July 29, 1922] 



NA TURE 



153 



nostrums as horse-dung and well-kept human urine 

 occupy an honourable place in the pharmacopoeia, and 

 that a custom appears to linger by which, when the 

 practitioner has done his best — or worst — and failed, 

 the sendees of another official are called in. He is the 

 " despenador " or " putter out of pain." I need say 

 no more of his or her duties than to give the following 

 quotation from Bensley's " Spanish and English 

 Dictionary " : " Despenadora — a woman who is 

 supposed to push her elbow into the stomach or- breast 

 of dying persons to relieve them from agony." 1 



It seems clear then that the Cholo, not the Cholo of 

 Cerro de Pasco or Oroya, but of some of the far out- 

 lying districts, has been little touched by the Spanish 

 or even the Inca civilisation, and that in him we have 

 a subject for physiological research whose like has 

 varied little for generations. In physique he is short 

 in stature and sallow, or with some blood in his cheeks. 

 That part of his anatomy which was principally of 

 interest to our party was his chest. We made a con- 

 siderable number of chest measurements. As regards 

 the chest circumference the following statement sums 

 up our findings. We based our measurements on 

 Prof. Dreyer's tables, accepting his estimate of the 

 normal ratio between the trunk length and the chest 

 circumference. We ascertained that the average 

 circumference of the Cholo chests which we measured 

 would normally be 79 cm. It was, in point of fact, 

 92 cm. As a rough check we measured our own 

 trunk chest ratios and those of the American and British 

 engineers, a community of fine physical development. 

 The circumference of the Anglo-Saxons was little in 

 excess of Dreyer's estimate. The lowest level at which 

 we came across one of these small people with chests 

 which appeared out of proportion to the rest of his 

 stature was at Matucana (8000 ft.), and on inquiry 

 we found that he was a native of Huancayo (12,000 ft.). 



To pass to the more strictly physiological aspects of 

 the work of the expedition, one must reflect that the 

 desire to investigate mountain sickness goes back at 

 least to the middle of the last century. It is remark- 

 able, when one comes to think of it, how recently our 

 knowledge of the causation of disease has grown. 

 The lure of mountain sickness to the physiologist lay 

 originally in the fact that it was a disease to which a 

 definite cause could be assigned. You go a certain 

 height up the mountain — any mountain — and when 

 yi iur ascent corresponds to a given fall in the barometer 

 you suffer from mountain sickness ; when you descend, 

 the malady leaves you. Mountain sickness, or as it is 

 called in Peru, " seroche," seemed to form a sort of 

 opening into the aetiology of disease. 



In recent years the centre of interest has to some 

 extent shifted. The cause of mountain sickness is 

 universally regarded as insufficient oxygen supply to 

 the tissues of the body, though there may still be some 

 doubt as to the directness of the connexion between 

 the deficiency of oxygen pressure in the blood and the 

 activity of the nerve cells responsible for the continence 

 of food in the stomach. Interest latterly has centred 

 rather around the methods which the body has at its 

 disposal for adapting itself to such a condition. But 

 the same thread still runs through the fabric ; this 



1 I am indebted for this quotation and much else to Mr. Murdock, manager 

 of the coal mine at Quishuarcancha. 



NO. 2752, VOL. I IO] 



particular instance of adaptation to environment is 

 studied because our knowledge of the conditions with 

 which the body has to deal are so exact and the con- 

 ditions themselves so easily produced or abolished. 



Partly, of course, it has another interest, namely, 

 that imperfect oxygenation of the blood is a factor in 

 a number of pulmonary complaints and an analysis 

 of those complaints demands an investigation of this 

 particular factor. That is the definitely medical aspect, 

 of which I shall say but little. Rather I shall turn my 

 attention to the extent to which adaptation can take 

 place, and the means by which it is brought about. 



Some of the Cholos appear at first sight to have 

 acquired an astonishing capacity for physical effort 

 at high altitudes. An example may be cited. Near 

 Cerro de Pasco there is a mine worked in the old 

 Spanish way. The ore is raised from the bowels of 

 the earth on the backs of porters, who carry their 

 loads up a rude staircase. The mine is about 250 feet 

 below the surface, and the staircase about 650 feet in 

 length. It opens under a sort of hut. The first porter 

 whom we saw emerge was a little fellow, who said 

 that he was ten years old. We so far doubted his 

 word as to place his age at thirteen or fourteen years. 

 He had on his back a bad of ore which I estimated at 

 40 lbs. — and that at an altitude at which the barometer 

 stood at only 458 mm., or about 18 inches. Shortly a 

 more mature boy appeared — perhaps seventeen or 

 eighteen years of age — his load was about 100 lbs. 

 To understand these feats, it must be remembered 

 that exercise may be of two kinds, spasmodic or con- 

 tinuous. In the case of continuous exercise, such as 

 that of long-distance running, the subject must maintain 

 an approximate equilibrium between the oxygen which 

 he uses and that which he absorbs. His oxygen 

 account must, so to speak, balance approximately at 

 any given time. In the case of spasmodic exercise 

 it is otherwise. If the subject is prepared for the 

 exercise to cease after a very short time, he mav ex- 

 pend oxygen at a greater rate than he takes it in, and 

 thus overdraw his oxygen account. A limit is, how- 

 ever, set to the overdraft, and when that limit is 

 reached he must rest till his oxygen account has 

 righted itself. This formed the subject of a most 

 interesting investigation carried out by Dr. Lupton 

 recently in the laboratory of Prof. A. V. Hill. The 

 porters in the old Spanish mine raise their loads by 

 a series of spasmodic efforts, each of which is followed 

 by a rest of considerable length accompanied by great 

 respiratory distress. 



Of the means by which the bod} - acclimatises itself 

 to oxygen want, real or alleged, we investigated the 

 following : . 



1. Secretion 0/ oxygen by the pulmonary epithelium. 

 Numerous direct estimations were made of the oxygen 

 pressure in the arterial blood, and in the alveolar 

 air. The two usually came out within two or three 

 millimetres of one another, which is approximately the 

 experimental error of the method. Such a coincidence 

 can only mean that the oxygen passes into the blood 

 by a process of diffusion through the very attenuated 

 partition of epithelium which separates the air from 

 the blood in the lung. Thus the view that the lung 

 could enable the body gradually to overcome the 

 effects of altitude by creating a sort of forced draught 



