THEORY OF GENERATION. 101 



yet if the semen reaches the uterus first, it will still cause a fruit- 

 ful impregnation, because it remains there (or in the fallopian 

 tubes) uninjured until the descent of the ovum. 



11. THE INFLUENCE OF THE MALE upon the embryo is partly 

 dependent upon the fact, that he furnishes a portion of its sub- 

 stance in the. shape of the sperm-coll, but also in great measure 

 upon the effect exerted upon the nervous system of the mother by 

 him. Hence, the preponderance of one or other of the parents 

 will, in great measure, depend upon the greater or less strength of 

 nervous system in each. No general law is known by which this 

 can be measured, nor is anything known of the laws which regu- 

 late the temperament, bodily or mental power, color or conforma- 

 tion, of the resulting offspring. 



12. ACQUIRED QUALITIES are transmitted, whether they belong 

 to the sire or dam, and also both bodily and mental. As bad qua- 

 lities 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 is free from bad points, as well as furnished with good 

 ones. It is known by experience that the good or bad points of 

 the progenitors of the sire or dam are almost as likely to appear 

 again in the offspring as those of the immediate parents in whom 

 they are dormant. Hence, in breeding, the rule is, that like pro- 

 duces like, or the likeness of some ancestor. 



13. THE PURER OR LESS MIXED the breed the more likely it 

 is to be transmitted 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. 



14. BREEDING " IN-AND-IN" is injurious to mankind, and has 

 always been forbidden by the Divine law, as well as by most hu- 

 man lawgivers. On the other hand, it prevails extensively in a 

 state of nature with all gregarious animals (such as the hoise), 

 among whom the strongest male retains his daughters and grand- 

 daughters until deprived of his harem by younger and stronger 

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

 rally gregarious, it is reasonable to conclude that breeding u 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 at 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 



