COPULATION, RELATIVE AGE 201 



ATAVISM 



Atavism is the recurrence, or tendency to recur, to 

 an ancestral type, peculiarity, or disease after its disap- 

 pearance for one or more generations. It is intermittent 

 heredity; reversion; "dating back." 



The offspring may be affected by physical conditions 

 of parents at the time of copulation, and also by the 

 condition of the parent during pregnancy. It is believed 

 that the first fruitful connection may sometimes have a 

 marked influence on subsequent offspring. It is con- 

 tended by a few that, if a full-blooded animal has been 

 fruitful by reason of connection with a mongrel, there- 

 after the blood of the dam is vitiated and she becomes 

 incapable of producing full -blood offspring when 

 united with a full -blood male of her own breed. 



The relative age and vigor of parents may have a 

 marked influence on the offspring. Animals which are 

 overfat tend to lose somewhat the power of transmit- 

 ting their highly specialized qualities and full vigor. In 

 fact, animals overfat may be said to be on the verge of 

 disease. Exercise, or the lack of it, in the parents may 

 be a potent factor for good or evil, in reproduction. 



In highly organized animals, mental impressions at 

 time of copulation, and for some time afterwards, may 

 have a marked influence on the offspring. In most 

 cases, however, mental impressions play little or no part 

 in the breeding of domestic animals. 



