598 CHEMICAL PATHOLOGY OF THE DUCTLESS GLAXDS 



many investigators the acute manifestations of athyreosis, while the 

 more chronic changes of myxedema are attributed to the loss of the 

 thyroid. MacCallum's studies support this \dew, for he found the 

 results of parathyroidectomy in dogs very different from the results 

 of thyroidectomy. The most prominent symptoms are muscular 

 twitchings, gradually passing into tetanic spasms, and due to nervous 

 impulse rather than to muscular changes, since they did not appear 

 in muscles from which the nerve-supply has been cut off. Trismus, 

 protrusion of the eyes, and rapid respiration without cyanosis {i. e.. 

 air hunger) were also observed, and death usually resulted from ex- 

 haustion. Apparently these sj^mptoms are due to some toxic sub- 

 stance which, accumulates on account of the absence of the parathy- 

 roids, for it was found that simply diluting the dog's blood by with- 

 drawing part of it, and injecting a corresponding amount of salt so- 

 lution, caused a temporary cessation of the tetanic symptoms ; and 

 injections of emulsions of parathyroid checked the sj'mptoms for 

 some time, presumably through neutralizing the hypothetical poisons. 

 Degenerative changes that were observed in the cerebral ganglion- 

 cells also favor the view that some unneutralized toxin is responsible 

 for the symptoms following parathyroidectomy, and W. F. Koch *^^ 

 found that the urine of parathyroidectomized animals contains an 

 abundance of toxic bases, especially methyl cyanamide. On the other 

 hand, profound mental symptoms and insomnia have resulted from 

 feeding parathyroid to man.*^'' 



The metabolism after parathyroid ectomii may show tlie following ohaiities : -12 

 There is a reduction in the assimilation limit for carbohydrates (Hirsch, Under- 

 hill 42a and others). Concernino; inorganic metabolism there is disasjreement, for 

 while ilacCalliim and Voegtlin *^ found an increased elimination of calciinn and 

 a loss of tlie same element from the blood and brain (which they would make 

 responsible for the increased nervous irritability), Cooke found no such loss of 

 calciiun,^3a but she did find an increased urinary excretion of magnesiiun. Ac- 

 cording to most observers, nitrogenous metabolism is altered as shown by the in- 

 creased excretion of nitrogen, and especially of anunonia, which suggests tlie ex- 

 istence of an acidosis. Greenwald ** found increased anunonia less conspicuous 

 than increased undetermined nitrogen and sul])hur, and decreased ])hos])horus 

 excretion. There may occur an increase in the bases of the blo;id (alkalosis) 

 which disappears under the acidosis that results from tetany. ■♦^i> 



In view of the conflicting facts, the theory that the increased irritability and 

 spasm of tetany result from hyi)ocalcification of tlie nerve tissue is at present 

 unproved. Calcium does diminish nervous irrital)ility, as shown by J. Loeb, 

 and hence when administered it may favorably intlueiice the symptoms of tetany 

 para.tli\re()])riva., liut Ihis does not establish tlie tlieory. Tliat luunerous experi- 

 menters have been able to stop tliese symptoms, both in man antl animals, by 

 feeding of parathyroid,*5 or parathjroid nucleoprotein, establishes the relation- 



4ia.rour. Uiol. Chem., 11)1.3 (1,5). 4.3; Jour. Lab. Clin. :\led., lOK] (1), 2!1!). 



41b Morris, .lour. F.ab. Clin. Med., IDl.'i ( 1 ) , 2(i. 



■J 2 Sec review Ijv Cooke, .\mer. dour. :Med. Sci.. 1010 (UOi, 404. 



42a .Tour. Biol. Cliem., 1014 (IS), 87. 



43 Jour. K\p. Med., 1009 (11), 118; 101.3 (IS). CIS. 



43a See also IJergeim, Stewart and Hawk, Jour. Kxp. :Med., 1014 (20), 225. 



44Amer. Jour. I'liysiol., 1011 (2S), 10.3; Jour. Biol. Chem., 1013 (14), 3()3. 



44a Wilson, Stearns and 'i'hurlow, .lour. Biol. Chem.. I!)!') (23). SO, 123. 



45 See Ilalsted, Amer. .lour. ISied Sei., 1007 n34), 1. 



