cr? ‘ 
May 26, 1923] 
ducts of gastric digestion into the small intestine evokes 
in the epithelial cells lining this tube the development of 
a substance—secretin—which is absorbed by the blood- 
vessels and carried round to the pancreas, liver, and 
intestinal glands, so as to bring about the simultaneous 
NATURE 
695 
widespread effects on the most diverse tissues of 
the body. This extract is sold under the name of 
“‘pituitrin.” According to the conditions existing at the 
time of administration it may increase or diminish the 
flow of urine ; it causes rise of blood-pressure and con- 
” 
; 
} 
} 
_ secretion of the three juices the co-operation of which 
is necessary for the complete digestion of all classes of 
foodstuffs. 
These are examples of the restricted action of the 
chemical messengers, resembling closely the reactions 
_ brought about through the intermediation of the 
traction of the uterus, as well as of all other unstriped 
muscle, such as that of the intestines. For these 
purposes it has come into actual practice as a thera- 
peutic agent. Its presence in minute quantities in the 
blood seems to be a necessary condition for the con- 
tractility of the blood capillaries, so that it becomes a 
central nervous system, so that we are justified in 
speaking of them as chemical reflexes. Other hormones 
have a much wider action, which may extend to all 
or almost all the cells of the body. Our knowledge of 
_ these is scarcely half a century old, and began with the 
: discovery in England of the relation of myxcedema and 
_ cretinism to atrophy or failure in development of the 
: thyroid gland. Later research has shown that these 
_ conditions are due to the absence of a secretion manu- 
~ factured by the thyroid. This secretion has been 
isolated and has been found to be a substituted iodine 
derivative of tryptophane. On its constant presence 
in the blood depends the normal growth and metabolism 
of all the tissues of the body. Since these include the 
central nervous system, development of the mind is 
affected as well as that of the body. Absence of this 
secretion in early life results in the production of a 
pr. 
j 
regulator of the supply of the nutrient blood to all the 
tissues of the body. 
© It is not surprising that these later achievements 
of physiological research have impressed public 
opinion and have had a marked effect in the United 
States, where the public interest in things medical is 
aroused every week by popular articles on medical 
Science in the Sunday papers. The arousing of un- 
educated curiosity has its dangers as well as its value. 
Sensationalism and imagination have not only rushed 
ahead of the ascertained facts but have also opened the 
way to a shameless exploitation of the uneducated 
curiosity which has been aroused. It is not so many 
years since bits of animal organs were regarded as 
essential ingredients of remedies for disease as well as 
for love-philtres and charms. The heart of the tiger 
or-of the brave enemy was eaten to give courage to the 
victors, and at the present day we find a therapeutics 
stunted cretin. Increased secretion by a hypertrophied 
f gland causes increased rate of metabolism, quickened 
j _ heart-beat, excitability which may culminate in mania, 
changed personality—all of which may disappear when 
advertised and exploited which is nothing less than a 
return to the superstitious practices of the middle 
ages. The principle is simple. If the kidney is 
_ the gland diminishes in size or the hypertrophied portion 
: is removed. 
Still more wonderful and widespread in its effects is 
the pituitary body. This consists of two parts—one of 
which is derived from the brain, the other from the 
back part of the buccal mucous membrane of the 
foetus; each part is only about the size of a pea. 
Increased activity of the anterior part gives rise to 
gigantism in the growing animal, or, when it affects the 
adult, the overgrowth and deformation of face, hands, 
and feet, which is known as acromegaly. If it were 
possible to isolate and administer the chemical sub- 
stance responsible for these growth changes, we should 
be able to rival the effects of the ‘‘ Food of the Gods” 
imagined by Mr. H. G. Wells. Atrophy of this part 
causes diminished growth, excessive fat production, and 
a condition of infantilism, with lack of development of 
the sexual functions. The posterior part, which in 
appearance seems to consist of little else but neuroglia, 
the supporting tissue of the central nervous system, 
produces some substance which can be extracted from 
it by boiling water, and has, in infinitesimal doses, 
NO. 2795, VOL. 111 | 
affected, dried kidneys of animals are administered ; 
ifvthere is a failure of sexual powers, ovaries or testes 
ate administered in the same way. It is only necessary 
to locate the disorder in order at once to apply the 
appropriate remedy. Charlatanism finds an easy and 
profitable prey in the curious and uneducated. The 
only protection against its attacks lies in more complete 
education, and it is for this purpose that such a book as 
that of Dr. Benjamin Harrow is useful. The author 
is apparently not a medical man, but is an associate 
in physiological chemistry of Columbia University. 
Though the restriction of his knowledge and experience 
is apparent, the book is nevertheless of value as a 
dispassionate and objective statement of the facts 
which are so far known as to the internal secretions. 
Throughout the author maintains a proper sceptical 
attitude in face of the uncritical or prejudiced state- 
ments which have been put forward by clinicians as 
to the influence of various preparations of the organs 
involved. 
oThere are a few errors of fact, as well as certain 
questionable conclusions, which might well be omitted 
