SALIVA. 



417 



soluble in ether, alcohol, and essential oils, 

 but more sparingly soluble in water. It pos- 

 sesses the odour of saliva, and is precipitated by 

 diacetate of lead, nitrate of silver, and slightly 

 by acetate and nitrate of lead, and by tincture 

 of galls ; neither bichloride of mercury nor the 

 strong acids precipitate it. The latter de- 

 crease its solubility, and heighten its odour, 

 while alkalies render it more soluble, and 

 give it the odour of mucus. Ptyalin, when 

 pure, may be kept a length of time, at a mo- 

 derate temperature, without undergoing de- 

 composition." 



According to Dr. Wright, saliva possesses 

 the property of absorbing oxygen gas, and 

 he states that he has known as much as 2*25 

 times the bulk of the saliva to be taken up. 

 This quality varies, however, in different spe- 

 cimens; in Dr. Wright's opinion, according 

 to the quantity of carbonic acid gas con- 

 tained in the secretion. 



He states he has succeeded in obtaining 

 oxygen from saliva by applying heat, and 

 considers its presence of great value in as- 

 sisting the action of the secretion during the 

 process of digestion, inasmuch as he found 

 that, after exposing saliva to oxygen, so as to 

 enable it to absorb the gas freely, he was en- 

 abled to convert, by its use, a much greater 

 quantity of starch into sugar and gum (an 

 action of which I shall hereafter treat), than 

 by using saliva which had not been exposed 

 to oxygen. 



Dr. Wright's analysis of saliva is as follows : 



Water 988' 1 



Ptyalin - - - - -1*8 

 Fatty* acid ... -5 



Chlorides of potassium and sodium I '4 

 Albumen combined with soda - '9 

 Phosphate of lime '6 



Albuminate of soda '8 



Lactates of potash and soda - ? 

 Sulphocyanide of potassium - '9 



Soda ^ -5 



Mucus, with some ptyalin - - 2*6 



L'Heritier made analyses of saliva as ob- 

 tained from healthy persons, and gives the 

 following as a mean of ten observations on 

 adults : 



Water - - 986*5 



Organic matter - - 12'6 

 Inorganic matter '9 



Of the organic matters 2*5 parts consisted 

 of salivary matter, or ptyalin (probably not 

 the ptyalin of Dr. Wright, but that described 

 by Berzelius and Simon). 



Saliva of Children. Observations by L'He- 

 ritier on the saliva of children showed the 

 quantity of water to be greater in early life. 

 He gives the following as the mean of four 

 analyses : 



Water ... 995-0 



Organic matter - - 3'5 

 Inorganic matter %5 



The ptyalin contained in the organic matter 

 amounted to only 1*1. 



VOL. IV. 



Male and Female Saliva. L'Heritier states 

 that he could detect no difference between 

 the saliva of men and women. 



Enderlin has made several analyses of the 

 ashes obtained from different specimens of 

 saliva, and has found them to be similarly con- 

 stituted. 



In his opinion, the tribasic phosphate of 

 soda it contains is valuable as a solvent of the 

 protein compounds. He denies the existence 

 of alkaline lactates, not only because the ashes 

 of saliva yielded no carbonate in his experi- 

 ments, but because he failed in detecting them 

 by direct observation before incineration. His 

 analyses of the ashes of saliva, as obtained 

 from a large quantity of the secretion from dif- 

 ferent persons, yielded the following result : 



Tribasic phosphate of soda - - 28*122 



Chlorides of potassium and sodium - 61*930 



Sulphate of soda - 2*315 

 Phosphate of lime ~| 



Phosphate of magnesia [- - - 5*509 

 Peroxide of iron 



The existence of the sulphocyanide of potas- 

 sium in the saliva is a matter of importance, 

 and some difference of opinion is observed 

 among chemists on the subject. The dis- 

 covery was originally announced by Trevi- 

 ranus, who noticed that saliva, when mixed 

 with a neutral solution of the peroxide of 

 iron, produced a dark red colour. This he 

 regarded as produced by an acid, to which the 

 name of "acid of the blood" had been given 

 by Winterl, and which was afterwards known 

 as the sulphuretted chyazic acid of Porrett. 

 Tiedemann and Gmelin examined into this 

 question, and found that the reaction de- 

 scribed by Treviranus really occurred on 

 adding persalts of iron to saliva, and made 

 experiments to discover whether the colour- 

 ation was produced by a sulphocyanide. 

 After lengthened observation, these physio- 

 logists arrived at the conclusion that such 

 was the case, and procured other reactions 

 besides such as were obtained by testing with 

 iron, which satisfied them of the presence of 

 sulphocyanogen. 



Dr. Wright mentions sulphocyanide of po- 

 tassium in his analysis of saliva, and states 

 that its quantity is always increased by locally 

 stimulating the salivary glands, as by smoking 

 or chewing sialogogues. The internal use of 

 prussic acid or salts containing cyanogen in- 

 creases its quantity. It is also greatly in- 

 creased by the use of sulphur. Dr. W. says 

 the presence of this salt is best detected in 

 the alcoholic extract obtained from dried 

 saliva. The sulphocyanide of potassium con- 

 stitutes, according to his observations, from 

 051 to 0-098 of the secretion. Kuehn tried 

 to detect the presence of a sulphocyanide in 

 saliva, but failed. He could not prove the 

 presence of sulphur either by the processes of 

 Gmelin or Ure. Miiller, also, was not satis- 

 fied by his observations that the red colour 

 produced in iron resulted from the presence 

 of sulphocyanogen. 



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