120 CHEMISTRY OF BACTERIA AND THEIR PRODUCTS 



not appearing in the urine 1 but forming formic acid and 

 perhaps glyoxylic acid. Donath 2 found that cholin injected 

 directly into the cortex or under the dura is extremely toxic, 

 causing severe tonic and clonic convulsions, and believes that 

 cholin may be responsible for epileptic convulsions, since he has 

 found that cholin is present in the cerebrospinal fluid of epilep- 

 tics. He corroborated the work of Mott and Halliburton, 

 finding quantities large enough to detect (0.02 to 0.05 per 

 cent.) in the cerebrospinal fluid of patients with dementia 

 paralytica, tabes dorsalis, cerebral syphilis, brain abscess, and 

 other conditions associated with destruction of nervous tissue, 

 but in functional disorders he found it seldom or never. In 

 genuine syphilitic and Jacksonian epilepsy cholin was found in 

 19 of 22 cases. Cholin may be found in normal cerebrospinal 

 fluid, but in extremely minute quantities. When large nerves 

 are cut, cholin appears in the blood, derived from the lecithin of 

 the disintegrating nerve fibers, and is most abundant at the 

 time the Marchi reaction is most prominent in the nerves. 



TOXINS 



Certain bacteria produce soluble poisons by synthetic proc- 

 esses, which poisons are secreted into the surrounding medium 

 and which represent 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 soluble poisons the term toxin has now 

 become limited (for reasons that will be mentioned below), 

 including not only toxins of bacterial origin, but also poisons 

 of similar nature produced by animals (snake venoms, eel serum, 

 etc.) and by plants (ricin, abrin, crotin). The bacteria secreting 

 true toxins are B. diphiherwe, B. tetani, B. pyocyaneus, and 

 _B. botulinus (not including bacteria producing hemolytic sub- 

 stances resembling 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 



neurin constricts the peripheral vessels ; he uses this difference in physiological 

 effect as a means of distinguishing the two substances. Injected into animals, 

 cholin causes a considerable but transient decrease in the number of leucocytes 

 in the blood, followed later by an increase (Werner and Lichtenberg, Deut. 

 med. Woch., 1906 (32), 22). 



1 v. Hoesslin, Hofmeister's Beitr., 1906 (8), 271. 



2 Zeit. f. physiol. Chem., 1903 (39), 526; also see Med. News, 1905 (86), 

 107, for literature and methods of analysis. Full review of subjects of cholin 

 and neurin in these relations by Halliburton, Ergeb. der Physiol., 1904 (4), 



