Page:Popular Science Monthly Volume 83.djvu/554

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N a previous study on "The Discovery and Nature of Alcohol," we have seen that the various alcohols differ among themselves as to their molecular weights and boiling points. These two differences characterizing the alcohols are associated further with a difference in toxicity or poisonous effect. This we shall now consider.

The relation between the molecular weight of a substance and its toxicity was seen as early as 1837 by Black, but it was not until more than a quarter of a century later that Rabuteau was able to generalize this relationship. In his study of the metals he observed that the higher the molecular weight and boiling point, the greater the toxicity. This law experiment has shown often to be in default for the metals. For the alcohols, on the other hand, it has a striking application.

If greater toxicity be associated with a higher molecular weight and boiling point, it would follow that an alcohol such as amyl, with 88 atoms to the molecule and a boiling point of 138° C, would be more poisonous than ethyl alcohol with 46 atoms to the molecule and a boiling point of 78.4° C. Such, in fact, was early shown to be the case. But it may be objected that the difference between the two is extreme. It would be more convincing if two alcohols, such, for example, as ethyl and methyl, closely approximating in molecular weights and boiling points, complied with the law.

To a comparison of these we shall return.

We shall first consider the experimental evidence which has given to us a measure of the exact toxicity of the various alcohols.

Fr. Petit, who was among the first to busy himself with the study of the toxic effects of alcohol, showed that if alcohol is injected into the veins of an animal, a rapid death ensues. Following this simple experiment a considerable period of time elapsed before the subject was again taken up. The next work recorded is that by two Italian physiologists, Lussana and Albertoni.

These investigators, by a series of interesting experiments,