THE INHERITANCE OF FAMILY TRAITS 99 



to general paralysis of one or both sides and, in later develop- 

 ment, is associated with feeble-mindedness. Pedigrees arc 



given by Dercum (1897) Fig. 62, Pelizaeus 



(1885) Fig. 63, Freud (1893) and others. l^ji ji 



Since the tendency is carried by normal ^^^"^^ ^ 



persons and since (as in Freud's case) it is r~^ 



apt to occur with consanguineous marriage it ]^ ^jm 



is probably due to a specific defect. To „ fiq_Tii 



avoid the reproduction of the disease, mar- trates the pedigree 



riage with unrelated blood is essential. ?! ^ ™''" J:^^* "T 



'^ has cerebral di- 



e. Multiple or Disseminated Sclerosis. — plegia who married 

 This is a diffuse degenerative disease of the I "X" ^miia^ 

 spinal cord. It leads to tremors in the arms affected. Both 



J , 1 T J. 1 c 1 1 children are af- 



and trunk, disturbance of speech and even- fected. Pelizaeus 

 tual paralysis. It is usually not regarded as i^^- 

 hereditary but an interesting pedigree showing its appear- 

 ance in 3 generations has been investigated by Merzbacher 

 (1909), Fig. 64. 



As the pedigi'ee table shows, the disease is transmitted 

 through unaffected females. The eugenic conclusion is, 

 consequently, that even unaffected females who have af- 

 fected brothers should not have children. 



f. Hereditary Ataxy (Friedrich's disease). — This disease 

 causes a slowly but surely progressive loss of directed move- 

 ments, first of the legs and then of the arms; speech becomes 

 elusive and indistinct; scoliosis (curvature of the spine) 

 may appear and the feet become drawn up. These symp- 

 toms accompany a degeneration in the upper part of the 

 spinal cord. 



he had only normal children, but by the third (to a normal woman who had 

 a first cousin, II, 5, with cerebral diplegia) he had 4 sons of whom 3 wore 

 affected with this disease. The eldest, III, 3, was normal until 10 niontlis old, 

 then had general convulsions, after which spastic symptoms gradually ap- 

 peared, becoming pronounced later. Now he can walk only a few steps 

 and is quite idiotic. The third son was normal until 2 years old, but is now 

 deteriorating after an attack of measles and the youngest, only 2 years old, 

 has just become diplegic and epileptic. Dercum, 1897. 



