120 CHEMISTRY OF BACTERIA AND THEIR PRODUCTS 



seems to be rapidlj^ destroyed in the body, not appearing in the urine^^ 

 but forming formic acid and perhaps glyoxyhc acid. Donath^^ 

 found that choline injected directly into the cortex or under the dura 

 is extremely toxic, causing severe tonic and clonic convulsions, and 

 believes that choline may be responsible for epileptic convulsions. 

 This view has been opposed, and properly so, by Handelsmann-^ and 

 others. The attempt to ascribe importance to choline as a cause of 

 either toxic or therapeutic effect of x-rays seems also to be entitled to 

 but slight consideration.^'* It is probably a factor in the lowering of 

 blood pressure which results from injection of extracts of various tis- 

 sues, in which it is commonly present in minute amounts,^' for very 

 minute amounts of choline will produce a decided fall in blood pres- 

 sure. ^^ 



The Pressor Bases. — By decarboxylation of amino acids, amines are obtained, 

 and some of them, notablj^ those derived from leucine, tyrosine, phem-lalanine and 

 histidine, have a marked effect on non-striated muscle. These are discussed in 

 Chapter xxi. 



Toxins 



Certain bacteria produce soluble poisons by sj^nthetic processes, 

 which poisons are secreted into the surrounding medium and repre- 

 sent the chief poisonous products of the bacteria, being capable of 

 causing most or all of the symptoms attributed to infection by the 

 specific bacteria that have manufactured them. To this class of solu- 

 ble poisons the term toxin has now become limited (for reasons that 

 will be mentioned below), including not only toxins of bacterial ori- 

 gin, but also poisons of similar nature produced by animals (snake 

 venoms, eel serum, etc.) and by plants (ricin, abrin, crotin). The 

 chief bacteria secreting true toxins are B. diphtherice, B. tetani, B. 

 pyoajaneus, and B. botulinus. Dysentery bacilli, the anaerobes of 

 gas gangrene, and perhaps a few other pathogens also secrete a toxin. 

 Pick considers the active constituent of tuberculin to be a true toxin, 

 or closely related thereto. Also the hemoljiic poisons produced by 

 many bacteria seem to be true toxins. It will be seen that the term 

 toxin has been greatly narrowed since the time when all ptomains and 

 other poisonous bacterial products were called toxins, until now it has 

 come to include the specific poisons of but a few of the great group of 

 pathogenic bacteria. 



Chemical Properties of Toxins. — The chemical nature of the 

 toxins is entirely unknown. By various precipitation methods they 



32 V. Iloosslin, Hofmeister's Beitr., 1906 (S), 271. 



^•' Zeit. f. physiol. Chciii., 190:5 (159), 52(5; also see Med. News, 1905 (86), 107, 

 for literature and incthods of analysis. 



^«Sce Schenk, Deut. med. Wocli., 1910 CMt), 1130. 



" Schwarz and Ledercr, I'lliigcr's Arch., 1908 (124), 353; Kinoshita, ibid., 1910 

 (132), 607. 



•'• Mendel cl al. Jour. I'harin. and Exj). Ther., 1912 (3), 648; Hunt and Taveau. 

 liulletin 73, llyg. Lab. U. H. V. U. Service. 



