stephen hales - university of oregon

STEPHEN HALES*(1677-1761)

By G. E. BURGETPORTLAND, ORE.

S1 TEPHEN HALES was born at Bekes-bourne in Kent, September 7, 1677,the sixth son of Thomas and Mary

L Hales. Only meager information isobtainable in regard to his early life andtraining. In 1696, at the age of nineteen,he entered Bennet College, Cambridge.Although we have no definite record wemay assume that he applied himself ear-nestly to the study of religion and naturalphilosophy. He took a Bachelor of Artsdegree and was elected to a fellowshipabout 1702. In 1 70.3 he was granted aMaster of Arts degree. William Stukeley(1687-1765) afterwards M.D., F.R.S., wentto the college in 1 704. A friendship arosebetween him and Hales although Haleswas Stukeley's senior by ten years. FromFrancis Darwin we learn that these twocollege friends roamed the surroundingcountry together. Hales carried an often-thumbed copy of Ray's "Catalogue ofPlants." Everything from fossils to butter-flies was eagerly studied by the youngphilosophers. They dissected frogs, dogsand other animals together. John FrancisVigani (1650-1 7 12) who became the firstprofessor of chemistry at Cambridge in

* Read before the University of Oregon MedicalHistory Club, Portland, Ore., November 21, 1924.

Reprinted from the June, 1 9 2 5 issue of ANNALS OF MEDI-CAL. HISTORY, Vol. VII, No. 2, pages I 09-T 16.

Copyright, 1925.

2 Annals of Medical History

1703, seems to have attracted them. In aroom at Trinity College, the laboratory ofSir Isaac Newton, they repaired to repeatsome of Boyle's experiments and to watchthe demonstrations of Vigani. They pre-pared various substances, "some of use,some of curiosity." Hales studied astronomy.He knew well the Newtonian System.

While yet in college he constructed amachine of brass to show the movements ofall the planets. After having been in collegesome twelve years (16 96-1 708-9) we nexthear of him being made perpetual curateof Teddington, about 171 o. He took ordersand in 1711 became a Bachelor of Divinity.The next fifty years, until his death in

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3

1761, his home was in Teddington, Middle-sex, where Alexander Pope was a friend andneighbor and Peg Woffington one of hisparishioners.

He was married to Mary, daughter andheiress of Dr. Newce, rector of Halisharn,about the year 1719, the exact date isuncertain. Mary died two years later, 1721,

leaving no children. He never marriedagain.

Although we have none of his experi-mental data before 1719 there can be littledoubt that Hales was busy, as evidencedby the fact of his election to the RoyalSociety in 1718. In 1719 he reported to theSociety some recent experiments on theeffect of the sun's warmth in raising the sapin trees. For this he received the thanks ofthe Society with encouragement to continuethe research. This Hales did, reportingbefore the Society at different times, and inJune, 172_5, he gave an account of hisprogress in the form of a treatise. At therequest of the Society the work was pub-lished in 1727 under the title of "VegetableStaticks; or, an Account of Some StaticalExperiments on the Sap in Vegetables;being an essay towards a Natural HistoryVegetation. Also a specimen of an attemptto analyse the air by a great variety ofchymio-statical experiments, which wereread at several meetings of the RoyalSociety." The work was well received and asecond issue was published in 1731. TheSociety further honored him by making him


a member of the council, 1727. Hans Sloane(166o-1753 ) was at that time presidentof the Society. Upon the death of Sloane,1753, Hales was elected to the FrenchAcademy to fill his place.

"Vegetable Staticks," as the more elabo-rate title indicates, deals with the flowof sap in plants of various kinds and theeffect of moisture, temperature and typesof soil on the pressure under which saprises. The mercury manometer was usedfor these determinations, which were alwayscarefully and accurately worked out. Thebook contains many drawings which provethe ingenuity and care with which theexperiments were conducted. In all thereare 124 experiments, painstakingly recorded.They represent the original work on vege-table statics and opened at the time a newand fascinating field of plant physiology.Buffon (17o7–1788), the French naturalist,translated the work into French. Germanand Italian translations soon followed. Nodoubt this work early fell into the hands ofLinn& (1707-1778), then a young manpreparing his first work, "Systema Naturae"(1735). Sachs (1832-97), the well-knownGerman botanist, writes that of the studyof plant physiology that took place in theeighteenth century, the work of Haleswas the most original and the most impor-tant contribution. In honor of Hales, JohnEllis, whom Linnaeus termed "The brightstar of Natural History," named a newlydiscovered genus, Halesia.

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Intending at first only to make additionalobservations and experiments to the volumeon "Vegetable Staticks" he found in 1733that these had grown to the size of anothervolume. This he called "Haemastaticks,"or Volume it of the "Statical Essays."

The following paragraphs give an insightinto his purpose:

As the animal Body consists not only of awonderful texture of solid Parts, but also of alarge proportion of Fluids, which are continuallycirculating and flowing, thro' an inimitableEmbroidery of Blood-Vessels, and other incon-ceivably minute Canals: And as the healthyState of the Animal principally consists, in themaintaining of a due Equilibrium betweenthose Solids and Fluids; it has, ever since theimportant Discovery of the Circulation of theBlood, been looked upon as a matter well worththe inquiring into, to find the Force and Velocitywith which these Fluids are impelled; as a likelymeans to give a considerable Insight into theanimal Oeconomy.

It may not be improper here to take notice,that being about twenty-seven years since,reading the unsatisfactory conjectures of several,about the cause of muscular motion, it occurredto me, that by fixing tubes to the arteries oflive animals, I might find pretty nearly, whetherthe blood, by its mere hydraulic energy, couldhave a sufficient force, by dilating the fibres ofthe acting muscles, and thereby shorteningtheir lengths, to produce the great effects ofmuscular motion. And hence it was, as I men-tioned in the preface to Vol. 1, that I was insen-sibly led on from time to time into this large fieldof statical and other experiments.


He then proceeds to describe the classicalexperiments by which blood-pressure wasfirst measured:

In December I caused a mare to be tied downalive on her back; she was 14 hands high, andabout 14 years of age; had a fistula on herwithers, was neither very lean nor yet lusty;having laid open the left crural artery aboutthree inches from her belly, I inserted into it abrass pipe whose bore was one-sixth of an inchin diameter, and to that, by means of anotherbrass pipe which was fitly adapted to it, Ifixed a glass tube, of nearly the same diameter,which was nine feet in length: then untying theligature of the artery, the blood rose in the tube8 feet 3 inches perpendicular above the levelof the left ventricle of the heart; . . . whenit was at its full height, it would rise and fall atand after each pulse 2, 3 or 4 inches; . . .Then I took away the glass tube, and let theblood from the artery mount up in open air,when the greatest height of it's jet was not above2 feet.

I measured the blood as it ran out of theartery, and after each quart was run out, Irefixed the glass tube to the artery to see howmuch force the blood was abated; this I repeatedto the 8th quart, and then its force being muchabated, I applied the glass tube after each pinthad flowed out.

Three horses in all were used in thismanner, all of which were to have beenkilled as unfit for service. From one of thehorses he measured the blood lost bybleeding and after adding the probableamount in the large veins estimated the

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total' as five wine gallons, which he recog-nized as low, remarking that: "There isdoubtless considerably more, but it is noteasy to determine how much." The jugularpressure in one of the horses he found to betwelve inches when quiet, but this roseto fifty-two inches when the animalstruggled.

Experiments similar to these were doneon sheep and dogs and he says: "Whateverexperiment I principally intended to makeon any dog, I usually began with fixing atube first to the jugular vein and then tothe carotid artery."

He filled a number of hearts with meltedwax, later cutting away the tissue and esti-mating carefully the inner surface of theventricles. Knowing the volume and innersurface of the ventricles, the blood pressure,heart rate, the diameter of the aortic orificeand of the aorta itself, he calculated forhorses and various other animals includingman, the mean velocity of the blood in theaorta, the velocity of the systolic outputand the pressure sustained by the heartduring contraction. Although we now knowsuch an estimate would be more or lessinaccurate, nevertheless this carried thestudy of the circulatory system beyondHarvey's work and introduced the methodof quantitative investigation. Hales himselfappreciated the complexity of the situationregarding the velocity. He says:

Now this velocity is only the velocity ofthe blood at its first entering into the aorta, in the


time of the systole; in consequence of which theblood in the arteries, being forcibly propelled,with an accelerated impetus, thereby dilatesthe canal of the arteries, which begin to contractat the instant the systole ceases; by whichcurious artifice of nature the blood is carriedon to the finer capillaries, with an almost eventenor of velocity, in the same manner as thespouting water of some fire engines is contrivedto flow with a more even velocity, notwithstand-ing the alternate systoles and diastoles of therising and falling embolus or force . .

For tho' the velocity of the blood at its firstentrance into the aorta, depends on the propor-tion the area of its orifice bears to the quantitythrown into it at each systole, and also on thenumber of these systoles in a given time; yetthe real force of the blood in the arteries, dependsupon the proportion which the quantity of theblood thrown out of the left ventricle in a giventime, bears to the quantity which can pass thro'the capillary arteries, into the veins in that time.

He showed where the greatest resistanceto the blood existed by slitting a dog's gutopposite the mesentery and running warmwater through from the aorta. The time wasrecorded for a given amount of water tomake its escape in this manner. The vesselsin the mesentery were then cut and thetime for the escape of the same quantity ofwater was reduced from six to two minutes.By calculating, he found that this resistancemust be greater in the intact animal andaccounted for this difference by:

r. The greater fluidity of water as com-pared with blood.

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2. The absence of the back pressure of theveins in one case and its presence in the other.

3. The greater distensibility of the deadarteries.

4. In the case of the slit gut the fluid isno longer obliged to pass through the finecapillaries but runs out through the largervessels which have been severed.

He appreciated the fact that end pressuresare necessarily too high and devised ascheme by which the vessels were placedbetween two grooved pieces of wood whichwere later cemented together and to thevessels by means of warm pitch. Througha hole bored in one of the pieces of wood hepunctured the vessel, screwed a tube in thehole and allowed the blood to mount into it.

The effects of different substances uponthe caliber of the "capillary arteries"were studied. His own description is mostinteresting:

I took a young spaniel dog, opened his thoraxand abdomen, and having fixed a glass tubewhich was 4 and 12 feet high, to the descendingaorta, I then slit open his guts, from end to end.Then having poured blood warm water on them,and covered them with a folded cloth dipped inthe same water, warm water was poured intothe tunnel (attached to the tube) which whenit had subsided to a mark on the lower part ofthe glass tunnel 18 cubick inches of warm waterwere immediately poured in, out of a pot whichheld just that quantity; the time it was runningthrough the fine capillary arteries was measuredby a pendulum that beat seconds .

I 0 Annals of Medical History

I then poured on seven pots full of warmwater, the first of which gradually passed off in52 seconds, and the remaining six gradually inless time to the last, which passed in 46 seconds.

I then poured in five pots of common brandyor unrectified spirit of malt, the first of whichwas 68" in passing, the last 72".

I then poured in a pot of warm water whichwas 54" in passing.

Hence we see that brandy contracts the finecapillary arteries of the guts, and that watersoon relaxes them again.

A decoction of Peruvian bark contractedthe vessels. A decoction of camomel flowerscaused some constriction but not so muchas cinnamon-water, with which the constric-tion was very marked. Pyremont waterwas also very effective.

He thought that these experiments indi-cated the probable action of these sub-stances in the living body but understoodthat no such concentration was probablypresent in the living organism. His commentis:

'Tis probable that such things as constringethe vessels in any degree, do also proportionatelyincrease the force of the arterial blood andthereby invigorate the animal. But those whomuch accustom themselves to drink strongspirituous liquors, do thereby destroy the toneof the fibres of their vessels, by having them thusfrequently, suddenly contracted, and so soonrelaxed again; which makes them like the horse-leech, be ever longing after and thirsting formore and more thereby to regain the tensity oftheir too relaxed fibres.

STEPHEN HALES II

Man's blood-pressure he estimated asabout seven and one-half feet. Althoughthis is a little high we marvel that he wasable to approximate it so closely.

He decided to test further the theory thatmuscular contraction was brought aboutby force of the blood dilating the musclefibers. He soon felt convinced, however, thatits force was incapable of producing sogreat an effect as muscular motion. A morevigorous and active energy whose force isregulated by the nerves seemed to himnecessary. "But whether," he adds, "itbe confined in canals within the nerves oracts along their surfaces like electrical poweris not easy to determine."

Although his work indicated that he hada faint idea of the real process of digestion,his experiments were in no wise framed tothe end that Spallanzani's were, a halfcentury later. Hales, after making manyhydrostatic experiments on the stomach andintestine concluded:

So small a compressure can have very littleeffect in prompting the digestion of the aliments:which is therefore with good reason principallyattributed to the concurrence of several othercauses; such as mastication and comminutionwith the teeth, and mixture first with saliva(which is a leaven full of elastic air) and after-wards with the fluid, which is in plenty sepa-rated from the glands of the stomach.

Robert Boyle (1627-1691) made experi-ments with flames and animals in vacuo(166o), demonstrating that air is necessary

1 2 Annals of Medical History

for life as well as for combustion. RobertHooke (1635-1 703) in 1667 showed byblowing a stream of air through the exposedlung of an animal it could be kept alivewithout movement of chest or lungs. Bloodchanges were thus indicated. Two yearstater, 1669, Richard Lower of Cornwall(1631-169 1), to whom is ascribed the firstblood transfusion in the human (1668),injected dark venous blood into the insuf-flated lungs and as it became bright heconcluded it was by reason of its havingabsorbed something from the air. Mayow(1643-1679) termed this substance takenfrom the air nitro-aerial spirit of air.Malpighi (1628-1694) had demonstratedcapillary circulation in 1660 and publishedhis "De Pulmonibus," 1661, describinghow the trachea terminates in bronchialfilaments. These men were pioneers in thestudy of respiration and their findings donot represent the common knowledge orlack of knowledge of this subject. Haleswas still in doubt. He speaks of "plenty offresh air, that genuine cordial of life."He stands between these men and those ofthe next generation who contributed somuch to the development of our knowledgeof this subject, Joseph Black' (1728-1799),

1 He says in his remarks on fixed air: "For Ifound, that by blowing through a pipe into lime-water, or a solution of caustic alkali, the lime wasprecipitated, and the alkali was rendered mild. Iwas partly led to these experiments by some observa-tions of Dr. Hales, in which he says, that breathingthrough diaphragms of cloth dipped in alkaline

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Priestley (1733-1804), Laplace (174,9-1827),Lagrange (1 736-1813) and Spallanzani(1729-1799).

Hales had the exact amount of refrigera-tion action of the lungs calculated afterhaving determined the quantity of bloodpassing through the lungs per minute, theamount of air breathed during the sametime, and the difference in temperature ofthe inspired and expired air. This wasfound to be enough in two minutes to raiseall the blood of the body 0.101928 degrees.He describes carefully the circulation ofthe lungs. He showed that air in the blood-vessels was fatal; that one side of the thoraxmight be opened without danger to theanimal, but evidently did not recognizethe negative pressure there. He calculatedthe quantity of moisture carried off byrespiration. Finally he concludes his dis-cussion of the functions of the lungs withthis statement:

It is probable also that the blood may in thelungs receive some other important influencesfrom the air, which is in such great quantitiesinspired into them. It has long been the subjectof inquiry of many, to find of what use it is inrespiration, which tho' it may in some respectsbe known, yet it must be confessed that we arestill much in the dark about it.

In 1739 he was granted the Copley medaland the same year appeared "PhilosophicalExperiments" with the following title page:

solution made the air last longer for the purposes oflife."


PHILOSOPHICAL EXPERIMENTS

containing

Useful, and Necessary Instructions for suchas undertake long Voyages at Sea.

Shewing how sea-water may be made Freshand Wholsome: And how Fresh-water maybe preserved sweet.

How Biscuit, Corn, etc., may be secured fromthe Weevel, Maggots, and other Insects.

And Flesh preserv'd in hot climates, by saltinganimals whole.

To which is added

An account of several experiments and observa-tions on Chalybeate or Steel-Waters: Withsome attempts to convey them to distantplaces, preserving their Virtue to a GreaterDegree than had hitherto been done.

Likewise a Proposal for cleaning away Mud,etc. out of Rivers, Harbours and Reser-voirs.

Which were read before the Royal Society, atseveral of their Meetings.

By STEPHEN HALES, D. D., F. R. S.

Rector of Farrington in Hampshire, and Minis-ter of Teddington, Middlesex.

LONDON

Printed for W. Innys and R. Manby, at theWest end of St. Pauls; and T. Woodward,at the Half-Moon between the Temple-Gates, in Fleet-Street.

MDCCXXXIX

The practical side of these experimentsis obvious. Hales was ever conscious thathe was not a physician and upon mattersclinical he was very careful of his state-ments. He had the greatest respect for

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physicians but for quacks he had no sym-pathy. The following quotation from thisvolume leaves no doubt of his position andgives us some indication of the amount ofquackery in England in the eighteenthcentury:

Did I indeed hereby seek only popularapplause and not the real benefit of Mankind;the more ignorant I was in Physick, the betterchance I should have, to be much cryed up bythe unknowing Many: The Truth of this, wemay have had full proof of, of late Years, inthe Instances of several most ignorant Quacks;who have in their turns had a more generalCry of Applause given them, than has come tothe share of the most eminent and skilfulPhysicians, with many of which that Facultyabounds. But the Physicians may well becontent to take this contempt more patiently,when they reflect that a petulant fondness forQuackery is the epidemical Disease of thisAge; not only in opposition to theirs, but alsoto other Professions.

In May, 1741, he read before the RoyalSociety an account of a method for ventilat-ing ships. In November of the same yearCromwell Mortimer, M.D., secretary of theRoyal Society, had a letter from MartinTriewald, F.R.S., captain of mechanics andmilitary architect to the King of Sweden,saying that in the past spring he hadinvented a machine for the use of hisMajesty's men-of-war in order to draw outall bad air from under their decks. Histreatise was laid before the Royal Academyof Sweden, April 3, 1742, eleven months


after Hales' plan was laid before the RoyalSociety. Neither knew of the work of theother, yet their plans were almost identical.Each consisted of a box-Iike bellows fordrawing' out the foul air. They were even-tually adopted by all the nations havingsea-going vessels. Vessels carrying Africannegroes to the United States, for example,often lost as much as twenty-five per centof their cargo. This loss was reduced tofive per cent or less. One French vesselsaved 308 out of 312 slaves in spite of amost tedious calm and a long voyage.

In April, 175 2, ventilators were fixedin Newgate prison. These were operatedby a windmill. The death rate was reducedin this prison by the one measure alonefrom eight to two per month. Other prisonsadopted the method of ventilating used atNewgate. Louis xv was persuaded'to intro-duce this system of ventilating into theFrench prisons in which British soldierswere confined. On this occasion Hales iscredited with saying: "He hoped nobodywould inform against him for correspondingwith the enemy." The ventilator was foundvery useful in aerating granaries to preventthe grain from spoiling.

Among the many other tracts by Haleswas one entitled, "A Friendly Admonitionto Drinkers'of Brandy and other DistilledSpirits," which was widely distributed evenmany years after his death. A few of thetitles taken from the Philosophical Trans-actions of the Royal Society are: "A Proposalto Bring Small Passable Stones Soon and

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with Ease out of the Bladder" 2 ; "Remarksconcerning Some Electrical Experiments" 3;"Of the Strength of Several of the PrincipalPurging Waters, Especially That of Jessop'sWeil" 4 ; "Of Some Trials to Keep Waterand Fish Sweet, with Limewater," 5 and"A Description of a Sea Gage, to MeasureUnfathomable Depths."'

Hales was familiar with Franklin's experi-ments with electricity. When he was con-triving a means to abate hurricanes byexploding the sulphurous air (the collectionof which he thought the cause) by shootingbombs or grenades into the air, he says :"In Pennsylvania, Mr. Franklin havingfixed a vessel of spirit of wine and iron wireto the tail of a kite, the spirit of wine wasfixed in a sulphurous and consequently ahighly electrical state of the air." He studiedearthquakes and ascribed to them the samecause, volcanic sulphurous charged air. Inthis consideration he quotes Buffon andBorelli. About Lord Berkeley's "Tar Water"he had little to say; however, he thoughtit beneficial in murrain among cattle.

Hales was ever faithful to his mission asa minister. His flock always had his solici-tude. He helped them to get a supply of goodwater (1754). He enlarged the church yard"by prevailing upon the lord of the manor."He aided his parishioners in the construction

2 Pbil. Tr., Lond., ix, 159.3 Ibid., Ix, 543•4 Ibid., x, 48.

Ibid., x, 551.Gentleman's Magazine, May, 1754, xxlv, 215.


of a lantern on the church (1748). Later(1754) the timber tower on which thelantern stood was torn down and a brickone put in its place, a large share of thecost of which he himself bore. Under thistower his bones rest in accordance with hisrequest.

Regarding his personality; we have thefollowing remark from Pope: "I shall bevery glad to see Dr. Hates, and alwayslove to see him; he is so worthy and gooda man. 15

Others spoke of "his constant sincerityand cheerfulness of mind." The wickedhe "considered only like those experimentswhich upon trial, he found could never beapplied to any useful purpose, and whichhe therefore calmly and dispassionatelylaid aside."

In a trembling hand his signature appearson the parish register for the last time inNovember, 1760. After a short illness, thenature of which we do not know, he diedJanuary 4, 1761. The Gentlemen's Magazineof that date writes in part:

On Sunday the 4th instant, died, at hisparsonage-house at Teddington, universallylamented, in the 83rd year of his age, the Rev.Dr. Stephen Hales, F.R.S., member of theroyal academy of sciences of Paris and clerkof the closet to her Royal Highness the PrincessDowager of Wales. If any man might ever besaid to have devoted his whole life to the public,to all mankind, it was Dr. Hales.

Hales' philosophy was of the most prac-tical type. He enjoyed his work because of

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the benefit he might be able to render hisfellow men. It was not solely a pastime tohim. In the dedication to his book onventilators' we find this:

The study of natural philosophy is not amere trifling amusement as some are apt toimagine; for it not only delights the mind, andgives it the most agreeable entertainment inseeing in everything the Wisdom of the greatArchitect of Nature: But it is also the mostlikely means to make the gift of kind providenceto us by teaching us how to avoid what is hurtfuland to pursue what is most useful and beneficialto us.Again in the introduction to "Haema-staticks" we read :

In natural philosophy, we cannot depend onany mere Speculations of the Mind; we canonly with Mathematicians reason with anytolerable Certainty from proper Data, such asarise from the united Testimony of many goodand credible Experiments.

Yet it seems not unreasonable on theother hand tho' not far to indulge yet to carryour Reasonings a little further than the plainEvidence of Experiments will warrant; since atthe utmost boundaries of those Things whichwe clearly know, there is a kind of Twilightcast from what we know, on the adjoining Bor-der of Terra incognita, it seems thereforereasonable in some degree to indulge Conjecturethere; otherwise .we should make very slowAdvances in future Discoveries, either byExperiments or Reasoning.

A clergyman of the church of England,not having taken a medical degree nor

Hales, S. A. Treatise on Ventilators, Lond., Pt.1 and II, 1734, 1758.


having studied medicine, Hales stands outa unique figure in medical history. Hedrank deep of his religion and in it he sawnothing that would obstruct the progressof man and his civilization. In him therewas perfect blending of religion, philosophyand science. In breadth of detail and accu-racy of investigative procedure he standsunparalleled. His work was always quantita-tive. Hygiene and sanitary engineering mademarked advances by his efforts. He is theundisputed father of the science of hemo-dynamics, a contribution which giveshim rank with Harvey in the history ofphysiology.

In Westminister Abbey there stands amonument erected in his memory by thePrincess of Wales. On the tablet at the oldchurch in Teddington is this inscription:

Here is interred the body of Stephen Hales,D.D., clerk of the closet to the Princess of Wales,who was minister in this parish 51 years. Hedied the 4th of January, 1761, in the 84th yearof his age.

BIBLIOGRAPHY

Gentlemen's Magazine, 1 764, pages 34 and 273, andmany other articles previous to this date.

Phil. Tr., Lond., 1744 to 1755. Several references.Dictionary of National Biography. Lond., 1899.DAWSON, P. M. Biography of Stephen Hales. Johns

Hopkins Hosp. Bull., Balt., 1904, xv, 185, 232.STIRLING, W. Some Apostles of Physiology. Lond.,

1902.GARRISON, F. H. History of Medicine. Ed. 3. Phila.,

1921.FOSTER, SIR M. Lectures on the History of Physi-

ology. Cambridge, .190

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