On returning from Caithness to Glasgow, Macnish made a journey to Paris, where he resided a year, for the double purpose of recruiting his constitution and continuing his medical education. In the French capital, among other opportunities of improving his taste, he frequented the Louvre, while its vast collection of the treasures of art, the spoils of conquered nations, were as yet unreclaimed; and here he learned to appreciate the beauties of painting and sculpture, without expressing his emotions in that artistic phraseology which is too often made the cloak of ignorant pretension. But of all places in Paris, the cemetery of Pere-la-Chaise, that city of the dead, became his favourite resort; and it was there that, in all likelihood, he increased that love of strange musing and mysticism which he had commenced in Caithness, and among the second-sighted Highlanders. On coming home he became assistant to his father, and completed his medical education at the university of Glasgow, where he took out his diploma of surgeon in 1825. His thesis which he delivered on this occasion, was an essay on the Anatomy of Drunkenness, which he afterwards expanded into his well-known work of the same title.

Before this period, however, Macnish had written articles, both in prose and verse, for the "Literary Melange," and for the "Emmet," periodicals of the Glasgow press. In 1822, also, he sent two productions to Constable’s "Edinburgh Magazine," the one entitled "Macvurich the Murderer," and the other, "The Dream Confirmed." Both were incidents which he had learned in the Highlands, and expanded into regular stories. But in 1825, a more popular and lasting field was opened to him in "Blackwood’s Magazine," of which he afterwards became one of the most distinguished contributors. His first contribution to this periodical, was his tale entitled "The Metempsychosis;" and he was encouraged to persevere from its being published in the monthly number as the leading article. This was no small distinction; for it will be remembered by the admirers of this most famed of magazines, that at the period we mention, it was in no want of highly talented correspondents. During the same year were inserted his "Man with the Nose," and the "Barber of Gottingen;" and on the following, the "Adventures of Colonel O’Shaughnessy," and "Who can it be?" articles whose classical style and rich, racy, original humour, arrested the attention of Ebony’s readers, who at this time might well be called the reading public, and raised the question of loud and general interest, Who is this "Modern Pythagorean?" In 1827, while Macnish was employed in these fugitive but important literary avocations, he was introduced by Mr. Blackwood to Dr. Moir, ever after his fast friend, who loved him like a brother, and lived to commemorate his worth.

It was not only in prose but in verse that Macnish excelled, and had he devoted himself to the Delilah of poetry, we doubt not that he would have been still more highly distinguished in this department of intellectual excellence, than he was as a prose writer of essays and tales. But already the field of the Muses had been so over-trodden and be-mired, that the best of our bards had escaped from it into the more ample and diversified regions of prose—Scott, Coleridge, Southey, and Moore, who were a-weary of having their kibes trode upon and grazed by the eager ambitious toes of awkward followers and imitators. Macnish, however, had been wont to express his deeper feelings in verse; and an event in 1827 called from him more than one mournful lyric of domestic sorrow. This was the death of his youngest sister, Christian, a child only ten years old, who was drowned on the banks of the Clyde near Glasgow, while crossing a plank laid athwart a small arm of the river.

The life of a man who devotes himself to the settled profession of a physician, and the peaceful occupations of authorship, presents few materials for the biographer. As a physician, indeed, we have little to say of Macnish, except that his career in this capacity was of even tenor, and was attended with a fair proportion of profit and success in his native city of Glasgow. In his literary capacity, every moment of spare time seems to have been fully occupied; and the articles which he contributed, both in prose and verse, not only to "Blackwood’s Magazine," but also to Frazer’s, and other less distinguished periodicals, obtained a prominent place in that species of light literature, and made the good folks of Glasgow justly proud of their fellow-citizen. These productions it is the less necessary to particularize, as they have been published in a compact volume under the editorship of his biographer, Delta. It may be merely mentioned in passing, that they are all more or less distinguished by a lively creative fancy, and chaste subdued classical style, reminding us more of the best writers of the Addison and Goldsmith periods, than the slashing, outré, and abrupt, though sparkling tales and essays that form the staple of our modern periodical writing. Among the happiest of these attempts of Macnish, we may particularly specify the "Metempsychosis," an "Execution at Paris," a "Night near Monte Video," and "A Vision of Robert Bruce." Still, Macnish might soon have been forgot by the magazine-reading public, had he not established his literary reputation upon a more secure basis; and it is by his "Anatomy of Drunkenness" and "Philosophy of Sleep," two able and substantial treatises, and his "Book of Aphorisms," that he is now best known and estimated.

The first of these works, which Macnish commenced before he had reached the age of twenty, and during his toilsome sojourn in Caithness, was the fruit of much reading and research, aided, perhaps, occasionally by the practical illustrations which he witnessed among the inhabitants of that whisky-smuggling county. Afterwards, he matured it into a thesis, which he read before the Medical Faculty in 1825, when he took out his degree, and published it in 1827 in a thin octavo of fifty-six pages. The subject was comparatively an untrodden field, as hitherto the vice of drunkenness had been rather analyzed by the divine and moralist, than anatomized by the surgeon. The novelty of such a work, and the felicity of his style and mode of illustration, excited a deeper interest among the readers than generally falls to theses, the most neglected of all literary productions, so that Macnish was encouraged to prosecute his inquiries. The result was, that the subject grew and improved upon his hands, while each edition was more popular than its predecessor, until, in 1834, a fifth edition of the "Anatomy of Drunkenness" was published by its author. Such success upon so unpromising a theme, was one of those triumphs which only true genius can accomplish. In this treatise he contemplates the vice in its physiological character, and writes like a learned physician on its origin, growth, and effects upon the constitution. He then expatiates upon its moral character, and illustrates with fearful power, but yet with the utmost patience and gentleness, the influence of this pernicious habit upon the intellectual and moral organization of its victim. And finally, knowing that all this is not enough, and that people will get drunk in spite of every dissuasive, he shows them in what way this crime may be committed in its least odious form, and with the smallest harm, upon the same benevolent principle that he would have applied the stomach-pump to those who had refused to be benefited, either by his warnings or instructions. His next work, the "Philosophy of Sleep," although of a more metaphysical character, fully sustained the reputation which his "Anatomy" had acquired, and rapidly passed into a second edition. These works not only obtained a wide popularity both in Scotland and England, but in America, where they were republished; they were also translated into the French and German languages, an honour exclusively accorded to philosophical treatises that possess unquestionable merit.

In 1833, Macnish published his "Book of Aphorisms." This little work, which is now almost forgotten, consisted of some fifty dozen fag-ends and quaint remarks, in the fashion of Rochefoucalt, or rather of Lord Bacon, but without pretending to soar to the eminence of these illustrious models. It was thought, however, a clever work in its day, among the circle to which it was limited. Another literary task which he executed, was an "Introduction to Phrenology," which he published in 1835. A second edition of this volume, which he had carefully prepared for publication, appeared two years after—but by this time Macnish had finished his appointed round of labour, and was beyond the reach of criticism; and this event, as well as a just appreciation of his character, was so well expressed in the "Phrenological Journal," in giving a review of the work itself, that we cannot refrain from quoting it, as a fitting close to this brief narrative:—

"This work appears breathing with life, spirit, and observation, as if its author were himself ushering it into the world. There is no indication within it, or announcement about it, that would lead the reader to believe that the mind which had conceived it had fled, and that the hand which had written it was cold in death; yet such are the facts! The work was just completed, and the last sheets of the appendix prepared for the press, when, in the beginning of January, 1837, the gifted author was seized with influenza, which speedily degenerated into typhus fever, and on the fourteenth day after the attack, he died. One of the distinguishing characteristics of Mr. Macnish’s mind was vivacity. Whether he gave way to ridicule and sarcasm, of which he was a master; or to fancy, with which he was brilliantly endowed; or to tenderness and affection, which he felt strongly, and could touchingly express; there was always a spring of life about him that vivified his pages, and animated and delighted his readers. This quality abounds in every page of the present work, and invests it with a new and extraordinary interest, when we regard it as the last words of a talented intellect now in the grave."