Or take hydatid disease, which occurs in all parts of the world, and in some countries (Australia, Iceland) is terribly common. The nature of this disease--that it is an animal parasite transmissible between men and dogs--was proved by feeding-experiments on animals. In Iceland, where men and dogs live crowded together in huts, there is an appalling number of deaths from hydatid disease; Leuckart, in 1863, of it:-- "At present, almost the sixth part of all the inhabitants annually dying in Iceland fall victims to the echinococcus epidemic." Before Küchenmeister's experiments in 1852, there was no general knowledge of the exact pathology of entozoic disease. The advance was not made by the experimental method alone; other things helped: but among them was neither clinical experience, nor what Sir Charles Bell called "the observation of the just facts of anatomy and of natural motions." * * * * * Beside the entozoa, there are also vegetable parasites. Of these, the most important is the _streptothrix actinomyces_, the cause of actinomycosis in man and cattle. Israel, in 1877, gave the first accurate account of it in man; and Böllinger, the same year, studied it in cattle. Ponfick, in 1882, recognised the identity of the disease in man and animals. In 1885, Israel published the collected records of 37 cases in man, tabulated according to the site of the primary infection. Boström, about this time, made cultures of the fungus: but all the earlier attempts at inoculation failed; and it was not till 1891 that Wolff and Israel published their successful inoculations, and thus completed the evidence that actinomycosis is a parasitic infection, a growth of vegetable threads and spores, transmissible between men and animals, and able to keep its vitality outside its host; so that men who are employed with cattle, or have the habit of chewing straws or ears of corn, incur some slight risk of infection. Before 1877, the disease was hardly suspected in man, and was not understood in cattle. XII MYXOEDEMA On 4th October 1873, Sir William Gull read a short paper before the Clinical Society of London, "On a Cretinoid State supervening in Adult Life in Women." This famous first account of myxoedema was based on five cases: it is less than five pages long, it does not suggest a name for the disease, and it says nothing about the thyroid gland. Four years later (23rd October 1877), Dr. Ord read a paper before the Medico-Chirurgical Society of London, "On Myxoedema; a term proposed to be applied to an essential condition in the 'Cretinoid' Affection occasionally observed in Middle-aged Women." His work had begun so far back as 1861; and in this 1877 paper he gave not only clinical observations, but also pathological and chemical facts; and he noted, as one among many changes, wasting of the thyroid gland. He also pointed out the close resemblance between cases of myxoedema and cases of sporadic cretinism.