THE THYROID APPARATUS 45 



animals is not invariably followed by symptoms of tetany, but 

 that these may be provoked by pregnancy or lactation. It appears 

 highly probable that in man also, parathyroid insufficiency may 

 be the originating cause of tetanic outbreaks, the determining 

 causes of which are metabolic changes arising from alteration 

 of function of the organs of generation. In the absence of any 

 definite anatomical information regarding this condition in man 

 it is impossible to be sure whether the assumed insufficiency of 

 these organs was pre-existent, or whether it occurs as the result 

 of changes in the female organism. 



Another form of tetany is that seen in infants, and here we 

 have definite anatomical grounds for associating it with the para- 

 thyroid glands. Erdheim found haemorrhages, or traces of 

 haemorrhages, together with blood pigment, in the parathyroid 

 tissues of children who had had tetany during life. Yanase, 

 working in Escherich's clinic, was able to demonstrate the pre- 

 sense of haemorrhages in the parathyroid glands of all children 

 under one year w r ho, during life, showed hypersensibility to 

 electric stimulus. After one year, he found traces of old haemor- 

 rhages or the finding was normal. Fleischmann found that the 

 teeth of all the persons he examined who had a history of infantile 

 tetany, showed hypoplasia of the enamel. Escherich concluded 

 from these results that all forms of infantile tetany are due to 

 parathyroid insufficiency. 



There are certain authors, however, who adopt a different 

 standpoint (Thiemich, 1906; Forsyth, 1908). They point to the 

 fact that the most diverse changes may be seen after death in 

 the parathyroid glands of persons who, during life, never showed 

 any symptom of tetany. But in these cases, it may very well 

 be that there was sufficient healthy parathyroid tissue to carry 

 on the function of the glands. Also, as Rudinger points out, 

 the cardinal symptoms of tetany are those which are latent ; they 

 may be supplemented by secondary convulsive symptoms, but 

 these are not an essential feature of the condition. And it is 

 just the latent signs which most easily escape observation. The 

 second point, namely, that cases occur where the clinical signs 

 are unmistakably those of tetany, while the post-mortem findings 

 are negative, loses its significance in face of the fact that a 

 transient tetany may be provoked in man, as in animals, by a 

 passing lesion of the parathyroid glands. 



The lack of anatomical material makes it difficult to discuss 

 the genesis of the other forms of tetany, namely, those of gastro- 

 intestinal origin, that which follows certain forms of poisoning, 

 and the tetany which is associated with some nervous diseases ; 

 but from what we know of analogous conditions in animals, it 

 seems highly probable that here also we have to do with in- 

 sufficiency of the parathyroid glands. 



Rudinger remarks the frequency with which the parathyroids 



