EDUARD UHLENHUTH 321 



present experiments seem to prove, first, that the tetany-producing 

 substance causes permanent lesions of the nervous system, which lead 

 to permanent spasmodic contractions and paralysis of the muscle 

 even in the absence of tetanic convulsions, and second, that these 

 cannot be prevented by either Ca or Mg. For the most part they 

 result in an early death of the animals no matter whether or not Ca 

 or Mg has been applied. 



In connection with this fact we wish to mention Biedl's claim* 

 that no one has yet succeeded in prolonging the life of parathyroid- 

 ectomized animals by the application of Ca. From MacCallum's 

 paper, on account of the lack of controls, it cannot be seen whether 

 his parathyroidectomized dogs lived longer with Ca treatment than 

 without. 



That in spontaneous tetany Ca treatment may effect a cure, as is 

 evident from the report by Rowland and Marriott, does not prove 

 that in this case Ca has inhibited tetany as a disease. In spontaneous 

 tetany the period of the action of the tetany-producing substance 

 may be a very short one and the mere prevention of the tetanic con- 

 vulsions may keep the patient alive until normal function of the 

 glands involved has been restored. Th^ pathological changes which 

 the central nervous system undergoes in this short period may not be 

 severe enough to endanger the life of the patient after the cessation 

 of the action of the tetany toxin. 



In the light of the facts presented our experiments lead to the 

 following conclusions: 



1. The thymus gland excretes a tetany-producing substance which 

 in the normal animal is antagonized in an unknown way by the 

 parathyroids. 



2. In animals devoid of parathyroids (salamander larvae, para- 

 thyroidectomized mammals) this substance may, according to Mac- 

 Callum, reduce the Ca content of the organism; but by far the most 

 dangerous and important quahty of this substance is its highly in- 

 jurious effect upon the central nervous system, which causes perma- 

 nent spasmodic contractions of the muscles and paralysis of almost the 

 entire muscular system. 



3. It is possible to prevent the muscular contractions by introduc- 

 ing Ca salts into the body, though this can be done more effectively 

 by means of Mg salts. 



