knowledge; his reasoning was scientific and practical, his demonstrations lucid and convincing, and he must be gratefully remembered by hundreds of medical officers who owe much of their knowledge of disease, its causes and results, to his teaching.

A friend and colleague of Dr. Aitken writes:-"In the post-mortem room he was facile princeps. I never saw any one to compare with him at work of this kind. It was a lesson none could forget to see him conduct a post-mortem and hear his exposition of what he saw. He had great powers of work, and was a student in his own way all his life. His book held the field for many years as a student's textbook." And, again, "He was scrupulously honest as a writer; strove always to give every man his due."

Aitken's services to medicine were not restricted to his work as a teacher and examiner. He made many contributions of importance to the literature of medicine, and to that branch of it which he had made peculiarly his own-pathology. Up to the last he continued his labours, and at the time of his last illness was engaged in the publication of a descriptive catalogue of the Museum of Pathology now located at Netley. It is to be hoped that some competent successor will undertake to carry on and complete the work thus unfortunately interrupted.

It is sufficient to name the chief of his writings to indicate the debt due to this great pathologist, and to show how earnestly he laboured to contribute his share of knowledge to the common stock. The following are the best known :

"On Inflammatory Effusions into the Substance of the Lungs as modified by Contagious Fevers," 1849. (2) "Contributions to Pathology." (3) "On the Pathology of the Diseases of the Troops in the East during the Russian War, 1855-56," in conjunction with Dr. R. D. Lyons. (4) "On the Diseases of the Troops in the East during the Russian War, and on the Climate of Scutari, on the Bosphorus," 1857. (5) "Medical History of War with Russia," 1857. (6) "On the Persistent and Pernicious Influence of the Residence in Bulgaria on the Subsequent Health of the British Troops in the Crimea." (7) "On conducting Post-mortem Examinations at Coroners' Inquests," 1857. (8, 9, 10) "On the Pathological Connexions and Relations of Epidemic Diseases in Man and the Lower Animals, with special reference to the relationship between the health of man and the condition of his food," 1857. (11) “Analytical Review of the Transactions of the Medico-Chirurgical Society of London, vol. xii," 1859. (12) "Critical and Analytical Review of Recent Works on the Pathology of Vaccination, and its Protective Influence from Small-pox," 1857. (13) "Analytical and Critical Review of the First Decennium of the Pathological Society of London," 1858. (14) "Handbook of the Science and Practice of

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Medicine," 1858 [this has reached its seventh edition]. (15) “On the Growth of the Recruit and the Young Soldier" [now in its second edition]. (16) "On the Doctrine of Evolution in its Application to Pathology," 1885-86. (17) "On the Animal Alkaloids."

Aitken was a man of somewhat reserved and reticent speech, but what he said was pregnant with science and common-sense. He was of a most kindly, genial nature, loyal to his profession, devoted to his friends, and just to all. His personal character endeared him to every one. His frank, straight forward mode of expressing his opinions, tempered as they were by sound judgment and discretion, made him respected and esteemed, and contributed, in no small measure, to the formation of the reputation of one of that small but remarkable group of men to whom the great Army Medical School owes its rise, development, and success. Regretted universally by friends and colleagues, it is in the great School of Military Medicine, which owes him so much, that his loss will be most keenly felt.

His merits have not escaped some recognition. He was made a Fellow of the Royal Society in 1873. In 1887 he received the honour of knighthood. The Universities of Edinburgh and Glasgow, in 1838, conferred on him the degree of LL.D., whilst on the walls of the ante-room at Netley is an excellent portrait presented by his numerous friends, admirers, and pupils.

May his memory long continue to influence coming generations of medical officers in the School he loved so well!

J. F.

THOMAS HAWKSLEY, civil engineer, was born at Nottingham in 1807. He was educated as an architect and surveyor, but, having an inclination for mechanical pursuits, he studied diligently the sciences necessary to enable him to practise as a civil engineer, and with such success that in 1830 he undertook the construction of new waterworks for his native town. The knowledge and skill he exhibited in these works led to more practice in other districts, and in 1852 he removed his offices to London, where, before long, he took the highest rank in that branch of engineering having to do with water and gas supply, and with drainage and hydraulic works generally.

Mr. Hawksley was accustomed to say that he had constructed above 150 waterworks, many of the largest character; and that there were no important towns in Great Britain, and indeed very few great cities in the civilised world, in regard to which he had not been professionally consulted in some way or other. He is especially cele brated for having been the first to suggest and to carry into practice the system of "constant service" in water supply, which combined the most free and ample provision of water with the almost perfect

repression of waste, and with greatly improved sanitary conditions. The introduction of the system involved many difficulties and much opposition; but he always spoke of his success in it with great satisfaction and pride.

It must not be supposed that municipal engineering in the days of Mr. Hawksley's early practice meant simply building and mechanical operations. It involved often grave and novel considerations, and it was his merit to bring to bear upon them accurate scientific knowledge and careful study. The lucid and skilful manner in which he was in the habit of applying scientific principles to his professional practice was well known to engineers generally: "Mr. Hawksley's formulæ," "Mr. Hawksley's data," "Mr. Hawksley's general results," and so on, were continually adopted as familiar guides by his professional brethren, and were quoted as authorities against which there could be no appeal.

On one occasion he had to advise on the drainage of one of the largest towns in the kingdom, and a question arose involving some artificial hydraulic conditions of much greater magnitude than usual. Doubts were expressed as to the feasibility of his scheme, but Mr. Hawksley had a strong impression that the ordinary rules, based on comparatively small experiments, did not apply. He accordingly examined the question thoroughly, bringing to his aid certain recent hydraulic researches by eminent French mathematicians; and, with the help of the writer of this notice, he succeeded in showing the practicability of the plan by an amount of scientific evidence which, while it was perfectly new, was absolutely incontrovertible.

Mr. Hawksley was President of the Institution of Civil Engineers for the years 1872 and 1873, and of the Institution of Mechanical Engineers in 1876 and 1877.

In 1876 he was elected President of the National Association of Social Science, holding their meeting at Liverpool, when he gave an address especially remarkable for its happy application of statistics to sanitation. He was a clever and lucid writer, and his keen appreciation of scientific reasoning gave great weight to his opinions.

He was elected a Fellow of the Royal Society on the 6th of June, 1878, as being "especially distinguished for the application of Science to Hydraulic Engineering."

Mr. Hawksley was blessed with a constitution which prolonged his life and energy much beyond the ordinary lot of man. In the beginning of September, 1893, sixty-three years after his appointment as engineer to the Nottingham Waterworks, he undertook one of his customary tours of inspection of his works in progress in distant parts of England; but a fortnight afterwards he was attacked by a sudden and formidable disease, which his aged frame was not able to resist, and he died at his residence at Kensington on the 23rd.

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JOHN TYNDALL was born at Leighlin Bridge, near Carlow, in Ireland, on the 21st of August, 1820, and the early years of his life, up to the age of 19, were spent in this village, where he received instruction in the school of one John Conwill, who seems to have been a man of somewhat original and independent character. Not much is known of the subjects taught to Tyndall in this school, but he certainly acquired there a very thorough knowledge of elementary mathematics and geometry. Classics did not form part of the curriculum; for, at the age of 27 he was still unacquainted with the Latin language.

On leaving school at the age of 19, he obtained an appointment as assistant in the division of the Ordnance Survey at Carlow. About two years later, Tyndall came to England and attached himself to a Manchester firm of railway engineers, by whom he was employed in levelling, surveying, and making out plans and estimates in accordance with the rules of the Board of Trade. In this occupation he seems to have spent about five or six years of his life, and the experience thus gained during the so-called railway mania, doubtless, contributed in no small degree to his subsequent love of pursuits which necessitated accuracy of measurement and logical reasoning.

In the year 1847, he became acquainted with the late George Edmondson, who, at that time, was endeavouring to introduce into a large private boys' school at Preston instruction in the elements of experimental science. In the spring of that year Mr. Edmondson undertook, at the instigation of the Socialists who were under the leadership of Robert Owen, to transform their abortive establishment, "Harmony Hall," into a school and agricultural college, which received the name of "Queenwood College." Here, for the first time in an English school, experimental science was practically taught in the laboratory and in the field, and Tyndall, although at considerable pecuniary loss to himself, was easily persuaded to become a teacher of mathematics and surveying in this new establishment, being chiefly influenced, as he himself declared, by the opportunity afforded him of working in a chemical laboratory.

Tyndall remained at Queenwood College, where he had an enthusiastic class of pupils who were greatly attached to him, until the autumn of 1848, when he accompanied the writer to Marburg, there to continue his study of chemistry in the laboratory of Professor Bunsen. He did not, however, confine his attention to chemistry, but attended also the classes of the professors of mathematics and physics. Indeed, by far the larger portion of his time, during his first year at Marburg, was spent in mathematical work.

In the year 1850 he graduated in the Philosophical Faculty, taking mathematics for his principal subject in viva voce examination, and, for the two subsidiary subjects, chemistry and physics. Before

admission to examination at Marburg, it is essential to present to the Faculty a memoir on some original investigation made by the candidate. Tyndall's dissertation was entitled, "Die Schraubenflaeche mit Geneigter Erzeugungs-Linie und die Bedingungen des Gleichgewichts für solche Schrauben," which shows that, at that time, Tyndall's knowledge of mathematics was superior to his acquirements in chemistry and physics.

Physical Researches.-About this time there came to Marburg, as extraordinary professor, an enthusiastic young physicist, afterwards well known as Professor Knoblauch, who exercised a profound influence upon Tyndall, and who was probably the main cause of the latter devoting himself, for the future, chiefly to physical science. It was in conjunction with Knoblauch that Tyndall made his first physical investigation, the results of which were published in the year 1850 with the title "On the Deportment of Crystallised Bodies between the Poles of a Magnet."

From

During the next thirty-three years Tyndall published 135 papers, or at the average rate of rather more than 4 per annum. Marburg he migrated to Berlin, where he worked for about a year in Magnus's laboratory, continuing his researches on diamagnetism and magne-crystallic action, finally returning to England about the end of the year 1851 or the beginning of 1852. He took up his quarters again at Queenwood College, not as a teacher, but as a guest, awaiting the advent of some suitable appointment. At this time there was no physical laboratory in England, and consequently no chair of experimental physics. There was, it is true, a professor of physics at Owens College, Manchester, but the chair was occupied by a Cambridge wrangler, who, though an able mathematician, probably never made an experiment in his life. Tyndall had to wait until 1853, having in the meantime been an unsuccessful candidate for a professorship at Toronto.

On February 11th, 1853, he delivered, at the Royal Institution, his first public lecture "On the Influence of Material Aggregation upon the Manifestation of Force." This lecture, although of such an abstruse character, took his audience-mostly popular as it was-by storm. It concluded with the following graceful tribute to Faraday :

"This evening's discourse is, in some measure, connected with this locality; and, thinking thus, am led to inquire wherein the true value of a scientific discovery consists? Not in its immediate results alone, but in the prospect which it opens to intellectual activity, in the hopes that it excites, in the vigour which it awakens. The discovery which led to the results brought before you to-night was of this character. That magnet (pointing to the large electro-magnet at the Royal Institution) was the physical birthplace of these results; and if they possess any value they are to be regarded as the returning