NATURE OF SUPPURATION 207 



accumulation may be slight. When, however, suppuration is 

 taking place in a very dense fibrous tissue, liquefaction may be 

 incomplete, and a portion of dead tissue or slough may remain 

 in the centre, as is the case in boils. In the case of suppuration 

 in a serous cavity the two chief factors are the progressive 

 leucocytic accumulation and the disappearance of any fibrin 

 which may be present. 



Many experiments have been performed to determine whether 

 suppuration can be produced in the absence of micro-organisms 

 by various chemical substances, such as croton oil, nitrate of 

 silver, turpentine, etc., care, of course, being taken to ensure 

 the absence of bacteria. The general result obtained by inde- 

 pendent observers is that as a rule suppuration does not follow, 

 but that in certain animals and with certain substances it may, 

 the pus being free from bacteria. Buchner showed that sup- 

 puration may be produced by the injection of dead bacteria, e.g., 

 sterilised cultures of bacillus pyocyaneus, etc. The subject has 

 now more a scientific than a practical interest, and the general 

 statement may be made that practically all cases of true sup- 

 puration met with clinically are due to the action of living 

 micro-organisms. 



The term septicaemia is applied to conditions in which the 

 organisms multiply within the blood and give rise to symptoms 

 of general poisoning, without, however, producing abscesses in 

 the organs. The organisms are usually more numerous in the 

 capillaries of internal organs than in the peripheral circulation, 

 but the application of the newer methods of cultivation has 

 shown that they can be detected in the peripheral blood much 

 more frequently than was formerly supposed to be the case. 

 The essential fact in pyaemia, on the other hand, is the occur- 

 rence of multiple abscesses in internal organs and other parts of 

 the bodv^. In most of the cases of typical pyaemia, common in 

 pre-antiseptic days, the starting-point of the disease was a septic 

 wound with bacterial invasion of a vein, leading to thrombosis 

 and secondary embolism. Multiple foci of suppuration may be 

 produced, however, in other ways, as will be described below 

 (p. 220). If the term "pyaemia" be used to embrace all such 

 conditions, their method of production should always be dis- 

 tinguished. 



BACTERIA AS CAUSES OF INFLAMMATION AND SUPPURATION. 



A considerable number of species of bacteria have been found 

 in acute inflammatory and suppurative conditions, and of these 



