591.] Oxygen on the Formation of Ptomaines. 379 



the diamines in the observation in which oxygen was excluded. 

 The relation in this instance was reversed, viz., 1 : 3*8, the largest 

 quantity being obtained where oxygen was admitted in moderate 

 quantity. 



(3.) Observations were also made on the effect of lengthening the 

 -duration of the putrefactive process when oxygen was entirely 

 tcluded. The result showed that on the 13th day the diamines 

 jre reduced to one-fourth of the quantity present in a similar 

 lount of fluid, exposed to the same conditions, on the 7th day. 

 (4.) In all cases the bulk of the benzoyl compound obtained was 

 Je up of cadaverine, its melting point varying according to purity 



127'5 C. to 129 C. Putrescine was only present in traces. 

 (5.) The results of the observations on the quality of the bases 

 sent were not so definite. The most definite symptoms of poison- 

 ing were obtained in one instance from the injection of a fluid which 

 putrefied in the absence of oxygen. They included prostration, 

 3reased peristalsis, and diarrhoea, and on another occasion rise of 

 emperature. 



Conclusions. 



Certain conclusions are drawn from the above data, partly of a 

 <cial, partly of a general, character. 



The results are interpreted as tending to support Pasteur's original 

 iws as to the relation of fermentation processes to absence of 

 gen, as against those more recently advanced by Schiitzen- 

 irger, Nageli, Buchner, and others. They show for the putrefactive 

 bacteria at least that a free supply of oxygen prevents fermentation 

 altogether, as judged alike by absence of aromatic products and 

 itomaines, and by presence of ammonia from the very first. 

 They also show that Brieger's view before mentioned as to the 

 essity of the oxygen for the formation of ptomaines must be 

 considerably qualified, the results obtained being entirely opposed 

 such a view. 



As regards the influence of oxygen on the quality of the ptomaines 

 .ed, the conclusion is drawn that the presence or absence of 

 ygen is not the chief factor in determining the formation of 

 poisonous, as distinguished from harmless, ptomaines ; and that other 

 factors, such as duration of putrefactive process and nature of 

 iterial, are likewise incapable of doing so. 



Both the formation and the character of poisonous ptomaines must 

 referred to individual characters of the bacteria present, probably 

 also to the influence of " mixed infection," rather than to the physical 

 ditions under which they act, important as the present observa- 

 >ns prove certain of the latter to be in modifying in a very material 

 the fermentative action of bacteria generally. 



