Though Dr. Jenner could not tell us what Cowpox was, he soon came forward to inform us that it was of two sorts--the one genuine and harmless, the other spurious and hurtful. _Spurious_ Cowpox is a term I do not admit of. I know of no such thing as _spurious_ Smallpox, _spurious_ Measles, _spurious_ Lues Venerea, _spurious_ Scrofula. Birch’s objection to spurious cowpox was forcible, but what in the innocence of his heart he took for a blunder was proved out of Jenner’s own mouth to be a deliberate dodge in 1807. Pressed by the Committee of the College of Physicians to explain what he meant by Spurious Cowpox, he had to own that he knew nothing of such a malady, and that he had only meant to describe irregular effects of cowpox on the arms of the vaccinated! In other words, when vaccination turned out badly, he had found it convenient to ascribe the disaster to spurious vaccine! The policy revealed in this shameless avowal was cynically justified by Dr. Maunsell, who, in a well known volume, wrote-- The term _imperfect_ or _Spurious_ Vaccination is frequently to be met with in books, and has been the cause of no small degree of confusion in practice, although, at the same time, _it has frequently afforded the practitioner an excellent asylum against the storms now and then arising out of failures in the protective power of the vaccine disease_.[161] From out the muddle as to the origin of cowpox and its genuine and spurious varieties, Birch demanded, What had Jenner discovered? It is not that cowpox prevents smallpox; for that has been asserted by dairy-folk for generations, and has been disregarded by physicians because proved to be untrue. What then is it? Let him define his discovery that we may know how to respect it. Let him explain why it is forbidden to inoculate direct from the cow. Is genuine cowpox invisible and to be taken on trust? Or is the disease so virulent on its first communication that it has to be meliorated in the body of some victim ere it is fit for public use? Birch asked these questions as we continue to ask What is cowpox? Is it a disease of the cow? Or is it communicated to the cow by man or by horse? However definite the answers, the contradictions are equally definite, and the authorities equally trustworthy. Practical men answered for Jenner, as they presume to answer at this day, “Whatever may be the origin of cowpox, we know that vaccination is harmless, and that it prevents smallpox; and more we neither demand nor care to inquire.” The credulity and conceit of such practical men is that stupidity against which, says Goethe, even the gods are powerless. It was practical men who “on the mere show of reason” accepted vaccination before it could be tested, and on most superficial evidence, said Birch--