BACTERIAL PROTEINS 129 



and waves that may be present are somewhat secondary and less essen- 

 tial constituents or stored food material. The sum total of the work of 

 these observers would indicate that the greater part of bacteria are made 

 up of true proteins, especially nucleoproteins or glyconucleoproteins, 

 and although they may be simple in structure, they are chemically 

 complex quite as much so as many of the tissues of the higher plants 

 and animals. 



When bacterial cellular substances are split up with mineral acids 

 or alkalis they yield ammonia, mono-amino- and diamino-nitrogen, one 

 or more carbohydrate groups, and humin substances. These protein 

 substances are the same as those obtained by the hydrolysis of vegetable 

 and animal proteins. 



By digestion with dilute acids or alkalis, especially the latter, in the 

 form of a 2 per cent, solution of sodium hydroxid in absolute alcohol, a 

 soluble split product is obtained that resembles in some respects the 

 protamins, although they do not all give a satisfactory biuret reaction. 

 This product is highly toxic, but shows no specificity in its action, being 

 the same whether derived from pathogenic or from non-pathogenic bac- 

 teria, or from egg albumin or other protein substance. All that is defi- 

 nitely known regarding it is that it is toxic, protein in nature, but 

 simpler in structure than the complex proteins of the bacterial cells 

 themselves. 



This soluble toxic portion as obtained in vitro is regarded by Vaughan 

 as the main factor in the production of the general symptoms of infection, 

 the special and distinctive lesions being due to the location of the in- 

 fection. During the infective process the body-cells produce an anti- 

 ferment which, when it reaches a certain concentration or power, begins 

 to split the protein of the microorganism and new bacterial tissue, with 

 the liberation of this toxic moiety, in a manner similar to the splitting 

 observed in vitro by dilute alkalis or acids. 



The insoluble and non-poisonous portion of the cellular proteins 

 shows most of the color reactions for proteins, and contains all the car- 

 bohydrate of the unsplit molecule and most of the phosphorus. 



Action of Bacterial Proteins. The effects produced by bacterial 

 proteins are not specific; the protein substance of non-pathogenic 

 bacteria and, indeed, many proteins derived from vegetable and animal 

 sources, have equally marked pyogenic properties. All foreign proteins 

 introduced into the circulation of animals are more or less toxic, and the 

 toxic effects of all bacterial proteins are, in general, quite similar and 



non-specific. 

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