PATHOLOGICAL TRANSUDATES, CYSTIC FLUIDS. 69 



and drop in very dilute sulphuric acid (tenth-normal sul- 

 phuric acid) until the color changes to yellow, showing that 

 the fluid has a faintly acid reaction. Heat again to boiling 

 and filter: in the presence of paralbumin the filtrate will be 

 cloudy. 



2. Precipitate the same volume (25 cc.) of the cystic fluid 

 with three times its volume of 95 per cent, alcohol, filter, 

 wash a few times with alcohol, press the precipitate between 

 filter-paper, then shake it thoroughly with a mixture of one 

 volume of hydrochloric acid and three volumes of water, and 

 proceed as with mucin (see page 71). In the presence of 

 pseudomucin we obtain a precipitate of red cuprous oxide- 

 Pseudomucin is not precipitated by acetic acid and is thus 

 distinguished from mucin. 



A complication may arise if glycogen is also present. This 

 m 7 be detected by treating a part of the precipitate, pro- 

 duced by alcohol, with water and saliva and testing for sugar. 

 If glycogen is present, then the entire quantity of the pre- 

 cipitate is to be treated with saliva and the precipitation with 

 alcohol repeated (Hammarsten). 



