SUTHERLAND SIMPSON 



tremors and convulsions produced by the injection of ammonium carbo- 

 nate persist jvhen the animal is fully anesthetized, whereas the convul- 

 sions in parathyroidectomy are suppressed by full anesthesia, as was shown 

 by Paton and Findlay. 



Voegtlin and MacCallum noted in incipient parathyroid tetany that 

 the peripheral excitability was increased and that the intravenous injec- 

 tion of ammonium salts had a preventive effect, rather than otherwise. 



Wilson, Stearns, and Thurlow consider that deranged metabolism, 

 whereby the normal equilibrium of acids and bases in the blood is dis- 

 turbed, is the cause of the symptoms of parathyroid tetany. After para- 

 thyroidectomy, before any symptoms appear, a condition of alkalosis may 

 develop, but when the active muscular contractions of tetany begin, this 

 alkalosis is obviated by the acid products, so that, after periods of acute 

 tetany, a condition of acidosis may result. Wilson, Stearns, and Janney 

 showed that the increased excretion of ammonia only begins after the 

 muscular action is in evidence, and is produced probably to neutralize 

 the acidosis which results. 



Togawa found a condition of acidosis in dogs suffering from para- 

 thyroid tetany, and the antitryptic and non-protein nitrogen content of 

 the serum were usually increased. In thyroidectomized dogs, with no 

 tetanic symptoms, acidosis is never observed, but sometimes a slight alka- 

 losis is present. 



On the whole, the evidence in favor of ammonia as the exciting agent 

 is unsatisfactory. There are many essential points in which the symp- 

 toms of intravenous injection of ammonia differ from those of parathy- 

 roidectomy. 



Xantliin as the Toxic Agent. With regard to xanthin, this, in the 

 hands of Berkeley and Beebe (a), produced effects which were allayed by 

 calcium and strontium, but Voegtlin and MacCallum failed to confirm 

 the observation. 



Ilistamin as the Toxic Agent. (3-iminazolylethylamin has also been 

 suggested by Biedl, on account of its relation to ergot, but Dale 

 and Laidlaw, who investigated the action of this substance, find that it 

 affects mainly visceral muscle; striated muscles, which are notably in- 

 volved in parathyroid tetany, hardly at all. 



Guanidin and Methytguanidin as the Toxic Agents. Koch (a) (b) 

 in 11)12 and again in 1913 reported the discovery of methylguanidin in 

 considerable quantity in the urine of parathyroidectomized dogs suffering 

 from tetany. In a series of important papers published in 1917 Paton 

 and his pupils have brought forward many strong arguments in favor 

 of these substances as the toxin or toxins which are the exciting agents 

 in parathyroid tetany. The literature of previous work on the action of 

 ffuanidin is given i n the communication by Paton and Findlay (c) (1916) 

 presenting the results of their own contributions to the subject. 



