126 EMIL VON SKRAMLIK 



chloride, tartaric acid and cane sugar. The anaesthetics are Usted below 

 according to their chemical structure : 



Anaesthesin, Orthoform, Cycloform, Anaestheform, Subcutin, 

 Novocain, Tutocain, Larocain, Pantocain, Stovain, Alypin, 1-Cocain, 

 Psicain old, Psicain new and Tropacocain in 0.30 M solutions, Eucain^^ in 

 0.176 M solution and Holocain, Diocain, Acoin, Percain and Eucupin were 

 used in 0.03 m solutions. The latter substances had too low a solubility to 

 permit 0.30 m solutions to be made. Anaesthesin, Orthoform and Cyclo- 

 form had to be dissolved in 40-50 per cent alcohol. 



The gustatory surface in the mouth was brushed with the anaesthetic 

 solution for 3 min, in the following order : first the tip of the tongue, then 

 the sides, the middle, the bottom and finally the soft palate. 



The thresholds were measured before and 1, 5, 10 and 30 min after the 

 application of the anaesthetic. These measurements were always made in 

 the same order : Sodium chloride, tartaric acid, and cane sugar, leaving 

 quinine to the last, because bitter substances and especially quinine salts 

 are very liable to adhere to the tongue. 



A. The dependence of the anaesthetic action on a number of factors will 

 be presented. These factors are the chemical structure of the anaesthetic 

 and its concentration, the biological substrate, the duration of the applica- 

 tion of the anaesthetic, the time after application, and the subject tasted. 



(a) The action of different anaesthetics is quite different. From the 

 data in Table 1 it is apparent that some substances have a very strong, and 

 others a very weak effect on the gustatory field. To the first mentioned 

 group belong Pantocain, Psicain ne\\\ Subcutin and Anaestheform, and to 

 the latter mainly Tutocain and Novocain. This is most easily seen from the 

 figures in the column labelled bitter, test subject I. Even 10 min after the 

 application of Pantocain the threshold is many thousand times higher than 

 normal while no threshold value at all could be obtained 10 min after 

 Psicain new. Even application of powdered quinine hydrochloride to the 

 tongue gave no taste sensation at all. It only felt like a sandy powder. 

 Tutocain on the other hand showed only a 33-fold threshold increase after 

 1 min, and Novocain a 22-fold increase. 



The findings on the increase in threshold are on the whole duplicated 

 in the other three substrates (salty, sour and sweet), but to a lesser degree. 

 According to their susceptibility to most anaesthetics, the four substrates 

 may be arranged in a sequence : 



bitter > salty > sour > sweet 



It should be definitely pointed out, however, that this is not the same 

 sequence as is obtained by arranging the substrates according to their 

 physiological sensitivity as measured by their threshold to our four gusta- 



