Filterable Virus Diseases in Man

Laenniec had written his great work on Auscultation: a work the result of his own elaborate researches, and is the basis of our knowledge of disease of the lungs and heart in the living; even supplying the nomenclature for the pheniomena observed which is current to this day. As has been said of him: "He unlocked the secrets of the heart and lungs, and by his great researches made a thorough investigation of their physiology and pathology. Before his day the various sounds characteristic of valvular lesions of the heart were not known, and the diagnosis of these conditions was made on the postmortem table. " My reason for intro(ducing Laennlec in this paper is that while apparently he discovered the stethoscope by a fortunate circumstance, yet in reality he did so in consequence of his opportune ap,plication of a physical truth, and that both before his discovery and after it he was a most diligenit seeker after and recorder of facts; indeed, had it not been for this, it is quite possible he might have overlooked the importance of his discovery, epoch-making as it was. In conclusion, let me quote the wise words of Sir James Paget: "Darwin had the rare power of taking the common things that other men waste, and out of them making the grandest material of scientific work; so that it is in vain to say in any branch of practice, 'I have no opportunity for scientific inquiry, I cannot investigate this, I can contribute nothing to that which I see the scientific members of my profession are doing.' " It requires merely the opportunity of practice in the country, and the mind and resolution of Darwin, to bring great pathological conclusions out of the most ordinary facts of daily life in general practice. "The commonplace is of all knowledge that which we can least afford to despise or disregard."