164 GENERAL PROPERTIES OF LIVING TISSUES 



The globulins, for example, are insoluble in dis- 

 tilled water, but soluble in dilute solutions of 

 sodium chloride. The osmosis of salts into the 

 distilled water in the above experiment first 

 stimulates and then destroys the contractility 

 of the muscle. 



An increase in the saline content of the muscle 

 juice or " plasma " also acts as a stimulus, and, if 

 excessive, may be fatal. 



Strong Saline Solutions. Place a sartorius 

 muscle on a slightly inclined glass plate. Cover 

 the lowest fourth of the muscle with crystals of 

 sodium chloride. 



Irregular contractions will appear. 



Drying. The effect of loss of water is best 

 shown in nerve. 



Let the nerve of a nerve-muscle preparation 

 dry. Note the twitching of the muscle as the 

 water content diminishes. Test the irritability 

 of the nerve from time to time. with induction 

 currents. It will first increase, then disappear 

 as the nerve dries. 



Wet the nerve with 0.6 per cent sodium 

 chloride solution. 



The irritability will reappear. 



To keep muscles and nerves in good condition 

 for experimentation, it is necessary to moisten 

 them with a solution containing the inorganic 

 salts most abundant in the tissue-liquids in the 



