Mi POISONS, CONTAGIONS, MIASMS. 



but an organ in the act of formation ; indeed, it is the sum of all 

 the organs which are being formed. The chemical force and the 

 vital principle hold each other in such perfect equilibrium, that 

 every disturbance, however trifling, or from whatever cause it 

 may proceed, effects a change in the blood. This liquid possesses 

 so little of permanence that it cannot be removed from the body 

 without immediately suffering a change, and cannot come in 

 contact with any organ in the body, • without yielding to its 

 attraction. 



The slightest action of a chemical agent upon the blood ex- 

 ercises an injurious influence ; even the momentary contact with 

 the air in the lungs, although effected through the medium of 

 cells and membranes, alters the color and other qualities of the 

 blood. Every chemical action propagates itself through the mass 

 of the blood ; for example, the active chemical condition of the 

 constituents of a body undergoing decomposition, fermentation, 

 putrefaction, or decay, disturbs the equilibrium between the 

 chemical force and the vital principle in the circulating fluid, and 

 overcomes the latter. Numerous modifications in the composition 

 and condition of the compounds produced from the elements of 

 the blood, result from the conflict of the vital force with 

 chemical affinity, in their incessant endeavor to overcome one 

 another. 



All the characters of the phenomena of contagion tend to dis- 

 prove the existence of vitality in contagious matters. They 

 without doubt exercise an influence very similar to some pro- 

 cesses in the living organism ; but the cause of this influence is 

 chemical action, which is capable of being subdued by other 

 chemical actions, by opposed agencies. 



Several of the poisons generated in the body by disease lose all 

 their power when introduced into the stomach, but others are not 

 thus destroyed. 



It is a fact very decisive of their chemical nature and mode 

 of action, that those poisons which are neutral or alkaline, such 

 as the poisonous matter of the contagious fever in cattle (typhus 

 co-ntagiosus ruminantium), or that of the small-pox, lose their 

 whole power of contagion in the stomach ; whilst that of sausa- 



