374 POISONS, CONTAGIONS, MIASMS. 



bination with their substance. The action of sul- 

 phuric, muriatic, and oxalic acids, hydrate of potash, 

 and all those substances which produce the direct 

 destruction of the organs with which they come 

 into contact, may be compared to a piece of iron, 

 which can cause death by inflicting an injury on par- 

 ticular organs, either when heated to redness, or 

 when in the form of a sharp knife. Such substances 

 are not poisons in the limited sense of the word, for 

 their injurious action depends merely upon their 

 condition. 



The action of the proper inorganic poisons is 

 owing, in most cases, to the formation of a chemical 

 compound by the union of the poison with the con- 

 stituents of the organ upon which it acts ; it is 

 owing to an exercise of a chemical affinity more 

 powerful than the vitality of the organ. 



It is well to consider the action of inorganic sub- 

 stances in general, in order to obtain a clear con- 

 ception of the mode of action of those which are 

 poisonous. We find that certain soluble compounds, 

 when presented to different parts of the body, are 

 absorbed by the blood, whence they are again elim- 

 inated by the organs of secretion, either in a changed 

 or in an unchanged state. 



Iodide of potassium, sulpho-cyanuret of potassium, 

 ferro-cyanuret of potassium, chlorate of potash, sili- 

 cate of potash, and all salts with alkaline bases, 

 when administered internally to man and animals in 

 dilute solutions, or applied externally, may be again 

 detected in the blood, sweat, chyle, gall, and splenic 

 veins ; but all of them are finally excreted from the 

 body through the urinary passages. 



Each of these substances, in its transit, produces 

 a peculiar disturbance in the organism, — in other 

 words, they exercise a medicinal action upon it, but 

 they themselves suffer no decomposition. If any of 

 these substances enter into combination with any 

 part of the body, the union cannot be of a perma- 

 nent kind ; for their reappearance in the urine shows 



