Cardan begins with a definition of Subtilty. "By subtilty I mean a certain faculty of the mind by which certain phenomena, discernible by the senses and comprehensible by the intellect, may be understood, albeit with difficulty." Subtilty, as he understood it, possesses a threefold character: substance, accident, and manifestation. With regard to the senses he admits but four to the first rank: touch, sight, smell, and hearing; the claims of taste, he affirms, are open to contention. He then passes on to discuss the properties of matter: fire, moisture, cold, dryness, and vacuum. The last-named furnishes him with a text for a discourse on a wonderful lamp which he invented by thinking out the principle of the vacuum. This digression on the very threshold of the work is a sample of what the reader may expect to encounter all through the twenty-one books of the De Subtilitate and the seventeen of the De Varietate. Regardless of the claims of continuity, he jumps from principle to practice without the slightest warning. Intermingled with dissertations on abstract causes and the hidden forces of Nature are to be found descriptions of taps and pumps and syphons, and of the water-screw of Archimedes, the re-invention of which caused poor Galeazzo Rosso, Fazio's blacksmith friend, to go mad for joy. There are diagrams of furnaces, of machinery for raising sunken ships, and of the common steelyard. Cardan finds no problem of the universe too recondite to essay, and in like manner he sets down information as to the most trivial details of every-day economy: how to kill mice, why dogs bay the moon, how to make vinegar, why a donkey is stupid, why flint and steel produce fire, how to make the hands white, how to tell good mushrooms from bad, and how to mark household linen. He treats of the elements, Earth, Air, and Water, excluding Fire, because it produces nothing material; of the heavens and light: metals, stones, plants, and animals. Marvellous stories abound, and the most whimsical theories are advanced to account for the working of Nature. He tells how he once saw a man from Porto Maurizio, pallid, with little hair on his face, and fat in person, who had in his breasts milk enough to suckle a child. He was a soldier, and this strange property caused him no slight inconvenience. Sages, he affirms, on account of their studious lives, are little prone to sexual passion. With them the vital power is carried from the heart to a region remote from the genitals, i.e. to the brain, and for this reason such men as a rule beget children weak and unlike themselves. Diet has a valid effect on character, as the Germans, who subsist chiefly on the milk of wild cows, are fierce and bold and brutal. Again, the Corsicans, who eat young dogs, wild as well as domestic, are notably fierce, cruel, treacherous, fearless, nimble, and strong, following thus the nature of dogs. He argues at length to show that man is neither an animal nor a plant, but something between the two. A man is no more an animal than an animal is a plant. The animal has the anima sensitiva which the plant lacks, and man transcends the animal through the gift of the anima intellectiva, which, as Aristotle testifies, differs from the sensitiva. Some maintain that man and the animals must be alike in nature and spirit, because it is possible for man to catch certain diseases from animals. But animals take certain properties from plants, and no one thinks of calling an animal a plant. Man's nature is threefold: the Divine, which neither deceives nor is deceived; the Human, which deceives, but is not deceived; the Brutish, which does not deceive, but is deceived. Dissertations on the various sciences, the senses, the soul and intellect, things marvellous, demons and angels, occupy the rest of the chapters of the De Subtilitate.
At the end of the last book of De Varietate, Cardan gives a table showing the books of the two works arranged in parallel columns so as to exhibit the relation they bear to each other. A comparison of the treatment accorded to any particular branch of Natural Philosophy in the De Subtilitate with that given in the De Varietate, will show that in the last-named work Cardan used his most discursive and anecdotic method. Mechanics are chiefly dealt with in the De Subtilitate, and all through this treatise he set himself to observe in a certain degree the laws of proportion, and kept more or less to the point with which he was dealing, a system of treatment which left him with a vast heap of materials on his hands, even after he had built up the heavy tome of the De Subtilitate. Perhaps when he began his work upon the fresh volume he found this ingens acervus too intractable and heterogeneous to be susceptible of symmetrical arrangement, and was forced to let it remain in confusion. Few men would sit down with a light heart to frame a well-ordered treatise out of the débris of a heap of note-books, and it would be unjust to censure Cardan's literary performance because he failed in this task. Probably no other man living in his day would have achieved a better result. It is certain that he expended a vast amount of labour in attempting to reduce his collected mass of facts even to the imperfect form it wears in the De Varietate Rerum.[120]
Considering that this book covers to a great extent the same ground as its predecessor, Cardan must be credited with considerable ingenuity of treatment in presenting his supplementary work without an undue amount of repetition. In the De Varietate he always contrives to bring forward some fresh fact or fancy to illustrate whatever section of the universe he may have under treatment, even though this section may have been already dealt with in the De Subtilitate. The characteristic most strongly marked in the later book is the increased eagerness with which he plunges into the investigation of certain forces, which he professes to appreciate as lying beyond Nature, and incapable of scientific verification in the modern sense, and the fabled manifestations of the same. He loses no opportunity of trying to peer behind the curtain, and of seeking—honestly enough—to formulate those various pseudo-sciences, politely called occult, which have now fallen into ridicule and disrepute with all except the charlatan and the dupe, who are always with us. Where he occupies in the De Subtilitate one page in considering those things which lie outside Nature—demons, ghosts, incantations, succubi, incubi, divinations, and such like—he spends ten in the De Varietate over kindred subjects. There is a wonderful story[121] told by his father of a ghost or demon which he saw in his youth while he was a scholar in the house of Giovanni Resta at Pavia. He searches the pages of Hector Boethius, Nicolaus Donis, Rugerus, Petrus Toletus, Leo Africanus, and other chroniclers of the marvellous, for tales of witchcraft, prodigies, and monstrous men and beasts, and devotes a whole chapter to chiromancy,[122] a subject with which he had occupied his plenteous leisure when he was waiting for patients at Sacco. The diagram of the human hand given by him does not differ greatly from that of the contemporary hand-books of the "Art," and the leading lines are just the same. The heavenly bodies are as potent here as in Horoscopy. The thumb is given to Mars, the index finger to Jupiter, the middle finger to Saturn, the ring finger to the Sun, and the little finger to Venus. Each finger-joint has its name, the lowest being called the procondyle, the middle the condyle, and the upper the metacondyle. He passes briefly over as lines of little import, the via combusta and the Cingulus Orionis, but lays some stress on the character of the nails and the knitting together of the hand, declaring that hands which can be bent easily backward denote effeminacy or a rapacious spirit. He teaches that lines are most abundant in the hands of children, on account of the tenderness of the skin, and of old men on account of the dryness, a statement which might suggest the theory that lines come into existence through the opening and closing of the hand. But the adoption of this view would have proved more disastrous to chiromancy than ridicule or serious criticism; so he straightway finds an explanation for this fact in the postulate that lines in young people's hands speak as to the future, and in old men's as to the past. Later he goes on to affirm that lines in the hand cannot be treated as mere wrinkles arising from the folding of the skin, unless we are prepared to admit that wrinkled people are more humorous than others, alluding no doubt to the lines in the face caused by laughter, a proposition which does not seem altogether convincing or consequential, unless we also postulate that all humorous men laugh at every joke. There is a line in the hand which he calls the linea jecoraria, and the triangle formed by this and the linea vitæ and the linea cerebri, rules the disposition of the subject, due consideration being given to the acuteness or obtuseness of the angles of this triangle. Cardan seems to have based his treatise on one written by a certain Ruffus Ephesius, and it is without doubt one of the dullest portions of his work.[123]
It is almost certain that Cardan purposed to let the De Varietate come forth from the press immediately after the De Subtilitate, but before the MS. was ready, it came to pass that he was called to make that memorable journey to Scotland in order to find a remedy for the ailment which was troubling the Archbishop of St. Andrews, a journey which has given to Britons a special interest in his life and work. In dealing with the Cosmos in the De Subtilitate he had indeed made brief mention of Britain; but, writing then, he had no personal relations with either England or Scotland, or the people thereof; and, but for his subsequent visit, he would not have been able to set down in the pages of his second book so many interesting and suggestive notes of what he had seen and heard, and his ideas of the politics of the time. Again, if he had not been urged by the desire all men feel to read what others may have to say about places they have visited, it is not likely that he would have searched the volumes of Hector Boethius and other early writers for legends and stories of our island. Writing of Britain[124] in the De Subtilitate he had praised its delicate wool and its freedom from poisonous beasts: a land where the wolf had been exterminated, and where the sheep might roam unvexed by any beast more formidable than the fox. The inordinate breeding of rooks seems even in those days[125] to have led to a war of extermination against them, carried on upon a system akin to that which was waged against the sparrow in the memory of men yet living. But besides this one, he records, in the De Subtilitate, few facts concerning Britain. He quotes the instances of Duns Scotus and Suisset in support of the view that the barbarians are equal to the Italians in intellect,[126] and he likewise notices the use of a fertilizing earth—presumably marl—in agriculture,[127] and the longevity of the people, some of whom have reached their hundred and twentieth year.[128] The first notice of us in the De Varietate is in praise of our forestry, forasmuch as he remarked that the plane tree, which is almost unknown in Italy through neglect, thrives well in Scotland, he himself having seen specimens over thirty feet high growing in the garden of the Augustinian convent near Edinburgh. The lack of fruit in England he attributes rather to the violence of the wind than to the cold; but, in spite of our cruel skies, he was able to eat ripe plums in September, in a district close to the Scottish border. He bewails the absence of olives and nuts, and recommends the erection of garden-walls in order to help on the cultivation of the more delicate fruits.
In a conversation with the Archbishop of St. Andrews he was told that the King of Scots ruled over one hundred and sixty-one islands, that the people of the Shetland Islands lived for the most part on fish prepared by freezing or sun-drying or fire, and had no other wealth than the skins of beasts. Cardan pictures the Shetlanders of that time as leading an ideal life, unvexed by discord, war, or ambition, labouring in the summer for the needs of winter, worshipping Christ, visited only once a year by a priest from Orkney, who came over to baptize the children born within the last twelve months, and was remunerated by a tenth of the catch of fish. He speaks of the men of Orkney as a very lively, robust, and open-hearted crew, furnished with heads strong enough to defy drunkenness, even after swallowing draughts of the most potent wine. The land swarms with birds, and the sheep bring forth two or even three lambs at a time. The horses are a mean breed, and resemble asses both as to their size and their patience. Some one told him of a fish, often seen round about the islands, as big or even bigger than a horse, with a hide of marvellous toughness, and useful for the abundance of oil yielded by its carcase. He attributes the bodily strength of these northerners to the absence of four deleterious influences—drunkenness, care, heat, and dry air. Cardan seems to have been astonished at the wealth of precious stones he found in Scotland—dark blue stones, diamonds, and carbuncles[129]—"maxime juxta academiam Glaguensis oppidi in Gludisdalia regione," and he casts about to explain how it is that England produces nothing of the kind, but only silver and lead. He solves the question by laying down an axiom that the harder the environment, the harder the stone produced. The mountains of Scotland are both higher and presumably harder than those of England, hence the carbuncles.
He was evidently fascinated with the wealth of local legend and story which haunted the misty regions he visited. In dealing with demons and familiar spirits he cites the authority of Merlin, "whose fame is still great in England," and tells a story of a young woman living in the country of Mar.[130] This damsel was of noble family and very fair in person, but she displayed a great unwillingness to enter the marriage state. One day it was discovered that she was pregnant, and when the parents went to make inquisition for the seducer, the girl confessed that, both by day and night, a young man of surpassing beauty used to come and lie with her. Who he was and whence he came she knew not. They, though they gave little credit to her words, were informed by her handmaid, some three days afterwards, that the young man was once more with her; wherefore, having broken open the door, they entered, bearing lights and torches, and beheld, lying in their daughter's arms, a monster, fearsome and dreadful beyond human belief. All the neighbours ran quickly to behold the grisly sight, and amongst them a good priest, well acquainted with pagan rites. When he had come anear, and had said some verses of the Gospel of Saint John, the fiend vanished with a terrible noise, bearing away the roof of the chamber, and leaving the bed in flames. In three days' time the girl gave birth to a monstrous child, more hideous than anything heretofore seen in Scotland, wherefore the nurses, to keep off disgrace from the family, caused it to be burnt on a pile of wood. There is another story of a youth living about fourteen miles from Aberdeen, who was visited every night by a demon lady of wonderful loveliness, though he bolted and locked his chamber-door; but by fasting and praying and keeping his thoughts fixed on holy things he rid himself at last of the unclean spirit.[131] He quotes from Boethius the whole story of Macbeth,[132] and tells how "Duffus rex" languished and wasted under the malefic arts of certain witches who made an image of the king in wax and, by using various incantations, let the same melt slowly away before the fire. The unhappy king came near to die, but, as soon as these nefarious practices were discovered, the image was destroyed, whereupon the king was restored to health.[133]
When Cardan received the first letter from Scotland the manuscript of the De Varietate must have been ready or nearly ready for the printer; but, for some reason or other, he determined to postpone the publication of the work until he should have finished with the Archbishop, and took his manuscript with him when he set forth on his travels. In 1550 there came another break in Cardan's life as Professor at Pavia, the reason being the usual one of dearth of funds.[134] In 1551 he went back for a short time, but the storms of war were rising on all sides, and the luckless city of Pavia was in the very centre of the disturbance. The French once more crossed the Alps, pillaging and devastating the country, their ostensible mission being the vindication of the rights of Ottavio Farnese to the Duchy of Parma. Ottavio had quarrelled with Pope Julius III., who called upon the Emperor for assistance. War was declared, and Charles set to work to annex Parma and Piacenza as well to the Milanese. Cardan withdrew to Milan at the end of the year. Gian Battista had now completed his medical course, so there was now no reason why he should continue to live permanently at Pavia. Moreover at this juncture he seems to have been strongly moved to augment the fame which he had already won in Mathematics and Medicine by some great literary achievement, and he worked diligently with this object in view.[135]
At the beginning of November 1551, a letter came to him from Cassanate,[136] a Franco-Spanish physician, who was at that time in attendance upon the Archbishop of St. Andrews, requesting him to make the journey to Paris, and there to meet the Archbishop, who was suffering from an affection of the lungs. The fame of Cardan as a physician had spread as far as Scotland, and the Archbishop had set his heart on consulting him. Cassanate's letter is of prodigious length. After a diffuse exordium he proceeds to praise in somewhat fulsome terms the De Libris Propriis and the treatises De Sapientia[137] and De Consolatione, which had been given to him by a friend when he was studying at Toulouse in 1549. He had just read the De Subtilitate, and was inflamed with desire to become acquainted with everything which Cardan had ever written. But what struck Cassanate more than anything was a passage in the De Sapientia on a medical question, which he extracts and incorporates in his epistle. Cardan writes there: "But if my profession itself will not give me a living, nor open out an avenue to some other career, I must needs set my brains to work, to find therein something unknown hitherto, for the charm of novelty is unfailing, something which would prove of the highest utility in a particular case. In Milan, while I was fighting the battle against hostile prejudice, and was unable to earn enough to pay my way (so much harder is the lot of manifest than of hidden merit, and no man is honoured as a prophet in his own country), I brought to light much fresh knowledge, and worked my hardest at my art, for outside my art there was naught to be done. At last I discovered a cure for phthisis, which is also known as Phthœ, a disease for many centuries deemed incurable, and I healed many who are alive to this day as easily as I have cured the Gallicus morbus. I also discovered a cure for intercutaneous water in many who still survive. But in the matter of invention, Reason will be the leader, but Experiment the Master, the stimulating cause of work in others. If in any experiment there should seem to be an element of danger, let it be performed gently, and little by little."[138] It is not wonderful that the Archbishop, who doubtless heard all about Cardan's asserted cure of phthisis from Cassanate, should have been eager to submit his asthma to Cardan's skill. After acknowledging the deep debt of gratitude which he, in common with the whole human race, owed to Cardan in respect to the two discoveries aforesaid, Cassanate comes to the business in hand, to wit, the Archbishop's asthma. Not content with giving a most minute description of the symptoms, he furnishes Cardan also with a theory of the operations of the distemper. He writes: "The disease at first took the form of a distillation from the brain into the lungs, accompanied with hoarseness, which, with the help of the physician in attendance, was cured for a time, but the temperature of the brain continued unfavourable, being too cold and too moist, so that certain unhealthy humours were collected in the head and there remained, because the brain could neither assimilate its own nutriment, nor disperse the humours which arose from below, being weakened through its nutriment of pituitous blood. After an attack of this nature it always happened that, whenever the body was filled with any particular matter, which, in the form of substance, or vapour, or quality, might invade the brain, a fresh attack would certainly arise, in the form of a fresh flow of the same humour down to the lungs. Moreover these attacks were found to agree almost exactly with the conjunctions and oppositions of the moon."[139]
Cassanate goes on to say that his patient had proved somewhat intractable, refusing occasionally to have anything to do with his medical attendants, and that real danger was impending owing to the flow of humour having become chronic. Fortunately this humour was not acrid or salt; if it were, phthisis must at once supervene. But the Archbishop's lungs were becoming more and more clogged with phlegm, and a stronger effort of coughing was necessary to clear them. Latterly much of the thick phlegm had adhered to the lungs, and consequently the difficulty of breathing was great. Cassanate declares that he had been able to do no more than to keep the Archbishop alive, and he fears no one would be able to work a complete cure, seeing that the air of Scotland is so moist and salt, and that the Archbishop is almost worried to death by the affairs of State. He next urges Cardan to consent to meet the Archbishop in Paris, a city in which learning of all sorts flourishes exceedingly, the nurse of many great philosophers, and one in which Cardan would assuredly meet the honour and reverence which is his due. The Archbishop's offer was indeed magnificent in its terms. Funds would be provided generous enough to allow the physician to travel post the whole of the journey, and the goodwill of all the rulers of the states en route would be enlisted in his favour. Cassanate finishes by fixing the end of January 1552 as a convenient date for the rendezvous in Paris, and, as time and place accorded with Cardan's wishes, he wrote to Cassanate accepting the offer.
The Archbishop of St. Andrews was John Hamilton, the illegitimate brother of James, Earl of Arran, who had been chosen Regent of the kingdom after the death of James V. at Flodden, and the bar sinister, in this case as in many others, was the ensign of a courage and talent and resource in which the lawful offspring was conspicuously wanting. Any student taking a cursory glance at the epoch of violence and complicated intrigue which marked the infancy of Mary of Scotland, may well be astonished that a man so weak and vain and incompetent as James Hamilton—albeit his footing was made more secure by his position as the Queen's heir-presumptive—should have held possession of his high dignities so long as he did. Alternately the tool of France and of England, he would one day cause his great rival Cardinal Beatoun to be proclaimed an enemy of his country, and the next would meet him amicably and adopt his policy. After becoming the partisan of Henry VIII. and the foe of Rome, he finally put the coping-stone to his inconsistencies by becoming a convert to Catholicism in 1543. But in spite of his indolence and weakness, he was still Regent of Scotland, when his brother, the Archbishop, was seized with that attack of periodic asthma which threatened to change vitally the course of Scottish politics. A very slight study of contemporary records will show that Arran had been largely, if not entirely, indebted to the distinguished talents and to the ambition of his brother for his continued tenure of the chief power of the State. If confirmation of this view be needed, it will be found in the fact that, as soon as the Archbishop was confined to a sick-room, Mary of Guise, the Queen Mother, supported by her brothers in France and by the Catholic party at home, began to undermine the Regent's position by intrigue, and ultimately, partly by coaxing, partly by threats, won from him a promise to surrender his power into her hands.