204 THE DISEASES OF THE PARATHYROID GLANDS 



saw in the paralyzed extremities, in certain cases, in cats and dogs, after 

 complete section of the spinal cord, the occurrence of most intense spasms 

 in the paralyzed extremities in the acute attack. Moreover, the occurrence 

 of such spasms was not at all necessary. The exact demonstration of the 

 galvanic hyperexcitability of the nerves of the posterior extremities, which 

 develop even when the transection of the spinal cord has been done at the 

 same time with the extirpation of the parathyroids, shows with certainty 

 that the cause of the tetanic changes lies in the ganglion-cells of the spinal cord, 

 and not, as MacCallum and Biedl believe, in the higher centers. By this we do 

 not mean to assert that in tetany the higher centers do not likewise share in 

 the condition of hyperexcitability, and that the course of the twitchings in 

 the tetanic attack may not under circumstances be concomitantly influenced 

 by the centers that lie higher. 



Just as the motor nerves maintain their hyperexcitability, we may 

 assume that the same is true of the sensory and vegetative nerves. It 

 is very probable that the neurons of different orders become involved in a 

 definite sequence. In the slight grades of human tetany it is especially the 

 neurons of the first order that are affected. Here the occurrence of, as a rule, 

 bilateral spasms, convulsions, and pains, points to the spinal cord or to the 

 medulla oblongata as the seat of the affection. In the acute stage the vege- 

 tative nervous system is also affected concomitantly. In the severe cases 

 phenomena tend to occur that point to involvement of still higher centers. 

 Forced movements point to the mid-brain, disturbances of equilibrium to 

 the cerebellum, epileptiform convulsions to participation of the motor 

 cortical areas, and psychoses that of the cortex in general. A similar train 

 of thought was followed by de Quervain in 1893, and later by Ast, and others. 

 In children we actually find a mounting from cord to cerebrum, with in- 

 creasing intensity. Here, as Escherich emphasizes, the higher centers are 

 more frequently and more strongly involved. The retrogression of the 

 condition tends to follow a reversed series of involvements. 



Here I quote verbatim the conclusions arrived at in the work of Kahn 

 and myself. "In tetany there exists an abnormal irritability of the motor, 

 sensory, special sensory, and vegetative ganglion-cells that from here as a 

 starting-point involves the entire neuron. It is principally the peripheral 

 neurons that are found in this state of hyperirritability. Neurons of higher 

 orders may, however, be concomitantly involved. This abnormal state 

 expresses itself chiefly in a heightened excitability to mechanical, electrical, 

 or chemical irritants (latent tetany). Nevertheless the abnormal tension 

 in the ganglion-cell, either per se or through any other occasioning factor, 

 may lead to a heightened irritability in the organs supplied by it, and may 

 become manifest in tonic spasms and fibrillary twitchings of the trans- 

 versely striated muscles, in paresthesias, in tonic contractures of the smooth 

 muscles, in heightened secretional processes, etc. 



