NITROGENOUS ORGANIC CELL-CONSTITUENTS. 101 



indicating that, in all probability, the boiling has served to convert the 

 acid albumen into an alkali albumen. Acid albumen shows all the 

 reactions of proteids already described. It may be separated from 

 liquids in which it is dissolved by boiling with hydrated oxide of lead. 



2. Alkali Albumen. — If any native albumen in solution is subjected 

 to the action of a dilute alkali, such as sodium or potassium hydrate, it 

 will undergo changes somewhat similar to those produced by the action 

 of an acid. Alkali albumens, or alkali albuminates, may, therefore, be 

 described as albuminous bodies which are insoluble in water or sodium 

 chloride, but readily soluble in dilute acids or alkalies. Their solutions 

 are not changed by heat. When neutralized they are precipitated from 

 their solutions, the precipitate being soluble in excess of acid, unless 

 alkaline phosphates are present ; an excess of acid is then required to 

 produce precipitation. In this conversion heat facilitates the process, 

 and, as in the case of formation of acid albumen, the conversion is a 

 gradual one. When alkali albumen is precipitated from its solution in 

 alkalies by neutralization with an acid, if an excess of acid be added it 

 is again rapidly dissolved,. through its conversion into acid albumen or 

 syntonin. This conversion of alkali albumen into acid albumen is more 

 readily accomplished when the alkali albumen has been freshly precipi- 

 tated. If some time has been allowed to elapse after the precipitation 

 by neutralization, it will still be converted into syntonin by" the action 

 of an acid, but not so readily as when freshly precipitated, unless sub- 

 jected to heat (about 60° C): If alkaline phosphates are present in the 

 solution the alkali albumen is not precipitated on neutralization, but 

 enough acid must be added to convert the basic phosphate into 

 acid phosphate, and, when this is accomplished, the slightest addition 

 of an acid, even of C0 2 , will then be sufficient to precipitate alkali 

 albumen. 



Alkali albuminate ma}' exist either in the form of solution or as a 

 solid. If undiluted white of egg is stirred up with a concentrated solu- 

 tion of caustic potash, or with undissolved caustic potassium hydrate, 

 it will gradually be converted into a stiff' jelly. If this jelly is washed 

 with water so as to remove the excess of alkali, it may be dissolved 

 in warm water, and will then behave like alkali albumen obtained by the 

 action of alkalies on albuminous solutions. If, before solution in water, 

 the solid alkali albuminate has been washed until most of the alkali has 

 been removed, passing a stream of carbon dioxide through the solution 

 will be sufficient to cause precipitation. 



If some pieces of solid alkali albuminate are placed in an acid just 

 strong enough to show an acid reaction after the introduction of the 

 albuminate, the latter will become milky-white, shrivel up, and form an 

 elastic mass, the so-called pseudo-fibrin, which will swell up in dilute 



