128 BOARD OF AGRICULTURE. 



solution." The affinities of nitrogen have been described as 

 slight, and Liebig long since asserted that " when those sub- 

 stances are examined which are most prone to fermentation and 

 putrefaction, it is found they are all, ivithont exception^ bodies 

 which contain nitrogen." Nitrogenous compounds, coming in 

 contact with water, undergo spontaneous decomposition, and tliis 

 influence of water is said to depend on chemical affinity. We 

 well know how readily meat decomposes in a damp atmosphere, 

 and how long animal products will keep in a rapidly drying 

 medium. The dried-up bodies of men and animals in South 

 America prove this, and butchers are aware that in the winter 

 the weather may be cold, but a damp air will turn the freshest 

 meat sour in a few hours. But I take a piece of meat which has 

 been preserved fresh for months, expose it to moisture in a moist 

 atmosphere or even by immersion, and it resists destruction so 

 long as my preservative agent is not completely washed out. 

 A few drops of carbolic acid on meat will completely prevent 

 decomposition, and it is hard to believe that this acid has simply 

 affected the affinities between nitrogen and water. 



It is easy to prove that its action is of a different nature. 



And here I must state as briefly as circumstances permit, the 

 result of recent investigations, which tend to prove the univer- 

 sal operation of the law announced by William Harvey, " omne 

 vivum, ex ovo.^' The development of infusoria, of microscopic 

 organic forms, bacterium, vibrio, &c., in putrid substances, has 

 long since been recognized. Pouchet of Rouen, in a work on 

 Heterogenesis, or Spontaneovis Generation, has striven to prove 

 that these living, moving particles are due to the development, 

 arrangement, growth and coalescence of molecular matter which 

 produces an opalescence in vegetable or animal infusions. This 

 opalescence is first seen on the surface, and the scum or pellicle 

 thus formed has been termed by him proligerous. Professor 

 Bennett, of Edinburgh, delivered a lecture before the Royal Col- 

 lege of veterinary surgeons of that city on the 17th of last 

 January in support of Pouchet's theories. On the other hand, 

 Pasteur has attempted, and, in the opinion of many, most suc- 

 cessfully, to prove that putrefaction is due to germs deposited 

 on organic matter prone to decomposition, and that the develop- 

 ment of iiifnsoria from pre-existing parents is the cause of 

 clianges, which, as I have striven to show you, Liebig consid- 



