L891.] 



Oxygen on the Formation of Ptomaines. 



377 



The method chosen by which to gauge the influence of oxygen on 

 pathogenic properties of bacteria was to estimate the quantity of 

 Ikaloidal bodies or " ptomaines " formed in the putrefactive process, 

 scording as oxygen (1) was freely admitted; (2) was present in 

 loderate quantity ; or (3) was withheld altogether. 



For our knowledge of the ptomaines of putrefaction we are chiefly 



idebted to the researches of Brieger. In their order of formation as 



pell as complexity, the most commonly met are choline, C 5 H 15 N0 2 ; 



idaverine, C 5 H U N 2 ; putrescine, C4H 12 N 2 ; trimefhylamine, (CH 3 ) 3 N ; 



limethylamine, (CH 3 ) 2 NH ; and methylamine, (CH 3 )NH 2 . 



The ptomaines most characteristic of the early stages of putre- 



3tion are the diamines, which include, in addition to cadaverine 

 jentamethylenediamine) and putrescine (tetramethylenediamine), 

 ther two isomeric with the former, but of different, as yet unknown, 

 institution neuridine (C 5 H 14 TSr 2 ) and saprine (C 5 H 14 N 2 ). 



With the exception of choline, all these bodies are non-poisonous ; 

 id choline only produces symptoms when given in very large doses. 



In this respect they differ from another group which possess 



arkedly toxic properties, e.g., muscarine (C 5 H 15 N0 3 ), an oxidised 



lerivative of choline, and neurine (C 6 H 13 NO), also obtainable from 



loline artificially by warmiiig with baryta water ; as also two other 



>dies to which Brieger gave the name of mydatoxine (C C H 13 N0 2 ) and 



'/dine, C 8 H U NO. 



While the poisonous bases are oxidised, the harmless bases are 

 an-oxidised, a circumstance which led Brieger to conclude that 

 sygen plays an important part in the formation of poisonous 

 Ikaloids, and that a free access of oxygen favours the formation of 



Dmaines generally.* 



The observations now recorded supply data for judging how far 

 icse conclusions are correct. 



Their chief result is to show that the formation of the ordinary putre- 

 Mve. ptomaines is favoured by the entire absence of oxygen; the 

 tantity formed under such circumstances being several times greater 



in ivhen oxygen is admitted. 



Method of ResearcJi. 



The method employed for the isolation of the ptomaines was that of 

 Jrieger. Equal quantities of extract of meat, obtained by extracting 

 meat with cold water, were allowed to putrefy, for periods 

 iging from 5 to 8 days, under the three following conditions : 

 (1.) Free Supply of Oxygen. The fluid was placed in a large glasa 

 Blinder, open at both ends, kept in continuous rotation round a 

 jrizontal axis. The direction of rotation was alternately from right 



" Weitere TJntersuclmngen iiber Ptomaine." Hirschwald. Berlin, 1885, p. 27. 



2 c 2 



