356 INFECTIVE PROCESSES IN THE PERITONEUM 



These only come into action later. In the case of a mild infection 

 the whole process of cure may occur without their appearance, and 

 they are only of importance in so far as they are the cause of the 

 subsequent immunity. 



Let us now turn to the sequence of events in the peritoneum in 

 these animals in which explosive bacteriolysis does not occur, or 

 only to a small extent, in that region. Here some phagocytosis is 

 found to take place in the cells lying free in the peritoneal fluid, 

 (the changes in which have been noted previously), but the greater 

 part of the process and this is significant in view of the theories 

 which we have adopted with regard to the liberation of comple- 

 ment-opsonin during the process of coagulation takes place in 

 the masses of fibrin found on the omentum. At first the bacilli lie 

 free in this deposit, often lying more or less parallel ; but in a 

 short time vast numbers are taken up by the macrophages, and 

 very few free organisms may be seen in an hour or two after the 

 injection. Then one of two series of phenomena may occur. The 

 animal may recover ; and in this case the bacilli which are con- 

 tained in the macrophages become pale and granular, and soon 

 disappear altogether, and the fibrin becomes infiltrated and eroded 

 by polynuclear leucocytes. Or the animal may die ; and in this 

 case the bacilli, both those which have been ingested and those 

 which have not, commence to grow rapidly, and the organisms, 

 after diminishing in numbers for a few hours, proliferate so quickly 

 that the animal dies in some twenty-four hours. In these cases 

 the bacilli which have been ingested are not destroyed, and retain 

 their normal appearance and staining reactions throughout. 

 Here it is obvious that the first line of defence, the rapid initial 

 phagocytosis, has been unsuccessful, and that the secondary 

 reserve forces have not had time to come into action. It is 

 specially pointed out by Buxton and Torrey that in these cases the 

 invasion of the fibrin by the polynuclear leucocytes does not occur, 

 a fact strongly confirmatory of the view that it is these cells that 

 give rise to the opsonin or complement, the deficiency in which 

 brings about the lethal issue. 



Here we must conclude a short and altogether inadequate con- 

 sideration of a subject of the highest importance. Much more 

 might be written on the subject, but the very fact that the 

 phenomena do not lend themselves to a brief discussion only 

 shows how very imperfect is our present knowledge of the events 

 which actually take place in the juices and tissues during the 



