The relations of the circulation : address in medicine delivered at the Eightieth Annual Meeting of the British Medical Association / by G. A. Gibson.

Date:
1912
Catalogue details

Licence: In copyright

Credit: The relations of the circulation : address in medicine delivered at the Eightieth Annual Meeting of the British Medical Association / by G. A. Gibson. Source: Wellcome Collection.

Provider: This material has been provided by the Royal College of Physicians of Edinburgh. The original may be consulted at the Royal College of Physicians of Edinburgh.

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    of the actions and reactions continually in operation, and the character of the stimuli and responses likewise constantly at work. The circulation in all the higher animals may be regarded as based upon, or concerned with, four primary groups of principles. It is based upon mechanical arrange- ments which form the foundation for all its operations. It requires chemical changes, by which it is maintained, and for which it provides possibilities, by transference of matter. It is modified by glandular secretions, which profoundly alter its mechanism and chemical processes. It is affected by nervous agencies which deeply influence the performance of its functions. When we gaze upon the long line of being through which the mammal has been evolved we can discern certain different stages of development, physiological no less than morphological. Amongst the simple organisms belonging to the protozoa, physical and chemical agencies alone are required—simple structure and function are alone brought into play ; amongst the complex beings con- stituting the metazoa, glandular and nervous influences make their appearance with ever-increasing complexity— as we arise in the scale of life elaborate structure and function are necessary. To which part of the masque of life shall we wend our way in search of observations with which to illustrate the subject? Whithersoever we turn our eyes we can see but a small part of the drama at once- We do not yet stand “upon a Peak in Darien.” We can find examples of our meaning in the growth of youth and the decline of age, in conditions of health and states of illness. We shall have occasion, in looking into certain processes which are to occupy our attention, to trace out the development of nervous and glandular agencies in their evolution as well as involution; and it will be necessary for us also to glance briefly in passing at some particular diseases which will be helpful in lighting the path of inquiry. Many stages of being in the evolution of the mammal are analogous to phases of life in the development of its individual representatives. The analogies involve struc- ture as well as function. In the newly born there is not merely disproportion in the size of different parts and organs as compared with the adult, but there is also difference as regards function. It would serve no useful purpose on this occasion to dwell particularly on the infantile divergences from the normal of adult life as regards size and weight; but it is of importance to linger over certain deviations in function. The heart of the baby, in relation to the weight of its body, is considerably larger—expressed in percentages of total weight it is almost 0.9, as compared with a little over 0.5 in the adult —almost double; even more striking is the fact that the frequency of the heart beat is much greater, being from 130 to 140 per minute—roughly speaking, double that of the adult; the whole circuit of the blood is therefore traversed in a much shorter time—rather more than one-