VII. — The Nature and Chemical Composition of the Myosin 

 OF Muscle Tissue. By R. H. Chittenden and G. Wyckoff 

 Cummins, Ph.D. 



In spite of the interest attached to this peculiar proteid substance, 

 little attention has been directed to its chemical nature since the 

 time of its discovery by Kiihne.* In fact, Danilewskyf is the only 

 investigator who appears to have studied its chemical relations to 

 any extent, and so far as we are aware no attempt has ever been 

 made to ascertain its chemical composition. With this fact in mind, 

 it has been the main object of the present investigation to study the 

 chemical composition of pure myosin, and to determine the diffei'- 

 ences that may exist in the chemical nature, or in the properties, of 

 myosin prepared from various animal sources. Unfortunately, our 

 work was completed before Halliburton's]; recent paper on muscle- 

 plasma was published, otherwise we should have attempted to verify 

 some of his interesting discoveries i-egarding the muscle clot, and 

 possibly have modified somewhat the character of our work. 



The researches of Kiihne, IIoppe-Seyler,§ Weyl,|| and Danilewsky 

 have shown that myosin, both from the animal and vegetable king- 

 doms, is a globulin body, soluble in dilute sodium and ammonium 

 chloride solutions, as well as in sulphate of magnesia and sulphates 

 of the alkalies, and precipitable therefrom either by the addition of 

 salt in substance or by dilution with much water. As stated by 

 Danilewsky, myosin is most advantageously extracted from muscle 

 tissue by ammonium chloride, in solutions of from 7-20 per cent. 

 We have, likewise, found this to be the case by comparative tests, 

 and have, therefore, in all of our preparations of myosin for analysis, 

 used ammonium chloride as the extractive, preferably of 15 percent, 

 strength. For separation of myosin from the ammonium chloride 



* Kiihne, Protoplasma, Leipzig, 18G4. Also Lehrbuch der physiologische Chemie. 



\ Myosin, seine Darstellung, Eigenschaften, Umwancllimg in Sjmtonin und Riickbil- 

 dung aus demselben. Zeitschrift fiir physiologische chemie. Band v, p. 158. 



:]: Journal of Physiology, vol. viii, p. 133. 



§ Handbuch der Chem. Analyse, 4 Auflage, p. 236. 



H Beitrage zur kenntniss thierischei* und pflanzlicher eiweisskorper, Zeitschrift fiir 

 physiologische Chemie, Band i, p. 72. 



