CHEMICAL BASIS OF THE ANIMAL BODY. 17 



precipitate is more gelatinous than that of the other acid-albumins, and 

 less readily soluble in alkalis (Morner). 



5. Its specific rotatory power when dissolved in dilute hydrochloric 

 acid or sodium carbonate is independent of the concentration and is 

 given as (a) D = 72 3 (Hoppe-Seyler). 



Syntonin has been stated to be capable of reconversion into myosin or some 

 globulin closely resembling it, by solution in lime-water, addition of ammonium 

 chloride to an amount just short of saturation and neutralisation with acetic acid. 

 The neutral fluid thus finally obtained is allowed to fall drop by drop into distilled 

 water from which a fine coagulum gradually separates out consisting of myosin 1 . 

 Hoppe-Seyler states that by similar treatment all forms of acid-albumin may be 

 converted into globulins resembling myosin 2 . 



3. Alkali-albumin. 



If serum- or egg-albumin or washed muscle be treated with dilute 

 alkali instead of with dilute acid, the proteid undergoes a change in 

 many ways similar to that which was brought about by the acid. The 

 alkaline solution, when the change has become complete, is no longer 

 coagulated by heat, the proteid is wholly precipitated on neutralisation, 

 and the precipitate, insoluble in water and in neutral solutions of 

 sodium chloride, is readily soluble in dilute acids or alkalis. 



Alkali-albumin may be prepared by the action not only of dilute 

 alkalis but also of strong caustic alkalis on native albumins as well as 

 on coagulated albumin and other proteids. The jelly produced by the 

 action of caustic potash on white of egg (p. 11) is alkali-albumin; the 

 similar jelly produced by strong acetic acid is acid-albumin. 



In short the general statement may be made that under otherwise 

 similar conditions, if an alkali is employed instead of an acid to act on 

 proteids, alkali-albumin is formed instead of acid-albumin. In the 

 opinion of many authors 3 the precipitates obtained by neutralising 

 the acid or alkaline solutions which arise during the preparation of acid- 

 and alkali-albumin respectively are to be regarded as identically the 

 same. According to this view the neutralisation precipitate is itself 

 neither acid- nor alkali-albumin but becomes either the one or the other 

 by solution in either an acid or alkali, entering at the same time into 

 union with the acid or alkali. 



Danilewsky 4 has utilised the tropaeolins for the purpose of determining the 

 fixation of acids or alkalis by proteids, and on this he has based a classification of 

 these substances. The tropaeolins are soluble in water, the one (tropaeolin 00) 

 yielding a yellow, the other (tropaeolin 000 No 1.) an orange solution. The first is 



1 A. Danilewsky, Zt. f. physiol. Chem. Bd. v. (1881), S. 158. 



2 Hdbch. d. chem. Anal. Ed. v. (1883), S. 281. 



3 Soyka, Pfliiger's Arch. xn. (1876), S. 347. 



4 Centralb.f. d. med. Wiss. 1880, No. 51. 



