HEREDITY AND MANIC-DEPRESSIVE PSYCHOSES 



335 



There remains the statistical method, which is applicable in either of two 

 ways. We may, by applying particular theories of heredity, group our 

 matings so as to compare the progeny with the expected theoretical propor- 



TABLE 1 



Number of siblings in families of patients with manic-depressive psychoses 



TABLE 2 

 Order of birth of patients with manic-depressive psychoses 



tions. This is, for example, the method of Mendelian analysis. Much 

 work has been done in this manner in the past two decades but it must be 

 admitted that the results are as yet inconclusive. This follows primarily 



