808 W. McKIM MARRIOTT 



is available. Howland a,nd Marriott (6) found, however, that when large 

 amounts of calcium salts, especially calcium chlorid, were given by mouth 

 an increase in the blood calcium resulted. When a sufficient amount of 

 calcium chlorid was given to infants suffering with tetany to increase the 

 blood calcium to an amount approximating the normal, the manifesta- 

 tions of tetany invariably disappeared. 



The reduction in the blood calcium in tetany is so constantly observed 

 and is so marked that it seems reasonable to assume that this lowering 

 of blood calcium is an important factor in the causation of the condition 

 of tetany. Additional support for this belief has been afforded by the 

 fact that symptoms of tetany develop when the blood calcium is experi- 

 mentally diminished by the injection of phosphates (Binger) or oxalates 

 (Neurath, MacCallum and Vogel). In severe nephritis accompanied by 

 phosphate retention in the blood and a consequent lowering of blood cal- 

 cium, manifestations of tetany are not infrequently observed. In para- 

 thyroidectomized dogs the development of tetany is coincident with a 

 fall in the blood calcium (MaoCallum and Voegtlein). 



The metabolism of calcium and of magnesium is so similar that one 

 might expect a disturbance in the magnesium metabolism in tetany. There 

 is very little data on this point. Howland and Marriott(&) found the 

 magnesium content of the serum to be normal in a number of infants suf- 

 fering from active tetany and this suggested that the magnesium metab- 

 olism is probably not affected. 



The metabolism of the alkali metals sodium and potassium has not 

 been as thoroughly investigated as that of calcium. There is a certain 

 amount of indirect evidence that alterations in the metabolism of sodium 

 and potassium may occur in infantile tetany. Aschenheim suggested 

 that the alterations in the irritability of the nervous system observed in 

 infantile tetany might be due to the disturbance in the relative amounts 

 of alkali and alkali earth salts present in the tissues. He based this 

 hypothesis on the now well known fact that nerve muscle irritability is 

 increased by the action of sodium and potassium salts and decreased by 

 the action of calcium and magnesium salts. According to Aschenheim's 

 hypothesis, tetany could be caused either by a decrease in calcium and 

 magnesium salts in the tissues or to an increase in sodium and potassium 

 salts. Aschenheim was able to demonstrate an increase in the sodium 

 and potassium salts in the brains of infants dying with tetany as well 

 as a decrease in the amount of calcium salts. Zeibel, Rosenstern and 

 Grulee noted an increase in the manifestations of tetany after the admin- 

 istration of sodium or potassium salts by mouth. It is a matter of clin- 

 ical experience that symptoms of tetany may develop after the adminis- 

 tration of large doses of sodium bicarbonate, especially to infants suf- 

 fering from severe acidosis. As the manifestations of tetany may appear 

 even before the acidosis has been corrected, it would seem that the ex- 



