14 



INTRODUCTION 



Table 2. Steps in establishing direct and indirect actions of 

 TWO interacting hormones 



experiments on rats 



RESULT 



controls on litter 

 mates preferably of 



SAME SEX 



RESULT 



1. Operative removal 



of the adrenal cor- 

 tex 



2. Op: as 1 + injec- 



tions of pure cor- 

 tex extract 



3. Op: removal of 



Adhp : (including 

 source of ACTH) 

 leaving cortex in- 

 tact but unstimu- 

 lated 



4. Op: as 3 + injec- 



tion of one frac- 

 tion of Adhp : ex- 

 tract (= ACTH) 



5. Op: removal of 



Adhp: and cortex 



6. Op: as 5 + injec- 



tions of ACTH (as 

 4) 



7. Op: as 5 - cortex 



extract (as 2) 



Death 



Survival* 



Death 



\a. Mock operation 



2a. Op : as 1 -f other 

 injections t 



3a. Mock operation 



Survival 



Death 



Survival 



Survival* 



Death 

 Death 



Survival* 



4a. Op: 3 + injec- 

 tions of any 

 other Adhp : ex- 

 tracts 



5a. Mock operations 

 of equal severity 



6a. Op: as 5 + injec- 

 tion of other ex- 

 tracts 



7a. Op: as 5 + injec- 

 tion of other ex- 

 tracts 



Death 



Survival 

 Death 



Death 



* For as long as injections are maintained. 



t NaCl injection can mitigate the effect of cortex removal for some 

 time (§ 5.311). 



Adhp = adenohypophysis. ACTH = adrenocorticotrophin. 



Argument: Experiments 1 to 4. The result of removing either the cortex 

 or the adenohypophysis is the same (1 and 3). So is the effect of 

 injecting extracts of the gland removed, i.e. replacement of either 

 missing hormone can maintain life (2 and 4). The operation itself and 

 post-operative shock as causes of death are ruled out by survival of 

 controls {\a and 3a), on which operations of comparable severity are 

 performed, but without touching the endocrine organs. Injections of 

 other materials are shown by controls to be ineffective {2a and Aa). 

 By fractionation of the extracts of the adenohypophysis, and by testing 



