406 CONSIDERATION OF CARBON COMPOUNDS. 



other solvents. He also showed that these substances resemble vege- 

 table alkaloids in many respects, and assigned to them the name 

 ptomaines, derived from 7rr//a, that which is fallen i. e., a cadaver. 

 Although Selmi did not succeed in isolating any of the ptomaines 

 completely (he experimented with extracts only) his investigations 

 stimulated other scientists, and by the united eiforts of many workers 

 our knowledge of ptomaines has now advanced so far, that general 

 statements can be given in regard to their origin, composition, phys- 

 ical and chemical properties, action upon the animal system, etc. 



Formation of ptomaines. It has been shown in Chapter 39 that 

 albuminous substances under favorable conditions undergo a decom- 

 position termed putrefaction. Presence of moisture, a suitable tem- 

 perature, ' and the action of a ferment are the essential factors in 

 putrefaction. The ferments are living organized beings, termed 

 germs, bacteria, bacilli, microbes, organized ferments, etc. 



It is during the growth, development, and multiplication of these 

 micro-organisms that the decomposition of the albuminous sub- 

 stances into simpler forms of matter takes place. A full explanation 

 of the exact mode of the formation of decomposition-products from 

 organic matter by the action of bacteria has not been furnished yet, 

 but we do know that ptomaines are found among these products. 

 We also know that certain bacteria split up organic molecules in a 

 certain direction, i. e., with the formation of certain products. We 

 also know that while micro-organisms live chiefly in dead organic 

 matter, they also have the power of existing and multiplying in the 

 living organism, causing the decomposition of living tissues, often 

 with the formation of ptomaines. 



General properties of ptomaines. Ptomaines resemble veg- 

 etable alkaloids in all essential properties. Some contain carbon, 

 hydrogen, and nitrogen only, corresponding to the volatile alkaloids, 

 such as coniine and nicotine, while others contain oxygen also, corre- 

 sponding to the fixed alkaloids. 



Ptomaines and alkaloids both have the basic properties and the 

 power to combine with acids to form well-defined salts ; they have in 

 common a number of characteristic reactions, such as the formation of 

 precipitates with the chlorides of platinum, mercury, gold, as also 

 with tannic acid, phospho-molybdic acid, picric acid, etc. ; and both 

 show corresponding solubility and insolubility in the various solvents 

 generally used for the extraction of alkaloids. 



