He shows no impairment as to external sensations; on the other hand, internal sensations, such as satiety, illness, etc., are blunted. His power of attention seems sufficient, both at play and in school and when questioned. Neither does his memory show anything abnormal. Emotionally, he is below the normal level; he says that he is afraid of thunder; occasionally he shows annoyance when disturbed; but it is equally certain that he never becomes angry, never turns pale and never blushes, as the result of any excitement. He is of an indifferent disposition and is passive in manner; he is good natured, or rather, a certain degree of apathy makes him appear so.

All things considered, his mental development may be described as that of a three-year-old child; only that he differs from children of that age in his lack of vivacity and in his complete development of articulate speech (it should be noted, in regard to the diagnosis of age made by so distinguished a psychologist as De Sanctis, that he judged the child to have a psychic development corresponding to the age of three years); while we, studying the general measurements of the body, determined that they correspond to three different ages, namely, two, three and four the average of which is precisely three; while the stature, which is the index of development of the body as a whole, corresponds almost exactly to that average of three years (0.870 m., 0.864 m.).

Pathogenesis of Infantilism.—At this point it might be asked: Why do we grow? We hide the mechanism of growth under very vague expressions: biological final causes, ontogenetic evolution, heredity. But, if we stop to think, such expressions are not greatly different from those which they have replaced: the divine purpose, creation.

In other words, a causal explanation is lacking. But positive science refuses to lose itself in the search after final causes, in which case it would become metaphysical philosophy. Nevertheless, it may pursue its investigations into the genesis of phenomena, whenever the results of experiments permit it to advance.

So it is in the case of growth; certain relatively recent discoveries in physiology have made it possible to establish relations between the development of the individual and the functions of certain little glands of "internal secretion." Now, the discovery of these relations is certainly not a causal explanation of the phenomenon of growth, but only a profounder analysis of it.

Hitherto, we have considered the organism in regard to its chief visceral functions: in speaking of macroscelia and of brachyscelia, we considered the different types in relation to the development of the organs of vegetative life and the organs of external relations: the central nervous system, the lungs, the heart, the digestive system. Our next step is to enter upon the study of certain little organs, which were still almost ignored by the anatomy and physiology of yesterday. These organs are glands which, unlike other glands (the salivary glands, the pancreas, the sudoriferous glands, etc.), are lacking in an excretory duct, through which the juices prepared for an immediate physiological purpose might be given forth; and in the absence of such excretory tubes, their product must be distributed through the lymphatic system, and hence imperceptibly conveyed throughout the whole organism.

One of these glands, the one best known, is the thyroid; but there are others, such, for example, as the thymus, situated beneath the sternum, or breast-bone, and much reduced in size in the adult; the pineal gland or hypophysis cerebri, situated at the base of the encephalon; the suprarenal capsules, little ear-shaped organs located above the kidneys. Up to a short time ago, it was not known what the functions of such glands were; some of them were regarded as atavistic survivals, because they are more developed in the lower animals than in man, and consequently were classed with the vermiform appendix as relics of organs which had served their functions in a bygone phylogenetic epoch and remain in man without any function, but on the contrary represent a danger through the local diseases that they may develop. The cerebral hypophysis was in ancient times regarded as the seat of the soul.

These glands are very small; the largest is the thyroid, which weighs between thirty and forty grams (1 to 1-3/5 oz.); the suprarenal glands weigh four grams each (about 60 grains); the hypophysis hardly attains the weight of one gram.

The importance of these glands began to be revealed when antiseptic methods rendered surgery venturesome, and the attempt was made (in 1882) to remove the thyroid gland. After a few weeks the patient operated on began to feel the effects of the absence of an organ necessary to normal life: effects that may be summed up as, extreme general debility; pains in the bones and in the head; an elastic swelling of the entire skin; enfeebled heart action, and anemia; and on the psychic side, loss of memory, taciturnity, melancholy. After the lapse of some time the patient showed such further symptoms as the shedding of the cuticle of the skin, whitening of the hair and facies cretinica.

But when Sick undertook to operate upon the thyroid of a child of ten, the deleterious effects of interrupting the above-mentioned function of the gland manifested itself in an arrest of development; at the age of twenty-eight the patient operated on by Sick was a cretin (idiotic dwarf) 1.27 metres tall (average stature at age of ten=1.28 m.). Since that time certain diseases have been recognised that call to mind the condition of patients who have undergone an operation for removal of the thyroid glands, and in which the subjects have suffered from hypothyroidea, or insufficient development of the thyroid.