268 C. N, H, LONG 



question asked so long ago by this French Academy, I believe that all, 

 including Montesquieu, would agree that our knowledge of the supra- 

 renal glands is now immeasurably greater, even though it is still far 

 from complete. The chance or chances to which Montesquieu looked for 

 future enlightenment were not soon seized by scientists, for it was not 

 until the period from 1855 to 1867 that another great Frenchman, 

 Claude Bernard, enunciated the two great generalizations that laid 

 not only the foundations of our present knowledge of the ductless 

 glands, but to use his own words established "the basis of general 

 physiology." 



The first of these is nov/ known as the doctrine of "internal secre- 

 tion." In this it was pointed out that certain specialized groups of cells 

 or organs pour their secretions directly into the blood stream and that 

 such organs could thus be termed "ductless glands" to distinguish them 

 from that group whose products passed by ducts to an internal or ex- 

 ternal surface of the body. Curiously enough Bernard first used the 

 term "internal secretion" in connection with an organ not now generally 

 recognized as an endocrine gland. This was the liver, and he coined the 

 term to describe the capacity of this organ to "secrete" glucose directly 

 into the blood stream. However a few years later he included in this 

 category the adrenals and thyroid glands. To these and certain others 

 the term ductless or endocrine glands is now more generally applied. 



Bernard's concept that the blood served as a transporting medium for 

 the products of secretion of certain organs and that these products 

 might be a foodstuff such as glucose or a more subtle agent such as a 

 hormone led in 1867 to the formulation of his general statement con- 

 cerning the relationship of the blood and body fluids to the preserva- 

 tion of the function or the organism. Bernard recognized that in the 

 higher animals all the cells and organs of the body exist in a fluid en- 

 vironment whose composition is rigidly maintained within limits that 

 are compatible with their existence. The importance of this concept 

 of the constancy of the internal environment to an understanding of 

 the physiology of the higher forms of life was not immediately appre- 

 ciated. It is only in our own time that it has been given its proper recog- 

 nition and this is largely due to the work and writings of Cannon, 

 Haldane, and Henderson. Briefly this doctrine states that not only is the 

 composition of the fluid environment of the cells kept within certain 

 narrow limits, but what is equally important, the organism strenuously 

 resists the operation of any factor or circumstance that acts to change 

 this composition. 



