446 EXPERIMENTAL PHARMACOLOGY 



then pour a few drop? of hydrogen peroxide into the test 

 tube. "What happens when the peroxide mixes witli the 

 blood ?. Is the color of the blood changed ? Xow draw off 

 another five cubic centimeters of blood and pour two cubic 

 centimeters of cyanide solution into the test tube. Shake 

 up the mixture and then add hydrogen peroxide to the test 

 tube. Do you get any frothing of the mixture? TVhy ? 

 Does the solution remain bright red ? How do you explain 

 this? Save the test tubes and examine each (in one-half 

 or one per cent solution) spectroscopically (if you have a 

 spectroscope) after the animal dies. A tube of normal blood 

 to which a little (one per cent) sodium citrate solution has 

 been added may also be saved for comparing the spectra of 

 the different samples. 



Now pass a catheter into the bladder (if you can) and 

 draw off some urine. If you cannot pass the catheter, open 

 the abdomen, isolate the bladder, and insert a large hypo- 

 dermic needle through the bladder wall and draw off some 

 urine. Test this urine with Fehling's or Haine's solution 

 for sugar. If you get a positive test, how do you explain 

 the cause of the glycosuria I What factors are involved and 

 what is the mechanism of their action? Do you know of 

 any other drugs that have a similar action? Give a large 

 dose of cyanide and as soon as the respiration stops start 

 artificial respiration to see if you can revive the animal. 

 This is often successful when the dose is not too large. Re- 

 covery usually occurs fairly rapidly if the dose is of 

 moderate size. Kill the animal with cyanide. AVhat is the 

 size of the fatal dose? How does this compare with aconi- 

 tine or strychnine ? Discuss in full your observations on the 

 blood-pressure, cardiac inhibition, nutrition, treatment, res- 

 piration and coagulation of the blood. 



It will be instructive to keep the dead animal for a few 

 hours to see if the blood clots in the vessels. The color of 

 the blood should also be noted after a few hours. Is rigor 

 mortis hastened or delayed in its appearance? 



