500 MALTA FEVER 



immunised against the plague bacillus. It is to be Doted, however, that 

 in elinieal oases the reaction is not invariably present, the potency of 

 the serum is not of high order, and the carrying out of the test is 

 complicated by the natural tendency of the bacilli to cohere in clumps. 

 For the last reason the macroscopic (sedimentation) method is to be 

 preferred to the microscopic (p. 116). A suspension of plague bacilli is 

 made by breaking up a young agar culture in - 75 per cent, sodium 

 chloride solution ; the larger flocculi of growth are allowed to settle, and 

 the fine, supernatant emulsion is employed in the usual way. According 

 to the results of the German Plague Commission and the observations of 

 Cairns, made during the Glasgow epidemic, it may be said that the 

 reaction is best obtained with dilutions of the serum of from 1 : 10 to 

 1 : 50. Cairns found that the date of its appearance is about a week 

 after the onset of illness, and that it usually increases till about the end 

 of the sixth week, thereafter fading off. It is most marked in severe 

 cases characterised by an early and favourable crisis, less marked in 

 severe cases ultimately proving fatal, whilst in very mild cases it is 

 feeble or may be absent. The method, if carefully applied, may be of 

 service under certain conditions ; but it will be seen that its use as a 

 means of diagnosis is restricted. 



Methods of Diagnosis. — Where a bubo is present a little of the juice 

 may be obtained by plunging a sterile hypodermic needle into the 

 swelling. The fluid is then to be examined microscopically, and cultures 

 on agar or blood serum should be made by the successive stroke method. 

 The cultural and morphological characters are then to be investigated, 

 the most important being the involution forms on salt agar and the 

 stalactite growth in bouillon, though the latter may not always be 

 obtained with the plague bacillus : the pathogenic properties should also 

 be studied, the guinea-pig being on the whole most suitable for subcu- 

 taneous inoculation. In many cases a diagnosis may be made by micro- 

 scopic examination alone, as in no known condition other than plague do 

 bacilli with the morphological characters of the plague bacillus occur in 

 large numbers in the lymphatic glands. The organism may be obtained 

 in culture from the blood in a considerable proportion of cases by with- 

 drawing a few cubic centimetres and proceeding in the usual manner. On 

 the occurrence of the first suspected case, every care to exclude possibility 

 of doubt should be used before a positive opinion is given. 



In a case of suspected plague pneumonia, in addition to microscopic 

 examination of the sputum, the above cultural methods along with 

 animal inoculation with the sputum should be carried out ; subcutaneous 

 injection in the guinea-pig and smearing the nasal mucous membrane of 

 the rat may be recommended. Here a positive diagnosis should not be 

 attempted by microscopic examination alone, especially in a plague- free 

 district, as bacilli morphologically resembling the plague organism may 

 occur in the sputum in other conditions. 



Malta Fever. 



Synonyms — Mediterranean Fever : Sock Fever of Gibraltar : 

 Neapolitan Fever, etc. 



This disease is of common occurrence along the shores of the 

 Mediterranean and in its islands. Since its bacteriology has 



