138 THE DISEASES OF THE THYROID GLAND 



observed perceptible mutism even after a period of observation lasting up 

 to two years. The question still needs careful study. 



In cases in which the power of hearing is markedly affected or is absent, the 

 development of speech is of course also slight; in the case mentioned, case X., 

 it was limited to a few inarticulate sounds. 



We know nothing as to the etiology of thyroaplasia and thyrohypoplasia. 

 Pineles states that there are sometimes malformations, tuberculosis, or alco- 

 holism in the ancestry, but this statement does not explain much. For in- 

 fantile myxedema, all those damaging influences come into consideration that 

 were set forth for myxedema adultorum. Worthy of note is the statement of 

 Spolverini, that sucklings who were nursed by women with goiter developed 

 myxedema. All of Spolverini' s observations, however, do not seem to me to be 

 free from objection. It seems well in this case for us to assume an expectant 

 attitude, until more observations have been made. The thyroid secretion 

 does not seem to go over in the milk, as according to many observations 

 (Lange and others) it was found that sucklings who were nursed by healthy 

 women, might yet develop myxedema. 



Differential Diagnosis. In the diagnosis of infantile myxedema all those 

 points are to be considered that were mentioned in the diagnosis of myxedema 

 adultorum. To these are added in infantile myxedema the ear marks of the 

 remaining behind in the physical and the mental development. Among 

 these the inhibition of ossification is especially important. Siegert is justified 

 in emphasizing this. One should not forget, however, that in many vegetative 

 disturbances, that have nothing to do with the thyroid gland, a delay in 

 ossification may exist. As far as it affects only the closure of the epiphyses, 

 as for instance in the case in eunuchoidism, it offers no difficulty from the 

 standpoint of differential diagnosis, as in infantile myxedema the delay in 

 growth and that in the occurrence of the bone nuclei is very evident. On the 

 contrary, there occurs in true infantilism and in hypophysial dwarfism an en- 

 tirely similar, although in most cases not such a severe, delay in ossification 

 as in infantile myxedema. It is true that growth in infantilism may some- 

 times be hastened through thyroid medication, but not in such a manner as 

 in sporadic cretinism. Hypophysial dwarfism tends to behave similarly (see 

 Chap. VI). In both conditions, moreover, the assimilation boundaries for 

 thyroidin lie essentially lower than in sporadic cretinism. 



The distinguishing of the etiologically different forms of cretinism in vivo 

 is often difficult, and in many cases quite impossible. Light cases, or those in 

 which the delay in development sets in at a later stage are to be counted as 

 infantile myxedema. In the severe cases that occur quite early the assump- 

 tion of a thyroaplasia is better warranted, but is not to be relied on in vivo, 

 as the negative finding on palpation is valueless. 



We shall consider in the third chapter the delimitation from endemic 

 cretinism. 



