December 22, 192 1] 



NATURE 



537 



be forgotten that one of the functions of the Asso- 

 ciation is to inspire belief and confidence in science 

 as the chief formative factor of modern life, and 

 not only to display discoveries or enable specialists 

 to discuss technical advances in segregated sec- 

 tions. Though members of the Association may 

 be able to live on scientific bread alone, most of 

 the community in any place of meeting need some- 

 thing more spiritual to awaken in them the 

 admiration and belief which beget confidence and 

 hope. They ask for a trumpet-call which will 

 unite the forces of natural and social science, and 

 are unmoved by the parade of trophies of scien- 

 tific conquests displayed to them. It was the 

 primary purpose of Canon W. V. Harcourt, the 

 chief founder of this Association and its general 

 secretary from 183 1 to 1837, to sound this note 

 for " the stimulation of interest in science at the 

 various places of meeting, and through it the 



provision of funds for carrying on research," and 

 not for "the discussion of scientific subjects in 

 the sections." In the course of time these sec- 

 tional discussions have taken a prominent place 

 in the Association's programme, and rightly so, 

 for they have promoted the advancement of 

 science in many directions ; but, while we recog- 

 nise their value to scientific workers, we plead 

 for something more for the great mass of people 

 outside the section-rooms, for a statement of ideals 

 and of service, of the strength of knowledge and 

 of responsibility for its use. These are the sub- 

 jects which wiU quicken the pulse of the com- 

 munity and convert those who hate and fear 

 science and associate it solely with debasing 

 aspects of modem civilisation into fervent disciples 

 of a new social faith up>on which a lever made in 

 the workshops of natural knowledge may be 

 placed to move the world. 



Integration in the Living Organism. 

 By Prof. W. M. Bayliss, F.R.S. 



HTHE name "organism," given to the individual 

 * units of living matter as they are met with 

 in Nature, implies that these act as unified and 

 co-ordinated entities. At the same time, it must 

 be remembered that an organism considered apart 

 from its environment is merely a theoretical ab- 

 straction ; but, apart from the way in which they 

 react to external influences, there must be means 

 by which the activity of any one part is adjusted 

 to the needs of the whole, and the investigation 

 of these various means may be said to form a 

 large part of modern physiology. In a general 

 sense, it may be looked upon as distinctive of the 

 more recent outlook, for most of us are not con- 

 tent with ascribing the mutual co-ordination of 

 function to a presiding directive agency, be it 

 called "entelechy," "elan vital," or other mys- 

 terious influence. We want to know more of the 

 actual chemical and physical methods at work in 

 the process, and we believe that it is possible to 

 find out a great deal more about them than we 

 know as yet. The change in the point of view 

 of the physiologist may be realised better if we 

 pall to mind that it is no longer thought scientific 

 to devote attention to the "functions of the liver," 

 for example, but to those processes, such as de- 

 amination and regulation of carbohydrate supply, 

 in which this organ plays a part in combination 

 with various other tissues of the organism. We 

 ask : What part does the liver play in the cor- 

 related series of changes associated with the using 

 up of the materials of the food for the supply of 

 energy to, and for the growth of the cells of, the 

 organism as a whole? 



Broadly speaking, there are two great 

 " systems " — to use a term which is rather anti- 

 quated in this sense — that serve as the means of 

 communication between different parts of the 

 higher animals — the nervous system and the 



NO. 2721, VOL. 108] 



vascular system. There are corresponding means 

 of communicating by messages or by actual trans- 

 port of materials in the higher plants. As a first 

 approximation, we may call the former physical 

 and the latter chemical. These correspond to the 

 "nervous" and "humoral " factors of the French 

 physiologists. The central nervous system, in 

 addition to its obvious function of receiving im- 

 pressions from the outer world and reacting upon 

 it by reflexes to muscles, obtains messages from 

 the various parts of the organism itself by means 

 of appropriate receptors therein. Thus "effec- 

 tors " — muscles, glands, etc. — are modified in 

 their activity, and the special requirements of 

 active organs are met. For example, an active 

 secreting gland receives an increased supply of 

 blood, containing sugar and oxygen, by dilatation 

 of the blood vessels to it. By the blood, or similar 

 circulating liquid, a chemical substance made in 

 one place is carried over the whole of the 

 organism, and in special places adjusted to be 

 sensitive to it brings about appropriate reactions, 

 which may affect a large number of other organs. 

 Thus the carbon dioxide produced in active 

 muscles reaches the respiratory nervous centre, 

 exciting this to increase the ventilation of the 

 lungs and supply more oxygen to the muscles by 

 means of the blood. 



The comparison of the nervous system to the 

 telegraphic circuits of a city has often been made, 

 and is probably more to the point than is some- 

 times thought, since there are many reasons for 

 supposing that the passage of impulses along 

 nerves is essentially of an electrical nature. The 

 vascular system may similarly be compared to 

 mechanical transport, by which coal, for instance, 

 is conveyed in carts. In this latter case, material 

 substances are sent from place to place. Perhaps 

 a closer analogy to the blood vessels with their 



