130 THE DOG IN HEALTH. 



a foetal in each of wliicli the structure is essentially simi- 

 lar, viz., blood-vessels covered with a layer of cells which 

 elaborate the material from the mother's blood and fit it 

 for the nourishment of the young animal, and which also 

 excrete into the mother's blood the waste that has been 

 thrown into the blood of the foetus by its own excretory 

 organs. 



It is highly important to understand clearly the nature 

 of impregnation and the relation of the mother and foetus 

 in utero. 



From these relations we think the following principles 

 must of necessity follow : 



1. The offspring must be in some degree a compound 

 of the nature of both parents, but not equally in most 

 cases. Some stud dogs are " prepotent," or have an un- 

 usual power in imparting their own nature to their off- 

 spring. The same applies to some bitches. 



It is also evident that all in the same litter may not 

 equally represent both parents. It would be strange if it 

 were so, as the actual influence of the male cells may not 

 be equal on each ovum or all male cells may not be equally 

 potent. In fact, there is of necessity great room for all 

 sorts of variations in such matters, so that all rigid dicta 

 as to which parent exercises the most influence on the 

 offspring are out of place. 



2. The dam, from her long connection with the foetus, 

 must exercise an influence peculiarly her own. Since her 

 health, her temper, her occupation, etc., all have an influ- 

 ence on her own nutrition and that of her offspring, it is 

 of the highest importance that the brood bitch should be 

 given the greatest care. 



