It is a short-sighted and hopeless attempt to do violence to Nature in a search for scientific truth. Distinction must be made between the possible and impossible in the conditions under which we are placed in life. Thus, we cannot destroy the family relation, but we can make it happy and conducive to the welfare of the race. We cannot change the method of human generation, but we can spiritualize its exercise. We cannot destroy the instinct of private property, but we can guide and limit it. We cannot change structure, but we can educate it; nor abolish curiosity, but we can restrain and direct it; nor check invention, but it need not be applied to evil purposes. Neither can we make races equal, but we can establish justice and mercy in the relations of the stronger to the weaker. This study of the natural laws which necessarily limit rational human action applies with especial force to biological research, and explains the reason for limiting scientific method. Thus, the study of living creatures under unnatural or destructive conditions, although it may be a well-meaning attempt to acquire knowledge, is, nevertheless, a dangerous one. It is intellectually a false method which may lead to practical error, and produce a labyrinth of confusion and contradictory experience which hinders the attainment of exact knowledge. It is morally a false method, because it injures those elementary instincts of justice and mercy by whose evolution civilization advances. Thus the progress of the race is retarded. The present astounding multiplication of drugs, of inoculations, of mutilations in the practice of medicine, with the eager attempt to prove each new invention by a formidable array of imperfect statistics, is a striking object lesson in the present day of the error into which false methods of research have led many members of a noble and humane profession. It is a fallacy necessarily proceeding from a wrong view of what science really is. Although this erroneousness is by no means solely connected with vivisectional methods, yet if the high claim which the noble art of medicine makes to advance our social well-being be justly founded, a stringent obligation rests upon it not to injure the moral sense of its members by the methods employed in education or in practice. CHAPTER IX _The Axiom of Science_ The fundamental law, without whose observance reliable biological investigation is impossible, is stated as follows: ‘In studying the laws alike of organic and of inorganic Nature, the experimenter must be careful not to destroy the phenomenon that is being investigated.’