18 HANDBOOK FOR BIO-CHEMICAL LABORATORY. 



chloric acid. The nuclein thus obtained is washed with 

 water and extracted with alcohol and then ether. Dry over 

 sulphuric acid. 



2. Suspend some beer-yeast in water and wash by decanta- 

 tion, and then add it to water containing 5 p.m. HC1. After 

 some time add a slight excess of soda. Filter immediately 

 through a rapid filter and allow to flow into dilute HC1, when 

 a precipitate will fall to the bottom of the flask. Wash by 

 decantation first with dilute hydrochloric acid, then with 

 water, and then with boiling alcohol. Dry in a vacuum. 



Properties. The nucleins are colorless, amorphous, insol- 

 uble or very slightly soluble in water. They are insoluble in 

 alcohol and ether. They are more or less readily soluble in 

 alkalies ; in dilute mineral acids they are insoluble or dissolve 

 with difficulty. On boiling with caustic alkali they decom- 

 pose and alkali phosphates are formed. On fusing with soda 

 and saltpetre they give alkali phosphates also. 



Nucleinic Acids. 



Preparation. Treat 1000 c.c. well-washed yeast with 3250 

 c.c. of a 3$ caustic-soda solution, and allow to digest at the 

 temperature of the room for 5 minutes. Neutralize with hy- 

 drochloric acid, and add an excess of acetic acid. Filter off 

 the precipitated albuminous bodies and measure the filtrate. 

 Now add HC1 to filtrate so that it contains 3-5 p.m., and 

 then add an equal volume alcohol which has previously been 

 acidified to the same extent (3-5 p.m.). The impure nu- 

 cleinic acid thus precipitated is filtered off, dissolved in am- 

 moniacal water, and purified by treating as above, namely, 

 acetic acid, hydrochloric acid, and alcohol. The purified 

 product is dried in desiccator. (Altmann.) 



Properties. Nucleinic acids are white, amorphous, and 

 acid in reaction, readily soluble in ammoniacal or alkaline 

 water, and are not precipitated therefrom by an excess of 



