164 THE TREND OF THE RACE 



between a high birth rate and a high infantile death rate is not 

 simply a matter of cause and effect as so many of the Neo-Mal- 

 thusians assume. While large families may not be so adequately 

 supported on a small income as small ones, the association of high 

 birth rates and high infant death rates is to a large extent due to 

 the fact that both have a common cause in the lack of knowledge 

 or prudence in the parents. In families in which the number of 

 births is voluntarily limited, the death of a child is apt to be 

 followed by the birth of another to replace the loss, as is very 

 commonly the case in France. But even where there is no at- 

 tempt to regulate the propagation of the race there are certain 

 physiological factors which tend to bring about a correlation 

 between high infant mortality and a high birth rate. It is a 

 well-known fact that, while a child is nursing, the mother is much 

 less apt to conceive. Even primitive peoples often take advan- 

 tage of this fact and nurse their offspring for a long time in order 

 to avoid having others. The death of an infant and the conse- 

 quent interruption of lactation is commonly followed by another 

 conception. The more rapidly infants die the more rapidly, 

 therefore, new conceptions are apt to occur. 



The birth rate has fallen in several cities in Germany much 

 faster than the infant mortality. In Munich, for instance, the 

 birth rate fell from 1876-80 to 1906-09 over three times as much 

 as the infant mortality, and in 349 German cities of over 15,000 

 inhabitants the birth rate fell from 1901 to 1909 over three times 

 as much as the infant death rate. Mombert has pointed out that 

 in many cities and districts (Frankfurt, Stettin, Cologne, etc.) 

 in Germany the infant death rate has risen while the birth rate 

 has decreased, and in a few cities the birth rate has increased 

 while the infant death rate has decreased. 



France shows an unfortunate condition in having a low birth 

 rate and a high infant death rate. 



The classes in which the birth rate has fallen most are those in 

 which the habit of nursing offspring has most fallen into disuse. 

 The interruption of lactation would naturally tend to increase 

 fecundity, but it has not done this, largely, no doubt, because it 



