I note briefly several interesting comments regarding my recent posts on these two topics. Ethanol. One commenter underscores the futility of seeking the answer to dependence on foreign oil in ethanol by noting that the United States consumes 150 billion gallons of gasoline a year (excluding all other derivatives of oil, including diesel fuel and kerosene). To produce the equivalent energy content in ethanol would, the commenter suggests, require harvesting 600 million acres of corn (versus the current 90 million), covering an area of nearly a million square miles--an area larger than all U.S. farmland. Social-host liability. One commenter argues that social hosts faced with an intoxicated friend who insists on driving have no reasonable recourse. I do not think that is quite true. As another commenter points out, accidents caused by drunk driving are much more frequent at extremely high levels of intoxication, which are manifest to the bartender or host asked to serve the customer or guest a drink. The liability is not for failing to prevent an intoxicated guest from driving, as such, but from continuing to serve liquor to the guest after it is apparent that he is intoxicated. Another commenter reports that he was in an English pub a few years ago that had installed a device consisting of a straw-dispenser, a Breathalyzer, and a series of tiny key safes (miniature versions of the lockers one might find in train stations or post offices). The customer was encouraged (though not required) to put his car key in the safe at the beginning of the evening and at the end get a straw, blow into it, and if he scored less than the legal limit the safe would open and he would get his car key and drive off. Alas, it appears that while some patrons were happy to use the device early in the evening, they became quite belligerently upset with their choice later when they were denied their key. And so the device was abandoned. But there is now discussion in this country of requiring the installation of similar engine-lock devices in all new automobiles. Another commenter reports a custom in China that a host should ply his guests with liquor as a signal of hospitality. When the chief means of transport was a car pulled by a horse or donkey, the custom was harmless, but it is continuing in the age of the automobile, though diminishing in South China, the most economically developed part of the country and hence the part in which the persistence of the custom is most harmful.