376 



NATURE 



\_August 1 6, 1888 



to this wonderful survey of the earth, so that what appears very 

 •extraordinary to the reader may appear more likely when thus 

 illustrated, I have been at the pains to construct this globe." 

 The differences between this and former globes are considerable, 

 and mark a great advance in geographical knowledge. America, 

 instead of being broken up into many islands, as in all earlier 

 globes,'is shown as one large continent of tolerably correct shape ; 

 Florida is named for the first time in print; " the Moluccas 

 have found a local habitation and their true places, as well as 

 many of the real isles of the sea, while all the monsters and 

 bogus elements of American geography are made to disappear." 



The new volume issued by Mr. Stevens opens with a long, 

 learned, and most interesting introduction by Mr. Coote, on 

 •early American geography generally, and especially on the 

 globes and maps of the first part of the sixteenth century. Mr. 

 Coote also narrates the life of Schoner, and furnishes an 

 estimate of his services to geography. One of his discoveries 

 relating to Schoner is that the place-name Timiripa, from 

 which he dates some of his letters, and which has hitherto 

 puzzled all students, is merely the translation of part of the name 

 of a small parish of which Schoner was pastor. The intro- 

 duction is followed by a facsimile of Schoner's letter of dedica- 

 tion of the globe to the Canon of Bamberg, by the letter of 

 Maximilianus, and by translations of both, as well as by a 

 bibliography of Schoner's works. But, next to the introduction, 

 the portion of the book which will receive most attention will 

 be the facsimiles at the end, which are as follows: (1) the 

 famous Hunt-Lenox globe, attributed to 1506-7 : (2) the Bou- 

 longer globe, supposed to have been executed in 15 14-17 ; (3) 

 Schoner's first globe of 1515 ; (4) his second globe of 1520 ; (5) 

 the third globe of 1523, "being the earliest geographical docu- 

 ment to delineate the first circumnavigation of the earth by the 

 Spaniards, 1519-22"; (6) the Portuguese so-called Cantino 

 map of 1502. The reproduction of the letters of Schoner and 

 Maximilianus Transylvanus have been done in exact facsimile 

 by the phototypographic process, all the defects and peculiari- 

 ties of the originals appearing with faithful minuteness. The 

 long-lost globe consists of twelve gores, and its distinguishing 

 feature is a line drawn completely round the circumference, 

 showing the route of Magellan's fleet in the first circumnavigation 

 df-the earth. 



The following message from Mr. Joseph Thomson and Mr. 

 Harved Crichton-Browne, transmitted by the Eastern Telegraph 

 Company's cable from Tangier, has been sent to the Royal 

 Society, the Royal Geographical Society, and to the friends of 

 the explorers : — " City of Morocco, July 28. — We returned to 

 Amsmiz across mountains, safe and well, July 24 ; many in- 

 teresting geographical and geological notes ; so far successful 

 beyond our expectations. We were prevented going direct from 

 Glamoa to Gundaffy by tribal revolt. We shall start on August 6 

 for third trip across the Atlas, further south-west this time." 



M 1 



THE GASES OF THE BLOOD} 



R. PRESIDENT AND GENTLEMEN,— The subject I 

 have chosen is a consideration of the gaseous constituents 

 of the blood in relation to some of the problems of respiration- 

 This has been selected both because it deals with a province of 

 physiology in which there are many profound problems connected 

 with the molecular phenomena of life, and also because it gives 

 me the opportunity of illustrating some of the methods of physio- 

 logical research. I purpose to treat the subject chiefly from the 

 physical stand-point, and to demonstrate some of the phenomena 

 as I would endeavour to do to a class of students, believing that 

 this will be of more interest to many of my audience than if I 

 placed before you anything like an encyclopaedic account of 

 recent researches. I cannot help adding that as I speak in the 

 class-room of one of the most distinguished physicists of the day, 

 1 feel the genius of the place is hovering over me, and I will be 

 impelled to guide you to the borderland of physics and of 

 physiology. It is in this territory that we meet with the most 

 profound questions regarding the nature of vital activity, and it 



1 Address to the British Medical Association at its annual meeting at 

 Glasgow. Delivered on August 10 in the Natural Philosophy class-room 

 University of Glasgow, by John Gray McKendrick, M.D., LL.D., F.R.SS.L. 

 and E., F.R.C.P.E., Professor of the Institutes of Medicine in the University 

 of Glasgow. 



is here that the physiologist and the physicist must join hands in 

 working out their solution. 



Respiration may be shortly defined as the function or group of 

 functions by which an interchange occurs between the gases 

 formed in the tissues of a living being and the gases of the 

 medium in which it lives. It is interesting to take a brief survey 

 of the investigations which laid the foundations of our know- 

 ledge of this subject, as it illustrates to us the fact taught by the 

 history of all sciences that those truths which we now regard as 

 elementary were at one time unknown, and have been gained 

 only by laborious inquiry. 



The oldest writers do not appear to have had any clear notions 

 even as to the necessity for respiration. Hippocrates dimly 

 recognized that during breathing a spirilus was communicated 

 to the body. Many of the older anatomists, following Galen, 

 thought that the " very substance of the air got in by the vessels 

 of the lungs to the left ventricle of the heart, not only to 

 temperate heat, but to provide for the generation of spirits." 

 This notion of cooling the blood was held by Descartes (1596- 

 1650) and his followers, and seemed to them to be the chief, if 

 not the sole, use of respiration. In- addition, they supposed it 

 aided in the production and modulation of the voice, in coughing, 

 and in the introduction of odours. The celebrated Van Helmont 

 (1577-1664) strongly expresses these views, and attaches 

 particular importance to the necessity for cooling the blood, 

 which otherwise would become too hot for the body. 



About the middle of the seventeenth century clearer notions 

 began to prevail. These rested partly on an anatomical and 

 partly on a physical discovery. Malpighi (1621-94) discovered 

 that the minute bronchial tubes end in air vesicles, or mem- 

 branous cavities, as he termed them, on the walls of which, in 

 the frog, he saw with his simple microscope the blood flowing 

 through capillaries. This pulmonary plexus was for many years 

 termed the"rete mirabile Malpighii. " The physical observa- 

 tions were made by the celebrated Robert Boyle (1627-91), who 

 describes in his treatise entitled "New Experiments, Physico- 

 Mechanical, touching the Spring of the Air," published in 1662, 

 numerous experiments as to the behaviour of animals in the 

 exhausted receiver of the air-pump. He showed that the death 

 of the animals " proceeded rather from the want of air than that 

 the air was over-clogged by the steam of their bodies." He also 

 showed that fishes also enjoyed the benefits of the air, for, said 

 he, "there is wont to lurk in the water many little parcels of 

 interspersed air, whereof it seems not impossible that fishes may 

 make some use, either by separating it when they strain the 

 matter thorow their gills, or by some other way." 



His conclusion is " that the inspired and expired air maybe 

 sometimes very useful by condensing and cooling the blood ; " 

 but " I hold that the depuration of the blood in that passage is 

 not only one of the ordinary but one of the principal uses of 

 respiration." Thus, by the use of the air-pump, invented by 

 Otto von Guericke about 1650, Boyle was able to make a 

 contribution of fundamental importance to physiological 

 science. 



He also first clearly pointed out the real cause of the influx of 

 air into the lungs. The older anatomists, from Galen downwards, 

 held that the lungs dilated actively, and thus sucked in the air ; 

 and there was much controversy as to whether the chest, with 

 the contained lungs, resembled a pair of bellows, which was 

 filled because it was dilated, or whether the lungs resembled a 

 bladder, which is dilated because it is filled. Boyle shows 

 clearly that the cavity of the chest is actively dilated, and that 

 the lungs are distended because the "spring" of the air is then 

 less on their outer than on their inner surface. This simple ex- 

 planation was not generally accepted, because the minds of 

 Boyle's contemporaries were under the influence of an ancient 

 idea that air existed in the cavity of the chest external to the 

 lungs. This prevented them from seeing the simplicity and 

 accuracy of Boyle's explanation, and to be constantly on the 

 outlook for some mechanism by which the lungs could actively 

 dilate. Such notions were held by Willis, Malpighi, and 

 Erasmus Darwin. The opinion of Darwin is shown by the 

 following passages in the " Zoonomia " : — 



" By the stimulus of the blood in the right chamber of the 

 heart, the lungs are induced to expand themselves, and the 

 pectoral and intercostal muscles and the diaphragm act at the 

 same time by their associations with them." And, again, "to 

 those increased actions of the air-cells are superadded those oi 

 the intercostal muscles and diaphragm, by irritative association. 



Boyle's observations were published in 1660, and in 1685 we 



