BACTERIAL PROTEINS 127 



After extraction the cellular substance is ground, first in porcelain, then in agate 

 mortars, and passed through the finest meshed sieves to remove bits of agar. The 

 person grinding the cellular substance should wear a mask in order to protect him- 

 self against poisoning. Vaughan reports that, despite this precaution, several workers 

 have been acutely poisoned, especially with the typhoid bacillus. Of course, there 

 is no danger of infection, as the bacteria are killed during the treatment. If the 

 finely ground cellular substance, in the form of an impalpable powder, is kept in wide- 

 mouthed bottles in a dark place, it will retain its toxicity for years. This powder 

 constitutes the bacterial protein substance, which may be split up by various means. 

 Vaughan found digestion with 2 per cent, caustic soda in absolute alcohol especially 

 satisfactory for extracting the poisonous group from bacterial or any other protein. 



Nature of Bacterial Proteins. Vaughan and his coworkers regard 

 bacteria as essentially participate, specific proteins. He has not been 

 able to demonstrate the presence of cellulose and carbohydrates; fats 

 and waxes 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 



