STEPHEN HALES* (1677-1761) By G. E. BURGET PORTLAND, ORE. TEPHENS HALES was born at Bekes- Francis Darwin we learn that these two bourne in Kent, September 7, 1677, college friends roamed the surrounding the sixth son of Thomas and Mary country together. Hales carried an often- Hales. Only meager information is thumbed copy of Ray’s “Catalogue of obtainable in regard to his early life and Plants.’’ Everything from fossils to butter- training. In 1696, at the age of nineteen, flies was eagerly studied by the young he entered Bennet College, Cambridge. philosophers. They dissected frogs, dogs Although we have no definite record we and other animals together. John Francis may assume that he applied himself ear- Vigani (1650-1712) who became the first nestly to the study of religion and natural professor of chemistry at Cambridge in philosophy. He took a Bachelor of Arts 1703, seems to have attracted them. In a degree and was elected to a fellowship room at Trinity College, the laboratory of about 1702. In 1703 he was granted a Sir Isaac Newton, they repaired to repeat Master of Arts degree. William Stukclcy some of Boyle’s experiments and to watch (1687-1765) afterwards m.d ., f .r .s ., went the demonstrations of Vigani. They pre- to the college in 1704. A friendship arose pared various substances, “some of use, between him and Hales although Hales some of curiosity.’’ Hales studied astronomy. was Stukeley’s senior by ten years. From He knew well the Newtonian System. *Read before the University of Oregon Medical While yet in college he constructed a History Club, Portland, Orc., November 21, 1924. machine of brass to show the movements of all the planets. After having been in college lished in 1727 under the title of “Vegetable some twelve years (1696-1708-9) we next Staticks; or, an Account of Some Statical hear of him being made perpetual curate Experiments on the Sap in Vegetables; of Teddington, about 1710. He took orders being an essay towards a Natural History and in 1711 became a Bachelor of Divinity. Vegetation. Also a specimen of an attempt The next fifty years, until his death in to analyse the air by a great variety of 1761, his home was in Teddington, Middle- chymio-statical experiments, which were sex, where Alexander Pope was a friend and read at several meetings of the Royal neighbor and Peg Woffington one of his Society.” The work was well received and a parishioners. second issue was published in 1731. The Society further honored him by making him a member of the council, 1727. Hans Sloane (1660-1753) was at that time president of the Society. Upon the death of Sloane, 1753, Hales was elected to the French Academy to fill his place. “Vegetable Staticks,” as the more elabo- rate title indicates, deals with the flow of sap in plants of various kinds and the effect of moisture, temperature and types of soil on the pressure under which sap rises. The mercury manometer was used for these determinations, which were always carefully and accurately worked out. The book contains many drawings which prove the ingenuity and care with which the experiments were conducted. In all there arc 124 experiments, painstakingly recorded. They represent the original work on vege- He was married to Mary, daughter and table statics and opened at the time a new heiress of Dr. Newce, rector of Halisham, and fascinating field of plant physiology. about the year 1719, the exact date is Buffon (1707-1788), the French naturalist, uncertain. Mary died two years later, 1721, translated the work into French. German leaving no children. He never married and Italian translations soon followed. No again. doubt this work early fell into the handsof Although we have none of his experi- Linne (1707-1778), then a young man mental data before 1719 there can be little preparing his first work, “Systema Naturae” doubt that Hales was busy, as evidenced (1735).' Sachs (1832-97), the well-known by the fact of his election to the Royal German botanist, writes that of the study Society in 1718. In 1719 he reported to the of plant physiology that took place in the Society some recent experiments on the eighteenth century, the work of Hales effect of the sun’s warmth in raising the sap was the most original and the most impor- in trees. For this he received the thanks of tant contribution. In honor of Hales, John the Society with encouragement to continue Ellis, whom Linnaeus termed “The bright the research. This Hales did, reporting star of Natural History,” named a newly before the Society at different times, and in discovered genus, Halesia. June, 1725, he gave an account of his Intending at first only to make additional progress in the form of a treatise. At the observations and experiments to the volume request of the Society the work was pub- on “Vegetable Staticks” he found in 1733 that these had grown to the size of another it was at its full height, it would rise and fall at volume. This he called “Hacmastaticks,” and after each pulse 2, 3 or 4 inches; . or Volume n of the “Statical Essays.” Then I took away the glass tube, and let the The following paragraphs give an insight blood from the artery mount up in open air, into his purpose: when the greatest height of it’s jet was not above 2 feet. As the animal Body consists not only of a I measured the blood as it ran out of the wonderful texture of solid Parts, but also of a artery, and after each quart was run out, I large proportion of Fluids, which are continually refixed the glass tube to the artery to see how circulating and flowing, thro’ an inimitable much force the blood was abated; this I repeated Embroidery of Blood-Vessels, and other incon- to the 8th quart, and then its force being much ceivably minute Canals: And as the healthy abated, I applied the glass tube after each pint State of the Animal principally consists, in the had flowed out. maintaining of a due Equilibrium between Three horses in all were used in this those Solids and Fluids; it has, ever since the manner, all of which were to have been important Discovery of the Circulation of the killed as unfit for service. From one of the Blood, been looked upon as a matter well worth horses he measured the blood lost by the inquiring into, to find the Force and Velocity with which these Fluids are impelled; as a likely bleeding and after adding the probable means to give a considerable Insight into the amount in the large veins estimated the animal Oeconomy. total as five wine gallons, which he recog- It may not be improper here to take notice, nized as low, remarking that: “There is that being about twenty-seven years since, doubtless considerably more, but it is not reading the unsatisfactory conjectures of several, easy to determine how much.” The jugular about the cause of muscular motion, it occurred pressure in one of the horses he found to be to me, that by fixing tubes to the arteries of twelve inches when quiet, but this rose live animals, I might find pretty nearly, whether to fifty-two inches when the animal the blood, by its mere hydraulic energy, could struggled. have a sufficient force, by dilating the fibres of Experiments similar to these were done the acting muscles, and thereby shortening on sheep and dogs and he says: “Whatever their lengths, to produce the great effects of experiment I principally intended to make muscular motion. And hence it was, as I men- tioned in the preface to Vol. i, that I was insen- on any dog, I usually began with fixing a sibly led on from time to time into this large field tube first to the jugular vein and then to of statical and other experiments. the carotid artery.” He filled a number of hearts with melted He then proceeds to describe the classical wax, later cutting away the tissue and esti- experiments by which blood-pressure was mating carefully the inner surface of the first measured: ventricles. Knowing the volume and inner In December I caused a mare to be tied down surface of the ventricles, the blood pressure, alive on her back; she was 14 hands high, and heart rate, the diameter of the aortic orifice about 14 years of age; had a fistula on her and of the aorta itself, he calculated for withers, was neither very lean nor yet lusty; horses and various other animals including having laid open the left crural artery about man, the mean velocity of the I^Iood in the three inches from her belly, I inserted into it a aorta, the velocity of the systolic output brass pipe whose bore was one-sixth of an inch and the pressure sustained by the heart in diameter, and to that, by means of another during contraction. Although we now know brass pipe which was fitly adapted to it, I fixed a glass tube, of nearly the same diameter, such an estimate would be more or less which was nine feet in length: then untying the inaccurate, nevertheless this carried the ligature of the artery, the blood rose in the tube study of the circulatory system beyond 8 feet 3 inches perpendicular above the level Harvey’s work and introduced the method of the left ventricle of the heart; . when of quantitative investigation. Hales himself appreciated the complexity of the situation scheme by which the vessels were placed regarding the velocity.