807 



is the case. The removal of the parathyroid glands leads to a condition 

 which, if not identical, is very similar to infantile tetany in practically 

 every respect. The parathyroid glands of infants dying with tetany 

 may show anatomical changes (Yanase). The findings of Yanase have 

 failed of general confirmation. Bliss and also Auerbach found changes 

 similar to those described by Yanase in the parathyroid glands of chil- 

 dren who had no manifestations of tetany. (For literature on parathyroid 

 glands in relation to tetany see Aschenheim.) As yet no single dietary 

 factor has been brought into relationship to the condition of infantile 

 tetany. The fact that the disease is more active at certain periods of the 

 year and is more frequent in artificially fed infants than in those nursed 

 at the breast suggests the possibility of a dietary factor. The condition 

 is frequently but not always associated with rickets in the same individual 

 and this suggests that there may be a common etiological factor or that 

 the two conditions may be manifestations of a single basic disorder. As 

 against this view may be cited the fact that many infants suffering from 

 the most extreme degree of rickets have no evidences of tetany either latent 

 or otherwise and that infants with active tetany may have no demonstrable 

 signs of rickets. 



In tetany there are marked and characteristic alterations in the metab- 

 olism although the underlying cause of these alterations is not clear. 

 The most important changes are those taking place in the mineral metab- 

 olism especially that of calcium. 



During active tetany there is usually observed a decreased calcium 

 retention (Cybulski, Schabad(a), Orgler). During convalescence the cal- 

 cium retention is improved. 



Failure to retain a normal amount of calcium should result in a cal- 

 cium deficit in the body, and this has been found to be the case. The 

 calcium content of the brains of infants dying with tetany has been 

 found to be low by most investigators. (Aschenheim.) 



It is in the blood that the most marked alterations in the calcium con- 

 tent have been observed. Several authors have reported a low blood cal- 

 cium content in individual instances. Howland and Marriott (&) made a 

 study of a large number of cases of tetany and found a constant diminution 

 in the calcium of the blood serum. In tetany with active manifestations 

 they found the blood calcium invariably lower than in normal infants, 

 usually less than 6 mgm. per 100 c. c. (normal 10 to 12 mgm.). In some 

 instances the blood serum calcium was as low as 3 mgm. per 100 c. c. 

 With improvement of the clinical condition, the blood calcium invariably 

 increased. 



The lowered calcium content of the blood is not due to the lack of 

 calcium salts in the diet for it is often observed in the case of infants 

 receiving large amounts of cow's milk with its high calcium content. 

 There seems to be a failure of the body to absorb and retain such calcium as 



