can be traversed by successive concentrated efforts, whilst the conscious difficulty experienced is largely increased.

The general theory of the rate of ideation, as investigated in the manner described, may therefore be stated thus:

(1) That the maximum rate of each human mind is constant, and may be conveniently stated in terms of its principal derived function, that of language.

(2) That the total possible amount of ideation in a given time cannot be increased by a division of the attention.

(3) That there is a specific retardation in the formation of ideas caused by the exercise of memory and proportional to its exercise. That this retardation can be accurately estimated when in its minimum phase, and at its maximum may be taken as equivalent to an approximate stoppage of constructive ideation.

It is now time to draw this paper to a close. The data which I have placed before you are too general in their nature to lead to anything like a complete quantitative theory of mind and its activities. But in this matter we have to glean our facts where we can; the field is wide and nearly untrodden, and there is scope for many workers before its scattered harvest can be gathered.

In trying to ascertain in a definite and measurable form something more of man's intellectual nature, we stand, as Commander Markham did upon that northern promontory, from which his eye wandered over the frozen and glittering waste which lay between him and the Pole. Like him, we shall realise by arduous experience, if we attempt to traverse it, that the palæocrystic sea of metaphysics will break down

This corroborates the view expressed by Hume in the following passage. "The mind, as well as the body, seems to be endowed with a certain precise degree of force and activity, which it never employs in one action but at the expense of all the rest."-Treatise on Human Nature, p. 325.

our efforts with no useful result. Theologians may undertake to balloon us over the icy wilderness; but, however lofty their method, they are at the mercy of airs and currents of the human atmosphere which it is impossible to control. With patient steps and slow, we must rather follow the devious coast line of solid experiment, convinced that we shall thus reach the nearest approximation to the knowledge we seek which the imperfection of our faculties will permit us to obtain.

ON THE JUSTIFIABILITY

OF SCIENTIFIC

EXPERIMENTS ON LIVING ANIMALS.

BY FREDERICK POLLARD, M.D. LOND.

THE Royal Society for the Prevention of Cruelty to Animals, whose persistent efforts to quicken the public conscience with regard to the infliction of thoughtless and wanton cruelty are worthy of all praise, began about the year 1873 to turn their attention to the subject of experimentation on animals for the purposes of scientific research, and from that time they have continued, in a fair and reasonable spirit, to protest against the abuses of vivisection, not seeking to entirely prohibit experimentation, but only desiring to prevent the infliction of excessive or unnecessary pain. As the result of a prosecution undertaken by this Society in 1874, a long discussion took place in the Times and the Spectator on the usefulness and justifiability of vivisection, a very prominent part against it being taken by Mr. R. H. Hutton, the able editor of the Spectator.

Very different was the character of the agitation commenced in 1875 by a Mr. George R. Jesse, of Macclesfield, and his friends, who styled themselves the "Society for the Abolition of Vivisection." This Society endeavoured in various ways to inflame the popular sentiment against physiologists. For instance, advertisements such as the following were day after day inserted in the Times and other papers, accompanied by the offer of a reward of twenty pounds for information leading to the detection and conviction before a magistrate of anyone engaged in the practice of vivisection:

"The hideous cruelty of dissecting living animals, and inflicting on them, though innocent and defenceless, multitudinous deaths of ex

cruciating and protracted agony, has secretly grown up in this nation, a nation which for ages past has been nobly distinguished by the courageous and unsanguinary character of its people. This moral ulcer has spread widely, and (whether it be or not a dreadful form of insanity) becomes dangerous and demoralising to society, a blot on civilisation, a stigma on Christianity. The public has little idea what the horrors of vivisection are; its crimes in studied, ingenious, refined, and appalling torture, in wantonness, uselessness, and wickedness, cannot be surpassed in the annals of the world!" and so on.

I may add that Mr. Jesse has always been so proud of this unique specimen of melodramatic writing, that he still has it reprinted, and will be glad to send a copy, with other choice samples of his composition, to anyone who will write to him for them.

About the same time, also, offensive caricatures, representing men of science, with fiendish delight depicted on their countenances, carving away at poor brutes, whose attitudes and expressions were indicative of acute suffering, were placarded about the London streets. Not long after, the services of that well-known guardian of public morality, the Illustrated Police News, were called into requisition, and its artist reproduced, with a view to the enlightenment of the provinces, one of the most startling of those placards with which the walls of London were adorned. The public interest having been thus in various ways aroused regarding vivisection, the subject was speedily brought under the notice of both Houses of Parliament; and in 1875 the Government decided to appoint a Royal Commission to inquire into the whole subject. The Commission consisted of the following gentlemen :-Viscount Cardwell (chairman), Lord Winmarleigh, Sir J. B. Karslake, Mr. W. E. Forster, Professor Huxley, Professor Erichsen, and Mr. R. H. Hutton.

The Commissioners held twenty-six sittings for receiving evidence, and examined fifty-three witnesses, including the