322 Chittenden and W hitehouse—Metallic 
had been thoroughly freed from salts and soluble albumin by long 
continued extraction with water. The myosin was separated from the 
ammonium chloride solution by dialysis, being obtained in this man- 
ner as a semi-gelatinous mass, readily soluble in salt solutions. In 
order to form compounds with the various metals, it was found best 
to use a solution of myosin in 5 per cent. ammonium chloride, the 
metallic compound when formed being washed with water until the 
washings gave no reaction for chlorine with silver nitrate. The com- 
pounds were then dried, first at 100° C., then at 110° C., until of 
constant weight. Control experiments with the metallic salt and 
ammonium chloride alone, invariably failed to give any precipitate 
whatever. 
No systematic attempt has apparently been made to study any of 
the metallic compounds of myosin; in fact, few statements are to be 
found regarding the existence of such compounds. Danilewsky* 
some time ago, showed that myosin would combine with free mineral 
acids, uniting with them so that with tropzolin 00 no reaction for 
free acid could be obtained. With strong bases, however, according 
to Danilewsky, myosin does not probably combine, and the state- 
ment is further made that a small amount of calcium oxide ordinarily 
exists loosely combined with myosin, which calcium by coagulation 
of the myosin is liberated. Further, Danilewsky found that on 
adding platinum chloride in excess, to a dilute hydrochloric acid 
solution of myosin, a myosin-platinum chloride compound was pre- 
cipitated, which after washing with water and alcohol and then 
drying at 100-105° C., contained 9°46 per cent. of platinum and 7°26 
per cent. of chlorine. With copper, iron and similar salts we have 
not been able to obtain any precipitate in a hydrochloric acid solu- 
tion of myosin. By adding, however, a solution of a metallic salt 
of such a nature that it does not react with ammonium chloride, 
to an ammonium chloride solution of myosin, a precipitate is pro- 
duced, which as our experiments show, is ordinarily a compound of 
myosin with the metal or metallic oxide. This is readily seen 
by adding either zinc sulphate or ferric chloride to such a solution 
of myosin and then washing the precipitates with water, until the 
washings give no reaction for chlorine or for sulphuric acid. On 
now warming the iron precipitate with dilute nitric acid, a solu- 
tion will be obtained, giving a distinct iron reaction but no reaction 
with silver nitrate for chlorine. Similarly on warming the zine pre- 
* Zeitschrift fiir physiologische Chemie, v, p. 160, 
