THE STUDY OF AMERICAN FAMILIES 247 



book of Human Anatomy must be rewritten for the Chi- 

 nese, for the Ethiopians, and for the Eskimos, so must it 

 be rewritten for the Rumanian, for the North ItaUan, for 

 the Norwegian and for the Spaniard. Nor will the same 

 description of structure of the human body serve, in all 

 details, for the Lees of Virginia, the Ishmaelites of Indiana 

 and the Edwards family of New England. Similarly the 

 text-books of pathology are not universally applicable. 

 There are hundreds of diseases Hsted that you and I could 

 no more have than we could have extra fingers or a retina 

 without pigment. Even the symptoms of a disease will 

 differ in different strains; for the symptoms of a disease 

 like typhoid fever are not due only to the typhoid germ 

 but to the reaction of the particular Uving body to those 

 germs. In not a few cases the prognosis, or prospect of the 

 course of the disease, should read: The prognosis can be got 

 by asking the head of the family *' What is the usual course 

 of the disease in this family?" Indeed, the classification 

 and diagnosis of a disease is often got better by a com- 

 parison of the brother and sister of the patient than by 

 reference to a book of symptoms. "I knew a family of 

 four sisters," said Dr. E. E. Southard to me, '^three of 

 whom had manic-depressive insanity; the fourth had a 

 mental disorder that had been classified quite otherwise 

 by another physician. But a comparison of the sisters 

 showed that the mental disorder was of the same type in 

 all." Bleeders in different families differ in the ease with 

 which hemorrhage is induced and the difficulty in stopping 

 it; and in the SulHvan County bleeders the disorder runs 

 a peculiar course so that they are called ''nine-day bleed- 

 ers." Of imbecility there are, as we have seen, all grades 

 and all usually incurable; but the great ''moron" or simple- 

 ton family of New Jersey is peculiar in that mental develop- 

 ment is not permauently arrested but only much retarded. 



