FIBROUS CONNECTIVE TISSUE. 47 



The second preparation of mucin was made in a somewhat 

 different manner. The fresh tendons, freed as far as possible 

 from foreign tissue, were cut into thin transverse sections, 

 washed with water somewhat, then soaked for thirty-six hours 

 in about four liters of 10 per cent salt solution, with vigorous 

 agitation from time to time, after which the saline solution 

 was decanted and the tissue washed with water until the 

 chloride was entirely removed. The salt solution on dilution 

 with water gave a distinct turbidity indicating the presence of 

 a globulin. The application of heat likewise produced a 

 precipitate, as did also the addition of dilute acetic and 

 hydrochloric acids. It is thus evident that the salt solution 

 removes at the outset quite an appreciable amount of proteid 

 matter, with perhaps some mucin. The moist tissue, pressed 

 as dry as possible, weighed 1700 grams. It was then 

 extracted with 3.4 liters of half-saturated lime-water for forty- 

 eight hours, two such extractions being made. From these 

 extracts the mucin was precipitated by the addition of 

 0.2 per cent hydrochloric acid, the second extract apparently 

 yielding as heavy a precipitate as the first. The combined 

 precipitates were washed repeatedly by decantation with 

 0.2 per cent hydrochloric acid, lastly with water. The mucin 

 was next dissolved in a little 0.5 per cent sodium carbonate, 

 the solution filtered, made nearly neutral by the addition of a 

 little 10 per cent hydrochloric acid, so as to avoid undue 

 dilution, and then precipitated by 0.2 per cent hydrochloric 

 acid. The precipitate was again washed thoroughly with 0.2 

 per cent hydrochloric acid, and lastly with water, until the 

 acid was entirely removed. It was then transferred to 95 

 per cent alcohol, frequently renewed, and finally boiled with 

 alcohol-ether as long as anything could be extracted. Dried 

 over sulphuric acid, the product came out quite white, but not 

 so bulky as the preceding preparation, and weighed a little 

 over fifteen grams an amount equal to about 0.9 per 

 cent of the moist tissue. 



As already stated, mucin is not readily extracted from 

 tendons by lime-water; at least four cubic centimeters of 



