ACTIVE AGENTS 189 



position of meat so that aromatic products of putrefaction could not 

 be detected. From this he drew the conclusion that the decomposi- 

 tion of protein substances in the presence of cane sugar, starch, 

 dextrin, glycerin, or lactic acid may not be accompanied by the 

 formation of the characteristic putrefaction products indol, phenol, 

 and oxyacids. Nevertheless, there is a marked quantitative dif- 

 ference in the two processes decay and putrefaction. The former 

 is marked by the volatilization of the organic constituents either 

 protein or non-proteinwhile the non- volatile mineral constituents 

 are left behind in a form largely available. Putrefaction is the rapid 

 and intense decomposition of nitrogenous" (for the most part protein) 

 bodies by certain bacteria, usually with the formation of large 

 quantities of gaseous, ill-smelling products. There may result as 

 intermediate products, basic substances often having highly toxic 

 properties. These substances have been named ptomaines by 

 Brieger. Many of them contain only carbon, hydrogen, and 

 nitrogen, and are ammonia-substitution products. Some of the 

 simpler ones are : 



Methylamin ..... . . ...... (CH 3 )NH 2 



Dimethylamin . . .......... (CH 3 ) 2 NH 



Trimethylamin ............ (CH 3 ) 3 N 



Putrescin ....... . ....... NH 2 (CH 2 )4NH 2 



Cadaverin .............. NH 2 (CH 2 ) 5 NH 2 



They are usually protein-cleavage products, sometimes resulting 

 from the mere removal of carbon dioxid from the carboxyl of the 

 amino-acid. Putrescin may be formed from ornithin thus: 



CH2 CH2 CH2 CH COOH 



| =| + C0 2 



NH 2 NH 2 NH 2 NH 2 



Ornithin Putrescin 



and cadaverin from lysin : 



GHz GHz GHz OH;: CH COOH CH;! CHr- CH? CH 2 CH 2 



I i I I + co 2 



NH 2 NH 2 NH 2 NH 2 



Lysin Cadaverin 



In putrefying mixtures the ptomaines appear on or about the 

 fifth or seventh day after putrefaction sets in, and disappear, by 

 further cleavage, more or less rapidly, yielding less complex nitrog- 

 enous substances that are non-toxic. 



Active Agents. Liebig and the early workers considered these 

 changes to be purely chemical processes. The ferment was to them 

 an extremely alterable organic substance which decomposed, and 

 by decomposing set in motion its own elements. The momentum 

 thus engendered is sufficient to tear to pieces the fermenting sub- 

 stance. This in turn then possesses the power of imparting to other 

 compounds this same property, or, in other words, they considered 



