GENERAL ACTION OF ALCOHOL 133 



EXPERIMENT X. 



Alcohol. (Frog: Central Nervous System, Heart and Vago- 



sympathetic Nerve.) 



1. Solutions of alcohol for injections or administration 

 by stomach should, if possible, be made up from absolute 

 alcohol. For the technic of injecting solutions into the 

 lymph spaces of frogs see Figs. 125 and 126. Make up 

 nine cubic centimeters of alcohol 66 2/3 per cent strong. 

 Into the anterior lymph sac of a frog inject either from a 

 glass injecting pipette (Fig 127) or with a hypodermic 

 syringe (Fig. 126) one cubic centimeter of the alcohol so- 

 lution. Do not injure the frog in any w r ay in holding it, 

 etc. Place the animal in a battery jar on some moist cot- 

 ton and observe its actions closely. Touch it from time 

 to time to observe the condition of the reflexes. Does the 

 animal show any symptoms from the local irritation of 

 the drug at the point of injection? Do these obscure the 

 later systemic effects which come on after absorption of 

 the drug by the circulation? How do the symptoms pro- 

 duced by alcohol compare with those produced by ether or 

 chloroform or nitrous oxide? What organs are affected 

 by alcohol as shown by this experiment? Does the frog 

 become completely narcotized? If so, how long does the 

 condition last? Does the animal recover completely? 

 Place it in a battery jar on moist cotton for several hours 

 to allow of recovery. The beating of the heart can be 

 seen through the chest wall in front. 



2. Pith a frog and dissect out the vagus nerve. Place 

 the electrodes so that the nerve can be stimulated without 

 disturbing the animal and arrange for taking a heart trac- 

 ing. Take two inches of normal tracing and then stimulate 

 the vagus nerve. Do you get a normal inhibition 1 ? (Do 

 not stimulate the nerve too long or too often or you will 

 w^ear it out. You can not then test the action of the drug 



