44 A MANUAL OF BACTERIOLOGY 



toxin (C 6 H 15 N0 2 ) is the specific poison of toxic mussels. 

 Such mussels have invariably been subjected to sewage 

 pollution and the poison is probably produced by the 

 action of bacteria derived from sewage. Neurin and 

 muscarin may occur in decomposing flesh and are ex- 

 tremely poisonous. Some of the ptomines produced by 

 putrefaction, being very similar to certain vegetable alka- 

 loids, may assume considerable medico-legal importance. 

 Toxic ptomines may be formed by both pathogenic and 

 non-pathogenic organisms. 



(2) Toxins. These are the soluble poisons elaborated 

 by the bacteria and excreted by the cells into the sur- 

 rounding medium. They are regarded by Martin and 

 others as being allied to the proteoses. Roux and Yersin 

 suggested that the diphtheria poison might be an enzyme, 

 while Brieger and Frankel regard it as albuminous. The 

 toxins are non-basic substances closely related to the 

 proteins and hence have been named tox-albumins, and 

 are considered to be the specific toxic poisons of the 

 pathogenic bacteria. It is difficult or impossible to 

 prepare them in a state of purity and their chemical 

 constitution is therefore unknown, and they are charac- 

 terised by extreme specificity. Such are the poisons of 

 the diphtheria and tetanus bacilli. 



(3) Endotoxins. These are toxic substances elaborated 

 by the bacteria which do not to any extent escape from 

 the cells. They are as specific as the toxins and possess 

 analogous properties (see below). 



(4) Bacterial proteins. These are toxic constituents of 

 the bacterial cells which do not diffuse from the cells, are 

 not specific, and which probably usually play little part 

 in the production of the disease symptoms. 



LITERATURE. 



On Nitrification, see Warington, Journ. Chem. Soc., 1886, et seq. ; 

 Frankland, Cantor Lectures, 1892 ; Nature, 1890, et seq. ; Lohnis 



