with vigour for the rest of the century. We need only mention the Englishmen-Cowper, Glisson, Havers, Highmore, Lower, Willis, and Wharton; the Danes-Steno, Bartholinus, and Worm; the Germans-Kerkring, Meibom, Schneider, and Wirsung; the French-Vieussens and Duverney; the Swiss-Peyer and Brunner; the DutchDe Graaf and Nuck; all contemporary physicians whose names are immortalised in various parts of the human body. The work of some of them will be referred to hereafter, but we must conclude for the present by noticing two discoveries, the great importance of which was long overlooked.

Dr. Richard Lower had proved, by experiments on animals, that the change from venous to arterial blood takes place only in the lungs, and only in the presence of atmospheric air; as, indeed, Servetus had asserted a century earlier. But his friend John Mayow (1645-79), one of the greatest physiologists of the seventeenth century, carried the investigation a step farther, and showed that the agent of this change is a particular constituent of the air, which also supports combustion and is contained in nitre, and which he therefore called "nitro-aerial spirit". In short, he had discovered oxygen, though it had to be rediscovered a century later.

In September, 1683, Antony van Leeuwenhoek wrote from Delft to the secretary of the Royal Society announcing his discovery in the white matter between his teeth of microscopic animals, "moving in the most delightful manner”; and he added a sketch in which we may clearly recognise the four chief forms of microbe, the longer and shorter rods of bacilli and bacteria, the minute spheres of the micrococci, and the corkscrew-like spirillum. He expresses his wonder that, in spite of his care in cleaning his teeth, his mouth should contain more "animals" than there are human beings in the united Netherlands, and says he had tried in vain to get rid of them by washing his teeth with vinegar. Sometime afterwards he began to take hot coffee, and the microbes disappeared, but they soon returned, in spite of

continued coffee drinking. Leeuwenhoek says he hopes the fellows of the Royal Society will be interested by this novelty, but he certainly had no idea that the discovery was destined one day to exert a greater influence both on medicine and surgery than even that of the circulation.

NOTES.

Van Helmont's dream is from his Tumulus Pestis.

Harvey's Exercitatio Anatomica has frequently been republished since 1628, and is translated into most civilised languages. Perhaps the best English version is that by Willis, Sydenham Society, 1847; see also the biography by the same writer, London, 1878.

Works on the circulation of the blood are innumerable; among the most important are Hecker, Die Lehre vom Kreislauf vor Harvey, Berlin, 1811; Flourens, Histoire de la Découverte de la Circulation du Sang, Paris, 1844; the above mentioned works of Dr. Willis; three papers in the Lancet, 1876-77, by S. Gamgee; Kirchner, Die Entdeckung des Blutkreislauf, Berlin, 1878. The boldest attempt to deprive Harvey of the honour of the discovery was that made by Ceradini (La Scoperta della Circulazione del Sangue, Milan, 1871) on behalf of Cesalpino. It is fully refuted in the later treatises noticed above, especially that by Kirchner.

Malpighi describes his experiments in his letters to Borelli, De Pulmonibus, Bologna, 1661. Aselli, De Lactibus seu Lacteis Venis, etc., Milan, 1627.

There was a long controversy between Rudbeck and Bartholinus about the lymphatics. The truth seems to be Rudbeck first discovered them, while Bartholinus first published an account of them. An English physician, Joyliffe, observed them about the same time but published nothing on the subject. Aselli had already (in 1627) described and figured the lymphatics of the liver, though he unfortunately mistook them for the endings of the lacteals.

A biography of Mayow is given by Sir B. Richardson in his Asclepiad, 1887, see also Gamgee's Physiological Chemistry, vol. i. Leeuwenhoek, Arcana Naturæ, Delft, 1697.

LII. VAN HELMONT.

JOHN BAPTIST VAN HELMONT (1577-1644) is almost as striking a figure in medical history as Paracelsus, whom he re

sembles in many respects, though he surpassed him both in genius and learning. His character is so closely connected with his doctrines, that it will be necessary to give a few biographical details. The youngest son of a noble Flemish family, Van Helmont lost his father in childhood, and received a pious and strictly Catholic education from his mother. He then went through the university course at Louvain, but refused the degree of M.A., declaring that so far from being "Master" of the seven liberal "Arts," he was not even a disciple in one, and that his knowledge, like Adam's, had served only to show his nakedness. After dabbling in magic, he betook himself to the study of ethics, as the only worthy form of knowledge, and read especially the works of Seneca, Epictetus, Thomas à Kempis, and John Tauler, a mixture of Stoic philosophy and Christian mysticism which did not fail to produce a moral nightmare. He dreamt he saw himself like a huge empty bladder reaching from earth to heaven, but above him, instead of heaven, was a coffin, and below him the blackness of the abyss. So he saw that Stoicism is but a form of pride, and man, without the inspiration of God, a thing of nought and a vain shadow. A rich living was offered him if he took orders, but he was frightened by the saying of St. Bernard, that he would live from the sins of the people. Then he thought of law, but soon found that its ordinances were often far removed from truth and justice, and how should he guide and restrain others who found it hard enough to govern and direct himself? So he turned to Dioscorides and Matthioli to study the goodness of God in the virtues of herbs, and this led him to medicine. Here, he thought, was a science in which a student bent upon relieving the miseries of his fellows could not fail to receive Divine assistance, and the great teachers of which must be men inspired of God, even as were Bezaleel and Aholiab, the builders of the Tabernacle. He carefully studied all the approved medical authors, taking notes of everything that seemed valuable; then he read the notes. and was overwhelmed with disappointment and despair.

"I said in my heart: 'O merciful God, how long wilt Thou be angry with man, that Thou hast not revealed one truth to Thy students in healing? Is this Moloch sacrifice pleasing to Thee, and wilt Thou that the lives of the poor, of widows, and of children, be continually offered up to Thee in miserable torments of incurable diseases or through the carelessness and ignorance of physicians?' Then I fell on my face and cried: Lord have mercy! pardon, pardon me, O Lord, if love of my neighbour has led me beyond bound, for Thou art the root of all goodness, Thou knowest my sighing, and that I confess I am empty, ignorant, poor, and naked, and have nothing, am nothing, and can do nothing'. But he was encouraged by a dream to persevere in his work, and having taken the degree of M.D. at Louvain, set himself no less a task than "to overthrow the entire philosophy of the ancients and establish a new science of Nature." The existing medicine, he says, is based on that of the pagan Greeks, and considers only the outside of things, but Christian science like Christian morality must begin from within.

To Van Helmont all nature is alive; there is no such thing as dead matter, but in animals this material life, as we may term it, assumes an almost personal form, which he calls "Archeus," a word already used, though more vaguely, by Paracelsus and Basil Valentine. Every bodily structure has its local "Archeus insitus," and the whole organism is governed and directed by an "Archeus influus" who builds up the body and supports its activity, working always according to a fixed plan, or "seminal idea" impressed by the Creator. This Archeus resides in the stomach, and is closely connected with the sensitive and rational soul, the two together forming a sort of husk or shell for the higher intuitive or intellectual spirit. For Van Helmont distinguishes between intellect and reason, and declares that the latter is an inferior quality, acquired by, and necessary to, man since the Fall, but leading nearly as often to error as to truth. The heathen Aristotle in his blindness bowed down to reason, and set it up as an idol in the form of Logic, a vain science,

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which deals only with externals and definitions. One definition, indeed, is important in medicine-that of disease, for it is not a mere matter of words, but affects the lives of men; and here the pagans and their Christian disciples have gone hopelessly astray in spite of their logic. For they call disease Ia lesion of structure or functions," and declare that its cause is a change in the fluids or humours, the disease itself being in the solids, while the spirit or "pneuma" directs the symptoms. The reverse is the truth, for disease affects the life, and must, therefore, have its seat in the life, or Archeus, through whose action it produces changes in the solids and fluids. How can an organic lesion be a disease, for it persists in dead bodies, and the dead can have no disease? "Whatever produces healthy actions in the sound, the same causes vitiated actions in diseases." (Quidquid in sanis edit actiones sanas, idipsum in morbis edit actiones vitiatas.) Disease is a morbid idea conceived by the Archeus, either through his own infirmity, or from the action of some harmful agent, which causes him to deviate from his normal course and act in another way, but always after some fixed and specific plan. There are thus two great divisions—(1) innate diseases, under which head he classes inherited and latent affections, such as epilepsy, and (2) those due to external agencies, among which the results of witchcraft, injecta a sagis, play a large part.

He applies these doctrines to special instances with much ingenuity. Fevers, say the Galenists, are either simple, and due to præternatural heat originating in the heart, or putrid, caused by a corruption of the humours, especially the blood; and they treat them by bleeding, purgation, and cooling medicines. This, according to Helmont, is false, for heat is merely a symptom, and the blood never putrefies during life. Fever is the effort of the chief Archeus to get rid of some irritant, just as local inflammation is the reaction of the local Archeus to some injury. The heat is caused by the anger of the Archeus, who tries to shake off his enemy by calling up cold and hot fits, a blas frigoris and blas caloris and