THE INHERITANCE OF FAMILY TRAITS 159 



I 



■ 



Heavy ringed circles are normal females who transmit the trait. Lobsen, 

 1905. The details of Lossen's paper are translated in the "Treasury of Human 

 Inheritance," Parts V and VI, pp. 267-271. 



family histories of goitrous patients usually show a neuro- 

 pathic ancestry. A pedigree from Buschan is given in Fig. 

 138. 



c. Exophthalmic Goitre. — This peculiar condition is char- 

 acterized by an enlargement of the thyroid gland, protrusion 

 of the eyeballs, and extreme nervousness. It more commonly 

 affects women than men. Although, in the country as a 

 whole, it is not common yet it is more prevalent in some 

 districts than in others, doubtless owing to the interrelation- 

 ship of the members of the district with heavy incidence of 

 the disease. 



The disease is common in females; yet it is not inherited 

 strictly in sex-Hmited fashion. It is, however, clearly in- 

 herited; as certainly as epilepsy, with which it is not infre- 

 quently associated. Not many family pedigrees seem, how- 

 ever, to have been studied (Fig. 139). 



35. Diseases of the Vascular System 



This system consists, in the narrow sense, of the heart, 

 arteries and veins. Less is known about heredity of defects 

 and diseases of such an internal system because it is so in- 

 accessible to observation and study in the living person. 

 Nevertheless we shall see that "blood tells" in respect to 

 the traits of this set of organs. 



