THE PROTEIN SUBSTANCES, 23 



The nucleoalbumins are found in organs abounding in cells, but 

 they also occur in secretions and sometimes in other fluids in appa- 

 rent solution as destroyed and altered protoplasm. The nucleo- 

 albumins behave like rather strong acids; they are nearly insoluble 

 in water, but dissolve easily with the aid of a little alkali. Such a 

 solution, neutral or, indeed, a faintly acid one, does not coagulate 

 on boiling. The nucleoalbumins resemble the globulins and the 

 albuminates in solubility and precipitation properties, but differ from 

 them in being hardly soluble in neutral salts. The most important 

 difference between the nucleoalbumins, the globulins, and the albu- 

 minates is that the nucleoalbumins contain phosphorus, and by the 

 action of pepsin hydrochloric acid on nucleoalbumins a phosphor- 

 ized product, nuclein, is split off which, according to LIEBER- 

 MANN, is a combination of albumin with metaphosphoric acid. 

 The nucleoalbumins seem habitually to contain less sulphur than 

 the bodies of the preceding groups. Some iron is found as a con- 

 stant constituent. 



Alkali and Acid Albuminates. By the action of alkalies all 

 native albuminous bodies are converted, with the elimination of 

 nitrogen or by the action of stronger alkali with the emission of 

 sulphur, into a new modification, called alkali albuminate, whose 

 specific rotation is increased at the same time. If caustic alkali in 

 substance or in strong solution be allowed to act on a concentrated 

 albumin solution, such as blood-serum or egg-albumin, the alkali 

 albuminate may be obtained as a solid which dissolves in water on 

 heating forming a jelly, and which is called " LIEBERKUHN'S solid 

 alkali albuminate." By the action of dilute caustic alkali solutions 

 on dilute albumin solutions we have alkali albuminates, formed slowly 

 at the ordinary temperature, but more rapidly on heating. These 

 solutions may be modified by the source of the albumin acted 

 upon, and also by the extent of the action of the alkali, but it is 

 still always the same reaction. 



If albumin is dissolved in an excess of concentrated hydro- 

 chloric acid, or if we digest an albumin solution acidified with 1-2 

 p. m. hydrochloric acid in the warmth, or digest the albumin alone 

 with pepsin hydrochloric acid, we obtain a new modification of 

 albumin which indeed may show somewhat varying properties, 

 but has also certain reactions in common with ordinary albumin. 



