THE HORMONES, THEIR PRESENT 

 SIGNIFICANCE, THEIR FUTURE 



GREGORY PINCUS, The Worcester Foundation for Experimental 

 Biology, Shrewsbury, Massachusetts 



Introduction 



With the accelerating increase of our knowledge of the 

 biochemistry of the hormones, any summary assessment of their 

 role as biologically active substances is fated to be overmiserly 

 in description and hazardous in extrapolation. The descrip- 

 tion is overmiserly not merely because of the necessity for con- 

 densation, but also because the acquaintance of any single in- 

 dividual with the diverse and heterogeneous fields of investi- 

 gation involved is bound to be limited. The extrapolation is 

 hazardous because one is in the position of a mathematician 

 attempting to write the equation of an S-shaped curve which has 

 not yet exhibited its inflection point. To compensate to some 

 extent for inadequate acquaintance with all the data, this writer 

 will confine his observations to animal hormones and chiefly to 

 those which are active in mammals, and as a substitute for pre- 

 cise extrapolation he will offer speculations as well based as pos- 

 sible on established fact. 



To indicate the diversities which confront any student of 

 hormonology I have compiled Table I, which lists those sub- 

 stances having fairly established claims to being active internal 

 secretions in animals. A number of additional substances 



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