GENETIC TYPE AND THE ENDOCRINES 325 



60 shows two giant F 2 bassetkoimd-bulldog skulls (figs. 1 and 

 ■4) and two pure St. Bernard skulls (figs. 2 and 3). All four 

 skulls were reduced to the same degree. The heavy wide 

 muzzle of the St. Bernard skull is seen to be closely imitated 

 by the bassethound-bulldogs, and the set and occlusion of 

 the teeth in both are similar. The giant skull in figure 14 

 (pi. 57), from 991 6 , is equally as pronounced for St. Bernard 

 type as arc the skulls in plate 60. 



Figure 1 in plate 58 (991 S ) is the F 2 hassethound-bulldog 

 which furnished the skull in figure 14 of plate 57. He is seen 

 to be of giant frame, and persons familiar with dog breeds 

 recognized in him the splendid type of the short-haired St. 

 Bernard dog, and found nothing reminiscent of either the 

 bulldog or the bassethound. 



It is of peculiar interest to find giant size of the entire 

 body as well as overgrowth of certain parts, and also dwarfism 

 and deficiencies of growth, all appearing among hybrids de- 

 rived from two normal sized parent stocks. Both these op- 

 posite typed growth reactions are thought to be associated with 

 derangements of the pituitary gland, and some writers have 

 been bold enough to claim that gigantism and overgrowths 

 are brought about by the hypersecretion of a certain pituitary 

 product, the hyposecretion or absence of which results in 

 cessation of growth and dwarfism. Such reasoning presumes 

 that quite opposite pituitary conditions are related to each 

 of these directly contrasted growth responses. Certainly the 

 pituitary disturbance that might be associated witli the in- 

 ability to attain normal size could scarcely be the same as 

 that associated with an excess of growth to double normal 

 size, always provided, of course, that one accepts the pituitary 

 as the controlling element and the tissue constitution as of 

 secondary or of no importance. Whether either or both giant 

 and dwarf growth patterns are initiated through pituitary 

 anomalies, both certainly develop in the strange constitutional 

 complexes which arise from the new combinations of factors 

 occurring in the F 2 bassethound-bulldog hybrids. And still 



