MWIHKK ()K I ACTuiiS IN\..|.\ 



151 



tively and the other or others to other regulatory mechanism of 

 metabolism in the organism. It may well be thai one of our I 

 is the same as that which causes hypothyroidism; another a 



which causes hypopituitarism, and the third that which inhibit* the 

 normal development of the genitalia, such as v functioning in 



dystrophia adiposo-genitalis. This is, indeed, speculation How< 

 the speculation is an attempt to give a concrete form to the ideal 



multiple factors in build. 



If we assume three independent factors tor build, it does aol follow 

 that these are present in all families. Just as it has been demon- 

 strated that in different strains of mice there arc m BOD . m 



Fig. 53. — Solid figure (model) giving distribution <>f relative chest-drth ! 



from birth to 20 years, reading from left to rinht. The mean index "f build 

 age is centered on the curve of development of relative chest-girth. The i 

 chest-girth is indicated in percentages passing from 1 1 »« • bottom t-> th< 

 figure. The solid figure is illuminated from the upper pari of th 



others only 2 factors for susceptibility to cancel. -... apparently, it is 

 with build. In certain families the distribution <A build in the progeny 

 is best accounted for on the hypothesis that, in such fa mi lie-. th< 

 only two gametic factors for build. In other families there apr> 

 be only one gametic factor for build. 



It has been repeatedly pointed out that in many eases where mul- 

 tiple factors are invoked to explain the genetics! results, the results 

 can be equally well explained on the theory of blended inherit 

 The advantage of the factorial theory is that it brings under on 

 of heredity even these most difficult ease- of apparently blending 



