EXTIRPATION OF ANTERIOR LOBE OF HYPOPHYSIS. 127 



in aquarium jars with soft cistern water lived with very little 

 mortality until I killed them. They had ceased to grow because 

 of overcrowding in narrow quarters. The serious effects of our 

 water supply upon normal tadpoles were noted in a series of 

 experiments upon removal of the thyroid, to be published later. 

 In these both the thyroidless tadpoles and their controls began 

 to show a remarkable twist in their tails when they reached a 

 length of about 25 mm. on June 8, 57 days after the operation. 

 At this time they began to show a high mortality. This was 

 even more marked in the controls than in the operated ones. 

 Only a very few that had been deprived of the hypophysis re- 

 mained alive at this time and they were not far enough advanced 

 to show these modifications. 



This whole matter will be the subject of extensive work next 

 spring in an effort to determine whether the high mortality 

 among the tadpoles deprived of the hypophysis is due to a re- 

 sulting susceptibility to some specific substance in the water. 

 We should be able by these means to trace out some features in 

 the influence of the hypophysis upon metabolism. 



There was marked retardation in the development of the 

 limb buds. This was quite evident in the 24 mm. specimen 

 killed July 2. The operated tadpole of this stage had limb buds 

 234 micra while in the control they were 532 micra in length. 

 According to the reports of a friend who kept the 30 mm. tadpole 

 under observation up to the time of its death, August 30, the 

 limb buds remained strictly rudimentary. At this time the 

 controls had long before undergone metamorphosis. In these 

 regards my work is in complete accord with that of Adler and 

 Smith, namely, the removal of the hypophysis prevents the hind 

 legs from developing beyond a rudimentary condition, and 

 causes the tadpoles to remain in a larval state. 



The internal structure of the few operated tadpoles that reached 

 sufficient size was studied in comparison with the controls. 

 The stages thus investigated were of 15.5 mm., 16.5 mm., 21.5 

 mm., and 24 mm. length. One that reached 30 mm. length 

 unfortunately died without being preserved. Especial attention 

 was given to a study of the thyroid and thymus glands and to the 

 gonads. A more cursory examination of other organs was made, 

 but failed to show any noteworthy features. 



