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from the air it is as if heat were rather enkindled within the foetus, than repressed by the influence of the air. This much, by the way, on the subject of Respiration; hereafter perhaps, I may treat it at greater length." That Harvey should have suspected the truth, to be revealed long afterwards, that heat was enkindled by respiration, is a most remarkable proof of his genius. For Chemistry may be said not to have been born till after the words just quoted were written. Harvey published his work on Generation in the year 1651, and at that time Robert Boyle was twenty-five years of age. Boyle has been called the Father of Modern Chemistry, and we are now are now on the threshold of the chemical era of medicine.

1 Harvey's Works, p. 530.

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DES CARTES.-SYLVIUS DE LA BOE.-ROBERT BOYLE. Des Cartes' birth-His exile in Holland-His death in Sweden-His Physical Philosophy-His Vortices-Futility of his Physical Speculations-Sylvius de la Boe-Guy Patin-Use and Abuse of Antimony-Dialogue on Blood-letting between Willis and Van Helmont-Sylvius' Theory of Digestion-Guy Patin's Definition of Cardinal Mazarin-Bonteke's Praise of Tobacco-Robert Boyle -His Studies-Inclination towards Medicine-Just Estimate of ChemistryObjections to Compound Prescriptions-Expectation from Specifics-Objections to Specifics answered.-The Dose of a Specific.-Boyle the Expounder of the Baconian System of Medicine.

DES CARTES was born in 1596, Sylvius in 1614, twelve years before Bacon's death; and Boyle in 1627, the year Bacon died. René Des Cartes, or Latinised, Renatus Cartesius,

was a gentleman of Brittany, a military man, possessing, in the highest degree," says his distinguished countryman, "our defects and our qualities; clear, firm, resolute, somewhat rash; thinking in his closet with the same intrepidity with which he fought under the walls of Prague." He

1 C. Van Dalen, junior, del. et sculpt.


2 Victor Cousin's History of Modern Philosophy.

passed the greater part of his life a voluntary exile in Holland, where he conceived he might enjoy greater liberty than he could in France. He died in Sweden, whither he had gone at the invitation of Queen Christina; and he is said to have been sacrificed to the rigour of the Swedish climate, as administered by his eccentric hostess, who insisted upon studying with him at five o'clock in the morning. "To Des Cartes," says Playfair, "belongs the honour of being the first who ventured on the solution of the most arduous problem which the material world offers to the consideration of philosophy. For this solution, he sought no other data than matter and motion, and with them alone proposed to explain the structure and constitution of the universe. The matter which he required, too, was of the simplest kind, possessing no properties but extension, impenetrability, and inertia. It was matter in the abstract, without any of its peculiar or distinguishing characters. To explain these characters was, indeed, a part of the task which he proposed to himself; and thus, by the simplicity of his assumptions, he added infinitely to the difficulty of the problem which he undertook to resolve." begins," says Whewell, "with his celebrated assertion, 'I think, therefore I am,' which appears to him a certain and immovable principle, by means of which he may proceed to something more. Accordingly, to this he soon adds the idea, and hence the certain existence of God and his perfections. He then asserts it to be also manifest, that a vacuum in any part of the universe is impossible; the whole must be filled with matter, and the matter must be divided into equal angular parts, this being the most simple, and therefore the most natural supposition.3 This matter being in motion the parts are necessarily ground into a spherical form, and the corners thus rubbed off (like filings or sawdust) form a

1 Biographical Dictionary.

Preliminary Dissertations to En

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currents, or vortices.

There is, besides, a third


second or more subtle matter.1 kind of matter, of parts more coarse and less fitted for motion. The first matter makes luminous bodies, as the fixed stars; the second is the transparent substance of the skies; the third, the material of opaque bodies, as the earth, planets, and comets. We may suppose, also, that the motions of these parts take the form of revolving circular By this means, the first matter will be collected to the centre of each vortex, while the second, or subtle matter, surrounds it, and by its centrifugal effort constitutes light. The planets are carried round the sun by the motion of the vortex,* each planet being at such a distance from the sun as to be in a part of the vortex suitable to its solidity and mobility. The motions are prevented being exactly circular by various causes; for instance, a vortex may be pressed into an oval shape by contiguous vortices. The Satellites are in like manner carried round their primary planets, by subordinate vortices; while the comets have sometimes the liberty of gliding out of one vortex into the one contiguous, and thus travelling in a sinuous course from system to system through the universe." 5 Although Des Cartes himself styled his famous theory of vortices " A Philosophical Romance," yet it exerted a powerful influence upon the course of speculation both in physiology and pathology. Des Cartes was one of the earliest and most zealous supporters of Harvey, and while he accepted and defended the explanation given by our patient countryman of the cause of the circulation of the blood, he added to it his own imaginative hypothesis as to the production of animal heat. This he conceived to be owing to a fermentation of the blood in the heart; he compares it to the chemical action of an acid upon a metal, and the cause

1 Principia, p. 59.

2 Ibid., p. 56.

3 Ibid., p. 61.

Ibid., c. 140, p. 114.

5 Whewell's History of the Physical Sciences.

6 Sir William Hamilton's Dissertations on Philosophy, p. 304.

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