STUDY OF ANTISTREPTOCOCCIC SERUM. 127 



3. Delayed Phagocytosis or Phagocytic Crisis. 



The phagocytic crisis may be readily studied in the peritoneum 

 of rabbits treated with serum. It occurs suddenly on top of an 

 extracellular and usually abundant development of bacteria; it 

 occurs only in an exudate that has become thick and purulent 

 in appearance; other things being equal, it takes place more rapidly 

 and certainly in rabbits prepared by bouillon than in those with a 

 normal peritoneum at the time of injection. The preparation of 

 the peritoneum allows this crisis to occur more readily owing to the 

 extreme abundance of leucocytes in the exudate. 



The phagocytic crisis may be complete or incomplete and its 

 time of occurrence varies according to the gravity of the case. If 

 the crisis is incomplete or too much delayed the animal simply 

 survives longer than the controls. It frequently occurs after 

 20 hours and even later when incomplete. 



If the number of bacteria developed is too great or the dose of 

 serum too small the animal may die before phagocytosis is com- 

 plete ; under such conditions the free bacteria at the time of death 

 are restricted in number. 



Death may also occur following a partial phagocytosis succeeded 

 by a new growth of new streptococci that, owing to their adaptation, 

 are again able to invade the exudate. 



Such an instance of delayed and partial phagocytosis we may now 

 consider in detail; a rabbit received G c.c. of bouillon intraperiton- 

 eally and was given an injection the next day, also intraperitoneally, 

 of 1 c.c. of a streptococcus culture to which was added 5 c.c. of 

 preventive serum.* In accordance with the appearance of the 

 bacteria and cells the process of infection may be divided into four 

 stages. 



First stage or stage of free development. — Following the injection 

 a very restricted number of bacteria are engulfed by the relatively 

 numerous cells. The growth of the organisms takes place actively. 

 A preparation made 10§ hours after injection shows a complete 

 absence of phagocytosis; the leucocytes are very numerous however. 



* The control received 0.1 of a cubic centimeter of culture and 5 c.c. of normal 

 horse serum and died eleven hours later with the usual findings at autopsy. 



