218 ILLUSTRATED STOCK DOCTOB. 



sperm-cell, but also in great measure upon the effect exerted upoii tk« 

 nervous system of the mother by him. Hence the preponderance ol 

 one or other of the parents will, in great measure, depend upon th» 

 greater or less strength of nervous system in each. No general law li 

 known by which this can be measured, nor is anything known of th« 

 laws which regulate the temperament, bodily or mental power, color oi 

 conformation of the resulting offspring. 



Acquired qualities are transmitted, whether they belong to the sire or 

 dam, and also both bodily and mental. As bad qualities are quite as 

 easily transmitted as good ones, if not more so, it is necessary to take 

 care that in selecting a male to improve the stock he be free from bad 

 points, as well as furnished with good ones. It is known by experienca 

 that the good or bad points of the progenitors of the sire or dam ari. 

 almost as likely to appear again in the offspring, as those of the imme- 

 diate parents in whom they are dormant. Hence, in breeding the rule is, 

 that like produces like, or the likeness of some ancestor. 



The purer or less mixed the breed, the more likely it is to be trarrs- 

 initted unaltered to the offspring. Hence, whichever parent is of the 

 purest blood will be generally more represented in the offspring ; but as 

 the male is usually more carefully selected, and of purer blood than the 

 female, it generally follows that he exerts more influence than she does ; 

 the reverse being the case when she is of more unmixed blood than 

 the sire. 



Breeding "in-and-in" is injurious to mankind, and has always been 

 forbidden by the Divine law, as well as by most human lawgivers. On 

 the other hand, it prevails extensively in a state of nature with all grega- 

 rious animals, among whom the strongest male retains his daughters and 

 granddaughters until deprived of his harem by younger and stronger 

 rivals. Hence, in those of our domestic animals which are naturally gre- 

 garious, it is reasonable to conclude that breeding "in-and-in" is not 

 prejudicial, because it is in conformity with their natural instincts, if not 

 carried farther by art, than nature teaches by her example. Now, in 

 nature we find about two consecutive crosses of the same blood is the 

 usual extent to which it is carried, as the life of the animal is the limit ; 

 And it is a remarkable fact that in practice a conclusion has been arrived 

 ftt, which exactly coincides with these natural laws. "Once in and once 

 out," is the rule for breeding given by Mr. Smith in his work on the 

 breeding for the turf ; but twice in will be found to be more in accord- 

 ance with the practice of our most successful breeders. 



The influence of the first impregnation seems to extend to the subse- 

 quent ones ; this has been proved by several experiments, and is espe- 

 eially marked in the equine genus. In the series of examples preserved 



