152 



The filtered residue \v;is dissolved in half-saturated lime water, fil- 

 tered through silk and again precipitated with an excess of .2 per cent. 

 HO. This precipitation and solution alternation was continued until the 

 eighth precipitation, when this precipitate was filtered hy decantation 

 and the residue was thoroughly dried by standing with absolute alcohol. 

 The powdery white precipitate was carefully filtered and pulverized, then 

 further dried at 100-10;j o C. for several hours. The bottled sample so ob- 

 tained was used in this set of experiments. 



In the study of the complete precipitability of tendon-mucoid by means 

 of dilute HC1, a definite amount (2 grams) of the dried sample was 

 weighed and dissolved in a mortar with the least quantity of half-satu- 

 rated lime water necessary, about 300cc. The solution was then filtered 

 through silk and by means of a pipette, equal portions of the filtrate were 

 removed to respective beakers and were precipitated by varying amounts 

 of acid. This phase of the acid precipitation was subdivided into a study 

 of the effect of dilution of the mucoid and the effect of the use of varying 

 amounts of acid. In each case duplicate checks were carried along on the 

 amount of actual mucoid present and precipitable under the most favorable 

 conditions. In every instance the mucoid precipitated by the acid was 

 filtered on> weighed papers, dried at 105° C. for several hours and weighed 

 on the paper. The paper and mucoid were then ashe,d and the ash deducted 

 from the original weight on the paper. The acid filtrates, usually about 

 250cc. in volume, ivere poured into about five liters of strong alcohol, al- 

 lowed to stand 24-3G hours aud filtered on weighed papers. The precipi- 

 tates were washed with stronsr alcohol, dried and weighed ; the precipitates 

 and papers were burned respectively, and the ash, ranging from a few 

 tenths of a milligram to a hundred milligrams, was deducted in order to 

 get a value for ash-free mucoid material. 



As results of an extended, investigation of the deportment of mucoid 

 in a half-saturated lime water solution, with .2 per cent. HC1, it was found 

 that not all the mucoid was precipitated under the best conditions. There 

 was always 10 to 20 per cent, of the mucoid precipitated by the strong 

 alcohol treatment and part, perhaps 8 to 10 per cent, of the original mucoid, 

 was not precipitated by the acid nor alcohol treatment. It was found that 

 the more concentrated the solution of mucoid, the rnore complete was the 

 precipitation. The weaker the final acidity of the solution was with .2 

 per cent. HC1, the less complete the precipitation. The best results were 

 obtained with a half-saturated lime water solution saturated with the 



