So, as school education will have to take serious account of endocrine anomalies and possibilities, will the institution which selects and trains for a career. Vocational misfits have aroused the ardor of our efficiency experts. And again, the sweeping psychological attack has beaten its head against the stonewall of ignorance of constitutional predispositions and tendencies of material. The attempt to erect psychologic types for vocational selections could never make much headway because it could only flounder in a swamp of metaphors, product of the vices of its methods. Not that anyone would wish to discard at all the psychologic mode of approach. But no science, in the sense of accurate examination, was possible, in the matter of classification for vocation, without the insight into the physiology of the candidate that the analysis of his endocrine formula will provide.
One need not dilate upon the value of such an examination. Civilization has not yet learned how to pick its personnel. And so artists and scientists, philosophers and politicians, financiers and religious leaders, arise and survive by the operation of the laws of probabilities and chances, rather than by any intelligent selection and cultivation of material. The case, indeed, is simply a subdivision of the vast subject: haphazard muddle in the conduct of life. A cry has been raised for the superman, and a cry has been raised for a method of anthropometry. For the lack of these two, it has been said, all governments have been doomed to defeat. The study of the endocrines will by no means supply a panacea. But as it will furnish a means of approach to the determination of how men and women are built, and why they are built differently, no one can gainsay the tremendous advantages to the nation that will proceed to classify its population accordingly, and know its strength and weakness in terms of the actual generators of success and failure.
Suggestions have been offered in the preceding pages of concrete applications of endocrine knowledge to the understanding of behaviour, of the genius and commonplace, criminal and Puritan. And in the chapter on historic personages, we tracked some of the story in detail. This vein when explored will quarry untold riches. It has been observed that financiers of mark, like great musicians, are special pituitary types. Also that the financiers are voracious meat eaters and the musicians inordinately fond of sweets. Differences in anterior and posterior predominances might account for this. That we are playing here with no phantasy is proven by the fact that we can effect changes of tastes as well as of intellectual direction by appropriate feeding of various glandular extracts. Just as much, indeed, as we can influence sex susceptibility, and the reaction to sex stimulation, by the artificial introduction from without of the proper hormones.
FATIGUE AND INDUSTRY
In industry, business and profession, the biologist will come more and more to be called as consultant. Labor unions as well as the large employers of labor, and their employment managers have given much thought to the problem of fatigue. Just what fatigue is, why different individuals tire at different rates, why some are constructed for monotonous routine while others must have constant variety and change, the relation to accidents and to quantity output, are a few of the major lines of inquiry upon which the endocrines obviously have a large bearing. To the employment manager, labor turnover and the selection of personnel are adjacent fields of research.
Fatigue as an endocrine deficiency—a depressed state of one or more of the glands of internal secretion, abolished when its normal functioning is restored—is a general principle from which departures of exploration of sub-problems will proceed. An endocrine organ will secrete at a certain rate. When it is stimulated excessively, it will eject extra amounts of its secretion. How long the period of excessive stimulation may last must depend upon the secretion potential or margin of reserve of the cells, varying from organ to organ, and from individual to individual. After that, exhaustion and failure follows, with the onset of the symptoms of fatigue.
A pretty demonstration of this process has been worked out in the electrical stimulation of muscle. If a muscle, say the biceps, is irritated by an electric current, it will contract. As the strength of the current is increased, the degree of contraction becomes greater. A sort of stepladder effect of increasing contractions may be thus obtained. After a time, the electric shocks cannot cause a greater contraction, but only a lesser. And if continued, the muscle will cease to function because of fatigue. If now, when the muscle begins to lag in its response, and its contractions to decrease, one injects into a vein extracts of thyroid, parathyroid, or adrenal glands, they will immediately reinvigorate the failing contractions. The injections must be made before the fatigue is carried to the point of absolute exhaustion. It follows that these glands normally pour into the circulation substances which counteract the effect of fatigue substances, and in fact make possible muscular recuperation from fatigue throughout the day as well as in emergencies and crises.
Fatigue, conventionally recognized, is something acute and urgent. As such it means a violent draining of the endocrine wells. But there is also a chronic fatigue, which has been dignified with the name of Fatigue Disease. Bernard Shaw once asked for someone to tell him the name of the germ causing the symptoms of overwork. That being impossible, he will have to be satisfied with the answer that it is not a germ, but an internal secretion, or rather a defect of internal secretion that is the cause.
Whether or not the adrenals have been damaged by past experiences, and upon their capacity to respond to the necessities of an occasion, fatigue reactions primarily depend. A quotation from Sir James MacKenzie, most distinguished of modern English students of medicine, summarizes the matter neatly. "Abelous, and Langlois and Albanese have studied the relation of the adrenal bodies to fatigue…. They infer that the muscular weakness following removal of the adrenals is due to toxic substances. In view of our present knowledge of the physiological action of adrenaline in its various forms, it seems more probable that the weakness is to be explained by the absence of the normal tone producing internal secretions of the bodies in question." In other words, the adrenals regulate muscle tone. They produce nature's tonics for weary tissues. The chronic lassitude of thousands of our generation, suffering from "that tired feeling," may be put down to chronic adrenal insufficiency.
It requires no superlative imagination to see that an adrenal poor subject does not belong upon a job that involves muscle stress over a long period, or indeed fatiguing conditions of any sort. Nor that a thyroid poor individual is not the best choice for a position that demands a keen, alert body and mind. In the selection of executives, the nature and stamina of the pituitary will undoubtedly be taken very seriously in the near future.