Organism and Environment as Illustrated by the Physiology of Breathing

The distinctively biological conception which I have endeavoured to formulate more definitely in these lec- tures enables us to interpret what are ordinarily re- garded as biological phenomena. But the higher organisms, at any rate, are also centres of knowledge and volition. It is unmeaning to treat consciousness as a mere accompaniment of life, or to ignore the differences between blind organic activity, and rational behaviour. Conscious personality is far more than mere organism, and the conception of life is just as inadequate in connection with personality as the con- ceptions of matter and energy in connection with life.

It is not the time and place to recapitulate the rea- soning which leads to this conclusion ; but we may, per- haps, ask why, if the reasoning is correct, there is still a place for human physiology as distinguished from psychology. The practical reason is that although a man is a person and not a mere organism, we cannot trace personality throughout all, or nearly all, of what we observe in a man. To interpret the details as best we can, we have to fall back on the conception of life in the biological sense, just as in details of what we observe in connection with living organisms we have to fall back on ordinary physical and chemical inter- pretations. Though we know that these interpreta- tions on a lower plane of knowledge can only be pro- visional, yet we should be very helpless in practical life without them. Their practical value is unmis- takable, and we cannot dispense with them. On this view the conflicts between materialism and spiritual- ism, realism and idealism, science and philosophy, are only apparent.

In establishing the Silliman Lectures, the Founders, although they left complete freedom to lecturers to treat their subjects as they thought fit, expressed the wish that the courses should have reference to "the presence of God in the natural and moral world." It is with hesitation that I venture to refer to this wish : for I know that in some ways my own conclusions are probably different from those of many who have thought very deeply on this subject.

In the preceding lectures I have endeavoured to describe the results of investigations on the physiology of breathing, and at the same time to show that these and other investigations lead to a biological concep- tion of life which cannot be reconciled with the mechanistic conceptions handed down to us from the latter half of the last century. I have also argued that in virtue of this biological conception we must claim for biology an independent position as a science deal- ing with the manifestations of an order immanent in the natural world. This order is of a far more inti- mate character than the order hitherto disclosed by study of what we at present call the inorganic world.

To some men it has seemed that the facts of organic life furnish evidence of the existence of an external creator. The writings of Paley, for example, have popularised this view. If, as Paley tacitly assumed, organisms were machines there would be some basis for this argument: for the formation of the body cannot be explained as a physical and chemical pro- cess. The hypothesis that the body is formed in each individual by an act of miraculous creation would at any rate serve to stop a gap in our knowledge, though a God who did nothing but create machines would be

a mere Juggernaut. We have seen, however, that organisms are not machines, and with the machine theory the argument, such as it was, for special crea- tion disappears. Biology leads us to the conception, not of an external Creator, but of an order immanent in the natural world. This order is, however, conceived as blind and unconscious, and cannot, so conceived, be identified with what we have learnt to understand as God. It is not from the data of biology, and still more clearly not from those of the physical sciences, that we derive our conception of God, but from the facts of knowing and consciously doing which we observe in ourselves and our fellow men as conscious person- alities. In knowledge the mind extends itself over our whole universe, so that what exists for us exists as known, however imperfectly, and as a sphere of our activities, however imperfect these activities may be. But we find that neither knowledge nor conscious activity in general is the mere knowledge or activity of individual men. Just as the behaviour of the cells in a compound organism is unintelligible if they are con- sidered one by one, apart from their relations to the whole organism, so the acquisition of knowledge and conscious activity in general, are unintelligible from the point of view of the individual man. We can endeavour to picture to ourselves a man who would be entirely self-centred — who would be a God to him- self ; but the attempt ends in failure. It is the percep- tion that in us as conscious personalities a Reality

manifests itself which entirely transcends our individ- ual personalities, that constitutes our knowledge of God. In the world of duty and knowledge, not in the natural world as such, we find the God whom our fathers have worshipped, and in whose strength they have been of good courage, and faced trouble, danger and death. God is near to us, and not far away. The facts of biology lead to the conclusion that the physical and chemical interpretation of the world is fundamentally imperfect, however useful it may be. The biological interpretation is itself similarly imper- fect in view of the facts relating to conscious person- ality. But when we regard the natural world, as it seems to me we ought and must, not as something com- pletely interpreted in the light of existing theory, but as an imperfect interpretation which is the expres- sion of countless centuries of human effort, the natural world becomes part of the world of duty and knowl- edge. Natural science and its applications are the rough-hewing in the spiritual world, and the funda- mental conceptions of each of the natural sciences are the tools, fashioned by human endeavour, with which this rough-hewing is done. Scientific results are in themselves only incomplete and abstract presentations of reality, just as the stones are not part of the build- ing till they are dressed and fitted into place. Other workers do their part in the building, but without the rough-hewing their efforts would be in vain. Biology, for instance, is absolutely dependent on the preliminary work of the physical sciences, just as other more con- crete sciences are dependent on biology. The claim

is often made, either explicitly or implicitly, and in our own times particularly on behalf of the mathema- tical and physical sciences, that scientific results repre- sent complete and "objective" reality. This claim can- not be justified. We learn to know God, not by any process of ab- stract reasoning or external revelation, but by practic- ally realising in our own everyday lives, and those of our fellow men, that we are not mere individuals but one with a higher Reality. In losing our individual lives we find our true life, and in no part of human activity is this losing of the individual self more clearly realised than in scientific work. When, but only when, we see that the natural world appears to us as it does through the devoted scientific work which has fashioned its present appearance, we have found God in the natural world. The life of such a man as Charles Darwin is in truth a standing proof of the existence of God.

I think the Founders of the Silliman Lectures must have felt this when they left complete liberty to each lecturer to treat his subject just as seemed best for his immediate purpose, and without reference to theology. Abruzzi, Duke of the, 58 Absorption curve of carbon dioxide, constancy of, 34 effect of dissociation of effect of rise in venous pressure on, 73 Acclimatisation, at high alti- tudes, 48, 56, 58, 59 at high altitudes, effect on haemoglobin percentage, at high altitudes, factors in,

formation in, 39 Acidosis, ammonia formation in, 39 effect on alveolar CO2, 27 Acids, effect on alveolar CO2, effect on breathing, 35 effect on dissociation of oxy-haemoglobin curve, effect on respiratory cen- tre, 36 Activity, "normal," 1 Adaptation, alteration of the normal in, 102 in memory, 97 in reproduction, 98 of epithelium to injury, 96 structural changes in, 94 to changes in environment, to disease, 95, 96 to injury, 95, 96, 97 to oxygen want, 94 to repeated bleeding, 95 to repeated blood transfu- sion, 95 Adrenal, glands in regulation of vaso-constriction, 75, Adrenalin, in regulation of

vaso-constriction, 75 Aerotonometer, 53 Aggregation of haemoglobin by inorganic salts, 31 Air, supply, to divers, 20 regulation of, 4 vitiated, 18 Albuminous substances in blood, as weak acids, 32 of oxyhaemoglobin, 31 Alps, 50 Altitudes, acclimatisation at, blood reaction at, 50, 51 circulation rate at, 57 dissociation of oxy-haemo- at, 56 effect on blood volume, 52 effect on breathing, 47, 48 effect of oxygen deficiency at, 47, 49 increase of red blood cor- puscles at, 51 oxygen consumption at, 57 oxygen pressure in blood

relation to barometric pres- sure, 14 Alveolar carbon dioxide pressure, and percentage, relation to barometric pressure, 14 relation to alveolar oxygen pressure, 49 Alveolar oxygen, constancy of, 10 high altitudes, 61 Alveoli, aqueous vapour in, CO2 percentage in, 8, 9, 13 Ammonia, formation in aci- dosis, 39 formation in intestines, 39 in regulation of blood al- kalinity, 38, 39 Anglo-American expedition, artificial respiration dur- ing, 25 chemical, 22 CO2 in alveoli and arterial

Artificial respiration, 25 during apnoea, 25 and Hering-Breuer inhibi- tion, 25 Balloon ascensions, acclima- tisation in, 59 effect of oxygen want in, Bleeding, eflFect on blood vol- ume and regeneration of red blood cells, 80, 81 eflFect of repeated, 81, 95 Blood, absorption curve of carbon dioxide in, Z2, ZZ^ arterial gas pressure of, 71, carbon dioxide in, 21, Z2 changes in lungs, ZZ colour of, 6, 7 dissociation curve as reac- tion index of, 31

sugar contents of, 76, 11 Blood, concentration after sweating, 79 venous gas pressure of, 71, Blood composition, and spe- cific "structure," 90, 91 subordinate centres regu- lating, 70 Blood alkalinity, 36, 38 alkalinity) Blood transfusion, effect on blood volume and red blood corpuscles, 80, 81 effect of repeated, 81, 95 Blood volume at high alti- tudes, 52 effect of bleeding on, 80 effect of transfusion, 80, Bohr, 30, 53, 63 Bone marrow, formation of red blood corpuscles in, Boothby, 71 Boycott, 50, 80, 95 Breathing, 3, 100, 101 after excessive ventilation,

of, 34 during exercise, 10 effect of acids on, 35 effect of alkalis on, 35 effect of alveolar CO2 on, on, 42, 43 effect of partial obstruc- tion on alveolar CO2, 13 essential factors in, 3 extent of voluntary con- trol, 11 frequency relation to alve- olar CO2, 12 in diabetes, 35 in regulation of alveolar Canaries, in detection of small percentages of car- bon monoxide, 46 Capillaries, activity of walls after bleeding and trans- fusion, 80 passive congestion in regu- lation of venous pres- sure, 74, 75* Carbon dioxide, 3, 4

violent exercise, 41 effect on divers, 19, 20 effects on circulation, 15 in arterial blood, 27, 32 in chemical combination in contents of blood, 72 "mass influence" of, 32 regulation of circulation rate by, 76 relation of barometric pressure to partial pres- sure of, 13 removal in a vacuum, 32 secretion by lungs, 67 Carbon dioxide in alveoli, and frequency of breath- ing, 12 at high altitudes, 47 essure to van are of, 13 moval in \ vac ecretion by hiar' rbon dioxidi and freqoer ing. 12 at high a}titiide&.'

Electric conductivity of se- rum after drinking dilute sodium chloride solution, after excessive water in- take, 78, 79 Electrolytic dissociation, 107 Embryo, development of, 110, Epithelial cells of lungs, gas- eous exchange by, 52, 53 function of, 61 secretion of oxygen by, 53, selective secretion, 62 Epithelium, adaptation to in- jury of, 96 Erythrocytes (see red blood aggregation of molecules by inorganic salts, 31 behaviour as a weak acid, monoxide with, 45 function of, 7 percentage, after excessive water drinking, 78 at high altitudes, 51, 52,

effect of increased oxy- gen pressure on, 52 Hasselbalch, 36, 49, 51 Heart, function of, 12 nerve supply, IZ regulation of circulation rate by, 12, IZ regulation of discharge, 74 sympathetic control, IZ vagus control, 12> Hemorrhage, effect of (see Hering-Breuer inhibition and alveolar COo, 25 and artificial respiration, 25 Himalayas, 58 Hook, 6 Immunity to micro-organ- isms, 95 to poisons, 95 Inspiration, cause of, 22 Intestines, formation of am- monia in, 39 passage of salts into, after excessive water drinking,

Kidneys, excretion of water, in regulation of blood re- action, 39, 40, 51 Kidney secretion, 64, 65 effects of drugs on, 65 effects of excessive water Lactic acid, formation during muscular exertion, 35, formation in oxygen defi- ciency, 35, 50 in urine after violent mus- cular exertion, 41 Liver, destruction of red blood cells by, 81 regulation of alkalinity of Living structures, character- istics of, 66 molecular activity in, 66, 67 Lung epithelium, gaseous ex- change by, 52, 53 function of, 61 oxygen secretion in rela- tion to CO2 pressure, 62,

"Materialism," 108 Matter, relationship of, 107 Mavrogorato, 23 Mayow, 3 Mechanism, 2, 99 and regulation of breath- ing, 16 Mechanistic theory of life, of regulation, 5 Medulla oblongata, 5, 21, 70 Memory, adaptation in, 97 Metabolism, effect on vaso- motor nerves, 70 in regulation of circula- tion, 75 nitrogen, 83, 84 of cell, 85 Muscular exertion, at high altitudes, 56 lactic acid formation dur- ing, 35, 41, 50 of blood alkalinity, 39 Normals of anatomy, 102 Nutrition, coordination in, 81

under compression in CO poisoning, 45 Oxygen consumption, and rate of circulation, 71, 16 symptoms of, 42, 43 Oxygen percentage, in alve- oli, regulation of, 10 in sea water, 62 Oxygen secretion, at high altitudes, 56, 57 relation to oxygen pressure in lungs, 63, 64 Oxy-haemoglobin, dissocia- tion of, 29 regulation of blood gases by, 72 Oxy-haemoglobin dissocia- tion curve, 29, 30 Partial pressure CO2, rela- tion to barometric pres- sure, 13 hlood alkalinity) Reaction of urine, 40 Reality, "objective," 118 Red blood corpuscles, 28

relation of dissociation curve to salts in, 31 Regnault, 108 of temperature, 80, 89 of temperature in dog, 13 of vaso-constriction by ad- renals, 75 of water contents of blood, Reproduction, 98, 114 Respiration (see breathing) Respiration, artificial, 25 artificial, and Hering- Breuer inhibition, 25 artificial, in apnoea, 25 effect of CO2 pressure on, Respiration rate, and alveo- lar CO2, 12 Respiratory center, 5, 17, 24, and hydrogen-ion concen- tration, 2,7, 89, 111, 112 as index of blood alkalin- ity, 38 blood constancy to, 38 delicacy of response, 14, 15 effect of acids on, 2i6 effect of alveolar CO2 on,

effect of drugs on, 86 effect of excessive ventila- tion, 47 effect of oxygen deficiency influence of pulmonary in- flation and deflation on, latency of response, 11 Salivary secretion, 68, 69 Salts, aggregation of haemo- globin by, 31 passage into intestines af- ter water drinking, 78, 79 Sampling, alveolar air, 8 Schafer, Sir Edward, 17 method applied during ap- noea, 25 Schmiedeberg, 38 Schneider, 55 Scott, 25 Sea water, CO2 pressure in, Suprarenal glands, and vaso- constriction, 75 in physiological regulation,

Sweating, effects on blood concentration, 79 effects on blood constitu- ents, 79 effects on urine secretion, Swim bladder of fishes, ef- fects of drugs on oxygen secretion of, 63 function of, 62, 6'i oxygen secretion in, 64 structure, 63 Sympathetic nerves, to heart, Urea excretion, 83 in starvation, 83 Urine, "buffer substances" in lactic acid in, 41 nitrogen of, as index of blood alkalinity, 39 reaction of, 40 secretion, effect of sweat- ing on, 79 sodium chloride of, after large intake of water, 78

Vagus apnoea, 22 Vagus nerves, effect of cut- ting on breathing, 21, 25, influence on breathing, 21, Vaso-constriction, chemical, nervous, 70 regulation by adrenal glands, 75 regulation of circulation rate by, 72 Vaso-motor center, 70 control of local blood sup- ply by subordinate, 70 Vaso-motor nerves, 70 Veins, regulation of venous pressure by contraction of peripheral, 74 Venous constriction, in rela- tion to COo contents of blood, 74, 75 Venous gas pressure, 71, 72

regulation of, 72 Venous pressure, effect on accelerator nerve, IZ, 74 in regulation of output of blood, 74, 75 regulation by passive con- gestion of capillaries, 75 regulation by peripheral constriction of peripheral veins, 74 Ventilation in mines, 19 Vicarious function, 97 "Vital force," 110 "Vital mechanisms," 11 "Vital principle," 2, 4, 82, Voluntary control of respira- tion, 11 Von Baer, 3 Von Bezold, IZ