The author, one M. Rosenberg, ran an "oral malodor clinic" in Tel Aviv at the time, which was 1995. The aim of his research -- and a fine aim it is -- was to find out, in a scholarly, clinical, published-in-a-peer-reviewed-research-journal sort of manner, whether there is any conceivable way that human beings can accurately judge the smell of their own breath.

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The dentist had begun to wonder. Day in and day out, patients would come to his clinic, claiming, as he put it, "to be able to smell their own malodor." He set forth their techniques: The tried-if-not-true cupping of the hands over mouth and nose; the breathing beneath the blanket ploy; the smelling of the telephone mouthpiece or the dental floss; and the uncommon -- and exotic -- licking and subsequent sniffing of the wrist.

And so, with help from six dentist pals and financial support from the Tel Aviv University Authority for Applied Research and Development, Rosenberg gathered up 52 Israeli citizens, 43 of whom had claimed to have bad breath, and let them try a few of their tricks. He had them cup their hands over their mouth and nose. He had them lick their wrist (in, for unknown reasons, "a perpendicular fashion"). He also had them try one they hadn't heard of. He had them expectorate into a petri dish that was then closed and allowed to incubate for five minutes at 37 degrees, centigrade, whereupon it was opened -- and here we must pause to acknowledge the deft wording of what must surely stand as the most unsavory task ever asked of a research volunteer -- and "presented for odor assessment."

At the same time, the dentist himself, wearing the mantle of "odor judge," would rate each subject's breath himself. Our man Rosenberg smelled 52 open mouths, glistening wrists, and incubated saliva samples (and, lest we forget, a chicken dung-based fertilizer in an opaque sniff bottle).

What he found confirmed his suspicions. With the exception of the incubated spit technique, there was no significant correlation between the subjects' ratings of their own breath odor and Rosenberg's ratings of it. Assuming for the moment that few of us possess the technical expertise or constitutional wherewithal for incubated saliva sniffings, it would seem there is in fact no simple and accurate way to know if you have bad breath.

Which brings us to our final key word: "psychopathology." Not knowing if one's breath stinks can have hugely peculiar consequences. Not knowing leads to assuming, which, in a handful of instances, leads to a very specialized breed of hypochondria. Rosenberg's references include a paper entitled "Delusional halitosis: Review of the literature and analysis of 32 cases."

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