78 INTERNAL SECRETION 



those of another group, which are also characterized by insufficient 

 sexual development and sometimes by mental deficiency. The 

 latter are recognized as more or less clearly defined clinical entities. 

 Of these the most important is true dwarfism, the nanismus, 

 microsomia, or nanosomia of Virchow. The pathological, as 

 distinguished from the ethnological, aspect of true dwarfism has 

 been minutely studied by A. Paltauf. D. v. Hansemann dis- 

 tinguished between two distinct forms of nanosomia. In the one, 

 the individual at some stage of his development ceases to grow 

 (nanosomia infantilis) ; in the other, the lack of size may be 

 traced back to the earliest beginnings of foetal life (nanosomia 

 primordialis). Individuals belonging to the latter group are very 

 small when born and remain, through life, smaller than normal 

 individuals of the same age, but they attain to a definite comple- 

 tion of their development. The epiphysial cartilages ossify, 

 sexual maturity supervenes, and the characteristic signs of in- 

 fantilism are absent. In infantile nanosomia, on the contrary, 

 the individual is normal in size when born, but at some point 

 in his history he ceases to grow. This cessation takes place 

 gradually and in spite of the fact that the epiphysial synarthroses 

 remain unclosed during life (Schaafhausen, Joachimsthal). 

 But here also, the proportions of the body are maintained and 

 the mental development is usually normal. Bayon describes these 

 individuals as having the appearance of normal people when seen 

 through the wrong end of an opera-glass. It is possible to 

 mistake true drawfism for infantilism in those cases only where 

 there is idiocy combined with anomalous formation of the bones, 

 probably the result of rickets, though the latter condition is rare. 



Achondroplasia (chondrodystropliia liyperplastica fostalis, 

 rachitis fcetalis, micromelia after Kassowitz) also presents cer- 

 tain clinical signs which resemble those of infantile myxcedema. 

 Achondroplasia presents no mental symptoms, however, and is 

 characterized by a lack of proportion between the shortness of 

 the extremities and the extreme length of the head and trunk, 

 which sufficiently distinguishes it as a distinct clinical type. The 

 condition represents an arrest of the processes of longitudinal 

 growth, caused by the absence, at the points of apposition, of 

 the vertical cell groups of the cartilages of the long bones. 



The differential diagnosis between sporadic myxcedema and 

 so-called mongolism is a more difficult matter. Mongolism is an 

 arrest of the natural processes of longitudinal growth, accompanied 

 by abnormality of the structure of the skull ; depression of the 

 bridge of the nose; open fontanelles ; thickened tongue; defective 

 development of the sexual organs; and especially mental derange- 

 ment, which at first takes the form of apathy and somnolence, 

 and finally passes into insane desire for movement. According 

 to Kassowitz, mongolism is distinguished from infantile myx- 

 cedema by the absence of myxcedematous cuticular changes, by 



