X( IN-SPECIFIC PYOGEXIC COCCI 



195 



for the two first mentioned have been produced, but do not seem 

 to confer immunity. Agglutinins have been demonstrated in 

 normal as well as infected animals; they seem, however, to be of 

 no diagnostic value. The precipitation reaction has likewise 

 been obtained with the bacterial filtrate. Bail has claimed that 

 the production of aggressins accounts for pathogenicity, but his 

 results are inconclusive. Bacteriolysins for Micrococcus aureus 

 are not produced in appreciable quantities, and are probably not 

 of any immunizing value. Opsonins may be demonstrated in 

 both normal and immune blood, and seem to be the most important 

 serum component in determining immunity. 



Immunization. Bacterins and vaccines, both univalent and 

 polyvalent, have been prepared, and have been extensively tested 

 in cases of chronic sup- 

 puration. The results 

 of repeated injections 

 have been encouraging 

 in many cases. A check 

 has been kept on the 

 development of immu- pi 

 nity in man by repeated 

 determinations of the 

 opsonic index. Care is 

 used to eliminate the 

 negative phase as far as 

 possible in making the 

 injections. Autogenic 

 vaccines have proved Fig 8 ^_ 3fiamamu aureus in pus (Frankel 

 even more successful in and Pfeiffer). 



both man and animals. 



The methods of preparation of such a vaccine have already been 

 discussed. It seems altogether likely that the use of bacterins 

 and of autogenic vaccines has found a permanent place in veter- 

 inary treatment. 



Bacteriologic Diagnosis. A mount of pus stained by Gram's 

 method reveals the organism distinctly, if present. Its character- 

 istic morphology will, in general, render its recognition easy. 

 This method has proved to be of particular value in differentiating 



