Thus, Kussmaul, in 1859, tested twenty-one children with solutions of sugar and of sulphate of quinine. In general the sweet and the bitter caused “the same mimetic facial movements as are observed in adults.” There seemed, however, to be certain individual differences in sensitivity, and occasionally sweet and bitter provoked facial reactions which were not distinguishable. Guezer, in 1873, studied fifty newborn infants by giving them tastes of sugar, quinine, and weak acetic acid. The sugar, as a rule, produced “pleasurable sucking,” the quinine and acid produced “unpleasant ‘bitter’ expression and even nausea movements.” Kroner, in 1882, recorded studies of the taste reactions of his own children at birth. He observed that they reacted immediately after birth to sweet and bitter with the characteristic facial expression of the adult. He was convinced that the sense of taste was at birth the best developed of all the senses. The most elaborate study of this kind yet recorded is that of Peterson and Rainey. These observers report tests of 1,060 newborn infants, varying in nationality, color, sex, and period of gestation. The experiments included tests on all the senses. As taste stimuli for salt, sour, sweet, and bitter they employed solutions of salt, acetic acid, simple syrup, and tincture of gentian. The tests of taste showed “with great regularity mimetic reactions to these stimuli characteristic of adults, grimaces of discomfort, or expressions of content and liking.” “The gustatory nerve not only reacts differently to salt, sweet, bitter, and sour at birth, but the same mimetic reactions are observed in premature infants. This nerve is therefore ready to receive taste impressions some time before the normal period of birth.” ------------------------------------------------------------------------ CHAPTER IV TIME RELATIONS OF TASTE QUALITIES _The Inertia of the Taste Organs_