148 THE INTERNAL SECRETIONS—1920 
It is believed to be, at first, functional and caused by 
hypertonus of the arterial musculature, but later on 
it assumes a partly organic character, the result of 
changes in the arterial walls. Barker believes that the 
different types of chronic arterial hypertension prob- 
ably represent different stages in the development of 
the same fundamental process which may advance with 
variable rapidity and with variable associated involve- 
ment of cardiovascular, renal, cerebral, and other 
structures in different cases. This author then goes on 
to call attention to the general changes which are 
fundamentally responsible for the condition of high 
blood pressure, and he states that in order to prevent 
the development of this pathologic process underlying 
high blood pressure “one should first get himself well- 
born without constitutional inferiorities’” and then 
should avoid intoxications and infections and live a 
well-balanced life, so ordering his activities that he can 
satisfy his physical, economic, social, educational, 
esthetic, and ethical desires in a well-balanced manner. 
For many years it has been considered fundamental 
that toxemias favored high blood pressure and that 
they did so first by causing an overactivity of the cir- 
culatory system resulting in changes in the heart and 
blood-vessels. Also that the toxemia irritated the 
actual glomerular tissue of the kidneys and, there- 
fore, made changes which tended toward what the 
French have called “renal impermeability.” Later our 
ideas have veered a little, and it is now considered pos- 
sible and probable that irritation of the blood-pressure- 
raising mechanism of the adrenal glands, by means of 
the poisons produced in the alimentary canal and else- 
where, results in an increased activity of this pressor 
mechanism and in this manner produces a functional 
high blood pressure. 
Be this as it may, there is no doubt that high blood 
pressure is merely a single manifestation of a serious 
