466 EXPERIMENTAL PHARMACOLOGY 



is injected.) Clip the hair and shave a small area on the 

 animal's side. Wet a pledget of cotton with twenty per 

 cent sodium (or potassium) hydrate solution and lay the 

 cotton on the prepared area. Let it stay for some time 

 and then examine the condition of the skin on the area. 

 What conclusions can you draw? Wet another pledget of 

 cotton with dilute acetic acid and place this on the area. 

 See if this in any way changes the character of the results 

 produced by the alkali. What conclusions can you draw? 

 After death remove the stomach and the upper end of 

 the small intestine (cut between double ligatures) and open 

 the stomach (over a sink). What changes do you find in 

 the stomach walls? Would you recognize such a stomach 

 at autopsy in a case of poisoning ? Did the alkali pass into 

 the small intestine? If so how far down did it go? Did 

 the vanadium have anything to do with the lesions you 

 have observed? Examine (open) the remainder of the 

 small intestine and the large intestine for congestion of the 

 mucosa, petechial hemorrhages, etc. If these are present 

 how were they produced! What general conclusions can 

 you draw regarding the action of vanadium and of the 

 strong alkalies! 



EXPERIMENT CLXVIII. 



Acid, Alkali Rhubarb, Croton Oil, Magnesium Sulphate. 



(Dog: Antagonism of Acids and Alkalies, Absorption 



and Excretion of Rhubarb, Local Action of Croton 



Oil and Magnesium Sulphate Moreau's 



Experiment.) 



1. Etherize a dog and arrange to record blood-pressure 

 and respiration. Insert a bladder cannula (or catheter) 

 and collect the urine. Test some urine at once by adding 

 a little ten per cent sodium hydrate to a few cubic centi- 

 meters of urine. If no color change occurs add a drop or 



