608 LEWELLYS F. BARKER 



the metaphor ho continued, the anodal opening contraction (AOC) can he 

 used. The kathodal closure contraction (KCC) permits of a view of even 

 -normal galvanic temperature;" its readings are of value for indicating 

 hvperexcitability only when contractions occur with current strengths 

 lower than one milliampere. The anodal closure contraction (AGO) is 

 wholly unsuitable for testing hyperexcitahility, and hence one nee 



make use of it. ... 



By the aid of the technique above described, very slight variations in 

 the electrical excitability of the motor nerves can be determined. The 

 effects of a series of influences upon the excitability of the motor nerves 

 have already been studied with the help of this method. 



Summarizing the whole matter of hyperexcitability of the motor nerves 

 in sucklings, von Pirquet arrived at the following conclusions : 



1. Galvanic stimulation yields, in the normal suckling, only closure 

 contractions with currents below the limit of five milliamperes. 



2. The appearance of anodal opening contractions (AOC) with cur- 

 rents feebler than five milliamperes, when at the same time kathodal 

 opening contraction (KOC) and kathodal closure tetanus (KCTe) are 

 absent, is characteristic of a mild hyperexcitability, which one can desig- 

 nate by the term "anodal hyperexcitability." 



3. "Anodal hyperexcitability" is a substage of "kathodal hyperex- 

 citability," the latter being recognizable at the kathode by the appear- 

 ance of' closure tetanus (KCTe), or of an opening contraction (KOC) 

 with currents below five milliamperes in strength. 



Many careful studies of spasmophilia in children have been made with 

 the aid of this exact method of studying the electrical excitability of the 

 motor nerves. Thus, Gross's review of the work on spasmophilia, pub- 

 lished in 1911, reported forty-two important publications for the single 

 year. A careful study of spasmophilic children with the use of von 

 Pirquet' s methods and charts was made in the United States by Sedg- 

 wick and published in the St. Paul Medical Journal in 1912. The great 

 value of electrodiagnosis in childhood tetany is made clear also in the 

 paper of *T. B. Holmes (1916). In most pediatric clinics in America to- 

 day von Pirquet' s method, or some modification of it, is used for the 

 study of spasmophilia and allied conditions, and the attempt is being 

 made to decide whether all spasmophilia in children is true tetany (or 

 is related to it) or is to bo looked upon as a condition separable from 

 tetany. 



A peculiar electrical response observed in a single instance of tetany 

 by Bechterew should also bo mentioned before the topic of galvanic hyper- 

 excitability is dismissed. He designates it as an "excitation reaction" 

 (Erregungsreaktion) . The galvanic excitability of the motor nerves was 

 markedly increased in the case he studied, but the unusual consisted in the 

 fact that it increased even more when the electrical current was applied. 



