The Nature of a Chemical

Some things just aren t meant to 0 together. 

The second rule of toxicology helps to explain why some chemicals are easily excreted from the body, while others are not. It also goes to the heart of why different toxic agents affect us in different ways. The second rule was first posed by Ambroise Pare, a sixteenth-century French surgeon, who realized that Poison. .. kills by a certain specific antipathy contrary to our nature. In other words, a chemical s particular action depends on its inherent chemical nature. 

Alan S. Ym (Al, Modem Poisons A Brief Introduction to Contemporary Toxicology, DOI 10.5822/978-1-61091-609 7 2, 2016 Alan S. Kolok. 

For many toxic compounds, particularly the specialists that bind to very specific cell receptor sites, it would stand to reason that the three-dimensional structure of the toxic compound is responsible for its cellular impact. If the toxic compound is a key, then the receptor molecule is a lock, and for many toxic chemicals, differences in the chemical structure of the molecule (analogous to slight differences in the cutouts on the blade of a key) can lead to alterations in its toxicity. Furthermore, if the toxic mechanism by which a compound elicits a biological eflFect is understood, it stands to reason that molecules that share a similar chemical structure may cause similar effects when organisms are exposed to them. The structure-activity relationship, the correlation between the structure of a chemical compound and its biological activity, is the major corollary that can be derived from Fare s writings. 

There are two very useful and elementary ways that the board could initially be divided. The first would be to divide the organic molecules from the inorganic. This would simply segregate those 

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