

TETANY 197 



symptoms predominate, marked pigmentations progressing as far as bronzed 

 skin. 



Of greatest interest is the formation of cataracts. Already Meinert had 

 observed in tetany a case of cataract, and the first exact investigations began 

 with Peters. Important information was furnished by Erdheim, Pineles, 

 Zirm, Sperber, Bartels, v. Frankl-Hochwart, Schonborn, and others. The 

 cataract of tetany is characterized by its very rapid development. It is not 

 at all rare in children. It is especially frequent in the tetany of pregnancy, 

 and in women between the ages of eighteen and forty years, as observed by 

 Zirm and Sperber. In youthful individuals it occurs more frequently as nuclear 

 cataract, in older individuals as cortical cataract. Peters was the first to 

 show that the cataract formation was brought about by degenerative changes 

 in the ciliary epithelium. This caused a molecular concentration of the 

 ater in the chamber, thereby damaging the lens. Erdheim produced tetany 

 cataract by parathyroidectomy in rats. We are indebted to Pineles for the 

 information that the cataract formation occurs in all forms of tetany. 



Hanke on histological examination of the globe of the forty-nine-year-old 

 man who suffered with chronic tetany and cataract found optic neuritis and a 

 characteristic degeneration of the pigment epithelium of the posterior sur- 

 face of the iris, similar to that observed in diabetes mellitus. Pineles had 

 already attached theoretic value to the circumstance that cataract formation 

 could occur in tetany as well as in diabetes. 



Of recent date are the investigations concerning the disturbances in 

 tooth formation. Erdheim first observed that there occurred in rats, one and 

 one-half to two and one-half months after the operation, opaque spots on the 

 anterior surface of the incisor teeth which gradually advanced toward the 

 points with the teeth's growth. Either the tooth breaks off at this point or 

 the defect in the enamel heals, leaving behind a shallow groove. The tooth 

 may also break in the alveolus, in which case suppuration of the latter occurs. 

 Erdheim observed a deficient calcification of the dentine. Even the short 

 cessation of parathyroid function that occurs in autotransplantation of the 

 parathyroid is sufficient to determine the appearance of stripes poor in cal- 

 cium in the dentine of young rats. An especial clinical interest to Erdheim' s 

 studies is given by the investigations of Fleischmann. This worker held the 

 view that the defect of enamel so commonly observed was due, not as was 

 formerly supposed to rachitis, but to tetany. He points to the dispropor- 

 tion between the frequency of rachitis and hypoplasia of the enamel. In 

 rachitis are regularly found alterations in the dentine; in tetany, however, 

 one always finds hypoplasia of the enamel leading to the formation of hori- 

 zontal transverse surfaces. When frequent exacerbations of the tetany 

 have occurred, are found numerous furrows below one another. Fleisch- 

 mann investigated ten children who had suffered from tetany and found in 

 all the above-mentioned hypoplasia, and indeed this was present only on 



