84 BOAED OF AGRICULTURE. 



guish him from the animal have a most powerful influence upon 

 this law of inheritance. 



The second difference is the marriage institution, and, with- 

 out resorting to revelation at all for a divine sanction of this 

 institution, we believe its necessity can be proved upon physi- 

 ological laws alone, — that the health, happiness and highest 

 welfare of the race requires just such an institution ; in fact, 

 that the human species as a whole cannot be perpetuated in its 

 highest type without the marriage relation, and that the law 

 of inheritance must act in harmony with its sanctions. 



The third distinction is in the objects of creation. Man is 

 a free moral agent, accountable directly to his creator for all 

 his powers and his acts ; but the animal was created with a 

 very different nature, and for difierent purposes. The laws 

 that govern his organization can be more easily applied and 

 directed, especially by human agency. They are not only 

 more simple and less complicated, but can be brought to bear 

 more directly and with more immediate results. This law of 

 heritage is here in a great measure, not only uiKler the control 

 of human agency, but what may be called the physiological 

 influence is small compared with what it is in the human 

 species ; and then the external agents, such as food, climate 

 and exercise, can here be directed and applied far more aptly 

 and successfully. 



Without pursuing the subject farther in its relations to the 

 human species, we proceed at once .to examine what evidence 

 and illustrations of the reality of the law can*be deduced from 

 the animal kingdom ; or, in other words, explain what consti- 

 tutes hereditary influence in the improvement of stock, pre- 

 misinsr that the same class of facts and ars-uments that show 

 improvement here, afibrds evidence that similar laws appertain 

 also to human physiology. 



In changing or modifying the results of hereditary influence, 

 there are three great agents which claim a passing notice, — 

 they are climate, food and exercise. These agents, though slow 

 in their operation, have a powerful influence in changing phys- 

 ical organization. They may act separately' or all combined. 

 By climate we understand the changes in the weather, and the 

 temperature and purity of the atmosphere. Some animals in 

 their very nature are adapted to one climate, and others to a 



