PRACTICAL APPLICATIONS 375 



known to be developed in the blood, and Eyre's attempts to 

 produce a powerful curative or preventive serum were unsuccessful. 

 There is more evidence pointing to opsonic action in the cure of 

 the disease and the subsequent immunity : the index early in the 

 disease is as a rule low, and it rises during the progress of the 

 case. In some points the immunity reactions of the disease 

 resemble tubercle (slow development of the immunity, frequency 

 of relapses, absence of known bacteriolytic properties in the 

 serum, local toxicity of the cultures), but there is this marked 

 difference, that Malta fever is essentially a septicaemia, the cocci 

 being present in the blood in small or large numbers in practically 

 all cases. 



The agglutinative reaction, first studied by Wright and Smith 

 is of enormous importance in the diagnosis of the disease, and 

 it was Zammit's discovery of clumping powers in the blood of 

 the goat that led to the discovery of the fact that the milk of 

 these animals was frequently infective even when the animal had 

 no signs of disease. Remedial measures based on this phenomenon 

 have been of enormous advantage in checking the disease. 



Various criteria are adopted in the application of the reaction 

 to diagnosis of disease in man. Critien uses a dilution of i : 10, 

 and a time-limit of half an hour, and finds results thus obtained 

 as conclusive as if higher dilutions were used. Bassett-Smith 

 recommends i : 30, with a time-limit of four hours, or twenty- 

 four if the macroscopic method be used. Eyre, however, points 

 out that the blood not infrequently clumps in a high dilution, but 

 not when more concentrated e.g., giving no reaction between 

 i : 10 and i : 100, but clumping strongly at i : 200. It 

 appears, therefore, that a series of dilutions should be made if 

 negative results are obtained with the test adopted as a standard. 

 Agglutination may be manifested in very high dilutions, even as 

 high as i : 500,000. It usually appears about the fifth day. 

 The only other certain method of diagnosis is the isolation of the 

 organism from the blood, usually a fairly easy matter. 



The treatment of the disease by means of vaccines has been 

 studied by Reid, and more recently by Bassett-Smith. The 

 latter recommends a ten-day-old agar culture, emulsified in dis- 

 tilled water, sterilized at 60 C. for an hour, and sufficient carbolic 

 acid added to bring the strength to 0-5 per cent. It is standardized 

 by drying 20 c.c. (of course, before the addition of the carbolic 

 acid), and weighing the solid residue. The results thus obtained 



