TRANSACTIONS OF THE SECTIONS. 99 



was satisfied that the use of the Liver was to be the seat of prophetic agency for the 

 soul. Yet are we sure that, notwithstanding the researches of Bernard, Paw, 

 and others, we know even at this moment all the functions and uses of that organ F 

 How long since is it that taurine was found to contain 25 per cent, of sulphur, and 

 was not, as had been supposed, devoid of that substance r How complicated are 

 the chemical questions of the hepatic functions, when viewed as a whole through- 

 out the animal series, may be seen by a glance at fit. Milne-Echvards's summary of 

 these questions in his elaborate work now in course of publication. 



The utmost toleration is required in dealing with the prejudices which we are 

 considering: among other reasons, because truly there may be scientific prejudices 

 as well as popular prejudices. A scientific man maj- become impatient of every 

 opinion which rests only on probability ; whereas some of the important issues of 

 human affairs are not susceptible of absolute proof. A physician or a lawyer, or 

 a moralist, who always refused to act on the greater probability would be a sorry 

 adviser to his client. But the work of the chemist or the physiologist woidd be 

 at once set aside if probability and not ascertained fact entered into his formula. 



Different subject matters are taught or studied with different degrees of cer- 

 tainty, or by different methods ; the methods and degrees of certainty must be 

 known and acknowledged. There can be no just ground of objection to conclusions 

 based on hypothesis so long as the promoters are ready to accept, on proper and 

 reasonable evidence, new elements of calculation. 



I spoke also of the Passive prejudices of mankind in respect of Biology. A 

 curious chapter might be written on the slowness with which physiological 

 principles have been generally received (I cannot say they are even now accepted 

 by us) as the basis on which to secure public and private health. England is but 

 even now awakening to these questions. The Registrar-General, the Army and 

 Navy Departments, the Health Department of the Privy Council, the various 

 Drainage Commissioners and Committees, and many other bodies are all engaged 

 in collecting, disseminating, and in using physiological knowledge under various 

 aspects. It must be admitted that evidence as to what is and what is not favour- 

 able to the correct performance of the functions in men and other animals is 

 even now often conflicting. It was said just now that the pure Physiologist is 

 too apt to disregard the processes " prcepnrantes ad mortem ;" so also he is too 

 apt to look on Health Questions as problems of Practice or Art, and not of 

 Science. Yet the highest scientific qualities are requisite for determining with 

 precision any problems affecting, for instance, Nutrition, and the consequent Capa- 

 city for labour of a population, viewed as a whole or as individuals : witness the 

 investigations of your last year's President (now, happily, employed by the Govern- 

 ment), and many of the important papers in Mr. Simon's valuable yearly Keports, 

 and such memoirs as that of Professor Haughtou of Dublin on Work. In such 

 cases, I will not say Theory, but knowledge precedes, and regulates, and compels 

 practice. 



Similar considerations apply to the relation of Physiology to Practical Medicine. 

 This art or science is undergoing revision under the influence of Physiology, a re- 

 vision somewhat indeed retarded by popular prejudice, but certain. 



In looking back on the history of medicine we are at a loss to say which is the 

 more curious, the sagacity of the older physicians and surgeons, considering the 

 scantiness of their physiological knowledge, or their folly, considering the extent 

 of it. The explanation lies in the intermixture of empirical (that is, of accepted, 

 traditional, unquestioned) belief with really ascertained fact ; and we are not 

 now-a-davs without danger of undervaluing the eminent artistic power and great 

 practical shrewdness of former physicians, in the presence of our more precise, but 

 sometimes also less practically valuable scientific knowledge. Dr. Stokes, the 

 eminent Dublin Professor, has lately spoken on this topic in a timely and earnest 

 way. 



The business of Physiology and of an Association like this, as I j list now said, is 

 therefore not only to add new knowledge, but to destroy incorrect or imperfectly cor- 

 rect statement and belief. The incorporation of advancing Physiology with Medicine 

 every year adds certainty to the latter, while it furnishes data as weil as tests to the 

 former. Experiment properly applied in Medicine under trained physicists and 



7* 



