is by goat's milk, 

 Goats may be infected (and are largely so in endemic districts, 

 e.g. Malta and South Africa) without showing any symptoms, 

 and excrete the organism in large numbers in their milk. Since 

 goat's milk has been boiled the incidence of .the disease in Malta 

 has fallen from 663 cases in 1905 to seven cases in 1907 in the 

 Army, and in the Navy there were no cases in 1907 (Bruce). 



Toxin, vaccine, and serum therapy. The M . melitensis forms no 

 extra -cellular toxin, but Macfadyen obtained an endotoxin by 

 disintegration. Attempts to prepare an anti-serum have not been 

 successful. A vaccine prepared with cultures killed by heat (see 

 p. 265) has been used in the chronic form of the disease by Bassett- 

 Smith 1 and others with some amount of success (dose 100 to 

 500 millions). 



An organism, the M. paramelitensis, has been found by X<\uir 

 and Kaynaud in certain cases of undulant fever. In such cases, 

 the blood may not agglutinate the M. melitensis but does agglu- 

 tinate the M. paramelitensis. A case of this kind is recorded by 

 Bassett-Smith. 2 As regards treatment, yeast or yeast-products 

 have been found of service in the neuritis of the disease. Vaccines 

 (100 to 500 millions) should be given every five to seven days : 

 they are contra-indicated when the pyrexia is continuous or 

 remittent. 



VERRUGA. A disease occurring in Peru and other parts of S. 

 America. Two forms have been described ; a chronic granule - 

 matous one and an acute form attended with high fever (Oroya 

 fever or Carrion's disease). The latter is probably an acute 

 disease occurring in a verruga patient. Barton found para- 

 typhoid infection sometimes present. Peculiar little bodies, 

 something like piroplasmata, are present in the red corpuscles 

 (Bartonia, I protozoa). The disease may be conveyed by mos- 

 quitoes. 



Micro -Organisms of the Skin and Mucous 

 Membranes 



Skin. -In the normal clean skin micro-organisms are scattered 

 here and there in cracks of the horny layer and in crevices around 

 hairs and glands, but such skin is not swarming with microbes. 



1 Journ. of Hyg., vol. vii, 1907, p. 115. 



2 Journ. Trop. Med. and Hygiene, February 15, 1913. 



