A History of the Inductive Sciences

edly possible, and restrain the indiscriminate mixture of elements,?remain to be discovered."f Since the researches of Faraday have proved the identity of chemical and electrical attraction, it would seem that the science of chemistry can scarcely be regarded as having a distinct existence, and that it must ultimately merge in those of electricity and dynamics, which are themselves probably to be included in a single general expression. In the sciences of Light and Heat, it is remarkable that the most recent discoveries, and the general views founded upon them, seem to do away altogether with the idea of these principles as distinct, imponderable, but material agents. With respect to light, indeed, the fundamental doctrines of the undulatory theory may now be regarded as fully established; and it is only in their application to an immense mass of phenomena that any delay can take place, owing to the laborious nature of the process, and the intricate mathematical reasoning required. The undulatory theory of heat is found capable of answering all obvious objections, and may be regarded as on its trial, to be confirmed or modified by future discoveries, and especially by an enlarged knowledge of the laws of the polarization of heat. The present condition of the science of Electricity is peculiarly interesting to the physiologist. The immense number of new and unexpected phenomena detected in recent times by the industry of experimental enquirers, have been made subservient to the discovery of general laws, which not only include the facts upon which they were founded, but others at first sight of an entirely different character. In this manner not only voltaic, atmospheric, and animal electricity have been proved to be but forms of common electricity; but. even magnetic phenomena appear to result from a peculiar application of the same powers, or, in other words, a peculiar manifestation of the same properties. Here, then, we have effects of a ? Whewell, vol. ii. p. 121. f Herschell's Preliminary Discourse, p. 306. 324 Wuewell's History of the Inductive Sciences. [April, most dissimilar character, occurring as the necessary results oi a common cause operating under a variety of conditions; and we cannot but hope that a corresponding simplification may, at some future time, be effected in physiological science, by the comprehension of those vital properties which are at present our ultimate facts (and whose laws cannot be said to be yet established,) under one general expression. Moreover, the progress of discovery in electrical science, and other allied branches, renders it probable that electricity is no longer to be regarded as a distinct, material, though imponderable, agent, but that it is rather to be looked on as a general property of matter, like attraction of other kinds; and that the actions which we witness, and the powers which are developed, are nothing more than the manifestation of this property, according to the conditions in which the material bodies concerned in them are placed. " It cannot be denied," says Mr. Whewell, " that the theory of the electric fluids affords a plausible explanation of facts; but it may fairly be questioned whether it is necessary, and the analogy of light and heat (and especially the polarization of the latter,) has done much to shake the theory of the electric fluids as a physical reality." The most beautiful generalization, however, of which this branch of science seems capable is that recently proposed by Mossoti, who has rendered it highly probable that the phenomena of statics and dynamics, with those of the molecular actions of bodies, and those of all the forms of electric power, may be included under the same general expression. If the views here stated as to the non-existence of a distinct electric fluid, and the possession of electric properties by all matter, should prove correct, we cannot but consider them as having a most important bearing on physiological speculation. Our analysis of the functions of living beings, or of those changes whose sum constitutes their life, terminates in referring them all to certain properties possessed by their component structures, excited to action by the relations in which they are placed to each other and to external agents. Some of these properties we know to be physical, since they are equally manifested by dead and living organized tissues; others are of a different character, being essentially vital, and necessarily implying the pre-existence of a living system, by which inorganic matter has undergone the process of organization, and in which alone these properties can be manifested. The existence of these vital properties must for the present be regarded as our ultimate facts in physiology; but we may reasonably enquire whence they are derived. It is commonly said that an organized body, in assimilating and organizing the nutrient matter, by which the changes necessary to its existence are maintained, communicates or superadds to it, at the same time, those vital properties of which it was itself previously possessed. A logical exception might be taken to this form of expression, since we can scarcely regard that as communicable which has not a distinct existence; and, if we understand the term property aright, it merely expresses the relation between matter, in some particular form or state, and the percipient mind. But, passing by this consideration, we may advantageously enquire into the analogy on which the view just stated has been often supported. There is no more difficulty, it has been argued, in conceiving how vital properties may be superadded to organized matter, than in understanding how magnetic properties may be communicated to iron : but the 1838.] Physiology an Inductive Science. 325 latter process appears to be really of a nature different from what is commonly supposed. The so-called communication of magnetic properties to iron is nothing more than the production of a change in the condition of the metal by which the electric properties, previously existing in that as in every form of matter, are manifested, and caused to give rise to magnetic powers. A little consideration will shew that we cannot become cognizant of any property of matter without some change being effected, either directly upon our organs of sense, or upon them through the medium of its action with some other material body. Every such change, therefore, requires certain conditions, without which the property cannot be manifested; and, until any form of matter has been placed in the conditions requisite to develope a particular property, we have no means of judging either of its presence or absence. It is perfectly correct to say that organized matter exhibits itself to the mind in a relation totally different from that of inorganic matter, and that properties apparently new are thereby manifested. But no one can assert that there does not exist, in every particle of matter, the capability of exhibiting vital actions, when placed in the requisite conditions; in other words, when made a part of a living system by the process of organization. It is only the complexity of the conditions required to manifest it which prevents our recognizing this capability as a common property of matter, or at least of those forms of it which we know by experience to enter into the composition of organized structures. Of all the branches of science whose phenomena are dependent upon simple physical principles, that of Meteorology is the most obscure and apparently uncertain. Although the changes which become the subjects of observation are constantly occurring under our notice, the difficulty of controlling and artificially combining the agents concerned in them prevents us from deriving much assistance from experiment; whilst the complexity of the conditions under which similar effects occur, and the variety of results which may arise from very slight modifications of the same cause, render such a mode of enquiry peculiarly necessary. When we turn from the inorganic world to contemplate the living kingdoms of nature, we at once perceive avast difference in the objects of our investigation; and we may perhaps be led to suppose that this change requires that our mode of philosophising should be varied in accordance with it. But a little reflection must convince us that if the inductive system be really founded upon the relation between the human mind and the world in which man is placed, it must be as applicable to the discovery of general laws in one department as in another; and that, although each of the different steps may be individually modified according to the character of the objects upon which our reasoning is founded, the general plan of the whole must be the same, in whatever particular channel our labours are directed. We have it on record that Newton, after the noblest effort of human reason that philosophy has perpetuated, conceived the idea that the laws governing the structure and functions of living organisms might be discovered by the comparison of their similar organs and functions, as were those of the inorganic world by the study of the uniformity of its phenomena. (" Idemque dici possit de uniformitate ilia quae est in corporibus animalium.") Until, however, the principles of philosophical induction are thoroughly understood, the peculiar combi326 Wuf.well's History of the Inductive Sciences. [April, nations in which vital phenomena present themselves to our notice, their apparent dissimilarity from the changes which we witness in the world around, and their obvious adaptation to particular ends, might lead us astray into the labyrinth of unprofitable speculation with regard to the presiding agencies by which they are governed; and the slightest acquaintance with the history of physiology will convince us that this has been the case up to a very recent period, and that in fact the legitimate objects of investigation and the true