There is what is known as the "balance of natural forces." It is this that keeps the planets balanced in their orbits, and among animals it holds the species within the bounds which make for the greatest happiness of the greatest number. It is the plan of an all-merciful Creator, and man has never been able to suggest an improvement upon it, within the limits of physical conditions.
From the above, we see that every animal life is cast into the world as an experiment, often of the severest and most painful type. In this lifelong vivisection. Nature provides no ether or chloroform, nor even chloral or morphine.
By this very dispensation of Nature God clearly gives to man every sanction to cause any amount of physical pain which he may find expedient to unravel his laws. Not only this, the situation places upon man heavy duties, which he is bound to perform. These we will consider in a moment. As far as biological science is concerned the whole argument may be summed up as follows: Biology is not an exact science like mathematics and physics. These sciences are exact simply because it is possible in them to obtain as many equations as there are unknown quantities to be determined. Hence, with the solution of all possible equations, every unknown quantity in these sciences may be exactly determined. In biological sciences the case is thus far quite different. Here the unknown quantities are legion in every equation. Hence the extreme difficulty of any solid advance; hence the many mistakes, the many disagreements. In the best of experiments it is only possible to mass one series of unknown quantities against another series of unknown quantities so that they balance as nearly as possible, and then with our one unknown quantity, about which the experiment turns, make the best temporary solution of our problem possible. Thus the science must be content to proceed until the vast series of unknown conditions which influence life have been dealt with one by one. Thus, if the science is to advance, if we are ever to learn under what conditions life is most favorably placed, we must vary the conditions in every possible way—i. e., experiment physiologically; and, as we have seen, everything in the divine ordering of Nature is in complete harmony with this method, and bids man Godspeed in this great work.
Thus far we have considered Nature as uninfluenced by the presence of man. Let man, a moral being, take his place among the animal creation, and at once there spring up moral relations between him and every living thing capable of feeling pleasure and pain. It becomes his duty to do all in his power to increase the happiness and to diminish the suffering of every sentient thing. But we do not sympathize with the Hindu who lay down before the starving tigress in order to save her life and the life of