POISONOUS BACTERIAL PRODUCTS Ho 



only when these have been uutolyzed.-' With the possibh; exception 

 just mentioued, there is httle evidence that the bacterial enzymes 

 play any important role in infectious diseases. They may be a slight 

 factor in the digestion of tissue and exudates in suppuration, but as 

 compared with the leucocytic enzymes their influence is probably mi- 

 nute; beyond this they have no apparent influence upon their host, 

 and are chiefly concerned in the metabolism of the bacteria. The 

 proteoses and peptones produced by bacterial action and isolated 

 from cultures do not seem to be any more toxic than those produced 

 by pepsin and trypsin, but violent poisons may be liberated from 

 bacteria during autolysis, as Rosenow^^ has shown for the pneumo- 

 coccus and other bacteria; these poisons seem similar to or identical 

 with the so-called anaphjjlatoxin which is supposedly formed by the 

 digestion of bacteria with serum complement, and presumably they 

 are proteoses or polypeptids, but their exact nature is not known. 

 (See Anaphylatoxin, Chap, vii.) 



POISONOUS BACTERIAL PRODUCTS 



Almost without exception all the harm that bacteria do is brought 

 about by means of the chemical substances produced in one vray or 

 another by their metabolic processes. Animal parasites may do harm 

 mechanically, but with the possible exception of the effects of capil- 

 lary emboli (especially with anthrax), bacteria produce all their ef- 

 fects through chemical means. The poisonous chemical substances 

 produced by bacteria are commonly grouped into four classes: 



I. Products of the decomposition of the media upon which the 

 bacteria are growing; among these the best known are the ptomams. 



II. Soluble poisons manufactured by the bacteria, and secreted 

 from the cell into its surrounding media — the true toxins. 



III. Poisons manufactured by the bacteria which do not escape 

 from the normal cell but which are as specific in their poisonous prop- 

 erties as the true toxins; because of their intracellular situation they 

 are called endotoxins. 



IV. Poisonous protein constitutents of the bacterial cell which 

 form part of the cell protoplasm, but which are not soluble, and the 

 poisonous effects of which are not specific and not usually responsible 

 for the disease; these are called bacterial proteins. 



21 Emmerich and Loew (Zeitschr. f. Hyp., 1899 (31), 1), having found that 

 pyocyanase is capable of destroying and digesting other bacteria than pyocy- 

 aneus, suggested that it might be a potent factor in producing artificial immu- 

 nity. Their rather remarkable hypotheses have been much contested, and are 

 of questionable value. (See Petrie, Jour, of Pathol, and Bacteriol., 1903 (8), 

 200; also, Rettger, Jour. Infectious Diseases, 1905 (2), 5G2; Emmerich, Miinch. 

 med. Woch., 1907 (54), 2217). 



" Jour. Infect. Dis., 1912 (10), 113; (11), 94, 235 and 480. 



