156 BACTERIOLOGY FOR NURSES 



resulting in a boil or a carbuncle. Endocarditis, septicemia, or 

 pyemia may result from a local abscess through the introduction 

 of the organisms into the lymph or blood stream. Bone tissue 

 seems to be particularly susceptible. The majority of all the 

 attacks of osteomyelitis and periostitis are due to staphylococcic 

 infection. 



Two substances have been isolated from cultures of staphylo- 

 cocci which explain in part their ability to produce disease. One, 

 staphylolysin, acts on the envelope of the red blood cells in such 

 a manner as to dissolve out the hemoglobin, and is consequently 

 responsible in part for the anemia present in such infections. 

 The other substance, leukocidin, has an injurious effect upon 

 leukocytes. Both of these substances resemble the true toxins 

 in that they stimulate the body cells to produce neutralizing 

 antibodies. It is more than probable that these organisms 

 generate other toxic bodies, but as yet nothing definite is known 

 about them. Dead culture of staphylococci when injected sub- 

 cutaneously may produce local abscesses. 



Immunity. Phagocytosis in this case is, without question, 

 the chief factor in immunization ; the amount of opsonin is in- 

 creased, positive chemotaxis occurs, and the phagocytes actively 

 engage in carrying off the invaders. An immune animal serum 

 has been prepared containing antibodies that neutralize staphy- 

 lolysin and leukocidin. Its effect, however, is relatively weak 

 and it is seldom used except to confer passive immunity in cases 

 in which the general vitality is so low as to contraindicate the 

 attempt to produce active immunity by the introduction of 

 vaccine. As a therapeutic measure vaccine treatment has given 

 most satisfactory results, doses commencing with 2 to 20 million 

 organisms gradually increasing to 100 to 1000 million are given. 



Staphylococcus pyogenes albus. This coccus is identical with 

 staphylococcus aureus except that it does not produce a yellow 

 pigment and its pathogenic powers are somewhat feebler. Surface 

 cultures have a milk-white appearance. It has been suggested 

 that it may be a degenerate descendant of aureus, but no one has 

 succeeded as yet in transforming one form into the other. 





