802 THE ENDOCRINE ORGANS, OR DUCTLESS GLANDS 



those described above as appearing in laboratory animals, with the dif- 

 ference that the clonic movements and the extensor spasm are more or less 

 replaced by a tonic spasm of the flexor muscles, which produces charac- 

 teristic attitudes of the hands and feet. Associated witn the carpopedal 

 spasm generalized convulsions or laryngismus stridulus may occur. Laryn- 

 geal spasm may, indeed, be the sole manifestation of parathyroid de- 

 ficiency and it is also believed that many cases of convulsions occurring 

 in young children really depend upon a deranged function of these glands. 

 In brief, tetany, infantile convulsions, and laryngismus stridulus are proba- 

 bly but different manifestations of the same condition. 



It has been suggested that certain obscure nervous diseases of adults 

 such as paralysis agitans and Thomsen's disease are dependent upon 

 lesions of the parathyroids. Chorea, epilepsy, and eclampsia likewise have 

 been ascribed to disease of these bodies, but no cogent evidence has been 

 adduced to connect the parathyroids with any of these conditions. That, 

 on the other hand, the belief in the association of idiopathic tetany and 

 parathyroid disease is well founded is evMenced by the close resemblance 

 between the nervous symptoms of the two conditions. In the case of 

 monkeys especially, are the symptoms of the experimental condition often 

 strikingly similar to those of the idiopathic disease. In these animals 

 the muscular spasms following parathyroidectomy may imitate almost 

 unerringly those of infantile tetany, so that the tonic flexor spasms pro- 

 ducing the characteristic carpopedal attitudes of the idiopathic condi- 

 tion, appear, 



With regard to the culture of the disturbances set up by parathyroid de- 

 ficiency. Noel Paton, Findlay and Watson 45 have recently shown that the 

 clonic spasms are not primarily dependent upon the cerebrum or cere- 

 bellum, since they persist after ablation of these parts of the nervous 

 system ; in fact, removal of the hemispheres or suppression of their usual 

 functions by light anesthesia increases the severity of the clonus. This 

 does not imply that secondary involvement of the cerebrum may not 

 occur; on the contrary, the epileptiform convulsions, observed in the se- 

 verer types of tetany, indicate considerable cerebral mischief. Division 

 of the cord does not remove the spasms below the site of section, nor 

 has severance of the posterior roots any influence upon them ; but they 

 disappear after division of the anterior roots. These observations show 

 that the seat of origin of the spasms cannot lie in the peripheral nerves 

 or in the muscles. This leaves the efferent neuron of the spinal arc as the 

 affected structure. 



The other nervous disturbance following parathyroidectomy, namely, 

 tonic spasm of the extensor muscles has been shown to depend upon the 

 cerebellar arc. The hypertonus is uninfluenced by decerebration, whereas 

 the removal of cerebellar impulses by severance of the spinal cord abol- 



