between the beginning and end of the parody. While the ass breathed through the flute, it gave only its own sweet tones; but he was so delighted with what he had done, that he concluded by breaking out into his own natural bray.

At the latter end of 1796, Dr Beddoes published the fourth and fifth parts of his "Considerations on Factitious Airs," which, beside much mis cellaneous matter, not directly connected with the main topic of the book, contained the first proposal made in England for curing syphilis with nitric acid. The efficacy of mercury in this disease was believed to depend on the oxygen with which it was combined, and it was supposed that any other substance, which would part with oxygen as readily to the constitution, would be equally serviceable. With this view, the nitric acid was exhibited by Mr Scott, of Bombay, whose reports, containing an account of the first experimental attempt to realize this idea, were included in the Considerations on Facti tious Airs. The remedy excited much expectation, but its more extended employment has shown its feeble and imperfect virtues.

Notwithstanding Beddoes had written so much on the employment of artificial gases in disease, he had made but little use of them in his own practice. Patients had never yet been admitted at the Pneumatic Institution, owing to the deficiency of the subscriptions; and, in order to accelerate the fulfilment of the scheme, he published, early in 1797, suggestions toward setting on foot the projected establishment for ascertaining the powers of factitious airs in medicine. The subscription, however, would have been still inadequate to its purpose, if the late Mr T. Wedge

wood had not offered 1000l. to secure the immediate execution of the plan, wisely observing, that "it was worth while to expend the sum subscribed, in order to assure us that elastic fluids would not be serviceable as medicines." This liberal offer removed all pecuniary obstacles, and in 1798 the institution was opened for the reception of patients. Dr Beddoes, however, found that he required some assistance in the preparation of the airs. His friend Mr Giddy had become acquainted with a young man who was educating as a country surgeon in Cornwall, and whose talents and scientific zeal had attracted the notice of the neighbourhood. Mr Giddy was delighted with the modesty and genius of his young acquaintance, and persuaded him to transmit to Dr Beddoes a letter containing some thoughts on the French theory of caloric, and some experiments which he had made, proving that heat was not a substance. Bed does instantly saw the merits of the mind which was presented to his notice, and he invited him to become his assistant at the Pneumatic Institution. The invitation was accepted, and Mr Davy removed to Bristol. The correct discrimination displayed in this early appreciation of Mr Davy's ge nius, has since been abundantly proved by the discoveries which he has achieved, and the fame which he has won,-discoveries so brilliant, and fame so truly enviable, as to have afforded a reasonable ground for the sarcastic observation, that the best discovery Dr Beddoes ever made was Davy.

The trials of the artificial airs at the Pneumatic Institution led to the following results :-Priestly had said, that breathing pure oxygen air made him feel light and cheerful. M. Cail

lens, a French physician, is said by Chaptal to have made his phthisical patients breathe it with great advantage. Fourcroy, on the contrary, found that it increased the fever and arterial action, and was highly injurious. Dr Ewart, of Bath, caused two consumptive patients to breathe an atmosphere which contained a quantity of carbonic acid gas with considerable advantage. Pilatre de Rosier himself breathed hydrogen or inflammable air, and as he was expiring it from his mouth set it on fire, so as to exhibit a specimen of a live gas lamp. A mixture of oxygen and hydrogen, when set on fire, is well known by chemists to explode with considerable violence; nevertheless this fearless philosopher inhaled a mixture of these airs, and set fire to them as they issued from his mouth; the explosion was violent, and he thought had knocked out his teeth. It may be breathed during several inspirations without injury, and is returned from the lungs nearly unchanged. Such was the state of knowledge concerning the influence of artificial airs when taken into the lungs, before the foundation of the Pneumatic Institution; here it was found that an atmosphere containing an additional quantity of oxygen in some instances cured the white swelling of the knee joint, and healed old ulcers rapidly; it was useful in chlorosis, hypochondriacis melancholia; it relieved the difficult breathing in asthma, hydrothorax, and other diseases; it was useful in effects of over doses of opium, in paralysis, simple debility, and even in leprosy and other obstinate cutaneous diseases. In short, it appears to be a powerful excitant, to have been useful in diseases of defective, and injurious in those of excessive action. Carbonic acid also was tried

at the Pneumatic Institution; Mr. Davy attempted to breathe it undiluted, but as soon as it arrived at the top of the windpipe, the epiglottis closed with painful sensation, and prevented its entering the lungs; dilu. ted with common air, it was found to relieve phthisis, agreeably to the experience of Dr Ewart. The inspiration of hydrogen produced vertigo, and a consequent retardation of the circulation; it was useful in catarrh, phthisis, and sometimes in asthma; it appeared also to be in some degree an anodyne. The most powerful artificial air, however, that has yet been respired, is made by a mixture of carbonic and hydrogen gas, (the bydro carbonate;) Mr Davy ventured to inhale it in its pure undiluted state: "The first inspiration produced a sort of numbness and loss of feeling in the chest and about the pectoral muscles; after the second, he lost all power of perceiving external things, and had no distinct sensation except terrible oppression on the chest. During the third inspiration, he seemed to himself to be sinking into annihilation, and had just power enough to drop the mouth-piece from his unclosed lips. A short interval passed, during which he respired common air before the objects about him were distinguishable. On recollecting himself, he faintly articulated, 'I do not think I shall die.' The pulse was threadlike, and beat with excessive quickness. In less than a minute he was able to walk, but nausea, vertigo, and an excruciating headache returned at intervals during the remainder of the day, and he continued feeble and exhausted till the succeeding evening.” Such was the effect the undiluted hydro-carbonate produced on the healthy constitution. In a less concen trated form, it is said to have been

tion of Consumption, was to show the climates and the classes of people which were exempt from consumption. "Could a doctrine of exemption," says he, "be established, we should only have to adopt as nearly as possible into our own conduct the circumstances on which exemption depends; on the other hand, if it shall appear that there are whole descriptions of persons peculiarly liable to the complaint, we may stand a chance of collecting from their history a lesson equally valuable on the habits to be avoided." The facts contained in the essay are many of them of infinite value, and cannot be too often presented to our minds; butchers, who eat much meat, and who are frequently exposed to the effluvia of putrid animal substances, makers of catgut and stable boys, who in the latter circumstance resemble butchers, fisherwomen and sailors, whose laborious occupation in the open air generates robustness of constitution, are almost entirely exempt from this disease; on the contrary, tailors and shoemakers, whose employments require bodily inactivity, and are carried on in close rooms, stone-cutters, who are continually in haling into their lungs the fine particles rubbed off during the division of the stone,-needle-pointers, weavers, spinners, carpet-manufacturers, whose employments comprehend both the evils of confinement and inactivity, and the inhalation of foreign substances, are the most common victims to consumption. The practical inference that is drawn from these facts is, that we should imitate those habits of the exempted classes on which their exemption appears to depend; that we should endeavour, by the use of animal food, and strong and frequent exercise in the open air, to ge

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nerate that robustness of constitution which prevents the access of consump tion. Beddoes conducted this inquiry with admirable ability, and there is much reason for believing that the search after a preventative, rather than a cure, for this disease, is still the most promising means of encroaching on its fatality. Among the climates within our reach, Dr Beddoes prefers Egypt, Bengal, and the West Indies; he expresses doubts about the utility of Lisbon, Italy, and Madeira, and conjectures that the benefit which is sometimes experienced by those who go to these places is attributable rather to the voyage than to the climate. Lisbon is now much less frequently resorted to by patients than formerly; and the tombstones of strangers in the churchyards of Madeira afford but unfavourable testimony to the healing influence of its climate. This essay contains his first proposal for the employment of foxglove as a remedy for consumption; it was already known to have the power of producing the absorption and expul sion of dropsical fluids, and the recovery of some cases of consumption during its use led him to hope, with his usual intensity of belief, that it was able to effect the absorption and expulsion of those minute tumours or tubercles in the substance of the lungs, with which consumption in its worst form commences.

The next object on which he expended his activity and zeal, was to ascertain the virtues of the nitric acid, as a remedy for syphilis: he published several volumes of reports of his own trials, as well as those of his medical friends. On this subject, his most mature opinion appears to be contained in a letter, in which he says that nitrous acid seems to fail in more syphilitic cases than mercury; but it