SUMMARY. 67 



cholera vibrio, pneumococcus, &c., bring about those destructive 

 processes in toto. On the other hand, it is fairly safe to affirm 

 that vigorous extraction, involving the formation of chemical 

 protein preparations, usually changes that sensitive atomic 

 grouping to such an extent that injection is followed by no 

 bactericidal reaction, or only a very faint one, but rather that 

 these albuminous substances produce only the same reactions 

 as every albuminous substance that is foreign to the system 

 i.e., the formation of precipitines 1 which are certainly very 

 closely allied to the agglutinines. Yet it is very probable 

 that, in the case of somewhat more scantily represented 

 examples, such as Koch's tuberculin (q.v.) and Buchner's plas- 

 mines e.g., of the cholera vibrio and tubercle bacillus specific 

 receptors are present, so that these preparations bring about 

 bactericidal immunising processes. 



SUMMARY. 



1. A group of bacteria produces true toxines in the form of 

 free secretions. After extraction of these soluble poisons there 

 remains a residue of pure non-specific bacterial proteins. Type : 

 Diphtheria. 



2. Another large group appears to form only endotoxines : 

 true toxines which are more or less firmly retained by the 

 living cell, so that they are only secreted to a very small 

 extent in an unaltered condition, and possibly not at all outside 

 the body. When the cells die the toxines are partly liberated 

 and partly retained, or are converted into secondary poisonous 

 modifications no longer possessing the characteristics of toxines. 

 Thus, in the case of this group the dead cells cannot be com- 

 pletely freed from other poisons ; we cannot regard the results 

 as being produced by pure protein alone. With this reserva- 

 tion, however, it is possible to detect the activity of proteins. 

 Type : Cholera, typhus, pneumococcus. 



3. A third group possibly forms no true toxines, even within 

 the plasma. The cell plasma contains poisons of another kind, 

 which obscure the effects of the action of the protein. Type : 

 Anthrax, tuberculosis. It is possible that as our knowledge 

 increases groups 2 and 3 may be united. 



4. The pyogenic action of their proteins is common to all 

 bacteria, and depends, in the main, upon their effects as albu- 



1 For further particulars about precipitines see Michaelis and Oppen- 

 heimer, "Immunitat gegen Eiweisstoffe," Engelmanns Arch., 1902, suppl. 

 vol. . 



