52 EXPERIMENTAL PHARMACOLOGY 



by padlocks and that the students themselves furnish their 

 own locks. This relieves the instructor of much unneces- 

 sary annoyance. 



Special arrangements will be made for individual experi- 

 ments or for those requiring apparatus which can not be 



Fig. 45. Large bottle for holding stock salt solution. Normal tap water saline 

 (6 or 7 grams of NaCl to the liter) is suitable for most forms of frog or turtle work. 



Locke's solution contains: NaCl, 0.92%; KC1, 0.042%; CaCl 2 , 0.024% (crystals); 

 NaHCO 3 , 0.015%; Dextrose, 0.1%. Ringer's solution contains: NaCl, 0.6%; KC1, 

 0.0075%; CaClo, 0.01% (dried); NaHCO 3 , 0.1%. Tyrode's solution contains: NaCl, 

 0.8%; KC1, 0.02%; CaCU. 0.02% (crystals); NaHCO 3 , 0.1%; MgClo, 0.019c; N T a 2 IiPO 4 , 

 0.005%; glucose, 0.1%. Dissolve the NaHCO :i before adding the CaClo in each case. 



distributed to the class. Much variation will be found in 

 this respect in various schools. Many pieces of apparatus 

 must be made up to fit the experiment or the facilities of the 

 laboratory. (See chapter on shop work, page 470.) 



