The Relationship between Chemical Constitution and Taste

Some time ago the author had occasion to prepare a quantity of phenyl thio carbamide, and while placing it in a bottle the dust flew around in the air. Another occupant of the laboratory, Dr. C. R. Noller, complained of the bitter taste of the dust, but the author, who was much closer, observed no taste and so stated. He even tasted some of the crystals and assured Dr. Noller they were tasteless but Dr. Noller was equally certain it was the dust he tasted. He tried some of the crystals and found them extremely bitter. With these two diverse observations as a starting point, a large number of people were investigated and it was established that this peculiarity was not connected with age, race or sex. Men, women, elderly persons, children, negroes, Chinese, Germans and Italians were all shown to have in their ranks both tasters and non-tasters. At first it was thought that this phenomenon was connected with the acidity or alkalinity of the mouth, but experiment soon showed there was no connection whatever. This peculiar phenomenon offered an interesting opportunity for a chemical study of related compounds. Phenyl thio carbamide has the structure 0-NHC-NH2 l11