Chemico-Functional Integration 121 



circuit, lience tlirough the lungs and so on, around to the 

 pancreas, the typical gland-cells of which it excites into 

 activity, so that the pancreatic juice, an "external" instead 

 of an ''internal" secretion, is poured into the duodenum to 

 exercise its digestive office on the same food which started 

 the cycle of activities. 



It was with tliis substance particularly before tlieir minds 

 Hiat tlic authors adopted the name Iwnnone to designate 

 substances which act tlius. "The group of substances re- 

 ferred to," says Bayliss, "which includes adrenaline and the 

 various internal secretions, is characterized by the prop- 

 erty of serving as chemical messengers, by wliicli the activity 

 of certain organs is coordinated with that of others. They 

 enable a chemical correlation of the functions of the organ- 

 ism to be brought about through the blood, side by side 

 with that which is the function of the nervous system." ^ 



Tliis reference to the side-by-side activities of chemical 

 messengers and nervous system in integrating the organism 

 touches a subject of the utmost importance. Considera- 

 tion of it must, however, be deferred until we have looked 

 a little more into the nature of hormones. 



The Nature of the Actii*e Substances in Internal Secretions 



That the peculiar iodine-rich albuminous substance ob- 

 tained from the thyroid by Baumann in 1895 and since 

 observed by other investigators, contributes in some essen- 

 tial way to the action of the secretion of tliis gland is the 

 belief of apparently a large majority of autliors (Bayliss, 

 Kppinger, Howell, etc.), but not of all (Luciani). In view 

 of the uncertainty on the point Schafer's proposal "to ex- 

 press our ignorance by a term which implies no theory" 

 may well be accepted, with the proviso that the term pro- 

 posed be really taken as evidence that sowefhing though 

 not everything is known about the substance. A part of 



