ETIOLOGY AND PATHOGENESIS OF SPASMOPHILIA It is necessary to make as sharp a distinction as possible between the causes themselves and the conditions which favor the development of the diathesis on the one hand, and the clinical phenomena to which the diathesis gives rise on the other.
Many authors seek the cause of tetany and the overexeitability the nervous system on which it is based in a general infection, exactly as has been done in the ease of rachitis. The arguments constantly presented are the great frequency of the diseases at certain times of the year, and in certain localities, which practically amounts to an epidemic; but we are without any definite proof, because the facts adduced in support of the argument are either imperfectly established or capable of some other interpretation. In the absence of compli cations, the disease runs an absolutely afebrile course, so that there is nothing which could suggest the idea of infectious disease to an un prejudiced observer.
Kassowitz's theory of a respiratory injury, the weak points of which we have already pointed out, is also based on the massing of the cases wilich is observed both as to time and place; nor is the theory of a status lymphaticus, which was first promulgated by Paltauf and by Eseherich, applied to tetany and the tetanoid manifestations: altogether satisfactory, for even if we accept the status lymphatieus as a well defined constitutional anomaly, which is open to grave objection, the eonclition is found only in a certain proportion of spasmophile children. Many of them in faet are quite lean and imperfectly developed, in sharp contrast to the pasty, "lymphatic- type.
The theory that the functional anomaly of the nervous system, witich forms the basis of tetany, is due to a functional absence of the parathyroid glands or epithelial corpuseles, rests entirely on theoretical consideration and is devoid of pathologic proof. With regard to this subject, which has recently elicited a great deal of discussion, we shall refer the reader to the comprehensive essays of Biedl and Chvosteck, contenting ours.elves with the statement that, while the possibility
of producing in animals a convulsive state which rapidly ends in death and has been called tetany by removing all four of the epithelial bodies may be regarded as proven, it has not been demonstrated either that this "tetany" is identical with the tetany of childhood, nor have any anatomical changes in the parathyroid glands been observed in in fants the subjects of tetany or spasmoplailia.
My own comparatively few histologic examinations of these organs have so far given absolutely negative results.
It is certain from clinical observation that the quality and quantity of the food may bring on a spastnophile diathesis, and also cause it to di.sappear. This is accordingly a factor of indisputable importance, but we are far from understanding its mode of action, and for the pres ent must be contented to attribute spasmophilia to sotne unknown metabolic disturbance.
Experimental physiology has taught us that the irritability of a peripheral nerve can be influenced by salt solutions capable of modi fying osmosis, and this suggests the possibility that wc may be dealing with a disturbance of salt metabolism. With this in mind Czerny insti tuted a series of chemical examinations of brains, which was carried out by' Quest, and which showed a diminution in the calcium salts in the brains of tetanic children. The study of the calcium salts was suggested by Sabbatani's discovery- that the irritability of the cerebral cortex to the electric current increases as the calcium content diminishes. If subsequent investigations on a larger scale—which in view of the fact that the gray and the white substances do not share equally- and con stantly in the building up of the growing brain seem most desirable— should show that Quest's findings have the importance of a law, this would give us another clue to the explanation of spasmophilia and its dependence on diet.