MIXED SALIVA. 455 



or it gradually becomes cloudy. Its reaction is generally alkaline to 

 litmus. The degree of alkalinity varies considerably not only in dif- 

 ferent individuals but also in the same individual during different parts 

 of the day, so that it is difficult to state the average alkalinity. Accord- 

 ing to CHITTENDEN and ELY it corresponds to the alkalinity of 0.8 p. m. 

 Na2COs solution, or to 0.2 p. m. solution according to COHN. According 

 to FOA the actual alkalinity (OH-ion concentration) is always consider- 

 ably less than that found by titration, and the reaction determined 

 electrometrically is very nearly neutral. The reaction may also be acid, 

 as found to be the case by STICKER some time after a meal, but this is 

 not true, at least for all individuals. The specific gravity varies between 

 1.002 and 1.008, and the quantity of solids between 5 and 10 p. m. 

 According to CoHN, 1 A= 0.20 on an average, and the amount of NaCl 

 is 1.6 p. m. The solids, irrespective of the form-constituents men- 

 tioned, consist of protein, murin, oxidases, 2 two enzymes, ptyalin and 

 maltase, as well as a dipeptid and a tripeptid splitting enzyme 3 and 

 mineral bodies. It is also claimed that urea is a normal constituent of 

 the saliva. The mineral bodies are alkali chlorides, bicarbonates of 

 the alkalies and calcium, phosphates, and traces of sulphates, nitrites, 

 ammonia, and sulphocyanides, which latter average about 0.1 p. m. 

 (MuNK and others). Smaller quantities, 0.03-0.04 p. m., are found in 

 the saliva of non-smokers (SCHNEIDER and KRUGER), while from ordin- 

 ary smokers the quantity of sulphocyanides may rise to 0.2 p. m. 

 (FLECKSEDER 4 ) . 



Sulphocyanides, which, although not constant, occur in the saliva of 

 man and certain animals, may be easily detected by acidifying the saliva 

 with hydrochloric acid and treating with a very dilute solution of ferric 

 chloride. As control, especially in the presence of very small quantities, 

 it is best to compare the test with another test-tube containing an equal 

 amount of acidulated water and ferric chloride. Other methods have 

 been suggested by GSCHEIDLEN, SOLERA, and GANASSINI. The quantita- 

 tive estimation can be done according to MUNK'S 5 method. 



1 Chittenden and Ely, Amer. Chem. Journ., 4, 1883; Chittenden and Richards, 

 Amer. Journ. of Physiol., 1; Foa, Compt. rend. soc. biol., 58; Sticker, cited from 

 Centralbl. f. Physiol., 3, 237; Cohn, Deutsch. med. Wochenschr., 1900. 



2 Bogdanow-Beresowski, cited from Biochem. Centralbl., 2, 653; Herlitzka, Maly's 

 Jahresber., 40; ^panjer-Herford, Virchow's Arch., 205. 



'Warfield, Johns Hopkins Hosp. Bull. 22 (1911); Koelker, Zeitschr. f. physiol. 

 Chem., 76, (1911). 



4 Munk, Virchow's Arch., 69; Schneider, Amer. Journ. of Physiol., 5; Kriiger, 

 Zeitschr. T. Biologic, 37; Fleckseder, Centralbl. f. innere Med., 1905. In regard to 

 the variation in the amount of various constituents in saliva see Fleckseder, 1. c., and 

 Tezner, Arch, internat. de Physiol., 2. 



5 Gscheidlen, Maly's Jahresber., 4; Solera, see ibid., 7 and 8; Munk, Virchow's 

 Arch., 69; Ganassini, Biochem. Centralbl., 2, p. 361. 



