468 EXPERIMENTAL PHARMACOLOGY 



What is emodin? How is rhubarb excreted? How is the 

 urine influenced by the drug"? What does the addition of 

 alkali to the urine show? Do you know of any other drugs 

 that produce similar results? 



Take a normal tracing and inject one-half cubic centi- 

 meter of lactic acid solution. Wait a little while for the 

 acid to act. Are there any symptoms of embolism? In- 

 ject more acid from time to time and note the action on 

 respiration, blood-pressure and the heart. Do you know 

 of any pathological condition in which similar symptoms 

 may occur? Inject acid until very marked symptoms are 

 produced. Be able to describe these symptoms accurately. 

 Now inject some of the sodium carbonate solution and see 

 how this affects the animal. Continue the injections of 

 carbonate for a while and see if you can get the animal to 

 return to normal. In what pathological conditions might 

 the injection of sodium carbonate solution be of benefit? 



Get the animal into as good condition as possible and 

 then inject into the stomach fifty cubic centimeters of ten 

 per cent nitric acid. (Be sure the anesthesia is satisfac- 

 tory.) 



Examine the color of the urine secreted. Add a few 

 drops of ten per cent NaOH solution and explain any 

 change that may occur. 



Open the abdomen and examine the intestinal loops. 

 What is the condition of each? The normal salt solution 

 should produce no change. The croton oil produces an in- 

 flammatory exudate. This is a different action from that 

 produced by ordinary therapeutic doses of the purgatives, 

 such as castor oil. How do these bodies act in therapeutic 

 doses? The magnesium sulphate should attract more fluid 

 into the intestinal loop by osmosis. ' Do you find this to be 

 the case? What can you say about the ease of absorption 

 of the saline purgatives? How do these bodies act thera- 

 peutically? Does your experiment demonstrate this point? 

 What is the Bayliss-Starling intestinal reflex? 



