71 



death, and have been called by Selmi, their discoverer, Corpse-alkaloids 

 or Ptomaines. Some of these compounds are very poisonous, and 

 Brieger calls them Toxines. To such substances are to be attributed 

 the cases of sickness and death we frequently hear of from eating un- 

 sound meat and meat preparations. All decaying animal and vegetable 

 matter produces substances dangerous to health in various ways, and 

 among the most dangerous and disagreeable of these products are those 

 resulting from the decomposition of the albumenoids. 



But why is it that organic substances when left to themselves are 

 so prone to decomposition ? We have seen that they can exist and 

 pass through vegetable and animal organisms, nourishing and sustaining 

 them, ^'and exercising most beneficent influences in the economy of 

 living oiganised bodies. Why is it that outside of these they behave in 

 an altogether different and most dangerous fashion ? What is it that 

 regulates and controls their chemical affinities for good when they form 

 part and portion of an active living organism ? More than forty years 

 ago Justus Von Liebig put forth a theory according to which the force 

 which controls the affinities is the vital principle. This theory I have 

 never seen any reason to abandon, and I shall try to state it in Liebig's 

 own words. 



" The production of organs, the co-operation of a system of organs, 

 and their power not only to produce their component parts from the 

 food presented to them, but to generate themselves in their original 

 form and with all their properties, are characters belonging exclusively 

 to organic life, and constitute a form of reproduction independent of 

 chemical powers. 



"The chemical forces are subject to the invisible cause by which 

 this form is produced. Of the existence of this cause we are made 

 aware only by the phenomena which it produces." 



"The chemical forces are subordinate to this cause of life just as 

 they are to electricity, heat, mechanical motion and friction." 



"Such an influence, and no other, is exercised by the vital principle 

 over the chemical forces." 



" The vital principle opposes to the continual action of the atmos- 

 phere, moisture and temperature upon the organism, a resistance which 

 is, up to a certain point, invincible. It is by the constant neutralisa- 



