INORGANIC POISONS. 363 



liar property, in addition to those already mentioned. When they 

 are present in excess, they dissolve the first formed insoluble 

 compounds, and thus produce an effect quite the reverse of con- 

 traction, namely, a softening of the part of the body on which 

 they have acted. 



Salts of oxide of copper, even when in combination with the 

 most powerful acids, are reduced by many vegetable substances, 

 particularly such as sugar and honey, either into metallic copper, 

 or into the red suboxide, neither of which enters into combina- 

 tion with animal matter. It is well known that sugar has been 

 long employed as the most convenient antidote for pois-ning by 

 copper. 



With respect to some other poisons, namely, hydrocyanic acid, 

 and the organic bases strychnia, brucia, fyc, we are not acquainted 

 with facts calculated to elucidate the nature of their action. It 

 may, however, be presumed with much certainty, thai experi- 

 ments upon their mode of action on different animal su jstances 

 would very quickly lead to the most satisfactory conclusions re- 

 garding the cause of their poisonous effects. 



There is a peculiar class of substances, which are generated 

 during certain processes of decomposition, and which act upon 

 the animal economy as deadly poisons, not on account of their 

 power of entering into combination with it, or by reason of their 

 containing a poisonous material, but solely by virtue of their 

 peculiar condition. 



In order to obtain a clear conception of the mode of action of 

 these bodies, it is necessary to call to mind the cause on which 

 we have shown the phenomena of fermentation, dcay, and 

 putrefaction to depend. 



This cause may be expressed by the following law, Lng since 

 proposed by La Place and Berthollet, although its t*uth with 

 respect to chemical phenomena hag only lately been proved. " A 



MOLECULE SET IN MOTION BY ANY POWER CAN IMPART ITS OWN 

 MOTION TO ANOTHER MOLECULE WITH WHICH IT MAY BE IN 

 CONTACT." 



This is a law of dynamics, the operation of which is manifest 

 in all cases, in which the resistance {force, affiinity, or cohesion) 

 opposed to the motion is not sufficient to overcome it. 



