4.V2 CHEMISTRY OF THE TISSUES. 



solution is precipitated in flocculi. If any salt remains undis- 

 solvcd after the myosin seems fully precipitated, remove it, and 

 then filter the solution. The m3 r osin which contains a large 

 amount of Na( 1 l remains on the filter. In order to free it from 

 This, dry it as well as possible by pressing it between folds of 

 filtering paper ; dissolve it in a little water, and throw the solu- 

 tion into a large beaker full of water, when it will again be pre- 

 cipitated. Let it stand for a day, pour off the clear fluid as well 

 as possible, and then collect the precipitate on a filter. After 

 the greater part of the water has passed through the filter, but 

 while the precipitate is still moist, remove it into a beaker, as 

 it cannot be separated from the filter after it becomes dry. 



frnltiliilHy. Test the solubility of the moist myosin in the 

 following reagents: f 1. Ten per cent. NaCl solution. The 

 myosin will dissolve. Put some sodium chloride in substance 

 into the solution. As it dissolves, and the solution becomes 

 saturated, the myosin will be precipitated. It is soluble in 2. 

 Solution of sodium sulphate or other neutral salt ; 3. Very 

 dilute liquor potassa 1 ; and 4. Very dilute hydrochloric acid. 



Action of Acids and Alkalies. Dilute acid and alkalies dis- 

 solve myosin, as has just been seen. At first it is simply dis- 

 solved, but is very soon converted into acid albumin or alkali 

 albuminate. Divide the solutions of myosin in dilute liquor 

 potassa? and dilute hydrochloric acid just made, into two por- 

 tions, add salt solution immediately to one portion of each, put 

 in a drop of litmus, and neutralize both. No precipitate will 

 fall, for the myosin being unchanged is soluble in the salt solu- 

 tion. Let the other portions stand for ten minutes, and then 

 tivat them in the same way. A precipitate will fall on neutral- 

 izinir them, for the myosin, being now converted into alkali al- 

 buminate and syntonin, is no longer soluble in NaCl solution. 



Coagulation of Myosin. 1. Boil a NaCl solution of myosin ; 

 it will coagulate. 2. Add alcohol to its NaCl solution, and a 

 similar coagulum will form. 



l\li'cct of Drying. Dried myosin is tough and difficult to 

 powder, and almost insoluble in NaCl solution. 



* 62. Extractive Matters in Muscle. The cold 

 watery extract of muscle contains, beside the albuminous mat- 

 ter*, creatine, creatinine, hypoxanthine (sarkin), xanthine, uric 

 acid, inosic acid (apparently not always present), glucose, ino- 

 site, salts of lactic acid, and volatile fatty acids and acid phos- 

 phates of the alkalies. Unless a large quantity of muscle can 

 i, it will be better to use Liebig's extract for the prepara- 

 tion of these substances. Put the watery extract of muscle in 

 a tin kettle; heat it quickly to boiling, so as to coagulate the 

 albumin. Filter it through a linen cloth. Let the filtrate be-. 

 eome quite cool, and add acetate of lead to it as long as a pre- 

 cipitate is formed. Excess of lead must be avoided as much as 



