I9I2] ^Alfred P. Lothrop i8i 



The Salt, having an ash content of 2.7-3.3 per cent., is completely 

 soluble in water. A 0.2 per cent. Solution is very much like a rela- 

 tively thick natural saliva. The Solution is faintly alkalin to litmus, 

 gives all the usual protein tests, including the Molisch test for the 

 carbohydrate group, and is precipitated in stringy masses by acetic 

 acid. 



Quantitative determinations of nitrogen and ash in mucin prep- 

 aration III and its sodium salt gave the f ollowing typical results : 



The potassium salt was prepared in the same manner, Fre- 

 quent reprecipitations by alcohol render the salts decreasingly solu- 

 ble in water. 



These products have been made preparatory to experiments on 

 the possible relation of salivary mucin to dental caries, in contin- 

 uance of our studies under the auspices of the Section on Stoma- 

 tology and Research, of the First District Dental Society, State of 

 New York. 



34. A study of some of the more important biochemical 

 tests.^^ C. A. Mathewson. Representative substances from the 

 following groups were studied in their influence on the tests named 

 below: neutral inorganic salts, neutral organic Compounds, acids, 

 acid salts, bases, basic salts, biological mixtures and miscellaneous 

 materials. Over seventy-five substances or products were used in 

 each case. It was found that the ten tests under examination could 

 be arranged in the following sequence according to the percentage 

 of factors causing interference with them: Sudan III, o; xantho- 

 proteic, 4; Hopkins-Cole, 4; Seliwanoff, 5; MoHsch, 6.5; iodine, 

 (for starch) 6.5 ; Fehling-Benedict, 10; biuret, 13; Millon, 22; Bar- 

 foed, 60. 



The acid salts were the most potent interfering substances, the 

 neutral organic Compounds the least potent. Of the salts, ferric 

 chlorid was the most active agent of interference. An extension of 

 the study is in progress. 



''Mathewson: Dissertation, Columbia University, 1912. 



