If the increase in irritability is very great, active contractions can be elicited by merely stroking the cheek :Schultze's phenomenon) instead of tapping it lightly with the percussion hammer. On the other hand, if the increase in irritability is slight, the contractions are feeble and often appear only in one branch of the facial. It is obvious that the phenom enon can be elicited with difficulty, or not at all, if the child is crying.* The pathognornonic importance of the facial phenomenon is much greater, in our opinion, than is usually believed, a point which will be diseusse.d again later.
The question of determining the mechanical overexcitability in other peripheral nerves has already been discussed.
Erb's phenomenon consists in overexcitability of the peripheral nervous system to a galvanic current, and in formulating the charac teristic contraction law of Thiemich and Maim is the most constant and most sensitive indicator for determining the abnormal irritability which is the basal condition, as we have already explained above. It should be emphasized, however, that the galvanic overexcitability need not necessarily be of exactly the same degree in all the nerves at the moment of examination, and that its intensity—in the median nerve, for instance—is not always proportional to the clinical mani festations and the remaining latent symptoms.
The subdivisions of the latent symptoms into obligate (Thie.mich's and Erb's phenomenon) and facultative (mechanical excitability, facial phenomenon or laryngospasm) which is practiced by- many authorities, lacks sufficient justification and ought to be discarded; but as the expression spasmophile diathesis is more descriptive and more comprehensive, it would be advisable in the future to restrict the term latent tetany or tetanoid conditions to those cases which exhibit the Trousseau phenomenon.
The clinical course of tetany exhibits many variations. As a rule, the individual attack does not. last more than a few hours, although it may continue for 12 hours or an entire clay; the convulsion then usually relaxes, but is repeated after an interval of a few hours, and so on for several clays, with several intervals of freedom. The entire dura tion rarely exceeds two or three days; at least, we observed such a clinical course even at a time when the remedies at our command in all probability did not influence the course of the disease as markedly as we. have now learned to do.
While the above course is observed in the majority of the cases there is a small minority in which the earpopeclal convulsion loses more or less of its intermittent character and produces a permane.nt spasm. In these cases the demonstration of latent symptoms, particularly the most delicate of these symptoms, namely, overexcitability, is of (le cisive importance in cleciding the question whether phenomena of this kind may be regarded as tetany or not. It, is almost needless to say after
what has been stated that, with Fleiner and nanny others, we hold fast to the view that convulsions in which over-elcetrical excitability is absent have nothing to do with tetany. According to this view we include under the head of tetany, first, those rare cases characterized by great severity which others as well as myself have observed beyond any question of doubt, and in which the inMvidual attacks lasted many days, while the entire duration of the disease WaS measured by months.
Second, the cases of general hypertonia which occur after certain nutritional disturbances (particularly the condition produced by arti ficial feeding) and which Gregor first studied and described with regard to their electrical behavior. On the other hand, most uases of general muscular hypertrophy in sick infants, and the conditions described by Escherich as pseudotetanus have nothing whatever to do with tetany.
For practical reasons, we shall here append a description of these conditions, although they exhibit only a superficial and momentary resemblance to tetany.
General Muscular Hyportonias Without Spasmophilia. —The mus cular hypertionas—also known as persistent spasm (Zappert) or "myo tonia of the newborn" JIochsinger*)—have been recognized since the appearance of Czerny and Moser's articles on the subject as a fre quent symptom of severe nutritional disturbances. The convulsions which may predominate either in the flexor or in the extensor muscles vary in intensity and in duration from a few days to several weeks, but are never intermittent. The position of the arms and legs may simulate that of tetany; indeed pressure on the nerves and vessels in the bi cipital groove niay cause an increase in the muscular tone. At the sanne time, the child usually makes a fist, a phenomenon to which lIochsinger attributes undue importance. Ile speaks of a fist pheno menon which he likens to the Trousseau phenomenon. But, although Itochsinger contends that the two symptoms are frequently confused, there is no reason to think that the confusion has ever led to an error in diagnosis. These prominent spasms practically always occur ill chil dren only a few weeks or months old; very rarely during the period of childhood which furnishes the chief contingent of tetanic patients (com pare page 316); the convulsions almost without exception occur in children suffering fron) acute septic processes and exhibiting other symptoms of cerebral irritation or palsy. Nothing positive is known in regard to the pathogenesis of these conditions. The treatment is the same as that of the primary disease.