to do but simply to make a mental image of it to themselves; had it been purely subjective, they might have had equal success, since they would have had nothing to do but look inwardly, and make a transcription of what they saw there; but because it required the conjoint action of the within and the without in a slow process of organic development, nothing less than the patient construction of a mental fabric, it was impossible the knowledge of it should come otherwise than by minute degrees and slowly accumulating increments through the ages. In any case it was not possible men should observe that which lay beyond the reach of sense; whether, for example, it was that the phenomena were outside the range of vision by reason of their immense distances, as it was with the heavenly bodies before the invention of the telescope, or equally inaccessible by reason of their exceeding smallness, as it was before the invention of the microscope with all that minute, subtile, and extremely active region of nature which that instrument has made known to us. How could they respond, by any fit movement, real in act or ideal in thought, to that with which sense could not come into any sort of direct and intimate relation? The establishment of a direct converse with new orders of facts and relations, by the artificial extension of the range and power of sense, was followed

soon in each case by a gradual modification of old notions, and by the gradual development of a new order of conceptions. Signally do the tedious growth and solid worth of real knowledge of nature through observation and experience contrast with the easy fecundity and ephemeral brilliance of imaginative theories concerning it.

Let us proceed now to inquire and consider what are the main and plain causes of imperfect and erroneous observation, and to summarize them briefly.

(a) The natural limitations or shortcomings of the

senses.

It is not defect of knowledge alone that has ensued from this obvious cause of inadequate observation; the defect has given rise to large and far-reaching positive error of thought as its natural consequence. Who can estimate the power and reach of erroneous belief which had its root in the exploded notion, so firmly held before the magnitude of the heavens was made known, that the earth was the centre of the universe ? How many wrong notions, how many fallacious theories, how many ignorant conceits, have flowed from the crude notion of matter, which, conceiving it as gross and inert, precluded the least conception of the nature and movements of its infinitely minute and active molecules? When it is said that matter cannot possibly think, how widely

different is the meaning which the proposition has in the mind of one who entertains the vulgar notion only of gross inert matter, and in that of one who is able, by means of adequate previous study, to conceive its infinitely active and subtile molecular energies, and realizes how its energies rise in concentrated intensity and dignity as it attains to higher and higher complexity of organization ! The medical science of the present day, in so far as it approaches exactness, is largely based upon the minute observation of phenomena in provinces of nature that were long inaccessible to human sense. Instead, therefore, of the demons which were once thought to be the causes of diseases, and to require to be exorcised, and instead of the almost equally imaginary vital spirits and humours which succeeded to the demons when they were discredited, the patient microscopist traces and makes known the life-histories of the minute organisms which he demonstrates to be the real causes of many diseases; and by taking scrupulous pains to keep wounds free from septic germs, or by exorcising antiseptically, so to speak, the germs that do get into them, the surgeon has discovered that he can prevent putrefaction, and so attempts and carries to a successful issue achievements of surgery not dreamt of in former ages. From fictions of imagination to facts of observation—

such has been the history of the coming into being and of the stable growth of medical knowledge, as of other natural knowledge; and such, without doubt, is the prospective path of progress in those nebulous regions of nature where the supernatural has not yet been resolved into positive knowledge. New developments of thought and new powers over nature have invariably followed the invention of instruments which carried the action of the senses into provinces hitherto impenetrable by them.

(b) Next in order to the want of means of observation is the want of opportunities of observation.

It is obvious that he who has not the opportunity is practically as ill placed for arriving at a sound conclusion as he who has not the means of observing ; to want the opportunity is to want the use of means. The miracle takes place easily when those who witness it are forbidden, either by external hindrance or by the sometimes stronger barrier of internal prohibitive scruple, to make a thorough and exact examination of all the circumstances attending its occurrence. It admits of no doubt, as Voltaire wittily remarked, that magic words are capable of destroying a whole flock of sheep if the incantation be accompanied with a sufficient dose of arsenic; and, after the event, there will be no doubt of the miracle in

the mind of the awe-stricken observer who has not seen more of the performance than the magic ceremonies. A person may rise from the grave after being buried for some days (as the Indian fakir does) when means are not scrupulously taken to ensure adequate observation that he is buried completely; and witnesses shall vouch solemnly that they have seen the thing happen whose sincerity as witnesses is as unquestionable as their incompetence as observers. A credible eye-witness in any such matter is a witness who is not only qualified by natural aptitude and acquired training to make the special observation, but who possesses the means, uses all the expedients, and exhausts the opportunities of investigation. Many miracles have taken place in times. past, as the miraculous liquefaction of the blood of St.

*

* A collection of cases of the kind, obtained directly from, and vouched for by, British officers who had been eye-witnesses of them, is given by Mr. Braid in his "Observations on Trance or Human Hybernation" (1850). In one case the man was buried for six weeks ; in another for ten days, the grave being strictly guarded. But the result is disastrous when the proper precautions are not taken to make the miracle a success. For example, a weaver, who undertook to remain buried during the whole period of the Mahometan fast, was dead when taken out. And a Mahometan priest, who, in order to increase his reputation for sanctity, dug for himself a small cave underground, into which he retired, the top of the cave being then covered with boards and earth, was taken out dead, although he had taken the proper precaution to put a hollow bamboo through the covering in order to prevent suffocation. (The Medical Jurisprudence of India, p. 656, by Dr. Norman Chevers.)