THE PITUITARY GLAND 19 



All the ductless glands are studied by four methods. 

 We have to find the effects, firstly, of removal in 

 animals ; and secondly, of the injection or ingestion 

 of extracts. We have, thirdly, to make chemical 

 analyses of the extracts, to isolate any active principle. 

 Finally, a clinical study of symptoms in man associ- 

 ated with any abnormalities of the gland may be 

 expected to throw a light on the problem, and the 

 effect of treating these conditions will also need to 

 be known. 



These are here set forth in the rational, not in 

 the historical order. It may be said at once that 

 the active principle or principles have not yet been 

 isolated. 



THE EFFECTS OF REMOVAL OF THE PITUITARY 

 GLAND IN ANIMALS. 



It is so difficult to remove the organ from its well- 

 concealed nest that the earlier published results 

 inspired no confidence. It was said that the animals 

 died, but the injury to vital structures was necessarily 

 great, and it has been remarked that the result 

 would probably have been equally fatal if the 

 operator had removed the dorsum sellse instead of the 

 gland ! But the careful and repeated observations 

 of Paulesco on twenty-two animals, and of Gushing 

 on about 100 puppies, have completely established 

 confidence in the statements now before us. 



It is proved that removal of the anterior lobe alone, 

 in dogs, produces just as much effect as removal of 

 the whole gland, but that a removal limited to the 

 posterior lobe causes no symptoms at all. 



