448 NELSON W. JANNEY 



it is well to remember that the lowered resistance of the goitrous individual 

 invites readv attack by bacterial and other toxic agents, so that chronic 

 infections and intoxications are probably to be best regarded in many cases 

 as accompanying phenomena as well as causative factors in the production 

 of cretinic degeneration in the offspring. Be this as it may, statistics have 

 definitely established an etiologic relationship between goiter in the 

 parents and cretinism in the offspring. Later researches have demon- 

 strated the low iodin content of goiters, therefore their low hormone con- 

 tent and probable sub-functional condition of such thyroid glands. It 

 would seem therefore that the development of congenital goiter may be 

 compensatory as well as possibly due to hereditary lack of normality in the 

 thyroid apparatus of the child. These factors are apparent from Horse- 

 ley's experiments in which goitrous puppies were born to partially thy- 

 roidectomized bitches. 



Age. Endemic goiter may develop at any age, though its incidence is 

 least during the first years of life. Its incidence gradually increases to 

 the fourth decennium, then decreases. In spite of statements to the con- 

 trary of Kocher and other Swiss writers, it has been demonstrated statisti- 

 cally that endemic goiter is much more frequent among adults than chil- 

 dren in about the proportion of 2:1 (Bircher, Baillarger). It is less 

 common before puberty. Most authors agree that endemic cretinism re- 

 quires a certain length of exposure in an endemic community for its 

 development as Wieland carefully emphasizes. It thus differs from spo- 

 radic athyreosis and congenital hypothyroidism which can often be de- 

 tected in the first months of the life (E. Wieland). The age of predilection 

 in the later years of childhood is from the 7th to the 10th year. The 

 incidentality then slightly diminishes to rise again at puberty. Children 

 are apparently more frequently affected in beginning epidemics than 

 adults. In a goiter epidemic in a village of 1,500 inhabitants, of the 31 

 cases affected, 29 were under sixteen years of age (McCarrison). Endemic 

 goiter and cretinism are rare among old people who have not developed 

 the disease previously. 



Hex. During childhood the incidence of endemic goiter is about equal 

 among boys and girls. From puberty onward, the female sex is most often 

 affected, the ratio being stated from 2 :1 to 6 or 8:1 by various statis- 

 ticians. Puberty and gestation predispose to goiter. During pregnancy 

 goiters may greatly enlarge, declining again in size thereafter. Pregnancy 

 in normal women is, however, known to cause thyroid hypertrophy in a 

 number of cases. Even menstruation may cause thyroid swelling. The 

 sex incidence is much influenced by the severity of the endemic. In lightly 

 affected communities women are more susceptible. When the disease is 

 very severe, both sexes may be equally attacked. 



Race. All races, Caucasian, Mongolian, Malayan and Negro, may be 

 affected. The apparent greater incidence at times noted among 



