84 LOCALIZED INFECTIONS OF PUS NATURE 



blood cultures. Another staphylococcus produces a lemon- 

 yellow color. 



These staphylococci are very widely distributed and seem 

 to be almost constantly upon the surfaces of the body, upon 

 skin, in the sebaceous and sweat-gland openings, on the 

 mucous membranes. For this reason they are of great 

 surgical importance and may originate, in a postoperative 

 infection, from the patient, physician, or nurse. Their rather 

 high resistance to disinfection demands great care in surgical 

 technic. The commonest conditions in which these cocci 

 are implicated are pimples, boils, carbuncles, lymph-gland 

 swellings, osteomyelitis, and endocarditis. 



Vaccines and Opsonins. The use of killed bacteria to pro- 

 duce an increased resistance against an existing infection 

 has already been discussed. This method of treatment is 

 particularly suitable for infections with staphylococci. The 

 procedure is about as follows: Cultures are made from the 

 diseased part, grown in large quantities on laboratory media, 

 washed off, suspended in physiological salt solution and 

 heated to a temperature which will kill their disease- 

 producing properties and stop their multiplication, but will 

 not alter their peculiar chemical composition. The number of 

 bacteria are then counted by a special technic and hypodermic 

 injections are made of definite numbers. The size of dose and 

 rate of increase of number injected are controlled by what is 

 called the opsonic index. The opsonins, as will be remem- 

 bered, are substances in the blood which make the bacteria 

 suitable for ingestion by the white cells of the blood or phago- 

 cytes. The opsonic index is the relation of the ability of the 

 patient's white cells to ingest bacteria as compared with a 

 normal person's white cells. This latter is considered 1. 

 If a person is infected with the pus cocci it means that his 

 opsonic index is below 1, and we try to increase it up to or 

 beyond 1. Many different conditions have been found amen- 

 able to this treatment, but furunculosis has responded better 

 than others. 



