EDUARD UHLENHUTH 



361 



Experiment 4. — In this experiment (Series XXXVII2 and Series A) 

 the controls were underfed and therefore cannot be used for compari- 

 son. Both the experimental as well as the control series were obtained 

 from the eggs of the same female; but the control animals were under- 

 fed for several weeks during the larval period and the experimental 

 animal, which was fed abundantly on anterior lobe from the beginning 

 of its life, was kept in distilled water during the larval period, which 

 tends to retard growth. The results are seen in Fig. 5. The anterior 

 lobe-fed animal measured 258 mm. at an age of 84 weeks; i.e., 58 mm. 

 more than the largest normal animal kept in the laboratory and 50 

 mm. more than the largest specimen of the eastern race. At present, 

 however, it is growing very slowly and less vigorously than the ani- 

 mals of Series A.^* 



TABLE III. 

 Hypophysis-Fed Amhystoma tigrinum, Experiment 3. 



86 weeks. 



Controls . 



Anterior lobe-fed animals . 



Weight. 



mg. 



38,500 

 40,200 

 31,100 



95,700 

 84,300 



^^ Since this paper went to press, Dr. Leonhard Stejneger, head curator of 

 the United States National Museum, was kind enough to go over the entire col- 

 lection of the museum and let me have the measurements of the largest specimens 

 of the species Amhystoma opacum and Ambystoma tigrinum. Since the measure- 

 ments are based on a far larger collection of material than my own data reported 

 in the preceding pages, they are of greater importance and will be added below. 

 They confirm the opinion expressed in this article that feeding the anterior lobes 

 of hypophysis produces gigantism in salamanders. 



