712 PROTEIDS. [Apr. 



in serum, which he characterises by the name of 'serum-globulin/ and 

 regards fibrinoplastin as a mixture of this body with a portion of fibrin- 

 ferment. "We know for certain (see p. 16) that the whole of the fibrino- 

 plastic precipitate, used to cause the coagulation of a fibrinogenous fluid, 

 does not enter into the composition of the fibrin produced ; we also know 

 that such a precipitate may lose its fibrinoplastic powers without any 

 marked change in its general reactions. It would seem advisable 

 therefore to speak of the deposit produced by carbonic anhydride in 

 dilute serum, or by saturation with sodic chloride in undiluted serum, 

 as globulin, and to distinguish it as fibrinoplastic globulin when it is 

 able to give rise to fibrin. Fibrmogeii similarly might be spoken of as 

 fibrinogenous globulin. The name crystallin rather than globulin 

 might then be given to the substance obtained from the crystal- 

 line lens. 



4. Myosin. 



This is the substance which forms the chief proteid constituent 

 of dead, rigid muscle ; its general properties and mode of preparation 

 have been already described at p. 64. In the moist condition, it forms 

 a gelatinous, elastic, clotted mass ; dried, it is very brittle, slightly 

 transparent and elastic. From its solution in sodic chloride it is pre- 

 cipitated, either by extreme dilution, or by saturation with the solid 

 salt. When precipitated by dilution and submitted to the prolonged 

 action of water myosin loses its property of being soluble in solutions 

 of sodic chloride 1 . The sodic chloride solution, if exposed to a rising 

 temperature, becomes milky at 55 C., and gives a flocculent precipitate 

 at 60 C. This precipitate is however no longer myosin, for it is in- 

 soluble in a 10 p. c. sodic chloride solution, and does not, until after 

 many days' digestion, yield syntonin on treatment with hydrochloric 

 acid ('1 p. c.). It is in fact coagulated proteid (see Class V.). 



Myosin is excessively soluble in dilute acids and alkalis. Advan- 

 tage may be taken of its solubility in the former to extract it from 

 muscles 2 . But if the reagents are at all concentrated, myosin under- 

 goes in the act of solution a radical change, becoming in the one case 

 acid-albumin or syntonin, in the other alkali-albumin (Class II.). 



Like fibrin, it can in some cases decompose hydrogen dioxide, and oxidise guaiacum 

 with formation of a blue colour. 



5. Vitellin. 



As obtained from yolk of egg, of which it is the chief proteid con- 

 stituent, vitellin is a white granular body, insoluble in water, but very 

 soluble in dilute sodic chloride solutions; it surpasses myosin in this 



1 Weyl, Zeitschr.f.physioL Chem.~B&. i. (1878) S. 77. 



2 Danilewsky, Zeitsch. /. pJnjsioL Chem. Bd. v. (1831), S. 158. 



