CONVULSIVE DISEASES The fact that children in general, and particularly those in the first two years of life, are much more frequently attacked by convulsions than adults long ago arrested the attention of physicians and gave rise to many theories for its explanation. It does not appear necessary to enumerate all these theories and we shall therefore mention only the following: The cause of the frequent occurrence of convulsions was assumed to reside either in the peculiarities of the diseases to which children are subject, and which differ from the diseases of adults, or in peculiarities of the childish organism or nervous system; or filially, in both these pathologic and physiologic factors.* The most important period in the history of infantile convulsions is marked by the promulgation of Soltmann's hypothesis. This observer found by experimental investigation that in newborn dogs, cats, and rabbits the motor cortical areas discovered by Fritsch and Hitzig can not be excited electrically, and are probably incapable of functionating. He concluded therefore that they are incapable of exercising either an innervating or an inhibiting influence on subcortical motor centres. In order to apply these discoveries to the human newborn infant there suggested itself a method which promised success, namely, a compari son of the medullary striation in the animals experimented upon and in human infants. Soltmann's investigations in this direction, which harmonize with similar ones made by other observers, showed that the human infant requires from twelve to eighteen months to attain the stage of development of an animal front ten to twelve days old, in which irritation of the cortex already produces movements on the opposite side of the body. From this Soltinann concludes that the inhibiting function is not developed, and does not become effective before that period in man. These results appeared to explain the frequency of convulsions in infants under eighteen months of age. Another interest ing result of these animal experiments is that the nerves of newborn animals are much less irritable, and that even a small number of single electric stimuli in the second produces tetanus in a nerve-mu.scle prepa
ration taken from a newborn animal, while under the same conditions in the adult animal each individual stimulus elicits a single contrac tion which can be distinctly separated from every other. In harmony with this phenomenon Soltmann found that the myogram of the single contraction in the newborn is flatter and that the contraction is more sluggish than in the adult animal.
Investigations by the same author to determine the time at which these abnormal conditions in the newborn change to the conditions as we know them in the adult, yielded a further noteworthy result, which appeared to be calculated still further to elucidate the frequent oecurrence of convulsions during the later part of infancy. It was found that the irritability of the peripheral nerves attained the maxi mum, or even exceeded the maximum for a later period of life at a more rapid rate than that of the full development of the inhibitory centres.
"At about this time," Soltmann writes in speaking of the period between the fifth and the ninth months of life, " the irritability of the periph eral nerves is already quite considerable, perhaps even greater than in the adult; while conversely the mechanism of inhibition and the voli tional faculties (the psychomotor cortical centres), although they have begun to develop, are by no means sufficiently powerful or sufficiently definite in their action to offer an efficient bar to the ready transmission of reflexes. This explains," Soltmann goes on to say, "that a quite insignificant irritation affecting the infant (luring this period of life, even if it does not appear to exceed the bounds of the physiologic, as, for example, the eruption of a tooth, which at another time would not produce any disturbance of any kind, is quite sufficient to bring on a convulsion." The objections that were raised against Soltmanffis doctrine of "physiologic spasmophilia" or "increased disposition to reflex irrita tion" in infancy and their untenability will be referred to again later.