The various ethical dangers resulting from conscienceless or irrational experiments on animals demand much more serious consideration by the profession than has hitherto been given to them. In the opinion of an increasing number of intelligent physicians, a vast amount of what is now presumptuously called research--experiments disguised under learned names, but which are really the irrational mutilating and diseasing of sentient living creatures--are no more _scientific_ research than is the gratification of a child’s curiosity when it sticks a pin with a thread through a cockchafer, to see how long it will fly and how loud it will buzz. The child, when punished for its thoughtless cruelty, might remonstrate in learned terms that it should not be restrained, for it was investigating the vital endurance of the _Melolontha vulgaris_ and the acoustic properties of its wing-covers, under interesting and abnormal conditions. A large proportion of what is simply conscienceless curiosity, often starting from more or less frivolous tentative diversions of the laboratory, though now by courtesy named research, is no more valuable than the child’s spinning of the cockchafer, and should be as sharply checked. The genesis of discovery in biology, with its necessary relations to therapeutics, has yet to be written. Extending experience is more and more clearly showing us, as a practical fact, that whilst observation and rational--_i.e._, humanely limited--experiment are legitimate and noble efforts for the attainment of improved medicine, cruel and merely curious experiment, condemned by our moral faculties, are misleading and mischievous. Men like Professor Henschel, of Upsala, and Professor Pettenkofer, of Munich, warn our eager young investigators against drawing conclusions as to human beings from experiments made on animals. We find, as a matter of fact, that all the _permanent_ advances of medicine have been gained whilst pursuing rational and righteous methods, whilst all the fiascoes of supposed discovery have resulted through departing from them. Anæsthetics, antiseptics, and sanitation are not the result of cruel experimentation. _Danger of Inoculation._--The most serious fallacy arising from erroneous methods of biological research is the practice of vitiating human blood by the introduction of the diseased products of animals. This dangerous method, which threatens to undermine national health, is the necessary outcome of diseasing animals on the plea of seeking remedies for human disease. The intellectual fallacy involved in this practice will be considered later; but its ethical character as affecting conscience must here be noted, as it is this line of research which is productive of the most extended form of cruelty to the lower animals--viz., _slow_ torture.