152 
The filtered residue was dissolved in half-saturated lime water, fil- 
tered through silk and again precipitated with an excess of .2 per cent. 
HCl. This precipitation and solution alternation was continued until the 
eighth precipitation, when this precipitate was filtered by 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 100-105° 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 HCl, 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 ayd 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 ashed and the ash deducted 
from the original weight on the paper. ‘The acid filtrates, usually about 
250ce. in voiume, were poured into about five liters of strong alcohol, al- 
lowed to stand 24-36 hours and filtered on weighed papers. The precipi- 
tates were washed with strong 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. HCl, 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 more complete was the 
precipitation. The weaker the final acidity of the solution was with .2 
per cent. HCl, the less complete the precipitation. The best results were 
obtained with a half-saturated lime water solution saturated with the 
